title: Effect of magnesium ions on fermentative and respirative functions in Pichia stipitis under oxygen-restricted growth.
abstract: Mg2+ level affected growth, xylitol and ethanol production by P. stipitis grown under microaerophilic conditions. Low Mg2+ level (1 mM) directed the C flux from ethanol to xylitol, with no effect on xylose consumption rate. The addition of pyrazole, an alcohol dehydrogenase (ADH) inhibitor, had the same effect, even in conditions of Mg2+ excess (4 mM), indicating a negative interaction between ADH and Mg2+ ions (p << 0.01). Cells grown either with pyrazole or Mg limitation increased their intracellular NADH concentration about 3 times, but displayed no significant differences in ADH specific activities (1,000 U/mg protein, +/- 10%). In contrast, no interaction was measured between Mg and antimycin A, excluding the possibility that Mg2+ limitation interferes with respiration.
authors.affiliation: Department of Industrial Microbiology and Biotechnology, Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
authors.forename: G
authors.initials: G
authors.lastname: Mahler
authors.forename: C
authors.initials: C
authors.lastname: Nudel
mesh_terms: D000426:Alcohol Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism; D003470:Culture Media; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology*; D009243:NAD / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects*; D010843:Pichia / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D014993:Xylitol / Q000378:metabolism
chemical_list: D003470:Culture Media; D009243:NAD; D000431:Ethanol; D000426:Alcohol Dehydrogenase; D008274:Magnesium; D010100:Oxygen; D014993:Xylitol