Reduction of Cr, Mo, Se and U by Desulfovibrio desulfuricans immobilized in polyacrylamide gels

Tucker, Mark; Barton, Larry L.; Thomson, Bruce M.

doi:10.1038/sj.jim.2900472

Cited by 125 publications

(69 citation statements)

References 14 publications

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“…(g.h) -1 [22]. Pseudomonas fluorescens only reduced 95% of 0.2 mM selenate after 45 hours [23] and Desulvibrio desulfuricans took 25-37 hours to reduce 86% of 1 mM of selenate [24] which is much slower than what was observed in this study.…”

Section: Reduction Rate Experimentscontrasting

confidence: 55%

Reduction of Selenium by Pseudomonas stutzeri Nt-I: Growth, Reduction and Kinetics

Ce¹,

Emn²

2017

J Bioremediat Biodegrad

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IntroductionSelenium, first discovered in 1818, is a metalloid and chalcogen. It has multiple oxidation states, beginning with the most reduced state, namely selenate (SeO 4 2-, Se(VI)), followed by selenite (SeO 3 2-, Se(IV)), elemental selenium (Se 0 , Se(0)) and finally selenide (Se 2-). Of the selenium released into the environment, 37.5-40.6% can be ascribed to anthropogenic activities. It is released from the earth's crust by the mining of coal and various metals, oil production, use of agricultural products, as well as during the melting of non-ferrous metals [1]. Landfill ash disposal that generates toxic leachate poses a risk of groundwater contamination, which leads to the polluting of nearby water bodies [2].Selenium is mostly present in water as selenate or selenite. According to different studies, acid mine drainage waters contain selenium at concentrations ranging between 2 × 10 -4 and 6.2 × 10 -3 mM of total selenium [3]. Waste water from oil refineries in the San Francisco Bay (USA) contains relatively low concentrations of selenium of about 50-300 µg. L -1 [4]. The waste water from a selenium refinery plant in Japan contained an average of 30 mg. L -1 selenium, with the majority of the selenium present as selenite [4].The upward trend in energy production from coal, along with the burning of fossil fuels contribute to this increase in selenium release. The high concentration of these selenium oxyanions poses a problem to the environment, since they are toxic and bio-accumulate readily. In one case it was found the concentration of selenium in the apex predators (birds and humans) in the area were 2 000 times higher than in the water [4]. Elemental selenium is not soluble in water and thus has a much lower bio-availability than the oxyanions. Elemental selenium's toxicity is also much lower than that of the oxyanions [1]. AbstractBioremediation of seleniferous water is gaining more momentum, especially when it comes to bacterial reduction of the selenium oxyanions. More and more bacterial strains that are able to reduce selenium are being isolated. These bacteria need to be studied further to determine whether they are suited for industrial application. In this study, the reduction of Se(VI) to Se(0) by Pseudomonas stutzeri NT-I was examined using batch experiments with the bacteria suspended in MSM. For the determination of the optimum conditions for the growth of the bacteria, the linearized rate during the exponential phase for different conditions were compared. A pH 7, temperature of 37°C, salinity of 20 g.L -1 NaCl and initial concentration of 5 mM selenate were found to be the best at promoting growth. To determine the optimum conditions for the reduction of selenium, the amount of Se (0) recovered from the plug after 16 hours of incubation was measured. A pH of 8, temperature of 37°C and salinity of 5 g.L -1 resulted in the most Se (0) recovered. The kinetics of the reduction of Se(VI) to Se (0) was found to follow the adapted Monod equation. An increase in the initial Se(VI) concentrati...

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Section: Reduction Rate Experimentscontrasting

confidence: 55%

Reduction of Selenium by Pseudomonas stutzeri Nt-I: Growth, Reduction and Kinetics

Ce¹,

Emn²

2017

J Bioremediat Biodegrad

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“…As an example, Figure S3 shows the dynamics of Desulfovibrio vulgaris, Geobacter metallireducens, and methanogenic archaea in water samples. The occurrence of these bacteria and archaea suggest a possibility of both direct enzymatically mediated microbial Cr(VI) reduction and an indirect Cr(VI) reduction through byproducts of microbial metabolism such as Fe 2+ and reactive sulfides (21,22,38,39).…”

Section: Resultsmentioning

confidence: 99%

“…(In this paper we characterize the microbial biomass using the total number of bacteria, which was determined using direct microscopy after acridine orange staining-AODC.) Although many bacterial strains are known to enhance reduction of Cr(VI) to Cr(III) both aerobically (17,18) and anaerobically (19)(20)(21)(22), only a few studies have examined the in situ potential of Cr(VI) microbial reduction in subsurface materials (e.g., [23][24][25]. Laboratory studies have also shown that Cr(VI) reduction in saturated soil aggregates under anaerobic conditions is mainly diffusion-rate-limited and can be strongly transport-controlled and localized (26,27).…”

Section: +mentioning

confidence: 99%

In Situ Long-Term Reductive Bioimmobilization of Cr(VI) in Groundwater Using Hydrogen Release Compound

Faybishenko

Hazen

Long

et al. 2008

Environ. Sci. Technol.

