合成硒代谷胱甘肽酿酒酵母菌株的筛选与发酵优化

Screening and Fermentation Optimization of Saccharomyces cerevisiae Strains for Selenoglutathione Synthesis

以实验室保存的19株酿酒酵母为出发菌株,通过亚硒酸钠抗性筛选、耐硒驯化、硫酸二乙酯诱变、乙硫氨酸抗性筛选,成功得到一株能合成硒代谷胱甘肽的酿酒酵母菌株CMY-15-1,其有机硒含量达到2 663.3μg/g。单因素试验确定CMY-15-1最佳发酵条件,在该条件下筛选出碳源、有机氮源和无机氮源、无机盐等成分,并优化亚硒酸钠添加量。通过Plackett-Burman设计试验筛选出对CMY-15-1产硒代谷胱甘肽显著性影响成分。通过最陡爬坡试验,确定培养基中组分的添加量,由中心复合设计试验得到最佳发酵培养基组成,蛋白胨5.46 g/L、亚硒酸钠205.9 mg/L、氯化铵9.56 g/L、葡萄糖35 g/L、酵母粉8 g/L、磷酸氢二钾0.5 g/L、氯化镁0.5 g/L、氯化钙0.5 g/L,测得硒代谷胱甘肽含量为33.71μg/L,优化后的硒代谷胱甘肽产量是优化前的3.94倍左右。

In this experiment,19 strains of Saccharomyces cerevisiae stored in the laboratory were selected as the starting strains. Strain CMY-15-1,which can synthesize selenoglutathione,was successfully obtained by screening sodium selenite resistance,selenium resistance acculturation,diethyl sulfate mutagenesis,and ethylthiocyanine resistance. The organic selenium content of CMY-15-1 reached 2 663.3 μg/g. The optimum fermentation conditions of CMC-15-1 were determined by single factor test by screening out carbon,organic nitrogen,and inorganic nitrogen sources and inorganic salt,and the supplemental amount of sodium selenite was optimized. Plackett-Burman designs were used to screen out the significant components affecting the selenoglu-tathione production of CMY-15-1. Through the steepest ascent test,the addition amount of components in the medium was determined,and the optimal fermentation medium was obtained by central composite design. The content of selenoglutathione was 33.71 μg/L with peptone 5.46 g/L,sodium selenite 205.9 mg/L,ammonium chloride 9.56 g/L,glucose 35 g/L,yeast 8 g/L,dipotassium hydrogen phosphate 0.5 g/L,magnesium chloride 0.5 g/L,and calcium chloride 0.5 g/L. The yield of Se glutathione after optimization was approximately 3.94 times that before optimization.