title: Combining rational metabolic engineering and flux optimization strategies for efficient production of fumaric acid.
abstract: Fumaric acid is an important C4-dicarboxylic acid widely used in chemical, food, and pharmaceutical industries. Rational metabolic engineering together with flux optimization were performed for the development of an Escherichia coli strain capable of efficiently producing fumaric acid. The initial engineered strain, CWF4N overexpressing phosphoenolpyruvate carboxylase (PPC), produced 5.30 g/L of fumaric acid. Optimization of PPC flux by examining 24 types of synthetic PPC expression vectors further increased the titer up to 5.72 g/L with a yield of 0.432 g/g·glucose. Overexpression of the succinate dehydrogenase complex (sdhCDAB) led to an increase in carbon yield up to 0.493 g/g·glucose. Based on this mutant strain, citrate synthase (CS) was combinatorially overexpressed and balanced with PPC using 48 types of synthetic expression vectors. As a result, 6.24 g/L of fumaric acid was produced with a yield of 0.500 g/g·glucose. Fed-batch culture of this final strain allowed production of 25.5 g/L of fumaric acid with a yield of 0.366 g/g·glucose. Deletion of the aspA gene encoding aspartase and supplementation of aspartic acid further increased the fumaric acid titer to 35.1 g/L with a yield of 0.490 g/g·glucose.
authors.affiliation: Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 plus 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.forename: Chan Woo
authors.initials: CW
authors.lastname: Song
authors.affiliation: Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 plus 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. leesy@kaist.ac.kr.|BioProcess Engineering Research Center, KAIST, Daejeon, 305-701, Republic of Korea. leesy@kaist.ac.kr.|BioInformatics Research Center, KAIST, Daejeon, 305-701, Republic of Korea. leesy@kaist.ac.kr.
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005650:Fumarates / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D005822:Genetic Vectors; D005947:Glucose / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000235:genetics*
chemical_list: D005650:Fumarates; C032005:fumaric acid; D005947:Glucose
keywords: Escherichia coli; Flux optimization; Fumaric acid; Metabolic engineering