Reinforced chitosan beads by chitin nanofibers for the immobilization of β-glucosidase

Abstract

A chitosan (CS) solution was filled with partially deacetylated α-chitin nanofibers (DEChN) and the composite (DEChN/CS) beads prepared thereof were used for the immobilization of β-glucosidase. The filling of chitin nanofibers resulted in an increase of the shear modulus (G′, G′′), which indicated an improvement to the mechanical properties of the DEChN/CS composite beads. Meanwhile, the specific surface area was improved from 46.47 m² g⁻¹ to 229.71 m² g⁻¹ when the chitosan beads were filled with the chitin nanofibers, and the prepared DEChN/CS composite beads had a broad pore size ranging from 20 nm to 60 nm. Moreover, a more porous and fibrous structure in the SEM image of the DEChN/CS beads was observed compared to that of the sole CS beads. The chitin nanofibers provided a fibrous network in the chitosan matrix that enhanced both the mechanical and porous properties of the DEChN/CS composite beads, which is normally considered contradictory. All of these enhanced features improved the efficiency of enzyme immobilization from 40% in the chitosan (CS) beads to 67% in the DEChN/CS composite beads.