Ligand mediated reduction of c-type cytochromes by Fe(II): Kinetic and mechanistic insights

Wang, Ying; Yuan, Xiuliang; Li, Xiaomin; Li, Fangbai; Liu, Tongxu

doi:10.1016/j.chemgeo.2019.03.006

Cited by 13 publications

(9 citation statements)

References 53 publications

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“…The kinetics of reduction of EOCs (MW > 3000) or flavins were separately examined by cells (OD 600 = 0.2) with OM-bound c -Cyts (bound-Cyts) and lactate (30 mM). Fully reduced EOCs (MW > 3000) or flavins and solutions of Cr(VI) were immediately loaded into separate syringes of an Applied Photosystems (Leatherhead, United Kingdom) SX20 stopped-flow apparatus and mixed rapidly under control of the software. Results of a control experiment without added Cr(VI) as an electron acceptor showed that nearly identical kinetic curves and initial c -Cyt red concentrations were observed in 10 repeat cycles (Figure S3a), and less than 6.0% of the initial c -Cyt red was decreased after 20 min (Figure S3b); so, residual oxidation of c -Cyt red by oxygen intrusion was negligible.…”

Section: Methodsmentioning

confidence: 99%

Extracellular Electron Shuttling Mediated by Soluble c-Type Cytochromes Produced by Shewanella oneidensis MR-1

Liu¹,

Luo

Wu³

et al. 2020

Environ. Sci. Technol.

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How metal-reducing bacteria transfer electrons during dissimilatory energy generation under electron acceptor-limited conditions is poorly understood. Here, we incubated the iron and manganese-reducing bacterium Shewanella oneidensis MR-1 without electron acceptors. Removal of soluble extracellular organic compounds (EOCs) dramatically retarded transfer of electrons to an experimental electron acceptor, Cr(VI), by MR-1. However, the return of either high MW (>3000 Da) or low MW (<3000 Da) soluble EOCs produced by MR-1 to washed cells restored Cr(VI) reduction though Cr(VI) reduction was fastest when both size fractions were added together. Spectral and electrochemical characterization of EOCs indicated the presence of flavins and c-type cytochromes (c-Cyts). A model of the kinetics of individual elementary reactions between cells, flavins, released c-Cyts, and Cr(VI), including the direct reduction of flavins, released c-Cyts, and Cr(VI) by cells and the indirect reduction of Cr(VI) by reduced forms of flavins and released c-Cyts, was developed. Model results suggest that released c-Cyts could act as electron mediators to accelerate electron transfer from cells to Cr(VI), and the relative contribution of this pathway was higher than that mediated by flavins. Hence, extracellular c-Cyts produced by MR-1 likely play a role in extracellular electron transfer under electron acceptor-limited conditions. These findings provide new insights into extracellular electron shuttling and the metabolic strategy of metal-reducing bacteria under electron acceptor-limited conditions.

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Section: Methodsmentioning

confidence: 99%

Extracellular Electron Shuttling Mediated by Soluble c-Type Cytochromes Produced by Shewanella oneidensis MR-1

Liu¹,

Luo

Wu³

et al. 2020

Environ. Sci. Technol.

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“…More importantly, biofilm accumulation was remarkably responsible for the increased intensities of the CC and C–H peaks, which implied that the higher degree of graphitization of the GO sheet surface achieved via microbial modification was beneficial for the formation of rGO. ,, Using the results of the Raman, FTIR, and XPS analyses, it could be suggested that the modification of GO composites evolved toward the formation of rGO, and the characteristics of the GO composites eventually became similar to those of rGO. Because rGO contains redox active quinoid groups that are highly responsible for promoting Cr(VI) bioreduction, , the catalytic capacity of biofilms was also correspondingly increased. Thus, this could be another reason for explaining the increased Cr(VI) reduction governed by S. xiamenensis– GO/PVA biofilms.…”

