Crosslinked chitosan coating on magnetic mesoporous silica with pre-adsorbed carbonic anhydrase for carbon dioxide conversion

•A new protocol of crosslinked chitosan coating onto mesoporous material with pre-adsorbed enzymes.•Immobilized and stabilized carbonic anhydrase for CO2 conversion and utilization.•Magnetic separation of enzyme immobilizations for their facile recovery and recycled uses.

Carbonic anhydrase (CA), an enzyme converting CO2 to bicarbonate, was adsorbed into magnetically-separable spherical mesocellular siliceous foam (Mag-S-MCF). Then, chitosan was adsorbed onto the surface of Mag-S-MCF with pre-adsorbed enzymes, and further crosslinked via the glutaraldehyde treatment. The resulting composite materials, the crosslinked chitosan coating on Mag-S-MCF with pre-adsorbed CA (ADS-CA/CS-GA), could effectively prevent leaching of enzymes, showing no decrease of enzyme activity under shaking (200 rpm) for 85 days. ADS-CA/CS-GA also showed no activity decrease under recycled uses via facile magnetic separation, and could be successfully used for the biocatalytic CO2 conversion to bicarbonate, which was further utilized to generate calcium carbonate in the second batch reactor.

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