PHYSICOCHEMICAL COMPOSITION OF SPENT OYSTER MUSHROOM SUBSTRATE

Mushroom substrate is a type of lignocellulosic material that helps promote the growth, production, and fruiting of mushrooms. The substrate contains components rich in organic matter due to the modification of the material after harvesting of mushrooms. This study analysed the physicochemical composition of spent oyster mushroom substrate (SOMS) by comparing with sterile fresh mushroom substrate (SFMS). The physicochemical analyses conducted were moisture content, ash content, pH, primary macronutrients (nitrogen, phosphorus, and potassium), secondary macronutrients (calcium and magnesium), micronutrients (iron, manganese, copper, and zinc), and carbon-to-nitrogen (C:N) ratio. The results obtained for moisture content, ash content, pH, and C:N ratio showed higher values for SOMS. The values of moisture, ash content, pH, and C:N ratio increased to 63.00%, 6.58%, 5.92, and 116.29, respectively. For the nutrients in the mushroom substrate, namely phosphorus, calcium, magnesium, iron, and copper, the values after cultivation increased to 57.14 ppm, 7366.67 ppm, 1230.83 ppm, 85.18 ppm, and 3.75 ppm, respectively. Meanwhile, the values of nitrogen, potassium, zinc, and manganese decreased to 0.38%, 706.67 ppm, 16.90 ppm, and 68.65 ppm, respectively. Sulphur content was detected in SFMS but absent in SOMS. In conclusion, mushroom cultivation changed the physicochemical composition of the mushroom substrate