Physical-Mechanical and Thermodynamic Properties of Mycelium-Based Biocomposites: A Review

Reducing the use of non-renewable resources is a key strategy of Circular Economy. Mycelium-based foams and sandwich composites are an emerging category of biocomposites relying on the valorization of lignocellulosic wastes and the natural growth of the living fungal organism. While growing, the fungus cements the substrate, that is partially replaced by the tenacious biomass of the fungus itself. The final product can be shaped to produce insulating panels, packaging materials, bricks or new-design objects. Only a few pioneer companies in the world detain a significant know-how as well as the possibility to provide the material characterization. Moreover, several technical details are not revealed due to industrial secrecy. According to the available literature, mycelium-based biocomposites show low density, good insulation properties both as it regards acoustic and thermal aspects. Mechanical properties are apparently inferior in comparison to EPS (expanded polystyrene), that is the major synthetic competitor. Nevertheless, mycelium-based composites can display an enormous variability on the basis of: fungal species and strain; substrate composition and structure; incubation conditions. Aim of the present review is to critically synthetize the available knowledge about the physical, mechanical and thermodynamic characterization of mycelium-based biocomposites with regard to the actual and potential applications.