Enhanced l-ornithine production from glucose and sucrose via manipulation of the fructose metabolic pathway in Corynebacterium glutamicum

Abstract

l-Ornithine, an important non-essential amino acid, has considerable medicinal value in the treatment of complex liver diseases. Microbial fermentation strategies using robust engineered strains have remarkable potential for producing l-ornithine. We showed that glucose and sucrose co-utilization accumulate more l-ornithine in Corynebacterium glutamicum than glucose alone. Further manipulating the expression of intracellular fructose-1-phosphate kinase through the deletion of pfkB1resulted in the engineered strain C. glutamicum SO30 that produced 47.6 g/L of l-ornithine, which represents a 32.8% increase than the original strain C. glutamicum SO26 using glucose as substrate (35.88 g/L). Moreover, fed-batch cultivation of C. glutamicum SO30 in 5-L fermenters produced 78.0 g/L of l-ornithine, which was a 78.9% increase in yield compared with that produced by C. glutamicum SO26. These results showed that manipulating the fructose metabolic pathway increases l-ornithine accumulation and provides a reference for developing C. glutamicum to produce valuable metabolites. Graphical Abstract: [Figure not available: see fulltext.]