Biotransformations of epiandrosterone (1), dehydroepiandrosterone (2), testosterone (3), progesterone (4) and pregnenolone (5) by Aspergillus tamarii MRC 72400 for 5 days have been reported and the results of these incubations have been compared with previously published data obtained with Aspergillus tamarii QM 1223. A. tamarii MRC 72400 showed higher Bayer–Villiger monooxygenase activities than A. tamarii QM 1223 did. Apart from pregnenolone (5), A. tamarii MRC 72400 metabolized these steroids in different ways. Incubation of epiandrosterone (1) afforded 3ß,11ß-dihydroxy-5?-androstan-17-one (6) (3%) and 3ß-hydroxy-17a-oxa-D-homo-5?-androstan-17-one (7) (9.5%). Incubation of dehydroepiandrosterone (2) afforded 3ß-hydroxy-17a-oxa-D-homoandrost-5-en-17-one (8) (28%), testolactone (9) (6%), 3ß,7ß-dihydroxyandrost-5-en-17-one (10) (13%) and 3ß,7?-dihydroxy- androst-5-en-17-one (11) (24%). Incubation of testosterone (3) afforded testolactone (9) (58%). Incubation of progesterone (4) also afforded testolactone (9), however in higher yield (86%). Incubation of pregnenolone (5) afforded 3ß-hydroxy-17a-oxa-D-homoandrost-5-en-17-one (8) (25%) and testolactone (9) (27%).
The biotransformations of testosterone, epiandrosterone, progesterone and pregnenolone by Aspergillus terreus MRC 200365 for five days were described. The biotransformation of testosterone afforded testolactone. The biotransformation of epiandrosterone afforded 3ß-hydroxy-17a-oxa-D-homo-5?-androstan-17-one. The biotransformation of progesterone afforded androst-4-ene-3,17-dione and testolactone. The biotransformation of pregnenolone afforded 3ß-hydroxy-17a-oxa-D-homoandrost-5-en-17-one and testolactone.
