title: Bioconversion of l-glutamic acid to α-ketoglutaric acid by an immobilized whole-cell biocatalyst expressing l-amino acid deaminase from Proteus mirabilis.
abstract: The goal of this work was to develop an immobilized whole-cell biocatalytic process for the environment-friendly synthesis of α-ketoglutaric acid (α-KG) from l-glutamic acid. We compared the suitability of Escherichia coli and Bacillus subtilis strains overexpressing Proteus mirabilisl-amino acid deaminase (l-AAD) as potential biocatalysts. Although both recombinant strains were biocatalytically active, the performance of B. subtilis was superior to that of E. coli. With l-glutamic acid as the substrate, α-KG production levels by membranes isolated from B. subtilis and E. coli were 55.3±1.73 and 21.7±0.39μg/mg protein/min, respectively. The maximal conversion ratio of l-glutamic acid to α-KG was 31% (w/w) under the following optimal conditions: 15g/L l-glutamic acid, 20g/L whole-cell biocatalyst, 5mM MgCl2, 40°C, pH 8.0, and 24-h incubation. Immobilization of whole cells with alginate increased the recyclability by an average of 23.33% per cycle. This work established an efficient one-step biotransformation process for the production of α-KG using immobilized whole B. subtilis overexpressing P. mirabilisl-AAD. Compared with traditional multistep chemical synthesis, the biocatalytic process described here has the advantage of reducing environmental pollution and thus has great potential for the large-scale production of α-KG.
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
authors.forename: Gazi Sakir
authors.initials: GS
authors.lastname: Hossain
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Hyun-dong
authors.initials: HD
authors.lastname: Shin
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Chen
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China. Electronic address: gcdu@jiangnan.edu.cn.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China. Electronic address: longliu@jiangnan.edu.cn.
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.affiliation: National Engineering of Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D055162:Biocatalysis; D018914:Cells, Immobilized / Q000378:metabolism; D003605:D-Amino-Acid Oxidase / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D018698:Glutamic Acid / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000378:metabolism*; D011513:Proteus mirabilis / Q000201:enzymology*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D007656:Ketoglutaric Acids; D011994:Recombinant Proteins; D018698:Glutamic Acid; D003605:D-Amino-Acid Oxidase
keywords: Bacillus subtilis; Glutamic acid; Proteus mirabilis; Whole-cell biocatalyst; α-Ketoglutaric acid