Mechanical and acoustical properties of mycelium-based composites from spent mushroom substrates

Edible mushroom cultivation generates a large quantity of agricultural by-products that are often underutilized, leading to environmental and financial problems. This waste, known as spent mushroom substrate (SMS), consists of exhausted lignocellulosic materials and residual mycelium, the vegetative network of the fungus. This research explores the potential of repurposing SMS through different methods for producing mycelium-based composites (MBCs). MBCs have gained significant academic and commercial interest due to their unique capacity to upcycle agricultural and industrial waste into low-cost, environmentally sustainable composite materials. To evaluate the feasibility of using SMS for MBCs production, twelve distinct growing Treatments were compared. Treatments achieving over 50% surface colonization were selected for further evaluation of their mechanical and acoustic properties. Among these, Treatment 11 demonstrated the best overall performance, combining the highest mechanical strength with superior acoustic absorption. Mechanical testing revealed that SMS-based MBCs can reach a peak compressive stress of nearly 10 MPa and a Young’s Modulus of 45 MPa. Acoustic testing showed that the best-performing formulations achieved absorption coefficients (α) above 0.9 at 1600 Hz and maintained values exceeding 0.75 across most high-frequency bands (2400–6400 Hz), indicating strong potential for sound insulation applications. These findings highlight the potential for integrating agricultural waste management with innovative materials science to promote resource efficiency, reduce waste, and support sustainable practices. The study presents a compelling model of industrial symbiosis, bridging the agricultural and construction sectors and supporting future research on scalable bio-fabricated materials for sustainable building systems.