Investigation of properties and applications of cellulose-mycelium foam

Innovative sustainable products can contribute to slowing climate change while simultaneously driving economic growth. In this study, we describe a ‘green’ technology to produce a porous, lightweight cellulose-mycelium foam (CMF) in which fungal mycelium is grown for applications such as filtration, packaging, and bioremediation. Fluorescent microscopy revealed incomplete fiber degradation after 25 days of fungal growth, and that mycelium grew along fibers and within the pores of the CMF. The physio-mechanical properties of the CMF were investigated via compressibility, thermogravimetric analysis, and dry and wet tensile strength for samples grown for 0, 15, and 25 days. Thermal stability increased with mycelium growth, showing extrapolated onset temperatures of 227.5 °C, 312.7 °C, and 325.5 °C for 0, 15, and 25 days, respectively. Tensile strength and compressibility were notably improved with mycelial growth. CMF permeability, filtration efficiency, and pressure drop were tested, and we observed a decrease in permeability with mycelium growth in foam fiber, and hydraulic filtration efficiency measured 99.9% for particles sized 20 µm or larger. Living CMF neutralized potassium hydroxide leaks from alkaline batteries, decreasing pH from 12 to 6 over a 60-day period. These results demonstrate a wide range of material improvements, showing promise for practical filtration, thermal insulation, and bioremediation applications while being both sustainable and biodegradable.