Metabolic studies of temperature control strategy on poly(γ-glutamic acid) production in a thermophilic strain Bacillus subtilis GXA-28

Autor: Wang Qinglong, Wei Zeng, Guiguang Chen, Zhiqun Liang, Shuangfeng Zheng, Lin Shu
Rok vydání: 2014
Předmět:
Zdroj: Bioresource Technology. 155:104-110
ISSN: 0960-8524
DOI: 10.1016/j.biortech.2013.12.086
Popis: 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 19.92 g/L at 45 °C with a high productivity of 0.91 g/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.
Databáze: OpenAIRE