Pleurotus ostreatus production on Cannabis sativa, L. (Industrial Hemp) Residues for Edible Mushrooms and Mycelium-based Composites

The current anthropogenic practices of generating single-use waste streams in agriculture, forestry and manufacturing industries have created a host of environmental health problems. Humankind's reliance on non-renewable resources for the production of food and materials, and its current approach to product design and development, are clearly unsustainable. One mitigation strategy to reducing industrial and municipal solid waste, as well as environmental pollution, can be found in using white rot fungi to valorize our planet's most abundant and regenerative natural resource – plant biomass containing lignocellulose. From residual dry plant matter, white rot fungi can be employed through a solid-state fermentation process to produce a variety of edible, nutrient-dense saprotrophic mushrooms in addition to biologically augmented composite materials. Under the framework of the circular economy, agricultural and forestry byproducts with fibers containing lignin, cellulose and hemicellulose may be used as a feedstock for the production of both food and biomaterials – keeping plant biomass revolving through multiple cycles of use and reuse for a variety of product outputs that are biodegradable and help to sequester carbon. In this study, mushrooms were grown on a variety of lignocellulosic substrates derived from agricultural and forestry residues. Hemp-based substrates performed the best of the feedstocks with regard to mushroom yield and mycelium colonization time. Additionally, a number of mycelium composite products were designed and fabricated in this study using residual lignocellulosic plant biomass, including: insulation bricks, acoustical panels, and biodegradable planter pots. In particular, spent mushroom substrate containing hemp hurd and other agricultural and forestry residues showed significant potential in upcycling lignocellulosic plant biomass for the production of both mushrooms and mycelium materials. Regenerative design practices demonstrated how food and materials can be generated from the same lignocellulosic feedstock; therefore, reducing waste, circulating products and materials, and ultimately regenerating nature.