γ-聚谷氨酸高产菌株选育及发酵条件优化

Breeding of High-yield γ-polyglutamic Acid Strains and Optimization of Fermentation Conditions

本研究从实验室保藏的产γ-聚谷氨酸地衣芽孢杆菌作为出发菌株,采用60Co-γ射线辐照和ARTP诱变协同复合诱变技术,筛选出了一株γ-聚谷氨酸高产菌株FA-22,产量达20.63g/L。通过对其培养基组分和摇瓶培养条件优化,确定了菌株FA-22的最适发酵培养基组分:L-谷氨酸20.0 g/L、柠檬酸12.0 g/L、甘油90.0 g/L、NH4Cl 7.0 g/L、K2HPO40.5g/L、MgSO4·7H2O 0.5g/L、FeCl3·6H2O 0.04g/L、CaCl2·6H2O 0.15g/L、MnSO4·H2O 0.104g/L,pH值7.5;最佳摇瓶培养条件:接种量10%、转速220r/min、温度37℃,装液量80mL/500mL、发酵周期72h;在此条件下,γ-聚谷氨酸产量达32.53g/L,较优化前产量提升了57.68%,为后期的中试发酵奠定了良好的基础。

In this study,theγ-polyglutamic acid-producing Bacillus licheniformis in the laboratory was used as the starting strain,using 60Coγray irradiation and ARTP mutagenesis combined mutagenesis technology to screen a high-yieldingγ-polyglutamic acid strain FA-22,with a yield of 20.63 g/L.By optimizing its medium components and shaking flask culture conditions,the optimum fermentation medium components of strain FA-22 were determined:L-glutamic acid 20.0g/L,citric acid 12.0g/L,glycerol 90.0g/L,NH4Cl 7.0g/L,K2HPO40.5g/L,MgSO4·7H2O 0.5 g/L,FeCl3·6H2O 0.04 g/L,CaCl2·6H2O 0.15 g/L,MnSO4·H2O 0.104 g/L,pH 7.5;The optimal shaking flask culture conditions were as follows:inoculation amount of 10%,rotation speed of 220 r/min,temperature of 37℃,liquid volume of 80 mL/500 mL,fermentation period of 72 h;Under these conditions,the yield ofγ-polyglutamic acid was up to 32.53 g/L,57.68%higher than that before optimization,which laid a good foundation for the later pilot fermentation.