改性聚乙烯膜和氧化硅固定化碳酸酐酶

The activity of carbonic anhydrase (CA) immobilized by different methods was investigated using modified polyethylene (PE) membrane and silica (SiO₂) as carriers, and then modified with polydopamine/ polyethyleneimine (PDA/PEI) PE- and SiO₂-immobilized CA were used as research objects. The optimum reaction conditions and stability were investigated. The results show that under the same reaction conditions, the activity recovery of PDA/PEI-SiO₂ immobilized CA was the highest, which was 58.8%, and the activity recovery of PDA/ PEI-PE immobilized CA was 17.1%. Their retentive activities were 84.8% and 90.2%, respectively, after 10 use recycles. The optimum reaction conditions of immobilized enzymes were 35℃ and pH 8.5, which were the same as those of free enzymes. The stability of the two immobilized enzymes at higher temperature (55—65℃) and higher acid concentration (>0.010 mol/L) was better than that of free enzyme. Mg²⁺ could significantly promote the activity of free enzyme and immobilized enzyme, while K⁺ and Mg²⁺ had no obvious effect. PDA/PEI-SiO₂ and PDA/PEI-PE immobilized CA retained 95.2% 和 92.4% activity after stored at 4℃ for 10 d. When used in the CO₂ hydration reaction, the amount of CaCO₃ produced was 120% and 70% of free CA. The immobilized CA has great potential in the industrial application of CO₂ capture.