Investigation on the Immobilization of Carbonic Anhydrase and the Catalytic Absorption of Carbon Dioxide

Abstract

The optimum conditions, such as pH, immobilization time, temperature, and enzyme dose, for carbonic anhydrase (CA) immobilized on the polyester polyurethane prepolymer 80 were investigated. Simultaneously, the performances (e.g., pH, thermal, operational, and storage stabilities) of immobilized CA and free CA were compared. The results revealed that the optimum conditions, such as pH value of Tris–HCl buffer, immobilization time, temperature, and enzyme dose, of immobilized CA were 7.5, 24 h, 35 °C, and 1 mL of enzyme solution (0.1 mg/mL)/0.1 g of polyester 80, respectively. Moreover, pH and operational, thermal, and storage stabilities of immobilized CA were higher than those of free CA. On this basis, the experiment was conducted to immobilize CA to absorb CO2. The results indicated that the CO2 concentration, liquid/gas ratio, and gas flow rate may affect the properties of CO2 absorption. The CO2 absorption efficiency dropped from 63 to 42.7% with an increase in the CO2 concentration from 9 to 15.4%. W...