Epimerization of chenodeoxycholic acid to ursodeoxycholic acid by Clostridium baratii isolated from human feces

• Published in: FEMS microbiology letters Vol. 235; no. 1; pp. 65 - 72
• Main Authors: Lepercq, Pascale, Gérard, Philippe, Béguet, Fabienne, Raibaud, Pierre, Grill, Jean-Pierre, Relano, Purification, Cayuela, Chantal, Juste, Catherine
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2004; Blackwell; Oxford University Press; Wiley-Blackwell
• Subjects: Acids; Aged; Bacteria; Bile; Bile acid epimerization; Bioconversion; Biological and medical sciences; Chenodeoxycholic acid; Chenodeoxycholic Acid - chemistry; Chenodeoxycholic Acid - metabolism; Clostridium; Clostridium - isolation & purification; Clostridium - metabolism; Clostridium baratii; DNA sequencing; domain_sdv.mp.prb; domain_sdv.mp.prb.bif; Feces; Feces - microbiology; Fundamental and applied biological sciences. Psychology; Homology; Human intestinal microbiota; Humans; Isomerism; Life Sciences; Male; Microbiology; Microbiology and Parasitology; Ribosomal DNA; Ursodeoxycholic acid; Ursodeoxycholic Acid - chemistry; Ursodeoxycholic Acid - metabolism; Bile acid epimerization; Chenodeoxycholic acid; Human intestinal microbiota; Ursodeoxycholic acid; Clostridium; Human; Digestive system; Clostridium baratii; Gut; Clostridiales; Microflora; Bile acid; Clostridiaceae; Bacteria; Feces
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2004.tb09568.x

Abstract Ursodeoxycholic acid-producing bacteria are of clinical and industrial interest due to the multiple beneficial effects of this bile acid on human health. This work reports the first isolation of 7-epimerizing bacteria from feces of a healthy volunteer, on the basis of their capacity to epimerize the primary bile acid, chenodeoxycholic acid, to ursodeoxycholic acid. Five isolates were found to be active starting from unconjugated chenodeoxycholic acid and its tauro-conjugated homologue, but none of these strains could epimerize the glyco-conjugated form. Biochemical testing and 16S ribosomal DNA sequencing converged to show that all five isolates were closely related to Clostridium baratii (99% sequence similarity), suggesting that this bacterial species could be responsible at least partially, for this bioconversion in the human gut.