(362f) Carbon Dioxide Conversion and Utilization Based on Highly-Stabilized Carbonic Anhydrase
Enzymes have attracted attention rapidly due to their promising applications such as biosensors, biofuel cells, proteomics, enzyme-linked immunosorbent assay (ELISA), antifouling and carbon dioxide conversion. In this work, we developed a enzymatic process for one-pot carbon dioxide (CO2) conversion and utilization based on conversion of CO2 to bicarbonate at ambient temperature with no energy input, by using carbonic anhydrase and carboxylated polyaniline nanofibers (cPANFs). Carbonic anhydrase was immobilized on cPANFs via the approach of magnetically-separable enzyme precipitate coatings (Mag-EPC), which is made of covalent enzyme attachment, enzyme precipitation and crosslinking with amine-functionalized magnetic nanoparticles. Mag-EPC showed a half-life of 236 days under shaking (200 rpm), even resistance to 70% ethanol sterilization, and recyclability via facile magnetic separation. For enzymatic one-pot CO2 conversion and utilization, Mag-EPC was used to accelerate the growth of microalga by supplying bicarbonate from CO2, representing 1.8-fold increase of cell concentration when compared to the control sample. After two repeated uses via magnetic separation, the cell concentration with Mag-EPC was maintained as high as the first cycle of microalgae cultivation. This one-pot CO2 conversion and utilization can be an alternative as well as complementary process to adsorption-based CO2 capture and storage as an environmentally-friendly approach, demanding no energy input based on the stabilized enzyme system.