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.