Immobilization and Characterization of a Processive Endoglucanase EG5C-1 from Bacillus subtilis on Melamine–Glutaraldehyde Dendrimer-Functionalized Magnetic Nanoparticles

Abstract

Exploring an appropriate immobilization approach to enhance catalytic activity and reusability of cellulase is of great importance to reduce the price of enzymes and promote the industrialization of cellulose-derived biochemicals. In this study, Fe3O4 magnetic nanoparticles (MNPs) were functionalized with meso-2,3-dimercaptosuccinic acid to introduce carboxyl groups on the surface (DMNPs). Then, melamine–glutaraldehyde dendrimer-like polymers were grafted on DMNPs to increase protein binding sites for the immobilization of processive endoglucanase EG5C-1. Moreover, this dendrimer-like structure was beneficial to protect the conformation of EG5C-1 and facilitate the interaction between substrate and active center. The loading capacity of the functionalized copolymers (MG-DMNPs) for EG5C-1 was about 195 mg/g, where more than 90% of the activity was recovered. Immobilized EG5C-1 exhibited improved thermal stability and increased tolerability over a broad pH range compared with the free one. Additionally, MG-DMNP/EG5C-1 biocomposite maintained approximately 80% of its initial hydrolysis productivity after five cycles of usage using filter paper as the substrate. Our results provided a promising approach for the functionalization of MNPs, enabling the immobilization of cellulases with a high loading capacity and excellent activity recovery.

Sustainable Synthesis of Novel Green-Based Nanoparticles for Therapeutic Interventions and Environmental Remediation

“…Moreover, recently, the fabrication of polyindole multiwalled carbon nanotubes (MWCNTs) using biosynthesized ZnONPs was done for glucose oxidase immobilization and this novel nano catalyst can therefore be considered as an ideal candidate for the development of enzymatic biofuel cells . Similarly, Bacillus subtilis derived endoglucanase enzyme was used for the functionalization of dendrimer based magnetic NPs, and the designed nanocatalyst exhibited improved activity recovery and loading capacity . Recently, the surface modification of silver or tungsten (Ag/W) doped ZnONPs with CTAB was done to enhance its photocatalytic performance .…”