An efficient nano-biocatalyst for lignocellulosic biomass hydrolysis: Xylanase immobilization on organically modified biogenic mesoporous silica nanoparticles

A biogenic mesoporous silica nanoparticles (MSNs)-based nanocarrier has been used for improving the stability and recyclability of PersiXyn2 as a recombinant xylanase enzyme. The biogenic MSNs (called RKIT-6 henceforth) were synthesized via a soft templating method using rice husk biomass as a renewable silica source. Then bis-(2-aminoethyl) ether modified RKIT-6 (denoted as bis-AE@RKIT-6) was prepared through the furnishing surface with bis-(2-aminoethyl) ether, as a pendant anchoring agent to immobilize PersiXyn2. The nanomaterials were characterized using nitrogen adsorption-desorption isotherms, atomic force microscopy (AFM), X-ray diffraction (XRD), molecular docking (MD) study, and thermogravimetric analysis (TGA). After immobilizing, PersiXyn2@bis-AE@RKIT-6, the optimal temperature of enzyme performance was improved more than 10 °C in comparison with the free enzyme. Such a way that PersiXyn2@bis-AE@RKIT-6 sample could maintain 90% of its maximum activity at the range of 30-60 °C. PersiXyn2@bis-AE@RKIT-6 also enhanced the degradation of lignocellulosic agro-waste (rice straw) and reducing sugar production up to 35% in comparison to the free enzyme. Moreover, PersiXyn2@bis-AE@RKIT-6 could be recycled for ninth runs with a reasonable decrease in its activity. This study presents an efficient nano-biocatalyst which in a more comprehensive sense can be considered as a promising candidate in the fields of animal feed and lignocellulosic biomasses saccharification.