Abstract

The study investigated the proximate and phytochemical composition of sawdust substrates from four tropical wood species; Pterocarpus santalinoides, Mitragyna ciliata, Musanga cecropioides and Hevea brasiliensis and their effects on the yield of Pleurotus ostreatus (Jacq. ex Fr.) Kummer. Proximate parameters included ash, moisture, crude fibre, lipid, protein and carbohydrate, while phytochemical analyses assessed alkaloids, flavonoids and saponins. Fruit-body morphology and yield were evaluated across three flushes, with treatment means compared using Duncan’s Multiple Range Test at 5% probability. Substrate composition varied considerably. Ash ranged from 0.21% in H. brasiliensis to 2.87% in P. santalinoides, moisture from 7.51% in M. ciliate to 17.52% in H. brasiliensis, and crude fibre from 38.74% to 56.31%. Crude lipid ranged from 0.46% to 11.74%, protein from 1.05% to 1.25%, and carbohydrate from 13.17% to 48.60%. M. ciliata recorded the highest alkaloids (7.14%), flavonoids (13.10%) and saponins (5.72%), whereas H. brasiliensis had the lowest values. Morphologically, fresh and dry weights ranged from 48.91-110.87 g and 3.38-9.61 g, respectively. H. brasiliensis produced the highest overall yield, while P. santalinoides recorded the largest cap diameter (11.0 cm). The findings indicate that mushroom productivity depends on combined substrate characteristics rather than carbohydrate concentration alone. H. brasiliensis sawdust is therefore recommended for high mushroom yield, while P. santalinoides may be preferred for larger caps and sustained production.