The development of process engineering approaches to integrate the production of biofuels and high value-added biobased products, such as enzymes and nanocellulose, is crucial to improve the financial performance and sustainability of lignocellulosic biomass biorefineries. Here, the feasibility of applying enzymes produced on-site to obtain nanocellulose was evaluated using eucalyptus cellulose pulp as a model feedstock. A systematic analysis of the structural properties of the nanomaterials obtained after hydrolysis using a cellulolytic enzymatic complex with high endoglucanase specific activity (17.09 IU/mg protein ), produced by Aspergillus niger, followed by sonication, revealed that longer ball milling pretreatment and reaction times favored extraction of the cellulose nanocrystals (CNCs). The highest yield (24.6%) of CNCs was achieved using 96 h of enzymatic hydrolysis of the ball-milled cellulose pulp, followed by sonication for 5 min. The CNCs presented approximate lengths of 294.0 nm and diameters of 24.0 nm, and the crystallinity index increased from 57.5% to 78.3%, compared to the cellulose pulp that was only ball milled. These findings demonstrated that nanocelluloses could be successfully extracted using on-site produced enzymes and that the sustainable integrated process reported here could contribute to the development of the nascent biobased economy.

In this study, ginger residue from juice production was evaluated as a raw material resource for preparation of nanofiber hydrogels with multifunctional properties for advanced wound dressing applications. Alkali treatment was applied to adjust the chemical composition of ginger fibers followed by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation prior to nanofiber isolation. The effect of alkali treatment on hydrogel properties assembled through vacuum filtration without addition of any chemical cross-linker was evaluated. An outstanding absorption ability of 6200% combined with excellent mechanical properties, tensile strength of 2.1 ± 0.2 MPa, elastic modulus of 15.3 ± 0.3 MPa, and elongation at break of 25.1%, was achieved without alkali treatment. Furthermore, the absorption capacity was tunable by applying alkali treatment at different concentrations and by adjusting the hydrogel grammage. Cytocompatibility evaluation of the hydrogels showed no significant effect on human fibroblast proliferation in vitro. Ginger essential oil was used to functionalize the hydrogels by providing antimicrobial activity, furthering their potential as a multifunctional wound dressing.