(621k) Crosslinked Chitosan Coating on Magnetic Mesoporous Silica with Pre-Adsorbed Enzymes


The approach of carbon conversion and utilization (CCU) is gathering a great attention because CCU utilizes CO2 to produce various chemicals and products. Especially, Carbonic anhydrase (CA) which can catalyze the conversion of CO2 to bicarbonate without external energy input, in mild reaction conditions is gathering a growing attention. However, it is a challenging task to develop a protocol of enzyme immobilization for the achievement of high loading and stability in order to improve the economy of biocatalytic conversion of CO2. In this work, we used magnetically-separable spherical mesocellular siliceous foam (Mag-S-MCF) for the immobilization and stabilization of carbonic anhydrase by using a protocol of crosslinked chitosan (CS) coating. CA was adsorbed into 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.