Free volatie compounds of cv. Pedro Giménez (Vitis vinifera L.) white grape must grown in San Juan, Argentina.

The free aromatic composition of must from Pedro Giménez grapes, grown in San Juan, Argentina, was characterised. Samples from the vintages of 2008 and 2009 were analysed by gas chromatography-mass spectrometry-solid phase microextraction (GC-MS-SPME). Higher alcohols, terpenes, C13-norisoprenoids, esters, aldehydes and ketones were quantifed. The calculation of the odour activity values (OAVs) revealed that β-damascenone, α-ionone, β-linalool, geraniol, ethyl butanoate, hexanoate and octanoate were the most prevalent aroma-active compounds of the grape variety. However, the remaining 42 aromatic compounds that registered OAVs less than 1 could potentially contribute to the favour of Pedro Giménez grapes. The measured monoterpene levels indicate that the Pedro Giménez grape can be considered a neutral variety. This is the frst report describing the main potential free aroma contributors of Pedro Giménez grapes in two consecutive years.Fil: Maturano, Yolanda Paola. Universidad Nacional de San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Nally, Maria Cristina. Universidad Nacional de San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan; ArgentinaFil: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan; Argentin

Selection of Native Non-Saccharomyces Yeasts with Biocontrol Activity against Spoilage Yeasts in Order to Produce Healthy Regional Wines

Two major spoilage yeasts in the wine industry, Brettanomyces bruxellensis and Zygosaccharomyces rouxii, produce off-flavors and gas, causing considerable economic losses. Traditionally, SO2 has been used in winemaking to prevent spoilage, but strict regulations are in place regarding its use due to its toxic and allergenic effects. To reduce its usage researchers have been searching for alternative techniques. One alternative is biocontrol, which can be used either independently or in a complementary way to chemical control (SO2). The present study analyzed 122 native non-Saccharomyces yeasts for their biocontrol activity and their ability to be employed under fermentation conditions, as well as certain enological traits. After the native non-Saccharomyces yeasts were assayed for their biocontrol activity, 10 biocontroller yeasts were selected and assayed for their ability to prevail in the fermentation medium, as well as with respect to their corresponding positive/negative contribution to the wine. Two yeasts that satisfy these characteristics were Wickerhamomyces anomalus BWa156 and Metschnikowia pulcherrima BMp29, which were selected for further research in application to mixed fermentations.Fil: Kuchen, Benjamín. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Maturano, Yolanda Paola. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Mestre Furlani, María Victoria. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentin

Determinación de actividades celulolítica y xilanolítica en levaduras no-Saccharomyces de origen enológico

