HIGHLY EFFICIENT ENZYME RECOVERY USING A POROUS MEMBRANE WITH IMMOBILIZED TENTACLE POLYMER-CHAINS

We describe a novel ''tentacle-type'' porous membrane that allows adso rption of enzymes in multilayers in amounts about 50-fold those permit ted by monolayer adsorption. A diethylamino (DEA) group as an anion-ex changer was appended to a polymer chain, grafted onto the pores of a h ollow-fiber membrane. A urease solution was forced to permeate through the pores of the anion-exchange membrane, which had a DEA group densi ty up to 2.9 mmol per gram of membrane and a thickness of 0.8 mm. The grafted chain with a higher DEA group density provided a larger number of three-dimensional adsorption (tentacle-like binding) sites for ure ase. The binding capacity exceeded one gram of urease per gram of the membrane at DEA group densities higher than 1.6 mmol per gram, which a mounted to a more than 37-fold greater amount of adsorbed enzyme compa red to monolayer adsorption. In addition, urease captured by the DEA o n the graft chain could be quantitatively eluted with retention of 90% of the feed urease activity.