Fabricating Mycelium-Agrowaste 3D Composite Materials for Use in Building Construction Insulation.

Environmental degradation is occurring at an alarming rate due to the unsustainable activities of the construction industry posing a serious threat to our ecosystem, human health, and economy¹. Its adverse consequences propel the three planetary crises we are encountering currently: climate change, biodiversity loss, and pollution². The building sector accounts for 39% of gross annual carbon emissions worldwide including emissions created in producing construction materials³. The strides toward attaining zero net carbon emissions and a toxic-free environment include mainstreaming sustainability, efficient energy use, and an integrated waste management system. The focus of the building industry is recently directed towards the development of bio-based materials to be used in the construction of eco and health-friendly building structures. Traditional polymeric foams, such as polystyrene and polyurethane, are commonly used for thermal insulation in infrastructure and housing construction⁴. Nonetheless, such materials are non-renewable, and their production and use involve complex manufacturing processes with substantial energy inputs. Furthermore, it has been proved that they leach out several toxins, which can bio-accumulate in fish and wildlife, presenting a well-documented environmental health problem⁵. Recently, new environmental-friendly bio-based insulation materials are introduced which often require less energy to be produced than traditional materials. The development of sustainable biopolymer materials is a vital mitigation strategy to achieve clean and profitable solutions to the threats of plastic pollution by polymeric foams in our environment.This work is focused on the development of self-growing materials based on Mycelium-Coffee silverskin combinations that could replace traditional insulation materials. It involves the development of sustainable biopolymer composites composed of Lignocellulosic Agrowastes (Coffee silverskin), obtained from roasted coffee seeds, and fungal mycelium derived from non-pathogenic fungal strains (<i>Pleurotus ostreatus</i>). <i>Pleurotus ostreatus</i> is suitable for growth on coffee silverskin as it produces a diversity of extracellular digestive enzymes, which play important role in lignocellulose degradation. Different mixed proportions of the Agrowaste and mycelium were considered to determine the best condition, which supports the growth of <i>Pleurotus ostreatus</i> on Coffee silverskin to produce the composite material with low thermal conductivity and density suitable for thermal insulation applications. Studies on the thermal conductivity revealed that the values of the biocomposites were quite low ranging between 0.04 to 0.12 k(W/mK). Other characterization analyses including mechanical characterization tests and humidity sorption capacity, were also conducted to determine the physico-chemical properties of the developed composite material. The results from the material characterization indicated that the Mycelium-Agrowaste composites can be appropriate for use in building insulation and other suitable applications.<br/>1. Dias, P. P.; Jayasinghe, L. B.; Waldmann, D., Investigation of Mycelium-Miscanthus composites as building insulation material. <i>Results in Materials </i><b>2021,</b> <i>10</i>, 100189.<br/>2. Almroth, B. C.; Cornell, S. E.; Diamond, M. L.; de Wit, C. A.; Fantke, P.; Wang, Z., Understanding and addressing the planetary crisis of chemicals and plastics. <i>One Earth </i><b>2022,</b> <i>5</i> (10), 1070-1074.<br/>3. Huang, L.; Krigsvoll, G.; Johansen, F.; Liu, Y.; Zhang, X., Carbon emission of global construction sector. <i>Renewable and Sustainable Energy Reviews </i><b>2018,</b> <i>81</i>, 1906-1916.<br/>4. Vo, C. V.; Bunge, F.; Duffy, J.; Hood, L., Advances in thermal insulation of extruded polystyrene foams. <i>Cellular Polymers </i><b>2011,</b> <i>30</i> (3), 137-156.<br/>5. Lithner, D.; Larsson, Å.; Dave, G., Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition. <i>Science of the total environment </i><b>2011,</b> <i>409</i> (18), 3309-3324.