In vitro reduction of hexavalent chromium by a cell-free extract of Bacillus sp. ES 29 stimulated by Cu 2+

Camargo, Flávio Anastácio de Oliveira; Okeke, Benedict C.; Bento, Fátima Menezes; Frankenberger, W. T.

doi:10.1007/s00253-003-1291-x

Cited by 148 publications

(116 citation statements)

References 17 publications

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“…We therefore presume that chromate reductase is a membrane-bound enzyme in both isolates and is also secreted in the extracellular environment. Camargo et al [13] observed chromate reductase activity in the cell-free extract and soluble fraction but very low activity in the membrane fraction of Bacillus sp. ES29.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that Bacillus Sp. ES29 reduced 90% of Cr(VI) added (2 mg/l) to the medium in less than 6 h [13]. Thacker and Madamwar [14] have shown that the bacterial isolate DM1 reduces 50 ppm of chromium to 0 ppm in 54 h. They added a second aliquot of chromium which was reduced to 0 ppm in 99 h, and the third aliquot was reduced to 21.8 ppm in 126 h.…”

Section: Resultsmentioning

confidence: 99%

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Isolation and Characterization of Chromium(VI)-Reducing Bacteria from Tannery Effluents

et al. 2011

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Two chromium-resistant bacteria (IFR-2 and IFR-3) capable of reducing/transforming Cr(VI) to Cr(III) were isolated from tannery effluents. Isolates IFR-2 and IFR-3 were identified as Staphylococcus aureus and Pediococcus pentosaceus respectively by 16S rRNA gene sequence analyses. Both isolates can grow well on 2,000 mg/l Cr(VI) (as K 2 Cr 2 O 7 ) in Luria-Bertani (LB) medium. Reduction of Cr(VI) was found to be growthassociated in both isolates and IFR-2 and IFR-3 reduced 20 mg/l Cr(VI) completely in 6 and 24 h respectively. The Cr(VI) reduction due to chromate reductase activity was detected in the culture supernatant and cell lysate but not at all in the cell extract supernatant of both isolates. Whole cells of IFR-2 and IFR-3 converted 24 and 30% of the initial Cr(VI) concentration (1 mg/l) in 45 min respectively at 37°C. NiCl 2 stimulated the growth of IFR-2 whereas HgCl 2 and CdCl 2 significantly inhibited the growth of both isolates. Optimum temperature and pH for growth of and Cr(VI) reduction by both isolates were found to be between 35 and 40°C and pH 7.0 to 8.0. The two bacterial isolates can be good candidates for detoxification of Cr(VI) in industrial effluents.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Isolation and Characterization of Chromium(VI)-Reducing Bacteria from Tannery Effluents

et al. 2011

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“…Park et al [13] had demonstrated that Pseudomonas putida culture was able to carry out enzymatic reduction of chromates. Cr(VI) was also shown to be quantitatively transformed to Cr(III) largely by soluble reductase activities in Bacillus species isolated from chromium-contaminated soil samples [5] Chromium reduction by the Bacillus species was not affected by sulphate and/or nitrate. The removal of chromium ions by the cyanobacterium, Anacystis nidulans immobilised on agar has been documented [3] Reports on chromate reduction by resting cells of sulphate-reducing bacteria particularly, Desulfovibrio vulgaris [17] and Cellulomonas sp.…”

Section: Introductionmentioning

confidence: 92%

“…Many species of bacteria [1,[3][4][5][6][7][8], yeasts [9][10][11] and fungi [12][13][14][15][16] have been investigated from this aspect, and the biosorption and bioaccumulation of chromium for bioremediation purposes have been demonstrated. Park et al [13] had demonstrated that Pseudomonas putida culture was able to carry out enzymatic reduction of chromates.…”

Section: Introductionmentioning

confidence: 99%

Uptake and Reduction of Hexavalent Chromium by Aspergillus Niger and Aspergillus Parasiticus

