Effect of culture medium ions on chromate reduction by resting cells of Agrobacterium radiobacter

Llovera, S; Bonet, Ramon; Simon-Pujol, Maria Dolores; Congregado, Francisco

doi:10.1007/bf00192105

Cited by 33 publications

(28 citation statements)

References 11 publications

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“…Under this conditions, other electron acceptors such as nitrate or metal ions such as manganese or iron would be used as an alternative (Haley et al, 2012). Resting cells have been used in studying heavy metals reduction such as in selenate (Losi and Jr, 1997), vanadate (Carpentier et al, 2005), chromate (Llovera et al, 1993), reductions and xenobiotics biodegradation such as phenol (Sedighi and Vahabzadeh, 2014), amides (Raj et al, 2010), diesel (Auffret et al, 2015), SDS (Chaturvedi and Kumar, 2011), and pentachlorophenol (Steiert et al, 1987).…”

Section: Identification Of Molybdenum-reducing Bacteriummentioning

confidence: 99%

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND GLYPHOSATE-DEGRADING Klebsiella oxytoca STRAIN SAW-5 IN SOILS FROM SARAWAK

et al. 2016

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Bioremediation of pollutants including heavy metals and xenobiotics is an economic and environmentally friendly process. A novel molybdenum-reducing bacterium with the ability to utilize the pesticide glyphosate as a carbon source is reported. The characterization works were carried out utilizing bacterial resting cells in a microplate format. The bacterium reduces molybdate to Mo-blue optimally between pH 6.3 and 6.8 and at 34 o C. Glucose was the best electron donor for supporting molybdate reduction followed by lactose, maltose, melibiose, raffinose, d-mannitol, d-xylose, l-rhamnose, l-arabinose, dulcitol, myo-inositol and glycerol in descending order. Other requirements include a phosphate concentration at 5.0 mM and a molybdate concentration between 20 and 30 mM. The molybdenum blue exhibited an absorption spectrum resembling a reduced phosphomolybdate. Molybdenum reduction was inhibited by mercury, silver, cadmium and copper at 2 ppm by 45.5, 26.0, 18.5 and 16.3%, respectively. Biochemical analysis identified the bacterium as Klebsiella oxytoca strain Saw-5. To conclude, the capacity of this bacterium to reduce molybdenum into a less toxic form and to grow on glyphosate is novel and makes the bacterium an important instrument for bioremediation of these pollutants.

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Section: Identification Of Molybdenum-reducing Bacteriummentioning

confidence: 99%

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND GLYPHOSATE-DEGRADING Klebsiella oxytoca STRAIN SAW-5 IN SOILS FROM SARAWAK

et al. 2016

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“…This approach is taken in the bioremediation of Cr(VI) pollution. It shows promise for solving pollution problems and has advantages over various other physical and chemical methods.Chromate-reducing activities can be found in the cell extracts of many bacteria (4,5,8,10,13,18,25,30,(33)(34)(35). Chromate reductase can reduce the toxicity of Cr(VI) by reducing it to Cr(III) and lowering its solubility (5, 9).…”

