Im, Dae-Kyun Hong, Jaeseung Gu, Boncheol Sung, Changmin Oh, Min-Kyu 2024-01-19T17:31:35Z 2024-01-19T17:31:35Z 2021-09-05 2020-06 1860-6768 https://pubs.kist.re.kr/handle/201004/118564 Escherichia coli is engineered for gamma-aminobutyrate (GABA) production in glucose minimal medium. For this, overexpression of mutant glutamate decarboxylase (GadB) and mutant glutamate/GABA antiporter (GadC), as well as deletion of GABA transaminase (GabT), are accomplished. In addition, the carbon flux to the tricarboxylic acid cycle is engineered by the overexpression of gltA, ppc, or both. The overexpression of citrate synthase (CS), encoded by gltA, increases GABA productivity, as expected. Meanwhile, the overexpression of phosphoenolpyruvate carboxylase (PPC) causes a decrease in the rate of glucose uptake, resulting in a decrease in GABA production. The phenotypes of the strains are characterized by C-13 metabolic flux analysis (C-13 MFA). The results reveal that CS overexpression increases glycolysis and anaplerotic reaction rates, as well as the citrate synthesis rate, while PPC overexpression causes little changes in metabolic fluxes, but reduces glucose uptake rate. The engineered strain produces 1.2 g L-1 of GABA from glucose. Thus, by using C-13 MFA, important information is obtained for designing metabolically engineered strains for efficient GABA production. English WILEY-V C H VERLAG GMBH GLUTAMATE-DECARBOXYLASE CORYNEBACTERIUM-GLUTAMICUM CITRATE SYNTHASE ACID GABA COLOCALIZATION SYSTEMS K-12 C-13 Metabolic Flux Analysis of Escherichia coli Engineered for Gamma-Aminobutyrate Production Article 10.1002/biot.201900346 1 BIOTECHNOLOGY JOURNAL, v.15, no.6 BIOTECHNOLOGY JOURNAL 15 6 scie scopus 000530822700001 2-s2.0-85085151065 Biochemical Research Methods Biotechnology & Applied Microbiology Biochemistry & Molecular Biology Biotechnology & Applied Microbiology Article GLUTAMATE-DECARBOXYLASE CORYNEBACTERIUM-GLUTAMICUM CITRATE SYNTHASE ACID GABA COLOCALIZATION SYSTEMS K-12 gamma-aminobutyrate metabolic engineering tricarboxylic acid cycle C-13 metabolic flux analysis