Immobilization of xylanase enzyme on poly-(HEMA-co-GMA) cryogel

Abstract

In this study, a polyethyleneimine (PEI) coated poly-(HEMA-co-GMA), hybrid cryogel column (HCC), was designed. HCC was synthesized via polymerization of gel-former factors at minus temperatures. The characterization experiments of the HCC were conducted through SEM, and FTIR experiments. At the end of the experimental periods, there was no significant decrease in the performance of the HCC. Then the HCC was used as a novel support for xylanase immobilization for the first time. the successful immobilization of xylanase was confirmed by FT-IR, while the biochemical properties and stability of the PHG/PI-Xyl were evaluated in terms of optimum pH, optimum temperature, thermostability, storage stability, reusability, and kinetic parameters, The optimum activities for both free and immobilized enzyme were recorded at pH 6.0, while optimum temperature for free was 55 °C and for PHG/PI-Xyl 60 °C. The PHG/PI-Xyl displayed remarkable thermal stability for 180 min at 60 °C, with 53.55%, and for free Xyl 32.05%. Meanwhile, it retained up to 49% and 69 % for free and immobilized xylanase of original activities after 4 weeks of storage at room temperature. The PHG/PI-Xyl retained about 58% of its original activity after 10 consecutive reuses, while Km for the free Xyl and PHG/PI-Xyl were calculated at 4.05 mg/mL and 2.62 mg/mL, whereas Vmax133.33 U/mL and 188.68 U/mL, respectively. As envisioned, this study suggests a promising way to solve the problems of high price and poor operational stability of the enzyme during biocatalytic.