Section: Resultsmentioning

confidence: 99%

“…39,48,49 Using the results of the Raman, FTIR, and XPS analyses, it could be suggested that the modification of GO composites evolved toward the formation of rGO, and the characteristics of the GO composites eventually became similar to those of rGO. Because rGO contains redox active quinoid groups that are highly responsible for promoting Cr(VI) bioreduction, 50,51 the catalytic capacity of biofilms was also correspondingly increased. Thus, this could be another reason for explaining the increased Cr(VI) reduction governed by S. xiamenensis−GO/PVA biofilms.…”

Section: Acs Sustainable Chemistry and Engineeringmentioning

confidence: 99%

Highly Efficient and RecyclableShewanella xiamenensis-Grafted Graphene Oxide/Poly(vinyl alcohol) Biofilm Catalysts for Increased Cr(VI) Reduction

Luo

Chen

et al. 2019

ACS Sustainable Chem. Eng.

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An integrated assembled recyclable catalytic material was fabricated by grafting Shewanella xiamenensis (S. xiamenensis) onto poly(vinyl alcohol)/graphene oxide films (denoted as S. xiamenensis–GO/PVA biofilms) with different GO-to-PVA mass ratios (i.e., 4:1, 2:1, 1:1, 1:2, and 1:4 in 10 mg of GO-PVA mixtures). During a 48 h test, the S. xiamenensis–GO/PVA biofilms demonstrated increased Cr(VI) removal efficiency of up to 100% for 50 mg/L Cr(VI). Moreover, the assembled films displayed desirable biocompatibility, satisfactory catalysis of Cr(VI) removal, and outstanding recyclability in reaction cycles (over 10 runs). The complete removal of Cr(VI) in the presence of S. xiamenensis–GO/PVA biofilms required approximately 9–24 h, compared with 48 h for the control group. In addition, the catalytic efficiency was gradually increased during recycling owing to the greater biomass accumulation on the films’ surface for each circular reaction. Moreover, GO was modified and evolved owing to the microbial activity of S. xiamenensis and eventually exhibited characteristics similar to those of reduced graphene oxide (rGO) (which could serve as an electron shuttle). The dual changes could synergistically facilitate the extracellular electron transfer governed by the direct contact mechanism as well as by the electron shuttle. Shewanella xiamenensis–GO/PVA biofilms outperformed conventional catalysis and could represent a promising technology for the remediation of Cr(VI)-polluted wastewater or soils.

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“…Furthermore, depending on the specific chelating agents the oxidation-reduction potentials and photon absorption capacities of the metal-ligand complexes can be shifted [41]. The apparent catalytic effects of Fe Ⅱ NTA and Fe Ⅲ NTA redox have been explored for enhancing photo-Fenton oxidation [39], persulfate activation [42], cytochrome c reduction [43] and electro-Fenton reactions [44]. Moreover, the 2 nd -order rate constant of Fe Ⅱ NTA with •OH at circumneutral pH (5.0×10 9 M -1 •s -1 , pH=6.2) [45] is higher than Fe 2+ + •OH (3.5×10 8 M -1 •s -1 , pH=4.5-6.2) [20] and NTA + •OH (5.5×10 8 M -1 •s -1 , pH=6.0) [46], therefore Fe Ⅱ NTA may have a higher efficiency in preventing the geminate recombination of eaqwith •OH.…”

Section: Introductionmentioning

confidence: 99%

UV/FeⅡNTA as a novel photoreductive system for the degradation of perfluorooctane sulfonate (PFOS) via a photoinduced intramolecular electron transfer mechanism

Sun

Zhang

JinChi

et al. 2022

Chemical Engineering Journal

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Ligand mediated reduction of c-type cytochromes by Fe(II): Kinetic and mechanistic insights

Cited by 13 publications

References 53 publications

Extracellular Electron Shuttling Mediated by Soluble c-Type Cytochromes Produced by Shewanella oneidensis MR-1

Extracellular Electron Shuttling Mediated by Soluble c-Type Cytochromes Produced by Shewanella oneidensis MR-1

Highly Efficient and RecyclableShewanella xiamenensis-Grafted Graphene Oxide/Poly(vinyl alcohol) Biofilm Catalysts for Increased Cr(VI) Reduction

UV/FeⅡNTA as a novel photoreductive system for the degradation of perfluorooctane sulfonate (PFOS) via a photoinduced intramolecular electron transfer mechanism

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