Directed metabolomic approaches for the characterization and development of new yeast strains

Abstract

Abstract. Analyzing the influence of different yeast species on several compounds with enological interest, it becomes possible to identify metabolic determinants of the incidence of yeasts on wine quality. Contrary to Saccharomyces cerevisiae, understanding genetic regulation, enzymatic properties and physiology of non-Saccharomyces species in enological conditions is far from being known. Because of this, the commercialization of industrial non-Saccharomyces strains on wine industry is showing a really slow pace. In order to determine the enzymatic properties of wine-related yeast species it is necessary to evaluate hundreds of yeast isolates enabling us to robustly attribute specific enzymatic activities to a specific group of yeast species. The contribution of yeasts to wine flavour is greatly determined by their impact on aromatic compounds release. Different glycosidases, β-lyase, pectinase, cellulase and protease activities are described as responsible for changes in wine composition, so determining inter-and intraspecific variability in these enzymatic properties in yeast species seems to be a useful tool for innovative yeast selection process. With the aim of relating enzymatic activities with a specific impact in wine properties we developed combined fermentations with non-Saccharomyces selected strains and industrial S. cerevisiae strains. The use of rational metabolomic analysis allows us to explain the physiology of non-Saccharomyces yeasts during wine fermentation and its incidence on wine quality.