Effects of overexpression of the alcohol acetyltransferase‐encoding gene ATF1 and disruption of the esterase‐encoding gene IAH1 on the flavour profiles of Chinese yellow rice wine

Abstract

SummaryAlcohol acetyltransferase (AATase), which is mainly encoded by ATF1, is one of the most important enzymes for acetate ester synthesis. On the other hand, isoamyl acetate is degraded into a higher alcohol under the catalysis of IAH1‐encoded esterase. In this study, Chinese Saccharomyces cerevisiae was used as the parent strain to construct an ATF1 overexpression and IAH1 disruption mutant. The results show that after 5 days of pre‐fermentation, the concentrations of ethyl acetate, isoamyl acetate and isobutyl acetate in the yellow rice wines fermented with EY1 (pUC‐PIAK) increased to 468.94 mg L−1 (which is approximately 22‐fold higher than that of the parent cell RY1), 99.86 and 7.69 mg L−1 respectively. Meanwhile, isoamyl alcohol production was reduced to 56.37 mg L−1 (which is approximately 50% of that produced by the parent strain RY1). Therefore, ATF1 overexpression and IAH1 disruption can significantly increase acetate esters contents and reduce isoamyl alcohol content in Chinese yellow rice wine, thereby paving the way for breeding an excellent yeast strain for high‐quality Chinese yellow rice wine production.