Improvement of Xylose Utilization and L-ornithine Production by Metabolic Engineering of Corynebacterium glutamicum

Abstract

Background: L-ornithine is a basic amino acid, which shows signi cant value in food and medicine industries. Xylose is the most important alternative carbon source of glucose in lignocellulosic hydrolysate. It is urgent to develop a high-e ciency cell factory for L-ornithine production with glucose and xylose. Results: In this study, the genes enconding xylose isomerase and xylulose kinase were introduced into Corynebacterium glutamicum S9114 to establish xylose metabolism pathway, and then xylose became a substitute carbon source of glucose. In addition, the optimization and overexpression of phosphoenolpyruvate carboxylase and pentose transporter had been conducted to promote the synthesis of L-ornithine for the rst time. Furthermore, though optimizing the concentration ratio of glucose and xylose (7:3), adding biotin and thiamine hydrochloride, we arrived at the highest L-ornithine yield 41.5g/L in shaking ask fermentation so far. Conclusions: Our results demonstrate that the combination of metabolic engineering and the optimization of fermentation process can make great potential for L-ornithine production by lignocellulose hydrolysate.