Microbial transformation of testosterone by Rhizopus stolonifer and Fusarium lini.

The microbial transformation of testosterone by the fungi Rhizopus stolonifer and Fusarium lini has been investigated for the first time. The bioconversion reactions observed from R. stolonifer included oxidation of a 17beta-hydroxyl group, a hydroxylation at equatorial 11alpha position, reduction of the double bond at C-4 with oxidation of the methylene at C-6 to the corresponding keto group, and lactonisation of ring D; the latter is the first report of this reaction by a Rhizopus species. Fusarium lini promoted 1-dehydrogenation of the steroid, which has been rarely observed in fungi cultures. The other routes of biotransformations included oxidation of the 17beta-hydroxyl group and the hydroxylation at 11alpha position. These reactions are not common for Fusarium species.