Chemical Changes in Mycelium Biocomposites Induced by Fungal-substrate Interactions

Mycelium biocomposites (MBs) represent a sustainable alternative to conventional polymer foams such as expanded polystyrene and polyurethane. These materials are formed through the colonization of lignocellulosic substrates by the filamentous fungi. Understanding the chemical transformations occurring within the substrate during fungal growth is essential for optimizing biocomposite properties. In this study, substrates composed of silver birch sawdust, sanding dust, and hemp shives were inoculated with Trametes versicolor mycelium. Both the initial substrates and the resulting biocomposites were analyzed using the gravimetric method, pH determination, elemental CHNS analysis, and Fourier-transform infrared spectroscopy (FTIR). Following fungal colonization, a decrease in pH, C/N ratio, and relative lignin content was observed, accompanied by an increase in relative protein and inorganic matter concentrations. These results highlight the chemical changes induced by T. versicolor during substrate colonization, providing insights into the bioconversion processes underlying MB formation.