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Journal ArticleDOI

Biosensing and bioremediation of Cr(VI) by cell free extract of Enterobacter aerogenes T2.

10 Jan 2014-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering (J Environ Sci Health A Tox Hazard Subst Environ Eng)-Vol. 49, Iss: 5, pp 600-608
TL;DR: Calcium alginate beads, modified with CFE of E. aerogenes, could be used in bioremediation of Cr(VI) since it could work in real conditions with extraordinarily high capacity and could be a viable alternative to costly measurement procedures.
Abstract: Hexavalent chromium or Cr(VI) enters the environment through several anthropogenic activities and it is highly toxic and carcinogenic. Hence it is required to be detected and remediated from the environment. In this study, low-cost and environment-friendly methods of biosensing and bioremediation of Cr(VI) have been proposed. Crude cell free extract (CFE) of previously isolated Enterobacter aerogenes T2 (GU265554; NII 1111) was prepared and exploited to develop a stable biosensor for direct estimation of Cr(VI) in waste water, by using three electrodes via cyclic voltammetry. For bioremediation studies, a homogeneous solution of commercially available sodium alginate and CFE was added dropwise in a continuously stirred calcium chloride solution. Biologically modified calcium alginate beads were produced and these were further utilized for bioremediation studies. The proposed sensor showed linear response in the range of 10-40 μg L(-1) Cr(VI) and the limit of detection was found to be 6.6 μg L(-1) Cr(VI). No interference was observed in presence of metal ions, e.g., lead, cadmium, arsenic, tin etc., except for insignificant interference with molybdenum and manganese. In bioremediation studies, modified calcium alginate beads showed encouraging removal rate 900 mg Cr(VI)/m(3) water per day with a removal efficiency of 90%, much above than reported in literature. The proposed sensing system could be a viable alternative to costly measurement procedures. Calcium alginate beads, modified with CFE of E. aerogenes, could be used in bioremediation of Cr(VI) since it could work in real conditions with extraordinarily high capacity.
Citations
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Journal ArticleDOI
16 Aug 2016-Sensors
TL;DR: The developed MFC biosensor has potential as an early warning detection device for Cr(VI) determination even if O. anthropi YC152 is a possible opportunistic pathogen.
Abstract: Fast hexavalent chromium (Cr(VI)) determination is important for environmental risk and health-related considerations. We used a microbial fuel cell-based biosensor inoculated with a facultatively anaerobic, Cr(VI)-reducing, and exoelectrogenic Ochrobactrum anthropi YC152 to determine the Cr(VI) concentration in water. The results indicated that O. anthropi YC152 exhibited high adaptability to pH, temperature, salinity, and water quality under anaerobic conditions. The stable performance of the microbial fuel cell (MFC)-based biosensor indicated its potential as a reliable biosensor system. The MFC voltage decreased as the Cr(VI) concentration in the MFC increased. Two satisfactory linear relationships were observed between the Cr(VI) concentration and voltage output for various Cr(VI) concentration ranges (0.0125–0.3 mg/L and 0.3–5 mg/L). The MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in drinking water, groundwater, and electroplating wastewater in 45 min with low deviations (<10%). The use of the biosensor can help in preventing the violation of effluent regulations and the maximum allowable concentration of Cr(VI) in water. Thus, the developed MFC biosensor has potential as an early warning detection device for Cr(VI) determination even if O. anthropi YC152 is a possible opportunistic pathogen.

33 citations


Cites background or result from "Biosensing and bioremediation of Cr..."

  • ...Compared with previous studies [9,13,15,17], our results demonstrate that the developed Cr(VI) biosensor has an appropriate detection limit range for Cr(VI) (0....

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  • ...Panda and Sarkar (2014) developed a stable biosensor by using crude cell-free extracts of Enterobacter aerogenes immobilized with calcium alginate beads for the direct estimation of Cr(VI) in wastewater [17]....

