Nine hydroxy-derived androstadiene compounds were isolated from the fermentation broth of Neurospora crassa when incubated in the presence of androst-1,4-dien-3,17-dione (ADD; I) for 7 days. Hydroxylations at 6b, 7b, 11a, 14a-positions and 17-carbonyl reduction of the substrate were the characteristics observed in this biotransformation. Their structures were determined by spectroscopic methods as 17b-hydroxyandrost-1,4-dien-3-one (II), 14a-hydroxyandrost-1,4-dien-3,17-dione (III), 6b-hydroxyandrost-1,4-dien-3,17-dione (IV), 11a-hydroxyandrost-1,4-dien-3,17-dione (V), 6b,17b-dihydroxyandrost-1,4-dien-3-one (VI), 7b-hydroxyandrost-1,4-dien-3,17-dione (VII), 14a,17b-dihydroxyandrost-1,4-dien-3-one (VIII), 6b,14a-dihydroxyandrost-1,4-dien-3,17-dione (IX), and 11a,17b-dihydroxyandrost-1,4-dien-3-one (X). A new steroid substance, 6b,14a-dihydroxyandrost-1,4-dien-3,17-dione (IX), was also characterized during this study. The best fermentation condition was found to be 7-day incubation at 258C and pH values of 5.0 Á6.0 in the presence of 0.05 g 100 mL (1 of the substrate. At a concentration above 0.075 g 100 mL (1 , the biotransformation was completely inhibited.
