Improvement of Xylose Utilization and L-ornithine Production by
Metabolic Engineering of Corynebacterium glutamicum
Abstract
L-ornithine is a basic amino acid, which shows significant value in food
and medicine industries. There is a huge space for L-ornithine
production with strains available for metabolic engineering, and it is
urgent to develop a high-efficiency engineering strain for
industrialization. Here, 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 have been
conducted to promote the synthesis of L-ornithine for the first 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 flask fermentation so
far. 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.