Genomics and transcriptomics-guided metabolic engineering Corynebacterium glutamicum for L-arginine production

L-arginine is a semi-essential amino acid that is broadly used as food additives and pharmaceutical intermediates. The synthesis of L-arginine is restricted by complex metabolic mechanisms and suboptimal fermentation con-ditions. Initially, a mutant strain that accumulated 19.4 g/L L-arginine was generated by random mutagenesis. Subsequently, a mutation of the repressor protein (argRG159D) in the L-arginine operon and glutamate synthase (gltD) with 532-fold upregulation were identified to be vital for L-arginine production by multi-omic analysis. Systematic metabolic engineering was used to modify the strain, which included interfering with alpha-ketoglutarate dehydrogenase complex (ODHC) activity by knocking out serine/threonine-protein kinase (pknG), enhancing the expression of multiple key enzymes in the L-arginine synthesis pathway, and increasing the availability of intracellular cofactor (NADPH) and energy (ATP). Finally, C. glutamicum ARG12 produced 71.3 g/L L-arginine, with a yield of 0.43 g/g glucose by fermentation optimization. This study provides new ideas to boost L-arginine production.

Automated summary

L-arginine is an important amino acid used in food and pharmaceutical industries. This study investigated the metabolic mechanisms and fermentation conditions affecting L-arginine production. By generating mutant strains and conducting multi-omic analysis, vital mutations in the L-arginine operon and glutamate synthase were identified. The study also applied systematic metabolic engineering to enhance L-arginine production by modifying key enzymes and increasing cofactor availability. Through fermentation optimization, the engineered strain produced a high yield of L-arginine. This study provides new insights into boosting L-arginine production.