Formation of Se(0) nanoparticles by bacteria

In the present study we investigated the interaction of selenium with Azospirillum brasilense as well as Bacillus and Lysinibacillus strains from a uranium mining waste pile. The biosynthesis of hardly soluble nanospheric Se(0) was observed for A. brasilense only in the presence of Se(IV) under aerobic conditions. After isolation of the Se(0) from the biomass, the characteristics of the nanoparticles were intensively studied by different techniques, namely HG-AAS, ICP-MS, PCS and SEM-EDX. In summary A. brasilense produced very homogeneous nanospheres with highly negative surface charge and a size of 410 ± 110 nm. The Bacillus and Lysinibacillus strains are able to induce red Se(0) nanoparticles after one day of incubation with Se(IV).