MICROBIOLOGICAL DEGRADATION OF BILE ACIDS

V. ON A PRINCIPAL INTERMEDIATE IN THE BREAKDOWN OF CHOLIC ACID BY STREPTOMYCES

Abstract

1. The culture conditions for the formation of a new unsaturated C-22 acid (presumably 7α-hydroxy-3, 12-diketo-Δ⁴-bisnorcholenic acid) from cholic acid by S. gelaticus 1164 were investigated by shake bottle culture.
2. All of the seven Streptomyces spp. which were identified in the previous paper (6) degraded cholic acid through an intermediate containing 7α-hydroxy-3-keto-Δ⁴-ene grouping. This fact was confirmed through the spectrophotometric analyses of the cultures.
3. Ability of the above seven Streptomyces spp. to utilize the various kinds of bile acids was investigated and it was found that the bile acids containing three functional groups at C₃, C₇ and C₁₂ were utilized except norcholic and homocholic acids. This fact suggests that the utilization of bile acids by Streptomyces is dependent on both the nucleus constitution and the length of side chains of bile acid.
4. An oxidative pathway of cholic acid by Streptomyces was discussed.
The authors express their hearty thanks to Prof. T. Shimizu and Prof. S. Mizuhara for their kind guidances.