高产谷胱甘肽酿酒酵母菌株的诱变选育研究

Mutation Breeding High-yield Glutathione Strains of Saccharomy cerevisiae

考察了半胱氨酸(CYS)添加量和添加时间对酿酒酵母(Saccharomy cerevisiae Y08)合成谷胱甘肽(GSH)的影响。结果表明:在发酵开始时添加半胱氨酸,能够增强菌体合成GSH能力,当添加量达到0.05%时,GSH产量达到最大值(52.28mg·L-1)。在发酵稳定期(10h)添加半胱氨酸,胞内GSH含量增加不显著,GSH产量仅提高了10.57%。为降低半胱氨酸对菌体生长的抑制,对酿酒酵母原生质体进行复合诱变,筛选半胱氨酸抗性突变菌株。结果表明:半胱氨酸对半胱氨酸抗性突变菌株的生长抑制作用减轻,抗性菌株能够在含有0.4%半胱氨酸的发酵液中正常生长,GSH产量和胞内GSH含量比未加半胱氨酸时均有显著提高,分别提高了29.28%和29.64%,且性状稳定。

Effects of cysteine （CYS） content and its adding time on glutathione synthesized by Saccharomy cerevisiae Y08 were studied. Results showed that CYS could increase to synthesize GSH in the beginning of the fermentation, and GSH yield could reach 52.28 mg·L^-1 when CYS dosage was 0.05%. Intracellular GSH content did not increase significantly in the stable period of fermentation （10h）,and GSH yield only increased by 10.57%. To reduce cysteine inhibition on cells growth, cysteine resistant mutant strains were screened by composite protoplast mutagenesis. Results showed that cysteine inhibition was reduced and cells could grow in the fermentation broth containing 0.4% cysteine, while GSH yield and intracellular GSH content significantly increased by 29.28% and 29.64% respectively and had stable traits, compared to that without cysteine.