Ganoderma lucidum-Driven Fabrication of bagasse-sawdust mycelium-based biocomposites: effects on mechanical strength and water absorption

Mycelium-based biocomposites offer a promising approach to converting lignocellulosic residues into value-added materials. In this study, Ganoderma lucidum was used to fabricate mycelium-based biocomposites from sugarcane bagasse (BMC) and a bagasse-sawdust mixture (BSMC). Different bagasse-to-sawdust formulations were preliminarily screened based on visual assessment of mycelial colonization, and the 10:1 bagasse-to-sawdust ratio was selected for further investigation rather than as an optimized formulation. The resulting composites were evaluated for bulk density, shrinkage, compressive strength, water absorption, structural characteristics, thermal degradation, and soil-burial degradation. The bulk density of BSMC (0.1797 ± 0.0028 g cm^-3) was slightly higher than that of BMC (0.1692 ± 0.0092 g cm^-3), but the difference was not statistically significant. Compared with BMC, BSMC showed significantly lower shrinkage (15.39 ± 0.96%) and water absorption (45.00 ± 1.18%), and significantly higher compressive strength (341.70 ± 5.09 kPa), whereas BMC values were 18.83 ± 0.99%, 53.60 ± 1.38%, and 300.73 ± 5.93 kPa, respectively. FTIR and SEM analyses showed differences in the structural and microstructural characteristics of the composites, with interconnected hyphal networks observed in both formulations. Thermal analysis revealed differences in degradation behavior between the two composites. After 90 days of soil burial, BMC and BSMC showed mass losses of 56.65 ± 1.30% and 52.10 ± 1.00%, respectively, indicating progressive soil-burial degradation. Overall, the findings demonstrate that substrate formulation influenced the measured physical, mechanical, water absorption, structural, thermal, and soil-burial degradation properties of G. lucidum-based mycelium biocomposites.