The Miraculous of Rhizopus arrhizus in the Structural Modifications of Steroidal Skeleton

Many natural and synthetic steroidal compounds have been converted by biotransformation to get highly valuable products for pharmaceuticals or chemical intermediates for the production of drugs. This review summarizes the biotransformation of sixty-six steroids 1-66 (ten of pregnane 1-10, fifty of androstane 11-60 while six steroids of estrane series 61-66) by using different strains of <i>Rhizopus arrhizus</i>, a well-known fungus of the zygomycetes group, used in food, dairy, pharmaceutical and numerous biotechnological processes. <i>R. arrhizus</i> transformed only fifty-four compounds 1-51 and 61-63, whereas nine compounds of androstane 52-60 and three compounds of estrane series 64-66 remained unchanged. <i>R. arrhizus</i> brought various structural modifications in steroids, including hydroxylation, epoxidation, epoxide hydrolysis, reduction of double bonds and ketonic group, dechlorination and defluorination, deacetylation, oxidation of various functional groups and isomerization.