title: Production of succinate by a pflB ldhA double mutant of Escherichia coli overexpressing malate dehydrogenase.
abstract: The gene encoding malate dehydrogenase (MDH) was overexpressed in a pflB ldhA double mutant of Escherichia coli, NZN111, for succinic acid production. With MDH overexpression, NZN111/pTrc99A-mdh restored the ability to metabolize glucose anaerobically and 0.55 g/L of succinic acid was produced from 3 g/L of glucose in shake flask culture. When supplied with 10 g/L of sodium bicarbonate (NaHCO(3)), the succinic acid yield of NZN111/pTrc99A-mdh reached 1.14 mol/mol glucose. Supply of NaHCO(3) also improved succinic acid production by the control strain, NZN111/pTrc99A. Measurement of key enzymes activities revealed that phosphoenolpyruvate (PEP) carboxykinase and PEP carboxylase in addition to MDH played important roles. Two-stage culture of NZN111/pTrc99A-mdh was carried out in a 5-L bioreactor and 12.2 g/L of succinic acid were produced from 15.6 g/L of glucose. Fed-batch culture was also performed, and the succinic acid concentration reached 31.9 g/L with a yield of 1.19 mol/mol glucose.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 200237 Shanghai, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Li
authors.forename: Jingli
authors.initials: J
authors.lastname: Xie
authors.forename: Qin
authors.initials: Q
authors.lastname: Ye
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001698:Biomedical Engineering; D019149:Bioreactors / Q000382:microbiology; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D005798:Genes, Bacterial; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000235:genetics / Q000378:metabolism; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D011994:Recombinant Proteins; D019802:Succinic Acid; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase; D000123:Acetyltransferases; C022560:formate C-acetyltransferase; D010730:Phosphoenolpyruvate Carboxylase; D019764:Phosphoenolpyruvate Carboxykinase (ATP)