TWO EDIBLE MUSHROOMS

This study evaluated the effect of different lignocellulosic substrates on the mycelial growth performance of Pleurotus tuberregium and Psathyrella atroumbonata, two indigenous edible mushrooms of nutritional and economic significance in Nigeria. Five agro-residues including oil palm fiber corn straw, corn husk, plantain leaves, and sawdust were prepared as substrates following pasteurization procedures. Pure cultures of Pleurotus tuberregium and Psathyrella atroumbonata were inoculated into the substrates and incubated at 35°C under controlled humidity (75-80%). Mycelial growth parameters, including radial extension, growth rate, and morphological density, were measured at three-day intervals. The results revealed that substrate composition significantly influenced mycelial colonization and growth rate. For Pleurotus tuberregium, plantain leaves supported the highest mycelial extension after three days, followed by oil palm fiber, while corn husk exhibited the least growth. In contrast, Psathyrella atroumbonata recorded its best performance on oil palm fiber and sawdust, with the least growth again on corn husk. Mycelial density and morphology varied across substrates, with dense and woolly growth observed on oil palm fiber and plantain leaves, indicating vigorous metabolic activity, while sparse or thin mycelium was associated with corn husk, reflecting nutrient limitation and structural rigidity. The comparative growth rate analysis showed that Psathyrella atroumbonata (27.06 mm day') grew faster than Pleurotus tuberregium (22.39 mm day'), suggesting species-specific enzymatic adaptation and differential substrate utilization. The study establishes that substrate selection is a critical determinant of mycelial performance in mushroom cultivation. Plantain leaves and oil palm fiber emerged as the most efficient substrates for Pleurotus tuberregium and Psathyrella atroumbonata, respectively, due to their favorable carbon-nitrogen balance, moisture retention, and porosity. The findings highlights the potential of agricultural residues as contributing to both waste reduction and enhanced food.