Overexpression of different alcohol acetyltransferase genes with BAT2 deletion in Saccharomyces cerevisiae affects acetate esters and higher alcohols

Abstract

Acetate esters and higher alcohols significantly determine the flavor profiles of Chinese Baijiu (Chinese liquor). The aminotransferase encoded by BAT2 and alcohol acetyltransferases encoded by ATF1, ATF2, and Lg-ATF1 are involved in the production of branched-chain alcohols and synthesis of acetate esters, respectively. In this study, the effects of ATF1, ATF2, and Lg-ATF1 overexpressions with BAT2 deletion were explored in Chinese Baijiu yeast. The differences among these effects were also investigated. Results showed that the productions of acetate esters by mutant overexpressing ATF1 with BAT2 deletion and that overexpressing ATF2 with BAT2 deletion were 1353.45 and 73.40 mg/L, respectively, which were 43.16- and 2.34-fold higher than that by the original strain. Compared with mutant overexpressing ATF2 with BAT2 deletion, mutant overexpressing ATF1 with BAT2 deletion exhibited 48.17% decreased higher alcohol productivity. The production of higher alcohols in mutant overexpressing ATF2 with BAT2 deletion was similar to that in the BAT2 deletion mutant. Furthermore, no significant difference was observed between the BAT2 deletion mutant and the mutant overexpressing Lg-ATF1 with BAT2 deletion in terms of acetate ester and higher alcohol production. The mutants that have varying capacities for acetate ester and higher alcohol production can be potentially developed and applied.