Shugaba¹,

Buba²,

Bg³

et al. 2012

J Pet Environ Biotechnol

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The uptake and reduction of Cr(VI) by Aspergillus niger and A. parasiticus was studied in this journal. After 96 hours of growth, the culture solutions spiked with an initial dichromate concentration of 20 mg/l, were completely decolorized and had residual Cr(VI) concentrations of only 0.74 ± 0.55 and 1.69 ± 0.29 mg/l in A. niger and A. parasiticus cultures representing Cr(VI) removal of 96.3% and 91.6%, respectively. In the A. niger culture, significantly (P < 0.01) lower Cr(VI) concentrations were observed within 72 hours of growth compared to those of A. parasiticus, but in both cultures complete removal was almost achieved by 144 hours of growth. The rate of Cr(VI) removal was 0.21 ± 0.09 mgl -1 hr -1 and 0.20 ± 0.07 mgl -1 hr -1 for A. niger and A. parasiticus, respectively. Cellular concentrations of Cr(VI) in the two fungi increased significantly (P < 0.05 -0.001) with increasing concentrations of the dichromate treatments. Although tannic acid as sole source of carbon and energy gave significantly lower Cr(VI) removal than glucose (P < 0.001) and acetate (P < 0.01), it supported the removal of about 85.0% and 68.8% of the metal ion by A. niger and A. parasiticus, respectively. The active mycelia of both fungi showed significantly (P < 0.001) higher Cr(VI) removal than inactivated mycelia after incubation at 30°C for 72 hours. Incubation of cell -free extracts of both fungi with NADH at 30°C for 2 hours showed Cr(VI) reduction of 68.0% and 55.5% for A. niger and A. parasiticus, respectively. These findings suggest that uptake and metabolic reduction may be the process by which the two fungi are able to tolerate the toxic effects of hexavalent chromium. However, Cr removal via uptake by the two fungal biomass was observed to be in the range of 0.5 -1.78% only, for all the concentrations applied, which is insignificant when compared with the initial Cr concentration in the culture medium. The results obtained through this investigation indicate the possibility of treating waste effluents containing hexavalent chromium using Aspergillus niger and A. parasiticus.

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“…However, a hyper-resistant Bacillus sp. ES29 has been reported who is resistant to very high level of Cr (VI) at > 9.6 mM (Camargo et al, 2003b). In our experiments, higher Cr (VI) concentration (3.4 mM) caused decrease in growth rate when compared to growth at lower concentrations; this was ascribed to the toxic effect of Cr (VI).…”

Section: Discussionmentioning

confidence: 46%

Treatment of Chromium Pollution by the Reductase Enzyme Generated by a Chromium-Resistant Bacterium Isolated in Dewatering Sludge

Nguema

Luo²,

Mounir³

et al. 2017

IJB

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An efficient Cr (VI)-resistant and reducing bacterial strain was successfully isolated in dewatering sludge collected from a sewage treatment plant, and characterized in vitro Cr (VI) reduction through a reductase enzyme. Phylogenetic analysis using 16S rDNA gene sequencing revealed that the newly isolated strain namely Pf-1 was closely related to Bacillus cereus. The strain almost reduced 0.17 mM Cr (VI) within 24h incubation and the presence of different substrates such as glucose, sucrose, or acetate significantly enhanced the reduction rate of Cr (VI) to Cr (III). However, addition of the same substrate at the stationary phase of the microbial growth increased the reduction rate as well as bacterial growth. Additionally, raising the concentration of thiosulfate in the medium doubled the reduction rate under similar conditions. Assay with different fractions of the cells demonstrated that the reductase enzyme activity was mainly associated with the cytoplasmic fraction. The maximum activity was 23.3 µM h -1 mg -1 protein and was obtained at the Cr (VI) concentration of 2 mM. The promising strain can be efficiently employed for bioremediation of Cr (VI) polluted sites.

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In vitro reduction of hexavalent chromium by a cell-free extract of Bacillus sp. ES 29 stimulated by Cu 2+

Cited by 148 publications

References 17 publications

Isolation and Characterization of Chromium(VI)-Reducing Bacteria from Tannery Effluents

Isolation and Characterization of Chromium(VI)-Reducing Bacteria from Tannery Effluents

Uptake and Reduction of Hexavalent Chromium by Aspergillus Niger and Aspergillus Parasiticus

Treatment of Chromium Pollution by the Reductase Enzyme Generated by a Chromium-Resistant Bacterium Isolated in Dewatering Sludge

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