Sustainable application of medicinal residue as a replacement substrate for Gray Oyster mushroom (<i>Pleurotus ostreatus</i>) cultivation

The circular economy encourages sustainable resource use and waste reduction. This study investigates the potential of using medicinal residue, a by-product from the herbal medicine industry, to replace sawdust in cultivating gray oyster mushrooms ( Pleurotus sajor-caju ). Medicinal residues contain bioactive compounds such as polysaccharides and saponins, making them a promising substrate alternative. However, their effectiveness in fully replacing sawdust remains uncertain. This research aims to identify the optimal mixture of medicinal residue and sawdust through six treatments, evaluated using the One-Factor-At-a-Time (OFAT) experimental design method. The parameters assessed included mushroom length, cap width, weight, and bioactive compound content. The results showed that the 80% medicinal residue and 20% sawdust treatment yielded the best outcomes, with significant improvements in mushroom size and bioactive compound levels. The 100% medicinal residue treatment, however, led to poorer growth, indicating the need for sawdust to support substrate structure. These findings suggest that medicinal residues can partially replace sawdust in mushroom cultivation, contributing to sustainable agriculture and waste management. Further research is needed to assess scalability for commercial applications.