Due to the natural cellulose encapsulated in both lignin and hemicellulose matrices, as well as in plant cell walls with a compact and complex hierarchy, extracting cellulose nanofibers (CNFs) from lignocellulosic biomass is challenging. In this study, a sustainable high yield strategy with respect to other CNF preparations was developed. The cellulose was liberated from plant cell walls and fibrillated to a 7–22 nm thickness in one bath treatment with H₃PO₄ and H₂O₂ under mild conditions. The cellulose underwent swelling, the lignin underwent oxidative degradation, and the hemicellulose and a small amount of cellulose underwent acid hydrolysis. The CNFs’ width was about 12 nm, with high yields (93% and 50% based on cellulose and biomass, respectively), and a 64% crystallinity and good thermal stability were obtained from bagasse. The current work suggests a strategy with simplicity, mild conditions, and cost-effectiveness, which means that this method can contribute to sustainable development for the preparation of CNFs.

The significant challenges in the use of cellulose as a replacement for plastic are its mechanical properties’ degradation and uncontrolled deformation during the rewetting process. Herein, inspired by the reinforcement of cellulose by lignin in natural plant tissue, a strong and water-stable lignin–cellulose composite (LCC) was developed. A nanocellulose hybrid lignin complex (CHLC) created from bagasse residue after enzymatic hydrolysis was added into a pulp of bleached fibre extracted from pine to produce a lignin–cellulose sheet. The lignin as a water-stable reinforcing matrix, via the hydrogen bonding of the nanocellulose in the CHLC with the fibre was efficiently introduced onto the fibres and the fibre network voids. Compared with a typical lignin-free cellulose sheet, the dry strength and wet strength of the LCC were 218% and 2233% higher, respectively. The developed LCC is an eco-friendly and biodegradable alternative to plastic.

To overcome the biological barriers formed by the lignin–carbohydrate complex for releasing fermentable sugars from cellulose by enzymolysis is both imperative and challenging. In this study, a strategy of intergranular swelling of cellulose combined with hydrolysis and oxidation was demonstrated. Pretreatment of the bagasse was evaluated by one bath treatment with phosphoric acid and hydrogen peroxide. The chemical composition, specific surface area (SSA), and pore size of bagasse before and after pretreatment were investigated, while the experiments on the adsorption equilibrium of cellulose to cellulase and reagent reuse were also performed. Scanning electron microscopy (SEM) and high-performance liquid chromatography (HPLC) were employed for microscopic morphology observations and glucose analysis, respectively. The results showed that pretreated bagasse was deconstructed into cellulose with a nanofibril network, most of the hemicellulose (~100%) and lignin (~98%) were removed, and the SSA and void were enlarged 11- and 5-fold, respectively. This simple, mild preprocessing method enhanced cellulose accessibility and reduced the biological barrier of the noncellulose component to improve the subsequent enzymolysis with a high glucose recovery (98.60%).