Una de las características más importantes de la calidad del vino es su aroma. Las celulasas y hemicelulasas degradan los polisacáridos de las paredes celulares y de esta manera pueden incrementar el aroma frutado de los vinos debido a la liberación de precursores aromáticos. Además mejora la clarificación y filtración del jugo de uva. Cabe destacar que la mayoría de los productos comerciales usados para aumentar el aroma del vino poseen altos niveles de sustancias que degradan celulosa y xilano. Según estudios previos, las levaduras que secretan enzimas celulolíticas y xilanolíticas son las pertenecientes al grupo de las ?no-Saccharomyces?, las cuales, recientemente, suelen emplearse en cultivos mixtos con Saccharomyces cerevisiae y de esta manera combinar el potencial de las levaduras que participan en él. Objetivo: detectar cuali y cuantivamente actividades celulolítica y xilanolítica en levaduras no- Saccharomyces autóctonas de origen enológico. Se emplearon 45 aislamientos pertenecientes al IBT-UNSJ. La determinación cualitativa se llevó a cabo mediante detección en placa con medios inductores específicos para cada actividad. La presencia de actividad enzimática se confirmó mediante la formación de halos de degradación (Incubación: 25ºC-168h). La determinación cuantitativa se realizó mediante la técnica colorimétrica DNS con sus respectivos sustratos bufferizados a dos pH: 4 y 5,3. Resultados: cualitativamente se detectaron 13 aislamientos con actividades xilanolítica y 8 celulolítica, de los cuales 3 expresaron ambas actividades. Las levaduras que mostraron resultados positivos fueron analizadas cuantitativamente y en todos los casos se registraron valores menores a pH 4. En la actividad xilanolítica la producción enzimática fue entre 0,26 y 3,68 nkat/ml y en la celulolítica 0,17 y 1,49 nkat/ml. Conclusión: Los resultados obtenidos sugieren que las levaduras ensayadas pueden realizar un aporte positivo en cuanto a la degradación de polímetros presentes en el mosto, posibilitando su empleo en la formulación de cultivos mixtos.The bouquet is one of the most important characteristics of the wine quality. Polysaccharides of cell walls are degraded by cellulases and hemicellulases, and so they can increase the fruity bouquet of wines due to the liberation of aromatic precursors. The most of commercial products used to increase the bouquet of wines have high levels of substances that degrade cellulose and xylan. In previous studies, the yeasts that belong to “non-Saccharomyces” group secrete cellulolitic and xylanolitic enzymes. Recently, there were used mixed cultures of Saccharomyces and non-Saccharomyces yeasts in order to combine the potential of the yeasts. Objective: to detect qualitatively and quantitatively cellulolitic and xylanolitic activities in indigenous non-Saccharomyces yeasts from enological origin. There were used 45 isolations belonging to IBT-UNSJ. Qualitative determinations were conducted by plate detection using specific inducting media for both activities. Positive enzymatic activity was confirmed by the formation of degraded halos (25°C – 168 h). Quantitative determinations were carried out by colorimetric DNS technique with buffer substrates using two pH´s values: 4.00 and 5.3. Results: Qualitatively, there were detected 13 isolations that expressed xylanolitic activity and 8 isolations with cellulolitic activity; three of them, showed both activities. The yeasts that expressed positive results were quantitatively analyzed and in all the cases there were registered lesser values at pH 4.00. The enzymatic production of xylanases was between 1,3 and 3,7 nkat/ml and the production of cellulases was between 0,17 and 1,97 nkat/ml. Conclusion: The results suggest that analyzed yeast isolations can realize a positive contribution to the degradation of polymers present in the must. These yeasts could be used in the formulation of mixed cultures.Fil: Maturano, Yolanda Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentin

Determinación de actividades celulolítica y xilanolítica en levaduras no-Saccharomyces de origen enológico

Una de las características más importantes de la calidad del vino es su aroma. Las celulasas y hemicelulasas degradan los polisacáridos de las paredes celulares y de esta manera pueden incrementar el aroma frutado de los vinos debido a la liberación de precursores aromáticos. Además mejora la clarificación y filtración del jugo de uva. Cabe destacar que la mayoría de los productos comerciales usados para aumentar el aroma del vino poseen altos niveles de sustancias que degradan celulosa y xilano. Según estudios previos, las levaduras que secretan enzimas celulolíticas y xilanolíticas son las pertenecientes al grupo de las ?no-Saccharomyces?, las cuales, recientemente, suelen emplearse en cultivos mixtos con Saccharomyces cerevisiae y de esta manera combinar el potencial de las levaduras que participan en él. Objetivo: detectar cuali y cuantivamente actividades celulolítica y xilanolítica en levaduras no- Saccharomyces autóctonas de origen enológico. Se emplearon 45 aislamientos pertenecientes al IBT-UNSJ. La determinación cualitativa se llevó a cabo mediante detección en placa con medios inductores específicos para cada actividad. La presencia de actividad enzimática se confirmó mediante la formación de halos de degradación (Incubación: 25ºC-168h). La determinación cuantitativa se realizó mediante la técnica colorimétrica DNS con sus respectivos sustratos bufferizados a dos pH: 4 y 5,3. Resultados: cualitativamente se detectaron 13 aislamientos con actividades xilanolítica y 8 celulolítica, de los cuales 3 expresaron ambas actividades. Las levaduras que mostraron resultados positivos fueron analizadas cuantitativamente y en todos los casos se registraron valores menores a pH 4. En la actividad xilanolítica la producción enzimática fue entre 0,26 y 3,68 nkat/ml y en la celulolítica 0,17 y 1,49 nkat/ml. Conclusión: Los resultados obtenidos sugieren que las levaduras ensayadas pueden realizar un aporte positivo en cuanto a la degradación de polímetros presentes en el mosto, posibilitando su empleo en la formulación de cultivos mixtos.The bouquet is one of the most important characteristics of the wine quality. Polysaccharides of cell walls are degraded by cellulases and hemicellulases, and so they can increase the fruity bouquet of wines due to the liberation of aromatic precursors. The most of commercial products used to increase the bouquet of wines have high levels of substances that degrade cellulose and xylan. In previous studies, the yeasts that belong to “non-Saccharomyces” group secrete cellulolitic and xylanolitic enzymes. Recently, there were used mixed cultures of Saccharomyces and non-Saccharomyces yeasts in order to combine the potential of the yeasts. Objective: to detect qualitatively and quantitatively cellulolitic and xylanolitic activities in indigenous non-Saccharomyces yeasts from enological origin. There were used 45 isolations belonging to IBT-UNSJ. Qualitative determinations were conducted by plate detection using specific inducting media for both activities. Positive enzymatic activity was confirmed by the formation of degraded halos (25°C – 168 h). Quantitative determinations were carried out by colorimetric DNS technique with buffer substrates using two pH´s values: 4.00 and 5.3. Results: Qualitatively, there were detected 13 isolations that expressed xylanolitic activity and 8 isolations with cellulolitic activity; three of them, showed both activities. The yeasts that expressed positive results were quantitatively analyzed and in all the cases there were registered lesser values at pH 4.00. The enzymatic production of xylanases was between 1,3 and 3,7 nkat/ml and the production of cellulases was between 0,17 and 1,97 nkat/ml. Conclusion: The results suggest that analyzed yeast isolations can realize a positive contribution to the degradation of polymers present in the must. These yeasts could be used in the formulation of mixed cultures.Fil: Maturano, Yolanda Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentin

