采用新型药物抗性选育高效黄酒酵母菌株

Breeding high-efficiency Chinese rice wine yeast by a new drug resistance strategy

摘要:

【目的】黄酒酵母菌种是影响大罐黄酒生产效率的关键因素之一，高发酵性能黄酒酵母的选育对于提升黄酒生产效率具有重要的实用意义。【方法】以一种药物抗性为基础设计快速初筛方法，对黄酒酿酒酵母XY进行诱变筛选得到克霉唑(CTZ)抗性的黄酒酵母突变株，进一步以酵母发酵性参数为指标筛选得到发酵速率提高的黄酒酵母新菌株XY-3。【结果】比较突变菌株与原始菌株酿造性能发现，XY-3菌株最大发酵速率较原始菌株提高5.21%。黄酒酿造小试结果显示发酵前4天XY-3菌株乙醇生成速率明显高于原始菌株，其最大乙醇生成速率从XY菌株的14.77 g/d提高到15.30 g/d。XY-3酵母菌株发酵速率的提高能够缩短黄酒发酵周期1?2天，有助于提高发酵设备的利用效率。进一步研究发现XY-3发酵速率的提升可能与XY-3菌株多药物抗性(PDR)有关。【结论】联合使用传统诱变和药物抗性筛选策略选育得到高效黄酒酵母新菌株，这种筛选策略也为发酵食品行业优良菌株的选育提供了一种新的思路。

Abstract:

[Objective] High fermentation efficiency is desirable for Saccharomyces cerevisiae used in the Chinese rice wine brewing. In this study, we developed a drug resistance screening protocol to obtain a Chinese rice wine yeast strain with higher fermentation efficiency. [Methods] Clotrimazole (CTZ)-resistant strains of S. cerevisiae were isolated from the parent Chinese rice wine yeast strain. Then fermentation power, fermentation rate, and brewing property were used to screen mutants with higher fermentation efficiency compared with the parent. [Results] A total of 18 stable CTZ-resistant mutants were obtained through UV mutagenesis from Chinese rice wine yeast strain XY. In these 18 CTZ-resistant mutants, strain XY-3 gave a 5.21% higher max-fermentation rate than that of the strain XY by flask fermentation tests. In lab-scale Chinese rice wine brewing, strain XY-3 (15.30 g/d) also showed a higher maximum fermentation rate than that of strain XY (14.77 g/d), leading to shorter fermentation period of Chinese rice wine brewing by 1–2 days. [Conclusion] Combining traditional mutation with CTZ-resistant screening protocol was an efficient approach to screen Chinese rice wine yeasts with higher fermentation efficiency.