Solid Phase Microbial Fermentation of Anabolic Steroid, Dihydrotestosterone with Ascomycete Fungus Fusarium Oxysporum

Objective: Microbial catalysis is used in the commercial production of many bioactive steroids. Solid phase microbial fermentation of anabolic steroid, dihydrotestosterone (DHT, 1), was carried out with ascomycete fungal strain Fusarium oxysporum (NRRL-1392). Methods: Sabouraud-4% glucose-agar was used to cultivate the fungal cultures as solid phase medium. Substrate 1 was incubated with Fusarium oxysporum (NRRL-1392) for 8 days. Microbial transformed metabolites were purified by using column chromatographic technique. Results: Ascomycete fungal strain Fusarium oxysporum (NRRL-1392), transformed dihydrotestosterone (1) to four oxidative metabolites 2-5 using solid phase microbial transformation metod. During biotransformation process the hydroxy group was incorporated in inactivated methine carbon atoms at C-7 and C-11 positions. Their structures were elucidated by means of a homo and heteronuclear 2D NMR and by HREI-MS techniques as 17βhydroxyandrosta-1, 4-dien-3-one 2, androsta-1, 4-diene-3, 17-dione 3, 7α, 17β-dihydroxyandrosta-1, 4-dien-3-one (4), and 11α-hydroxyandrosta-1, 4diene-3, 17-dione 5. The relative stereochemistry of newly incorporated hydroxy groups were deduced by 2D NOESY experiment. Conclusion: In conclusion, microbial biocatalysis is an attractive alternative tool for the preparation of new bioactive steroids, which might be difficult to prepare by conventional chemical routes. Furthermore, microbial-catalyzed biotransformations can produce commercially valuable steroidal pharmaceuticals for the pharmaceutical industry.