Viscosity control and reactivity improvements of cellulose fibers by cellulase treatment

Cellulase treatment for decreasing viscosity of cellulose (dissolving pulp) is a promising approach to reduce the use of toxic chemicals, such as hypochlorite in the dissolving pulp manufacturing process. In this study, the use of an endoglucanase-rich cellulase to replace the hypochlorite for this purpose and its improvements of the Fock reactivity were investigated. The results showed that at a given viscosity level, the replacement of hypochlorite treatment with a cellulase treatment in the bleach plant under otherwise the same conditions led to a higher Fock reactivity (72.0 vs 46.7 %). These results were due to the enzymatic peeling/etching mechanism, which partially peeled the primary wall of the fibers, thus improving the accessibility of fibers. The improved accessibility of the enzymatic treated pulp was supported by the positive fiber morphological changes determined, based on the SEM, BET and WRV methods. The alkali solubility results further supported the conclusion.