Fukuda K, Yamamoto N, Kiyokawa Y, Yanagiuchi T, Wakai Y, Kitamoto K, Inoue Y, Kimura A
Kizakura Sake Brewing Co., Ltd., Fushimi-ku, Kyoto 612-8046, Japan.
Appl Environ Microbiol. 1998 Oct;64(10):4076-8. doi: 10.1128/AEM.64.10.4076-4078.1998.
Isoamyl acetate is synthesized from isoamyl alcohol and acetyl coenzyme A by alcohol acetyltransferase (AATFase) in Saccharomyces cerevisiae and is hydrolyzed by esterases at the same time. We hypothesized that the balance of both enzyme activities was important for optimum production of isoamyl acetate in sake brewing. To test this hypothesis, we constructed yeast strains with different numbers of copies of the AATFase gene (ATF1) and the isoamyl acetate-hydrolyzing esterase gene (IAH1) and used these strains in small-scale sake brewing. Fermentation profiles as well as components of the resulting sake were largely alike; however, the amount of isoamyl acetate in the sake increased with an increasing ratio of AATFase/Iah1p esterase activity. Therefore, we conclude that the balance of these two enzyme activities is important for isoamyl acetate accumulation in sake mash.
乙酸异戊酯由酿酒酵母中的乙醇乙酰转移酶（AATFase）从异戊醇和乙酰辅酶A合成，同时会被酯酶水解。我们推测，这两种酶活性的平衡对于清酒酿造中乙酸异戊酯的最佳产量至关重要。为了验证这一假设，我们构建了具有不同拷贝数的AATFase基因（ATF1）和乙酸异戊酯水解酯酶基因（IAH1）的酵母菌株，并将这些菌株用于小规模清酒酿造。发酵过程以及所得清酒的成分大致相似；然而，清酒中乙酸异戊酯的含量随着AATFase/Iah1p酯酶活性比值的增加而增加。因此，我们得出结论，这两种酶活性的平衡对于清酒醪中乙酸异戊酯的积累很重要。
