A spectroscopic study on U(VI) biomineralization in cultivated Pseudomonas fluorescens biofilms isolated from granitic aquifers

Krawczyk-Bärsch, Evelyn; Lütke, Laura; Moll, Henry; Bok, Frank; Steudtner, Robin; Roßberg, André

doi:10.1007/s11356-014-3671-4

Cited by 19 publications

(7 citation statements)

References 53 publications

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“…According to the TEM studies, uranium was mainly removed by bioaccumulation within the cytoplasm and bonded via protonated phosphoryl containing groups. The formation of meta-autunite, as a response of uranium interaction with microorganisms, was mentioned by few studies [ 19 , 80 , 81 ]. However, no study with R .…”

Section: Resultsmentioning

confidence: 99%

Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

et al. 2018

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Remediation of former uranium mining sites represents one of the biggest challenges worldwide that have to be solved in this century. During the last years, the search of alternative strategies involving environmentally sustainable treatments has started. Bioremediation, the use of microorganisms to clean up polluted sites in the environment, is considered one the best alternative. By means of culture-dependent methods, we isolated an indigenous yeast strain, KS5 (Rhodosporidium toruloides), directly from the flooding water of a former uranium mining site and investigated its interactions with uranium. Our results highlight distinct adaptive mechanisms towards high uranium concentrations on the one hand, and complex interaction mechanisms on the other. The cells of the strain KS5 exhibit high a uranium tolerance, being able to grow at 6 mM, and also a high ability to accumulate this radionuclide (350 mg uranium/g dry biomass, 48 h). The removal of uranium by KS5 displays a temperature- and cell viability-dependent process, indicating that metabolic activity could be involved. By STEM (scanning transmission electron microscopy) investigations, we observed that uranium was removed by two mechanisms, active bioaccumulation and inactive biosorption. This study highlights the potential of KS5 as a representative of indigenous species within the flooding water of a former uranium mine, which may play a key role in bioremediation of uranium contaminated sites.

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Section: Resultsmentioning

confidence: 99%

Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

et al. 2018

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“…The EXAFS structural parameters obtained from theoretical fitting are summarized in Table . The interatomic distances ( R ) of 1.78–1.79 Å calculated for U–O ax are typical of the uranyl(VI) arrangement (i.e., UO 2 2+ ) and also found for the uranyl(VI) complexes sorbed on biological substances. ,,− …”

Section: Resultsmentioning

confidence: 82%

Interaction of Uranium(VI) with α-Amylase and Its Implication for Enzyme Activity

Barkleit

Hennig

Ikeda‐Ohno

2018

Chem. Res. Toxicol.

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Because of its chemo- and radiotoxicity, the incorporation of uranium into human body via ingestion potentially poses a serious health risk. When ingested, the gastrointestinal fluids are the primary media to interact with uranium, eventually influencing and even determining its biochemical behavior in the gastrointestinal tract and thereafter. The chemical interactions between uranium and the components of gastrointestinal fluids are, however, poorly understood to date. In this study, the complexation of uranium(VI) (as the uranyl ion, UO) with the protein α-amylase, one of the major enzymes in saliva and pancreatic juices, was investigated over a wide range of pH or uranium/α-amylase concentrations covering physiological conditions. Macroscopic sorption experiments suggested a strong and fast complexation of UO to α-amylase between pH 5 and 7. Potentiometric titration was employed to determine the complex stability constants for the relevant UO α-amylase complexes, which is crucial for reliable thermochemical modeling to assess the potential health risk of uranium. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that α-amylase is interacting with UO primarily via its carboxylate groups presumably from the aspartic acid and glutamic acid side chains. The effect of UO on the enzyme activity was also investigated to understand the potential implication of uranium for the in vivo functions of the digestive fluids, indicating that the presence of uranium inhibits the enzyme activity. This inhibitory effect can be, however, suppressed by an excess of calcium.

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“…33 Uranium precipitates occurred due to phosphate release from the cellular polyphosphate, likely as a response of cells to added uranium. 21,34 By comparison, only small similar precipitants were observed on the surface of S. putrefaciens, when AQS ( Fig. 4(e and f)) and RF ( Fig.…”

Section: Analysis Of Uranium Speciationmentioning

confidence: 85%

Effects of riboflavin and AQS as electron shuttles on U(vi) reduction and precipitation byShewanella putrefaciens

et al. 2018

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A spectroscopic study on U(VI) biomineralization in cultivated Pseudomonas fluorescens biofilms isolated from granitic aquifers

Cited by 19 publications

References 53 publications

Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

Metabolism-dependent bioaccumulation of uranium by Rhodosporidium toruloides isolated from the flooding water of a former uranium mine

Interaction of Uranium(VI) with α-Amylase and Its Implication for Enzyme Activity

Effects of riboflavin and AQS as electron shuttles on U(vi) reduction and precipitation byShewanella putrefaciens

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