产O-乙酰高丝氨酸的大肠杆菌构建与发酵测试  

Construction and Fermentation Testing of an O-acetyl-homoserine Producing Escherichia coli Strain

作　　者：杨静[1,2] 李庆刚[3,2] 徐国栋[3,2] 郑小梅[3,2] 郑平 牟海津[1] YANG Jing LI Qing-gang XU Guo-dong ZHENG Xiao-mei ZHENG Ping MOU Hai-jin(School of Food Science and Engineering, Ocean University of China, Qingdao 266003 Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308 Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308)

机构地区：[1]中国海洋大学食品科学与工程科学院,青岛266003 [2]中国科学院天津工业生物技术研究所,天津300308 [3]中国科学院系统微生物工程重点实验室,天津300308

出　　处：《生物技术通报》2017年第9期200-209,共10页Biotechnology Bulletin

基　　金：天津市高层次创新创业团队-微生物细胞工厂设计创新团队;中国科学院重点部署项目(ZDRW-ZS-2016-2)

摘　　要：O-乙酰高丝氨酸(OAH)是具有潜在工业应用价值的前体化合物,可用于制备高丝氨酸与蛋氨酸等。以一株改造自苏氨酸产生菌的Escherichia coli Thr L为出发菌株,过表达OAH合成途径中的关键酶高丝氨酸脱氢酶基因thr A和高丝氨酸乙酰基转移酶基因met X,并利用不同强度的启动子组合优化这两个基因的表达水平,通过发酵培养基中的苏氨酸和酵母粉的浓度优化以提升OAH的产生菌株的生产性能。通过启动子组合优化结果发现,当thr A与met X均采用J23110启动子时,该重组菌株E.coliOAH4的OAH合成能力最强,摇瓶发酵50 h后,其OAH产量为1.54 g/L。当苏氨酸的浓度为2 g/L,酵母粉的浓度为6 g/L时,E.coli OAH4的发酵水平最高,摇瓶发酵50 h后,OAH的产量可进一步提升至1.98 g/L。本研究首次在E.coli中实现了OAH的合成,并通过发酵优化确定了OAH的最优发酵条件,为后续OAH生产应用研究奠定了基础。O-acetyl-homoserine（OAH）is an important industrial ingredient for homoserine and methionine production. We usedthe modified threonine-producing strain Escherichia coli Thr L as the host strain,to overexpress homoserine dehydrogenase gene thr A andhomoserine acetyltransferase gene met X that are key genes for OAH production. The promoter combination was designed to optimize thetranscription of these two key genes. Then,the concentrations of threonine and yeast extract in the fermentation medium were also optimized.After the promoter combination optimization,it showed that the OAH yield of the recombinant strain E.coli OAH4,in which the thr A andmet X genes were separately controlled by J23110 promoter,was the highest and reached up to 1.54 g/L after 50 h incubation. When theconcentrations of threonine and yeast extract were 2 g/L and 6 g/L,respectively,the OAH yield of E. coli OAH4 was the highest and furtherincreased to 1.98 g/L after 50 h incubation. In this study,the synthesis of OAH was achieved in E. coli for the first time. The expression of thr Aand met X,and fermentation conditions of OAH were optimized,which paved the way for the further OAH production research.

关 键 词：大肠杆菌 O-乙酰高丝氨酸 天冬氨酸激酶I/高丝氨酸脱氢酶I 高丝氨酸乙酰基转移酶 发酵培养基优化 

分 类 号：TQ922[轻工技术与工程—发酵工程]