Search and discovery of actinobacteria capable of transforming deoxycholic and cholic acids

Publication date: Available online 26 December 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): N.O. Deshcherevskaya, T.G. Lobastova, V.V. Kollerov, A.V. Kazantsev, M.V. Donova The capability of 54 selected actinobacteria strains of different phyla to convert deoxycholic (DCA) and cholic (CA) acids under aerobic conditions was studied. Except for the two species, the strains did not grow on DCA (1g/l) as a sole carbon source, but some of them effectively converted DCA performing 7β- and 9α- hydroxylation, 3α- and 12α-dehydrogenation, partial cleavage of the isoprenoic side chain and Δ4-dehydrogenation. Ursocholic acid, 9α-hydroxy-3,12-dioxo-23,24-bisnorchol-4-ene-22-oic acid, 3-keto-DCA and other end metabolites had been firstly identified in the actinobacteria strains. The total yield of 12α-hydroxy-3-oxo-chol-4-ene-24-oic and 3,12-dioxochol-4-ene-24-oic acids from DCA with Rhodococcus erythropolis VKM Ac-1152 reached 95%. Almost 80% DCA were converted to 9α-hydroxy-3,12-dioxo-23,24-bisnorchol-4-en-22-oic acid by Rhodococcus sp. MTS-77. Unlike DCA, cholic acid (CA) was confirmed to be a growth substrate for majority of the examined strains, but only three Rhodococcus strains exhibited 7α- and/or 12α-HSDH activities thus forming 7-keto-DCA and 12-keto-chenodeoxycholic acid as major products from CA. Steroid metabolites were identified by TLC, GC, MS, 1H- and 13C NMR analyses. The results may contribute to the knowledge of biocatalytic potent...

Source: Journal of Molecular Catalysis B: Enzymatic - January 7, 2017 Category: Biochemistry Source Type: research