An Oxidative Enzyme Boosting Mechanical and Optical Performance of Densified Wood Films

Nature has evolved elegant ways to alter the wood cell wall structure through carbohydrate-active enzymes, offering environmentally friendly solutions to tailor the microstructure of wood for high-performance materials. In this work, the cell wall structure of delignified wood is modified under mild reaction conditions using an oxidative enzyme, lytic polysaccharide monooxygenase (LPMO). LPMO oxidation results in nanofibrillation of cellulose microfibril bundles inside the wood cell wall, allowing densification of delignified wood under ambient conditions and low pressure into transparent anisotropic films. The enzymatic nanofibrillation facilitates microfibril fusion and enhances the adhesion between the adjacent wood fiber cells during densification process, thereby significantly improving the mechanical performance of the films in both longitudinal and transverse directions. These results improve the understanding of LPMO-induced microstructural changes in wood and offer an environmentally friendly alternative for harsh chemical treatments and energy-intensive densification processes thus representing a significant advance in sustainable production of high-performance wood-derived materials.

Automated summary

Nature has developed enzymes that can alter the wood cell wall structure, providing eco-friendly ways to customize the microstructure of wood for high-performance materials. In this study, an oxidative enzyme called lytic polysaccharide monooxygenase (LPMO) was used to modify the cell wall structure of delignified wood under mild reaction conditions. The enzymatic oxidation led to nanofibrillation of cellulose microfibril bundles, allowing the delignified wood to be densified into transparent anisotropic films under ambient conditions and low pressure. The enzymatic nanofibrillation promoted microfibril fusion and improved the adhesion between neighboring wood fiber cells, resulting in enhanced mechanical performance of the films in both longitudinal and transverse directions. This research advances our understanding of LPMO-induced microstructural changes in wood and provides an environmentally friendly alternative to harsh chemical treatments and energy-intensive densification processes, thus contributing to sustainable production of high-performance wood-derived materials.