Transformation of progesterone by a thermophilic bacillus

When a thermophilic bacillus was incubated with progesterone for approx. 18 h at 65°C, four progesterone-based metabolites were produced in moderate quantities. Two products were found to be hydroxy derivatives, i.e. 6α-hydroxyprogesterone and 6β-hydroxyprogesterone and two were C-20 reduced epimers of progesterone, i.e. 20α- and 20β-dihydroprogesterone. 6α-Hydroxyprogesterone is a rare microbial transformation product. Inhibition of hydroxylation by azole-based fungicides and the presence of a carbon-monoxide-reduced difference-spectrum absorbance maximum at 448 nm in the soluble cell fraction suggest that the hydroxylase(s) might be cytochromes(s) P450. The dihydroprogesterones were probably produced by oxidoreductases.