Hydrogen sulfide synthesis in native Saccharomyces cerevisiae strains during alcoholic fermentations

In order to diminish the undesirable impact of hydrogen sulfide (H2S) on wine, H2S synthesis was evaluated at phenotypic and transcriptional levels in 16 strains of Saccharomyces cerevisiae, which comprised 12 natural isolates, three commercial strains, and one laboratory heterozygote. Strain-dependent and multi-gene participation traits were evident, and high gene activity did not necessarily elevated H2S levels. When the variation of gene expression was analyzed between fermentation stages in each strain, similarities among some strains related to H2S formation. UCD522 and seven strains with low H2S production were grouped together based on cluster analysis and fold-change analysis. They displayed a negative relationship between activity of MET17, HOM2, SER33 and CYS4 and H2S formation, suggesting the role of biosynthesis of sulfur-containing amino acids. In the CECLFE1225, CECLFE1226 and UCD819 strains, transcriptional variation in MET3, MET5 and MET10 might account for the changes in H2S amount. High levels of HOM2 and SER33 expression were implicated with the H2S phenotype of CECGM1 (H2S-free strain). MET1 may be a key gene in sulfide biosynthesis owing to its involvement in almost all strains. This study furthers the understanding of H2S formation in different S. cerevisiae strains and the industrial application of natural isolates.