Immobilized cellulase on Fe3O4 nanoparticles as a magnetically recoverable biocatalyst for the decomposition of corncob

Abstract

A magnetically recoverable biocatalyst was successfully prepared through the immobilization of cellulase onto Fe3O4 nanoparticles. The magnetic nanoparticles were synthesized by a hydrothermal method in an aqueous system. The support (Fe3O4 nanoparticles) was modified with (3- aminopropyl)triethoxysilane, and glutaraldehyde was used as the cross-linker to immobilize the cellulose onto the modified support. Different factors that influence the activity of the immobilized enzyme were investigated. The experimental results indicated that the suitable immobilization temperature and pH are 40 °C and 6.0, respectively. The optimal glutaraldehyde concentration is ∼2.0 wt%, and the appropriate immobilization time is 4 h. Under these optimal conditions, the activity of the immobilized enzyme could be maintained at 99.1% of that of the free enzyme. Moreover, after 15 cyclic runs, the activity of the immobilized enzyme was maintained at ∼91.1%. The prepared biocatalyst was used to decompose corncobs, and the maximum decomposition rate achieved was 61.94%.