3D-Printed Mycelium Biocomposites: Method for 3D Printing and Growing Fungi-Based Composites.

Despite recent advances in 3D printing and additive manufacturing, the main materials in rapid prototyping are derived from finite resources such as petroleum-based plastics. Researchers are developing alternatives to exhaustible and potentially environmentally harmful materials through biomaterials. Mycelium biocomposites are one promising area of inquiry; when mycelium decomposes biomass, it produces a composite biomaterial, which is fully compostable and has beneficial structural and hydrophobic properties. However, mold-based fabrication methods for biocomposites require tooling and limit the possible shapes. We introduce a novel method for directly 3D printing mycelium biocomposites without the need for molds or tooling. Our method comprises three main contributions: Mycofluid, a mycelium-inoculated paste that uses spent coffee grounds, a recycled biomass; Fungibot, a custom hardware system for 3D printing biopastes like Mycofluid; and a method for incubating mycelial growth within fresh 3D prints resulting in mycelium biocomposite parts. We illustrate our contributions through a series of objects showcasing our method and the material qualities of the parts. Notably, we demonstrate how living mycelium can fuse separate prints, enabling complex geometries that are otherwise challenging to 3D print as one part.