Tailoring the Mechanical Properties of Fungal Mycelium Mats with Material Extrusion Additive Manufacturing of PHBH and PLA Biopolymers.

To advance the concept of a circular economy, fungal mycelium-based materials are drawing increased attention as substitutes for nonsustainable materials, such as petroleum-based and animal-derived products, due to their biodegradability, low carbon footprint, and cruelty-free nature. Addressing the challenge of mechanical properties in fungal mycelium products, this study presents a straightforward approach for reinforcing fungal mycelium mats. This is achieved by using two bio-based and biodegradable polymers, poly(3-hydroxybutyrate--3-hydroxyhexanoate) (PHBH) and polylactic acid (PLA), via material extrusion additive manufacturing (MEX AM), commonly known as 3D printing, to produce fungal mycelium-biopolymer composites. By analyzing the mechanical properties, roughness, and morphology, this study demonstrates significant improvements in ultimate tensile strength with the application of PHBH and even more with PLA, while elasticity is reduced. The study also discusses potential improvements to enhance the quality of the fungal mycelium-biopolymer composites without trading off bio-based and biodegradable features, offering a promising pathway for the development of more durable and sustainable fungal mycelium products.