Kinetic of carbonic anhydrase immobilized onto amberlite xad 7 and it application in sequestration of co2 into caco3 precipitate

Abstract

Carbonic Anhydrase (CA) was immobilized onto Amberlite XAD 7 and was used in carbon dioxide sequestration purposes. The catalytic activities for free and immobilized CA were estimated by using para-Nitrophenyl Acetate (p-NPA) as the substrate in Tris-buffer containing 10% of acetonitrile. Lineweaver-Burk plot was employed to estimate the Michaelis-Menten kinetic parameters for both free and immobilized CA. Km value of free and immobilized CA were 2.92 mM and 5.7 mM respectively. Meanwhile the Vmax value of free and immobilized CA were 5.95 μmoles/min/ml and 2.67 μmoles/min/ml respectively. The kinetic value obtained in the present study shown that the immobilized CA has high affinity for its substrate. On the other hand, activity and stability study at various pH and temperature indicates that the optimum pH for free CA was found to be at pH 9 while for immobilized CA was at pH 10. For optimum temperature, a free CA was performed optimally at temperature 25°C and immobilized CA was working effectively at temperature 50°C. The immobilized CA onto Amberlite was tested in the CO2 sequestration process and the formation of the white CaCO3 precipitate was observed during the process. CaCO3 powder obtained during the process was validated with the XRD analysis. The finding indicated that immobilized CA onto Amberlite XAD7 retained it enzymatic activity and stability and thus perform well in the CO2 sequestration which gave the white CaCO3 precipitate.