Ex situ bioremediation of Cr(VI) contaminated soil by Bacillus sp.: Batch and continuous studies

Kathiravan, Mathur Nadarajan; Karthick, R.; Muthukumar, Karuppan

doi:10.1016/j.cej.2011.02.060

Cited by 109 publications

(31 citation statements)

References 29 publications

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“…(Kathiravan et al 2011). However, higher inoculation volumes (over 30 %) failed to elicit further increases in Cr(VI) reduction, suggesting either that bacterial concentration is rapidly saturated at 20 % of inoculum or that competition for limited nutritional resources restricts the bacterial metabolic activity in Cr(VI) reduction.…”

Section: Discussionmentioning

confidence: 93%

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation

Zhou

Dong

et al. 2012

Appl Microbiol Biotechnol

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A bacterial isolate (G161) with high Cr(VI)-reducing capacity was isolated from Cr(VI)-contaminated soil and identified as Leucobacter sp. on the basis of 16S rRNA gene sequence analysis. The isolate was a Gram-positive, aerobic rod. The hexavalent chromate-reducing capability of the isolate was investigated under three conditions of oxygen stress. The isolate was found to reduce Cr(VI) under all conditions but performed most effectively during aerobic growth followed by facultative anaerobic incubation. Under these conditions, the isolate tolerated K(2)Cr(2)O(7) concentrations up to 1,000 mg/l and completely reduced 400 mg/l K(2)Cr(2)O(7) within 96 h. The strain reduced Cr(VI) over a wide range of pH (6.0-11.0) and temperatures (15-45 °C) with optimum performance at pH 8.0 and 35 °C. The presence of other metals, such as Ca(2+), Co(2+), Cu(2+), Mn(2+), Ni(2+), and Zn(2+), induced no effect or else played a stimulatory role on Cr(VI)-reduction activity of the strain. The strain was tested for Cr(VI) removal in wastewaters and proved capable of completely reducing the contained Cr(VI). This is the novel report of a bacterial growth and Cr(VI)-reduction process under sequential aerobic growth and facultative anaerobic conditions. The study suggested that the isolate possesses a distinct capability for Cr(VI) reduction which could be harnessed for the detoxification of chromate-contaminated wastewaters.

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Section: Discussionmentioning

confidence: 93%

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation

Zhou

Dong

et al. 2012

Appl Microbiol Biotechnol

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“…We have previously determined the minimum inhibitory concentration (MIC) of Cr(VI) of Bacillus sp. to be 600 mg/L [28]. This isolate was used for calcium alginate immobilization and other mass transfer studies.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of steady state and unsteady state mass transfer rate of Cr(VI) in immobilized Bacillus sp.

Kathiravan

Gim

Ryu

et al. 2015

Biotechnol Bioproc E

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A novel hexavalent chromium (CrVI)-removing Bacillus sp. was isolated from leather industry wastewatercontaminated soil. This potential isolate was subjected to Cr(VI) removal under free and immobilized states in a stirred batch reactor (SBR). Two biokinetic parameters, V max and K m , and the effective diffusivity (D e ) for various bead sizes were calculated from Lineweaver-Burk and Eadie-Hoftsee plots, respectively. With respect to bead size, D e decreased significantly from a maximum of 3.024 × 10 −6 cm 2 /sec in the 0.20 cm bead to 2.948 × 10 −6 , 1.775 × 10 −7 , and 1.144 × 10 −7 cm 2 /sec in the 0.40-, 0.60-and 0.80 cm beads, respectively. Additionally, steady and unsteady state modeling of diffusional mass transfer into the immobilized beads was conducted to determine the mass transfer rate as a function of time and the beads' radial profile. Furthermore, the space-time yield (STY) was modeled according to the residence time of the reactor. The reactor's STY was reasonable and could be further boosted by increasing the fractional biocatalyst.

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“…These groups serve as the electron donor group in the water extract of biomaterials [31][32][33][34]. Among the sugars present in the cell wall of biomaterials, glucose has the highest electron-donating efficiency [35]. Presence of reducing sugar in the water extract of Sajina flower is confirmed by the positive response in the Molish test.…”

Section: Introductionmentioning

confidence: 90%

Surfactant-assisted enhancement of bioremediation rate for hexavalent chromium by water extract of Sajina (Moringa oleifera) flower

Mukherjee

Nandi

Saha

et al. 2015

Desalination and Water Treatment

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A B S T R A C TThe presence of hexavalent chromium in waste water is a serious environmental problem due to its toxicity and carcinogenicity. Bioremediation is an efficient alternative to the conventional chemical methods of treatment. Bioremediation of toxic hexavalent chromium is done by the reduction of hexavalent chromium to relatively less toxic trivalent chromium. In this study, water extract of Sajina flower, which contains different types of reducing components such as sugar, amino acid, is used as reductant and the rate of bioremediation is increased by treatment with anionic and neutral surfactants. Here surfactants are used as catalyst in the bioremediation process. Sodiumdodecyl sulfate (SDS) is found to be the best catalyst. In the absence of surfactants, 60.37% of the total chromium(VI) is reduced within 285 h, whereas the removal percentage increases up to 96.25 and 99.37% in the presence of TX-100 and SDS, respectively, in minimum time.

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Ex situ bioremediation of Cr(VI) contaminated soil by Bacillus sp.: Batch and continuous studies

Cited by 109 publications

References 29 publications

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation

Evaluation of steady state and unsteady state mass transfer rate of Cr(VI) in immobilized Bacillus sp.

Surfactant-assisted enhancement of bioremediation rate for hexavalent chromium by water extract of Sajina (Moringa oleifera) flower

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