Green Synthesis of Silver Nanoparticles Using Pleurotus ostreatus

Aims: The study aimed to synthesize silver nanoparticles (AgNPs) from aqueous AgNO3 using phytochemicals present in Pleurotus ostreatus and assess the AgNPs antibacterial activity on Bacillus subtilis and Providencia rettgeri.

Study design: Experimental/Analytical.

Place and Duration of Study: Bells University of Technology between December 2020 and August 2021.

Methodology: The mushroom was washed, dried, pulverized and 5g stirred into 100ml deionized water. The solution was sonicated using ultrasonic cleaner at 40 oC for 40 min, centrifuged at 4000 rpm for 10 min. The supernatant was filtered, and 1ml filtrate was mixed with 9 ml of 10mM AgNO3. After the reaction period, the mixture was centrifuged at 15,000 rpm for 15 min. The residues were washed thrice with deionized water and dried.

Synthesis of AgNPs was monitored by UV–Vis spectrophotometer, characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction analysis. Antibacterial analysis was done by agar well diffusion using gentamicin as control.

Results: A dark brown colour change and UV visible spectroscopy peak at 400 nm confirmed the formation of AgNPs. Fourier transform infrared spectroscopy analysis showed the presence of functional groups involved in the reduction of AgNO3. GCMS performed on the methanolic extract of Pleurotus ostreatus showed the presence of 37 organic compounds, among them were cathecol, hydroquinone and phenols etc. Antimicrobial activity revealed that AgNPs inhibited the growth of B. subtilis and P. rettgeri.

Conclusion: The study revealed that Pleurotus ostreatus effectively synthesized AgNPs and the AgNPs inhibited the growth of Providencia rettgeri and Bacillus subtilis and can play major roles in the field of medical and pharmaceutical nanotechnology.