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

Frontiers in Microbiology

Microbiology

A. Schippers¹  S. Weyer²  Y. Roebbert²  C. D. Rosendahl² 

[1] Federal Institute for Geosciences and Natural Resources (BGR), Geomicrobiology, Hannover, Germany;Leibniz Universität Hannover, Institut für Mineralogie, Hannover, Germany;

关键词: uranium;    isotope fractionation;    remobilization;    laboratory batch experiments;    Thiobacillus denitrificans;    Acidithiobacillus ferrooxidans;   

DOI  :  10.3389/fmicb.2023.1190962

 received in 2023-03-21, accepted in 2023-06-28,  发布年份 2023

来源: Frontiers

【 摘 要 】

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

【 授权许可】

Unknown   
Copyright © 2023 Rosendahl, Roebbert, Schippers and Weyer.

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