The TEM image of the nanofiber suspension subjected to ET evidenced less pure nanofibers and bundles as compared with the suspension obtained by cr. On the basis of the study by Pelissari et al. (2014), incomplete hemicelluloses and lignin removal during treatment and interfibrillar hydrogen bonds formation accounted for the residual nanofiber bundles. ET did not remove these amorphous components as effectively as cr, which generated a barrier of cementing materials around the fiber bundles and hindered enzyme penetration into the cellulose chains. Consequently, impurities and bundles existed in the CNFs isolated by ET. Treatment with xylanase partially removed hemicelluloses. This happened because this enzyme usually removes the xylan fraction, since it has specific action and works mainly to degrade hemicelluloses to soluble oligosaccharides (Hassan et al., 2010).