Author:

Keywords:

Bile Acids and Salts, Biotransformation, Cholic Acids, Feces, Fusobacterium, Humans, Intestines, Science & Technology, Life Sciences & Biomedicine, Biotechnology & Applied Microbiology, Microbiology, 3107 Microbiology, 3207 Medical microbiology

Abstract:

We isolated two strains of an unnamed Fusobacterium species from human intestinal microflora, which stereospecifically transformed bile acid 3-sulfates into C-3-unsubstituted, ring A-unsaturated bile acids. Both 3 alpha- and 3 beta-sulfates of 5 beta-bile acids were metabolized to delta 3-5 beta-cholenoic acids; 3 beta-sulfates of 5 alpha-bile acids were converted into a mixture of delta 2-5 alpha-bile acids and 3 alpha-hydroxy-5 alpha-bile acids, whereas 3 alpha-sulfates of 5 alpha-bile acids were left intact. Unsulfated bile acids were not transformed into unsaturated derivatives. These strains differ from previously isolated intestinal bacteria, which desulfated bile acid sulfates without further transformation.