A Desulfovibrio sp. capable of growing by reducing U(VI)

Pietzsch, Katja; Hard, Barbara C.; Babel, Wolfgang

doi:10.1002/(sici)1521-4028(199912)39:5/6<365::aid-jobm365>3.3.co;2-3

Cited by 12 publications

(17 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(33,34,40). Some of these microorganisms have been reported to conserve energy for growth from U(VI) reduction (29,40,47), while others reduce uranium without apparent energy gain (4,12,21,23,33,34,44,46).…”

mentioning

confidence: 99%

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

Wu¹,

Sanford

Löffler

2006

Appl Environ Microbiol

121

View full text Add to dashboard Cite

Previous studies demonstrated growth of Anaeromyxobacter dehalogenans strain 2CP-C with acetate or hydrogen as the electron donor and Fe(III), nitrate, nitrite, fumarate, oxygen, or ortho-substituted halophenols as electron acceptors. In this study, we explored and characterized U(VI) reduction by strain 2CP-C. Cell suspensions of fumarate-grown 2CP-C cells reduced U(VI) to U(IV). More-detailed growth studies demonstrated that hydrogen was the required electron donor for U(VI) reduction and could not be replaced by acetate. The addition of nitrate to U(VI)-reducing cultures resulted in a transitory increase in U(VI) concentration, apparently caused by the reoxidation of reduced U(IV), but U(VI) reduction resumed following the consumption of N-oxyanions. Inhibition of U(VI) reduction occurred in cultures amended with Fe(III) citrate, or citrate. In the presence of amorphous Fe(III) oxide, U(VI) reduction proceeded to completion but the U(VI) reduction rates decreased threefold compared to control cultures. Fumarate and 2-chlorophenol had no inhibitory effects on U(VI) reduction, and both electron acceptors were consumed concomitantly with U(VI). Since cocontaminants (e.g., nitrate, halogenated compounds) and bioavailable ferric iron are often encountered at uranium-impacted sites, the metabolic versatility makes Anaeromyxobacter dehalogenans a promising model organism for studying the complex interaction of multiple electron acceptors in U(VI) reduction and immobilization.

show abstract

mentioning

confidence: 99%

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

Wu¹,

Sanford

Löffler

2006

Appl Environ Microbiol

121

View full text Add to dashboard Cite

show abstract

“…Microorganisms that reduce U(VI) in pure culture include a hyperthermophilic archaeon (15), a thermophilic bacterium (19), mesophilic Fe(III)-and sulfatereducing bacteria (4,5,34,25,27,28), and fermentative bacteria (9). Thus, the ability to reduce U(VI) occurs in phylogenetically diverse organisms.…”

mentioning

confidence: 99%

Microbial Populations Stimulated for Hexavalent Uranium Reduction in Uranium Mine Sediment

Suzuki

Kelly

Kemner

et al. 2003

Appl Environ Microbiol

179

108

View full text Add to dashboard Cite

Uranium-contaminated sediment and water collected from an inactive uranium mine were incubated anaerobically with organic substrates. Stimulated microbial populations removed U almost entirely from solution within 1 month. X-ray absorption near-edge structure analysis showed that U(VI) was reduced to U(IV) during the incubation. Observations by transmission electron microscopy, selected area diffraction pattern analysis, and energy-dispersive X-ray spectroscopic analysis showed two distinct types of prokaryotic cells that precipitated only a U(IV) mineral uraninite (UO 2 ) or both uraninite and metal sulfides. Prokaryotic cells associated with uraninite and metal sulfides were inferred to be sulfate-reducing bacteria. Phylogenetic analysis of 16S ribosomal DNA obtained from the original and incubated sediments revealed that microbial populations were changed from microaerophilic Proteobacteria to anaerobic low-G؉C gram-positive sporeforming bacteria by the incubation. Forty-two out of 94 clones from the incubated sediment were related to sulfate-reducing Desulfosporosinus spp., and 23 were related to fermentative Clostridium spp. The results suggest that, if in situ bioremediation were attempted in the uranium mine ponds, Desulfosporosinus spp. would be a major contributor to U(VI) and sulfate reduction and Clostridium spp. to U(VI) reduction.Uranium-bearing wastes from nuclear weapons production (22) and mining (31) have generally been disposed of in nearsurface environments. Dispersion of toxic aqueous uranium species through groundwater is of great environmental concern (30). In situ stimulation of the growth of microorganisms capable of immobilizing dissolved uranium has been proposed as a potentially cost-effective remediation method (23,24).In the laboratory, it has been demonstrated that microorganisms can reduce hexavalent uranium [U(VI)] to tetravalent uranium [U(IV)] and precipitate a U(IV) mineral called uraninite (UO 2 ) (27,40). Microorganisms that reduce U(VI) in pure culture include a hyperthermophilic archaeon (15), a thermophilic bacterium (19), mesophilic Fe(III)-and sulfatereducing bacteria (4,5,34,25,27,28), and fermentative bacteria (9). Thus, the ability to reduce U(VI) occurs in phylogenetically diverse organisms. In laboratory studies, U(VI) is also reduced by microbes in solutions that contain organic or inorganic ligands or other cations (13,26,33) or that contain other electron acceptors such as Fe(III) oxides, sulfate, or selenate (12,24,40,45).Microbial U(VI) reduction in uranium-contaminated settings has been studied by incubating field-collected sediment and water with organic substrates to stimulate the growth of indigenous microorganisms in the laboratory (1, 2, 15). Although previous studies showed uranium removal from solution during laboratory incubation, the mechanisms by which uranium was removed from solution and the microbial species responsible remain unclear.In this study, we attempted to better understand the bioremediation process through integration of results obtaine...

