Cost-Effective Preparation of Carbonic Anhydrase with Superior Performance for Assisting Amine and Amino Acid Ionic Liquid Blends in CO₂ Absorption and Desorption

The utilization of carbonic anhydrases (CAs) for CO2 capture aligns with the principles of environmental sustainability. However, there is an urgent need to minimize the cost of CA purification while improving their performance in harsh environments. A novel strategy was proposed to solve the above problems by employing the ferritin-tagged CA variant (DvCA8.0-F). The purification is achieved by low-speed centrifugation, yielding 92% activity recovery and 95% purity. After 14 weeks of incubation in a 50% MDEA solution at 50 °C, DvCA8.0-F maintained activity nearly equivalent to the initial activity, which showed remarkable stability compared to the free ones. Encouragingly, DvCA8.0-F had a yield of up to 800 mg/L, allowing for cost-effective CA-assisted CO2 absorption and desorption in MDEA solutions. The results show that DvCA8.0-F reduced the absorption time from 70 to 50 min at 40 °C and desorption time from 40 to 25 min at 96 °C in 25%MDEA+1%[N1111][Gly] solution with a final CO2 load and a stripped amount of CO2 at the same time. DvCA8.0-F exhibits the maximum reaction rate at 96 °C; the CO2 regeneration efficiency improved from 60% at 87 °C to 72%. When the concentration of DvCA8.0-F was 1.5 g/L, the absorption rate of CO2 reached about 90% of that of the 25% MEA solution. These results demonstrate the simplicity of preparation and the outstanding properties of DvCA8.0-F, which paves a feasible way for CA-assisted CO2 capture. This exciting strategy may also have excellent potential in enzymes for innovative chemical synthesis to achieve the sustainable development of green chemistry.