Pectinolytic activity expressed by yeasts isolated from oenological environments

Introduction: Pectolytic enzymes play an important role in the winemaking process due to the fact that they improve the extraction of colour and aroma compounds. They also improve clarification and filtration processes of musts and wines. These enzymes break up pectin and weaken the cell wall, reducing the viscosity of musts and improving the extraction of the different compounds. Pectinases used in the food industry are commercially produced by Aspergillus niger. Saccharomyces and non- Saccharomyces yeasts present an alternative source for the large-scale production of commercial enzymes. Yeasts have advantages compared to filamentous fungi with regard to the production of pectinases, because they are unicellular, their growth is relatively simple, and in some species the growth medium does not require an inducer. The aim of this work was to study the pectinase activity of 162 isolated yeasts (47 non- Saccharomyces and 115 Saccharomyces sp.). Qualitative assay was carried out on plates with pectin as substrate, at 25ºC, pH 4.0 and 6.5 during 72h, in order to select yeasts having pectinolytic activity. Results were considered positive when colonies were surrounded by a degradation halo. After that, those isolates were grown anaerobically, for 72 h at 30ºC using two media: an inducing medium (0,67% YNB; 0,5% pectin and 10% glucose), and a non-inducing medium (0,67% YNB; and 10% glucose). For determination of pectinolytic activity, a reaction mixture of 0.1 ml of supernatant, 0.9 ml of 0.5% (w/v) pectin in 0.05 M sodium acetate buffer (pH 5) was used. It was prepared and incubated in a water bath at 37°C for 1 h (yeasts inoculated in inducing medium) and 24 h (yeasts inoculated in non-inducing medium). Pectinolytic activity was determined by estimation of reducing sugars by DNS technique. Results: of the 162 yeasts, 24 isolations were able to hydrolyze pectin under both pH conditions (14 Saccharomyces sp. and 10 non- Saccharomyces). Highest amounts of yeast isolations were detected at pH 6.5. All yeasts, developed in inducing and non- inducing media, expressed pectinolytic activity. Fifty percent of species from Saccharomyces genus registered the greatest values of pectinolytic activity growing in inducing medium. All species belonging to the non-Saccharomyces genera which were cultured in non-inducing medium expressed highest activity. This suggests that pectinase synthesis may be partially constitutive for these non- Saccharomyces yeasts. Conclusion: this study clearly revealed the potential of indigenous yeasts to produce useful enzymes to catalyze desired biotransformations during wine fermentation and they offer an alternative source of these enzymes as well.Fil: Maturano, Yolanda Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Castellanos, Lucia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaVI Congreso Argentino de Microbiología GeneralVilla Carlos PazArgentinaSociedad Argentina de Microbiología Genera

