Saccharomyces cerevisiae wine yeast populations in a cold region in Argentinean Patagonia. A study at different fermentation scales

Abstract

Aims: To study the diversity and dynamics of indigenous Saccharomyces wine populations during Malbec spontaneous fermentation, a representative Patagonian red wine, at both industrial and laboratory scale. Methods and Results: Two molecular techniques, including restriction fragment length polymorphism of mitochondrial (mt) DNA and polymorphism of amplified δ interspersed element sequences, were used for characterization of indigenous yeasts at strain level. The mtDNA restriction patterns showed the major discriminative power; however, by combining the two molecular approaches it was possible to distinguish a larger number of strains and, therefore, draw more representative conclusions about yeast diversity. Although a great diversity of wild Saccharomyces cerevisiae strains was observed, only nine represented more than half of the total Saccharomyces yeast biota analysed; five of these were common and took over the Malbec must fermentation in both vinifications. Conclusions: Many different indigenous S. cerevisiae strains were identified; nevertheless, the dominant strains in both industrial and laboratory vinification processes were just a few and the same. Significance and Impact of the Study: Small-scale fermentation appears to be a valuable tool in winemaking, one especially helpful in evaluating microbiological aspects of as well as possible interactions between inoculated selected strains and native strains.