title: Biotransformation of glucose to 5-keto-D-gluconic acid by recombinant Gluconobacter oxydans DSM 2343.
abstract: For the conversion of glucose to 5-keto-D-gluconate (5-KGA), a precursor of the industrially important L-(+)-tartaric acid, Gluconobacter strains were genetically engineered. In order to increase 5-KGA formation, a plasmid-encoded copy of the gene encoding the gluconate:NADP-5 oxidoreductase (gno) was overexpressed in G. oxydans strain DSM 2434. This enzyme is involved in the nonphosphorylative ketogenic oxidation of glucose and oxidizes gluconate to 5-KGA. As the 5-KGA reductase activity depends on the cofactor NADP+, the sthA gene (encoding Escherichia coli transhydrogenase) was cloned and overexpressed in the GNO-overproducing G. oxydans strain. Growth of the sthA-carrying strains was indistinguishable from the G. oxydans wild-type strain and therefore they were chosen for the coupled overexpression of sthA and gno. G. oxydans strain DSM 2343/pRS201-gno-sthA overproducing both enzymes showed an enhanced accumulation of 5-KGA.
authors.affiliation: Institut für Biotechnologie 1, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. u.herrmann@fz-juelich.de
authors.forename: U
authors.initials: U
authors.lastname: Herrmann
authors.forename: M
authors.initials: M
authors.lastname: Merfort
authors.forename: M
authors.initials: M
authors.lastname: Jeude
authors.forename: S
authors.initials: S
authors.lastname: Bringer-Meyer
authors.forename: H
authors.initials: H
authors.lastname: Sahm
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001711:Biotransformation; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005942:Gluconates / Q000378:metabolism*; D020600:Gluconobacter oxydans / Q000235:genetics* / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D009250:NADP Transhydrogenases / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005942:Gluconates; D011994:Recombinant Proteins; C008229:2-ketogluconate; D009249:NADP; C093583:5-ketogluconic acid; D010088:Oxidoreductases; C093584:gluconate 5-dehydrogenase; D009250:NADP Transhydrogenases; D005947:Glucose; C030691:gluconic acid