Bioengineered upcycling of biomass waste into moldable, strong and flame-retardant structural materials

Developing moldable, strong, and fire-retardant structural materials from eco-friendly resources is crucial for addressing environmental challenges associated with petroleum-based polymers. In this work, we present an efficient approach to upcycling biomass waste into high-performance structural materials through fungal engineering and biomimetic mineralization. Woody waste, an abundant and renewable resource, is processed into biomass particles, was bounded together by fungal mycelium, providing excellent moldability and structural integrity. Furthermore, the incorporation of biomimetic mineralization enhances the mechanical properties (compressive strength: ≈5.37 MPa at 80 % strain) and flame retardancy of the materials. The fabricated mineralized mycelium wood (MMW) exhibits outstanding three-dimensional formability, low-density (≈0.175 g/cm³) and biodegradability. Lignocellulose naturally decomposes into nutrients through microbial catabolism, while CaCO₃ reenters the geological cycle, ensuring an environmentally friendly closed-loop system. Additionally, the end-of-life MMW can be mechanically disintegrated and reused, promoting circular economy principles. The wholly plant-derived and sustainable material concept offers an environmentally preferable option to replace synthetic petroleum-based materials, contributing to the advancement of eco-friendly structural materials with significant environmental and industrial implications. A novel approach for upcycling woody waste into structural materials. The materials exhibit excellent mechanical properties and flame retardancy. Outstanding moldability and biodegradability characterize the materials. With excellent recyclability, the materials support a circular economy.