Immobilization and kinetics of catalase on calcium carbonate nanoparticles attached epoxy support

P. Preety, V. Hooda
M.D. University, IN

Keywords: catalase, Immobilization, CaCO3, epoxy, nanoparticles

Summary:

A novel hybrid epoxy/ nano CaCO3 composite matrix for catalase immobilization was prepared by polymerizing epoxy resin in the presence of CaCO3 nanoparticles. The hybrid support was characterized using scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Catalase was successfully immobilized onto epoxy/nano CaCO3 support with a conjugation yield of 0.67 mg/cm2 and 92.73 % retention of activity. Optimum pH and optimum temperature of free and immobilized catalase were found to be 7.0 and 35°C. The value of Km for H2O2 was higher for immobilized enzyme (31.42 mM) than native enzyme (27.73 mM). A decrease in Vmax value from 1500 μmol (min mg protein)-1 to 421.06 μmol (min mg protein)-1 was observed after immobilization. Thermal and storage stabilities of catalase improved immensely after immobilization. Immobilized enzyme retained three times than the activity of free enzyme when kept at 75°C for 1 h and the half life of enzyme increased five times when stored in phosphate buffer (0.01M, pH 7.0) at 5°C. The enzyme could be reused 30 times without any significant loss of its initial activity.