title: Whole-cell conversion of l-glutamic acid into gamma-aminobutyric acid by metabolically engineered Escherichia coli.
abstract: A simple and high efficient way for the synthesis of gamma-aminobutyric acid (GABA) was developed by using engineered Escherichia coli as whole-cell biocatalyst from l-glutamic acid (l-Glu). Codon optimization of Lactococcus lactis GadB showed the best performance on GABA production when middle copy-number plasmid was used as expression vector in E. coli BW25113. The highest production of GABA reached 308.96 g L(-1) with 99.9 mol% conversion within 12 h, when E. coli ΔgabAB (pRB-lgadB) concentrated to an OD600 of 15 in 3 M l-Glu at 45 °C. Furthermore, the strain could be reused at least three cycles in 2 M crude l-Glu with an average productivity of 40.94 g L(-1) h(-1). The total GABA yield reached 614.15 g L(-1) with a molar yield over 99 %, which represented the highest GABA production ever reported. The whole-cell bioconversion system allowed us to achieve a promising cost-effective resource for GABA in industrial application.
authors.affiliation: National Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108 Fujian China.
authors.forename: Chongrong
authors.initials: C
authors.lastname: Ke
authors.affiliation: National Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108 Fujian China.
authors.forename: Xinwei
authors.initials: X
authors.lastname: Yang
authors.affiliation: National Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108 Fujian China.
authors.forename: Huanxin
authors.initials: H
authors.lastname: Rao
authors.affiliation: National Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108 Fujian China.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Zeng
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing, 100101 China.
authors.forename: Meirong
authors.initials: M
authors.lastname: Hu
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing, 100101 China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tao
authors.affiliation: National Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108 Fujian China.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Huang
keywords: Bioconversion; Escherichia coli; Gamma-aminobutyric acid; Glutamate decarboxylase; Whole-cell biocatalyst