Comparison of antimicrobial effects of silver and copper nanoparticles and chlorinated chemicals on Bacillus subtilis and Bacillus cereus spores and vegetative cells

Antimicrobial properties of silver and copper nanoparticles were examined on B.cereus PTCC(1247), B.subtilis PTCC(6633). Active chlorine in sodium hypochlorite was causing the antimicrobial properties. The purpose of this study is the bactericidal effect of metal nanoparticles has been attributed to their small size and high surface to volume ratio, which allows them to interact closely with microbial membranes and is not merely due to the release of metal ions in solution. The antimicrobial effect of nanoparticles were quantified based on diameter of inhibition zone in the disk diffusion tests and well diffusion tests conducted in plates and by determining the minimum growth inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nanoparticles in liquid batch cultures. Antimicrobial effects of nanoparticles and sodium hypochlorite were studied by counting colonies in different hours and dilution with cultured purplate and two layers methods. In this study was observed that B.subtilis depicted the highest sensitivity to nanoparticles compared to B.cereus and was more adversely affected by the silver nanoparticles. So that B.subtilis (MIC) of silver nanoparticles was measured 7 ppm and the nanoparticles of copper was measured 50 ppm, and sodium hypochlorite was measured 700 ppm. B.subtilis spores were killed in less dilution of antimicrobial substances and in zero time. B.subtilis spore and vegetative cell were more sensitive than the silver nanoparticles. The results indicated silver nanoparticles were more effectiveness compared to other antimicrobial substances that used in this stduy.