Steroid hydroxylations with Botryodiplodia malorum and Colletotrichum lini

An improved procedure for the microbial hydroxylations of dehydroepiandrosterone (DHEA, 1) and 15β,16β-methylene-dehydroepiandrosterone (2) was studied using whole cells of Botryodiplodia malorum and Colletotrichum lini. C. lini catalyzed 7α- and 15α-hydroxylation of 1 and 7α-hydroxylation of 2, while B. malorum gave 7β-hydroxylation of both the substrates. The stability of the enzymatic activity was higher in the presence of co-substrates (i.e., glucose or mannitol) allowing for repeated batches of the biotransformations. The yields of 7α,15α-dihydroxy-1 production were improved obtaining 5.8 g l−1 (recovered product) from 7.0 g l−1 of substrate. The structures of the hydroxylated products were assigned by a combination of two-dimensional NMR proton–proton and proton–carbon correlation techniques.