Fungal transformation of methyltestosterone by the soil ascomycete Acremonium strictum to some hydroxy derivatives of 17-methylsteroid

The ascomycete Acremonium strictum was used for the biotransformation of methyltestosterone (1), a pharmaceutical steroid substance, into some steroid derivatives (6β-hydroxy-17α-methyltestosterone (2), 6β,12β-dihydroxy-17α-methyltestosterone (3), 7β-hydroxy-17α-methyltestosterone (4), 6β,17β-dihydroxy-17α-methylandrosta-1,4-dien-3-one (5), and 3,17β-dihydroxy-17α-methylestra-1,3,5(10)-triene (6). The fermentation was carried out in Sabouraud-dextrose broth (SDB) supplemented with 1 mM of the substrate, and the temperature and aeration rate were adjusted to 30°C and 150 rpm, respectively. The biotransformation characteristics observed were hydoxylations at C-6β, C-7β, and C-12β, 1,2-dehydrogenation, and ring A aromatization. The best fermentation conditions, such as temperature, substrate concentration, pH, incubation period, and aeration, were found to be 25°C, 1 mM, pH 6.5, 6 days, and 150 rpm, respectively, for maximum biotransformation of 1.