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Dipartimento di Scienze della Vita sede ex-Agraria

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2022 - Advances in Food, Bioproducts and Natural Byproducts for a Sustainable Future: From Conventional to Innovative Processes [Curatela]
Garcia, I. G.; Gullo, M.; Simal-Gandara, J.

The world population is expected to reach almost 10,000 million in 2050, which entails the need to focus on sustainability and its three pillars: the economy, the environment, and society. Within this context, it is necessary to use our resources efficiently; for instance, we will need to produce much more food using less land and while polluting less to optimize the production of biomass from diversified resources, along with its subsequent conversion, fractionation, and processing. To achieve this, new approaches and processes, with special emphasis from a biotechnological perspective, may need to be implemented to move towards a circular model that will confer environmental sustainability. Global projections of food losses constitute an abundant pool of complex carbohydrates, proteins, lipids, and functional compounds. Hence, the deployment of food waste streams as raw materials will encompass the formulation of added-value products that will be ideally reintroduced in the food supply chain to close the loop. Therefore, the analysis and optimization of any food and bioproduct process, as well as the development of innovative and emerging food and by-product processing methods, are important as a necessity for the sustainable transition to a bioeconomy era. The valorization, bioprocessing, and biorefining of food-industry-based streams, the role of industrial microorganisms, the isolation of high-added-value compounds, applications of the resulting bio-based chemicals in food manufacturing, novel food formulations, economic policies for food waste management, along with sustainability or techno-economic assessment of processing methods constitute subject areas that need to be addressed. More specifically, bioprocess design to valorize food-industry waste and by-product streams should be initiated by characterizing the composition of the onset raw material with the aim of identifying the target end-products, whereas the generation of multiple high-added-value products is a prerequisite for cost-effective processes to establish economic sustainability. On top of that, the feasibility of innovative processes could be sustained by encompassing food applications, driven by the constantly emerging consumers’ demand for functional foods and beverages with enhanced nutritional value. Equally, a growing awareness for bio-based and natural food components is being developed, thereby imposing challenges on the substitution of chemically derived ingredients with their natural counterparts.

2022 - Advances in Food, Bioproducts and Natural Byproducts for a Sustainable Future: From Conventional to Innovative Processes [Articolo su rivista]
Garcia, I. G.; Simal-Gandara, J.; Gullo, M.

2022 - Anti-Spoilage Activity and Exopolysaccharides Production by Selected Lactic Acid Bacteria [Articolo su rivista]
Iosca, Giovanna; De Vero, Luciana; Di Rocco, Giulia; Perrone, Giancarlo; Gullo, Maria; Pulvirenti, Andrea

In this study, eight lactic acid bacteria (LAB) strains, previously isolated from traditional and gluten-free sourdoughs, and selected for their potential in improving the sensory and rheological quality of bakery products, were screened against some common spoilage agents. The anti-mould activity was tested using strains of the species Fusarium graminearum, Aspergillus flavus, Penicillium paneum and Aspergillus niger. Regarding the antibacterial activity, it was assessed against four strains of the species Escherichia coli, Campylobacter jejuni, Salmonella typhimurium and Listeria monocytogenes. Furthermore, LAB strains were evaluated for their ability to produce exopolysaccharides, which are gaining considerable attention for their functional properties and applicability in different food industrial applications. A strain-specific behaviour against the moulds was observed. In particular, F. graminearum ITEM 5356 was completely inhibited by all the LAB strains. Regarding the antibacterial activity, the strains Leuconostoc citreum UMCC 3011, Lactiplantibacillus plantarum UMCC 2996, and Pediococcus pentosaceus UMCC 3010 showed wide activity against the tested pathogens. Moreover, all the LAB strains were able to produce exopolysaccharides, which were preliminarily characterized. The assessed features of the LAB strains allow us to consider them as promising candidates for single or multiple starter cultures for food fermentation processes.

2022 - Candidate Acetic Acid Bacteria Strains for Levan Production [Articolo su rivista]
Anguluri, Kavitha; LA CHINA, Salvatore; Brugnoli, Marcello; DE VERO, Luciana; Pulvirenti, Andrea; Cassanelli, Stefano; Gullo, Maria

In this study, twelve strains of acetic acid bacteria (AAB) belonging to five different genera were tested for their ability to produce levan, at 70 and 250 g/L of sucrose concentration, respectively. The fructan produced by the bacterial strains was characterized as levan by NMR spectroscopy. Most of the strains produced levan, highlighting intra- and inter-species variability. High yield was observed for Neoasaia chiangmaiensis NBRC 101099 T, Kozakia baliensis DSM 14400 T and Gluconobacter cerinus DSM 9533 T at 70 g/L of sucrose. A 12-fold increase was observed for N. chiangmaiensis NBRC 101099 T at 250 g/L of sucrose concentration. Levan production was found to be affected by glucose accumulation and pH reduction, especially in Ko. baliensis DSM 14400 T. All the Gluconobacter strains showed a negative correlation with the increase in sucrose concentration. Among strains of Komagataeibacter genus, no clear effect of sucrose on levan yield was found. Results obtained in this study highlighted the differences in levan yield among AAB strains and showed interdependence between culture conditions, carbon source utilization, and time of incubation. On the contrary, the levan yield was not always related to the sucrose concentration.

2022 - Date Fruits as Raw Material for Vinegar and Non-Alcoholic Fermented Beverages [Articolo su rivista]
Cantadori, Elsa; Brugnoli, Marcello; Centola, Marina; Uffredi, Erik; Colonnello, Andrea; Gullo, Maria

Nowadays foods and beverages with healthy and functional properties, especially those claimed to prevent chronic diseases, are obtaining more and more interest. As a result, numerous foods and beverages have been launched on the market. Among products with enhanced properties, vinegar and fermented beverages, have high potential of growth. Date palm fruits are a versatile raw material, rich in sugars, dietary fibers, minerals, vitamins, and phenolic compounds, thus they are widely used for food production, including date juice, jelly, butter, and fermented bever-ages, such as wine and vinegar. Moreover, their composition makes them suitable for the formu-lation of functional foods and beverages. Microbial transformations of date juice include alco-holic fermentation for producing wine as end product or as a substrate for acetic fermentation. Lactic fermentation is also documented for transforming dates juice and syrup. However, con-sidering acetic acid bacteria, little evidence is available on the exploitation of date juice by acetic and gluconic fermentation for producing beverages. This review presents an overview of date fruit’s composition, the related health benefits for hu-man health, vinegar and date-based fermented non-alcoholic beverages obtained by acetic acid bacteria fermentation.

2022 - Determination of antifungal volatile organic compounds of upland rice vinegar and their inhibition effects on Aspergillus flavus in dried chili pepper [Articolo su rivista]
Pothimon, R.; Krusong, W.; Daetae, P.; Tantratian, S.; Gullo, M.

Determination of volatile organic components (VOC) produced in high acid upland rice vinegar was conducted using GC-MS. Acetic acid and ethyl acetate at 9.11% and 2.69% (v/v), respectively, were major VOC found in the vinegar while the others were isobutyl acetate, isobutyl alcohol, isoamyl acetate, isoamyl alcohol, phenethyl acetate and phenethyl alcohol. Subsequently, vinegar and VOC were tested, in vitro, for their inhibition on conidia germination of 103 conidia/mL of Aspergillus flavus. The exposure with 10% (v/v) of vapor-phase vinegar and pure acetic acid completely inhibited the germination of conidia with 30 min exposure, while VOC mixture of 9.11% (v/v) acetic acid, 0.08% (v/v) isoamyl alcohol, 0.45% (v/v) phenethyl alcohol and 0.01% (v/v) isobutyl alcohol with 45 min exposure could achieve the same target. Then, vinegar vapor was tested on the inhibition of conidia germination and aflatoxin production of A. flavus during 90 d subsequent storage of dried chili pepper. Complete inhibition of conidia germination and aflatoxin production were achieved with the 40 min exposure of 1.04 ± 0.03 mmol/L of vaporized vinegar. Our results showed that fumigation of upland rice vinegar containing antifungal VOC is a simple and an economical method for commercial preservation of dried chili pepper. Upland rice vinegar is a novel bio-fumigant for prevention of mycotoxin production in dried food and feed products during storage.

2022 - Probiotics in dairy products: Microencapsulation and delivery [Monografia/Trattato scientifico]
Gullo, M.; Zotta, T.

Dairy products (including yogurt, fermented milks, cheeses, frozen desserts and ice-cream) are suitable carriers of probiotic strains. Probiotics used as adjuncts in dairy foods mainly belong to lactobacilli and Bifidobacteria groups. The inclusion of probiotics in dairy matrices may impair the vitality and performances of strains because of several stressors involved in production technology and storage processes (e.g., fermentation temperature, packaging type, heat treatment, homogenization, interaction with other ingredients and microorganisms). Survival of probiotics in food matrices, and then in human gut, is a key factor to ensure the health benefits to human hosts.

2021 - A new Ciboria sp. for soil mycoremediation and the bacterial contribution to the depletion of total petroleum hydrocarbons [Articolo su rivista]
Di Gregorio, Simona; Becarelli, Simone; Chicca, Ilaria; La China, Salvatore; Siracusa, Giovanna; Bardi, Alessandra; Gullo, Maria; Petroni, Giulio; Bernard Levin, David

A Ciboria sp. strain (Phylum Ascomycota) was isolated from hydrocarbon polluted soil of an abandoned oil refinery in Italy. The strain was able to utilize diesel oil as a sole carbon source for growth. Laboratory-scale experiments were designed to evaluate the use of this fungal strain for treatment of the polluted soil. The concentration of Total Petroleum Hydrocarbons in the soil was 8538 mg/kg. Mesocosms containing the contaminated soil were inoculated with the fungal strain at 1% or 7%, on a fresh weight base ratio. After 90 days of incubation, the depletion of TPH contamination was of 78% with the 1% inoculant, and 99% with the 7% inoculant. 16S rDNA and ITS metabarcoding of the bacterial and fungal communities was performed in order to evaluate the potential synergism between fungi and bacteria in the bioremediation process. The functional metagenomic prediction indicated Arthrobacter, Dietzia, Brachybacerium, Brevibacterium, Gordonia, Leucobacter, Lysobacter and Agrobacterium sps. as generalist saprophytes, essential for the onset of hydrocarbonoclastic specialist bacterial species, identified as Streptomyces, Nocardoides, Pseudonocardia, Solirubrobacter, Parvibaculum, Rhodanobacter, Luteiomonas, Planomicrobium and Bacillus sps., involved in the Total Petroleum Hydrocarbons depletion. The fungal metabolism accelerated the onset of specialist over generalist bacteria. The capacity of the Ciboria sp. to deplete Total Petroleum Hydrocarbons in the soil in treatment was also ascertained.

2021 - Assessing effectiveness of Komagataeibacter strains for producing surface-microstructured cellulose via guided assembly-based biolithography. [Articolo su rivista]
Brugnoli, M.; Robotti, F.; China, La; Anguluri, K.; Haghighi, H.; Bottan, S.; Ferrari, A.; Gullo, M.

In this study, a medical device made of surface microstructured bacterial cellulose was produced using cellulose‑producing acetic acid bacteria wild‑type strains in combination with guided assembly‑based biolithography. The medical device aims at interfering with the cell’s focal adhesion establishment and maturation around implantable devices placed in soft tissues by the symmetrical array on its surface. A total of 25 Komagataeibacter strains was evaluated over a three‑step selection. In the first step, the ability of strains to produce a suitable bacterial cellulose layer with high production yield was examined, then nine strains, with a uniform and smooth layer of bacterial cellulose, were cultured in a custom‑made silicone bioreactor and finally the characteristics of the symmetrical array of topographic features on the surface were analysed. Selected strains showed high inter and intra species variability in bacterial cellulose production. The devices obtained by K2G30, K1G4, DSM 46590 (Komagataeibacter xylinus), K2A8 (Komagataeibacter sp.) and DSM 15973T (Komagataeibacter sucrofermentas) strains were pouched‑formed with hexagonal surface pattern required for reducing the formation of fibrotic tissue around devices, once they are implanted in soft tissues. Our findings revealed the effectiveness of the selected Komagataeibacter wild‑type strains in producing surface microstructured bacterial cellulose pouches for making biomedical devices.

2021 - Bioconservation of iron and enhancement of antioxidant and antibacterial properties of chicken gizzard protein hydrolysate fermented by Pediococcus acidilactici ATTC 8042 [Articolo su rivista]
Muhammed Moula Ali, Ali; Gullo, Maria; Kumar Rai, Amit; Charan Bindu Bavisetty, Sri

BACKGROUND The poultry industry is a fastest growing sector, and its processing industries generate considerable quantities of chicken gizzards (CG) every day. However, due to its hard texture, high microbial load, and cultural beliefs, it has low consumer preference. CGs are a substantial source of proteins, iron, and other nutrients, which can be effectively used to produce nutraceuticals, rich in peptides (antioxidants and antibacterial), bio‐iron, essential free amino acids, and fatty acids vital for human health. RESULTS Lactic acid fermentation of CG by Pediococcus acidilactici ATTC 8042 increased the antioxidant activity (DPPH, ABTS, and FRAP) up to 10 to 26 times compared to unfermented CG (p < 0.05). The degree of hydrolysis and solvents (ethanol and water) used for extracting protein hydrolysates significantly affected the antioxidant properties. Moreover, fermented CG showed negligible reduction in bio‐iron (2‐3%) compared to heat processed (85 °C for 15 min) ones, in which bio‐iron was reduced up to 20.3% (p < 0.05). Further, the presence of unsaturated fatty acids such as C20:4 and C22:4 n‐6 indicated low level of lipid oxidation. CONCLUSION Fermented CG, with its reasonably high antioxidant and antibacterial activity, together with a substantial amount of bio‐iron and other nutritional components can serve as a functional food or feed additive to reduce oxidative stress and treat iron deficiency.

2021 - Design of a New Fermented Beverage from Medicinal Plantsand Organic Sugarcane Molasses via Lactic Fermentation. [Articolo su rivista]
Gadhoumi, Hamza; Gullo, Maria; DE VERO, Luciana; Martinez-Rojas, Enriqueta; Saidani Tounsi, Moufida; Akrem Hayouni, El

Functional beverages obtained using medicinal plants and fermented with lactic acidbacteria are gaining much interest from the scientific community, driven by the growing demand forfood and beverages with beneficial properties. In this work, three different batches of medicinal plantsand organic sugarcane molasses, named FB-lc, FB-sp and FB-lcsp, were prepared and fermented byusingLactobacillus acidophilusATCC 43121,Bifidobacterium breveB632 and a mix of both strains’ culture,respectively. The three fermented beverages revealed a high level of polyphenols (expressed as gallicacid equivalent), ranging from 182.50 to 315.62μg/mL. The highest content of flavonoids (152.13μgquercetin equivalent/mL) and tannins (93.602μg catechin equivalent/mL) was detected in FB-lcsptrial. The IR spectroscopy analysis showed a decrease in sugar (pyranose forms, D-glucopyranoseand rhamnosides). In addition, the aromatic compounds of the fermented beverages, detected byGC-MS headspace analysis, showed twenty-four interesting volatile compounds, which could givepositive aroma attributes to the flavor of the beverages. The highest antioxidant activity was observedin the beverage obtained by the mix culture strains. Accordingly, the production of these beveragescan be further investigated for considering their well-being effects on human health.

2021 - Functional and Healthy Features of Conventional and Non-Conventional Sourdoughs [Articolo su rivista]
De Vero, Luciana; Iosca, Giovanna; Gullo, Maria; Pulvirenti, Andrea

Sourdough is a composite ecosystem largely characterized by yeasts and lactic acid bacteria which are the main players in the fermentation process. The specific strains involved are influenced by several factors including the chemical and enzyme composition of the flour and the sourdough production technology. For many decades the scientific community has explored the microbiological, biochemical, technological and nutritional potential of sourdoughs. Traditionally, sourdoughs have been used to improve the organoleptic properties, texture, digestibility, palatability, and safety of bread and other kinds of baked products. Recently, novel sourdough-based biotechnological applications have been proposed to meet the demand of consumers for healthier and more natural food and offer new inputs for the food industry. Many researchers have focused on the beneficial effects of specific enzymatic activities or compounds, such as exopolysaccharides, with both technological and functional roles. Additionally, many studies have explored the ability of sourdough lactic acid bacteria to produce antifungal compounds for use as bio-preservatives. This review provides an overview of the fundamental features of sourdoughs and their exploitation to develop high value-added products with beneficial microorganisms and/or their metabolites, which can positively impact human health.

