POTENTIALITIES OF ZEOLITES FOR IMMOBILIZATION OF ENZYMES IN CONDUCTOMETRIC BIOSENSORS

Abstract

Conductometric biosensors based on urease and glucose oxidase immobilized with different types of zeolites have been investigated and compared. For this purpose, zeolite A, zeolite Y, Silicalite-1 (spherical), Silicalite-2, H+Beta 300, H+Beta 150 and NH4+Beta 25 were compared as potential carriers for enzyme immobilization. The parameters to obtain optimized biosensor performance were studied by investigating the percentage of zeolite in membrane, immobilization time in glutaraldehyde vapor and pH of the environment. Different zeolite types resulted in different enzymatic responses. In particular, we have demonstrated that the urease immobilized on silicalite-2 had better performance than immobilized urease without zeolite. Conductometric biosensor with glucose oxidase immobilized with NH4+Beta 25 zeolite had similar response values compared with immobilised enzyme without zeolite. The results obtained show that zeolites could be used as alternatives for enzyme immobilization in conductometric biosensors development.