Effect of ILV2 deletion and ILV3 or/and ILV5 overexpression in Saccharomyces uvarum on diacetyl and higher alcohols metabolism during wine fermentation

Diacetyl and higher alcohols, as the crucial flavour compounds, have been found to associate with the sensory properties of the wine. The genes ILV2, ILV3 and ILV5 in isoleucine-valine (ILV) biosynthetic pathway related to diacetyl and higher alcohols have been reported in Saccharomyces cerevisiae, whereas the regulatory mechanism in Saccharomyces uvarum is still unclear. The current study explored that ILV2 deletion and ILV3 or/and ILV5 overexpression in S. uvarum resulted in significant changes in the diacetyl and higher alcohols production. And of all the mutant strains, 3QV2 + V35 (ILV2 triple-gene-deletion with ILV3 + ILV5 overexpression), in which the diacetyl, isobutanol, and isoamyl alcohol contents were reduced by 67.56%, 25.46% and 21.05%, respectively, presented the most effective effect on regulation of diacetyl and higher alcohols production in wine. This study provided a valuable reference for further research on diacetyl and higher alcohol metabolism in S. uvarum and future optimization of yeast strains for wine and other alcoholic beverages.