2021 - Kombucha Tea as a Reservoir of Cellulose Producing Bacteria: Assessing Diversity among Komagataeibacter Isolates [Articolo su rivista]
LA CHINA, Salvatore; DE VERO, Luciana; Anguluri, Kavitha; Brugnoli, Marcello; Mamlouk, Dhouha; Gullo, Maria

Bacterial cellulose (BC) is receiving a great deal of attention due to its unique properties such as high purity, water retention capacity, high mechanical strength, and biocompatibility. However, the production of BC has been limited because of the associated high costs and low productivity. In light of this, the isolation of new BC producing bacteria and the selection of highly productive strains has become a prominent issue. Kombucha tea is a fermented beverage in which the bacteria fraction of the microbial community is composed mostly of strains belonging to the genus Komagataeibacter. In this study, Kombucha tea production trials were performed starting from a previous batch, and bacterial isolation was conducted along cultivation time. From the whole microbial pool, 46 isolates were tested for their ability to produce BC. The obtained BC yield ranged from 0.59 g/L, for the isolate K2G36, to 23 g/L for K2G30—which used as the reference strain. The genetic intraspecific diversity of the 46 isolates was investigated using two repetitive-sequence-based PCR typing methods: the enterobacterial repetitive intergenic consensus (ERIC) elements and the (GTG)5 sequences, respectively. The results obtained using the two different approaches revealed the suitability of the fingerprint techniques, showing a discrimination power, calculated as the D index, of 0.94 for (GTG)5 rep-PCR and 0.95 for ERIC rep-PCR. In order to improve the sensitivity of the applied method, a combined model for the two genotyping experiments was performed, allowing for the ability to discriminate among strains.

2021 - Mechanical and structural properties of environmental green composites based on functionalized bacterial cellulose [Articolo su rivista]
Barbi, S.; Taurino, C.; La China, S.; Anguluri, K.; Gullo, M.; Montorsi, M.

In this work TiO2 and highly inorganic ceramic clay were successfully immobilized into Bacterial Cellulose (BC), produced by Komagataeibacter xylinus K2G30 (UMCC 2756) strain, in different proportions. The morphology, structure, and mechanical properties of the composites, fabricated by wet mechanical mixing, were investigated through a multi-technique approach: density measurement, optical and electronic microscopy, FTIR spectroscopy, contact angle measurement and mechanical tensile testing, before and after aging, under UV light exposure. Results suggest completely different behavior by using TiO2 or Clay. In fact, porous fragile structures were obtained by employing Clay, whereas more compact and plastic-like specimen by using TiO2, due to different chemical bonding developed through H-bonding, as confirmed by FTIR. Enhanced tensile resistance at break was found for a content of TiO2 equal to 20 wt% and this result was not affected by aging, under UV light exposure. This study demonstrates how ceramic inorganic fillers for BC are able to act in completely different way, becoming of interests in different fields such as hydrophilic porous membranes for Clay and compact plastic-like film for textile industry with TiO2 addition.

2021 - Selection of Promising Exopolysaccharide-Producing Starter Cultures for Gluten-Free Sourdough [Abstract in Rivista]
Iosca, Giovanna; Febo, Camilla; Haghighi, Hossein; De Vero, Luciana; Gullo, Maria; Pulvirenti, Andrea

Celiac disease is an autoimmune enteropathy that affects the small intestine and is caused by the gliadin fraction of wheat gluten and other alcohol-soluble proteins (prolamines) of barley and rye in genetically predisposed subjects. Nowadays, the only recognized cure for this pathology is the use of gluten-free (GF) products. Although the market for GF products has grown in the last few years, their improvement is still a challenge for the food industry. With regard to GF bakery products, some of them can result in an unappetizing taste with a high fat content. These inconveniences can be minimized or solved by using sourdough fermentation. Sourdough is a stable culture of lactic acid bacteria (LAB) and yeast in a mixture of flour and water. In particular, GF sourdough represents a rich source of naturally occurring LAB and wild yeasts, which play important roles in food fermentation. This is mainly due to their potential in improving functional, technological, and probiotics properties, contributing to safe food with a better taste. Moreover, exopolysaccharide (EPS)-producing strains can also contribute to improving the sensory and rheological quality of the different GF products. This study aims to isolate and characterize the microbial pool from a GF sourdough made with rice flour and to evaluate the ability of selected LAB strains to produce exopolysaccharides (EPS). The yeast and LAB were isolated in selective agar media. A total of 220 isolates (110 yeasts and 110 bacteria) were obtained. They were taxonomically identified and characterized using both traditional and molecular approaches. Sequencing analysis of the D1/D2 domain of the 26S rRNA and the 16S rRNA genes, for yeasts and bacteria, respectively, revealed the occurrence of Saccharomyces cerevisiae as predominant yeasts and Lactiplantibacillus plantarum and Pediococcus pentosaceus as dominant LAB. Regarding the EPS production, 25 strains were able to produce dextran-like EPS with a maximum yield of 2 g/L. This study allowed the isolation and selection of promising EPS-producing starter cultures for the different types of flour sourdough, in particular, GF sourdough

2021 - Yeasts and Lactic Acid Bacteria for Panettone Production: An Assessment of Candidate Strains [Articolo su rivista]
De Vero, Luciana; Iosca, Giovanna; La China, Salvatore; Licciardello, Fabio; Gullo, Maria; Pulvirenti, Andrea

The recovery of yeasts and lactic acid bacteria (LAB) involved in sourdough fermentation is the first step in the selection of starters with suitable technological aptitude and capable of producing desired aromas and/or aromatic precursors. In this work, two sourdoughs samples (MA and MB) and the derived doughs (samples A and B) were collected from a bakery during artisanal Panettone manufacture. Yeasts and bacteria were isolated at different fermentation steps on selective agar media. A total of 77 isolates were obtained and characterized. Representative strains of yeasts and LAB were identified by sequencing the D1/D2 domain of the 26S rRNA and the 16S rRNA genes, respectively. Moreover, the volatile organic compounds (VOCs) produced in the collected samples were detected and correlated to the species found in the same samples. The results highlighted the occurrence of Kazachstania humilis in both samples A and B, while Saccharomyces cerevisiae strains were detected only in samples B. Among LAB, Fructilactobacillus sanfranciscensis was the main species detected in both sourdoughs. Furthermore, strains belonging to the species Lactiplantibacillus plantarum, Furfurilactobacillus rossiae, Lactobacillus parabuchneri, Leuconostoc citreum, and Leuconostoc mesenteroides were assessed in the dough samples.

2020 - Characterization of bio-nanocomposite films based on gelatin/polyvinyl alcohol blend reinforced with bacterial cellulose nanowhiskers for food packaging applications [Articolo su rivista]
Haghighi, Hossein; Gullo, Maria; La China, Salvatore; Pfeifer, Frank; Siesler, Heinz Wilhelm; Licciardello, Fabio; Pulvirenti, Andrea

Bacterial cellulose nanowhiskers (BCNW) were synthesized from Komagataeibacter xylinus (strain K2G30; UMCC 2756) using sulfuric acid hydrolysis and incorporated into a gelatin-polyvinyl alcohol (GL/PVA) blend film matrix. The effect of BCNW content (1–10 wt% of biopolymer) on the microstructural, mechanical, optical, and water barrier properties of bio-nanocomposites was studied. Transmission electron microscopy showed that BCNW had a needle shape morphology with an average length of 600 nm and an average width of 30 nm. The crystallinity index of BCNW was 94.7% using X-ray diffraction. Scanning electron microscopy (SEM) illustrated good miscibility between GL/PVA blend film matrix and BCNW up to 7.5 wt%. Fourier-transform infrared spectroscopy in the attenuated total reflection mode showed molecular interactions between functional groups of the GL/PVA blend film matrix and BCNW. The incorporation of BCNW up to 7.5% into the GL/PVA blend reduced the water vapor transmission rate and water vapor permeability by about 22% and 14%, respectively, while tensile strength, elongation at break, and elastic modulus increased by about 21.5%, 41% and 19%, respectively (p <0.05). Films transparency was not affected by the addition of BCNW (p >0.05) suggesting that the BCNW were dispersed uniformly at the nanoscale. All films were colorless (ΔE*<2) with low opacity value (<2) comparable to synthetic plastics. Overall, the characterization of functional properties revealed that GL/ PVA blend film reinforced with BCNW could be used as an environmentally friendly packaging material to partially replace or reduce the use of current petroleum-based packaging materia

2020 - Conducting High acetic acid and temperature acetification processes by Acetobacter pasteurianus UMCC 2951 [Articolo su rivista]
Pothimon, Ruttipron; Gullo, Maria; La China, Salvatore; Thompson, Anthony Keith; Krusong, Warawut

In this study Acetobacter pasteurianus strain UMCC 2951 was tested as a microbial starter to conduct acetification processes by repeatedly cultivation cycles under high temperature acetification at 40 ± 1 °C. Acid production and acetification rate increased with repeated cultures under high temperature acetification as adaptation period increased, but were still lower than acetification at 30 ± 1 °C. However, the addition of 0.15 % calcium chloride reduced the negative effects of 40 ± 1 °C on both acid production and acetification rate compared to 30 ± 1 °C. A strong decrease in fatty acids and phosphatidylethanolamine and increases in phosphatidylcholine and phosphatidylglycerol in cell membranes were found under high acid and high temperature acetification. In addition, transmission electron microscope images reveal a more compact cell wall when calcium chloride was added to the cultivation medium. The strategy used in this study confirmed that the use of acetic acid bacteria as microbial starters could be effective also at temperature above the optimal values, when acetification processes are managed through repeated semi-continuous cycles.

2020 - Exploring the Microbial Community of Traditional Sourdoughs to Select Yeasts and Lactic Acid Bacteria [Articolo su rivista]
Iosca, Giovanna; Vero, Luciana De; Gullo, Maria; Licciardello, Fabio; Quartieri, Andrea; Pulvirenti, Andrea

Sourdoughs represent an awesome example of ecosystem in which yeasts and lactic acid bacteria (LAB) interact with each other, defining the characteristics of the final product in terms of composition, texture, taste and flavor. Therefore, the identification of dominant yeasts and LAB involved in the fermentation process can lead to the selection of starters with suitable fermentation aptitude and capable of producing desired aromas and/or aromatic precursors. In this work, two sourdoughs samples (A and B) for Panettone production were collected from an artisan bakery. Yeasts and bacteria were isolated at different fermentation steps on selective agar media. A total of 120 isolates were obtained and firstly characterized by conventional microbiological methods. Afterward, genomic DNA was extracted from the cultures, and (GTG)5-PCR fingerprinting analysis was carried out to reduce the redundance among the isolates. Representative yeasts and LAB strains, having a unique profile, were identified by sequencing the D1/D2 domain of the 26S rRNA and the 16S rRNA genes, respectively. The results highlighted the occurrence of Kazachstania humilis and Fructilactobacillus sanfranciscensis in both sourdoughs. Among LAB, also some other strains belonging to Lactobacillus genus were found. Moreover, Saccharomyces cerevisiae and Staphylococcus spp. strains were detected in sample B. In this study, a pool of yeasts and LAB strains for producing starter cultures with specific technological traits for sourdoughs production was obtained.

2020 - Genome sequencing and phylogenetic analysis of K1G4: a new Komagataeibacter strain producing bacterial cellulose from different carbon sources [Articolo su rivista]
La China, S.; Bezzecchi, A.; Moya, F.; Petroni, G.; Di Gregorio, S.; Gullo, M.

Objective: The objective of this study was to evaluate the ability of a new Komagataeibacter xylinus strain in producing bacterial cellulose from glucose, mannitol and glycerol, and to assess the genome sequencing with special focus on bacterial cellulose related genes. Results: Bacterial cellulose production during 9 days of cultivation was tested in glucose, mannitol and glycerol, respectively. Differences in the bacterial cellulose kinetic formation was observed, with a final yield of 9.47 g/L in mannitol, 8.30 g/L in glycerol and 7.57 g/L in glucose, respectively. The draft genome sequencing of K1G4 was produced, revealing a genome of 3.09 Mbp. Two structurally completed cellulose synthase operons and a third copy of the catalytic subunit of cellulose synthase were found. By using phylogenetic analysis, on the entire rRNA operon sequence, K1G4 was found to be closely related to Komagataeibacter xylinus LMG 1515T and K. xylinus K2G30. Conclusions: The different yields of bacterial cellulose produced on glucose, mannitol and glycerol can be correlated with the third copy of bcsAB operon harboured by K1G4, making it a versatile strain for industrial applications.

2020 - Selection of Wine Saccharomyces cerevisiae Strains and Their Screening for the Adsorption Activity of Pigments, Phenolics and Ochratoxin A [Articolo su rivista]
Pulvirenti, Andrea; De Vero, Luciana; Blaiotta, Giuseppe; Sidari, Rossana; Iosca, Giovanna; Gullo, Maria; Caridi, Andrea

Ochratoxin A is a dangerous mycotoxin present in wines and is considered the principal safety hazard in the winemaking process. Several authors have investigated the ochratoxin A adsorption ability of Saccharomyces cerevisiae yeasts, and specifically selected strains for this desired trait. In the present work, a huge selection of wine yeasts was done starting from Portuguese, Spanish and Italian fermenting musts of dierent cultivars. Firstly, 150 isolates were collected, and 99 non-redundant S. cerevisiae strains were identified. Then, the strains were screened following a multi-step approach in order to select those having primary oenological traits, mainly (a) good fermentation performance, (b) low production of H2S and (c) low production of acetic acid. The preselected strains were further investigated for their adsorption activity of pigments, phenolic compounds and ochratoxin A. Finally, 10 strains showed the desired features. The goal of this work was to select the strains capable of absorbing ochratoxin A but not pigments and phenolic compounds in order to improve and valorise both the quality and safety of red wines. The selected strains are considered good candidates for wine starters, moreover, they can be exploited to obtain a further enhancement of the specific adsorption/non-adsorption activity by applying a yeast breeding approach.

2020 - Valorization of cheese whey using microbial fermentations [Articolo su rivista]
Zotta, T.; Solieri, L.; Iacumin, L.; Picozzi, C.; Gullo, M.

Cheese whey (CW), the liquid resulting from the precipitation and removal of milk casein during cheese-making, and the second cheese whey (SCW) derived from the production of cottage and ricotta cheeses are the main byproducts of dairy industry. The major constituent of CW and SCW is lactose, contributing to the high BOD and COD content. Because of this, CW and SCW are high-polluting agents and their disposal is still a problem for the dairy sector. CW and SCW, however, also consist of lipids, proteins, and minerals, making them useful for production of various compounds. In this paper, microbial processes useful to promote the bioremediation of CW and SCW are discussed, and an overview on the main whey-derived products is provided. Special focus was paid to the production of health-promoting whey drinks, vinegar, and biopolymers, which may be exploited as value-added products in different segments of food and pharmaceutical industries.

2020 - Vinegar production from Citrus bergamia by-products and preservation of bioactive compounds [Articolo su rivista]
Di Donna, Leonardo; Bartella, Lucia; De Vero, Luciana; Gullo, Maria; Giuffrè, Angelo M.; Zappia, Clotilde; Capocasale, Marco; Poiana, Marco; D’Urso, Silvia; Caridi, Andrea

Processing citrus fruits results in significant amount of wastes; however, citrus by-products still contain high amounts of polyphenolic and other bioactive value-added compounds. In addition, bergamot (Citrus bergamia) wastes contain two compounds—brutieridin and melitidin—which exhibit statin-like properties. Recently, novel fermented products containing bioactive compounds received increasing attention because of their health-promoting functions. In this study, the bioconversion of citrus wastes in vinegars with high content in bioactive and aromatic compounds was performed, detecting a high permanence at the end of the process of the main compounds of interest, especially brutieridin and melitidin. In addition, the sensory analysis of the vinegars was performed, obtaining good performances. According to the adopted preselection procedure, 50 out of the 54 strains of acetic acid bacteria were excluded because of their low aptitude to grow in the tested conditions. The best vinegar was produced from citrus wine at pH 2.90 using the Acetobacter aceti strain DSM_3508T as microbial starter. This research has demonstrated—for the first time—the possibility to produce citrus vinegar at high content of brutieridin and melitidin and other bioactive compounds using selected microbial starters.

