Characterization of the biochemical-pathway of uranium (VI) reduction in facultative anaerobic bacteria

Mtimunye, Phalazane Johanna; Chirwa, Evans M.N.

doi:10.1016/j.chemosphere.2014.03.105

Cited by 21 publications

(4 citation statements)

References 26 publications

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“…A strain with an interruption of the putative regulator of this operon did not show uranium reduction ability. In the wild-type strain, cadmium, a traditional thioredoxin inhibitor [111], also shut down uranium reduction [110]. These results stimulated the interpretation that it was the thioredoxin in conjunction with a putative oxidoreductase, both encoded in the operon, that were responsible for the reduction [112].…”

Section: Theory Calculations Have Also Indicated a U(v) Intermediate supporting

confidence: 49%

“…Further evidence for the importance of hydrogenases comes from South Africa. The ability of a microbial community to reduce uranium was inhibited by rotenone, a NADH-dependent hydrogenase inhibitor, suggesting that electrons going to uranium were coming through hydrogenase [111]. Hydrogenases were also found to be part of the uranium reduction pathway from Desulfovibrio species going through the periplasmic cytochrome c 3 [47].…”

Section: Factors Influencing Reduction Reaction Rates and Electron Flowmentioning

confidence: 90%

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Uranium Bio-Transformations: Chemical or Biological Processes?

Majumder¹,

Wall²

2017

OJIC

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Uranium bio-transformations are the many and varying types of interactions that microbes can have with uranium encountered in their environment. In this review, bio-transformations, including reduction, oxidation, respiration, sorption, mineralization, accumulation, precipitation, biomarkers, and sensors are defined and discussed. Consensus and divergences are noted in bioavailability, mechanism of uranium reduction, environment, metabolism and the type of organism. The breadth of organisms with characterized bio-trans formations is also cataloged and discussed. We further debate if uranium biotransformations provide bio-protection or bio-benefit to the microbe and highlight the need for more work in the field to understand if microbes use uranium reduction for energy gain and growth, as having the ability is separate from exercising it. The presentation centers on the fundamental drivers for these processes with an additional exposition of the essential contribution of inorganic chemistry techniques to the molecular characterization of these biological processes.

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Section: Theory Calculations Have Also Indicated a U(v) Intermediate supporting

confidence: 49%

Section: Factors Influencing Reduction Reaction Rates and Electron Flowmentioning

confidence: 90%

Uranium Bio-Transformations: Chemical or Biological Processes?

Majumder¹,

Wall²

2017

OJIC

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“…DNP dissipates the proton motive force associated with cellular electron transfer processes, and decreases hydrogen production by inhibiting the ATP synthesis by photophosphorylation, in the absence of a circuital current [28]. In contrast, rotenone inhibits the activity of NADH-dehydrogenase and blocks the reduction of U(VI) by facultative anaerobic bacteria in the absence of a circuital current [29]. The utilization of rotenone and DNP, in the presence and absence of a circuital current passing through the EAB cathodes of MFCs is thus expected to establish whether the circuital current and Cu(II) reduction are associated with cellular electron transfer processes in the EAB species.…”

Section: Introductionmentioning

confidence: 99%

Correlation between circuital current, Cu(II) reduction and cellular electron transfer in EAB isolated from Cu(II)-reduced biocathodes of microbial fuel cells

Shen

Huang

Zhou

et al. 2017

Bioelectrochemistry

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The performance of four indigenous electrochemically active bacteria (EAB) (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) was evaluated for Cu(II) reduction on the cathodes of microbial fuel cells (MFCs). These EAB were isolated from well adapted mixed cultures on the MFC cathodes operated for Cu(II) reduction. The relationship between circuital current, Cu(II) reduction rate, and cellular electron transfer processes was investigated from a mechanistic point of view using X-ray photoelectron spectroscopy, scanning electronic microscopy coupled with energy dispersive X-ray spectrometry, linear sweep voltammetry and cyclic voltammetry. JY1 and JY5 exhibited a weak correlation between circuital current and Cu(II) reduction. A much stronger correlation was observed for JY3 followed by JY6, demonstrating the relationship between circuital current and Cu(II) reduction for these species. In the presence of electron transfer inhibitors (2,4-dinitrophenol or rotenone), significant inhibition on JY6 activity and a weak effect on JY1, JY3 and JY5 was observed, confirming a strong correlation between cellular electron transfer processes and either Cu(II) reduction or circuital current. This study provides evidence of the diverse functions played by these EAB, and adds to a deeper understanding of the capabilities exerted by diverse EAB associated with Cu(II) reduction.

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“…This suggests an external precipitation mechanism as opposed to an internal mechanism coupled with an excretion mechanism. Potentially, a surface electron transfer mechanism could be active for direct Pb(II) reduction similar to that proposed by Mtimunye and Chirwa (2014) for the microbial reduction in U(VI) to U(IV). Alternatively, or additionally, sulphur-containing amino -acids could be metabolised intracellularly, coupled with the excretion of sulphide to the medium which would then precipitate PbS on contact with dissolved Pb(II) in the medium.…”

Section: Sem-edx and Xpsmentioning

confidence: 69%

Microbial Pb(II)-precipitation: the influence of oxygen on Pb(II)-removal from aqueous environment and the resulting precipitate identity

Brink

Horstmann

Peens

2019

Int. J. Environ. Sci. Technol.

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The study aimed to quantify the lead(II) bio-precipitation effectiveness, and the produced precipitate identities, of industrial consortia under aerobic and anaerobic batch conditions. The consortia were obtained from an automotive battery recycling plant and an operational lead mine in South Africa. The experiments were performed in the complex growth medium Luria-Bertani broth containing 80 ppm lead(II). The precipitation and corresponding removal of lead(II) were successfully achieved for both aerobic (yellow/brown precipitate) and anaerobic (dark grey/black precipitate) conditions. The removal of lead(II) followed similar trends for both aeration conditions, with the majority of lead(II) removed within the initial 48 h, followed by a marked decline in removal rate for the remainder of the experiments. The final lead(II) removal ranged between 78.11 ± 4.02% and 88.76 ± 3.98% recorded after 144 h. The precipitates were analysed using XPS which indicated the presence of exclusively PbO and elemental lead in the aerobic precipitates, while PbO, PbS, and elemental lead were present in the anaerobic precipitates. The results indicated an oxidationreduction mechanism with lead(II) as an electron acceptor in both aerobic and anaerobic conditions, while a sulphide-liberation catabolism of sulphur-containing amino acids was evident exclusively in the anaerobic runs. This study provides the first report of bacterial bio-reduction in aqueous lead(II) to elemental lead through a dissimilatory lead reduction mechanism. It further provides support for the application of bioremediation for the removal and recovery of lead from industrial waste streams through the application of bacterial biocatalysts for direct elemental lead recovery.

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Characterization of the biochemical-pathway of uranium (VI) reduction in facultative anaerobic bacteria

Cited by 21 publications

References 26 publications

Uranium Bio-Transformations: Chemical or Biological Processes?

Uranium Bio-Transformations: Chemical or Biological Processes?

Correlation between circuital current, Cu(II) reduction and cellular electron transfer in EAB isolated from Cu(II)-reduced biocathodes of microbial fuel cells

Microbial Pb(II)-precipitation: the influence of oxygen on Pb(II)-removal from aqueous environment and the resulting precipitate identity

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