title: Heterologous expression of the human Phosphoenol Pyruvate Carboxykinase (hPEPCK-M) improves hydrogen and ethanol synthesis in the Escherichia coli dcuD mutant when grown in a glycerol-based medium.
abstract: The production of biodiesel has emerged as an alternative to fossil fuels. However, this industry generates glycerol as a by-product in such large quantities that it has become an environmental problem. The biotransformation of this excess glycerol into other renewable bio-energy sources, like H2and ethanol, by microorganisms such as Escherichia coli is an interesting possibility that warrants investigation. In this work we hypothesized that the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP) could be improved by a controlled expression of the human mitochondrial GTP-dependent PEP carboxykinase. This heterologous expression was tested in several E. coli mutant backgrounds with increased availability of C4 intermediates. It was found that this metabolic rewiring improved the synthesis of the target products in several mutants, with the dcuD mutant being the most suitable background for hydrogen and ethanol specific productions and glycerol consumption. These factors increased by 2.46, 1.73 and 1.95 times, respectively, when compared to those obtained for the wild-type strain.
authors: Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus de Excelencia Internacional Agroalimentario (ceiA3), University of Cádiz, Avda. República Saharui s/n, 11510 Puerto Real, Cádiz, Spain. Electronic address: antonio.valle@uca.es.
authors: Antonio
authors: A
authors: Valle
authors: Department of Chemical Engineering and Food Technology, Campus de Excelencia Internacional Agroalimentario (ceiA3), University of Cádiz, Avda. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain.
authors: Gema
authors: G
authors: Cabrera
authors: Department of Chemical Engineering and Food Technology, Campus de Excelencia Internacional Agroalimentario (ceiA3), University of Cádiz, Avda. República Saharaui s/n, 11510 Puerto Real, Cádiz, Spain.
authors: Domingo
authors: D
authors: Cantero
authors: Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus de Excelencia Internacional Agroalimentario (ceiA3), University of Cádiz, Avda. República Saharui s/n, 11510 Puerto Real, Cádiz, Spain. Electronic address: jorge.bolivar@uca.es.
authors: Jorge
authors: J
authors: Bolivar
mesh_terms: D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005798:Genes, Bacterial; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D060847:Metabolic Engineering; D009154:Mutation; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D056804:Biofuels; D003470:Culture Media; D011994:Recombinant Proteins; D000431:Ethanol; D006859:Hydrogen; C000597251:PCK2 protein, human; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D005990:Glycerol
keywords: Ethanol; Glycerol fermentation; Hydrogen; hPEPCK-M