Selenium Metabolizing Capabilities of 12 Bacterial Strains Isolated from Urban Environmental Samples.

The role of bacterial selenium metabolism in non-polluted environments remains underexplored within the selenium biogeochemical cycle. In this study, selenium-metabolizing bacteria were isolated from urban environmental samples. Among 12 isolates, 10 were identified as spp., while the remaining 2 were and . The isolates demonstrated high selenium-removal efficiency, removing over 95% of 5 mM selenium from the aqueous phase within one week. In contrast, K24-1 and K24-4 removed only 19% and 69%, respectively. A detailed investigation of five representative isolates, K21-1, K24-1, K24-2, K24-4, and K24-5, revealed that spp. efficiently reduced selenate directly to elemental selenium, with minimal accumulation of selenite intermediates. These results highlight spp. as key selenium reducers and suggest their potential as bioindicators of selenium metabolic capacity in the environment.