Microbial transformation of diosgenin and its precursor furostanol glycosides

Microorganisms have been screened for biotransformational activity against diosgenin or its precursor furostanol glycosides obtained from fenugreek seed (Trigonella foenum-graecum). Using diosgenin as the substrate, Cunninghamella elegans and Aspergillus nidulans produced some androstenes when α,α'-dipyridyl was supplemented to the transformation medium. Also, using the glycosides as a substrate, Rhizopus sp. produced diosgenin in >90% yield from the glycoside. The parameters were optimized to increase the yield of the androstenes.