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Journal ArticleDOI
01 Dec 2018
TL;DR: In this article, a new Ag6S6 cluster-based coordination compound formulated as Ag6(dmpymt)6 (1) (HdMPymt = 4,6-dimethylpyrimidine-2-thione) was synthesized under solvothermal condition and displayed apparently green luminescence emission and good stabilities in water and some organic solvents.
Abstract: With the increasing need of detecting chemical pollutants, modern analytical instruments show many advantages but also have some common drawbacks such as high operational cost and tedious pretreatment procedures. Thus, developing a fast, simple, and convenient colorimetric sensing system is a challenge. Here, a new Ag6S6 cluster-based coordination compound formulated as Ag6(dmpymt)6 (1) (Hdmpymt = 4,6-dimethylpyrimidine-2-thione) was synthesized under solvothermal condition and displayed apparently green luminescence emission and good stabilities in water and some organic solvents. Fluorescence experiments illustrated that 1 displayed efficiently naked eye colorimetric sensing for nitrobenzene (NB), Cr(VI), and Fe(III) ions by fluorescence quenching in the emulsions. The possible sensing mechanisms are attributed to the competitive absorption of excitation wavelength energy between the analytes and the compound 1. Furthermore, the fluorescent test papers of 1 were prepared as well and showed efficient, convenient, and easily recycled characteristics, presenting a potential sensing application for the environmental concerns.

20 citations

Journal ArticleDOI
TL;DR: A plausible mechanism of biodegradation of Carbendazim has been proposed here, as the isolate's growth curve and the rate kinetics mathematically fitted well with Gompertz model and second order reaction, respectively.

18 citations

Journal ArticleDOI
TL;DR: In this paper, a new tripodal chemosensor named PoPAP for colorimetric-enhancing detection of four metal ions from first-row transition series by combining pyridyl and phenolic binding sites with a highly conjugated pyrin-1,3,4-oxadiazolyl-phenyl moiety was designed, synthetized, and structurally analyzed.

13 citations

Journal ArticleDOI
TL;DR: In this article, a biosorption-based remediation strategy is proposed for the remediation of carcinogenic heavy metal chromium from contaminated samples, where the cell-free extract (CFE) was prepared and encapsulated in spherical calcium alginate biopolymeric beads.
Abstract: Carcinogenic heavy metal chromium, in its hexavalent form Cr(VI) is spuriously used in various industrial operations because of its hardness and stability. Due to lack of proper remediation processes, effluents contain Cr(VI) in large excess of WHO’s statutory limit of 50 μg l−1. In this study, a biosorption-based remediation strategy is proposed for the remediation of Cr(VI) from contaminated samples. The novel bacterial strain Enterobacter aerogenes T2 (GU265554, NII 1111) was isolated from Cr(VI)-contaminated tannery effluent and used for bioremediation studies. The cell-free extract (CFE) was prepared and encapsulated in spherical calcium alginate biopolymeric beads. A semi-batch plug-flow-packed bed made of these beads was used for biosorption of Cr(VI). A remediation rate of 932 mg Cr(VI) m−3 water per day with a sorption efficiency of 93.2 % was achieved. The method exhibited the best results when compared to those reported in the literature. Various isotherm models of adsorption such as Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) were studied. The results predicted adsorption in a multi-layered fashion via physisorption. The developed technology could be considered as green since no synthetic chemical was used for sorption of Cr(VI).

11 citations


Cites background or methods from "Biosensing and bioremediation of Cr..."

  • ...Cr(VI)-contaminated real environmental samples in batch operation (Panda and Sarkar 2014)....

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  • ...The optimized dosage of beads was used to observe bioremediation of various concentrations of Cr(VI) (10, 20, 30, 40, 50, 60 mg l) in M2 media, at environmental conditions (room temperature of 37 °C and physiological pH of 7), till Cr(VI) was completely transformed (Panda and Sarkar 2014)....

