Factors affecting the biotransformation of chlormadinone acetate to delmadinone acetate

Factors affecting the aqueous biotransformation of chlormadinone acetate to delmadinone acetate by freely suspended cells of Arthrobacter simplex ATCC 6946 and Bacillus sphaericus ATCC 13805 were investigated. The effects of exogenous electron carrier (menadione), cosolvent (dimethylformamide), steroid inducer (hydrocortisone), surfactant (Tween 80) and alternative carbon source (d-(+)-glucose), on the production yield of delmadinone acetate were identified. The biotransformations were performed in shaken flasks at 25±2 °C for 72 h. The optimal conditions for the biotransformation with A. simplex were: 0.25 mM chlormadinone acetate, 5% DMF, 0.41 mM hydrocortsione and 0.75% (w/v) Tween 80. With B. sphaericus, the optimal conditions were: 0.6 mM menadione, 0.12 mM chlormadione acetate, 5% DMF, 0.41 mM hydrocortisone and 0.25 g dm−3 d-(+)-glucose. Under optimal conditions, the product yields were 28.7 and 36.9% for A. simplex and B. sphaericus biotransformations, respectively.