【摘要】 考察了大肠杆菌AS1.505的L谷氨酸脱羧酶对L谷氨酸的专一脱羧作用,分析了转化体系温度、pH值等因素对L谷氨酸脱羧酶活力的影响。实验结果表明最佳工艺为:温度37℃,转化体系pH值4.8,菌体浓度6g/L,吐温800.15g/L,菌龄14h,底物浓度50g/L。L谷氨酸脱羧酶在最适转化条件下比酶活可以达到15036U。1g湿菌体可重复使用3次共转化DL谷氨酸25g,其中L谷氨酸可以完全转化为γ氨基丁酸。D谷氨酸及γ氨基丁酸的总收率可以分别达到理论收率的87%和85%。更多还原

【Abstract】 Dglutamic acid and γaminobutyric acid were produced by means of biotransformation of DLglutamic acid in the presence of LGlutamate decarboxylase in Escherichia coli AS1.505. Factors which affected the enzymatic activity were studied. Under the following conditions: (temperature) 37 ℃, pH 4.8, cell concentration 6 g/L, tween80 0.15 g/L, strain age 14 h, and substrate (concentration) 50 g/L, the specific activity was up to 15 036 U. 25 g of DLglutamic acid could be converted by 1 g of bacteria used for 3 times with conversion rate 100%. The yields of Dglutamic acid and γaminobutyric acid were 87% and 85% respectively.更多还原