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.