Improve gamma-aminobutyric acid production in Corynebacterium glutamicum by optimizing the metabolic flux

Gamma-aminobutyric acid is an important nonprotein amino and has been extensively applied in pharmaceuticals, livestock, food additives, so on. It to develop Corynebacterium glutamicum strains that can efficiently produce gamma-aminobutyric from glucose. In this study, production of C. CGY700 was improved by construction CO2 anaplerotic reaction overexpression citrate synthase. The co-expression ppc encoding phosphoenolpyruvate carboxylase gltA synthase constructed optimized the chromosome compensate carbon loss conquer metabolic bottleneck. expression were controlled promoters Ptac PtacM, optimal mode PtacM-ppc-Ptac-gltA determined. Simultaneously, genes pknG serine/threonine protein kinase G ldh l-lactate dehydrogenase deleted, glnA2 glutamine overexpressed chromosome. final strain CGY-PG-304 study could 41.17 g/L shake flask cultivation 58.33 via Fed-Batch fermentation with a yield 0.30 g/g genome editing; therefore, it stable not necessary add any antibiotics inducer during fermentation.