Enzymatic Extraction and Characterization of Nanocellulose from Cornhusk Fiber

Abstract Cornhusk is a renewable and abundant crop by-product whose diverse applications must be studied more extensively. However, thus far, cornhusk, as a raw material, has not been employed for production of cornhusk fiber (CF) nanocellulose (CNC). 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 CNC were as follows: cellulase concentration of 1 mg/g, pH of 4.8, temperature of 50 ℃, 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.