Transformation of 3β-hydroxy-5-en-steroids by Mucor racemosus

The course of the transformation of three 3β-hydroxy-5-en-steroids with varying substituents at C-16 or/and C-17 by Mucor racemosus was first investigated. All the examined substrates were transformed, mainly 7α-hydroxylated. The fermentation of 3β-hydroxy-5-en-steroids with C16-C17 double bond or 16α, 17α-epoxy resulted in the formation of 16α-methyloxy-steriods. The characterization of the metabolites was performed by various spectroscopic methods such as IR, MS, 1H NMR, 13C NMR and 2D NMR. The relationships between the substrate structures and hydroxylated positions were also discussed.