Downregulation of EHT1 and EEB1 in Saccharomyces cerevisiae Alters the Ester Profile of Wine during Fermentation.

and are the key genes involved in the synthesis of ethyl esters during wine fermentation. We constructed single (, ) and double () heterogenous mutant strains of the industrial diploid wine yeast EC1118 by disrupting one allele of and/or . In addition, the aromatic profile of wine produced during fermentation of simulated grape juice by these mutant strains was also analyzed. The expression levels of and/or in the relevant mutants were less than 50% of the wild-type strain when grown in YPD medium and simulated grape juice medium. Compared to the wild-type strain, all mutants produced lower amounts of ethyl esters in the fermented grape juice and also resulted in distinct ethyl ester profiles. , a gene involved in acetate ester synthesis, was expressed at higher levels in the downregulation mutants compared to the wild-type and strains during fermentation, which was consistent with the content of acetate esters. In addition, the production of higher alcohols was also markedly affected by the decrease in levels. Compared to , downregulation had a greater impact on the production of acetate esters and higher alcohols, suggesting that controlling expression could be an effective means to regulate the content of these aromatic metabolites in wine. Taken together, the synthesis of ethyl esters can be decreased by deleting one allele of and in the diploid EC1118 strain, which may modify the ester profile of wine more subtly compared to the complete deletion of target genes.