Development of L-Arginine Producing Microbial Cell Factory through Metabolic Engineering Based on Corynebacterium glutamicum

Abstract

Microbial cell factory for production of L-arginine was developed based onCorynebacterium glutamicum. Random mutagenesis was performed on C. glutamicumto increase tolerance against L-arginine. Arginine operon repressor proteins wereinactivated. The PPP flux was strengthened to increase the pool of NADPH bydownregulating the pgi gene and overexpressing the opcA, pgl, tal, tkt, and zwfgenes. Next, the Ncgl1221 gene encoding L-glutamate exporter was inactivatedto channel L-glutamate to L-arginine formation. Also, the expression levels ofthe argF and carAB genes were optimized for converting L-ornithine to L-citrullineeffectively. Finally, the argGH operon was overexpressed. Fed-batch fermentationof the final strain was performed in a 1,500 L bioreactor resulting 81 g/L ofL-arginine production. The approaches described here will be useful in developingstrains of Corynebacteria regarding the production of arginine and its derivatives.[This work was supported by the Technology Development Program to Solve ClimateChanges on Systems Metabolic Engineering for Biorefineries from the Ministryof Science, ICT and Future Planning (MSIP) through the National Research Foundation(NRF) of Korea.]