Growth performance and nutritional, mycochemical and bioactive profiling of Volvariella volvacea cultivated on tropical agricultural wastes

Agricultural wastes such as Gmelina sawdust, cassava peels and oil palm pressed fibre are abundantly generated in tropical Nigeria and constitute environmental nuisance. This study evaluated the bioconversion potential of these wastes for cultivation of Volvariella volvacea and profiled the growth performance, nutritional, mycochemical and bioactive properties of the fruiting bodies. Volvariella volvacea was cultivated on three substrates: Gmelina sawdust (VVGS), oil palm fruit pressed fibre (VVOPF) and cassava peels (VVCP) in triplicates. Growth parameters including spawn run, pinhead formation, yield and biological efficiency (BE%) were determined. Molecular identification was confirmed using ITS, LSU and RPB2 markers. Proximate, mineral and vitamin compositions were determined by AOAC methods and HPLC. Mycochemicals were profiled by HPLC. Antioxidant activity was evaluated by DPPH, FRAP and total phenolic content, and antimicrobial activity by agar well diffusion and MIC against six clinical pathogens. All substrates supported mycelial growth and fructification with significant differences (p<0.05). Spawn run ranged from (10.1-12.0) days, with cassava peel best substrate showing the shortest period, oil palm fruit fibre showed highest BE among the three agro waste substrates of 74.2%. Fruiting bodies were rich in protein (10.2-12.3 mg/100 g/dry weight), high content of fiber, ash, and carbohydrate but low fat content. Abundant content of K, P, Ca, Fe and Zn. Vitamins B-complex and D2 were also detected. Phenols, terpenoid, alkaloids and saponins-like compounds were present with total phenols ranging from (1.5-1.63 mg GAE/g). Extracts exhibited dose-dependent DPPH scavenging (IC50 3.8-4.0 mg/mL), FRAP (10.10-10.2 mmol Fe2+ eq/g) and broad-spectrum antimicrobial activity (zones 11.9-17.4 mm, MIC 50.0 mg/mL), with cassava peel substrate showing highest bioactivity among the three agro waste substrates. Tropical agricultural wastes can be valorized for sustainable cultivation of nutritionally and bioactively rich Volvariella volvacea, with cassava peel and oil palm fruit fibre as most suitable substrate for food and nutraceutical applications in the study area.