Bolaski et al. [155] patented the use of cellulase to improve cellulose fibrillation in the papermaking process.Since then, an extensive investigation has been carried out to find an economic way to apply this process [156,157]. Recently, the production of CNF with the usedof mild enzymatic hydrolysis was reported [127,158,159]. In these works, a monocomponent endoglucanase (Novozym 476 from Novozymes A/S, Denmark) was used. Some studies [160,161] reported the use of a cellulase solution (Celluclast from Novozym A/S, Denmark),which is a mixture of endoglucanase, exoglucanase, and cellobiase with the major activity of endoglucanase and exoglucanase. Nechyporchuk et al. [162] compared the production of CNF using the monocomponent endoglucanase and a mixture of endoglucanase, exoglucanase andcellobiase. They concluded that the monocomponentendoglucanase has a better effect on the nanofibril separationsince the reduction in PD is not very pronounced.