IMMOBILIZTION OF ORGANOPHOSPHORUS HYDROLASE ENZYME ON FERRIC MAGNETIC NANOPARTICLES AND INVESTIGATION OF IMMOBILIZED ENZYME STABILITY

摘要

In the present study, organophosphorus hydrolase enzyme on Functionalized ferric magnetic nanoparticles was immobilized by the covalent binding method. The Optimized amount for parameters of mg EDAC/mg nanoparticles, enzyme units (U)/mg nanoparticles, reaction time, and pH were determined to be 6.125, 0.1341, 3 h and 6.15 respectively. The amount of immobilization yield according to the enzyme activity was obtained to be 70% and also the amount of immobilized enzyme on nanoparticles was 0.25 U/mg nanoparticles. Stability studies showed significant increase in immobilized enzyme stability at 4, 25 and 45°C. The stability of Immobilized enzyme showed a 6.3-fold increase in comparison to free enzyme at 4°C. The results demonstrated that the pH stability of the immobilized enzyme significantly increased in comparison with free enzyme. The immobilized enzyme was usable and recoverable for seven cycles. The results depicted that 80% of enzyme activity was retained after fifth cycle. FTIR test showed the covalent binding of enzyme to magnetic nanoparticles’ surface and the modified enzyme magnetic nanoparticles property was superparamagnetic by vibrating sample magnetometer test.