Facile Cellulase Immobilisation on Bioinspired Silica

Abstract

Cellulases are enzymes with great potential for converting biomass to biofuels for sustainable energy. However, their commercial use is limited by their costs and low reusability. Therefore, the scientific and industrial sectors are focusing on finding better strategies to reuse enzymes and improve their performance. In this work, cellulase from Aspergillus niger was immobilised through in situ entrapment and adsorption on bio-inspired silica (BIS) supports. To the best of our knowledge, this green effect strategy has never been applied for cellulase into BIS. In situ entrapment was performed during support synthesis, applying a one-pot approach at mild conditions (room temperature, pH 7, and water solvent), while adsorption was performed after support formation. The loading efficiency was investigated on different immobilisation systems by Bradford assay and FTIR. Bovine serum albumin (BSA) was chosen as a control to optimize cellulase loading. The residual activity of cellulase was analysed by the dinitro salicylic acid (DNS) method. Activity of 90% was observed for the entrapped enzyme, while activity of ~55% was observed for the adsorbed enzyme. Moreover, the supported enzyme systems were recycled five times to evaluate their reuse potential. The thermal and pH stability tests suggested that both entrapment and adsorption strategies can increase enzyme activity. The results highlight that the entrapment in BIS is a potentially useful strategy to easily immobilise enzymes, while preserving their stability and recycle potential.

Effect of Deep Eutectic Solvents on the Activity and Stability of Cellulases and Pectinases

“…The enzyme activity of both enzymes was determined by the 3,5dinitrosalicylic acid (DNS) method 25 with minor modifications to the method.…”

Research Progress on Lignocellulosic Biomass Degradation Catalyzed by Enzymatic Nanomaterials

“…Because of the hydrophilicity of the surface and the existence of many hydroxyl groups, silica can immobilize biomolecules by adsorption, covalent bond, and even wrapping. Benedetti et al [80] . simply immobilized cellulase with silica, and the immobilized cellulase had high activity (90% activity, while adsorptive enzyme activity was about 55%) while maintaining its stability and recovery potential.…”

“…Because of the hydrophilicity of the surface and the existence of many hydroxyl groups, silica can immobilize biomolecules by adsorption, covalent bond, and even wrapping. Benedetti et al [80] simply immobilized cellulase with silica, and the immobilized cellulase had high activity (90% activity, while adsorptive enzyme activity was about 55%) while maintaining its stability and recovery potential. Califano et al [81] used tannic acid template mesoporous silica nanoparticles to immobilize β-glucosidase and proved that the immobilized enzyme retained most of the secondary structure of the enzyme and ensured the catalytic activity.…”

Cellulase Immobilization on Nanostructured Supports for Biomass Waste Processing

“…The major nanostructured supports utilized for cellulase immobilization include nanoporous materials (MOFs [ 80 ], biochars [ 81 , 82 , 83 ], porous silica [ 84 ], etc. ), nanohydrogels, polymer NPs, magnetic NPs, etc.…”