Green application and toxic risk of used diaper and food waste as growth substitute for sustainable cultivation of oyster mushroom (Pleurotus ostreatus)

Used diaper and food waste form a major proportion of wastes piled up in landfill. This study aims to reduce used diaper and food wastes (comprising coffee waste, sugarcane bagasse, banana skin, eggshell) via converting them into a unique formulated growth substrate, providing an alternative of growth medium in mushroom cultivation. The growth media showed high content of cellulose (27%), hemicellulose (16%) and high nutrients with nitrogen (15,779 mg/kg), phosphorus (867 mg/kg) and potassium (7,758 mg/kg), promoting nearly two-fold mushroom production (73 g) compared to commercial media (37 g). The mushroom cultivation also led to a 40% reduction in weight of growth substrate, confirming its efficient utilization for growing mushroom while simultaneously leading to waste reduction. The mushroom harvested showed similar metabolite profile to that cultured by commercial media via profiling using nuclear magnetic resonances. The results indicated similar biological composition and no accumulation of undesired toxic and biological components that might be derived from the waste-formulated substrate, thus providing assurance that it is safe to be used for sustainable mushroom cultivation.