2019 - Exploring K2G30 Genome: A High Bacterial Cellulose Producing Strain in Glucose and Mannitol Based Media [Articolo su rivista]
Gullo, Maria; LA CHINA, Salvatore; Petroni, Giulio; Di Gregorio, Simona; Giudici, Paolo

Demands for renewable and sustainable biopolymers have rapidly increased in the last decades along with environmental issues. In this context, bacterial cellulose, as renewable and biodegradable biopolymer has received considerable attention. Particularly, acetic acid bacteria of the Komagataeibacter xylinus species can produce bacterial cellulose from several carbon sources. To fully exploit metabolic potential of cellulose producing acetic acid bacteria, an understanding of the ability of producing bacterial cellulose from different carbon sources and the characterization of the genes involved in the synthesis is required. Here, K2G30 (UMCC 2756) was studied with respect to bacterial cellulose production in mannitol, xylitol and glucose media. Moreover, the draft genome sequence with a focus on cellulose related genes was produced. A pH reduction and gluconic acid formation was observed in glucose medium which allowed to produce 6.14 ± 0.02 g/L of bacterial cellulose; the highest bacterial cellulose production obtained was in 1.5% (w/v) mannitol medium (8.77 ± 0.04 g/L), while xylitol provided the lowest (1.35 ± 0.05 g/L) yield. Genomic analysis of K2G30 revealed a peculiar gene sets of cellulose synthase; three bcs operons and a fourth copy of bcsAB gene, that encodes the catalytic core of cellulose synthase. These features can explain the high amount of bacterial cellulose produced by K2G30 strain. Results of this study provide valuable information to industrially exploit acetic acid bacteria in producing bacterial cellulose from different carbon sources including vegetable waste feedstocks containing mannitol.

2019 - Preparation and characterization of active chitosan/bacterial cellulose nano-whisker composite film enriched with lauroyl arginate ethyl for food packaging applications - Microbial Diversity 2019 [Abstract in Atti di Convegno]
Haghighi, Hossein; LA CHINA, Salvatore; Gullo, Maria; Pulvirenti, Andrea

Acetic acid bacteria are recognized for their wide range of industrial applications. Recently, applying bacterial cellulose (BC) from acetic acid bacteria as a packaging material has received considerable attention from food packaging industries. This is mainly due to its unique properties such as biocompatibility, biodegradability, water holding capacity and remarkable mechanical properties (1). Active packaging is intended to extend the shelf-life of food products and assure their safety and quality inside the packaging systems. In this context, lauroyl arginate ethyl (LAE) is considered as one of the most effective antimicrobial substances among novel food additives which is also classified as GRAS (generally recognized as safe) by the Food and Drug Administration and the European Food Safety Agency (2). Thus, the main aim of this study was to characterize the microstructural, physical, mechanical and optical properties of chitosan/bacterial cellulose nano-whisker (BCNW) composite film enriched with LAE for potential application as active food packaging. Moreover, antimicrobial activity of this film against four common food bacterial pathogens including Campylobacter jejuni, Escherichia coli, Listeria monocytogenes and Salmonella typhimurium, was investigated.

2019 - Preservation, Characterization and Exploitation of Microbial Biodiversity: The Perspective of the Italian Network of Culture Collections [Articolo su rivista]
De Vero, Luciana; Boniotti, Maria Beatrice; Budroni, Marilena; Buzzini, Pietro; Cassanelli, Stefano; Comunian, Roberta; Gullo, Maria; Logrieco, Antonio F.; Mannazzu, Ilaria; Musumeci, Rosario; Perugini, Iolanda; Perrone, Giancarlo; Pulvirenti, Andrea; Romano, Paolo; Turchetti, Benedetta; Varese, Giovanna Cristina

Microorganisms represent most of the biodiversity of living organisms in every ecological habitat. They have profound effects on the functioning of any ecosystem, and therefore on the health of our planet and of human beings. Moreover, microorganisms are the main protagonists in food, medical and biotech industries, and have several environmental applications. Accordingly, the characterization and preservation of microbial biodiversity are essential not only for the maintenance of natural ecosystems but also for research purposes and biotechnological exploitation. In this context, culture collections (CCs) and microbial biological resource centres (mBRCs) are crucial for the safeguarding and circulation of biological resources, as well as for the progress of life sciences. This review deals with the expertise and services of CCs, in particular concerning preservation and characterization of microbial resources, by pointing to the advanced approaches applied to investigate a huge reservoir of microorganisms. Data sharing and web services as well as the tight interconnection between CCs and the biotechnological industry are highlighted. In addition, guidelines and regulations related to quality management systems (QMSs), biosafety and biosecurity issues are discussed according to the perspectives of CCs and mBRCs.

2018 - Biotechnological production of cellulose by acetic acid bacteria: current state and perspectives [Articolo su rivista]
Gullo, M; LA CHINA, Salvatore; Falcone, Pm; Giudici, P

Bacterial cellulose is an attractive biopolymer for a number of applications including food, biomedical, cosmetics, and engineering fields. In addition to renewability and biodegradability, its unique structure and properties such as chemical purity, nanoscale fibrous 3D network, high water-holding capacity, high degree of polymerization, high crystallinity index, light transparency, biocompatibility, and mechanical features offer several advantages when it is used as native polymer or in composite materials. Structure and properties play a functional role in both the biofilm life cycle and biotechnological applications. Among all the cellulose-producing bacteria, acetic acid bacteria of the Komagataeibacter xylinus species play the most important role because they are considered the highest producers. Bacterial cellulose from acetic acid bacteria is widely investigated as native and modified biopolymer in functionalized materials, as well as in terms of differences arising from the static or submerged production system. In this paper, the huge amount of knowledge on basic and applied aspects of bacterial cellulose is reviewed to the aim to provide a comprehensive viewpoint on the intriguing interplay between the biological machinery of synthesis, the native structure, and the factors determining its nanostructure and applications. Since in acetic acid bacteria biofilm and cellulose production are two main phenotypes with industrial impact, new insights into biofilm production are provided.

2018 - La produzione industriale dell’aceto: colture indigene e selezionate [Articolo su rivista]
Zanichelli, G.; Giannone, A.; Gullo, M.

acetiera è la fermentazione in sommerso che viene impiegata per la fermentazione di differenti substrati alcolici, come vino, sidro ed etanolo diluito. Attualmente, il processo di acetificazione è condotto con l’impiego di colture miste di batteri acetici che vengono riutilizzate per l’avvio dei cicli di fermentazione successivi. L’impiego di colture starter selezionate, oltre ad indubbi vantaggi finalizzati all’aumento di resa e produttività, offrirebbe la possibilità di sfruttare caratteri specifici come la termotolleranza, la resistenza ad alte concentrazioni di acido acetico e l’assenza della produzione di cellulosa, considerati tratti di grande interesse per l’industria dell’aceto. In questo lavoro si analizzano le principali criticità e potenzialità della produzione di aceto in sistema sommerso, con particolare riferimento all’impiego di colture starter selezionate.

2018 - Oxidative fermentations and exopolysaccharides production by acetic acid bacteria: a mini review [Articolo su rivista]
LA CHINA, Salvatore; Zanichelli, Gabriele; DE VERO, Luciana; Gullo, Maria

Acetic acid bacteria are versatile organisms converting a number of carbon sources into biomolecules of industrial interest. Such properties, together with the need to limit chemical syntheses in favor of more sustainable biological processes, make acetic acid bacteria appropriate organisms for food, chemical, medical, pharmaceutical and engineering applications. At current, well-established bioprocesses by acetic acid bacteria are those derived from the oxidative pathways that lead to organic acids, ketones and sugar derivates. Whereas emerging applications include biopolymers, such as bacterial cellulose and fructans, which are getting an increasing interest for the biotechnological industry. However, considering the industrial demand of high performing bioprocesses, the production yield of metabolites obtained by acetic acid bacteria, is still not satisfying. In this paper we review the major acetic acid bacteria industrial applications, considering the current status of bioprocesses. We will also describe new biotechnological advances in order to optimize the industrial production, offering also an overview on future directions.

2017 - Applicazioni dei batteri acetici [Altro]
Verzelloni, Elena; Zanichelli, Gabriele; Bonciani, Tommaso; Gullo, Maria

I batteri acetici sono microrganismi aerobi stretti che hanno un uso consolidato nella produzione di aceto. Oltre che per la produzione di aceto sono impiegati per la produzione di molti composti ad alto interesse biotecnologico, come ad esempio intermedi di sintesi della vitamina C (acido 2-cheto- L-gulonico), acidi organici come l’acido gluconico e diidrossiacetone. In tempi recenti è stata sfruttata la loro capacità di produrre cellulosa e ne è stato proposto l’impiego nella produzione di alimenti e bevande prebiotiche grazie alla capacità di produzione di levani esopolisaccaridici. Alla luce di queste evidenze risulta interessante un’analisi di diverse applicazioni industriali dei batteri acetici per evidenziare le potenzialità di sviluppo legate ad aspetti metabolici ancora poco sfruttati.

2017 - Drosophila, efficaci le reti ma servono soluzioni più convenienti [Articolo su rivista]
Caruso, Stefano; Vaccari, Giacomo; Lugli, Stefano; Bellelli, Sara; Francati, Santolo; Maistrello, Lara; Gullo, Maria; Civolani, Stefano; Cassanelli, Stefano

In attesa di individuare tecniche di controllo biologico e biotecnologico efficacemente integrate con la difesa chimica, le reti multifunzionali rappresentano un sistema collaudato e trasferibile alla produzione, ancorché molto oneroso, di non semplice gestione e talora non idoneo per il ceraseto dal punto di vista microclimatico. Tante attività sperimentali in corso, ma, come al solito, manca a livello nazionale un coordinamento strutturato, non volontario, fatto di attività progettuali integrate.

2017 - Increased production of bacterial cellulose as starting point for scaled-up applications [Articolo su rivista]
Gullo, Maria; Sola, Antonella; Zanichelli, Gabriele; Montorsi, Monia; Messori, Massimo; Giudici, Paolo

Bacterial cellulose is composed of an ultrafine nanofiber network and well-ordered structure; therefore, it offers several advantages when used as native polymer or in composite systems. In this study, a pool of 34 acetic acid bacteria strains belonging to Komagataeibacter xylinus were screened for their ability to produce bacterial cellulose. Bacterial cellulose layers of different thickness were observed for all the culture strains. A high-producing strain, which secreted more than 23 g/L of bacterial cellulose on the isolation broth during 10 days of static cultivation, was selected and tested in optimized culture conditions. In static conditions, the increase of cellulose yield and the reduction of by-products such as gluconic acid were observed. Dried bacterial cellulose obtained in the optimized broth was characterized to determine its microstructural, thermal, and mechanical properties. All the findings of this study support the use of bacterial cellulose produced by the selected strain for biomedical and food applications.

2017 - Preservation of Acetic Acid Bacteria [Capitolo/Saggio]
DE VERO, Luciana; Gullo, Maria; Giudici, Paolo

Increased knowledge on physiological, biochemical and genetic properties of acetic acid bacteria (AAB) promotes advancements in biotechnology and innovative fermentation processes. Accordingly, the microbial collections of well-characterized AAB strains are fundamental sources for selecting cultures with desired properties for biotechnological applications. Commonly, culture collections have the fundamental role of safeguarding long-term accessibility of relevant strains by ensuring the maintenance of their ‘authenticity’. Nevertheless, they provide more than just strains, but also essential data, expertise and useful services, which are fundamental for supporting industrial researches.

2017 - Vinegars [Capitolo/Saggio]
Giudici, Paolo; DE VERO, Luciana; Gullo, Maria

The history of fermentation is strictly linked to vinegar production. Among fermented foods, however, vinegar is recognized as a poor product; in many cases, the raw materials have higher nutritional values than the nal product. Vinegar is generally used as a food avoring, a preservative and a beverage with healthy properties. Acetic acid has several uses in the pharmaceutical, cosmetic, chemical and textile industries, where it is produced via chemical synthesis. Vinegar is the product of double scalar fermentation, which is performed by yeasts and acetic acid bacteria (AAB) from sources of fermentable carbohydrates, such as apples, pears, grape, honey, sap of plants, cereals and hydrolyzed starch. In addition, distilled ethanol from fermented raw materials can be used to produce vinegar. In the latter case, vinegar is referred to as ‘spirit vinegar’ or ‘white vinegar’; its use is widespread in northern Europe and the Americas. In some countries, vinegar is also produced from acetic acid via wood pyrolysis; however, this practice is less common, as the fermentation of agricultural raw material is a priority for international organizations, such as the Food and Agriculture Organization (FAO), the World Health Organization (WHO), the European Union (EU) and countries that engage in sustainable production.

2016 - Feasible acetic acid fermentations of alcoholic and sugary substrates in combined operation mode [Articolo su rivista]
Gullo, Maria; Zanichelli, Gabriele; Verzelloni, Elena; Lemmetti, Federico; Giudici, Paolo

Starting from small-scale batch cultivations, acetic acid fermentations in static and submerged systems have been performed by a single acetic acid bacterial strain. To provide user-friendly selected starter cultures for industry, the versatility of these cultures in using different oxidation substrates under different conditions was assessed. In all cases, vinegars with the desired acetic acid, residual ethanol and reducing sugar contents were obtained. An appropriate small-scale batch cultivation subjected to strict process control was pivotal for obtaining the desired acetic acid concentrations and an active culture for submerged fermentation. This achievement enabled the generation of selected starter cultures for submerged vinegar production, which reached an acetic acid content of 8.00–9.00% (w/v), as well as prototype-scale vinegar production. The production of vinegars with reducing sugars in the range of 15.00–27.00 (% w/v) was achieved, and cellulose production was avoided. The dominance of the microbial culture in this process was shown via (GTG)5-PCR. These results are valuable for introducing the use of selected acetic acid bacteria cultures in industrial vinegar production.

2016 - Fermentation strategy to produce high gluconate vinegar [Articolo su rivista]
Giudici, Paolo; DE VERO, Luciana; Gullo, Maria; Solieri, Lisa; Lemmetti, Federico

Gluconic acid is a non-volatile acid that has many applications in food, pharmaceutical and cleaning fields. Gluconic acid has been detected as main oxidation product of Acetobacter and Gluconobacter strains growing on grape must, and it plays an important role in Traditional Balsamic Vinegar. Commonly, high gluconate vinegars have a greater physical stability and a greater preference by consumers because are perceived less pungent. In fact, gluconic acid reduces the pH and increases fixed acidity of the vinegar without increasing the sensation of pungency typical of acetic acid. Its taste is acid but mild sweet and, therefore, gluconic acid has influence on the sensory complexity of the vinegar. The aim of this work is to set up a fermentation procedure that improves the quality of balsamic vinegar by using selected yeasts and acetic acid bacteria strains able to oxidize glucose in grape must-based media having a different sugars concentration. In particular, Saccharomycodes ludwigii UMCC 297 and Acetobacter pasteurianus UMCC 1754 strains were chosen as selected starter cultures for small-scale fermentation of cooked grape must, to evaluate the physical-chemical parameters affecting gluconic acid production in the obtained vinegar. The strains used and the control of all production process have been fundamental for obtaining the vinegar with the desired characteristics.

2015 - Acetic Acid Bacteria of Unimore Microbial Culture Collection: from strains preservation to selected starter cultures distribution [Abstract in Atti di Convegno]
DE VERO, Luciana; Gullo, Maria; Giudici, Paolo

Increased knowledge on physiological, biochemical and genetic properties of acetic acid bacteria (AAB) is driving advancements in biotechnology and innovative fermentation processes. AAB scalable fermentations require robust strains able to maintain their functional traits over processes and to dominate unsterile environments. Accordingly, microbial collections of well-characterized AAB strains are fundamental sources to select cultures with desired properties for biotechnological applications. The University of Modena and Reggio Emilia Microbial Culture Collection (UMCC), specialised in the selection of functional microorganisms for both academic and industrial purposes, holds several AAB strains collected from must, wine, vinegars and kombucha tea. Selective strain isolation, molecular typing, polyphasic identification, and technological selection are the core of UMCC activity finalized to build up appropriate AAB starters for different industrial needs. Shift from preservation status to active AAB cultures is optimised to maintain high cell viability and to reduce genetic drift or strain instability. Technological screening of strains, design and development of selected starters at pilot scale, in static and submerged conditions, are performed to provide industrial cultures for vinegar production. Moreover, consumer demand for high added-value products, including fermented and low sour beverages indicates potential applications for novel and functional starter cultures. UMCC strain information is managed by the BioloMICS NET software (BioAware/, which acts as a comprehensive platform able to combine phenotypic and molecular traits with industrial strain performance.

