Genetic manipulation of a primary metabolic pathway for L-ornithine production in Escherichia coli.
Metabolic engineering has been used to improve L-ornithine biosynthesis in Escherichia coli W3110. L-Ornithine production increased from 0.3 to 3.2 mg/g (dry cell weight) when the primary L-ornithine biosynthetic pathway was optimized by disrupting the pathway transcription repressor, thereby increasing the expression of the genes involved in the pathway, and by preventing conversion of L-ornithine into citrulline. When a feedback-resistant N-acetylglutamate synthetase gene (argA214) was placed under the control of the arabinose-inducible promoter, either in the chromosome or on a multicopy plasmid in the cell, the combination of overexpression of argA214 with an argF argI argR triple knockout mutation had an additive effect on L-ornithine production but only when exogenous glutamate was present. When speF (which encodes ornithine decarboxylase) and proB (which encodes gamma-glutamyl kinase) were inactivated to prevent the conversion of L-ornithine to putrescine and to block the biosynthesis of a side branch of L-ornithine, respectively, L-ornithine production was further enhanced approx. 140% from 5.5 to 13.2 mg/g (dry cell weight).
Lee
Young-Joon
YJ
Division of Animal Science and Biotechnology, Sangji University, 660 Woosan-dong, Wonju-si, Gangwon-do, 220-702, Korea.
Cho
Jae-Yong
JY
D051046:Amino-Acid N-Acetyltransferase / Q000235:genetics; D001089:Arabinose / Q000378:metabolism; D001709:Biotechnology / Q000379:methods*; D002956:Citrulline / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005818:Genetic Engineering; D005821:Genetic Techniques; D008954:Models, Biological; D008957:Models, Genetic; D009952:Ornithine / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011700:Putrescine / Q000737:chemistry
D002956:Citrulline; D001089:Arabinose; D009952:Ornithine; D051046:Amino-Acid N-Acetyltransferase; D011700:Putrescine