title: Rational design of Escherichia coli for L-isoleucine production.
abstract: Metabolic engineering of Escherichia coli was performed to construct a 100% rationally engineered strain capable of overproducing L-isoleucine, an important branched-chain amino acid. The thrABC (encoding L-threonine biosynthetic enzymes), ilvA (encoding feedback-resistant threonine dehydratase), ilvIH (encoding feedback-resistant acetohydroxy acid synthase III), and ygaZH (encoding branched-chain amino acid exporter) genes were amplified by plasmid-based overexpression. The ilvCED (encoding L-isoleucine biosynthetic enzymes) and lrp (encoding global regulator Lrp) genes were also amplified by chromosomal promoter replacement in order to further increase the flux toward L-isoleucine. The final engineered E. coli strain was able to produce 9.46 g/L of L-isoleucine with a yield of 0.14 g/g of glucose by fed-batch culture. The overall design principles described here for the production of highly regulated product should be useful in designing strains for the production of other similar bioproducts.
authors: Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
authors: Jin Hwan
authors: JH
authors: Park
authors: Jae Eun
authors: JE
authors: Oh
authors: Kwang Ho
authors: KH
authors: Lee
authors: Ji Young
authors: JY
authors: Kim
authors: Sang Yup
authors: SY
authors: Lee
mesh_terms: D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism; D000597:Amino Acids, Branched-Chain / Q000235:genetics / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000379:methods; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D005809:Genes, Regulator; D005818:Genetic Engineering / Q000379:methods; D007532:Isoleucine / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods; D013912:Threonine / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D013913:Threonine Dehydratase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism
chemical_list: D000597:Amino Acids, Branched-Chain; D007532:Isoleucine; D013912:Threonine; D000095:Acetolactate Synthase; D013913:Threonine Dehydratase