Chemical and Physical Insights of Efficient Conversion of Lignin-Rich Camellia oleifera Shell to Thermal and Fire Resistant Mycelium-Based Composite

Mycelium-based composite (MBC) shows great potential for replacing petroleum-based plastic products in various engineering applications, but its inefficient biomanufacturing has long been a significant challenge for upscale production and industrialization. This paper presents a novel and efficient preparation of MBC from the ingenious mixture of lignin-rich Camellia oleifera Abel. shell (COS) and the lignin-first fungus Ganoderma sessile ( G. sessile ). The preparation process has been reduced from 2–6 weeks to 8 days by combining liquid and solid-state fermentations. The chemical and physical pathways of COS and mycelium during solid-state fermentation were specifically explored to elucidate the transformation mechanism of the composite. The adhesive-free, layered, porous structure with different particle sizes of COS provided the developed MBC with a superb compressive strength of up to 0.73 MPa and a low thermal conductivity of up to 0.041 (±0.001) W m –1 K –1 . The protein-rich mycelium network within and on the surface grants the developed MBC (peak heat release rate of 121.7 kW m –2 ) with superior fire resistance over the widely used expanded polystyrene (peak heat release rate of 177.3 kW m –2 ). This work not only offers an effective solution of valorizing COS agroforestry waste but also establishes an efficient, feasible process of MBC manufacturing.