Screening of strains from wood decay species for advancement of mycelium-based materials technology

Wood decay fungi (WDF) mostly include species in Agaricomycetes. Besides the chemical degradation, WDF hyphae mechanically force the lignocellulosic matrix by high turgor pressure. Several WDF species develop macroscopic, annual or perennial basidiomes, whose consistency is notably tenacious, flexible or rigid, rubber-like or wood-like. Analogous features are displayed by mycelia too, as appreciable in pure culture. If allowed to colonize a 3d-substrate (e.g. saw dust), the fungus gradually replaces the substrate itself and produces a strongly cemented, composite material. If the fungal biomass is completely separable from the substrate (e.g. liquid medium), the final material is composed by mycelia only. Mycelia and its biocomposites were reported in literature for promising physico-mechanical and thermodynamic properties with concern to: low density; thermal and acoustic insulation; fire safety; compressive, tensile and flexural strength; elastic deformation. In- and extra-wall panels, floor tiles, design objects and packaging boxes are examples of mycelium-based products. Whatever is the parameter regarded, the pivotal variable is always the fungal strain. Aims of our research are: isolation of mycelia in pure culture; molecular check of morphological identification; screening based on mycelial mat morphology, selectivity towards substrate, growth rate, cultivation parameters. ITS region analysis resulted indispensible to discriminate cryptic species. Preliminary screening on synthetic media was followed by growth tests on specialized substrates based on the species preference in wild. The selectivity towards different substrate components (basically, cellulose vs lignin) was investigated by coupling thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR).