Microbial 7alpha-hydroxylation of 3-ketobisnorcholenol.

The transformation of 22-hydroxy-23,24-bisnorchol-4-en-3-one to 7alpha-22-dihydroxy-23,24-bisnorchol-4-en-3-one by Botryodiploida theobromae, Lasiodiplodia theobromae, and various Botryosphaeria strains is described. Factors affecting the reaction were incubation temperature, sonication of the substrate, and addition of 2,2'-dipyridyl, extra carbohydrate, and Amberlite XAD-7. The enzyme responsible for the reaction appeared to be very specific and was not characteristic of all members of the genera listed above.