Effect of cell immobilization and organic solvents on sulfoxidation and steroid hydroxylation by Mortierella isabellina.

The effects of calcium alginate bead immobilization and the presence of organic solvents on two bioconversion reactions carried out by Mortierella isabellina ATCC 42613 have been investigated. These reactions, the 14 alpha-hydroxylation of progesterone and the sulfoxidation of thioanisole, both proceed in high yield using resting-cell bioconversions, but are not carried out by alginate bead preparations in the absence of an organic co-solvent, the best results being obtained with 5 or 10% aqueous methanol. The stereoselectivity of sulfoxidation of thioanisole was found to be dependent upon the nature and concentration of organic co-solvent.