Surface functionalized natural inorganic nanorod for highly efficient cellulase immobilization

Abstract

An attapulgite@chitosan (ATP@CS) nanocomposite was prepared by coating chitosan onto naturally needle-like nanoscale attapulgite clay. The nanocomposite was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. Cellulase was covalently immobilized on this ATP@CS support using glutaraldehyde activation method and compared to (3-aminopropyl) triethoxysilane modified ATP (ATP–APTES) support. The amount of cellulase on the ATP@CS and ATP–APTES was 88.3 and 76.5 mg g⁻¹, respectively. The reusability and effects of pH and temperature on activity were studied. The ATP@CS immobilized cellulase exhibited higher pH and thermal stability as well as good reusability compared to the ATP–APTES immobilized cellulase and the free cellulase. The immobilized cellulase samples were also utilized to hydrolyze wheat straw to evaluate their potentially practical applications.