This Small Business Innovation Research Phase I project seeks to address the steadily growing but unsustainable polymer matrix composite (PMC) market. PMCs are leveraged for their high strength-to-weight and stiffness-to-weight ratios as compared to conventional engineering materials, but are notoriously unsustainable, energy-intensive to manufacture, and non-recyclable. Researchers have investigated encapsulating natural fibers with both petroleum-based polymers and biopolymers (e.g. cellulosic plastic) to produce more biocompatible composites with varying degrees of experimental and commercial success, but all attempts have still fallen short of an ideal "bio-composite". In this project, we will create and characterize an entirely new bio-composite material. The basic idea is to use mycelium as a matrix for binding natural fibers and core filler materials together in sustainable composite parts. First, the core bulk material is bound together over time by mycelium growing into and around common bulk agricultural waste such as cotton hulls. Then, reinforcing layers made from natural fibers (e.g., hemp) inoculated with fungal cells are applied to the core faces, allowed to infiltrate the laminate and bind to the core material, and then heated to inactivate the growth process to make a resilient composite sandwich structure.<br/><br/>The broader impact/commercial potential of this project encompasses the development of mycelium composite materials that are customizable for a broad range of markets including, but not limited to, automotive, transportation, architectural, biomedical, sports, and recreation. These materials are truly sustainable since both the laminates and cores consist of renewable materials. These composites will also require significantly less energy to make than other biocompatible composites because the material is grown instead of synthesized, and the material is completely compostable at the end of life. The outcome of the proposed research and development will be a basic understanding of how to manufacture the composites, the range of material properties obtainable, and how to adjust material properties for particular markets. Through this project, we will partner with researchers and students at two local universities with known expertise in composites manufacturing and testing. If successful with mycelium composites, these materials will find applications in a very high-margin market (i.e. composites) that is sorely needing more sustainable innovations.