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“…Many strains have been isolated that sorb (14,23,51,59,61), reduce (10,18,52,56), and precipitate (4,33,41,44,45) metals, usually on the outer membrane of the cell. Sorption is generally achieved in a reversible process and is dependent on the composition of the water being treated, as other chelating agents compete with the complexing moieties on the cell.…”

mentioning

confidence: 99%

Uranyl Precipitation byPseudomonas aeruginosavia Controlled Polyphosphate Metabolism

Renninger¹,

Knopp²,

Nitsche

et al. 2004

Appl Environ Microbiol

108

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The polyphosphate kinase gene from Pseudomonas aeruginosa was overexpressed in its native host, resulting in the accumulation of 100 times the polyphosphate seen with control strains. Degradation of this polyphosphate was induced by carbon starvation conditions, resulting in phosphate release into the medium. The mechanism of polyphosphate degradation is not clearly understood, but it appears to be associated with glycogen degradation. Upon suspension of the cells in 1 mM uranyl nitrate, nearly all polyphosphate that had accumulated was degraded within 48 h, resulting in the removal of nearly 80% of the uranyl ion and >95% of lesser-concentrated solutions. Electron microscopy, energy-dispersive X-ray spectroscopy, and time-resolved laser-induced fluorescence spectroscopy (TRLFS) suggest that this removal was due to the precipitation of uranyl phosphate at the cell membrane. TRLFS also indicated that uranyl was initially sorbed to the cell as uranyl hydroxide and was then precipitated as uranyl phosphate as phosphate was released from the cell. Lethal doses of radiation did not halt phosphate secretion from polyphosphate-filled cells under carbon starvation conditions.Biological methods for the removal of heavy metals and actinides have recently been investigated due to their cost effectiveness at moderate metal concentrations. Many strains have been isolated that sorb (14,23,51,59,61), reduce (10, 18, 52, 56), and precipitate (4, 33, 41, 44, 45) metals, usually on the outer membrane of the cell. Sorption is generally achieved in a reversible process and is dependent on the composition of the water being treated, as other chelating agents compete with the complexing moieties on the cell. Thus, the applicability of this method in more complex waste streams or environments may be somewhat suspect due to the relatively low binding affinities of cellular components for metals compared to chelators, such as humic or organic acids. Reduction is generally limited to anaerobic processes and is ineffective against single-oxidationstate metals. Precipitation has the advantage of producing chemically stable forms of metal, and its use is not limited to reducible metals.With respect to the biological precipitation of metals, both metal sulfides (12,57,58,60) and metal phosphates (4, 33, 45) have been investigated due to their low solubilities. While some work has been done to produce sulfide aerobically (57), its production is generally an anaerobic process, limiting its applicability. The release of phosphate via the hydrolysis of an organic phosphate has been shown to be an effective method for the precipitation of metals on cell membranes. Macaskie and Dean (30) isolated a cadmium-resistant strain of Citrobacter that precipitated numerous metals, such as uranyl ion, as metal phosphates through the use of a membranebound acid phosphatase (26,31,32). Using glycerol-2-phosphate as a phosphate source, the organism cleaved phosphate from the source in the periplasmic space, leaving it to bind with metals that had been complexe...

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Reduction of Cr, Mo, Se and U by Desulfovibrio desulfuricans immobilized in polyacrylamide gels

Cited by 125 publications

References 14 publications

Reduction of Selenium by Pseudomonas stutzeri Nt-I: Growth, Reduction and Kinetics

Reduction of Selenium by Pseudomonas stutzeri Nt-I: Growth, Reduction and Kinetics

In Situ Long-Term Reductive Bioimmobilization of Cr(VI) in Groundwater Using Hydrogen Release Compound

Uranyl Precipitation byPseudomonas aeruginosavia Controlled Polyphosphate Metabolism

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