[Steroid transformation with immobilized microorganisms. I. Transformation of cholesterol to cholestenone in organic solvents].

The transformation of cholesterol to cholest-4-ene-3-one has been investigated in the presence of toluene and carbontetrachloride using cells of Nocardia erythropolis (IMET 7185) immobilized by different methods. The adsorption on DEAE-cellulose has been observed to be the most effective method. The stability of immobilized cells relating to cholesteroloxydase activity, transformation capacity, and the influence of water have been investigated.