Toward application of biocontrol to inhibit wine spoilage yeasts: The use of statistical designs for screening and optimisation

Spoilage yeasts generate considerable economic losses in the wine industry, and although sulphur dioxide (SO2) is traditionally used for control, its use has become controversial because of its negative effects on health. Biocontrol has emerged as a partial alternative to SO2, and most research has focused on the selection of biocontrol yeasts and/or the mechanisms involved, while little research has been directed to the environmental conditions that make biocontrol effective for application. When there are two or more interacting yeasts, the physicochemical factors that affect their antagonism are many and therefore the application of biocontrol is complex. To reduce SO2, the present study aimed to elucidate biocontrol mechanisms of two yeast interactions and to establish optimal physicochemical conditions for biocontrol of the spoilage yeast during grape must fermentation. Through the use of statistical design, it was possible to find relevant physicochemical factors and optimise them. Wickerhamomyces anomalus “BWa156” developed an active supernatant against Zygosaccharomyces rouxii “BZr6” while supernatant from Metschnikowia pulcherrima “BMp29” was ineffective. In mixed must fermentations, the first interaction (BWa156 vs. BZr6) showed fewer physicochemical factors impacting biocontrol compared to the second interaction (BMp29 vs. BZr6). However, the fewer factors of the first interaction had a stronger effect on the decline in the spoilage population. Validations showed that the optimal conditions for biocontrol with the first interaction could be predicted. Analysis of the results with BWa156 vs. BZr6 and BMp29 vs. BZr6 suggests that the first interaction is a competition that includes a killer toxin, while the second interaction involves competition for iron resources. Response surface methodology (RSM) allowed a reduction in the number of experiments and permitted to find the optimal biocontrol conditions (SO2: 0 mg mL-1; pH: 3.7; Reducing sugars: 23 °Brix) for the interaction between BWa156 and BZr6.Fil: Kuchen, Benjamín. Departamento de Ingenieria Agronomica ; Facultad de Ingenieria ; Universidad Nacional de San Juan; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan; ArgentinaFil: Maturano, Yolanda Paola. Departamento de Ingenieria Agronomica ; Facultad de Ingenieria ; Universidad Nacional de San Juan; ArgentinaFil: Scaglia, Gustavo Juan Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan; Faculta de Ingeniaría; Instituto de Ingeniería Química; ArgentinaFil: Pera, Licia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Vallejo, Martha Dina. Universidad Nacional de San Juan; Argentin

Selection of non-Saccharomyces yeasts to be used in grape musts with high alcoholic potential: A strategy to obtain wine with reduced etanol content

Ethanol content of wine has increased over the last decades as consequence of searching phenolic maturity, requiring increased grape maturity. This may result in the production of wines with excessive alcohol levels (sometimes more than 15% (v/v)), sluggish and stuck fermentations and excessive volatile acidity. Many strategies to reduce ethanol in wines are being studied, and microbial methods have some additional advantages. However, because of the broad intra- and interspecies variability, new selection criteria should be included. Therefore, the goal of the present work was to design and evaluate a simple and integral procedure for non-Saccharomyces yeast selection. This strategy allowed selection of yeasts that presented successful implantation in grape must with high alcohol potential and their use in co-cultures could reduce the ethanol in wines. A total of 114 native non-Saccharomyces yeasts were assayed to determine their respiratory, fermentative and physiological characteristics of enological interest. Hanseniaspora uvarum BHu9 and BHu11, H. osmophila BHo51, Starmerella bacillaris BSb55 and Candida membranaefaciens BCm71 were selected as candidates to design co-culture startersEEA MendozaFil: Mestre Furlani, Maria Victoria. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Maturano, Yolanda Paola. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mercado, Laura Analia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Instituto de Biotecnología; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentin

Monitoring of killer yeast populations in mixed cultures: influence of incubation temperature of microvinifications samples

