This study investigates selenium (Se) biofortification in four strains of the medicinal mushroom Hericium erinaceus using Se-enriched substrates to assess Se uptake, distribution, and its impact on yield. Experimental substrates included lignocellulosic materials fortified with Se (0, 2, 6, and 18 µg/g) in the form of sodium selenite. Se accumulation varied by strain, with M9521 showing the highest bioaccumulation efficiency, particularly for an unknown Se compound, suggesting unique metabolic pathways. Other strains predominantly accumulated selenomethionine. The bioconcentration factor was highest at 6 µg/g Se, indicating optimal efficiency at this level. Moderate Se supplementation (2–6 µg/g) improved yield, though time to harvest was affected by Se levels in some strains. Substrate composition influenced Se uptake, with wheat bran yielding the highest Se content and soybean hulls maximizing biological efficiency. A strong correlation between C/N and Se content was observed. Se distribution was higher in outer basidiocarp layers, and light intensity during cultivation enhanced Se accumulation. Se uptake decreased with subsequent flushes at medium and high supplementation levels, while substrates maintained the same bioavailable Se. The results highlight the potential of Se-enriched Hericium erinaceus as a functional food source and the role of substrate and cultivation conditions in optimizing Se content.

Mycelium-based biocomposites (MBBs) represent a sustainable alternative to synthetic composites, as they are produced from lignocellulosic substrates bonded by fungal mycelium. Their mechanical performance depends on multiple interacting factors, including the substrate composition, fungal species, and processing conditions, which makes property optimisation challenging. In this study, an artificial neural network (ANN) model was developed to predict two mechanical properties of MBBs, namely internal bonding (IB) and compressive strength (CS). An ANN model was trained on experimental data, using the substrate composition, fungal species, and physical properties of MBBs. The ANN predictions were compared with measured values, and the model accuracy was evaluated. The results showed that the ANN achieved a high predictive accuracy, with coefficients of determination of 0.992 for IB and 0.979 for CS. IB values were predicted more precisely than CS, likely due to microstructural heterogeneities. The heterogeneities were visualised using scanning electron microscopy. Composites produced with Ganoderma sessile and Trametes versicolor exhibited the highest IB. Interestingly, Trametes versicolor achieved the highest CS on virgin wood particles but the lowest values on recycled wood, underlining the strong influence of the substrate quality. The study demonstrates that ANNs can effectively predict the mechanical properties, reducing the number of experimental tests needed for material characterisation.

Summer overheating is an escalating challenge for lightweight timber constructions, which inherently lack the thermal mass of traditional masonry. This study investigates the thermo-physical properties of a mycelium-based biocomposite (MBB) insulation produced from industrial wood waste, with particular focus on volumetric heat capacity (C_v). The C_v and thermal conductivity (λ) of MBB were experimentally measured and benchmarked against seven reference insulation materials spanning bio-based, mineral, and petroleum-derived categories, with results visualized on an Ashby diagram. The areal heat capacity (κ) of nine representative wall assemblies was theoretically calculated per EN ISO 13786. Even though the MBB achieved the highest thermal conductivity (λ = 0.0641 ± 0.0024 W·m⁻¹·K⁻¹) among the tested insulation materials, it offers 4.7 times higher C_v than EPS. Analytical modeling indicates a thermal phase shift of 8.2 h for a 185 mm layer, compared to 4.6 h for EPS. The softwood timber + MBB wall assembly achieved an areal heat capacity approaching the lower boundary of traditional masonry performance. These findings demonstrate MBB’s potential as a bio-based, waste-derived insulation for significantly enhancing the thermal inertia of lightweight timber buildings and mitigating summer overheating risk.