Hydrogen sulfide and its roles in Saccharomyces cerevisiae in a winemaking context

Abstract

The rotten-egg odour of hydrogen sulfide (H₂S) produced by the yeast Saccharomyces cerevisiae has attracted considerable research interest due to its huge impact on the sensory quality of fermented foods and beverages. To date, the yeast genetic mechanisms of H₂S liberation during wine fermentation are well understood and yeast strains producing low levels of H₂S have been developed. Studies have also revealed that H₂S is not just a by-product in the biosynthesis of the sulfur-containing amino acids, but indeed a vital molecule involved in detoxification, population signalling and extending cellular life span. Moreover, polysulfides have recently emerged as key players in signalling and the sensory quality of wine because their degradation leads to the release of H₂S. This review will focus on the recent findings on the production of H₂S and polysulfides in S. cerevisiae and summarise their potential roles in yeast survival and winemaking. Recent advances in techniques for the detection of H₂S and polysulfides offer an exciting opportunity to uncover the novel genes and pathways involved in their formation from different sulfur sources. This knowledge will not only provide further insights into yeast sulfur metabolism, but could potentially improve the sensory quality of wine.