富含谷氨酸酿酒酵母的筛选及发酵培养基优化

Screening of Saccharomyces cerevisiae with high glutamic acid content and optimization of fermentation medium

从农家自酿葡萄酒中筛选出一株富含谷氨酸酿酒酵母菌(Saccharomyces cerevisiae)F-5,其26S rDNA核苷酸序列与S.cerevisiae TY12的26S rDNA核苷酸序列同源性为100%。以胞内谷氨酸含量为目标,采用响应面法对其发酵培养基进行了优化,建立糖蜜、工业蛋白胨和KH2PO4的二次回归模型,确定培养基最佳配方为:糖蜜(含30%蔗糖)100 mL/L、酵母浸粉10 g/L、工业蛋白胨20 g/L、MgSO_4·7H_2O 1 g/L、KH_2PO_4 0.5 g/L、FeSO_4·7H_2O 2 g/L。在此优化培养基中发酵培养24 h,胞内游离谷氨酸达到了3.29%,比优化前提高了87.8%。

A Saccharomyces cerevisiae F-5 with high glutamic acid content was screened from home-made wine. The homology of its 26S rDNA se- quence with the 26S rDNA sequence of S. cerevisiae TY12 was 100%. Using the intracellular glutamate content as evaluation indexes, the fermenta- tion medium of the strain F-5 was optimized by response surface methodology, and quadratic regression model of molasses, industrial peptone and KH2PO4 was established. The optimum formula of fermentation medium were determined as follows： molasses （30% sucrose） 100 ml/L, yeast extract powder 10 g/L, industrial peptone 20 g/L, MgSO4·7H20 1 g/L, K2HPO4 0.5 g/L, and FeSO4·7H20 2 g/L. The content of intracellular free glutamate was up to 3.29% under the optimum medium at 24 h, which was 87.8% higher than that of before optimization.