Method for preparing dexamethasone intermediate product through one-step microbial fermentation and transformation

The invention belongs to the technical field of bio-pharmaceuticals, and in particular relates to a method for producing a dexamethasone epoxide hydrolysate through one-step microbial fermentation and transformation. According to the method, with 16a-methyl-17[alpha],21-dihydroxypregna-4-ene-9,11-epoxy-3,20-dione-21 acetate as a substrate, the dexamethasone epoxide hydrolysate is directly produced mainly by conducting mixed fermentation by virtue of arthrobacter simplex and bacillus megatherium. In comparison with the prior art, the method provided by the invention, on the basis of a synergistic effect between mixed strains, integrally combines two steps of reactions, namely dehydrogenation and hydrolysis, so that the finished dexamethasone epoxide hydrolysate is directly obtained; and the product has the advantages of being short in production cycle, high in bio-transformation rate, high in yield, environment-friendly and low in cost.