Metabolic changes in Clostridium absonum ATCC 27555 accompanying induction of epimerization of a primary bile acid.
Some parameters of fermentation have been determined for Clostridium absonum in a chemostat by using a chemically defined medium with glucose as the sole source of carbon and energy. Steady-state continuous cultures were achieved at two dilution rates (D). Trends of the carbon flow were determined by comparison of ratios between the specific rates of formation of the three products of metabolism (lactate, acetate, butyrate). Chenodeoxycholate induced the 7alpha- and 7beta-hydroxysteroid dehydrogenases of C. absonum. In the presence of this inducer, the growth yield and the carbon recovery decreased, the carbon flow distribution was altered favoring acetate production, and a deficit in the reoxydation of nucleotidic cofactors was observed. In the presence of chenodeoxycholate, C. absonum would favor the production of energy at the expense of the reoxidation of nucleotidic cofactors so as to ensure its growth, and the epimerization of chenodeoxycholate to ursodeoxycholate.
Warchol
Magda
M
Laboratoire de Biochimie des Bactéries Gram+, Université Henri Poincaré-Nancy I, Faculté des Sciences et Techniques, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France.
Car
Ludovic
L
Grill
Jean-Pierre
JP
Schneider
François
F
D019342:Acetic Acid / Q000378:metabolism; D002087:Butyrates / Q000378:metabolism; D002635:Chenodeoxycholic Acid / Q000378:metabolism*; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism*; D003067:Coenzymes / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004790:Enzyme Induction; D005947:Glucose / Q000378:metabolism; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014580:Ursodeoxycholic Acid / Q000378:metabolism*
D002087:Butyrates; D003067:Coenzymes; D003470:Culture Media; D002635:Chenodeoxycholic Acid; D019344:Lactic Acid; D014580:Ursodeoxycholic Acid; D006913:Hydroxysteroid Dehydrogenases; D005947:Glucose; D019342:Acetic Acid