Actinide Binding and Solubilization by Microbial Siderophores

Brainard, James R.; Strietelmeier, Betty A.; Smith, Paul H.; Langston-Unkefer, Pat J.; Barr, Mary E.; Ryan, R. R.

doi:10.1524/ract.1992.5859.2.357

Cited by 110 publications

(87 citation statements)

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“…This shows that the buffer present was strong enough to prevent any change in pH which would cause discoloration. Discoloration was observed in both dyed agars with citric acid and DFO; both ligands can complex UO 2 2ϩ and Fe 3ϩ (2,36,45). These results prove that discoloration in the dyed agars is caused only by ligands that sequester the metal ion from the dye.…”

Section: Discussionmentioning

confidence: 54%

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Renshaw¹,

Halliday

Robson

et al. 2003

Appl Environ Microbiol

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An assay to detect UO 2 2؉ complexation was developed based on the chrome azurol S (CAS) assay for siderophores (B. Schwyn and J. B. Neilands, Anal. Biochem. 160:47-56, 1987) and was used to investigate the ability of fungal metabolites to complex actinides. In this assay the discoloration of two dyed agars (one containing a CAS-Fe 3؉ dye and the other containing a CAS-UO 2 2؉ dye) caused by ligands was quantified. The assay was tested by using the siderophore desferrioxamine B (DFO), and the results showed that there was a regular, reproducible relationship between discoloration and the amount of siderophore added. The ratio of the discoloration on the CAS-UO 2 2؉ agar to the discoloration on the CAS-Fe 3؉ agar was independent of the amount of siderophore added. A total of 113 fungi and yeasts were isolated from three soil samples taken from the Peak District National Park. The fungi were screened for the production of UO 2 2؉ chelators by using the CAS-based assay and were also tested specifically for hydroxamate siderophore production by using the hydroxamate siderophore auxotroph Aureobacterium flavescens JG-9. This organism is highly sensitive to the presence of hydroxamate siderophores. However, the CAS-based assay was found to be less sensitive than the A. flavescens JG-9 assay. No significant difference between the results for each site for the two tests was found. Three isolates were selected for further study and were identified as two Pencillium species and a Mucor species. Our results show that the new assay can be effectively used to screen fungi for the production of UO 2 2؉ chelating ligands. We suggest that hydroxamate siderophores can be produced by mucoraceous fungi.

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Section: Discussionmentioning

confidence: 54%

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Renshaw¹,

Halliday

Robson

et al. 2003

Appl Environ Microbiol

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“…The solubilization of Pu(IV) hydrous oxides by chelating ligands is generally not efficient (23,27). Several reports have investigated the solubilization of Pu(IV) hydrous oxides by chelating ligands, like EDTA, NTA, and natural siderophores (5,27). The results of these studies indicate that the solubilization can take up to several months to reach equilibrium, and the total concentrations of Pu solubilized from Pu(IV) hydrous oxides are usually in the order of micromoles of Pu solubilized per gram of solid (27).…”

Section: Discussionmentioning

confidence: 99%

Plutonium(IV) Reduction by the Metal-Reducing Bacteria Geobacter metallireducens GS15 and Shewanella oneidensis MR1

Boukhalfa

Icopini

Reilly

et al. 2007

Appl Environ Microbiol

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The bacterial reduction of actinides has been suggested as a possible remedial strategy for actinide-contaminated environments, and the bacterial reduction of Pu(VI/V) has the potential to produce highly insoluble Pu(IV) solid phases. However, the behavior of plutonium with regard to bacterial reduction is more complex than for other actinides because it is possible for Pu(IV) to be further reduced to Pu(III), which is relatively more soluble than Pu(IV). This work investigates the ability of the metal-reducing bacteria Geobacter metallireducens GS15 and Shewanella oneidensis MR1 to enzymatically reduce freshly precipitated amorphous Pu(IV) (OH)4 [Pu(IV)(OH)4(am)] and soluble Pu(IV)(EDTA). In cell suspensions without added complexing ligands, minor Pu(III) production was observed in cultures containing S. oneidensis, but little or no Pu(III) production was observed in cultures containing G. metallireducens. In the presence of EDTA, most of the Pu(IV)(OH)4(am) present was reduced to Pu(III) and remained soluble in cell suspensions of both S. oneidensis and G. metallireducens. When soluble Pu(IV)(EDTA) was provided as the terminal electron acceptor, cell suspensions of both S. oneidensis and G. metallireducens rapidly reduced Pu(IV)(EDTA) to Pu(III)(EDTA) with nearly complete reduction within 20 to 40 min, depending on the initial concentration. Neither bacterium was able to use Pu(IV) (in any of the forms used) as a terminal electron acceptor to support growth. These results have significant implications for the potential remediation of plutonium and suggest that strongly reducing environments where complexing ligands are present may produce soluble forms of reduced Pu species.

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“…To explore this possibility, some of our experiments included adsorbed Pb(II) as a typical hazardous trace metal whose surface complexation reactions with goethite have been investigated extensively (e.g., Müller and Sigg, 1992;Rodda et al, 1993;Gunneriusson et al, 1994;Bargar et al, 1997), and for which formation constants of Pb(II)-desferrioxamine B complexes in aqueous solution are available . Our new results, pertaining to the effect of a hydroxamate siderophore on adsorbed Pb(II), are relevant to hazardous metal waste recovery and remediation in soils (Brainard et al, 1992).…”

Section: Introductionmentioning

confidence: 89%

Effect of hydroxamate siderophores on Fe release and Pb(II) adsorption by goethite

Kraemer

Cheah

Zapf

et al. 1999

Geochimica et Cosmochimica Acta

126

107

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Abstract-Hydroxamate siderophores are biologically-synthesized, Fe(III)-specific ligands which are common in soil environments. In this paper, we report an investigation of their adsorption by the iron oxyhydroxide, goethite; their influence on goethite dissolution kinetics; and their ability to affect Pb(II) adsorption by the goethite surface. The siderophores used were desferrioxamine B (DFO-B), a fungal siderophore, and desferrioxamine D 1 , an acetyl derivative of DFO-B (DFO-D1). Siderophore adsorption isotherms yielded maximum surface concentrations of 1.5 (DFO-B) or 3.5 (DFO-D1) mol/g at pH 6.6, whereas adsorption envelopes showed either cation-like (DFO-B) or ligand-like (DFO-D1) behavior. Above pH 8, the adsorbed concentrations of both siderophores were similar. The dissolution rate of goethite in the presence of 240 M DFO-B or DFO-D1 was 0.02 or 0.17 mol/g hr, respectively. Comparison of these results with related literature data on the reactions between goethite and acetohydroxamic acid, a monohydroxamate ligand, suggested that the three hydroxamate groups in DFO-D1 coordinate to Fe(III) surface sites relatively independently. The results also demonstrated a significant depleting effect of 240 M DFO-B or DFO-D1 on Pb(II) adsorption by goethite at pH Ͼ 6.5, but there was no effect of adsorbed Pb(II) on the goethite dissolution rate.

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Actinide Binding and Solubilization by Microbial Siderophores

Cited by 110 publications

References 0 publications

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Plutonium(IV) Reduction by the Metal-Reducing Bacteria Geobacter metallireducens GS15 and Shewanella oneidensis MR1

Effect of hydroxamate siderophores on Fe release and Pb(II) adsorption by goethite

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