Effects of different amounts of cellulase on the microstructure and soluble substances of cotton stalk bark

Abstract

AbstractThere are plant cuticle and complex cell walls on the outer surface of cotton stalk bark (CSB), which reduce the efficiency of liquid penetration of CSB. To increase the permeability of liquids, these barriers need to be broken. Cellulase can selectively hydrolyze cellulose into glucose, and its action conditions are mild. Therefore, cellulase treatment is one of the excellent ways to break the CSB liquid permeation barrier. This experiment studied the effects of different amounts of cellulase treatment on the enzymatic hydrolysis products and surface of CSB. Scanning electron microscopy (SEM) and nano-CT were used to observe the changes in the microscopic morphology of CSB. Ion chromatography and an ultraviolet–visible spectrophotometer were used to determine the dissolution of CSB. The results showed that the cuticle of CSB treated with cellulase was broken, and the cell wall of phloem fibers became thinner, which increased the accessibility of liquid. The content of monosaccharide and lignin in CSB treatment solution increased with the increase of cellulase dosage. Correspondingly, the proportion of polysaccharides on the outer surface of CSB continued to decline and eventually stabilized. These experimental results can provide a reference for improving the permeability of natural fibers and the subsequent treatment effects of biomass products. Graphical abstract The pretreatment of cotton stalk barks with cellulase destroyed the dense protective structure of cell wall, and the content of monosaccharide and lignin in the treated solution increased with the increase of cellulase dosage.