Acetate ester, which are produced by fermenting yeast
cells in an enzyme-catalyzed intracellular reaction, are responsible for
the fruity character of fermented alcoholic beverages such as Chinese
yellow rice wine. Alcohol acetyltransferase (AATase) is currently
believed to be the key enzyme responsible for the production of
acetate ester. In order to determine the precise role of the ATF2 gene
in acetate ester production, an ATF2 gene encoding a type of AATase
was overexpressed and the ability of the mutant to form acetate esters
(including ethyl acetate, isoamyl acetate, and isobutyl acetate) was
investigated. The results showed that after 5 days of fermentation, the
concentrations of ethyl acetate, isoamyl acetate, and isobutyl acetate
in yellow rice wines fermented with EY2 (pUC-PIA2K) increased to
137.79 mg/L (an approximate 4.9-fold increase relative to the parent
cell RY1), 26.68 mg/L, and 7.60 mg/L, respectively. This study confirms
that the ATF2 gene plays an important role in the production of acetate
ester production during Chinese yellow rice wine fermentation, thereby