采用补料分批发酵方法对Bacillus subtilis GXA-28摇瓶发酵生产γ-聚谷氨酸的初始葡萄糖和谷氨酸钠浓度、补料时间、补料配方等进行了研究。确定最优补料时间为17 h,补料配方:葡萄糖20 g/L,谷氨酸5 g/L,KH2PO40.5 g/L、MgSO40.1 g/L。在优化的补料条件下,γ-聚谷氨酸产量由16.24 g/L提高至24.36 g/L,较分批发酵提高了50%;生产强度由0.74g/(L·h)提高至0.87 g/(L·h)。研究结果表明,采用分批补料发酵方法能提高γ-聚谷氨酸生产率,实验方法可给γ-聚谷氨酸中试研究提供参考。

In this research,the initial concentration of glucose and sodium glutamate,feeding time,feeding formulation of γ-PGA produced by flask-shaking fermentation of Bacillus subtilis GXA-28 using fed batch culture were investigated.The suitable feeding time was 17 h.Feeding formula was as followes:Glucose 20 g /L,glutamic acid 5 g /L,KH2PO40.5 g /L,MgSO40.1g /L.Under optimal feeding conditions,the production of poly-γ-glutamic acid increased to 24.36 g /L,which was 50% higher than that from batch fermentation.Intensity of production increased from 0.74 g /(L·h) to 0.87 g /(L·h).The results showed that the fed-batch fermentation strategies had a significant effect on the production of γ-poly glutamate and gave a reference for γ-PGA pilot study.