Covalent immobilization of xylanase from Thermomyces lanuginosus on aminated superparamagnetic graphene oxide nanocomposite

Abstract

Today, immobilization of enzymes has been extensively considered in a wide variety of applications in industries. Xylanase is a hemicellulotic enzyme with effective usages that has attracted the attention of researchers. In this work, xylanase from Thermomyces lanuginosus was covalently immobilized on modified graphene oxide nanosheets (NGO) via cyanuric chloride linker. The magnetic nanoparticles were perched on NGO to facilitate separation of nanocarrier from the reaction media. To decrease the steric hindrance and allow the high-molecular weight xylan as a substrate to approach the active site of the immobilized xylanase, polyethylene glycol bis-amine was used as a spacer. Various techniques such as TEM, SEM, FTIR, VSM and TGA were applied to characterize the structure of synthetic nanocomposite. The amount of immobilized xylanase was quantified by Bradford assay, and the immobilization efficiency was determined about 67%. The results showed that thermal stability, pH stability, reusability and storage stability were improved for immobilized enzyme and the kinetic parameters, $${K_m}$$ and $${v_{\hbox{max} }}$$ values, were increased, suggesting the great potential of the functionalized NGO as a novel nanocarrier in bio-industry applications.