We analyzed the tolerance of sulfur-oxidizing bacteria to Co and Cs exposure and γ-ray irradiation, and evaluated the feasibility of bioleaching to remove radionuclides from contaminated soil. The soil samples were collected in the vicinity of a nuclear power plant in the Republic of Korea and artificially contaminated with Co and Cs to mimic accidental exposure (initial concentration of Co and Cs were 253 mg/kg and 307 mg/kg, respectively). The applied bacteria were identified as Acidithiobacillus thiooxidans with a 95 % similarity of DNA sequence. The bacteria enabled sulfur oxidation at Co concentration of less than 50 mg/L and irrespective of Cs concentration. In addition, the bacteria showed tolerance to 400 Gy γ-ray irradiation. Overall, the Bioleaching process removed 98 % of Co and 96 % of Cs from the artificially contaminated soil and, compared to control samples, approximately doubled the removal efficiency. These results demonstrate that bioleaching by sulfur-oxidizing bacteria has potential as a remediation strategy for radionuclide contaminated soils.

我们分析了硫氧化细菌对Co和Cs暴露以及γ射线辐照的耐受性，并评估了生物浸出从受污染土壤中去除放射性核素的可行性。土壤样品是在大韩民国一家核电厂附近收集的，并被Co和Cs人工污染以模仿意外暴露（Co和Cs的初始浓度分别为253 mg / kg和307 mg / kg）。所应用的细菌被鉴定为硫代酸性硫杆菌DNA序列具有95％的相似性。该细菌能够在Co浓度小于50 mg / L且与Cs浓度无关的情况下进行硫氧化。另外，细菌显示出对400 Gyγ射线辐射的耐受性。总体而言，生物浸出过程从人工污染的土壤中去除了98％的Co和96％的Cs，与对照样品相比，去除效率大约提高了一倍。这些结果表明，由硫氧化细菌进行的生物浸提具有作为放射性核素污染土壤的修复策略的潜力。