Cellulose nanostructures from wood waste with low input consumption

Currently, cellulose nanostructures (CNS) are obtained using pretreatments of lignocellulosic residues. In this work, different conditions in the enzymatic isolation process were studied to obtain CNS, aiming an alternative eco-friendly method. Two isolation methodologies were used: a) one submitting the residue to an alkaline pretreatment and b) other using the lignocellulosic waste directly without pretreatment. A commercial complex of enzymes (Ctec (R)) was used, varying the time to which the substrate was exposed to the enzymes at 12, 24 and 48  h, searching for the better condition to CNS obtaining. The application of alkaline pretreatment removed 73% of hemicellulose and 50% of lignin from wood fiber leading to a more exposed cellulose structure and increased the amount of nanocellulose produced. The obtained nanostructures were needle-shaped of approximately 70  nm wide. However, CNS of similar size and shape were received as well without pretreatment application, allowing their obtainment with lower reagent consumption through a more environmentally efficient route, as presented in the life cycle impact assessment (LCIA) where energy consumption and acidification potential were considered. (C) 2018 Elsevier Ltd. All rights reserved.