学术
摘 要:
实现了戊二酰基-7-氨基头孢烷酸（GL-7ACA）酰化酶的组成型表达，并通过替换重组质粒启动子的RBS序列，在摇瓶培养条件下，使新构建的重组质粒pGEMKT—HPRfACY在大肠杆菌JM105中表达GL-7ACA酰化酶酶活达到0．44U／mL，是替换前的2倍．使用廉价的玉米浆作为培养基中氮源主要来源，使JM105／pGEMKT—HPRfACY菌株酶活提高到2．98U／mL．采用补料批式培养，利用流加营养物控制发酵中后期的pH值，在pH为7．5的条件下，酶活峰值达到6．37U／mL．该体系无需诱导，工艺操作过程简单，成本低廉．[著者文摘]
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文章出处:
《过程工程学报》-2008年8卷1期 -140-143页
栏目信息:
分 类 号:
文献标识码:
A
文章编号:
1009-606X（2008）01-0140-04
Over-expression of GL-7-ACAAcylase Gene in E. coli
LIN Chen-lu, LI Qiang, LIU Ya-fei, WANG Bo （Department of Chemical Engineering, Tsinghua University, Beijing 100084, China）
Abstract:
The constitutive expression of glutaryl-7-amidocephalosporanic acid （GL-7-ACA） acylase was realized. Based on it, a new plasmid pGEMKT-HPfACY with optimized RBS was constructed and transformed into E. coli JM 105. After culturing in LB media, this recombinant strain reached an activity of 0.44 U/mL. This activity was twice of former one while the activity of the strain JM 105/pGEMKT-HPRfACY reached as high as 2.98 U/mL using corn-steep as culture media. The acylase activity of recombinant strain hit 6.37 U/mL, using a strategy of controlling pH 7.5 byadding nutrient such as glycerin.[著者文摘]
Key words:
7-aminocephalosporanic acid; glutaryl-7-amidocephalosporanic acid acylase; constitutive expression
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