用大肠杆菌AS1.505进行液态发酵生产谷氨酸脱羧酶并优化培养基,考察了碳源、氮源、复合营养物质、起始pH及发酵时间对酶活的影响,确定最佳产酶培养基组成为:葡萄糖1.0g/dL,蛋白胨3.0g/dL,氯化钠0.3g/dL,磷酸氢二钾0.1g/dL,硫酸镁0.02g/dL,17谷氨酸0.01g/dL,玉米浆1.5g/dL,生物素30ug/L,麸皮4g/dL;pH6.5。在此基础上,设计发酵条件的优化实验。实验结果表明为:250mL的三角瓶装液量25mL,37℃,起始pH6.5,培养18h达到产酶高峰,产酶活力可达1290U/mL。
Compositions of culture medium and fermentation conditions were studied to improve quantity of Glutamic acid decarboxylase (GAD) production by AS 1. 505 liquid fermentation. The optimized medium and conditions were as follows ; glucose 1.0%, tryptone 3.0%, NaCl 0.3 %, K2HPO4 3H2O 0. 1G, MgSO4 7H2O 0.02%, L-Glutamic acid 0. 01G, corn steep liquor 1.5%, biotin 20 ug/L, bran 4%, initial pH 6.5, 37℃, liquid volume 25 mL/250 mL baffled flask, 200 r/min, for 18 hours. Under these conditions, the activity of GAD was achieved at 1 290 U/mL.