Effect of the Deletion of Genes Related to Amino Acid Metabolism on the Production of Higher Alcohols by Saccharomyces cerevisiae.

The higher alcohols produced by Saccharomyces cerevisiae exert remarkable influence on the taste and flavour of Chinese Baijiu. In order to study the regulation mechanism of amino acid metabolism genes on higher alcohol production, eight recombinant strains with amino acid metabolism gene deletion were constructed. The growth, fermentation performance, higher alcohol production, and expression level of genes in recombinant and original α5 strains were determined. Results displayed that the total higher alcohol concentration in α5ΔGDH1 strain decreased by 27.31% to 348.68 mg/L compared with that of α5. The total content of higher alcohols in α5ΔCAN1 and α5ΔGAT1 strains increased by 211.44% and 28.36% to 1493.96 and 615.73 mg/L, respectively, compared with that of α5. This study is the first to report that the CAN1 and GAT1 genes have great influence on the generation of higher alcohols. The results demonstrated that amino acid metabolism plays a substantial role in the metabolism of higher alcohols by S. cerevisiae. Interestingly, we also found that gene knockout downregulated the expression levels of the knocked out gene and other genes in the recombinant strain and thus affected the formation of higher alcohols by S. cerevisiae. This study provides worthy insights for comprehending the metabolic mechanism of higher alcohols in S. cerevisiae for Baijiu fermentation.