Approaches to improve the solubility and availability of progesterone biotransformation by Mucor racemosus

Substrate solubility in steroid biotransformation is critical for improving the biotransformation of hydrophobic substrates. The present investigation describes the effect of some organic solvents, polyoxyethylene sorbitan monooleate (Tween 80; surfactant) and beta-cyclodextrin (beta-CD), on the biotransformation of progesterone (PR) by Mucor racemosus. PR was transformed to three derivatives namely; 11 alpha-hydroxyprogesterone (11 alpha-HP) as main product (I), 4-pregnen-18-al-11 beta, 21-diol-3, 20-dione (Aldosterone) (II) and 20-hydroxy-pregnan-18-oic acid (III) as minor products. Among the tested organic solvents, methanol gave the highest total bioconversion effi ciency (T. B. E) of 75.0 +/- 2.49%. Tween 80 improved PR biotransformation up to 81.56 +/- 2.29%, while with an optimum molar ratio of PR to beta-CD of 1:1, the TBE was increased to 87.15 +/- 2.17% of the added substrate in presence of beta-CD. The interaction between PR and beta-CD in the inclusion complex was assessed using differential scanning calorimetry (DSC) and infrared (IR) spectra.