High-rate membrane supported aqueous-phase enzymatic conversion in organic solvent.

Microporous membranes were used as a support material for enzyme immobilization by a supported aqueous-phase. To test the concept, a model reaction was chosen involving the oxidation of p-cresol by tyrosinase. Tyrosinase was first immobilized in a thin film of water formed on the inner surface of the membrane and then allowed to catalyze p-cresol oxidation in chloroform. By choosing optimal operating conditions, tyrosinase functioned catalytically for more than 6 hours with a stable reaction rate. The reaction rate was highly dependent on water content (water wt./enzyme wt. ratio) and permeation flux. Also, enzyme loading was an important factor for maintaining stable activity. This type of high-rate reactor utilized convective flow through an enzyme immobilized microporous membrane and provided high productivity by reducing mass transport limitations.