Improvedl-ornithine production inCorynebacterium crenatumby introducing an artificial linear transacetylation pathway

• DOI: 10.1007/s10295-018-2037-1
• Publication Date: 2018-05-04T13:25:50Z
• Authors: Qunfeng Shu; Meijuan Xu; Jing Li; Taowei Yang; Xian Zhang; Zhenghong Xu; Zhiming Rao
• Keywords: Ornithine decarboxylase antizyme

Abstractl-Ornithine is a non-protein amino acid with extensive applications in the food and pharmaceutical industries. In this study, we performed metabolic pathway engineering of an l-arginine hyper-producing strain of Corynebacterium crenatum for L-ornithine production. First, we amplified the L-ornithine biosynthetic pathway flux by blocking the competing branch of the pathway. To enhance L-ornithine synthesis, we performed site-directed mutagenesis of the ornithine-binding sites to solve the problem of l-ornithine feedback inhibition for ornithine acetyltransferase. Alternatively, the genes argA from Escherichia coli and argE from Serratia marcescens, encoding the enzymes N-acetyl glutamate synthase and N-acetyl-l-ornithine deacetylase, respectively, were introduced into Corynebacterium crenatum to mimic the linear pathway of L-ornithine biosynthesis. Fermentation of the resulting strain in a 5-L bioreactor allowed a dramatically increased production of L-ornithine, 40.4 g/L, with an overall productivity of 0.673 g/L/h over 60 h. This demonstrates that an increased level of transacetylation is beneficial for L-ornithine biosynthesis.