Alcoholic fermentation is generally performed by Saccharomyces spp., especially by the principal wine yeast Saccharomyces cerevisiae. The wide variety of natural yeasts reflects the biodiversity, in most grape musts. During spontaneous fermentation, dynamics of microbial population results in successions of different strains, which contribute to the aromatic complexity and diversity of the wine. In the present work, Saccharomyces cerevisiae strains were isolated in 2009 during the harvest from biodynamic wine farms of Tuscany, starting from Syrah musts with zero or low levels of added sulphite, according to the tendency of “natural wines” producers to abate every invasive operation during wine making. By means of molecular techniques, thirteen different profiles of Saccharomyces cerevisiae strains were identified from a hundred isolates. The collected Saccharomyces cerevisiae strains were characterized, in order to verify the effect of low sulphite addition on biodiversity, pursuing information about stress-adaptation mechanisms that allow the survival in the challenging environment of fermenting must. Sulphite addition may act as a selective factor to induce the presence and the activity of strains with diverse features about sulphite metabolism. The different additions of sulphite induced a considerable variability among strains. Moreover, increasing levels of ethanol limited considerably the activity of the selected strains. Further gene-specific investigation may contribute to reveal the complex mechanism of resistance to environmental stress condition.
Autori interni: | |
Autori: | Labagnara, Tilde; GIAN PIETRO, Carrozza; Toffanin, Annita |
Titolo: | Biodiversity of wine yeast in response to environmental stress |
Anno del prodotto: | 2014 |
Abstract: | Alcoholic fermentation is generally performed by Saccharomyces spp., especially by the principal wine yeast Saccharomyces cerevisiae. The wide variety of natural yeasts reflects the biodiversity, in most grape musts. During spontaneous fermentation, dynamics of microbial population results in successions of different strains, which contribute to the aromatic complexity and diversity of the wine. In the present work, Saccharomyces cerevisiae strains were isolated in 2009 during the harvest from biodynamic wine farms of Tuscany, starting from Syrah musts with zero or low levels of added sulphite, according to the tendency of “natural wines” producers to abate every invasive operation during wine making. By means of molecular techniques, thirteen different profiles of Saccharomyces cerevisiae strains were identified from a hundred isolates. The collected Saccharomyces cerevisiae strains were characterized, in order to verify the effect of low sulphite addition on biodiversity, pursuing information about stress-adaptation mechanisms that allow the survival in the challenging environment of fermenting must. Sulphite addition may act as a selective factor to induce the presence and the activity of strains with diverse features about sulphite metabolism. The different additions of sulphite induced a considerable variability among strains. Moreover, increasing levels of ethanol limited considerably the activity of the selected strains. Further gene-specific investigation may contribute to reveal the complex mechanism of resistance to environmental stress condition. |
Appare nelle tipologie: | 1.1 Articolo in rivista |
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