U mobilization and associated U isotope fractionation by sulfur-oxidizing bacteria

Uranium (U) contamination of the environment causes high risk to health, demanding for effective and sustainable remediation. Bioremediation via microbial reduction soluble U(VI) is generating fractions (>50%) insoluble non-crystalline U(IV) which, however, might be remobilized by sulfur-oxidizing bacteria. In this study, efficacy Acidithiobacillus (At.) ferrooxidans Thiobacillus (T.) denitrificans mobilize associated U isotope fractionation were investigated. At. mobilized between 74 91% after 1 week, mobilization was observed both, living inactive cells. Contrary previous observations, no T. could observed. did not cause suggesting that ratio determination unsuitable as a direct proxy bacterial remobilization. The similar capability active cells suggests based on reaction with cell biomass. This study raises doubts about long-term sustainability in-situ bioremediation measures at U-contaminated sites, especially regard being main component bioremediation.