Advances in Measuring the Biodegradability of a Hybrid Material Resulting from the Transformation of Plastic and Organic Waste with the Oyster Culinary-Medicinal Mushroom Pleurotus ostreatus (Agaricomycetes).

Fungi are recognized as among the most effective microbial agents for plastic degradation due to their production of extracellular enzymes, including lipases, cutinases, esterases, proteases, dehydrogenases, hydrolases, laccases, peroxidases, and oxidoreductases. These enzymes target ester and carbon-carbon bonds in plastics, breaking them down into smaller molecules that fungi can metabolize as carbon sources. In 2014, a process was patented in Colombia and the United States that utilizes macromycetes to transform various cafeteria wastes, including polyethylene, polypropylene, and polystyrene cups; cardboard cups; napkins; solid waste such as bread and cake scraps; and liquid residues from coffee, sodas, chocolate, and milk into a biodegradable hybrid material. This study employed a mixture of polystyrene and coffee grounds as the waste substrate, inoculated with an oyster mushroom, Pleurotus ostreatus, to convert the plastic-organic blend into a more environmentally benign material. Throughout incubation, changes in coloration, biofilm formation on the surface, and other physical transformations were systematically monitored. Biodegradation progress was documented via photographic records and stereomicroscopy. To quantify chemical alterations, Fourier-transform infrared spectroscopy (FT-IR) was employed, demonstrating its effectiveness in confirming modifications to the hybrid material's chemical composition and enabling critical evaluation of the mycelium's impact on expanded polystyrene. The findings indicate significant degradation of polystyrene, suggesting complex biochemical interactions that yield a novel material that continues to degrade over time, akin to that of organic compounds.