Extracellular Biosynthesis of Silver Nanoparticles using the Fungus Pleurotus ostreatus and their Antibacterial Activity

Abstract

In the present study, an eco-friendly process for the synthesis of nanomaterials using a fungus (Pleurotus ostreatus) has been attempted. The fungus supernatant of seed culture was used for the biosynthesis of silver nanoparticles. The aqueous silver ions were reduced to silver metal nanoparticles when treated with the fungal supernatant.  After 72h of treatment, silver nanoparticles  were  obtained.  These  silver  nanoparticles  were  characterized  by  UV–Vis spectroscopy, scanning electron microscopy (SEM), electron diffraction spectroscopy (EDX) and X-ray diffraction (XRD). The nanoparticles exhibited maximum absorbance at 440 nm in UV–Vis  spectroscopy.  The  XRD  spectrum  of  silver  nanoparticles  exhibited  2θ  values corresponding to the silver nanocrystal. SEM micrographs revealed the formation of well- dispersed silver nanoparticles of 50 nm, and the presence of silver was confirmed by EDX analysis.  The microbes  selected  for the present  study for the antibacterial  activity were Escherichia coli, Klebsiella pneumoniae,  Pseudomonas aeruginosa, Staphylococcus aureus and Vibrio cholera. They were obtained from Armats  Biotek , Chennai India. The present study  concludes  that  nanoparticle  synthesized  from  the  fungus   opens  up  the  exiting possibility of rational strategy of biosynthesis of nonomaterials and thus silver nanoparticles has great potential as antimicrobial compound against pathogenic  microorganisms  studied and that it can be used in the treatment of infectious diseases caused by bacteria.

Keywords: Silver nanoparticles, Pleurotus ostreatus, Antimicrobial activity