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J Ind Microbiol Biotechnol. 2015 Feb;42(2):297-305. doi: 10.1007/s10295-014-1563-8. Epub 2014 Dec 25.

Deletion of genes involved in glutamate metabolism to improve poly-gamma-glutamic acid production in B. amyloliquefaciens LL3.

Author information

1
Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, People's Republic of China, nk13123@163.com.

Abstract

Here, we attempted to elevate poly-gamma-glutamic acid (γ-PGA) production by modifying genes involved in glutamate metabolism in Bacillus amyloliquefaciens LL3. Products of rocR, rocG and gudB facilitate the conversion from glutamate to 2-oxoglutarate in Bacillus subtillis. The gene odhA is responsible for the synthesis of a component of the 2-oxoglutarate dehydrogenase complex that catalyzes the oxidative decarboxylation of 2-oxoglutarate to succinyl coenzyme A. In-frame deletions of these four genes were performed. In shake flask experiments the gudB/rocG double mutant presented enhanced production of γ-PGA, a 38 % increase compared with wild type. When fermented in a 5-L fermenter with pH control, the γ-PGA yield of the rocR mutant was increased to 5.83 g/L from 4.55 g/L for shake flask experiments. The gudB/rocG double mutant produced 5.68 g/L γ-PGA compared with that of 4.03 g/L for the wild type, a 40 % increase. Those results indicated the possibility of improving γ-PGA production by modifying glutamate metabolism, and identified potential genetic targets to improve γ-PGA production.

PMID:
25540046
DOI:
10.1007/s10295-014-1563-8
[Indexed for MEDLINE]

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