Green and sustainable biomaterials: Edible bioplastic films from mushroom mycelium

Scalable mycelium biomaterials with excellent biodegradable and mechanical properties are attracting widespread attention. However, the inherent brittleness of biomass materials greatly limits their applications in reality, such as packaging and flexibility. In this work, three mycelium films were produced by the capacity of mycelium to spontaneously form three-dimensional biopolymer networks with a toughness of 127.32 kJ/m3 (Ganoderma lucidum), 71.95 kJ/m3 (Auricularia polytricha), and 87.52 kJ/m3 (Pleurotus ostreatus), respectively. After glycerol treatment, the toughness of the films increased by more than 440%, and these films' surfaces were made smooth and hydrophilic. It has been shown that the hydrogen bonding interactions between glycerol and polysaccharides as well as proteins in mycelium enhance the mechanical and hydration properties of mycelial films. The new strategy of using glycerol to improve the properties of mycelium films will advance on mycelium materials research.