title: Metabolic studies of temperature control strategy on poly(γ-glutamic acid) production in a thermophilic strain Bacillus subtilis GXA-28.
abstract: A thermophilic strain Bacillus subtilis GXA-28 with capability of γ-PGA production was characterized, and its product was identified. The effect of temperatures on cell growth, γ-PGA yield and molecular weight were investigated. Results showed that γ-PGA yield reached 19.92g/L at 45°C with a high productivity of 0.91g/L/h, and the molecular weight reached 3.03×10(6)Da. Then, the flux distribution and the key enzyme activities at 2-oxoglutarate branch under specified temperature were determined to illustrate the possible metabolic mechanism contributing to the improved γ-PGA production. Results indicated that the fluxes from iso-citrate to 2-oxoglutarate and from 2-oxoglutarate to glutamate were increased with high activity of isocitrate dehydrogenase and glutamate dehydrogenase, which led to enhance γ-PGA production. This work firstly employed temperature control strategy to improve γ-PGA production, and provided novel information on the metabolic mechanism of γ-PGA biosynthesis in Bacillus species.
authors.affiliation: Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning 530004, Guangxi, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, Guangxi, China; College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zeng
authors.affiliation: College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
authors.forename: Guiguang
authors.initials: G
authors.lastname: Chen
authors.affiliation: College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning 530004, Guangxi, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, Guangxi, China; College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
authors.forename: Shuangfeng
authors.initials: S
authors.lastname: Zheng
authors.affiliation: College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Shu
authors.affiliation: Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning 530004, Guangxi, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, Guangxi, China; College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China. Electronic address: zqliang@gxu.edu.cn.
authors.forename: Zhiqun
authors.initials: Z
authors.lastname: Liang
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000502:physiology*; D008954:Models, Biological; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis; D013045:Species Specificity; D013696:Temperature
chemical_list: C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D018698:Glutamic Acid; D005947:Glucose
keywords: Bacillus sutilis; Enzyme activity; Metabolic flux; Poly(γ-glutamic acid); Temperature