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  • ...The whole cells of the said strain could remediate Cr(VI) from spiked tap water as well as Cr(VI)-contaminated real environmental samples in batch operation (Panda and Sarkar 2014)....

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  • ...The optimized dosage of beads was used to observe bioremediation of various concentrations of Cr(VI) (10, 20, 30, 40, 50, 60 mg l−1) in M2 media, at environmental conditions (room temperature of 37 °C and physiological pH of 7), till Cr(VI) was completely transformed (Panda and Sarkar 2014)....

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References
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01 Aug 2008
TL;DR: The Limit of Blank, Limit of Detection, and Limit of Quantitation are terms used to describe the smallest concentration of a measurand that can be reliably measured by an analytical procedure.
Abstract: * Limit of Blank (LoB), Limit of Detection (LoD), and Limit of Quantitation (LoQ) are terms used to describe the smallest concentration of a measurand that can be reliably measured by an analytical procedure. * LoB is the highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested. LoB = mean(blank) + 1.645(SD(blank)). * LoD is the lowest analyte concentration likely to be reliably distinguished from the LoB and at which detection is feasible. LoD is determined by utilising both the measured LoB and test replicates of a sample known to contain a low concentration of analyte. * LoD = LoB + 1.645(SD (low concentration sample)). * LoQ is the lowest concentration at which the analyte can not only be reliably detected but at which some predefined goals for bias and imprecision are met. The LoQ may be equivalent to the LoD or it could be at a much higher concentration.

1,656 citations


"Biosensing and bioremediation of Cr..." refers background in this paper

  • ...4), the Limit of quantification, or LoQ (a value in the form of smallest concentration of a measure that can be reliably measured by an analytical procedure), was found to be 20 μg L−1 Cr(VI)[20][10(SD/S) = 10 × 1....

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Journal ArticleDOI
TL;DR: In this study, strains that are capable of bioaccumulating Cr(VI) were isolated from treated tannery effluent of a common effluent treatment plant and biosorption capabilities of living and dead cells were analysed.

501 citations


"Biosensing and bioremediation of Cr..." refers background in this paper

  • ...Furthermore, Cr(VI) can accumulate in placenta, impairing foetal development in mammals.[4] Hence, detection or sensing along with quantification and subsequent remediation of Cr(VI) from industrial effluent, drinking water is necessary....

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Journal ArticleDOI
TL;DR: It is demonstrated that Cr(III) within ultramafic- and serpentinite-derived soils/sediments can be oxidized and dissolved through natural processes, leading to hazardous levels of aqueous Cr(VI) in surface and groundwater.
Abstract: Naturally occurring Cr(VI) has recently been reported in ground and surface waters. Rock strata rich in Cr(III)-bearing minerals, in particular chromite, are universally found in these areas that occur near convergent plate margins. Here we report experiments demonstrating accelerated dissolution of chromite and subsequent oxidation of Cr(III) to aqueous Cr(VI) in the presence of birnessite, a common manganese mineral, explaining the generation of Cr(VI) by a Cr(III)-bearing mineral considered geochemically inert. Our results demonstrate that Cr(III) within ultramafic- and serpentinite-derived soils/sediments can be oxidized and dissolved through natural processes, leading to hazardous levels of aqueous Cr(VI) in surface and groundwater.

445 citations


"Biosensing and bioremediation of Cr..." refers background in this paper

  • ...In the Earth’s crust, chromium is concentrated (> 200 mg Kg−1 or mg L−1) in ultramafic rocks and serpentinities of ophiolite complexes that constitute ∼1% of the terrestrial landscape, primarily within populated areas of Circum-Pacific and Mediterranean region.[1] Chromium (a heavy metal belonging to group VIB in the periodic table, having atomic number 24) in its hexavalent form is widely used in industrial operations (leather tanning, electroplating, paints/pigment production, steel manufacture, etc....

