This study investigated the potential of mycelium-based biocomposites as sustainable insulation materials by employing Ganoderma lucidum to transform agro-food residues, including wheat bran, rice straw, and spent coffee grounds into medium-density composites with tunable mechanical and thermal properties. The influence of substrate composition, fermentation conditions and fungal growth dynamics on the final material properties was systematically evaluated. Microstructural and compositional analyses were conducted to elucidate key factors for the mechanical performance and thermal behavior, providing insights for tailoring these materials.
Among the tested substrates, wheat bran-based biocomposites exhibited the highest mycelial colonization and superior mechanical performance, with compressive strengths reaching 43 kPa, comparable to that of expanded polystyrene (EPS), a conventional insulation material. Fire performance tests indicated moderate flame propagation, with reduced peak heat release rates relative to EPS. The fire performance index of the composites range from 0.06-0.15 m²s/kW depending on the lignocellulosic feedstock, surpassing or matching the value for EPS (0.08 m²s/kW). Water contact angle measurements (106-120°) confirmed the intrinsic surface hydrophobicity of the biocomposites, further supporting their suitability for insulation applications.
Beyond their functional performance, these biocomposites were produced with significant lower energy inputs compared to EPS, utilizing agri-food waste as a renewable feedstock. The findings demonstrate the feasibility of mycelium-derived composites as a bio-based alternative for thermal insulation, offering a circular and resource-efficient solution for sustainable building materials while valuable insights into their structure–property relationships.