New nanostructured carriers for cellulase immobilization

Objectives. Cellulase is a multienzyme complex that breaks down cellulose contained in plant cell walls. Cellulase consists of three types of enzymes: endoglucanase, exoglucanase, and β-glucosidase, each of which is involved in the destruction of certain chemical bonds in cellulose. Nanobiocatalysts based on cellulase immobilized on nanostructured carriers are used for catalytic hydrolysis of biomass waste, as well as in the food industry and for environmental protection. This article reviews scientific developments in the immobilization of cellulase on nanostructured carriers. Methods. The article analyzes scientific papers published over the past five years that concerned the main aspects of immobilization of cellulase, an enzyme for processing cellulose biomass waste, on nanostructured carriers. The article examines methods of cellulase immobilization, the morphology of nanostructured carriers, and the factors affecting the enzyme activity and allowing one to achieve maximum conversion of cellulose-containing waste of plant origin. Results. Nanostructured carriers have a large surface area, providing high immobilization efficiency, and also create a favorable environment for activating cellulase and increasing its stability. This allows one to create nanobiocatalysts for efficient conversion of cellulose substrate. The conducted analysis of the latest trends shows that positive changes have occurred in immobilization methods and carrier compositions over the past five years. The article describes such nanostructured carriers as graphene layers, polymer nanoparticles, nanohydrogels, nanofibers, silica nanoparticles, hierarchical porous materials, and magnetic nanoparticles. Conclusions. Magnetically separable carriers increase the reliability of the biocatalyst and facilitate biocatalytic processes. The use of magnetic nanoparticles is especially advantageous due to their easy separation and the possibility of extracting the nanobiocatalyst for reuse.