2015 - Acetic acid bacteria from Unimore microbial culture collection: biolomics platform as a tool for their industrial exploitation [Poster]
Gullo, Maria; DE VERO, Luciana; Zanichelli, Gabriele; Giudici, Paolo

Unimore Microbial Culture Collection includes a pool of acetic acid bacteria (AAB) strains collected since 2000. Main isolation sources of the UMCC AAB strains are wine vinegars, balsamic vinegars, cereal vinegars, fermented juices and kombucha tea. During the years, methods to recover representative isolates and preserve phenotypic stability were improved within UMCC, in order to investigate the key traits useful for their industrial exploitation. Acetic acid bacteria have attractive features useful in performing conventional and innovative processes/products. They incompletely oxidize sugars, alcohols and polyols to the corresponding oxidation products and they are exploited by pharmaceutical, medical, chemical and food-grade industries for the production of acetic acid, dihydroxyacetone, gluconic acid, 2-keto-L-gulonic acid and cellulose. Phenotypic changes, mainly regarding ethanol oxidation, acetic acid resistance and cellulose production, have been detected, consequently, suitable preservation methods and check procedures are performed in UMCC. The AAB strains are identified and characterized by a polyphasic approach and molecular typing are performed by fingerprinting techniques (ERIC/PCR and GTG5). Target strain performance and fermentation assays are developed at pilot scale to provide industrial strains. The BioloMICS (BioAware) platform of UMCC allows a comprehensive data management that combines phenotypic and molecular traits with industrial strain performance.

2015 - An integrated approach to achieve environmentally sustainable control of the new emerging pest Drosophila suzukii in cherry orchards of Emilia Romagna [Poster]
Civolani, S.; Cassanelli, Stefano; Dindo, M.; Fano, E.; Francati, S.; Gullo, Maria; Maini, S.; Maistrello, Lara; Marchetti, E.; Lugli, S.; Vaccari, Giacomo; Caruso, S.

An integrated approach is presented in this study for achieving environmentally sustainable control of Spotted Wing Drosophila (SWD), Drosophila suzukii, in cherry orchards of the Emilia-Romagna region. Analysis was conducted on the response of SWD based on a variety of control strategies and techniques in laboratory and field conditions. The mechanical control considered the use of net covers to avoid pest infestation. Field monitoring was performed to investigate SWD flight patterns and infestations. The biological control of the pest considered the use of native natural enemies predators and parasitoids). Entomo-pathogenic microorganisms were also investigated in the context of microbiological control. The aim is to enhance SWD self-infection using a ‘catch and release’ traps, which attract the adults by means of appropriate chemical and physical stimuli, exposing them to entomo-pathogenic microorganisms. Finally, toxicological (LC50 and LC90) and enzymatic bioassays were performed using different insecticides on different populations to assess SWD resistance. The results of the study will be useful for a better control of this invasive insect following integrated pest management and protecting native beneficial insects.

2015 - I balsamici: fermentazione acetica, viscosità e parametri sensoriali [Monografia/Trattato scientifico]
De Vero, Luciana; Giudici, Paolo; Gullo, Maria; Lemmetti, Federico; Mazza, Stefano

La produzione di aceto di vino è un processo che utilizza materie prime dal valore relativamente basso per ottenere un prodotto che raggiunge prezzi relativamente alti. La categoria merceologica che maggiormente beneficia dell’uso di questi prodotti “poveri” è quella relativa ai condimenti alimentari agrodolci a base di mosto concentrato e/o cotto e aceto di vino, cioè tutti i prodotti che hanno un esplicito riferimento al termine “balsamico”. Indubbiamente la diffusione di prodotti balsamici sul mercato è in forte crescita, anche grazie allo sviluppo di nuove forme di presentazione e di utilizzo del prodotto base (come glasse, creme, spume, spray) e una continua ricerca dell’aromatizzazione distintiva e particolare (attraverso l’utilizzo di fragranze o seguendo processi di produzione peculiari). Nelle province di Modena e Reggio Emilia è concentrata l’intera produzione di aceti “balsamici” a denominazione protetta italiani: due DOP per l’aceto balsamico tradizionale di Modena (ABTM) e quello di Reggio Emilia (ABTRE) e una IGP per l’aceto balsamico di Modena (ABM). L’ABT non è aceto di vino bensì di mosto cotto, tuttavia nell’ABM l’acidità deriva dal comune aceto di vino ottenuto per fermentazione in sommerso. La linea di prodotti sviluppati coniuga gli aspetti migliori dal punto di vista qualitativo ed economico delle due tipologie, introducendo numerose innovazioni: i) le fermentazioni dirette e in condizioni statiche consentono un risparmio energetico notevole e favoriscono la formazione di composti secondari sensorialmente positivi, anche grazie all’impiego di lieviti e batteri acetici specifici e selezionati appositamente per le loro caratteristiche fermentative; ii) il processo di concentrazione del mosto tramite cottura è assente o fortemente limitato mentre l’invecchiamento è accelerato tramite l’utilizzo di tecniche di condizionamento ambientale ecosostenibile; iii) non sono presenti additivi e conservanti di nessun genere in quanto vengono impiegate tecniche di conservazione basate sull’impiego oculato degli stessi microrganismi usati nelle fermentazioni; iv) le condizioni di cottura applicate limitano al minimo la formazioni di composti tossici.

2014 - Aerobic submerged fermentation by acetic acid bacteria for vinegar production: process and biotechnological aspects [Articolo su rivista]
Gullo, Maria; Verzelloni, Elena; Canonico, Matteo

Strictly aerobic acetic acid bacteria (AAB) have a long history of use in fermentation processes, and the conversion of ethanol to acetic acid for the production of vinegar is the most well-known application. At the industrial scale, vinegar is mainly produced by submerged fermentation, which refers to an aerobic process in which the ethanol in beverages such as spirits, wine or cider is oxidized to acetic acid by AAB. Submerged fermentation requires robust AAB strains that are able to oxidize ethanol under selective conditions to produce high-titer acetic acid. Currently submerged fermentation is conducted by unselected AAB cultures, which are derived from previous acetification stocks and maintained by repeated cultivation cycles. In this work, submerged fermentation for vinegar production is discussed with regard to advances in process optimization and parameters (oxygen availability, acetic acid content and temperature) that influence AAB activity. Furthermore, the potential impact arising from the use of selected AAB is described. Overcoming the acetification constraints is a main goal in order to facilitate innovation in submerged fermentation and to create new industry-challenging perspectives.

2014 - Bacterial Community Characterization in Paper Mill White Water [Articolo su rivista]
C., Chiellini; R., Iannelli; R., Lena; Gullo, Maria; G., Petroni

The paper production process is significantly affected by direct and indirect effects of microorganism proliferation. Microorganisms can be introduced in different steps. Some microorganisms find optimum growth conditions and proliferate along the production process, affecting both the end product quality and the production efficiency. The increasing need to reduce water consumption for economic and environmental reasons has led most paper mills to reuse water through increasingly closed cycles, thus exacerbating the bacterial proliferation problem. In this work, microbial communities in a paper mill located in Italy were characterized using both culture-dependent and independent methods. Fingerprinting molecular analysis and 16S rRNA library construction coupled with bacterial isolation were performed. Results highlighted that the bacterial community composition was spatially homogeneous along the whole process, while it was slightly variable over time. The culture-independent approach confirmed the presence of the main bacterial phyla detected with plate counting, coherently with earlier cultivation studies ( Proteobacteria, Bacteroidetes, and Firmicutes), but with a higher genus diversification than previously observed. Some minor bacterial groups, not detectable by cultivation, were also detected in the aqueous phase. Overall, the population dynamics observed with the double approach led us to hypothesize a possible role of suspended bacteria in the re-formation mechanisms of resistant biofilms.

2014 - I batteri acetici [Capitolo/Saggio]
Gullo, Maria; Giudici, Paolo

I batteri acetici (BA) sono microorganismi aerobi stretti in grado di compiere ossidazioni parziali di un gran numero di carboidrati, rilasciando i corrispondenti metaboliti nel mezzo circostante (acidi organici, aldeidi e chetoni). Sono gram-negativi o gram-variabili, di forma ellissoidale o a bastoncino e possono presentarsi singoli, in coppia o in corte catene. Non sporigeni, mobili (flagelli in posizione polare o peritrica) o immobili, catalasi positivi e ossidasi negativi. Il pH ottimale per la loro crescita è compreso tra 5 e 6.5, ma hanno un intervallo di crescita molto ampio e possono sviluppare anche a valori inferiori a 3, come negli aceti. La temperatura ottimale di crescita varia tra 28 e 30° C, ma sono state riscontrate anche specie termotolleranti, con temperature ottimali comprese tra 35 e 38°C. Inoltre i BA possono produrre pigmenti solubili e differenti tipologie di esopolisaccaridi, tra cui la cellulosa. I BA hanno una lunga storia d’uso nei processi alimentari e la maggior parte di essi sono riconosciuti come generalmente sicuri per la salute umana, cioè organismi GRAS (generally recognised as safe). Tuttavia tre specie sono state descritte come patogene umani emergenti: Asaia bogorensis (in un caso di peritonite); Granulibacter bethesdensis (in 3 casi di linfoadenite associata a malattia granulomatosa cronica); e Acetobacter cibinongensis (infezione in paziente dializzato). I BA appartengono all’ordine Rhodospirillales, membri della classe Alphaproteobacteria, all’interno della famiglia Acetobacteraceae. Attualmente sono raggruppati nei seguenti generi: Acetobacter, Acidomonas, Ameyamaea, Asaia, Gluconacetobacter, Gluconobacter, Granulibacter, Komagataebacter, Kozakia, Neoasaia, Neokomagataea, Saccharibacter, Swaminathania e Tanticharoenia.

2013 - Acetic Acid Bacteria: Physiology and Carbon Sources Oxidation [Articolo su rivista]
Mamlouk, Dhouha; Gullo, Maria

Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called “oxidative fermentations”, especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism.

2013 - Acetic acid bacteria: features and impact in bio-applications [Recensione in Rivista]
I., Garcia Garcia; Gullo, Maria

Acetic acid bacteria are a group of microorganisms able to achieve oxidation reactions from sugars and alcohols mainly producing organic acids, aldehydes and ketones. When the substrate is ethanol, acetic acid is produced, thus giving the common name acetic acid bacteria to this bacterial group. Acetic acid bacteria are of considerable importance in food and beverages as beneficial or detrimental bacteria. Nowadays, they play a role as biocatalysts contributing to more eco-friendly bio-based processes, since the production of important industrial molecules generate high environmental impact when chemically synthesized. Although they have a high biotechnological potential, their use at industrial scale is still restricted. The Third International Conference on Acetic Acid Bacteria - Vinegar and Other products, held in Cordoba (Spain), in April 17-20, 2012 ( highlighted several aspects related to acetic acid bacteria in foods, beverages and industrial chemicals production as well as their potential for many new applications.

2012 - Aceto [Capitolo/Saggio]
Giudici, Paolo; Gullo, Maria

La storia delle trasformazioni microbiologiche è strettamente asso-ciata alla produzione di aceto, che è una delle più antiche e può essere fatta risalire a 2000 anni AC. Tuttavia, fra gli alimenti fermentati, l’aceto è sempre stato considerato un prodotto povero, anche perché, in molti casi, le materie prime di partenza sono di maggior valore nutrizionale del prodotto ottenuto. In termini generali l’aceto si presta a molte destinazioni d’uso alimentare, è un aromatizzante, un conservante e, non ultimo, una bevanda alla quale so-no attribuite proprietà salutistiche. Inoltre, l’acido acetico ha impieghi molto diversificati nell’industria farmaceutica, cosmetica, chimica e tessile e viene prodotto sia per sintesi chimica che mediante fermentazione. L’aceto è il risultato di una doppia fermentazione ad opera di lieviti e batteri acetici (BA) in successione scalare, di quasi tutte le fonti di carboidrati fermentescibili: mele, pere, uva, miele, linfa di piante, cereali e amidi idroliz-zati. Anche i distillati alcolici ottenuti da materie prime agricole fermentate sono impiegati per produrre aceto. In quest’ultimo caso l’aceto prende il no-me di “aceto di spirito” o “white vinegar” ed è diffuso in nord Europa e nelle Americhe. In alcuni paesi per fare aceto, viene usato acido acetico ottenuto direttamente dalla pirolisi del legno, ma è bene precisare che è una pratica in estinzione e le organizzazioni internazionali FAO, WHO, Unione Europea e la maggior parte dei paesi riservano all’uso alimentare prodotti ottenuti e-sclusivamente da materie prime agricole idonee, contenenti amidi e/o zuccheri con un processo di doppia fermentazione, prima alcolica e poi acetica.

2012 - Acetobacter pasteurianus strain AB0220: cultivability andphenotypic stability over 9 years of preservation [Articolo su rivista]
Gullo, Maria; Mamlouk, Dhouha; De Vero, Luciana; Giudici, Paolo

Acetobacter species are members of the a-subclassof Proteobacteria, which harbors a large number of bacteriarecalcitrant to cultivation. Strain AB0220 was isolatedfrom a superficial acetification system and preserved for9 years by short and long time methods. Under short timepreservation it was estimated that 540.54 number of generationsoccurred, whereas in long time preservation conditionsthe number of generations was 17.40. Ethanoloxidation to acetic acid was stable and confirmed, as wellas acetate assimilation during long time preservation.Cultivability checks showed persistence of phenotypictraits (growth on ethanol and methanol, growth on differentcarbon sources and cellulose production) over the extendedpreservation time. 16S rRNA gene sequences analysisshowed 100 % of similarity with A. pasteurianus (Accessionnumber GQ240636). Stability of subcultures related tothe culture age and subcultures frequency, tested by ERIC/PCR, confirmed the suitability of long term preservationat least over a period of 9 years.

Solieri, Lisa; D., Mamlouk; L., Kallel; Gullo, Maria

In recent years functional foods promoted with healthclaims have attracted increasing attention on the market.Among them kombucha is a fermented beverage widelyconsumed in Eastern Asian countries, but little is knownabout its constituent microbial communities. In this studytwo 12 days benchmark kombucha fermentations fromgreen and black tea were carried out. A culture-dependentapproach was applied both on exopolysaccharidic andliquid phases to monitor dynamics and diversity of aceticacid bacteria (AAB) and yeasts community. Among AABone main profile was observed (86% of strains); remainingstrains were grouped in 4 profiles by 16S/RFLPbasedanalysis. Whereas by (GTG)5/PCR typing sixteenclusters were obtained. 16S rRNA gene sequencing confirmedthe occurrence of Gluconacetobacter xylinus as predominantboth in green and black samples at 0, 6 and 12days of fermentation. Mainly on ACB medium minor bacterialgroups often colonizating tea leaves (Paenibacillusspp.), plants (Plantibacter spp.) and moisturing environments(Williamsia spp.), were detected starting from 6thfermentation day. Yeast population consisted of a restrictednumber of dominant species: Dekkera sp., Schizo -saccharomyces sp., Zygosaccharomyces sp., Dekkera sp.and Pichia sp. D. anomala was prevailing in both phasesthough all black and green kombucha fermentation times.Sc. pombe was detected only within 6 days of both greenand black tea and it was not isolated after 9 days, when the high ethanol-producing species D. bruxellensis was detected.Z. bailii was isolated from exopolysaccharidic ofblack tea from 6 to 12 days. Finally P. membranifacienswas detected occasionally at the end of the fermentativeprocess. For each species the degree of diversity wasdetermined by combined M13 and OPA20-based RAPDmethod. Cluster analysis showed that one to two prevailingbiotypes occurred through all the process.