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Journal ArticleDOI
TL;DR: The chromate-reducing ability of Pseudomonas aeruginosa A2Chr was compared in batch culture, with cells entrapped in a dialysis sac, and with cells immobilized in an agarose-alginate film in conjunction with a rotating biological contactor to achieve maximum Cr(VI) reduction.
Abstract: The chromate-reducing ability of Pseudomonas aeruginosa A2Chr was compared in batch culture, with cells entrapped in a dialysis sac, and with cells immobilized in an agarose-alginate film in conjunction with a rotating biological contactor. In all three systems, the maximum Cr(VI) reduction occurred at 10 mg Cr(VI)/l. Whereas at 50 mg Cr(VI)/l concentration, only 16% of the total Cr(VI) was reduced, five spikings with 10 mg chromate/l at 2-h intervals led to 96% reduction of the total input of 50 mg Cr(VI)/l. Thus maximum Cr(VI) reduction was achieved by avoiding Cr(VI) toxicity to the cells by respiking with lower Cr(VI) concentrations. At 10 mg Cr(VI)/l, the pattern of chromate reduction in dialysis-entrapped cells was almost similar to that of batch culture and 86% of the bacterially reduced chromium was retained inside the dialysis sac. In electroplating effluent containing 100 mg Cr(VI)/l, however, the amount of Cr(VI) reduced by the cells immobilized in agarose-alginate biofilm was twice and thrice the amount reduced by batch culture and cells entrapped in a dialysis sac, respectively.

240 citations


"Biosensing and bioremediation of Cr..." refers background in this paper

  • ...Microbial uptake and reduction of toxic Cr(VI) has practical importance, because biological strategies provide green technology, which is also cost effective.[11] Adsorption is the most frequently applied technique due to its advantages such as variety of adsorbent materials and high efficiency at a relatively low cost....

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Journal ArticleDOI
TL;DR: The effects of some environmental factors such as pH, temperature, and time on Cr(VI) reduction and resistance are described and it is found that chromium-resistant bacteria can tolerate 2500 mg L(-1)Cr(VI), but most of the isolates tolerated and reduced Cr( VI) at concentrations lower than 1500 mg L (-1).
Abstract: Extensive use of hexavalent chromium [Cr(VI)] in various industrial applications has caused substantial environmental contamination. Chromium-resistant bacteria isolated from soils can be used to remove toxic Cr(VI) from contaminated environments. This study was conducted to isolate chromium-resistant bacteria from soils contaminated with dichromate and describes the effects of some environmental factors such as pH, temperature, and time on Cr(VI) reduction and resistance. We found that chromium-resistant bacteria can tolerate 2500 mg L(-1) Cr(VI), but most of the isolates tolerated and reduced Cr(VI) at concentrations lower than 1500 mg L(-1). Chromate reduction activity of whole cells was detected in five isolates. Most of these isolates belong to the genus Bacillus as identified by the 16S rRNA gene sequencing. Maximal Cr(VI) reduction was observed at the optimum pH (7.0-9.0) and temperature (30 degrees C) of growth. One bacterial isolate (Bacillus sp. ES 29) was able to aerobically reduce 90% of Cr(VI) in six hours. The Cr(VI) reduction activity of the whole cells of five isolates had a K(M) of 0.271 (2.61 mM) to 1.51 mg L(-1) (14.50 mM) and a V(max) of 88.4 (14.17 nmol min(-1)) to 489 mg L9-1) h(-1) (78.36 nmol min(-1)). Our consortia and monocultures of these isolates can be useful for Cr(VI) detoxification at low and high concentrations in Cr(VI)-contaminated environments and under a wide range of environmental conditions.

235 citations


"Biosensing and bioremediation of Cr..." refers methods in this paper

  • ...There exist a number of conventional methods for removing toxic chromium ion such as chemical reduction followed by precipitation, ion-exchange and adsorption on activated coal, alum, kaolinite and ash.[10] However, the costs of the required equipment and the operational costs are prohibitively high for large-scale treatment....

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