Evaluation of the Production of a Biocomposite Material from a Lignocellulosic Waste Mixture using Mycelium of Pleurotus ostreatus

This study investigated the fabrication of a biobased material utilizing the Pleurotus ostreatus strain, with malt dust, coffee husks, and sugarcane bagasse serving as substrates. Six substrate mixtures were formulated and subjected to solid-state fermentation. The most effective formulation—comprising 50% sugarcane bagasse and 50% malt dust—achieved complete (100%) surface colonization. After 25 days of fermentation, significant increases of 54.5% in soluble lignin and 123.2% in protein concentrations were observed, accompanied by an 11.3% decrease in pH and a reduction of 0.118 g/mL in reducing sugars. These changes suggest strong metabolic interactions between the microorganism and agro-industrial residues, indicating efficient nutrient assimilation and promoting the formation of aerial mycelia in a reticulated structure, a key feature for the development of lightweight and insulating biomaterials. Although the biomaterial exhibited an average compressive stress of 255.5 ± 27.9 kPa, it has not yet reached the mechanical performance of EPS. However, these results represent a promising step forward in the development of sustainable materials.