2012 - Editorial Board [Direzione o Responsabilità Riviste]
Gullo, Maria

Gullo, Maria

Metabolic potential of acetic acid bacteria (AAB) is ofgreat interest for several fields of the bio-industry.Acetobacter pasteurianus species accounts strains relevantfor the production of both conventional and innovativefermented beverages. Strain AB0220 was isolated in2002 during a large spectrum of isolation work aimed tobuild up an AAB collection from superficial vinegar acetificationsystems. It was preserved for 9 years by shortand long time methods. Ethanol oxidation to acetic acidwas stable and confirmed, as well as acetate assimilationduring preservation. The strain do not produced cellulose.Cultivability checks showed persistence of phenotypictraits over the extended preservation time. Stability ofsubcultures related to the culture age and subcultures frequencyconfirmed the suitability of preservation at leastover a period of 9 years. Strain performance during superficialacetification, both in laboratory and industrial scale,was assayed. To this aim, the acetification ability wastested on different carbon sources and conditions mimingthe basic unit operation of superficial acetification technology.The performance of AB0220 during processeswas evaluated implementing a molecular and analyticalcontrol system. Under the experimental conditions, aceticacid, ethanol and pH were the main parameters dictatingthe conduction of scaling-up procedure. When fixingethanol content between 1 and 3% as upper and lowerlimits and 3% as the lower limit for acetic acid, suitableacidity (6-7%) was reached. The persistence of AB0220as starter over the time was evaluated after biofilm-enrichmentcultures on GYC plates. The biofilm, totally recoveredfrom plates, was processed for genomic DNAextraction. PCR/DGGE and ERIC/PCR were successfullyused to assess species and strain persistence respectively,during 178 days of acetification.

2012 - I campioni del Palio Matildico e gli indicatori di qualità dell'aceto balsamico tradizionale [Esposizione]
Giudici, Paolo; Gullo, Maria; Lemmetti, Federico

La valorizzazione e la tutela dell’Aceto Balsamico Tradizionale, al pari di qualsiasi altro prodotto alimentare tradizionale, non può prescindere dalla conoscenza delle ragioni che lo rendono così specifico e particolare. La ricerca scientifica, oltre ad essere lo strumento di conoscenza necessario alla comprensione della complessità dell’ABT, è anche veicolo di promozione, nel rispetto della chiarezza, dell’autenticità e dell’oggettività, senza ricorrere a spiegazioni fantasiose, che nulla hanno a che fare con la concretezza dell’ABT, frutto dell’acquisizione empirica della conoscenza.

L., Kallel; Gullo, Maria; M., Hamdi

Kombucha or Tea fungus is a traditional fermented beverageobtained during sweetened tea fermentation conductedby acetic acid bacteria (AAB) and yeasts. Historically,Kombucha appeared first in Asia and thereafter its usesand consumption spread from Russia, central Europe andthen over the world. It is composed of a cellulose floatingpellicle and a sour slightly and sparkling broth. However,in spite of vinegar, kombucha remained not well exploredmainly as a niche of AAB strains exploitable in biotechnologicalapplications. The aim of this study was to overviewthe occurrence of AAB in kombucha samples fromliquid and pellicle phases. Kombucha from black andgreen tea was obtained by inoculating a previously grownculture into a freshly prepared tea infusion containing10% of sucrose, 3% (w/v) of cellulose pellicle and 10%(v/v) of broth and led to fermentation up to 15 days in abatch system under aerobic condition. Titrable acidity reacheda maximum of 12 g/L at the end of fermentation inblack kombucha and 6 g/L in green one. pH dropped fromapproximately 3.7 until 2.75 for both samples as a resultof acids formation. Maximum ethanol accumulated at theday 15 did not exceed 0.5% (v/v) for both samples.Cellulose layer become thicker during fermentation, startingfrom 2-3 mm until 10 mm. AAB strains were isolatedfrom pellicle and liquid phases by sampling each 3 daysusing GYC and ACBS media. A total of 93 strains werecollecting during 15 days of fermentation of which 50 arecellulose producing. The majority of strains were tolerantto 5% (v/v) of ethanol and to 30% (w/v) of glucose. Thiswork opens an issue to explore the diversity of AAB fromKombucha focusing their ability to produce cellulose andto grow in low-acidic and sugary environment.

2012 - No-culture strategy for tracking AAB and yeasts in low-acidic and high polyphenolic niches [Abstract in Rivista]
Mamlouk, Dhouha; Solieri, Lisa; Gullo, Maria

Community of acetic acid bacteria (AAB) and yeasts inhabitslow acidic and high polyphenolic niches such as fermentedbeverages. In this work, we selected kombucha asmodel to optimize a no-culture strategy for tracking thedynamics of AAB and yeasts. The strategy consisted of: i)Genomic DNA extraction optimization, ii) PCR/DGGEsetup and iii) Validation of the assay. For gDNA extractionoptimization, we evaluated the suitability of the followinggDNA preparations for a standard PCR-DGGE assay: 1)CTAB/AAB; 2) CTAB/vinegar; 3) Freeze/bead/CTAB1; 4)Freeze/bead/CTAB2 methods. Different extraction methodsaffected not only the quantity and purity of DNA but alsothe complexity of PCR/DGGE profiling. Method 4 allowedus to obtain suitable DNA for PCR assays, as well as thehighest level of complexity in PCR/DGGE band patternsboth for AAB and yeasts. Moreover changes from exopolysaccharidicto liquid phases did not affect the suitability ofthis method. PCR/DGGE setup was performed consideringthe following variables: DNA template concentration, PCRconditions and specificity, effect of GC-clamp and nestedPCR. For AAB, primers pair WBAC1/WBAC2 enabled tostudy AAB dynamics as well other bacterial groups, whereas341f/518r permitted the detection of members of theGluconacetobacter genus. For yeasts, primers pair U1/U2was more efficient then NL1/LS2 in community profiling ofthe majority of kombucha samples. GC-clamp added toforward primers negatively affected gDNA suitability and anested re-PCR for yeasts and AAB was required. Finally,validation of the assay was carried out during kombuchafermentation following AAB and yeasts dynamics from theinoculum to 12 days of incubation. Within AAB species,Gluconacetobacter xylinus responsible for the exopolysaccharidicnetwork matrix, was mainly detected, whereasZygosaccharomyces spp, Dekkera spp, Pichia spp andSchizosaccharomyces pombe in the case of yeasts.

2012 - Oxidation of sugars and polyalcohols by acetic acid bacteria during surface culture fermentation [Abstract in Rivista]
Giudici, Paolo; Gullo, Maria; DE VERO, Luciana

Acetic Acid Bacteria (AAB) are well known for their ability to oxidize alcohols, aldehydes, sugars, polyalcohols and others molecules with ketonic or aldehydic functional groups. Species of Acetobacter and Gluconobacter lack a functional Embden-Meyerhof-Parnas pathway and are unable to metabolize hexose sugars by this route. Hexose and pentose sugars are oxidatively metabolized by the hexose monophosphate pathway to acetic and lactic acids. In some cases, hexose sugars may be directly oxidized to gluconate and ketogluconates without further catabolism, leading to an accumulation of these end products in the culture medium. Furthermore, Gluconobacter oxydans has been used to oxidize various sugars and sugar alcohols to substances of industrial significance, such as sorbose, gluconic acid and ketogluconic acids. Dihydroxyacetone, 2,3-butanediol, and acetoin are also significant products of carbohydrate metabolism evolved by AAB Our trials of surface static fermentation was carried out on complex media such as base wine (BW) for Traditional Balsamic Vinegar, where sugars and alcohols are present in different amount. In this conditions AAB sequentially oxidized the several carbon sources, first ethanol, then glucose and glycerol. In particular the oxidation of glucose to gluconate occurred when the ethanol was exhausted, then high amount of gluconate was accumulated in the medium. BW had an initial composition of around 7% (v/v) of ethanol and 25% of sugars with glucose and fructose in the ratio 1/1. At the end of the fermentation the glucose/fructose ratio was in favour of fructose, titratable acidity was very high due to the gluconate formed, while volatile acidity decreased. In summary, when surface fermentation is extended afterward the ethanol run out, other substrates are oxidized and give origin to a vinegar with a completely different composition. The extension of the oxidative step is a tool for increasing vinegar’s sweetness and acidity without the acetic acid sensorial pungency. (empty line)Keywords: gluconic acid, sugar oxidation, surface static acetification.

2012 - Traditional balsamic vinegar: a microbiological overview [Capitolo/Saggio]
Solieri, Lisa; Gullo, Maria; Giudici, Paolo

Traditional balsamic vinegar: a microbiological overview

2011 - Acetic Acid Bacteria [Direzione o Responsabilità Riviste]
Gullo, Maria

2011 - Evaluation and optimisation of bacterial genomic DNA extraction forno-culture techniques applied to vinegars [Articolo su rivista]
Mamlouk, Dhouha; C., Hidalgo; M. J., Torija; Gullo, Maria

Direct genomic DNA extraction from vinegars was set up and suitability for PCR assaysperformed by PCR/DGGE and sequencing of 16S rRNA gene. The method was tested on 12intermediary products of special vinegars, fruit vinegars and condiments produced from different rawmaterials and procedures. DNAs extraction was performed on pellets by chemical, enzymatic, resinmediated methods and their modifications. Suitable yield and DNA purity were obtained bymodification of a method based on the use of PVP/CTAB to remove polyphenolic components andesopolysaccharides. By sequencing of bands from DGGE gel, Ga. europaeus, A. malorum/cerevisiae andA. orleanensis were detected as main species in samples having more than 4% of acetic acid content.From samples having no acetic acid content, sequences retrieved from excised bands revealed highsimilarity with prokaryotes with no function on vinegar fermentation: Burkholderia spp, Cupriavidusspp., Lactococcus lactis and Leuconostoc mesenteroides. The method was suitable to be applied for noculturestudy of vinegars containing polyphenols and esopolysaccharides allowing a more completeassessment of vinegar bacteria.

2011 - Traditional Balsamic Vinegar: a microbiological overviw [Capitolo/Saggio]
Solieri, Lisa; Gullo, Maria; Giudici, Paolo

Over time, the name “balsamic vinegar” has acquired an important trade value and is now being usedto generally designate sweet and sour condiments with high viscosity and dark/brown color. Balsamiccondiments could be grouped in four different categories: generic balsamic vinegars, balsamic vinegarwith appellation of origin (PDO and Protected Geographical Indication or PGI), balsamic sauces, anddressing (Giudici et al. 2009). In particular “Balsamic Vinegar of Modena” (BVM) is an industrial classof special vinegar legally recognized since 1965 and recently granted European PGI status (CommissionRegulation EC No 583/2009). Despite their similar appellation, TBV and BVM are very distinct productsdue to different manufacturing technologies and starting materials. BVM is produced by aging a blendof cooked must and wine vinegar with addition of caramel, for a short time (minimum 2 months). Due tothis different technology, BVM cannot duplicate the complexity flavor and the higher viscosity of TBVand it meets consumer’s expectations to buy cheaper vinegar compared to TBV (Giudici et al. 2009a).This chapter aims to describe the main technological and microbiological steps of TBV processing,underlying the role of microbial transformations in determining its quality.

2010 - Acetic Acid Bacteria, Biotechnological Applications [Voce in Dizionario o Enciclopedia]
DE VERO, Luciana; Gullo, Maria; Giudici, Paolo

2010 - Diversity of Acetobacter pasteurianus Strains IsolatedFrom Solid-State Fermentation of Cereal Vinegars [Articolo su rivista]
J., Wu; Gullo, Maria; F., Chen; Giudici, Paolo

Vinegar production is based on the acetificationprocess by indigenous acetic acid bacteria (AAB). Amongvinegar technologies, solid-state fermentation (SSF) processesare widespread in Asian countries to produce vinegarat small-scale. In this study, 21 AAB strains isolatedfrom Chinese cereal vinegars produced by SSF collected indifferent regions of China were characterized by enterobacterialrepetitive intergenic consensus (ERIC)–PCR fingerprinting.Isolates exhibited high degree of phenotypicvariability as well as suitable traits for their uses as selectedstrains in SSF vinegar production (growth modality bysuperficial biofilm, no production of cellulose, ability togrowth on ethanol media). 16S rRNA gene sequencinganalysis of representative strains showed that strains ofAcetobacter pasteurianus have a close association to cerealvinegars, whereas Gluconacetobacter europaeus populationis not favoured. Selection of single or multiple strainsculture within A. pasteurianus species was predicted inview of their application in SSF technology. This seems tobe the first report showing phenotypic and genetic variabilityof AAB strains involved in SSF processes. Resultscan be exploited for the implementation of large-scale SSFprocesses by selected strains for vinegar production andother innovative biotechnological applications.

2010 - I microrganismi del balsamico ed aspetti della qualità [Esposizione]
Giudici, Paolo; Gullo, Maria; DE VERO, Luciana; F., Lemmetti; U., Rangone

Il convegno tratta gli aspetti della scalarità del proceso fermentativo: fermentazione alcolica ed aciteca, con particolare attenzione alla resa del processo ed agli aspetti qualitativi.

2009 - Acetic Acid Bacteria Taxonomy from Early Descriptions to Molecular Techniques [Capitolo/Saggio]
Gullo, Maria; Giudici, Paolo

The exploitation of acetic acid bacteria (AAB) has a long history in fermentation processes and now represents an emerging field in biotechnological applications, especially with regard to the biosynthesis of useful chemicals with a potentially high economic value and, in food science, through the standardization of micro- biological processes for the manufacture of both vinegar and other fermented beverages. Historically, AAB were recognized as ‘vinegar bacteria’ because the first stud- ies were done on vinegar, and later on wine and beer spoilage. In fact, vinegar AAB are a subset of a larger AAB group, which includes bacteria that interact with flowers, fruits, the rhizosphere of plants, and even human beings (Table 3.1). It is generally recognized that AAB are fastidious microorganisms, which means that many of them are difficult to grow on laboratory media. Many efforts have been made to isolate and culture colonies of AAB. Several media have been suggested and tried, but none of them appears to satisfy the growth requirements of AAB. This has hindered the application of cultivation-based techniques to the study of AAB and, consequently, their taxonomic classification. However, the recent dis- covery of new culture-independent methods has opened up new horizons for the systematic study of AAB.

2009 - Succession of Selected Strains of Acetobacter pasteurianus and Other Acetic Acid Bacteria in Traditional Balsamic Vinegar [Articolo su rivista]
Gullo, Maria; DE VERO, Luciana; Giudici, Paolo

The application of a selected Acetobacter pasteurianus strain for traditional balsamic vinegar production was assessed. Genomic DNA was extracted from biofilms after enrichment cultures on GYC medium (10% glucose, 1.0% yeast extract, 2.0% calcium carbonate) and used for PCR/denaturing gradient gel electrophoresis, 16S rRNA gene sequencing, and enterobacterial repetitive intergenic consensus/PCR sequencing. Results suggested that double-culture fermentation is suitable for traditional balsamic vinegar acetification.

2009 - Technological and Microbiological Aspects of Traditional Balsamic Vinegar and Their Influence on Quality and Sensorial Properties [Capitolo/Saggio]
Giudici, Paolo; Gullo, Maria; Solieri, Lisa; Falcone, Pasquale Massimiliano

The term “balsamic” is widespread and popular all over the world of vinegar and fancy foods; it is used generally to refer to vinegars and sauces with a sweet and sour taste. However, the original is the European Protected Denomination, registered as “Aceto Balsamico Tradizionale of Modena, or of Reggio Emilia” that should not be confused with the “Aceto Balsamico di Modena” very similar in the name, but completely different for technology, raw material, quality, and sensorial properties. Traditional balsamic vinegar is made by a peculiar procedure, that starts with a thermal concentration of freshly squeezed grape juice, followed by alcoholic and acetic fermentations and, finally, long aging in a wooden barrel set, by a procedure which requires a partial transfer of vinegar from cask to cask with the consequential blending of vinegars of different ages. In addition, water transfer occurs across the wood of the barrels, the result being an increase of solute concentration of the vinegar. The chemical and physical transformations of the vinegar are mainly directed by the low water activity of the vinegar. High-molecular polymeric compounds are the main and characteristic constituents of original and old traditional balsamic vinegar, and the major cause of its rheological and sensorial properties.

2009 - Traditional balsamic vinegar [Capitolo/Saggio]
Giudici, Paolo; Gullo, Maria; Solieri, Lisa

The term ‘balsamic vinegar’ is frequently applied to describe sauces, condiments and dressings with particular sweet taste. In Italy there are two types of balsamic vinegar: ‘balsamic vinegar of Modena’ and ‘traditional balsamic vinegar’. The first is a flavoured wine vinegar obtained by blending cooked must and wine vinegar and, in some cases, by adding a small amount of caramel. Traditional balsamic vinegar (TBV) is made in Modena and Reggio Emilia with cooked grape must, through a three-step process: conversion of sugars to ethanol by yeasts; oxidation of ethanol to acetic acid by acetic acid bacteria (AAB); and, finally, at least 12 years of ageing. The final product is a highly dense, dark-brown aged vinegar, having a sweet and sour taste, fruity and complex in flavour.

