富硒酵母菌的筛选及其富硒条件的优化

Screening and Optimized Culture of Selenium-enriched Saccharomyces cerevisiae

[目的]选育高富硒酵母菌株,优化发酵培养条件,以提高酵母生物富集、转化有机硒的能力。[方法]以耐受亚硒酸钠强的菌株为出发菌株,研究该菌株在培养过程中的亚硒酸钠添加量、添加时间、酵母菌接种龄、培养温度等参数,从而达到最优的酵母生物量及富硒量。[结果]研究表明,酵母菌FX5菌株具有较高的耐受性和富硒能力。发酵条件优化表明,FX5菌株在亚硒酸钠添加量为20 g/L、添加硒的时间为6 h,富硒效果最好。在最佳的摇瓶培养条件下(初始硒浓度20μg/mL,接种量10%,装液量50/250 mL,温度28℃,初始pH 6.0,摇床转速160 r/min,接种龄84 h,培养60 h后),该酿酒酵母的生物量及富硒量分别达到40.1 g/L、1 120 mg/L。[结论]该研究可为富硒农牧业生产提供一种安全的有机硒源。

[Objective]To select high selenium enriched yeast strains and optimize fermentation conditions to improve yeast bioaccumulation and transformation ability of organic selenium.[Method]With sodium selenite tolerance strong strain as the starting strain, the strain in the training process of sodium selenite adding amount and adding time, yeast inoculation age, culture temperature and other parameters, so as to achieve the optimal amount of biomass and selenium enriched yeast.[ Result] The results showed that yeast FX5 strain had high tolerance and selenium accumulation ability.The optimization of fermentation conditions showed that the addition of sodium selenite was 20 g/L and the time of adding selenium was 6 h, and the effect of selenium enrichment was best for FX5 strain.In the best shake flask culture conditions （ initial selenium concentration 20 g/mL, inoculum size 10%, medium volume 50/250 mL, temperature 28 ℃, initial pH 6, rotation speed of 160 r/min, 84 h age of inoculation, after cultured for 60 h）, biomass and Se content of the yeast were respectively 40.1 g/L, 1120 mg/L. [ Conclusion] The study can provide a safe organic selenium source for the production of selenium enriched agriculture and animal husbandry.