Investigating the Antimicrobial Effects of Silver Nanoparticles Synthesized by Bacteria Isolated From Agricultural Soils of Kerman, Iran

Abstract

Background and Aims: The use of microorganisms in the synthesis of metal nanoparticles is known as an eco-friendly method. Moreover, because of the ability of microorganisms to synthesize nanoparticles of various sizes, shapes and morphologies, this method has gained extreme attentions in recent years. The aim of this study was, therefore, to investigate the antimicrobial effects of silver nanoparticles synthesized by bacteria isolated from agricultural soils of Kerman, Iran. Materials and Methods: This study was carried out in 2014. Silver nanoparticles were characterized by SEM, EDS and XRD analyzes. The antimicrobial effects of silver nanoparticles were also assessed against some pathogenic bacteria. Results: Of the 40 silver nanoparticle producing bacteria, the strains that were able to produce silver nanoparticles with high antimicrobial activity yielded under different environmental conditions, were selected. The results of scanning electron microscopy (SEM) confirmed the presence of silver nanoparticles with a spherical shape. EDS analysis showed that silver content of the particles was about 60 wt %. Sequence alignment and phylogenetic tree results showed that M9 and B7 strains are closely related to Bacillus cereus and Pseudomonas argentinensis, respectively, with 99% homology. Conclusions: The results showed that the M9 and B7 strains can synthesize silver nanoparticles with high antimicrobial effects under different environmental conditions.

Keywords

• Biosynthesis
• Silver nanoparticles
• Bacillus Cereus
• Pseudomonas
• Antimicrobial effect