Biotransformation of ursodeoxycholic acid by Pseudomonas sp NCIB 10590.

The metabolism of ursodeoxycholic acid by Pseudomonas sp NCIB 10590 has been studied in phosphate-buffered mineral salts. The organism completely metabolized ursodeoxycholic acid in 24 hr, and time-course experiments revealed that maximum product formation occurred at 14 hr. The major products detected and identified at 14 hr were 7 beta-hydroxychol-4-en-3-one-24-oic acid, 7 beta-hydroxy-3-oxo-pregna-1,4-diene-20-carboxylic acid, and 7 beta-hydroxyandrosta-1,4-diene-3,17-dione. Several minor intermediates were isolated and evidence is given for the following structures: 7 beta-hydroxy-5 beta-cholan-3-oxo-24-oic acid, 7 beta-hydroxyandrost-4-en-3,17-dione, 7 beta,17 beta-dihydroxyandrosta-1,4-diene-3-one, 3-hydroxy-1,3,5(10)-9,10-seco-androstatriene-3,17-dione-7 beta-ol, and 22 alpha-hydroxymethylpregna-1,4-diene-3-one-7 beta-ol.