In this research, bacteria resistant to heavy metals were isolated from contaminated areas. The ability of bacteria to produce nanoparticles was then evaluated.The biosynthesis of nanoparticles using bacteria is a simple and environmentally friendly method. In this research, the heavy metal-resistant bacterium MKH1was used for the synthesis of silver nanoparticles through reduction of blue Ag+. Biosynthesized silver nanoparticles were characterized by UV-vis spectroscopy,scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results of UV-Vis spectroscopy showed that the peak at about 420 nm, which is related to the absorption band of silver nanoparticles, is characteristic of silver nanoparticles.SEM images also showed that the biosynthesized nanoparticles were mostly spherical and had an average diameter of 30to 60 nm.Besides,the antibacterial properties of the synthesized nanoparticles were evaluated against five pathogenic bacteria in this research and the results showed that the synthesized silver nanoparticles had the highest antibacterial activity against Staphylococcus aureus (25.5±0.7) and the lowest activity against Pseudomonas aeruginosa (11.3±1.2).
