Green magnetic hydrogels synthesis, characterization and flavourzyme immobilization based on chitin from Hericium erinaceus residue and polyvinyl alcohol.

In this study, a novel magnetic sensitive hydrogel was prepared based on fungal chitin extracted from Hericium erinaceus residue and polyvinyl alcohol (PVA) through a green and facile procedure of repeated freezing-thaw and in situ decoration of FeO. The prepared hydrogels were characterized and applied for flavourzyme immobilization. The results showed that magnetic FeO was successfully introduced into chitin/PVA matrix due to the porous networks of the hydrogels, and the prepared hydrogels displayed superparamagnetic behavior and improved gel strength due to the presence of FeO. The efficiency for flavourzyme immobilization was influenced by the mass ratios of chitin/PVA. The optimal flavourzyme immobilization carrier was obtained at 1:2 ratio of chitin/PVA. Compared with free flavourzyme, the hydrogels-embedded-flavourzyme (HEF) showed uniform optimal reaction temperature (50 °C), but slightly shifted pH value at 6.0. More importantly, HEF displayed preferable thermal stability and great reusability. This work provided a relatively simple, facile, low-cost and eco-friendly way to fabricate magnetic hydrogels, and the prepared hydrogels could be served as the promising material for enzyme immobilization application.