Although deep eutectic solvents (DESs) have demonstrated significant potential in lignin processing, their influence on molecular stacking and conformational evolution during lignin dissolution and nanoparticle formation remains insufficiently understood. Here, we develop a green, straightforward, and single‐step approach to produce self‐assembled lignin nanoparticles (LNPs). The LNPs obtained using the acidic DES method exhibited a great size reduction, with an average size approximately one‐ninth of that produced by conventional solvent‐exchange methods. To gain mechanistic insights into the reconstruction, dissolution, and self‐assembly of lignin in DESs, we integrate structural characterization with molecular dynamics simulations. Specifically, we simulate the dynamic behavior and configurational states of high‐molar‐mass lignin models (4,182 g mol ⁻¹ ) in aqueous solvent systems. The results reveal the critical role of molecular structure, intra/intermolecular π–π interactions, stacked conformations, solvent‐specific effects in determining the size and compactness of LNPs. Notably, the DES stabilizes lateral‐shifted configurations, promoting the formation of small and compact LNPs. In contrast, the tetrahydrofuran/H ₂ O solvent system favors offset‐stacked configurations and hydrophobic interactions, leading to larger, spherical LNPs. Overall, our findings offer new insights into the underlying mechanisms of LNP formation using DESs, demonstrating the possibility of regulating and controlling lignin assemblies through solvent parameters.

3D printing enables sustainable product innovations through novel design, reduced use of materials, and local manufacturing. Sustainable 3D printing can further be realized using recyclable materials. Cellulose is an abundantly available renewable material. Modified celluloses, such as thermoplastic cellulose esters, are widely used in injection molding applications. The aim of this research was to study the properties of a cellulose-based composite (cellulose acetate propionate (CAP) polymer matrix with 20 wt. % microcellulose) in injection molding and granular extrusion-based 3D printing processes over multiple recycles. The impact of the processing methods on the composite’s properties were investigated. Both injection molded and 3D printed samples were ground with plastic grinding mill to particle sizes below 3 mm after each preparation stage and reused as such in the next process cycle. Morphology, mechanical and thermal properties, and material degradation were analyzed. The thermoplastic cellulose-based compound was found to be directly recyclable for both processes without the need for any additional compounding steps. The polymer matrix was able to withstand at least seven processing cycles without degradation. However, microcellulose was found to be more sensitive to thermal stress. The mechanical and thermal properties of the cellulose-based composites remained close to initial levels throughout.

Lytic polysaccharide monooxygenases (EC1.14.99.53-56, LPMOs) are oxidative enzymes with the capability to enhance lignocellulose saccharification as well as nanofibrillation of cellulosic fibres. The parameters affecting the efficiency of oxidative modification of cotton linters and softwood kraft fibres by LPMO from Trichoderma reesei (Tr AA9A) were studied here. Circular dichroism experiments were carried out to analyze the thermal stability and to indicate the optimum temperature for the experiments. The enzyme was found to be most thermostable at pH 5 but can tolerate up to 40–50 °C at neutral pH. The enzymatic fibre oxidation efficiency was found to be dependent on reductant (gallic acid) and hydrogen peroxide supply in a pH dependent manner. A high resolution UHPLC-IM-MS method was used for identification of oxidized oligosaccharides released in the enzymatic treatments. A microscopy method was applied for analysis of single fibre dissolution kinetics of Tr AA9A pretreated softwood kraft fibres, demonstrating that the oxidative enzymatic treatment facilitated the fibre dissolution and degraded the fibre surface structures, which prevent swelling. Graphical Abstract