Reactive Green 5-Decorated Polyacrylamide/Chitosan Cryogel: An Affinity Matrix for Catalase

Acrylamide/chitosan-based cryogel was fabricated, and a triazine dye, Reactive Green 5, was attached to the cryogel by nucleophilic substitution to build a dye affinity support for adsorption of catalase enzyme. Characterization of cryogel was performed using FTIR, SEM, EDX, BET, and swelling test. Synthesized cryogel beared pores with ~ 200 μm in size and the surface area of 11.8 m²/g. Maximum catalase adsorption was (17.6 ± 0.29 mg/g) measured at pH 4.0 and 25 °C. The adsorption sites on the cryogel were saturated at 0.75 mg/mL enzyme concentration. Increased ionic strength caused a decrease in adsorption capacity. Desorption of catalase from cryogel was enabled using 0.5 M NaSCN solution. Consecutive adsorption experiments were carried out fifteen times to evaluate the reusability of the cryogel. Thermal, storage, and operational stabilities of immobilized catalase were higher than the free one. The data produced implicate that catalase-adsorbed dye-affinity cryogel may be used for H₂O₂ detection or removal when necessary. Graphical Abstract.