Research Institute, Gekkeikan Sake Co., Ltd., 101 Shimotoba-koyanagi-cho, Fushimi-ku, Kyoto 612-8385, Japan.
Research Institute, Gekkeikan Sake Co., Ltd., 101 Shimotoba-koyanagi-cho, Fushimi-ku, Kyoto 612-8385, Japan.
J Biosci Bioeng. 2022 Feb;133(2):140-145. doi: 10.1016/j.jbiosc.2021.11.001. Epub 2021 Nov 20.
4-Vinylguaiacol (4-VG) is one of the most common off-flavors found in sake. 4-VG is produced from its precursor, ferulic acid, which is a component of the cell wall of the rice endosperm. The release of ferulic acid in sake brewing is thought to be mediated by feruloyl esterase produced by either Aspergillus oryzae or Saccharomyces cerevisiae. To investigate the effect of FaeA, a feruloyl esterase produced by A. oryzae, its loss-of-function strain was produced by genome co-editing. The feruloyl esterase activity of the faeA-deficient strain was drastically reduced. Sake was fermented using koji with S. cerevisiae strain G046, which can convert ferulic acid to 4-VG. Fermented sake was analyzed by measuring the 4-VG content and sensory evaluation. 4-VG content was reduced to approximately 10% of that of sake fermented with control koji. Sensory evaluation revealed that 4-VG was almost undetectable. Our findings showed that disruption of faeA in A. oryzae is a promising strategy to reduce 4-VG off-flavors in sake.
4-乙烯基愈创木酚（4-VG）是清酒中最常见的异味之一。4-VG 是由其前体阿魏酸产生的，阿魏酸是稻米胚乳细胞壁的组成部分。人们认为，在清酒酿造过程中，阿魏酸的释放是由米曲霉或酿酒酵母产生的阿魏酸酯酶介导的。为了研究由米曲霉产生的阿魏酸酯酶 FaeA 的作用，通过基因组共编辑生产了其功能丧失菌株。faeA 缺陷菌株的阿魏酸酯酶活性大大降低。使用含有酿酒酵母菌株 G046 的曲霉菌进行清酒发酵，该菌株可以将阿魏酸转化为 4-VG。通过测量 4-VG 含量和感官评价来分析发酵后的清酒。与用对照曲霉菌发酵的清酒相比，4-VG 含量降低到约 10%。感官评价表明，4-VG 几乎无法检测到。我们的研究结果表明，敲除米曲霉中的 faeA 是降低清酒 4-VG 异味的一种很有前途的策略。
