Preparation of 3D porous cellulose‐chitosan hybrid gel macrospheres by alkaline urea system for enzyme immobilization

Abstract In order to find a low‐cost, green and sustainable immobilized enzyme carrier, cellulose material has been widely used in the field of immobilized enzyme, but the low specific surface area and apparent porosity limit its further application. In this article, cellulose and chitosan are dissolved in alkaline urea system through freeze–thaw cycle, then regenerate in weakly alkaline by sol–gel method and solvent exchange. A novel 3D porous cellulose‐chitosan hybrid gel macrospheres (CCMs) with high specific surface area (235.4–325.3 m 2 /g) are obtained after lyophilization. The cellulose‐chitosan macrospheres are characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X‐ray diffractive analysis (XRD) and the size, surface, and internal morphology of CCMs are observed by scanning electron microscopy (SEM). Furthermore, it is found that α‐amylase (AMY) could be successfully immobilized on the hybrid gel microspheres by glutaraldehyde regent. Compared with free α‐amylases, immobilized enzymes exhibit higher thermal stability, more broadly pH adaptive, and improved storage stability. After 10 cycles, the immobilized enzymes retain 77.5% of their initial activity.