中文摘要：

以短乳杆菌BS2为研究对象,根据已优化的培养条件,使用15L发酵罐进行分批及分批补料发酵实验,在严格控制条件下观察γ-氨基丁酸（GABA）的生物转化过程,克服摇瓶发酵的不足。采用初始pH值为5,发酵期间不控制pH值的条件下进行分批发酵;而后通过发酵期间控制pH值为5的条件下再次进行分批发酵,GABA含量得到有效提高,而谷氨酸钠和葡萄糖分别在32h和44h基本耗尽;然后采用初始pH值为5,发酵期间控制pH值不变的条件下分别在32h补入谷氨酸钠,44h补入葡萄糖,其中,补加550g/L葡萄糖200mL,630g/L谷氨酸钠200mL。补料发酵时,两者流加速度均为11.1mL/min,流加18min。流加结束后培养基中葡萄糖和谷氨酸钠含量达到18g/L以上,基本达到在初始发酵时的质量浓度,而谷氨酸钠在56h基本耗尽,GABA产量达到22.5g/L,最后在56h第2次补加谷氨酸钠,操作同上,GABA产量在104h达到33g/L以上。

英文摘要：

In this study,Lactobacillus brevis BS2,a high yield gamma-aminobutyric acid（γ-GABA）-producing strain capable of enriching Zn,was used to conduct batch and fed-batch fermentation in a 15-L fermenter for exploring the biotransformation of γ-GABA.An initial pH of 5 was used for batch fermentation with and without holding pH at 5.As a result of holding pH,the production ofγ-GABA was considerably increased and sodium glutamate and glucose were almost all consumed at the time points of 32 h and 44 h,respectively.When the initial pH of 5 was held during the fermentation,adding 200 mL of 630 g/L sodium glutamate and 200 mL of 550 g/L glucose（18 min needed at the same flow rate of 11.1 mL/min） was necessary at the time points of 32 h and 44 h,respectively.As a result,the glucose and sodium glutamate in the medium were both over 18 g/L at the end of their additions,which basically reached their initial levels before the fermentation.At 56 h,almost all glutamate was depleted and the production of γ-GABA reached 22.5 g/L.Finally,the second addition of sodium glutamate was done as described above at 56 h.The production of γ-GABA was over 33 g/L at 104 h.