High-level production of Arthrobacter aurescens CYC705 nitrilase in Escherichia coli for biosynthesis of iminodiacetic acid

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• 作者：Erzheng Su ; Chao Lu ; Xiaoqiang Ma ; Wenwen Cai and Shujing Zhu
• 刊名：Biotechnology and Applied Biochemistry
• 出版年：2016
• 出版时间：July/August 2016
• 年：2016
• 卷：63
• 期：4
• 页码：564-571
• 全文大小：786K
• ISSN：1470-8744

文摘

Nitrilase from Arthrobacter aurescens CYC705 can hydrolyze the iminodiacetonitrile to iminodiacetic acid (IDA) efficiently, and its high-level production in Escherichia coli has not been established. In the present work, the production of this nitrilase expressed in E. coli BL21(DE3) with a recombinant plasmid pET28a-cyc705 was optimized. Various culture conditions and process parameters including medium components and concentrations, inducer types and concentrations, inducing temperature and time were systematically examined in a shake flask. After optimization, the OD₆₀₀, nitrilase activity, and productivity were obviously improved and achieved to 40.91 ± 1.341, 98.12 ± 1.248 U/mL, and 2,230 ± 28.36 U L⁻¹ H⁻¹, respectively, about 2.1-, 30-, and 33-fold increases as compared with those in the primary medium. Furthermore, four different fermentation strategies were adopted to scale up cultivation of the recombinant E. coli BL21(DE3)/pET28a-cyc705 in a 3.7-L fermenter. Substituting the peanut powder with fish peptone and accompanying with 1.0% glycerol feeding could significantly reduce the bubble production and shorten the fermentation time, which resulted in a nitrilase productivity of 4,653 ± 38.16 U L⁻¹ H⁻¹ that was about two times higher than that in a shake flask. The high-level production of A. aurescens CYC705 nitrilase established in this study will meet the need of industrial biosynthesis of IDA.