The potential of sawdust substrate of some tree species in the cultivation of the oyster mushroom, Pleurotus sajor-caju, was evaluated. Sawdust was collected from wood processors in various sawmills at Ibadan, southwest Nigeria and composted for mushroom cultivation. Biological efficiency (BE) of P. saju-caju on the various wood substrates and proximate analysis were carried out to determine rate of substrate utilization and nutritional value of harvested mushrooms using standard procedures. Spawn run period of the composted substrate bags ranged between 21 and 29 days. Mushroom cultivated on Brachystegia eurycoma and Gmelina arborea substrates had the highest total fruit body yield of 172.8 and 168.2 g respectively at harvest. Biological efficiency (BE) varied considerably between 17.3 and 37.7%. B. eurycoma had the highest BE of 37.7%. Production rate (TP) was also highest in mushrooms cultivated on B. eurycoma and G. arborea sawdust with TP of 64.0 and 62.5% respectively. Analyzed samples showed significant amounts of crude fibre, protein, and carbohydrate that varied from 9.3-15.1, 18.2-30.2 and 37.7-51.5% respectively. Also, calcium, magnesium and phosphorus content varied from 27.3-30.1, 27.6 - 44.2 and 37.6 - 60.04 mg /100g-1 respectively. Lipid constituent was generally ≤ 1.5%. However, the utilization of these agro forestry wastes for the production of oyster mushrooms could therefore be economically and ecologically practicable.

Keywords: Fruiting body production, sawdust, Pleurotus sajor-caju, biological efficiency, proximate composition.