Guaiacol-enhanced laccase secretion by Trametes versicolor for lignin modification toward high-performance bamboo composites

Abstract

Highlights: • Guaiacol-induced metabolic targeting enables precise lignin modification. • Selective lignin removal increases bamboo crystallinity. • β-O-4 cleavage raises phenolic hydroxyls, improving interfacial bonding. • Improved bamboo properties yield high-performance biocomposites.Data availability: Data will be made available on request.This study reports high-performance bamboo-based composites engineered through a biological eco-modification strategy involving targeted lignin depolymerisation. By leveraging guaiacol-enhanced Trametes versicolor pretreatment, we achieved substantial improvements in the mechanical properties and water resistance of bamboo-phenolic resin composites via efficient biological modification of Dendrocalamus sinicus. This targeted biological modification boosted laccase activity to 2566.28 U/L, selectively depolymerised lignin and hemicellulose (by 6.97% and 11.46%, respectively) while preserving the cell wall skeleton, increased the crystallinity of bamboo from 28.28% to 31.94%, and enhanced the surface reactivity of bamboo for subsequent resin bonding. This bioconversion enhanced bamboo's chemical reactivity via targeted lignin demethoxylation and β-O-4 bond cleavage, efficiently generating additional phenolic hydroxyl groups, while also improving surface wettability (contact angle reduced from 109.73° to 79.96°) to facilitate resin penetration. Consequently, the resulting composites exhibited superior fiber-resin interfacial bonding, leading to exceptional mechanical performance, with tensile strength reaching 286.65 MPa (40.2% higher than untreated controls) and bonding strength of 9.74 MPa (33.6% improvement). Furthermore, the composites demonstrated enhanced water resistance and interfacial stability, underscoring their suitability for load-bearing applications. This targeted lignin depolymerisation strategy directly optimises the bamboo-resin interface, offering a sustainable pathway for the industrial production of high-strength biocomposites and enabling the value-added utilisation of bamboo resources.The authors are grateful for the financial support from the Regional Project of the National Natural Science Foundation of China (32260362), the Joint Project of Yunnan Agricultural Basic Research (202401BD070001–025), the Foreign Experts Project of Yunnan Province (202505AO120007), the Reserve Talent Project for Young and Middle-aged Academic and Technical Leaders of Yunnan Province (202405AC350033), and the 111 Project (D21027)