MICROBIOLOGICAL DEGRADATION OF BILE ACIDS

Abstract

Streptomyces was cultivated in a medium containing 0.2% (NH4) 2SO4, 0.1%K2HPO4, 0.05% MgSO4.7H2O, 0.001% FeCl3.6H2O at pH 7.2 and 27[degree]C, for 20 days. The production of C22-acids when supplemented with Na cholate at concentration of 0.05-0.8% FeC13.6H2O at pH 7.2 and photometrically at 246m[mu]. On yielding C22-acids, the acid precipitation and Pettenkopfer tests became negative. The absorption peak of the medium rich in C22-acids was shifted to 290 m[mu] on adding NaOH or HC1. 3,7,12-Trihydroxy derivatives (taurocholate, glycocholate, cholate, dehydrocholate), except for homo-, nor- and bisnor-cholate, were utilized as C sources by all of the species of Streptomyces tested (S. scabies, S. halstedii, S. rubescens, S. nitrosporeus, S. califoricus, S. flavogriseus, S. gelaticus 1164). The 3-monohydroxy derivative (lithocholate) was metabolized by 5 of the species excluding S. halstedii and S. nitrosporeus, while bisnor-cholate was utilized only by S. rubescens, S. flavogriseus, and S. gelaticus 1164. Results indicate that the main intermediary unsaturated C22-acid may be 7-[alpha]-hydroxy-3-keto- [DELTA] 4-ene derivative.