Immobilization of carbonic anhydrase on epoxy-functionalized magnetic polymer microspheres for CO2 capture

• Epoxy-functionalized magnetic polymer microspheres were synthesized for CA immobilization.
• The immobilized CA presented a higher stability and reusability than free CA.
• The immobilized CA had a high magnetism and a good CO2 capture capacity.

Carbonic anhydrase (CA) is the most efficient catalyst for CO2 hydration and dehydration. In the present work, magnetic polymer microspheres functionalized with epoxy group were prepared, and CA enzyme was immobilized on the carries by selective covalent binding. The parameters affecting CA immobilization, such as pH, temperature and enzyme dose were investigated. Based on the investigation and the characterization of the microspheres, the kinetic parameters of the immobilized and the free CA were also evaluated. The value of the Michaelis–Menten constant (Km) and the maximum velocity (Vmax) of the immobilized CA was 8.077 mmol/L (mM) and 0.027 μmol/(min mL), while that of the free CA was 6.091 mM and 0.091 μmol/(min mL), respectively. Moreover, the performance of the thermal stability, storage stability and reusability of the immobilized CA confirmed that CA immobilized on the epoxy-functionalized magnetic polymer microspheres owned a stable and efficient catalytic ability on CO2 hydration, which seemed to be a suitable candidate for CO2 capture.

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