Fungal Pigments for Staining of Forest Products Materials

The sustainable replacement of synthetic dyes with bio-based colorants is a key challenge for green material innovation. This case study builds on spalting – the fungal production of colored zones and contrasting structures in wood – and investigates fungal pigments (derived here from Aureobasidium pullulans) as a natural alternative for coloring wood products.
Pre-studies examined growth stimulation of A. pullulans through nutrient additives and wood impregnation to imitate natural blue-staining. Fungal pigments were obtained via submerged cultivation in nutrient-rich media. Pigment biomass was harvested, dried, and subjected to ultrasonic-assisted extraction and purification. Integration of pigments into wood fibers was achieved through dispersion, resulting in fiber panels with varying pigment loadings (3.5–14% dry weight). Analytical characterization included FT-IR spectroscopy for chemical profiling, CIELab color measurements, and UV-irradiation.
Nutrient supplementation enhanced A. pullulans biomass growth, highlighting the potential for using waste-derived industrial substrates in cultivation. Wood impregnation with A. pullulans increased UV stability of treated samples, demonstrating an additional protective effect. FT-IR analysis of ultrasound-extracted pigments revealed functional group differences, suggesting improved binding potential within wood fibers. Comparative analyses against non-pigmented reference boards showed distinct coloration in CIELab measurements, with intensity gradually increasing in proportion to pigment loading.
This work integrates fungal biotechnology with forest products materials, demonstrating technical feasibility and ecological relevance. By showing potential for waste-derived substrates utilization for cultivation and introducing bio-pigments into forest products materials, the study provides a pioneering pathway for bio-based coloration of construction and design materials. These findings highlight fungal pigments as a viable, safe, and sustainable alternative for material pigmentation, with potential applications in wood products and bio-based materials.