An antifouling epoxy coated metal surface containing silica-immobilized carbonic anhydrase supraparticles for CO₂...

Carbonic anhydrase (CA) has a promising application as a green and efficient biocatalyst for CO₂ capture, and many successful cases of immobilizing CA have been reported. However, CA antifouling coatings on metal for CO₂ sequestration have rarely been reported. Herein, dimeric CA from Sulfurihydrogenibium azorense (SazCA) with a ferritin tag, which was prepared by low-speed centrifugation with high yield, was adopted as a free enzyme and encapsulated in the sol-gel silica. The silica-immobilized CAs were dispersed into the commercialized metal-antifouling epoxy resin paint to obtain CA coated nickel foams, which had excellent stability, with 90 % and 67 % residual activity after 28 days of incubation at 30 °C and 60 °C, respectively. The CA coated nickel foams remained 60 % original activity after 6 cycles of use within 28 days. Then, a CA-microalgae carbon capture device was constructed using the CA coated nickel foams and Chlorella. The growth rate of Chlorella was significantly increased and the biomass of Chlorella increased by 29 % compared with control after 7 days of incubation. Due to the simple and cost-effective preparation process, sustainable and efficient CO₂ absorption, this easy-to-scale up CA coated nickel foam has great potential in CA assisted microalgae-based CO₂ capture and carbon neutrality.