Exploring Proteomic and Metabolomic Interactions in a Yeast Consortium Designed to Enhance Bioactive Compounds in Wine Fermentations

Abstract

There is a new trend in modern oenology to inoculate more than one yeast strain in order to increase microbial diversity and respond to some of the new demands of the wine market. The presence of bioactive molecules in wine is clearly one of these consumer demands, as it can contribute to the bioactivity, quality, and stability of the final products. As many of these bioactive molecules are a consequence of yeast metabolism, our aim in this study was to increase the concentration of tryptophan-derived indole metabolites using a consortium of two Saccharomyces strains, one Saccharomyces cerevisiae (Sc) and one Saccharomyces uvarum (Su), and to understand the molecular and metabolic mechanisms that led to the enhanced biosynthesis of these molecules. The comparison of the proteome of these two strains growing in pure and co-inoculated fermentation, together with a metabolic study of the final wines, has revealed the main strategies of competence in both species. Both proteomic and metabolomic data indicated that the presence of a competitive strain in the same fermentation medium accelerated the growth rate of Sc, upregulated protein translation and ribosome formation, whereas it enhanced the production of bioactive molecules derived from tryptophan in Su, which showed a natural enrichment in metabolites of aromatic amino acid biosynthesis pathway. This study confirmed the idea of combining yeast strains and species as an oenological tool to produce wines of different quality and the need to study the mechanisms of interaction between strains in order to predict the final results.