Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
Appl Biochem Biotechnol. 2013 Feb;169(3):1016-25. doi: 10.1007/s12010-012-0077-y. Epub 2013 Jan 9.
Higher acetaldehyde concentration in beer is one of the main concerns of current beer industry in China. Acetaldehyde is always synthesized during beer brewing by the metabolism of yeast. Here, using ethanol as the sole carbon source and 4-methylpyrazole as the selection marker, we constructed a new mutant strain with lower acetaldehyde production and improved ethanol tolerance via traditional mutagenesis strategy. European Brewery Convention tube fermentation tests comparing the fermentation broths of mutant strain and industrial brewing strain showed that the acetaldehyde concentration of mutant strain was 81.67 % lower, whereas its resistant staling value was 1.0-fold higher. Owing to the mutation, the alcohol dehydrogenase activity of the mutant strain decreased to about 30 % of the wild-type strain. In the meantime, the fermentation performance of the newly screened strain has little difference compared with the wild-type strain, and there are no safety problems regarding the industrial usage of the mutant strain. Therefore, we suggest that the newly screened strain could be directly applied to brewing industry.
啤酒中较高的乙醛浓度是当前中国啤酒行业的主要关注点之一。乙醛在啤酒酿造过程中总是由酵母代谢合成的。在这里，我们使用乙醇作为唯一的碳源和 4-甲基吡唑作为选择标记，通过传统的诱变策略构建了一个新的突变株，该突变株具有较低的乙醛产量和提高的乙醇耐受性。通过欧洲酿造协会管发酵试验比较突变株和工业酿造菌株的发酵液，发现突变株的乙醛浓度降低了 81.67%，而其抗老化值提高了 1.0 倍。由于突变，突变株的醇脱氢酶活性降低到野生型菌株的约 30%。同时，新筛选的菌株的发酵性能与野生型菌株相比几乎没有差异，而且突变株的工业使用不存在安全问题。因此，我们建议可以直接将新筛选的菌株应用于酿造工业。
