Immobilization of Glucose oxidase on Meso-porous Glass-ceramic with the Skeleton of CaTi4(PO¬4)6

Microporous glass ceramic with skeleton of CaTi4(PO¬4)6 with average pore size of 12.7 nm has been synthesized and used as a carrier of glucose oxidase. The glass ceramic was prepared by controlled heat treatment of glass samples, which causes the phase separation in their structure and creates CaTi4(PO¬4)6 and β-Ca3(PO4)2 phases. The β-Ca3(PO4)2 phase was dissolved by soaking the glass ceramics in HCl and CaTi4(PO¬4)6 built the skeleton of microporous glass ceramic. Analysis of the ability of the carrier for immobilization of glucose oxidase (GOx) was undertaken. Average amount of immobilized enzyme and percentage of enzyme activity on the carrier were 27 gr GOx/gr carrier and 60.15%, respectively. Effect of pH and temperature variations on the enzyme activity has been studied and results demonstrated that maximum activity for both free and immobilized enzyme was at T=40˚C and pH=7.0. Due to the same value of maximum activity, no serious conformational change of enzyme had taken place through immobilization. However, immobilization of GOx on CTP caused to considerable increase of enzyme stability under different environmental conditions.