Enzymatic extraction and characterization of nanocellulose from cornhusk fiber

Poor disposal of crop wastes, such as incineration, will cause serious environmental problems. Using green methods to extract nanocellulose from cornhusk fiber (CF) can realize resource utilization of cornhusk, reduce environmental pressure and create market value. This study aims to extract and characterize nanocellulose using CF as a raw material by high-shear-assisted enzyme hydrolysis. The extraction process was optimized by investigating the particle size distribution. The optimal extraction conditions of cornhusk nanocellulose (CNC) were as follows: cellulase concentration of 1 mg/g, pH of 4.8, temperature of 50 degrees C, and 24 h treatment under high-shear conditions for 20 min. The morphological characteristics of the CNC and CF were investigated, and FTIR, XRD, and TGA analyses were performed. Compared with CF, CNC exhibited slenderer nanofibrils with a smoother surface. FTIR analysis showed that the peaks that represented hemicellulose, lignin, and pectin disappeared or diminished in the CNC spectrum. The crystal type of CNC did not change and was identical to that of CF (cellulose type I). The TGA results showed that CNC possessed a lower thermal stability and higher char residuals than those of CF.Graphical abstractExtraction process of nanocellulose from cornhusk fiber