Life Cycle Assessment of Fungal-Based Composite Bricks

Fungal-based composites as substitutes for construction materials might represent a promising solution to reduce the environmental burdens of the building industry. Such composites can be produced biotechnologically through the cultivation of multicellular fungi that form dense mycelia whilst growing into and onto residual plant biomass from agriculture and forestry. As comprehensive environmental assessments are missing, this paper conducts a life cycle assessment for fungal-based composite bricks considering the categories of climate change, eutrophication, acidification, smog, water scarcity, and land use. Electricity for sterilization, incubation, and the drying process led to 81.4% of a total 0.494 total kg CO2 eq. for climate change and 58.7% of a total 9.39 x 10(-4) kg SO2 eq. for acidification. Further, hemp shives and grain mix were identified as hotspots for eutrophication (77.7% of 6.02 x 10(-4) kg PO4-3 eq.) and land use (81.8% of 19.4 kg Pt eq.). However, the use of hemp shives, rapeseed straw, or poplar wood chips did not differ in the environmental impacts. Further, lab-scale production was compared with industrial scale-up, which is mostly characterized by energy efficiency showing reduced impacts for all considered categories, e.g., a decrease of 68% in climate change. Recycling should be included in future studies as well as considering the use and end-of-life phase.