Fig. 1From: Co-production of 11α-hydroxyprogesterone and ethanol using recombinant yeast expressing fungal steroid hydroxylasesSteroid chemical structure. a Gonane, the steroid nucleus comprising three cyclohexane rings (rings A, B, and C) and one cyclopentane (ring D) labeled using the IUPAC-recommended ring-lettering and atom-numbering. b Hydroxylation of progesterone to 11α-hydroxyprogesteroneBack to article page