Potential of Using the Mycelium of Pleurotus Ostreatus as a Thermal Insulator

The construction industry is one of the largest generators of waste. The majority of widely used insulation panels are made of synthetic materials that end up in landfill. The mycelium of the mushroom Pleurotus ostreatus, 100% compostable, has interesting properties that give it the potential to be the next trendy bio-based material. The literature reports its low thermal conductivity comparable to that of currently used insulation materials. The fire resistance of mycelium is also better than that of extruded polystyrene insulation materials. Mycelium has a lower heat production rate, it generates less smoke and CO₂ in addition to having a longer ignition time (300 vs. 50 s) limiting the spread of fires. Mycelium also has interesting acoustic properties. However, there is still much to do with the technology of growing and transforming mycelium into construction materials to be developed in Canada. The overall objective of this study is to produce an insulator that can be 100% composted after use. The specific objectives are to define the mycelium culture protocol, to define the optimal growth temperature of Pleurotus ostreatus on ash chips, and to measure the thermal conductivity by the modified transient plane source method (MTPS) in order to compare them to those measured for hemp and glass wool. Different combinations of mushroom species and substrates can be used to manufacture mycelium-based products like that of Pleurotus ostreatus which is an edible mushroom safe for human health. The final properties of the material obtained will depend on the chosen mycelium-substrate composition. Pleurotus ostreatus grows on ash chips free of insecticide. The different experimental tests allow us to define the optimal substrate composition (10% rye; 90% ash) for an optimized growth time at the best incubation temperature (25, 30, 35 °C) determined by isothermal calorimetry tests with ash as the reference substrate. Preliminary tests allow us to consider the use of mycelium as a thermal insulator following more in-depth studies.