ACTIVITY AND STABILITY OF AN ENTRAPPED-CELL SYSTEM FOR THE DELTA-1-DEHYDROGENATION OF STEROIDS IN ORGANIC MEDIA

Whole Arthrobacter simplex cells entrapped in kappa-carrageenan or in two types of polyurethane foam, or adsorbed on silanized Celite, were tested for the DELTA1-dehydrogenation of hydrocortisone and its derivatives in organic media. Catalytic activity and stability levels were evaluated for the immobilized cells in buffer with 2.5% (vol/vol) methanol, and in three buffer-saturated solvents (n-octan-1-ol, n-decan-1-ol, and chloroform). The addition of glutamate to the immobilization support stabilized the activity of the immobilized cells in the tested organic media. The system with polyurethane (HYPOL 6100)-entrapped cells (with coimmobilized glutamate) in n-decan-1-ol provided the highest long-term activity levels. Several factors involved in the polyurethane-entrapment procedure were also studied.