Sustainable dyeing of poplar wood infected with Fusarium decemcellulare

Sustainable wood processing demands eco-friendly dyeing methods. Fungal bio-dyeing offers a promising alternative to synthetic dyes, but systematic research on wood dyeing using vibrant dye-producing fungi, especially red ones, is lacking. In this study, a red stain fungus, Fusarium decemcellulare, was cultivated in nitrogen-source-modified Czapek–Dox medium, after which sterilized poplar specimens were placed in the fungal culture for bio-dyeing. Key properties were systematically assessed: the chromatic values, physical-mechanical parameters, chemical composition, surface characteristics, and morphology. Results indicated that the bio-dyeing process induced significant chromatic alterations, manifesting as a 34.6±1.0 NBS colour difference (ΔE*) with coordinated hue shifts towards red (22.5±1.0 NBS a*), coupled with reflectance reduction. The infection minimally impacted structural integrity: mass loss and longitudinal compressive strength reduction were slight. The spectroscopic analyses (FTIR, XPS) confirmed a physical dye adsorption onto wood. Significant improvement of surface wettability (contact angle decreased from 100.5° to 65.4°) and an increase in surface roughness enhanced the potential for coating and adhesion. SEM confirmed dye deposition and mycelial interlocking within wood structures. Fusarium decemcellulare bio-dyeing provides an effective, sustainable route for poplar wood dyeing, producing vibrant colour while preserving key mechanical properties and improving surface functionality.