Abstract:The contamination of groundwater by uranium mining, particularly from the acid leaching process, has become an urgent environmental issue that needs immediate attention. The differences in desulfurization and uranium removal efficiencies of sulfate-reducing bacteria (SRB) isolated from various sources in uranium-contaminated groundwater were investigated. Four SRB strains were selected for the experiment: A3m-21ZLL, A1SXC21Q, C31YC21D and GnLF21. These strains were isolated from different environmental sources, including abandoned farmland soil near the uranium mining area, acid-leached uranium-contaminated groundwater, uranium leachate tailings, and landfill leachate. The goal of this research is systematically compare their sulfate reduction capacity and their potential for uranium removal under different uranium concentration gradients in groundwater. The results clearly demonstrate that the origin of the SRB strains plays a significant role in their desulfurization and uranium removal abilities. The strain A1SXC21Q, isolated from soil samples around abandoned farmland near the uranium mine, exhibites the best performance in groundwater with uranium concentrations of 3—5 mg/L. After 72 hours, this strain can able to completely remove sulfate, and its uranium removal efficiency reaches 100%. This suggests that SRB strains enriched from uranium-contaminated agricultural soils may be particularly effective for groundwater bioremediation in environments with relatively low uranium concentrations. In contrast, the strain C31YC21D, which is enriched from acid-leached uranium-contaminated groundwater, shows the best performance in the 7—10 mg/L uranium concentration range. After 72 hours, its uranium removal efficiency exceeds 80%, highlighting its potential in environments with moderate uranium contamination. This suggests that strains enriched from actual mining areas or acid-leach sites might be more suitable for bioremediation under higher uranium concentrations. On the other hand, strains A3m-21ZLL isolated from uranium leachate tailings, and GnLF21 isolated from landfill leachate, demonstrate lower removal efficiencies. Particularly, GnLF21 shows poor desulfurization and uranium removal performance, especially in high uranium concentration environments. This indicates that certain SRB strains may be less effective in specific contaminated environments and emphasizes the need for a tailored approach when selecting SRB strains for bioremediation. In conclusion, this study provides valuable insights into the selection of SRB strains for the bioremediation of uranium-contaminated groundwater. The findings suggest that strain selection should be based on the specific environmental conditions of the contamination site, such as the source of the contamination and the concentration of uranium, to optimize the effectiveness of in-situ bioremediation processes. By choosing the right strains for specific contamination environments, the efficiency of uranium removal and sulfate reduction can be significantly improved, contributing to more effective and sustainable environmental remediation strategies.