BAEYER-VILLIGER OXIDATION OF SOME STEROIDS BY Aspergillus tamarii MRC 72400

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 3 beta, 11 beta-dihydroxy-5 alpha-androstan-17-one (6) (3%) and 3 beta-hydroxy-17a-oxa-D-homo-5 alpha-androstan-17-one (7) (9.5%). Incubation of dehydroepiandrosterone (2) afforded 3 beta-hydroxy-17a-oxa-D-homoandrost-5-en-17-one (8) (28%), testolactone (9) (6%), 3 beta, 7 beta-dihydroxyandrost-5-en-17-one (10) (13%) and 3 beta, 7 alpha-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 3 beta-hydroxy-17a-oxa-D-homoandrost-5-en-17-one (8) (25%) and testolactone (9) (27%).