| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2029310 | Steroids | 2011 | 14 Pages |
The potential of Fusarium oxysporum var. cubense UAMH 9013 to perform steroid biotransformations was reinvestigated using single phase and pulse feed conditions. The following natural steroids served as substrates: dehydroepiandrosterone (1), pregnenolone (2), testosterone (3), progesterone (4), cortisone (5), prednisone (6), estrone (7) and sarsasapogenin (8). The results showed the possible presence of C-7 and C-15 hydroxylase enzymes. This hypothesis was explored using three synthetic androstanes: androstane-3,17-dione (9), androsta-4,6-diene-3,17-dione (10) and 3α,5α-cycloandrost-6-en-17-one (11). These fermentations of non-natural steroids showed that C-7 hydroxylation was as a result of that position being allylic. The evidence also pointed towards the presence of a C-15 hydroxylase enzyme.The eleven steroids were also fed to Exophialajeanselmei var. lecanii-corni UAMH 8783. The results showed that the fungus appears to have very active 5α and 14α-hydroxylase enzymes, and is also capable of carrying out allylic oxidations.Ceratocystis paradoxa UAMH 8784 was grown in the presence of the above-mentioned steroids. The results showed that monooxygenases which effect allylic hydroxylation and Baeyer–Villiger rearrangement were active. However, redox reactions predominated.
Graphical abstractSubstrates were functionalised at sites indicated.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Re-examination of ability of three fungi to functionalise steroids. ► Use of pulse feeding protocol to induce cytochrome P450 enzymes. ► First report where Ceratocystis paradoxa has successfully hydroxylated a steroid. ► Investigation in which Baeyer–Villiger reaction was executed by C. paradoxa. ► Study where C. paradoxa carried out pregnane side chain cleavage.
