Supercritical Fluid Immobilization of Horseradish Peroxidase on Mesoporous Carbon for Environmental Remediation

Immobilization of enzymes on solid supports is crucial in enzymatic reactions and catalysis as it allows reutilization of soluble enzymes and reduces cost. Covalent immobilization of horseradish peroxidise(HRP) on surface-modified mesoporous activated carbon (SMAC) in combination with supercritical carbon dioxide (scCO2) has been investigated in this study. HRP loading in the scCO2 environment was consistently higher for different HRP: SMAC ratios. The significant increase in the rate and quantity of HRP immobilization is attributed to the favourable transport properties of solutes in scCO2 coupled with greater affinity of HRP for the non-polar supercritical solvent which enhances the diffusivity of enzymes into the porous matrix. The immobilized HRP was successfully employed in removing phenol from water via polymerization of dissolved phenol in the presence of hydrogen peroxide (H2O2). The study shows the advantage of using a mesoporous substrate as the immobilization platform for enzymes in combination with scCO2 as the transport medium.