Systematic pathway engineering of Corynebacterium glutamicum S9114 for l-ornithine production

BACKGROUND: l-Ornithine is a non-protein amino acid with extensive applications in medicine and the food industry. Currently, l-ornithine production is based on microbial fermentation, and few microbes are used for producing l-ornithine owing to unsatisfactory production titer. RESULTS: In this study, Corynebacterium glutamicum S9114, a high glutamate-producing strain, was developed for l-ornithine production by pathway engineering. First, argF was deleted to block l-ornithine to citrulline conversion. To improve l-ornithine production, ncgl1221 encoding glutamate transporter, argR encoding arginine repressor, and putP encoding proline transporter were disrupted. This base strain was further engineered by attenuating oxoglutarate dehydrogenase to increase l-ornithine production. Plasmid-based overexpression of argCJBD operon and lysine/arginine transport protein LysE was tested to strengthen l-ornithine synthesis and transportation. This resulted in efficient l-ornithine production at a titer of 18.4 g/L. CONCLUSION: These results demonstrate the potential of Corynebacterium glutamicum S9114 for efficient l-ornithine production and provide new targets for strain development. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12934-017-0776-8) contains supplementary material, which is available to authorized users.