Bioconversion and binding of sterols by thermophilic moulds

None of the fourteen thermophilic moulds was able to break down the aliphatic side chain of sterols, viz. cholesterol, lanosterol, sitosterol, and stigmasterol so as to yield 4-androstene-3,17-dione, 1,4-androstadiene-3,17-dione and progesterone. In Acremonium alabamensis and Talaromyces emersonii, cholestenone was detected as a product of fermentation of cholesterol whereas the former yielded stigmastadienone from stigmasterol and sitosterol. Lanosterol appeared to be resistant to fungal bioconversion. All the thermophilic moulds exhibited avidity for binding sterols to the mycelium, but the ability to bind sterol seemed to depend upon the nature of the organism and the sterol.