mentioning

confidence: 99%

Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

Kwak

Lee

Kim

2003

Appl Environ Microbiol

144

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The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5␣ and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione Stransferase (GST) and E. coli DH5␣ NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5␣ NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared for their overproduction and easy purification. GST-EcNfsA, GST-EcNFsB, and GST-VhNFsA efficiently reduced nitrofurazone and 2,4,6-trinitrotoluene (TNT) as their nitro substrates. The K m values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 11.8, 23.5, and 5.4 M, respectively. The V max values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA were 3.8, 3.9, and 10.7 nmol/min/mg of protein, respectively. GST-VhNfsA was the most effective of the three chromate reductases, as determined by each V max /K m value. The optimal temperatures of GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 55, 30, and 30°C, respectively. Thus, it is confirmed that nitroreductase can also act as a chromate reductase. Nitroreductases may be used in chromate remediation. GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA have a molecular mass of 50 kDa and exist as a monomer in solution. Thin-layer chromatography showed that GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA contain FMN as a cofactor. GST-VhNfsA reduced Cr(VI) to Cr(III). Cr(III) was much less toxic to E. coli than Cr(VI).Environmental pollution by chromium may be severe. Chromium contamination is known to be prevalent at U.S. Department of Energy sites (29). The electroplating and leather-tanning industries also contribute to environmental contamination with Cr(VI) (23). Chromate compounds containing Cr(VI) are used widely in the cooling towers of heavy industry and atomic power plants, since Cr(VI) prevents corrosion and the growth of organisms (2). Cr(VI) is soluble, toxic, and carcinogenic, whereas Cr(III) is less soluble and less toxic (12). Thus, it is desirable to change Cr(VI) into Cr(III). This approach is taken in the bioremediation of Cr(VI) pollution. It shows promise for solving pollution problems and has advantages over various other physical and chemical methods.Chromate-reducing activities can be found in the cell extracts of many bacteria (4,5,8,10,13,18,25,30,(33)(34)(35). Chromate reductase can reduce the toxicity of Cr(VI) by reducing it to Cr(III) and lowering its solubility (5, 9). The chromate reductase from Pseudomonas ambigua has been purified and characterized (33). Chromate-reducing activities have been associated with DT-diaphorase (7) and aldehyde oxidase (1) in the cell cytoplasm. Cytochrome P450 located in the cell membrane is also known to have chromate-reducing activity (21). It seems that various reductases in the cell can function in chromate reduction. P. ambigua chromate reductase (33) has high homology with Escherichia coli NfsA (59%) ...

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“…The use of resting cells for studying Mo-blue production was initiated in EC 48 (Ghani et al 1993). Resting cells were also used in studying heavy metals reduction such as in chromate (Llovera et al 1993), selenate (Losi & Jr 1997) and xenobiotics biodegradation such as diesel (Auffret et al 2015) and phenol (Sedighi & Vahabzadeh 2014).…”

Section: Discussionmentioning

confidence: 99%

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND PHENOLIC- AND CATECHOL-DEGRADING Enterobacter sp. STRAIN SAW-2

Sabullah

Rahman²,

Ahmad³

et al. 2017

BIOTROPIA

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Molybdenum is an emerging pollutant worldwide. The objective of this study is to isolate molybdenum-reducing bacterium with the ability to grow on phenolic compounds (phenol and catechol). The screening process was carried out on a microplate. The bacterium reduced molybdenum in the form of sodium molybdate to molybdenum blue (Mo-blue). The bacterium required a narrow pH range for optimal reduction of molybdenum, i.e. between pH 6.3 and o 6.8, with temperature between 34 and 37 C. Molybdate reduction to Mo-blue was best supported by glucose as the carbon source. However, both phenol and catechol could not support molybdate reduction. Other requirements for molybdate reduction included sodium molybdate concentrations between 15 and 30 mM, and phosphate concentration of 5.0 mM. The bacterium exhibited a Mo-blue absorption spectrum with a shoulder at 700 nm and a maximum peak near the infrared region at 865 nm. The Mo-reducing bacterium was partially identified as Enterobacter sp. strain Saw-2. The capability of this bacterium to grow on toxic phenolic compounds and to detoxify molybdenum made it a significant agent for bioremediation.

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Effect of culture medium ions on chromate reduction by resting cells of Agrobacterium radiobacter

Cited by 33 publications

References 11 publications

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND GLYPHOSATE-DEGRADING Klebsiella oxytoca STRAIN SAW-5 IN SOILS FROM SARAWAK

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND GLYPHOSATE-DEGRADING Klebsiella oxytoca STRAIN SAW-5 IN SOILS FROM SARAWAK

Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND PHENOLIC- AND CATECHOL-DEGRADING Enterobacter sp. STRAIN SAW-2

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