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

Abstract

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.ResultsIn 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.ConclusionThese results demonstrate the potential of Corynebacterium glutamicum S9114 for efficient l-ornithine production and provide new targets for strain development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-017-0776-8) contains supplementary material, which is available to authorized users.

Development of a System of High Ornithine and Citrulline Production by a Plant-Derived Lactic Acid Bacterium, <i>Weissella confusa</i> K-28

“…The limited strains, which are C. glutamicum mutants modified genetically, have been proven to produce ornithine with satisfactory efficacy. 28) In contrast to the mutant strains, the productivity of the wild-type C. glutamicum produce only 0.5 g/L ornithine. 28,29) To produce ornithine, in general, arginine is decomposed by arginase urease or arginine deiminase.…”

“…28) In contrast to the mutant strains, the productivity of the wild-type C. glutamicum produce only 0.5 g/L ornithine. 28,29) To produce ornithine, in general, arginine is decomposed by arginase urease or arginine deiminase. 30) The present study shows that W. confusa K-28, harboring the ADI pathway, has significant potential to produce ornithine at a high level.…”

“…The PucR is a transcriptional activator involved in the catabolism of purine and its intermediates, such as uric acid, allantoin, or allantoic acid, and activates the purine degradation pathway. 26,27) We evaluated the expression of each gene in the ADI gene cluster during the fed-batch culture using a jar fermenter and the RT-PCR method (Fig. 5).…”

Proteome analysis guided genetic engineering of Corynebacterium glutamicum S9114 for tween 40-triggered improvement in l-ornithine production

“…In a previous study, we systematically developed an engineered strain of C. glutamicum S9114 through the deletion of argF, ncgl1221, argR, and putP, the attenuation of odhA, and the overexpression of argCJBD, which produced up to 19 g/L of l-ornithine in a shaker flask culture [15,16]. In the present study, the effects of tween 40 on l-ornithine production were investigated.…”

“…Currently, several studies have attempted to develop metabolically engineered strains that are able to rapidly convert a certain amount of glucose, or other alternative carbon resource, into l-ornithine. The biosynthesis pathway of l-ornithine in C. glutamicum is described in previous studies [15][16][17][18]. Jensen et al [19] developed an l-ornithine producing C. glutamicum strain ORN6 through rational engineering, including the deletion of argF, argR, and argG, enhancing the supplement of glutamate via the optimized expression of gdh, redirection of the metabolic flux to the pentose phosphate pathway to provide adequate cofactor NADPH via a change of the start codon of pgi, overexpression of a feedback insensitive N-acetylglutamate kinase, and the insertion of a second copy of the argCJB M D operon into the chromosome, resulting in the production of l-ornithine with a yield of 0.52 g of l-ornithine per g glucose.…”