Reduction of Cr(VI) by Escherichia coli BL21 in the presence of redox mediators

Guo, Jianbo; Lian, Jing; Xu, Zhifang; Xi, Zairong; Yang, Jingliang; Jefferson, William A.; Chun, Liu; Li, Zaixing; Yue, Lin

doi:10.1016/j.biortech.2012.07.090

Cited by 33 publications

(23 citation statements)

References 11 publications

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“…These have been used in UASB reactors and in activated carbon packed USPBR reactors for the removal of azo dyes [15,34]. Although previous study have indicated a possible protonation of quinone to form phenolic groups at pHs lower than 6.5, and this in turn would hamper the electron shuttling effect of lawsone [35], Guo et al yet found an optimum pH 6.0 for quinone groups functioned as active RMs during the enhanced anaerobic reduction of oxidized pollutants [36]. Thus, the nealy neutral and very weak acid pHs in this study (Fig.…”

Section: Redox Mediator For Ao7 Reductionmentioning

confidence: 97%

Enhanced azo dye removal in a continuously operated up-flow anaerobic filter packed with henna plant biomass

Huang

Chen

et al. 2015

Journal of Hazardous Materials

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Section: Redox Mediator For Ao7 Reductionmentioning

confidence: 97%

Enhanced azo dye removal in a continuously operated up-flow anaerobic filter packed with henna plant biomass

Huang

Chen

et al. 2015

Journal of Hazardous Materials

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“…To confirm that the large current reduction was not attributable to slower reactions upstream of OM Cyt c due to the presence of deuterium ions,weexamined the effect of D 2 OonI c in the presence of anthraquinone-1-sulfonate (a-AQS), which functions as as huttling mediator for the transport of both electrons and protons that are in the electron-transport chain and are located in the inner membrane or periplasm. [10] In the presence of 100 mm a-AQS,t he I c was limited by diffusion ( Figure S1 in the Supporting Information) and the addition of D 2 Ohad minimal impact on the I c (Figure 2b and d), thus indicating that the potential delay of upstream reactions by deuterium ions did not cause the large KIE. Based on these results,t he large KIE could be attributed to the EET process by OM Cyts c.…”

mentioning

confidence: 91%

Proton Transport in the Outer‐Membrane Flavocytochrome Complex Limits the Rate of Extracellular Electron Transport

et al. 2017

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The microbial transfer of electrons to extracellularly located solid compounds,t ermed extracellular electron transport (EET), is critical for microbial electrode catalysis. Although the components of the EET pathway in the outer membrane (OM) have been identified, the role of electron/ cation coupling in EET kinetics is poorly understood. We studied the dynamics of proton transport associated with EET in an OM flavocytochrome complex in Shewanella oneidensis MR-1. Using aw hole-cell electrochemical assay,as ignificant kinetic isotope effect (KIE) was observed following the addition of deuterated water (D 2 O). The removal of af lavin cofactor or key components of the OM flavocytochrome complex significantly increased the KIE in the presence of D 2 O to values that were significantly larger than those reported for proton channels and ATPsynthase,thus indicating that proton transport by OM flavocytochrome complexes limits the rate of EET.

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“…Humic substances and quinone analogues can shuttle electrons from bacterial cells to electrophilic pollutants and facilitate their biotransformation (Van der Zee and Cervantes 2009). The addition of redox mediator anthraquinone-2-sulfonate (AQS) has been shown to enhance Cr(VI) reduction by resting cells under anaerobic culture (Guo et al 2012;Liu et al 2010). However, the study on AQS-promoted aerobic Cr(VI) reduction is limited.…”

Section: Introductionmentioning

confidence: 99%

Chromate Interaction with the Chromate Reducing ActinobacteriumIntrasporangium chromatireducensQ5-1

Liu

Huang

Zhang

et al. 2015

Geomicrobiology Journal

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This study was conducted to determine the microbe-chromate [Cr(VI)] interaction and the effect of quinoid analogue anthraquinone-2-sulfonate (AQS) on aerobic Cr(VI) reduction by Intrasporangium chromatireducens Q5-1. The addition of redox mediator AQS, which might expedite the electron transfer, promoted Cr(VI) bioreduction. Addition of carbon sources, such as maltose, acetate, sucrose and lactose stimulated the AQS-promoted Cr(VI) reduction of strain Q5-1. Induction experiment clarified that the enzyme involves in the Cr(VI) reduction is constitutive. Energy-dispersive spectroscopy (EDS) spectra showed the existence of trace Cr distributed on the cell surface. X-ray photoelectron spectroscopy (XPS) analysis revealed that the Cr(III) complex was bound to the cell surface (0.87%, atomic percent). The spectra shifts detected by Fourier transform infrared (FTIR) spectroscopy indicated that Cr(III) was bound to the carbonyl and amide groups. In addition, Cr(VI) reduction by different cell fractions showed that Cr(VI) reduction was occurred extracellularly rather than intracellularly. The results disclosed that Cr(VI) detoxification of strain Q5-1 was mainly associated with extracellular Cr(VI) reduction process in combination with trace Cr(III) adsorption on the cell surface. A schematic figure depicting the interactions between strain Q5-1 and Cr(VI) was presented. This study enhanced the understanding of the microbe-Cr(VI) interaction mechanism and revealed the AQS-promoted aerobic Cr(VI) reduction of strain Q5-1. Such strain and quinoid analogue-mediated bacterial Cr(VI) reduction may facilitate the bioremediation for Cr(VI)-polluted environment.

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Reduction of Cr(VI) by Escherichia coli BL21 in the presence of redox mediators

Cited by 33 publications

References 11 publications

Enhanced azo dye removal in a continuously operated up-flow anaerobic filter packed with henna plant biomass

Enhanced azo dye removal in a continuously operated up-flow anaerobic filter packed with henna plant biomass

Proton Transport in the Outer‐Membrane Flavocytochrome Complex Limits the Rate of Extracellular Electron Transport

Chromate Interaction with the Chromate Reducing ActinobacteriumIntrasporangium chromatireducensQ5-1

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