Enhanced production of poly-3-hydroxybutyrate by recombinant Escherichia coli containing NAD kinase and phb CAB operon  

作　　者：Shaoqin Zhang Lei Fang Zhengjun Li Yingying Guo Guo-Qiang Chen 

机构地区：[1]Center for Synthetic and Systems Biology, School of Life Science, Tsinghua-Peking Center for Life Sciences,Tsinghua University [2]Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology [3]Center for Nano and Micro Mechanics, Tsinghua University

出　　处：《Science China Chemistry》2016年第11期1390-1396,共7页中国科学（化学英文版）

基　　金：supported by the National Basic Research Program of China (2012CB725201);the National Natural Science Foundation of China (31430003, 31270146)

摘　　要：With the help of Tn5 transposon technique, gene yfj B encoding NAD kinase in Escherichia coli(E. coli) was inserted into chromosome of recombinant E. coli polyhydroxybutyrate(PHB) containing PHB synthesis operon integrated in the host genome. After successful transposition of an extra yfj B gene copy into genome, the selected recombinant named E. coli PHBTY4 showed stronger NAD kinase activity than that of E. coli PHB. Shake flask studies suggested that both cell dry weight and PHB accumulation were significantly increased in E. coli PHBTY4 compared with that of the control. E. coli PHBTY4 produced approximately 23 g/L PHB compared with its control which synthesized only 10 g/L PHB when grown under the same conditions in a 6 L fermentor after 32 h of cultivation. In addition, E. coli PHBTY4 maintained high genetic stability during the cultivation processes. These results revealed a practical method to construct genetically stable strains harboring extra NAD kinase gene to enhance NADP(H)-dependent bio-reactions.With the help of Tn5 transposon technique, gene yfj B encoding NAD kinase in Escherichia coli（E. coli） was inserted into chromosome of recombinant E. coli polyhydroxybutyrate（PHB） containing PHB synthesis operon integrated in the host genome. After successful transposition of an extra yfj B gene copy into genome, the selected recombinant named E. coli PHBTY4 showed stronger NAD kinase activity than that of E. coli PHB. Shake flask studies suggested that both cell dry weight and PHB accumulation were significantly increased in E. coli PHBTY4 compared with that of the control. E. coli PHBTY4 produced approximately 23 g/L PHB compared with its control which synthesized only 10 g/L PHB when grown under the same conditions in a 6 L fermentor after 32 h of cultivation. In addition, E. coli PHBTY4 maintained high genetic stability during the cultivation processes. These results revealed a practical method to construct genetically stable strains harboring extra NAD kinase gene to enhance NADP（H）-dependent bio-reactions.

关 键 词：PHB polyhydroxyalkanoates Tn5 transposon NAD kinase Escherichia coli 

分 类 号：TQ920.6[轻工技术与工程—发酵工程] TQ317