耐酒精酿酒酵母大气压等离子体诱变条件的建立及选育

Establishment of the Conditions of Atmospheric Plasma-Inducing Mutation of S.cerevisiae and Breeding of an Ethanol-Tolerant Strain

酿酒酵母在酒类发酵过程中起着非常重要的作用,但普遍存在耐酒精能力弱、发酵速度慢等问题。本研究采用大气压等离子体技术对酿酒酵母进行诱变,以酵母菌株S1为出发菌株,以致死率和正突变率为指标,对酵母菌菌龄、酵母菌浓度、辐照电压、辐照时间、样品与等离子电极间距和氩气流速等影响大气压等离子诱变的因素进行研究,并通过TTC显色反应、耐酒精性能测定、遗传稳定性实验、糖类发酵实验、致死温度测定、耐高糖度测定、产酯能力测定等对突变酵母进行筛选。确立了酿酒酵母大气压等离子体诱变的最佳条件为:酵母菌菌龄为12 h、酵母菌浓度为106个/m L、辐照电压为165 V、辐照时间为14 min,样品与等离子电极间距为4 cm和氩气流速为1.0 L/h,最终筛选得到1株综合性能较强的突变酵母菌株S45。

S.cerevisiae plays an important role in alcoholic fermentation process, however, it has the problems such as poor alcohol tolerance and slow fermenting rate. In this study, atmospheric plasma-inducing mutation was adopted, S.cerevisiae strain S1 was used as original strain, fatality rate and positive mutation rate was used as the evaluating indexes, and the influencing factors including the age of S.cerevisiae, the con- centration of S.cerevisiae suspension, irradiation voltage, irradiation time, the distance from the electrode to samples, and argon airflow speed etc. were investigated. Afterwards, the mutant strains were screened out through TTC color reaction, alcohol resistance determination, genetic stability test, sugar fermentation test, fatal temperature determination, high glucose tolerance test and esters-producing capacity test. The optimal atmospheric plasma-inducing mutation conditions were determined as follows： the age of S.cerevisiae was 12 h, the concentration of S.cere-visiae suspension was 106/mL, irradiation voltage was 165 V, irradiation time was 14 min, the distance from the electrode to samples was 4 cm, and argon airflow speed was 1.0 L/h. Finally, a mutant strain S45 with strong ethanol tolerance was obtained.