Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, NO.1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China.
Laboratory of Brewing Science and Engineering, Jiangnan University, Wuxi, 214000, China.
World J Microbiol Biotechnol. 2021 Jun 26;37(7):125. doi: 10.1007/s11274-021-03082-7.
Ethyl-acetate is important for the flavor and aroma of the alcoholic beverages, therefore, there have been extensive efforts toward increasing its production by engineering yeast strains. In this study, we reported a new approach to breed non-genetic modified producing yeast strain with higher ethyl-acetate production for beer brewing. First, we demonstrated the positive effect of higher acetic acid concentration on inducing the expression of acetyl-CoA synthetase (ACS). Then, we applied adaptive laboratory evolution method to evolve strain with higher expression level of ACS. As a result, we obtained several evolved strains with increased ACS expression level as well as ethyl-acetate production. In 3 L scale fermentation, the optimal strain EA60 synthesized more ethyl-acetate than M14 at the same time point. At the end of fermentation, the ethyl-acetate production in EA60 was 21.4% higher than M14, while the other flavor components except for acetic acid were changed in a moderate degree, indicating this strain had a bright prospect in industrial application. Moreover, this study also indicated that ACS1 played a more important role in increasing the acetic acid tolerance of yeast, while ACS2 contributed to the synthesis of cytosol acetyl-CoA, thereby facilitating the production of ethyl-acetate during fermentation.
乙酸乙酯对酒精饮料的风味和香气很重要，因此，人们一直在努力通过工程酵母菌株来提高其产量。在这项研究中，我们报道了一种新的方法，用于培育具有更高产乙酸乙酯能力的非遗传修饰啤酒酿造用生产酵母菌株。首先，我们证明了较高的乙酸浓度对诱导乙酰辅酶 A 合成酶 (ACS) 表达的积极影响。然后，我们应用适应性实验室进化方法来进化具有更高 ACS 表达水平的菌株。结果，我们获得了几个具有更高 ACS 表达水平和乙酸乙酯产量的进化菌株。在 3 L 规模的发酵中，最优菌株 EA60 在相同的时间点合成的乙酸乙酯比 M14 多。在发酵结束时，EA60 中的乙酸乙酯产量比 M14 高 21.4%，而除乙酸以外的其他风味成分变化适中，表明该菌株在工业应用中有广阔的前景。此外，本研究还表明，ACS1 在提高酵母对乙酸的耐受性方面起着更重要的作用，而 ACS2 有助于细胞质乙酰辅酶 A 的合成，从而有利于发酵过程中乙酸乙酯的生成。
