Bioaccumulation of heavy metals together with medicinal properties of Pleurotus spp cultivated on agro-industrial substrates supplemented with wheat bran and maize flour.

Abstract

Over the years, mushrooms have been used as a source of food and as medicinal therapeutics, with numerous biological properties such as; antimicrobial, anticancer, hepatoprotective, and antidiabetic. Identifying optimum mushroom growing conditions and substrates may improve mushroom productivity, quality, safety, and subsequent biological properties of P. ostreatus mushrooms. Therefore, the current study sought to investigate the effects of supplementing the mushroom-growing substrates on the biological properties of mushrooms. The study also evaluated the ability of Pleurotus ostreatus to accumulate heavy metals from locally available mushroom-growing substrates. Our observations indicated that the P. ostreatus mushroom potentially absorbed heavy metals from all the growing substrates, indicating its potential for bioremediation. The absorption of heavy metal by P. ostreatus was not influenced by the type of substrates used to cultivate the mushroom. The addition of supplements significantly improved the mushroom yield, and biological properties of P. ostreatus. The P. ostreatus mushroom extracts showed significant radical scavenging activity against DPPH and ABTS. Significant antimicrobial activities against Staphylococcus aureus and Escherichia coli were observed. Finally, the study investigated the potential of biosynthesis of zinc oxide nanoparticles (ZnONps) using Pleurotus ostreatus mushroom as the capping and reducing agent. The synthesized ZnONps were stable and proved to have antioxidant and antimicrobial activity against Pseudomonas aeruginosa, E. coli, Klebsiella pneumonia, and Enterococcus faecalis. Finally, the findings suggest that edible P. ostreatus mushrooms grown from supplemented substrates can potentially be used for green synthesis of ZnONPs, and also as an alternative source for antioxidant and antimicrobial products.