Fungi to the rescue; the use of mycelium in the development of novel, sustainable bio-based materials

Filamentous fungi colonize organic materials such as plant waste by means of hyphae that grow at their tips and that branch subapically. As a result, a hyphal network is formed that is called mycelium with a fabric-like appearance. Here, material properties of the mycelium of the mushroom forming fungus Schizophyllum commune were determined in relation to environmental growth conditions and genetic background. Mycelium of liquid standing cultures of wild-type strain 4-39 grown in the light or dark at ambient or high CO₂ showed a Young’s modulus in the range of 438 - 913 MPa. The maximum tensile strength ranged between 5.1 – 9.6 MPa, while elongation at breaking ranged between 1.2 and 1.4 %. Mycelium of the hydrophobin deletion strain Δsc3 of S. commune showed a higher elongation at breaking (1.7 – 2.6 %). Moreover, it was stronger than wild-type with an elasticity modulus ranging between 1237 and 2727 MPa, and a maximum tensile strength of 15.6 – 40.4 MPa. Together, it is concluded that material properties of mycelium of S. commune can be modulated by changing the growth conditions and the genetic background. The resulting Young’s moduli and maximum strength is similar to specific thermoplastics showing the potential of fungal mycelium as a sustainable replacement of oil-based plastics.