Combined use of flow cytometry and microscopy to study the interactions between the gram-negative betaproteobacterium Acidovorax facilis and uranium(VI).
The former uranium mine Königstein (Saxony, Germany) is currently in the process of remediation by means of controlled underground flooding. Nevertheless, the flooding water has to be cleaned up by a conventional wastewater treatment plant. In this study, the uranium(VI) removal and tolerance mechanisms of the gram-negative betaproteobacterium Acidovorax facilis were investigated by a multidisciplinary approach combining wet chemistry, flow cytometry, and microscopy. The kinetics of uranium removal and the corresponding mechanisms were investigated. The results showed a biphasic process of uranium removal characterized by a first phase where 95% of uranium was removed within the first 8h followed by a second phase that reached equilibrium after 24h. The bacterial cells displayed a total uranium removal capacity of 130mgU/g dry biomass. The removal of uranium was also temperature-dependent, indicating that metabolic activity heavily influenced bacterial interactions with uranium. TEM analyses showed biosorption on the cell surface and intracellular accumulation of uranium. Uranium tolerance tests showed that A. facilis was able to withstand concentrations up to 0.1mM. This work demonstrates that A. facilis is a suitable candidate for in situ bioremediation of flooding water in Königstein as well as for other contaminated waste waters.
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, P.O. Box 510119, 01314 Dresden, Germany. Electronic address: u.gerber@hzdr.de.
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U
Gerber
Research Institute of Leather and Plastic Sheeting (FILK) gGmbH, Meissner Ring 1-5, 09599 Freiberg, Germany.
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Zirnstein
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, P.O. Box 510119, 01314 Dresden, Germany.
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Krawczyk-Bärsch
Helmholtz Centre for Infection Research, Central Facility for Microscopy, Inhoffenstr. 7, D-38124 Braunschweig, Germany.
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Lünsdorf
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, P.O. Box 510119, 01314 Dresden, Germany.
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T
Arnold
University of Granada, Department of Microbiology, Campus Fuentenueva, E-18071 Granada, Spain.
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Merroun
D000327:Adsorption; D001673:Biodegradation, Environmental; D018533:Biomass; D042621:Comamonadaceae / Q000187:drug effects / Q000254:growth & development*; D005434:Flow Cytometry; D005858:Germany; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008906:Mining; D017974:Uranium Compounds / Q000032:analysis*; D062065:Wastewater / Q000737:chemistry; D014875:Water Pollutants, Radioactive / Q000032:analysis*
D017974:Uranium Compounds; D062065:Wastewater; D014875:Water Pollutants, Radioactive
AMD; Acidovorax facilis; Flow cytometry; In situ bioremediation; Metal tolerance; Uranium