title: High-level exogenous glutamic acid-independent production of poly-(γ-glutamic acid) with organic acid addition in a new isolated Bacillus subtilis C10.
abstract: A new exogenous glutamic acid-independent γ-PGA producing strain was isolated and characterized as Bacillus subtilis C10. The factors influencing the endogenous glutamic acid supply and the biosynthesis of γ-PGA in this strain were investigated. The results indicated that citric acid and oxalic acid showed the significant capability to support the overproduction of γ-PGA. This stimulated increase of γ-PGA biosynthesis by citric acid or oxalic acid was further proved in the 10 L fermentor. To understand the possible mechanism contributing to the improved γ-PGA production, the activities of four key intracellular enzymes were measured, and the possible carbon fluxes were proposed. The result indicated that the enhanced level of pyruvate dehydrogenase (PDH) activity caused by oxalic acid was important for glutamic acid synthesized de novo from glucose. Moreover, isocitrate dehydrogenase (ICDH) and glutamate dehydrogenase (GDH) were the positive regulators of glutamic acid biosynthesis, while 2-oxoglutarate dehydrogenase complex (ODHC) was the negative one.
authors.affiliation: Department of Chemical and Biological Engineering, Institute of Biological Engineering, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Huili
authors.initials: H
authors.lastname: Zhang
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Zhu
authors.forename: Xiangcheng
authors.initials: X
authors.lastname: Zhu
authors.forename: Jin
authors.initials: J
authors.lastname: Cai
authors.forename: Anyi
authors.initials: A
authors.lastname: Zhang
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Hong
authors.forename: Jin
authors.initials: J
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Zhinan
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification*; D019149:Bioreactors / Q000382:microbiology; D053898:Biosynthetic Pathways / Q000187:drug effects; D002264:Carboxylic Acids / Q000494:pharmacology*; D005285:Fermentation / Q000187:drug effects; D018698:Glutamic Acid / Q000378:metabolism*; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D002264:Carboxylic Acids; C511775:poly(gamma-glutamic acid); D000643:Ammonium Chloride; D011099:Polyglutamic Acid; D018698:Glutamic Acid