Optimization of Growth Conditions of Desulfovibrio desulfuricans Strain REO-01 and Evaluation of Its Cd(II) Bioremediation Potential for Detoxification of Rare Earth Tailings

Summary

Researchers studied a special bacterium found in rare earth mining tailings that can remove harmful cadmium and reduce sulfate contamination. By optimizing growing conditions like temperature, pH, and food sources, they found the bacterium could remove over 95% of cadmium and reduce sulfate levels significantly. This discovery offers a promising environmentally-friendly method to clean up contaminated mining sites.

Background

Ion-adsorption rare earth tailings contain high sulfate concentrations and heavy metals like cadmium that contaminate soil and groundwater. Conventional physicochemical remediation methods are costly and inefficient. Sulfate-reducing bacteria offer sustainable alternatives for bioremediation through metal immobilization via sulfide production.

Objective

To comprehensively evaluate the physiological characteristics, environmental adaptability, and bioremediation potential of Desulfovibrio desulfuricans strain REO-01 for simultaneous sulfate reduction and cadmium immobilization in rare earth tailings.

Results

REO-01 achieved over 95% Cd(II) removal (0.2 mM to 3.33 μM) and 66.16% sulfate reduction in 96 hours. Optimal growth occurred at 25-40°C and pH 6-7. Sodium lactate at 4.67 g/L was the most effective carbon source, reducing ORP to -325 mV and lowering Cd(II) and sulfate to 3.33 μM and 510 mg/L respectively.

Conclusion

Strain REO-01 is a neutrophilic sulfate-reducing bacterium with excellent environmental resilience and strong bioremediation performance for co-treatment of heavy metals and sulfate in rare earth tailings. These findings support its application in in situ bioremediation and resource utilization strategies for contaminated tailings.
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