2008 - Acetic acid bacteria in traditional balsamic vinegar: Phenotypic traits relevant for starter cultures selection [Articolo su rivista]
Gullo, Maria; Giudici, Paolo

This review focuses on acetic acid bacteria in traditional balsamic vinegar process. Although several studies are available on acetic acid bacteria ecology, metabolism and nutritional requirements, their activity as well as their technological traits in homemade vinegars as traditional balsamic vinegar is not well known. The basic technology to oxidise cooked grape must to produce traditional balsamic vinegar is performed by the so called “seed-vinegar” that is a microbiologically undefined starter culture obtained from spontaneous acetification of previous raw material.Selected starter cultures are the main technological improvement in order to innovate traditional balsamic vinegar production but until now they are rarely applied. To develop acetic acid bacteria starter cultures, selection criteria have to take in account composition of raw material, acetic acidbacteria metabolic activities, applied technology and desired characteristics of the final product. For traditional balsamic vinegar, significative phenotypical traits of acetic acid bacteria have been highlighted. Basic traits are: ethanol preferred and efficient oxidation, fast rate of acetic acid production, tolerance to high concentration of acetic acid, no overoxidation and low pH resistance. Specific traits are tolerance to high sugar concentration and to a wide temperature range. Gluconacetobacter europaeus and Acetobacter malorum strains can be evaluated to develop selected starter cultures since they show one or more suitable characters.

2008 - Applicazione della tecnica rDNA PCR-DGGE nello studio della popolazione lattica dominante in parmigiano reggiano [Articolo su rivista]
Solieri, Lisa; E., Gala; Gullo, Maria; Giudici, Paolo

Applicazione della tecnica rDNA PCR-DGGE nello studio della popolazione lattica in parmigiano reggiano.

2008 - Improvement of traditional vinegar production by selected acetic acid bacterium strain: Acetobacter pasteurianus as acetification starter [Poster]
Gullo, Maria; DE VERO, Luciana; Giudici, Paolo

Recent microbiological studies investigated the acetic acid bacteria microflora of traditional balsamic vinegar (TBV) highlighting the occurrence of Gluconacetobacter europaeus as widespread indigenous species, followed by Acetobacter pasteurianus, Acetobacter aceti and Acetobacter malorum1,2. However no correlation between occurring species and quality of product have been examined. In this study a selected starter culture (SSC) was designed, implemented at laboratory scale and applied to vinegar factory by scale up procedure. A. pasteurianus strain AB0220 was selected as SSC on the basis of phenotypical and technological traits suitable for TBV must oxidation. The SSC was implemented through three stages: starting steps in laboratory conditions (Stage 1); scale-up performed through a tanks system (Stage 2) and a barrels system (Stage 3) in factory conditions. Main analytical parameters were monitored by pH, titrable acidity, ethanol and soluble solids trend. Moreover molecular identification based on 16S rDNA region analysis (PCR-DGGE and sequencing) and ERIC-PCR were performed respectively to assess species occurrence and evaluate strain persistence during the whole process. In particular the dominant AAB species population was estimated by PCR-DGGE analysis allowing to distinguish two different species groups along the 3 stages. 16S rDNA sequencing confirmed DGGE results, showing high percentage of sequence homology (99 and 100%) with A. pasteurianus at stage 1 and 2 and Ga. europaeus at Stage 3. Finally, ERIC-PCR fingerprinting assay performed at the end of each acetification stage showed an electrophoretic profile similar to that of AB0220 at stage 1 and 2, whereas a different pattern at stage 3. This result supports DGGE data suggesting a change in the population during the 3 acetification stages. On the basis of these evidences, our hypothesis is that the persistence of inoculated strain during stages 1 and 2 was assured by the scale-up procedure. New must was periodically added to increase the SSC volume and microbial population was not exposed to constant effect of acetic acid. Instead, the static conditions of stage 3 resulted in a constant increase of acetic acid concentration, negatively affected AB0220 growth. In this environment, indigenous Ga. europaeus cells, which is less sensitive to physiological stress caused by acetic acid3, found optimal growth conditions to become dominant. In this study for the first a SSC for TBV production was implemented and applied at factory scale. Results demonstrated that selected A. pasteurianus strains are suitable to start the acetification of TBV ensuring the acetification course in unsuitable conditions for other AAB such as Ga. europaeus. On the contrary, Ga. europaeus strains are able to oxidise cooked must in presence of constant of acetic acid concentration corresponding to the final stages of TBV oxidation. Results suggest that the introduction of SSC could be a valid innovation in TBV production, contributing to safety and quality of the product and improving the reliability and stability of technological process.

2008 - Introductory note [to special issue on vinegars and acetic acid bacteria] [Articolo su rivista]
Gullo, Maria; GRAHAM H., Fleet; SARA BOVER, Cid

The exploitation of acetic acid bacteria has a long history infermentation processes and it is now an emerging field inbiotechnological applications, such as biosynthesis of higheconomical relevance molecules, and in food industry, wheremore reliable and controlled microbiological processes forvinegar and other fermented beverages production are required.The metabolic potential of acetic acid bacteria is joined to theirability to partially oxidize carbohydrates releasing the corresponding products (aldehydes, ketones and organic acids) into the medium. Due this feature acetic acid bacteria are knownsince a long time as the main agent of vinegar production butalso as contaminant in other fermented beverages like wine.

2008 - Special Issue "Vinegars and Acetic Acid Bacteria 2005 [Monografia/Trattato scientifico]

acetic acid bacteria, vinegar, biotechnological advances

2007 - Età dell'aceto balsamico ed altri aspetti pratici [Esposizione]
Giudici, Paolo; Gullo, Maria; Falcone, Pasquale Massimiliano

Valutazione dell'età dell'aceto balsamico e gestione della batteria.

2007 - Isolation and cultivation of acetic acid bacteria from high selective sources [Relazione in Atti di Convegno]
Gullo, Maria; Giudici, Paolo

Cultivable acetic acid bacteria (AAB) are used as oxidising bacteria in several biotechnological applications (e.g vitamin C, dihydroxyacetone, gluconate, ketogluconates synthesis) as well as in fermentative processes (vinegar). Troubles about their isolation and cultivation in laboratory media has been well reported. The viable but not cultivable state seems mainly influenced by environmental stress conditions and current isolation methods allow to access only a small subset of AAB population. Also the handling and preservation of strains isolated from high selective sources is still a hard practice. Among vinegars, traditional balsamic vinegar is made through cooking the grape must, in which spontaneous alcoholic fermentation and acetic oxidation take place, then it is aged to be bottled. Cooked grape must is characterized by very low pH and high sugars content. In previous works we observed high selective pressure of cooked grape must on AAB growth and the loss of strains viability under laboratory conditions. Moreover culture independent studies by PCR/DGGE, highlighted that only easier cultivable strains are isolated from cooked grape must by conventional culture-dependent methods. In this study AAB strains were isolated from cooked grape musts by plating system using three isolation media, molecular characterized by PCR/RFLP analysis and partial sequencing of rDNA region. To test the ability to carry out the oxidation process in high selective substrates, cooked grape must, wine and “Passmore and Carr” medium, with different pH, titrable acidity, soluble solids and ethanol content, were used as substrates. The results showed the high soluble solids parameter as the main limiting factor of AAB growth and activity in cooked grape must. Improvement of isolation and cultivation methods could provide recognition of new species, a better preservation system of strains, allowing an AAB strains selection of biotechnological interest.

2006 - Application of denaturing gradient gel electrophoresis (DGGE) analysis to evaluate acetic acid bacteria in traditional balsamic vinegar [Articolo su rivista]
DE VERO, Luciana; Gala, Elisabetta; Gullo, Maria; Solieri, Lisa; Landi, Sara; Giudici, Paolo

Acetic acid bacteria (AAB) are fastidious micro-organisms to isolate and cultivate despite of the great number of growth media available. Moreover, conventional techniques used to study AAB populations are time consuming and not completely reliable. In this study, we tested the usefulness of the polymerase chain reaction-denaturing gradient gel electophoresis (PCR-DGGE) as a rapid and cost effective method for the screening of AAB in traditional balsamic vinegar (TBV). DGGE analysis was applied to 19 AAB strains isolated by agar plating from three different samples of TBV. DGGE was also used for the analysis of PCR products obtained from DNA extracted directly from the TBV samples. A tentative species identification was achieved comparing the PCR-DGGE patterns of the isolated strains and the TBV samples to those of 15 AAB reference strains. The results support that DGGE is functional to monitor vinegar´s AAB population.

2006 - Aspetti microbiologici nella gestione di una batteria di Aceto Balsamico Tradizionale [Articolo su rivista]
DE VERO, Luciana; Gullo, Maria; Gala, Elisabetta; Giudici, Paolo

Il processo di produzione dell’aceto balsamicotradizionale prevede quattro fasi distinte:cottura del mosto, fermentazione alcolica,fermentazione acetica ed invecchiamento.Ognuna di queste fasi va gestita attentamentesulla base di fattori sia di tipo chimicofisicoche microbiologico. Data la scalaritàdelle fasi, le anomalie presenti a monte delprocesso si ripercuotono sul prodotto finale.Ad esempio, le fermentazioni spontaneesono tra le principali cause di variabilità e diinsuccesso ed è per tal motivo che occorreun accurato monitoraggio della batteria chepossa preventivamente correggere eventualiirregolarità nel sistema. In particolare, iparametri da monitorare durante la gestionedella batteria sono: l’acidità titolabile, laconcentrazione alcolica, il pH, la temperaturae l’ossigeno. L’impiego di colture starter dilieviti e batteri acetici selezionate sulla basedei caratteri desiderabili può essere utileper la standardizzazione del processo e perl’ottenimento di un prodotto che presenti leproprietà chimico-organolettiche richieste.

2006 - Characterization of acetic acid bacteria in traditional balsamic vinegar [Articolo su rivista]
Gullo, Maria; C., Caggia; De Vero, Luciana; Giudici, Paolo

This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with concentrated cooked must. On the contrary, ethanol concentration of the cooked and fermented must is less significant for acetic acid bacteria growth. A tentative identification of the isolated strains was done by 16S-23S-5S rDNA PCR/RFLP technique and the isolated strains were clustered: 32 strains belong to Gluconacetobacter xylinus group, two strains to Acetobacter pasteurianus group and one to Acetobacter aceti.

2006 - Detection of Acetic Acid Bacteria in Traditional Balsamic Vinegar by PCR-DGGE analysis [Relazione in Atti di Convegno]
DE VERO, Luciana; Gullo, Maria; Landi, Sara; Giudici, Paolo

The denaturing gradient gel electrophoresis (DGGE) applied to PCR products of relatively conserved regions in the genome is a well documented culture-independent method to study microbial communities. In the present study we used DGGE to evaluate acetic acid bacteria population of Traditional Balsamic Vinegar which is, to our knowledge, a system not investigated with this approach previously. The results obtained suggest that PCR-DGGE is clearly a suitable tool for a rapid and cost effective screening of acetic acid bacteria in vinegar’s samples.

Gullo, Maria; Solieri, Lisa; Giudici, Paolo

Vinegar production as well other fermented foods and beverages is based on the use of starter cultures which permit a higher degree of control and standardisation of the final product compared to spontaneous fermentation. The first task to optimise fermented foods process is the knowledge of microorganism physiological and metabolic traits. Acetic acid bacteria species occurring in vinegar production are well known, but species monitoring and strains selection are not common procedures. Then there are not extensive studies on significant traits of strains involved in vinegar oxidation process. Concerning to traditional balsamic vinegars few researches are available about occurring species and their physiological traits. In this study strains isolated from traditional balsamic vinegar samples were investigated by enzymatic digestion of ITS1 regions using RsaI and HaeIII restriction endonucleases and by sequencing of 16S rDNA and ITS1 rDNA. Since elevated sugar concentration resistance and growing is an important trait for traditional balsamic vinegar acetic acid bacteria, the isolated strains were tested for glucose tolerance. On the basis of technological results glucose concentration is an acetic acid bacteria limiting-factor and Acetobacter malorum species is more resistant to high glucose concentration than other species occurred in balsamic vinegar.Keywords: acetic acid bacteria, glucose tolerance, strains selection

2006 - I Microrganismi dell'aceto balsamico. Atti del convegno: "Anche la tradizione va studiata" Risultati di un biennio di indagini per l'individuazione e il possibile impiego di starter per Aceto Balsamico Tradizionale. [Curatela]
Licciardello, Fabio; Falcone, Pasquale Massimiliano; Tagliazucchi, Davide; Giudici, Paolo; Solieri, Lisa; Gullo, Maria; DE VERO, Luciana

Il ruolo e l'importanza dei microrganismi sulla qualità dell'aceto balsamico tradizionale.

2006 - I microrganismi dell'aceto balsamico. [Esposizione]
Giudici, Paolo; Solieri, Lisa; Gullo, Maria; Pulvirenti, Andrea; DE VERO, Luciana; Falcone, Pasquale Massimiliano

Il processo di produzione dell’aceto balsamico tradizionale prevede quattro fasi distinte: cottura del mosto, fermentazione alcolica, fermentazione acetica ed invecchiamento. Ognuna di queste fasi va gestita attentamente sulla base di fattori sia di tipo chimico-fisico che microbiologico. Data la scalarità delle fasi, le anomalie presenti a monte del processo si ripercuotono sul prodotto finale. Ad esempio, le fermentazioni spontanee sono tra le principali cause di variabilità e di insuccesso ed è per tal motivo che occorre un accurato monitoraggio della batteria che possa preventivamente correggere eventuali irregolarità nel sistema. In particolare, i parametri da monitorare durante la gestione della batteria sono: l’acidità titolabile, la concentrazione alcolica, il pH, la temperatura e l’ossigeno. L’impiego di colture starter di lieviti e batteri acetici selezionate sulla base dei caratteri desiderabili può essere utile per la standardizzazione del processo e per l’ottenimento di un prodotto che presenti le proprietà chimico-organolettiche richieste. L’età dell’aceto balsamico tradizionale è difficile da definire e da calcolare per il particolare modo di produzione: aliquote di aceto sono trasferite annualmente da un barile all’altro. La conduzione delle batterie rende difficoltoso il calcolo dell’età, tuttavia in questo lavoro abbiamo sviluppato un modello algebrico per il calcolo dell’età. In particolare abbiamo definito i limiti di età teoricamente raggiungibili in ogni barile della batteria.

2006 - Isolamento e selezione di batteri acetici per aceto balsamico tradizionale [Articolo su rivista]
Gullo, Maria; Giudici, Paolo

Molti alimenti fermentati vengono preparati mediante l’impiego di colture starter selezionate; i vantaggi che ne derivano sono molteplici e volti ad evitare il rischio di fermentazioni spontanee causate da microrganismi non idonei e a garantire la salubrità del prodotto. Nella produzione di aceto a tutt’oggi non vengono impiegate colture starter selezionate, ma l’avvio dell’acetificazione è indotto da masse precedentemente acidificate. Nel caso dell’aceto balsamico tradizionale, questo sistema non sempre fornisce buoni risultati a causa della difficoltà di sviluppo dei batteri acetici in mezzi molto concentrati come il mosto cotto. L’impiego di colture starter di batteri acetici osmotolleranti rappresentaun’innovazione in grado di rendere il processo riproducibile e costante.

2006 - Le Fermentazioni dell’Aceto Balsamico Tradizionale [Capitolo/Saggio]
Giudici, Paolo; Gullo, Maria; Solieri, Lisa; DE VERO, Luciana; Sara, Landi; Pulvirenti, Andrea; Sandra, Rainieri

Scritto a più mani dall'équipe di ricerca dell'Università di Modena e Reggio Emilia che fa capo al professor Paolo Giudici, il libro presenta al pubblico degli amanti dell'aceto balsamico tradizionale i più recenti risultati delle ricerche svolte in ambito microbiologico nelle varie fasi di produzione di questo straordinario prodotto della nostra tradizione, amato e apprezzato in tutto il mondo. Il professor Giudici in questo volumetto articola con limpida chiarezza divulgativa parte dei risultati conseguiti dalla sua équipe, trasmettendo alcune nozioni necessarie per la conduzione delle fermentazioni. A ciò si aggiunga una sezione di letteratura specialistica particolarmente abbondante e curata sulla microbiologia dell'aceto balsamico.

