Metal Accumulation Using a Bacterium (K-142) Identified from Environmental Microorganisms by the Screening of Au Nanoparticles Synthesis

The use of technology that uses organisms to synthesize metal nanoparticles is necessary to maintain a sustainable society. In this study, we investigated and screened the microorganisms isolated from environmental water by quantifying the reproducibility of synthetic Au nanoparticles and the ability of large amount synthesis. The microorganism (K-142) of the Bacillus genus showed the best activity in the investigation. K-142 can also synthesize Ag, CdS and PbS nanoparticles, and the deposition efficiency of Ag, Al, Cd, Cu, and Pb was about 64.8–99.2%. According to the observation results under the microscope after fluorescent staining, K-142 could survive after being treated with 0.5 mM metal solution for 24 h. Therefore, it is expected that K-142, which is easy to cultivate, would also have a high ability to reduce and deposit metal substances. K-142 can be applied to the concentration and recovery of heavy metals in environmental water, thereby opening up channels for biological water purification.