Analysis of genes from Saccharomyces cerevisiae HJ01 participating in aromatic alcohols biosynthesis during huangjiu fermentation.

Aromatic alcohols (including β-phenylethanol, tyrosol and tryptophol) could contribute positively to the aroma flavor of huangjiu at an appropriate amount. In this study, it was found that the aromatic alcohols in huangjiu were predominantly synthesized by Saccharomyces cerevisiae HJ01. The Ehrlich pathway and shikimate pathway, including 31 genes, are responsible for aromatic alcohol biosynthesis in S. cerevisiae. During the first 120 h of huangjiu fermentation, the genes GAP1 HJ01 (permease), BAT2 HJ01 (transaminase), PDC1 HJ01 and PDC5 HJ01 (pyruvate decarboxylase), and ADH1 HJ01 (alcohol dehydrogenase) formed integrated Ehrlich pathway are responsible for aromatic alcohol biosynthesis. In S. cerevisiae HJ01, the mutations in the promoter region of genes GAP1 HJ01, BAT2 HJ01, PDC1 HJ01, and PDC5 HJ01 involved in the Ehrlich pathway increased the promoter strength and transcriptional levels of related genes. The addition of 20 U/g acid protease could substantially increase the expression levels of genes involved in the Ehrlich pathway, and therefore there were 34.7% increasing for the concentration of total aromatic alcohols. • Aromatic alcohols in huangjiu are synthesized by Saccharomyces cerevisiae. • Aromatic alcohols in huangjiu are mainly synthesized through the Ehrlich pathway. • Key genes and promoter mutations in Ehrlich pathway were identified. • Acid protease enhanced expression level of key genes. [ABSTRACT FROM AUTHOR]