ADVANCES IN MICROBIAL BIOTECHNOLOGY OF BILE-ACIDS

The recent advances in microbial biotechnology of production of bile a cid metabolites helped to identify a number of neutral and acidic ster oidal compounds useful as drugs and drug intermediates on a scale whic h would not have been possible by classical chemical transformations. Microbial transformations viz., hydroxylation, dehydroxylation, reduct ion of the carbonyl moieties, epimerization, side-chain metabolism, in troduction of carbon-carbon double bonds into the steroid nucleus, dec onjugation of bile acid conjugates carried out by various microorganis ms for production of useful metabolites with special reference to newe r techniques including cell immobilization and transposon mutagenesis for selective transformations are reviewed. The different pathways of microbial degradation of bile acids leading to the formation of variou s products are discussed. A compilation of the metabolites formed by v arious microorganisms from the bile acids or their conjugates and repo rted during the period 1979-1992 is also provided.