title: Gluconobacter oxydans NAD-dependent, D-fructose reducing, polyol dehydrogenases activity: screening, medium optimisation and application for enzymatic polyol production.
abstract: Gluconobacter oxydans LMG 1489 was selected as the best strain for NAD(P)-dependent polyol dehydrogenase production. The highest enzyme activities were obtained when this strain was cultivated on a medium consisting of 30 g glycerol l(-1), 7.2 g peptone l(-1) and 1.8 g yeast extract l(-1). Two D-fructose reducing, NAD-dependent intracellular enzymes were present in the G. oxydans cell-free extract: sorbitol dehydrogenase, and mannitol dehydrogenase. Substrate reduction occurred optimally at a low pH (pH 6), while the optimum for substrate oxidation was situated at alkaline pHs (pH 9.5-10.5). The mannitol dehydrogenase was more thermostable than the sorbitol dehydrogenase. The cell-free extract could be used to produce D-mannitol and D-sorbitol enzymatically from D-fructose. Efficient coenzyme regeneration was accomplished by formate dehydrogenase-mediated oxidation of formate into CO2.
authors.affiliation: Department of Biochemical and Microbial technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Parmentier
authors.forename: Joeri
authors.initials: J
authors.lastname: Beauprez
authors.forename: Filip
authors.initials: F
authors.lastname: Arnaut
authors.forename: Wim
authors.initials: W
authors.lastname: Soetaert
authors.forename: Erick J
authors.initials: EJ
authors.lastname: Vandamme
mesh_terms: D001709:Biotechnology; D002244:Carbon; D002245:Carbon Dioxide / Q000737:chemistry; D002474:Cell-Free System; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D005285:Fermentation; D005632:Fructose / Q000737:chemistry / Q000494:pharmacology; D020600:Gluconobacter oxydans / Q000201:enzymology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007064:L-Iditol 2-Dehydrogenase / Q000378:metabolism*; D008353:Mannitol / Q000737:chemistry; D009243:NAD / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D013012:Sorbitol / Q000737:chemistry / Q000494:pharmacology; D013045:Species Specificity; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
chemical_list: D003470:Culture Media; D007477:Ions; D009243:NAD; D002245:Carbon Dioxide; D005632:Fructose; D008353:Mannitol; D013012:Sorbitol; D002244:Carbon; D004492:Edetic Acid; D007064:L-Iditol 2-Dehydrogenase; D010100:Oxygen