Implication of ornithine acetyltransferase activity on l‐ornithine production in Corynebacterium glutamicum

Abstract l ‐Ornithine is an intermediate of the l ‐arginine biosynthetic pathway in Corynebacterium glutamicum . The effect of ornithine acetyltransferase (OATase; ArgJ) on l ‐ornithine production was investigated, and C. glutamicum 1006 was engineered to overproduce l ‐ornithine as a major product by inactivating regulatory repressor argR gene and overexpressing argJ gene. A genome sequence analysis indicated that the argF gene encoding ornithine carbamoyltransferase in C. glutamicum 1006 was mutated, resulting in the accumulation of a certain amount of l ‐ornithine (20.5 g/L). The assays using a crude extract of C. glutamicum 1006 indicated that the l ‐ornithine concentration for 50% inhibition of OAT was 5 mM. To enhance l ‐ornithine production, the argJ gene from C. glutamicum ATCC 13032 was overexpressed. In flask cultures, the resulting strain, C. glutamicum 1006∆ argR‐argJ , produced 31.6 g/L l ‐ornithine, which is 54.15% more than that produced by C. glutamicum 1006. The OAT activity of C. glutamicum 1006∆ argR ‐ argJ was significantly greater than that of C. glutamicum 1006, and this study achieved the highest conversion ratio of sugar to acid (0.396 g/g) compared with those of previous reports. ArgJ strongly influences the production of l ‐ornithine in C. glutamicum .