Substrate-Driven Modulation of Nutritional Composition and Bioactive Compound Profile in Pleurotus pulmonarius Cultivated on Diversified Agri-Waste.

Pleurotus pulmonarius (Fr.) Quél. is a commercially important edible mushroom recognized for its nutritional and nutraceutical value. However, the influence of alternative agricultural waste substrates on its biochemical composition remains insufficiently characterized. This study investigated the effect of four cultivation substrates, coconut waste (PpC), paddy husk (PpP100), paddy husk supplemented with sawdust (PpP20) and rubberwood sawdust as control (PpS), on the macro- and microelement profile, secondary metabolite composition, and antioxidant activity of P. pulmonarius fruiting bodies. Analytical methods included ICP-MS and FAAS for elemental analysis; GC-MS for fatty acid, carbohydrate and phenolic profiling; Kjeldahl method for total protein; FTIR spectroscopy for structural characterization; and four complementary antioxidant assays (DPPH, ABTS, CUPRAC, FRAP). Coconut waste substrate promoted the highest protein accumulation and elevated concentrations of iron, zinc, and specific phenolic acids (vanillic, protocatechuic). Paddy husk-based substrates favored carbohydrate accumulation, particularly trehalose, while sawdust supported the greatest lipid content, dominated by linoleic acid. Potassium was the predominant macroelement across all variants. Antioxidant activity was highest in PpP100 and PpC across all four assays. FTIR confirmed a mushroom-specific polysaccharide, protein, and lipid profile in all samples. The results demonstrate that agricultural waste represents sustainable, value-added alternatives to conventional sawdust, capable of maintaining or enhancing the nutritional and nutraceutical quality of oyster mushrooms to enhance agricultural production.