2006 - Le fermentazioni dell’aceto balsamico tradizionale [Monografia/Trattato scientifico]
Giudici, Paolo; Gullo, Maria; Solieri, Lisa; DE VERO, Luciana; Landi, Sara; Pulvirenti, Andrea; Rainieri, Sandra

Scritto a più mani dall'équipe di ricerca dell'Università di Modena e Reggio Emilia che fa capo al professor Paolo Giudici, il libro presenta al pubblico degli amanti dell'aceto balsamico tradizionale i più recenti risultati delle ricerche svolte in ambito microbiologico nelle varie fasi di produzione di questo straordinario prodotto della nostra tradizione, amato e apprezzato in tutto il mondo. Il professor Giudici in questo volumetto articola con limpida chiarezza divulgativa parte dei risultati conseguiti dalla sua équipe, trasmettendo alcune nozioni necessarie per la conduzione delle fermentazioni. A ciò si aggiunga una sezione di letteratura specialistica particolarmente abbondante e curata sulla microbiologia dell'aceto balsamico.

2005 - Acetic acid bacteria in Traditional Balsamic Vinegar by PCR-DGGE analysis [Relazione in Atti di Convegno]
Gala, Elisabetta; DE VERO, Luciana; Solieri, Lisa; Gullo, Maria

Aims: The greatest limits in the study and selection of acetic acid bacteria are due to the difficultyof isolating and cultivating them. A culture-independent molecular technique, PCR-DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electophoresis), was used in order to study the acetic acid bacteria of Traditional Balsamic Vinegar.Methods and results: Primers WBAC1 and WBAC2 were successfully used with DNA extractedfrom both acetic acid bacteria strains and vinegar’s samples and they gave PCR products that allowed differentiation by DGGE. The results obtained indicate that acetic acid bacteria species involved in spontaneous oxidation process can be represented by only one dominant species.Conclusion: A change in acetic acid bacteria species during fermentation process could be supposed: Ga. xylinus was the main representative species in cooked must while A. pasteurianusbecame more prevalent in vinegar’s samples.Significance and impact of the study: This study clearly indicated that PCR-DGGE is a suitable tool for monitoring TBV microbial population and specifically acetic acid bacteria which are difficult to isolate applying conventional microbiological techniques.

2005 - Acetic acid bacteria of traditional balsamic vinegar. [Relazione in Atti di Convegno]
DE VERO, Luciana; Gullo, Maria; Landi, Sara; Solieri, Lisa

Aims: Traditional Balsamic Vinegar has been made by the ageing of cooked grape must into wooden barrels arranged in set of 5-7 casks each of varying capacity. Every year a small amount of vinegar is transferred from a bigger to a smaller barrel and new cooked must is added to the first barrel of the set. In this way the sugary concentration is increased from the biggest to the smallest barrel due to water evaporation across the wood.Methods and results: Different molecular techniques were applied to study acetic acid bacteriain Traditional Balsamic Vinegar. In particular 16S-23S-5S rDNA PCR/RFLP analysis, DGGE and sequencing techniques were performed on both acetic acid bacteria type strains and isolated strains from vinegars.Conclusion: Gluconacetobacter xylinus is the main species of Traditional Balsamic Vinegar and the greatest hurdle to the growth of acetic acid bacteria is high sugar concentration.Significance and impact of the study: The results suggest new technological approach to vinegar production.

2005 - Acido succinico quale causa della mancata rifermentazione spontanea in bottiglia del Lambrusco [Articolo su rivista]
S., Landi; Gullo, Maria; DE VERO, Luciana; Ulrici, Alessandro; R., Sidari; Giudici, Paolo

La rifermentazione in bottiglia dei Lambruschiè una pratica consolidata, che conferisce alvino caratteristiche sensoriali apprezzate daiconsumatori. Recentemente, e con sempremaggiore frequenza, è stata osservata la mancatarifermentazione del prodotto in bottiglia. Studipreliminari hanno messo in evidenza che lafrequenza della mancata rifermentazione èmaggiore nei vini imbottigliati precocementee senza aggiunta di lieviti. Inoltre, tutti icampioni esaminati che manifestano mancatarifermentazione contestualmente presentano valoridi acido succinico pari a 3 g/L. Va sempre tenutoconto che la crescita microbica è condizionatanon da un singolo fattore, ma da più fattori,perciò abbiamo allestito delle sperimentazioni chetenessero conto dei parametri più significativi,quali pH, densità di inoculo, concentrazione diacido succinico e concentrazione di etanolo. Unaprova di rifermentazione in bottiglia in condizionidi cantina ha definitivamente confermato la forteazione inibitrice dell’acido succinico sullo sviluppocellulare di Saccharomyces cerevisiae. I risultatisono coerenti con l’ipotesi che l’acido succinico,nell’ambito dei valori di pH e di concentrazionidi inoculo studiati, sia la causa della mancatarifermentazione.The spontaneous secondary alcoholicfermentation of the Lambrusco wine in bottle isa well-established practice that confer it someappreciated sensorial characteristics. Recently, andwith more frequency, it was observed the lack ofspontaneous secondary alcoholic fermentation inbottle. Preliminary studies have put in evidencethat the frequency of this problem is greater inearly bottled wines, produced without the additionof selected yeasts. Moreover, all the samples withthis problem have, at the same time, a succinicacid concentration of 3 g/L. These observationshave allowed the AA. to formulate the hypothesisthat succinic acid, in the presence of other limitingconditions, could be the cause of the lackedspontaneous secondary alcoholic. Since microbialgrowth is influenced by many factors, the AA. haveperformed several experiments considering themost significant parameters: pH, inoculum density,succinic acid content, and ethanol concentration.A secondary alcoholic fermentation test, carriedout under winery conditions, has confirmed thestrong inhibiting action of the succinic acid onSaccharomyces cerevisiae growth. The resultsare consistent with the hypothesis that, for thetested range, succinic acid is the reason of lackedspontaneous secondary alcoholic fermentation ofthe Lambrusco wine in bottle

2005 - Colture starter per la produzione di Aceto Balsamico Tradizionale: aspetti pratici ed applicativi [Articolo su rivista]
Giudici, Paolo; DE VERO, Luciana; Landi, Sara; Gullo, Maria; Solieri, Lisa

I batteri acetici sono un gruppo di microrganismia nicchia molto specializzata, difficili da coltivaree mantenere in coltura pura. I batteri acetici daimpiegare nella produzione di Aceto BalsamicoTradizionale devono possedere caratteri tecnologicidifferenti da quelli richiesti per altri tipi di aceto. Unmodo empirico ma efficace per il mantenimentodelle colture miste è quello di praticare frequentirinnovi senza attendere che i batteri aceticiesauriscano l’etanolo. Le colture, mantenute in modostatico, hanno una attività metabolica rallentata perla scarsa disponibilità di ossigeno e questo consentedi dilatare l’intervallo tra un rinnovo ed il successivo.In ogni caso, va sempre controllata la concentrazionedi etanolo che non deve scendere al di sotto del3% v/v al fine di garantire la pronta attività dellacoltura. La presenza di batteri acetici vitali ed attivinella coltura starter è condizione necessaria ma nonsufficiente a garantire il successo dell’ossidazioneacetica del mosto cotto fermentato, processoche trova nella composizione stessa del mosto ilsuo limite maggiore. Condizioni non permissivedella crescita batterica annullano completamentei benefici dell’impiego di colture starter. L’elevataconcentrazione zuccherina è una delle cause piùdiffuse dell’inibizione della crescita dei batteri acetici.

2005 - Homogeneity of interspecific hybrids between Saccharomyces cerevisiae and Saccharomyces uvarum by phenotypic and transcriptional analysis. [Articolo su rivista]
Solieri, Lisa; Gullo, Maria; DE VERO, Luciana; Antunez, O; PEREZ ORTIN J., E; Giudici, Paolo

Oenological traits, such as temperature profile and production of certain metabolites, were tested for four interspecifc hybrids obtained by “spore to spore” crossing between Saccharomyces cerevisiae and Saccharomyces uvarum strains and uniformity of their inheritance was found. PCR/RFLP analysis of ITSregions was carried out to confirm the hybrid nature of the strains. They showed an additive profile with five bands of the respective 325, 230, 170 and 125 bp.Finally gene expression study was performed by comparative DNA macroarray analysis of the hybrids and the preliminary results showed that the global geneexpression patterns of hybrids are remarkably similar to one another.In conclusion, the data obtained by two different approaches, such as metabolic and transcriptomic strategies, suggest a large degree of homogeneity amonginterspecific hybrids between S. cerevisiae and S. uvarum. Moreover, theuniformity of F1 hybrids advises that the oenological trait inheritance mechanismis highly constant and reproducible

2005 - I batteri acetici. [Capitolo/Saggio]
Giudici, Paolo; Gullo, Maria; DE VERO, Luciana

I batteri acetici. Tassonomia, Ecologia, fisiologia, esigenze nutrizionali

2005 - Theoretical approach to age determination of Traditional BalsamicVinegar [Abstract in Atti di Convegno]
Landi, S; Gullo, Maria; Solieri, Lisa; DE VERO, Luciana; Giudici, Paolo

Theoretical approach to determine the age of Traditional Balsamic Vinegar

2005 - Vinegar eels: state of the art and perspectives. [Relazione in Atti di Convegno]
Petroni, G; Schrallhammer, M; Gullo, Maria

vinegar eels

2005 - vinegars and acetic acid bacteria international symposium [Esposizione]
Giudici, Paolo; Gullo, Maria; Solieri, Lisa; DE VERO, Luciana; Pulvirenti, Andrea; W., Ludwig; F., Barja; J., Bourgeois; J. M., Guillamon; A., Mas; P., Raspor

The key objective in planning the scientific programme was to ensure that the event would achieve the highest levels of scientific interest and topicality. Hence, the programme combines plenary session lectures, symposium sessions, as well as poster session.It would give a comprehensive overview of the most recent development in field of acetic acid bacteria and vinegar production and would surely stimulate fruitful discussions between attendees.One of the purposes of the meeting is also to create an international network for all the laboratories working in this field.

Giudici, Paolo; Gullo, Maria; DE VERO, Luciana; Solieri, Lisa

L’uso dei microrganismi nei processi di trasformazione degli alimenti è antecedente la loro scoperta e la comprensione del loro ruolo, che risale a soli due secoli fa. Da allora la microbiologia applicata alla trasformazione alimentare è stata oggetto di studi scientifici approfonditi che hanno consentito ricadute tecnologiche consistenti. Tuttavia, per quanto riguarda i prodotti tipici l’atteggiamento di riverenza verso ciò che si ritiene tradizione non consente un approccio razionale e, gli aspetti microbiologici sono i primi ad essere trascurati ed immolati sull’altare della tipicità. Questo tipo di atteggiamento ha fatto si che un prodotto antico come l’Aceto Balsamico Tradizionale, di fatto, non sia stato studiato approfonditamente nei suoi aspetti microbiologici ed oggi non è disponibile una sufficiente letteratura scientifica adeguata.

2004 - Batteri dell’Aceto Balsamico Tradizionale: caratteristiche fenotipiche, molecolari e tecnologiche. [Relazione in Atti di Convegno]
Gullo, M.; Solieri, Lisa; DE VERO, Luciana; Landi, S.; Giudici, Paolo

2004 - Cristallizzazione dell'aceto balsamico tradizionale [Articolo su rivista]
Giudici, Paolo; Pulvirenti, Andrea; DE VERO, Luciana; S., Landi; Gullo, Maria

Il processo di produzione dell’Aceto BalsamicoTradizionale (ABT) è complesso e dipendente davariabili fisiche, chimiche e biologiche. Durantel’invecchiamento si assiste ad una rilevanteconcentrazione dei soluti che possono dare luogoalla formazione di cristalli, in quantità tale daoccupare l’intero volume del contenitore. Nelpresente lavoro sono stati analizzati campioni diABT prelevati da barili contenenti il prodotto piùvecchio e che presentavano precipitato solido ingrande quantità. Il precipitato è risultato esserecomposto prevalentemente da glucosio ed inmisura minore da fruttosio, con un rapportofra i due zuccheri diverso da quello osservatonelle uve. La presenza di cristalli di zuccheronell’ABT è spiegato da due cause concomitanti:l’elevata concentrazione dei soluti e il rapportoglucosio/fruttosio a favore del primo. Lamaggiore presenza percentuale di glucosio èimputabile al tipo di lieviti che hanno condotto lafermentazione.Traditional Balsamic Vinegar (ABT) production iscomplex and influenced by physical, chemical,and biological parameters. During the aging,a remarkable concentration of soluble solids isobserved. These solids can make a great amountof crystals that fills the whole volume of thebottle. In the present work, the precipitatedsoluble solids from oldest ABT samples wereanalyzed.The precipitate is mainly glucose and in smalleramount is fructose. Therefore the ratio betweenthe two sugars is different from the one in thegrapes. The sugar crystals observed in aged ABTare explainable on the basis of two associatedcauses: the elevated soluble solids concentrationand the ratio glucose/fructose pro glucose. Thegreater amount of glucose is due to the yeastspecies that ferment the cooked must.

2004 - I microrganismi dell'aceto balsamico. Atti convegno:"anche la tradizione va studiata" ricerche preliminari per l'individuazione di starter per l'Aceto Balsamico Tradizionale. [Curatela]
Giudici, Paolo; Gullo, Maria; Pulvirenti, Andrea; DE VERO, Luciana; Solieri, Lisa

Il ruolo e l'importanza dei microrganismi sulla qualità dell'aceto balsamico tradizionale.

2004 - Il prosciutto cotto quale sistema modello per lo studio della previsione della shelf-life. [Articolo su rivista]
DE VERO, Luciana; M., Taccogna; Solieri, Lisa; Gullo, Maria; Puglisi, Maria Laura; Fava, Patrizia; Giudici, Paolo

Nella presente ricerca si è inteso valutare comealcune tecniche di conservazione possanoincidere sull’evoluzione della complessiva del prosciutto cotto, scelto qualesistema modello per lo studio della inprodotti alimentari non restrittivi per la crescitadei microrganismi. Predire la shelf-life delprosciutto cotto affettato risulta molto difficilein quanto la contaminazione casuale dopo lacottura e le condizioni igieniche delle zonedi affettamento e confezionamento rendonol’intero sistema estremamente aleatorio. Nellaricerca effettuata, i campioni di prosciutto sonostati inoculati con microrganismi specifici dialterazione precedentemente isolati da prosciuttocotto alterato. In una seconda prova sono statiimpiegati trattamenti con azoto allo stesso finedi diminuire l’aleatorietà del sistema dovuta allacontaminazione casuale.

2004 - Influenza della composizione del mezzo sull’attività biologica dell’ABT. [Relazione in Atti di Convegno]
DE VERO, Luciana; Landi, Sara; Gullo, Maria; Giudici, Paolo

La composizione del mosto cotto esercita una forte pressione selettiva sui microrganismi presenti determinando la prevalenza di lieviti o batteri acetici in funzione della combinazioni di variabili quali, il pH, la concentrazione in solidi solubili, la presenza di etanolo o di acido acetico. In sei differenti composizioni del mezzo ottenuti variando la percentuale di mosto cotto e mosto fresco d’uva, sono stati osservati andamenti fermentativi significativamente diversi, ma riconducibili a due tipologie: una a prevalente attività fermentativa ad opera di lieviti fruttosofili e l’altra a prevalente attività ossidativa ad opera di batteri acetici. Ciò che sembra maggiormente determinare lo sviluppo di lieviti o di batteri è la concentrazione zuccherina iniziale. Concentrazioni del mezzo superiori ai 30 °Brix, in presenza di acido acetico (1% circa) e valori di pH bassi, imprimono una forte pressione selettiva che consente lo sviluppo di poche specie di lievito, prevalentemente fruttosofile, ma non dei batteri acetici. Al contrario concentrazioni di solidi solubili inferiori a 30 °Brix non inibiscono lo sviluppo dei batteri acetici. Inoltre, alcuni prodotti del metabolismo microbico possono essere impiegati come indicatori indiretti della prevalenza di un determinato gruppo nel processo fermentativo.

