Metabolic engineering of Corynebacterium glutamicum S9114 to enhance the production of l-ornithine driven by glucose and xylose

Abstract

l-ornithine, an important amino acid, is widely used in food and medicine industries. l-ornithine production mainly relies on microbial fermentation, which may not meet the industrial requirement owing to the poor fermentation ability of available strains. Herein, mscCG2 deletion, CgS9114_12202 (gdh2) overexpression and rational modulation in tricarboxylic acid cycle was firstly demonstrated to increase l-ornithine production in engineered Corynebacterium glutamicum S9114. By further modulate glucose utility result in strain SO26 that produced 38.5 g/L or 43.6 g/L of l-ornithine in shake flask and fed-batch fermentation, respectively. This was 25% higher than that of the original strain (30.8 g/L) and exhibits highest titer reported in shake-flask. Moreover, the incorporation of xylose pathway in the engineered strain resulted in the highest l-ornithine production titer (18.9 g/L) and yield (0.40 g/g xylose) with xylose substrate. These results illustrate the tremendous potential of the engineered strain C. glutamicum S9114 in l-ornithine production.

Keywords: Corynebacterium glutamicum; Glucose; Metabolic engineering; Xylose; l-ornithine.