Killer yeasts are frequently used to combat and prevent contamination by wild-type yeasts during wine production and they can even dominate the wine fermentation. Stuck and sluggish fermentations can be caused by an unbalanced ratio of killer to sensitive yeasts in the bioreactor, and therefore it is important to determine the proportion of both populations. The aim of this study was to provide a simple tool to monitor killer yeast populations during controlled mixed microvinifications of killer and sensitive Saccharomyces cerevisiae. Samples were periodically extracted during vinification, seeded on Petri dishes and incubated at 25 and 37 °C; the latter temperature was assayed for possible inactivation of killer toxin production. Colonies developed under the described conditions were randomly transferred to killer phenotype detection medium. Significant differences in the killer/sensitive ratio were observed between both incubation temperatures in all microvinifications. These results suggest that 37 °C seems a better option to determine the biomass of sensitive yeasts, in order to avoid underestimation of sensitive cells in the presence of killer yeasts during fermentations. Incubation at a toxin-inhibiting temperature clearly showed the real ratio of killer to sensitive cells in fermentation systems.Fil: Maturano, Yolanda Paola. Universidad Nacional de San Juan. Instituto de Biotecnología; ArgentinaFil: Nally, María Cristina. Universidad Nacional de San Juan. Instituto de Biotecnología; ArgentinaFil: Toro, María Eugenia. Universidad Nacional de San Juan. Instituto de Biotecnología; ArgentinaFil: Castellanos de Figueroa, Lucía Inés. PROIMI; Argentina. Universidad Nacional de Tucumán. FBQyF; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentin

Free Volatile Compounds of cv. Pedro Giménez (Vitis vinifera L.) White Grape Must Grown in San Juan, Argentina

The free aromatic composition of must from Pedro Giménez grapes, grown in San Juan, Argentina, was characterised. Samples from the vintages of 2008 and 2009 were analysed by gas chromatography–mass spectrometry–solid phase microextraction (GC–MS–SPME). Higher alcohols, terpenes, C13-norisoprenoids, esters, aldehydes and ketones were quantified. The calculation of the odour activity values (OAVs) revealed that β-damascenone, α-ionone, β-linalool, geraniol, ethyl butanoate, hexanoate and octanoate were the most prevalent aroma-active compounds of the grape variety. However, the remaining 42 aromatic compounds that registered OAVs less than 1 could potentially contribute to the flavour of Pedro Giménez grapes. The measured monoterpene levels indicate that the Pedro Giménez grape can be considered a neutral variety. This is the first report describing the main potential free aroma contributors of Pedro Giménez grapes in two consecutive years.EEA MendozaFil: Maturano, Yolanda Paola. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nally, María Cristina. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Assof, Mariela Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza. Laboratorio de Aromas y Sustancias Naturales; ArgentinaFil: Toro, María Eugenia. Universidad Nacional de San Juan. Instituto de Biotecnología; ArgentinaFil: Castellanos de Figueroa, Lucía Inés. PROIMI; Argentina. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jofre, Viviana Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza. Laboratorio de Aromas y Sustancias Naturales; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Instituto de Biotecnología; Argentin

Bioprospecting of the probiotic potential of yeasts isolated from a wine environment

Autochthonous yeasts of oenological origin are adapted to highly stressful and selective environments, which makes them potential candidates for probiotics. The objective of the present study was to explore the probiotic potential of 96 native yeasts of oenological origin, their biosafety, resistance to gastrointestinal tract conditions and adhesion properties. Regarding biosafety, 66 isolates shown negative hemolytic activity, negative urease activity and susceptibility to 3 or more antifungals. After the gastrointestinal resistance test, 15 isolates were selected that showed growth at different temperatures, tolerance to low pH and the presence of bile salts in in vitro tests. In general, survival after simulated conditions of the gastrointestinal tract was high and more restrictive was the duodenal. The results of the adhesion properties showed highly variable hydrophobicity and a high percentage of autoaggregation at 24 h. The maximum production of biofilm was detected in the Pichia strains. Of a total of 96 yeast strains, 15 non-Saccharomyces yeasts presented suitable properties as probiotic candidates. The native winemaking strains performed better than the reference probiotic strain, Saccharomyces cerevisiae var. boulardii CNCM I-745, which reaffirms that these strains are promising probiotic candidates and further studies are necessary to confirm their probiosis.Fil: Vergara Alvarez, Silvia Cristina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Leiva Alaniz, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Mestre Furlani, María Victoria. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Mancha Agresti, Pamela. Centro Federal de Educação Tecnológica; BrasilFil: Cristina Nally, María. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Maturano, Yolanda Paola. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin