In the transition from a linear to a circular economy, fungal mycelium-based materials are an upcoming class of materials as a sustainable alternative to animal and petroleum-based materials [1]. In addition to being bio-based and biodegradable, fungal mycelium has the advantage of the ability to consume lignocellulosic biomass, e.g. from agricultural side-streams, forming fungal mycelium-based composites with low or even negative CO2 footprints. Commonly, fungal composites are processed by moulding [1]. In recent years, extrusion-based additive manufacturing (extrusion-based AM) has emerged as a promising alternative approach for design or engineering needs with fungal mycelium, as extrusion-based AM offers e.g. much higher design freedom in geometry and complexity [2,3]. However, it is still in its early stages of development.
Here we present an extrusion-based AM approach to print fungal mycelium-based composites based on two printing pastes from the fungus F. fomentarius with either inactive [5] or inoculated living fungal mycelia [4]. While inactive fungal mycelium worked as a fibre-reinforcing agent [5], living fungal mycelium provided additional properties due to its active growth. A suitable paste formula was proposed for the latter, which kept fungal vitality and promoted fungal growth after printing. Thus, lightweight composites with hydrophobic surface and printing accuracy down to millimetre level and printing heights up to 30 mm in complex shapes have been printed (Figure 1) [4]. By separating the fungal mycelium skin from the printed substrate after inactivation and drying, 3D fungal skins have been prepared, which will open new paths in fungal mycelium-based materials production.

 

 

References

[1] N. K. Sreerag et al. Polym. Rev., 2025, 65:1, 169–198.

[2] A. Mohseni et al. biomimetics, 2023, 8:2, 1–24.

[3] S. Gantenbein et al. Nat. Mater., 2023, 22, 128–134.

[4] H. Chen et al. Mater. Adv., 2025, 6, 5149–5158.

[5] H. Chen et al. Fungal Biol. Biotechnol., 2021, 8:21, 1–11.