Mechanics of Biomineralized Mycelium Materials

Mycomaterials are composed of filamentous fungi that grow into crosslinked networks called mycelium. The mechanics of these materials have been demonstrated to be dependent on density, degree of crosslinks, and processing conditions, while there has been less work on understanding the impacts of extracellular polymeric substance (EPS) composition. Here, we leverage genetically engineered Aspergillus niger to express silicatein on the cell surface, which enables biomineralization. We measure the uniaxial stress-strain response of A. niger films and fibers with varying processing conditions and inorganic coating compositions. We observe that aligning the A. niger as fibers and the introduction of the inorganic coating increases the elastic modulus and yield stress of the material. Our results provide fundamental insights into how biomineralization and structural control from processing impacts the mechanical properties of mycomaterials.