2004 - Lieviti e zuccheri nell’Aceto Balsamico Tradizionale. [Relazione in Atti di Convegno]
Landi, S.; Castellari, L.; Gullo, Maria; Solieri, Lisa; DE VERO, Luciana; Giudici, Paolo

2004 - Limits of r-DNA-NTS2 regions on the taxonomy of Saccharomyces genus [Relazione in Atti di Convegno]
Pulvirenti, Andrea; Solieri, Lisa; DE VERO, Luciana; Gullo, Maria; Giudici, Paolo

The aim of this work was to test different molecular techniques for determining which was the most effective in the identification of Saccharomyces cerevisiae strains. In particular, polymerase chain reaction--restriction fragment length polymorphism (PCR-RFLP) analysis of the internal transcribed spacer (ITS) regions and the nontranscribed spacer 2 (NTS2) region, sequencing of the D1/D2 domain, and electrophoretic karyotyping were applied to 123 yeast strains isolated from different sourdoughs and tentatively attributed to the species S. cerevisiae. All of the strains tested showed an identical PCR-RFLP pattern for the ITS regions, an identical nucleotide sequence of the D1/D2 domain, and the typical electrophoretic karyo type of S. cerevisiae. In contrast, 14 out of the 123 strains tested showed some polymorphism with BanI restriction analysis of the NTS2 region. Our results indicate that while the sequencing of the D1/D2 domain, the PCR-RFLP analysis of the ITS regions, and the electrophoretic karyotype can be employed successfully to identify S. cerevisiae strains, PCR-RFLP analysis of the NTS2 region does not allow a consistent and accurate grouping for S. cerevisiae strains. The fact that the NTS2 region of a small number of strains (8.78% of the total strains tested) is different from that of the other S. cerevisiae strains confirms that molecular methods should always be tested on a great number of strains.

Giudici, Paolo; Gullo, Maria; DE VERO, Luciana; G., Masini

processo di produzione dell’Aceto Balsamico Tradizionale di Reggio Emilia (ABT) richiede almeno 12 anni di invecchiamento e necessita di trasferimenti tra un barile e l’altro con conseguente miscelazione di prodotti di diversa età. Tutto ciò rende molto difficile effettuare un bilancio preciso della resa di trasformazione del mosto cotto in ABT, della stima della reale età dell’ABT nonché della massima produttività ammissibile di una batteria tale per cui l’età media dell’ABT sia sempre superiore ai 12 anni previsti dal disciplinare di produzione. Nel presente lavoro è stato sviluppato un modello teorico, che a partire dal volume della batteria e del flusso in ingresso di mosto cotto necessario ad alimentare la batteria stessa, consente di calcolare l’età dell’ABT e stimare la massima produzione ammissibile di ABT. Il modello è applicabile a batterie in equilibrio che abbiano almeno 12 anni dalla data di costituzione. L’età dell’ABT in uscita è in funzione del rapporto tra la massa di soluti nella batteria ed il flusso di soluti in ingresso.The production of Traditional Balsamic Vinegar of Reggio Emilia (ABT) requires at least 12 years of aging. The vinegar is transferred from a barrel to another resulting in a mix of products with different ages. Therefore it is very difficult to assess the age and the precise yield of ABT from cooked must. The real age of the ABT, as well as the maximum admissible productivity for barrels, are important quality parameters. The ABT good manufacturing practices manual requires at least 12 years aging. In this work the AA have developed a theoretical model which allows to calculate the age and the maximum admissible productivity of ABT for barrels. The model is based on the volume of the barrels and on the incoming flow of the cooked must needed to feed the same barrels. The model is valid for barrels at the equilibrium which are at least 12 years old. The age of the ABT in exit is a function of the mass of solutes in the barrels and the flow of solutes in entry.

2004 - Metodi indiretti per lo studio dei microrganismi dell’ABT. [Relazione in Atti di Convegno]
Pulvirenti, Andrea; Solieri, Lisa; Gullo, Maria; Giudici, Paolo

metodi coltura-indipendenti per la caratterizzazione della microflora dell'ABT

2004 - Nuove frontiere nello studio dei batteri acetici: la DGGE [Relazione in Atti di Convegno]
DE VERO, Luciana; Gullo, Maria; Solieri, Lisa; Landi, Sara; Giudici, Paolo

I batteri acetici (B.A.) sono microrganismi difficili da isolare e conservare in coltura pura nonostante i moltissimi mezzi di crescita e le condizioni di incubazione impiegate. Il rischio maggiore che si incontra con le procedure convenzionali adottate nello studio di popolazioni microbiche, è quello di isolare non tanto le specie o i ceppi che hanno condotto l’ossidazione, ma quelli più facilmente isolabili anche se numericamente meno importanti. A causa della non-coltivabilità dei B.A. si è reso necessario studiare le popolazioni selvagge degli aceti con l’ausilio di tecniche che non prevedano l’isolamento di questi microrganismi. Una tecnica molecolare coltura-indipendente è risultata essere la PCR-DGGE (Polymerase Chain Reaction - Denaturing Gradient Gel Electophoresis).I risultati ottenuti sono di supporto a due considerazioni, una di interesse più generale che conferma l’utilità della DGGE nello studio delle popolazioni batteriche dell’aceto. L’altra più specifica e da confermare con studi ulteriori, è relativa alle specie di batteri acetici riscontrabili in una ossidazione spontanea; tali specie possono essere in numero molto limitato e, in alcuni casi, addirittura riconducibili ad una sola specie dominante.

2004 - Occurrence and dominance of yeast species in sourdough [Articolo su rivista]
Pulvirenti, Andrea; Solieri, Lisa; Gullo, Maria; DE VERO, Luciana; Giudici, Paolo

Aims: The aim of this work is to identify the dominant yeast species in homemade sourdoughs. Methods and Results: PCR/restriction fragment length polymorphism analysis of internal transcribed spacer regions was used for the identification of isolates and the data were confirmed with phenotypic tests. The strains belonging to Saccharomyces cerevisiae were identified to strain level by analysis of inter-delta regions. Conclusion: This work shows that the dominant species in homemade sourdoughs can differ from each other. Saccharomyces cerevisiae was found to be the dominant species, followed by the Candida milleri, C. humilis, S. exiguus and Issatchenkia orientalis. The inter-delta regions of S. cerevisiae strains showed high polymorphism. Significance and Impact of the Study: Occurrence of single, non-Saccharomyces species and S. cerevisiae polymorphism in the yeast populations of sourdough samples.

2004 - Pressione selettiva del mosto cotto sull’attività biologica dell’ABT. [Articolo su rivista]
Gullo, Maria; DE VERO, Luciana; S., Landi; Giudici, Paolo

La composizione del mosto cotto, utilizzato per la produzione di Aceto Balsamico Tradizionale (ABT), esercita una forte pressione selettiva sui microrganismi presenti. La prevalenza di lieviti o batteri acetici è in funzione delle combinazioni di variabili quali, pH, concentrazione in solidi solubili, presenza di etanolo e acido acetico. In sei differenti tesi ottenute variando la composizione del mezzo, sono stati osservati andamenti fermentativi significativamente diversi ma riconducibili a due tipologie: una a prevalente attività fermentativa ad opera di lieviti fruttosofili e l’altra a prevalente attività ossidativa ad opera di batteri acetici (B.A.). Inoltre, alcuni ceppi di B.A. isolati da mosti per la produzione di ABT sono stati saggiati per la loro capacità di crescere in presenza di concentrazioni crescenti di glucosio ed etanolo. Dai risultati si evince che l’ostacolo maggiore allo sviluppo dei B.A. è rappresentato dall’elevata concentrazione zuccherina dei mosti cotti e concentrati.The composition of the cooked must has a strong selective pressure on the microorganisms. The prevalence of yeasts or of acetic acid bacteria is determined by the combinations of some parameters such as pH, concentration in soluble solids, presence of ethanol or acetic acid. Significantly different fermentative processes have been observed in six different trials, obtained varying the composition of the medium. The processes are referable to two typologies: one with a prevailing fermentative activity of fructosophilic yeasts and the other one with a prevailing oxidative activity due to the acetic acid bacteria (B.A.). Furthermore, some B.A. strains isolated from musts used in the Traditional Balsamic Vinegar production, have been tested for their ability to grow in presence of increasing concentrations of glucose and ethanol. On the basis of the results it is evident that the greatest hurdle to the growth of B.A. is the elevated sugary concentration of the cooked and concentrated musts.

2004 - Ricerche finalizzate alla tutela e tipicità dell'Aceto Balsamico Tradizionale di Reggio Emilia [Esposizione]
Giudici, Paolo; Gullo, Maria; DE VERO, Luciana; Pulvirenti, Andrea; U., Rangone

La valorizzazione e la tutela dell’Aceto Balsamico Tradizionale, al pari di qualsiasi altro prodotto alimentare tradizionale, non può prescindere dalla conoscenza delle ragioni che lo rendono così specifico e particolare. La ricerca scientifica, oltre ad essere lo strumento di conoscenza necessario alla comprensione della complessità dell’ABT, è anche veicolo di promozione, nel rispetto della chiarezza, dell’autenticità e dell’oggettività, senza ricorrere a spiegazioni aleatorie e fantasiose, che nulla hanno a che fare con la concretezza dell’ABT, frutto dell’acquisizione empirica della conoscenza.

2003 - Candida humilis - dominant species in sourdoughs for the production of durum wheat bran flour bread [Articolo su rivista]
Gullo, Maria; Romano, Ad; Pulvirenti, Andrea; Giudici, Paolo

Yeasts present in the sourdough that is generally used for the production of durum wheat bran flour bread were isolated and identified. Samples were taken during the rebuilding phase and at different intervals of time in order to monitor the population dynamics. The results obtained from the phenotypic studies were further confirmed by the molecular studies and enabled us to affirm that most of the strains, more than 95%, belong to the species Candida humilis. The dominance of C. humilis was steady in time. The isolations were carried out at sufficiently long intervals so that it was possible to ascertain that the conditions in which the sourdough is kept are fundamental to the microbiological stability of the dough.

2003 - Dominant yeast species in traditional sourdoughs [Abstract in Atti di Convegno]
Solieri, Lisa; Pulvirenti, Andrea; Gullo, Maria; Giudici, Paolo

Dominant yeast species in traditional sourdoughs

2003 - In Vivo Interspecific Hybrids of Saccharomyces Species [Abstract in Atti di Convegno]
Pulvirenti, Andrea; Zambonelli, C.; Gullo, Maria; Giudici, Paolo

Costruction of in Vivo Saccharomyces Species Interspecific Hybrids

2003 - Microflora Y La Tecnología De Producción Del Vinagre Balsámico Tradicional. [Relazione in Atti di Convegno]
Giudici, Paolo; Gullo, Maria; Pulvirenti, Andrea; Solieri, Lisa; DE VERO, Luciana

Acetic acid bacteria of vinegar

2003 - Sorting of mitocondrial DNA and proteins in the progeny of Saccharomyces interspecific hybrids [Articolo su rivista]
De Vero, Luciana; Pulvirenti, Andrea; Gullo, Maria; Bonatti, Piera; Giudici, Paolo

The mitochondrial transmission to the progeny of interspecific hybrids Saccharomyces cerevisiae x Saccharomyces uvarum was investigated. It was observed that la progenie degli hybrids ha un solo tipo di mitocondri parentali come è stato osservato attraverso l’analisi RFLP dell’intero mtDNA. The mitochondrial proteins, invece, sono il risultato della ricombinazione del genoma dei due parentali. We suppose an important role of mitochondrial proteins in the process of mitochondrial transmission in yeast and hypothesize that inheritance of mtDNA may depend upon nuclear DNA genes. It seems to be probable that uniparental inheritance is independent on position of mitochondria in the buds of zygotes when the haploid cells fuse.

2003 - Studio molecolare e fenotipico di lieviti in paste acide tradizionali [Articolo su rivista]
Solieri, Lisa; DE VERO, Luciana; Gullo, Maria; Pulvirenti, Andrea

In questo lavoro è stato condotto uno studiodelle specie di lievito più rappresentatein impasti acidi tradizionali, preparatisenza l’aggiunta di lieviti starter. Tali speciesi contraddistinguono per importanzatecnologica in quanto numericamente prevalentie maggiormente responsabili delprocesso fermentativo. Le procedure diidentificazione adottate, basate su tecnichesia molecolari che fenotipiche, hannoconsentito di evidenziare una grande biodiversitànegli impasti acidi esaminati, ciascunodei quali rappresenta un unicuumsotto il profilo eumicetico.In this work a study on dominant yeastsspecies was carried out, using phenotypicand molecular techniques. These speciesare of technological interest since theyare the main responsible of the fermentationprocess. The obtained identificationsindicate that the examined home-madesourdoughs were characterized by a greatbiodiversity: each has got a distinguishingand unique yeast profile. The prevalenceof different yeast species in sourdoughssuggests to consider in additionto S. cerevisiae, also C. humilis, C. milleri,I. orientalis, and S. exiguus as speciessuitable for bread making.

2003 - Transmission of mt DNA and mitochondrial proteins in the progeny of Saccharomyces hybrids [Abstract in Atti di Convegno]
DE VERO, Luciana; Pulvirenti, Andrea; Gullo, Maria; Solieri, Lisa; Giudici, Paolo

Transmission of mt DNA and mitochondrial proteins in the progeny of Saccharomyces hybrids

2003 - Transmission of mtdna and mitochondrial proteins in the progeny of Saccharomyces interspecific hybrids. [Relazione in Atti di Convegno]
DE VERO, Luciana; Pulvirenti, Andrea; Gullo, Maria; Solieri, Lisa; Giudici, Paolo

2002 - Microbiologia degli aceti [Esposizione]
Giudici, Paolo; Pulvirenti, Andrea; Gullo, Maria

Il processo di produzione dell’Aceto Balsamico Tradizionale (ABT) è complesso ed è dipendente da variabili fisiche, chimiche e biologiche. Durante l’invecchiamento si assiste ad una rilevante concentrazione dei soluti tale per cui alcuni di essi possono precipitare dando luogo alla formazione di cristalli in quantità tale da essere visibili ad occhio nudo ed in alcuni casi possono occupare uno spazio corrispondente ad un terzo del prodotto. Nel presente lavoro abbiamo preso in considerazione campioni di ABT, prelevati dai barili contenente il prodotto più vecchio, che presentavano precipitato solido in grande quantità. Il precipitato è risultato essere rappresentato prevalentemente da glucosio ed in misura minore da fruttosio, mentre il rapporto fra i due zuccheri nel prodotto è risultato meno ampio, mantenendosi tuttavia lontano dal rapporto di circa 1/1 che si riscontra nelle uve. La ragione della formazione del precipitato nell’ABT invecchiato è spiegabile sulla base di due cause concomitanti: l’elevata concentrazione dei soluti, il rapporto glucosio/fruttosio spostato a favore del primo. La maggiore presenza percentuale di glucosio è imputabile al tipo di lieviti che hanno fermentato il mosto cotto base di partenza.

2002 - Uniparental Mitochondrial Inheritance in Saccaromyces spore coniugation. [Abstract in Atti di Convegno]
Pulvirenti, Andrea; Gullo, Maria; DE VERO, Luciana; Giudici, Paolo

Uniparental Mitochondrial Inheritance in Saccaromyces spore coniugation.

2001 - DNA fingerprinting methods used for identification of yeasts isolated from Sicilian sourdoughs [Articolo su rivista]
Pulvirenti, Andrea; C., Caggia; C., Restuccia; Gullo, Maria; Giudici, Paolo

The nature of sourdough yeast microflora was investigated. Samples were collected from different bakeries that do not use starter cultures, but rely on the traditional art of bread making. Pulsed field gel electrophoresis (PFGE), PCR/RFLP of the Non-Transcribed Spacer 2 (NTS2), the inter delta regions and the Internal Transcribed Spacer (ITS) of the ribosomal DNA (rDNA and partial sequencing of the 26S rDNA were used to identify and differentiate the yeast cultures isolated. In particular, PCR/RFLP of the ITS region, with restriction enzyme Hae III made it possible to differentiate Candida milleri from Candida humilis. A high degree of polymorphism was observed in the inter-delta regions of the strains belonging to the S. cerevisiae. species; contrary to what has been mentioned in literature, strains with the same profile are not necessarily identical. Saccharomyces cerevisiae, Saccharomyces cerevisiae old type anamensis, Issatchenkia orientalis, Candida mil[eri and Candida humilis were found to be the predominant species in Sicilian sourdough.

2000 - Interazione tra lieviti e batteri lattici delle paste acide. [Articolo su rivista]
Giudici, Paolo; Gullo, Maria; F., Galvano; D., Romano

Interazione tra lieviti e batteri lattici delle paste acide.