Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.
Graduate Institute of Food Science Technology, National Taiwan University, Taipei, Taiwan.
PLoS One. 2019 Feb 14;14(2):e0211356. doi: 10.1371/journal.pone.0211356. eCollection 2019.
Kaoliang is a refreshing fragranced type of Chinese spirits with slight apple fragrance that comes from ethyl acetate (EA). Special aromas are produced by esterification microorganisms, which affect the taste and quality of the wine. In this study, new yeast strains were isolated from yellow water, a by-product during fermentation process. Meanwhile, the optimal culture condition was determined for its growth and EA production. Three new strains, Kazachstaniaexigua, Candida humilis and Saccharomyces cerevisiae were identified from yellow water. Among these strains, S. cerevisiae S5 was the new and dominant strain. Results from response surface methodology showed that S. cerevisiae S5 produced 161.88 ppm of EA, in the medium with 4.91% yeast extract, 9.82% peptone, and 20.91% glucose after 96 hours of cultivation at 27.53°C. GC analysis showed that aroma compounds, such as EA, isoamyl acetate and 2-phenylethanol increased from the sample of optimal condition when compared to the one from initial fermentation condition.
高粱酒是一种清香型的中国白酒，带有淡淡的苹果香气，源于乙酸乙酯（EA）。特殊的香气是由酯化微生物产生的，这会影响到酒的口感和质量。在这项研究中，从黄水（发酵过程中的副产品）中分离出了新的酵母菌株。同时，确定了其生长和 EA 生产的最佳培养条件。从黄水中鉴定出了三种新的酵母菌株，分别是酒香酵母（Kazachstania exigua）、汉逊德巴利酵母（Candida humilis）和酿酒酵母（Saccharomyces cerevisiae）。其中，酿酒酵母 S5 是新的优势菌株。响应面法的结果表明，在 27.53°C 下培养 96 小时后，酵母提取物含量为 4.91%、蛋白胨含量为 9.82%、葡萄糖含量为 20.91%的培养基中，酿酒酵母 S5 可产生 161.88ppm 的 EA。GC 分析表明，与初始发酵条件相比，最优条件下的样品中香气化合物（如 EA、乙酸异戊酯和 2-苯乙醇）的含量增加了。
