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Updated: Oct 3, 2026

Enzymatic Synthesis of Epoxidized Metabolites of Docosahexaenoic, Eicosapentaenoic, and Arachidonic Acids
Published on: June 28, 2019
7alpha-OH epimerisation of bile acids via oxido-reduction with Xanthomonas maltophilia
Alessandro Medici1, Paola Pedrini, Ercolina Bianchini
1Dipartimento di Chimica, Università di Ferrara, Via L. Borsari 46, I-44100, Ferrara, Italy. mda@dns.unife.it
Abstract:
The microbial 7alpha-OH epimerisation of cholic, chenodeoxycholic, and 12-ketochenodeoxycholic acids (7alpha-OH bile acids) with Xanthomonas maltophilia CBS 827.97 to corresponding 7beta-OH derivatives with scarcity of oxygen is described. With normal pressure of oxygen the 7-OH oxidation products are obtained. No biotransformations are achieved in anaerobic conditions. The microbial 7alpha-OH epimerisation is achieved by oxidation of 7-OH function and subsequent reduction. Partial purification, in fact, of the enzymatic fraction revealed the presence of two hydroxysteroid dehydrogenases (HSDH) alpha- and beta-stereospecific together with a glycocholate hydrolase. On the basis of these results a further application is the microbial reduction of 6alpha-fluoro and 6beta-fluoro-3alpha-hydroxy-7-oxo-5beta-cholan-24-oic acid methyl esters to the corresponding 7alpha-OH and 7beta-OH derivatives.
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