show abstract

“…As shown in Figure 2, more than 25 species of phylogenetically diverse prokaryotes are known to mediate enzymatic U(VI) reduction, including a hyperthermophilic archaeon (Kashefi and Lovley, 2000), thermophilic bacteria (Kieft et al, 1999), mesophilic Fe(III) reducing bacteria (Lovley et al, 1991, Coates et al, 1998Coates et al, 2001), mesophilic sulfate reducing bacteria (Lovley and Phillips, 1992;Lovley et al, 1993;Tebo and Obraztsova, 1998;Suzuki et al, 2005), fermentative bacteria (Francis et al, 1994;Sani et al, 2002), a heterotrophic bacterium (McLean and Beveridge, 2001), and an acidotolerant bacterium (Shelobolina et al, 2004). Some of these have been shown to grow using U(VI) as a sole terminal electron acceptor (Lovley et al, 1991;Tebo and Obraztsova, 1998;Pietzsch et al, 1999). Considering the overwhelming number of Fe(III) reducing bacteria, many of which have not been examined for their U(VI) reduction abilities, there may be many more U(VI) reducing bacteria than are currently known.…”

Section: Direct Enzymatic Control Of the Redox Transformations Of Umentioning

confidence: 99%

Geomicrobiological factors that control uranium mobility in the environment: Update on recent advances in the bioremediation of uranium-contaminated sites

Suzuki

Suko

2006

Journal of Mineralogical and Petrological Sciences

View full text Add to dashboard Cite

Understanding the behavior of uranium (U) in the environment is essential not only for the protection of aquifers from U contamination but also for predicting the fate of U and other actinides disposed of in deep geological settings. It has long been believed that the redox chemistry of U can be simply predicted by thermodynamics and that the development of a low redox potential is a sufficient condition for U reduction. However, recent studies have demonstrated that redox transformations of U are controlled by kinetic factors that are strongly influenced by microbial activity. Although abiological U oxidation proceeds efficiently under oxygenic conditions, abiological reduction of U is inhibited by the formation of negatively charged U(VI) CO 3 complexes that prevail in nature. Phylogenetically diverse microorganisms are capable of enzymatically reducing U(VI) CO 3 complexes to form U(IV) bearing minerals such as uraninite (UO 2+x ). The only abiological pathway currently known for the reduction of U(VI) CO 3 complexes involves the Fe(II) monohydroxo surface complex Fe III OFe II OH 0 . This complex is mainly produced by the microbial reduction of Fe(III) in natural systems. Thus, U(VI) reduction is controlled both directly and indirectly, at least in part, by microbial activity. Several mechanisms of U oxidation under anoxic conditions have been revealed recently by laboratory and field studies. U(IV) is abiologically oxidized by Fe(III) and Mn(IV) oxides. Microbial reduction of nitrate to molecular nitrogen, which occurs following the depletion of O 2 , produces nitrogen intermediates including nitrite (NO 2 -), nitrous oxide (NO), and nitric oxide (N 2 O). Although the nitrogen intermediates oxidize U(IV), poorly crystalline Fe(III) oxide minerals resulting from the oxidation of aqueous Fe(II) species by the nitrogen intermediates oxidize U(IV) more efficiently than the nitrogen intermediates alone. Remarkably, the formation of Ca U(VI) CO 3 complexes resulting from increased levels of Ca 2+ and/or HCO 3 -leads to the reoxidation of bioreduced U(IV) under reducing conditions. These geomicrobiological factors pose challenges in manipulating and/or predicting the mobility and fate of U in complex and heterogeneous environmental settings.

show abstract

A Desulfovibrio sp. capable of growing by reducing U(VI)

Cited by 12 publications

References 11 publications

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

Microbial Populations Stimulated for Hexavalent Uranium Reduction in Uranium Mine Sediment

Geomicrobiological factors that control uranium mobility in the environment: Update on recent advances in the bioremediation of uranium-contaminated sites

Contact Info

Product

Resources

About