Biochar End Uses - Oral Presentation
Achieving circularity in the mushroom industry: Biochar from spent mushroom substrate
Harshal Kansara - Lead
Madan Manipati
Yvan Hernandez-Charpak
Christopher Carter
Luke Luft
Jeffrey Hallowell
Thomas Trabold

Rochester Institute of Technology
Empire Medicinals
Biomass Controls PCB

Mushrooms have unique culinary and medicinal properties that have motivated strong growth of the global industry over the past several decades. After the fruited body of the mushroom is harvested for sale, spent mushroom substrate (SMS) is generated as a waste stream that poses serious economic and environmental burdens. This research explored the technical viability of converting SMS into biochar via pyrolysis, and then blending this biochar into the baglog medium for the next generation of mushroom growth.

Biochar was produced using both laboratory- and commercial-scale systems to pyrolyze SMS generated from production of three mushroom species: Shiitake (Lentinula edodes), Blue Oyster (Pleurotus ostreatus), and Lion's Mane (Hericium erinaceus). The laboratory experiments enabled fine control of the primary operational factors affecting biochar properties in an inert atmosphere. For the commercial-scale tests, we utilized the “Biogenic Refinery” system manufactured by Biomass Controls PBC. Biochar materials produced on both platforms were characterized through a standard protocol comprised of in-house measurements and 3rd-party laboratory measurements to quantify elemental and nutrient content, bulk density, surface area, etc. The results follow expected trends with variation in operational parameters, but most importantly confirmed that SMS-derived biochar materials meet stringent standards for contamination for all applications, including animal feed, conventional and organic farming, and composite materials.

The SMS biochar materials were used in growth trials for all three species of mushrooms, which included hardwood-derived biochar procured from Seneca Farms Biochar (Odessa, NY) as a commercial baseline. Biochar was blended at various mass loadings into the standard baglog mixture comprised of hardwood sawdust, soy meal, sunflower meal and cracked corn. The resulting impact on mushroom growth was assessed by comparative analysis of the time to full mycelium colonization of the baglog, and mass yield of the final fruited body mushroom product. The initial results show a reduction in the time to full colonization for some biochar baglog recipes, with the effect appearing to be much more significant for Lion’s Mane than Blue Oyster. There is also evidence that biochar loading around 5% by mass can significantly increase yield of the mushroom fruited body. These benefits, coupled with the potential to recover waste heat for process thermal energy demand, contribute to the economic and environmental sustainability of the circular SMS-to-biochar model.

Keywords: myceliumfruited bodyBiogenic Refinerypyrolysiscircular econonomy