A severe reduction in the cytochrome <scp>C</scp> content of <scp>G</scp>eobacter sulfurreducens eliminates its capacity for extracellular electron transfer

Estevez-Canales, Marta; Kuzume, Akiyoshi; Borjas, Zulema; Füeg, Michael; Lovley, Derek R.; Wandlowski, Thomas; Esteve‐Núñez, Abraham

doi:10.1111/1758-2229.12230

Cited by 71 publications

(52 citation statements)

References 69 publications

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“…This is possible owing to the high abundance of c‐ type cytochromes (more than 100 genes encode these redox proteins), most of which contain multiple heme groups that can act as electron transfer mediators and are exposed on the outermost membrane of the cell . Moreover, the culture of heme‐depleted cells has recently revealed that c‐ type cytochromes are the key for the interchange of electrons with an electrode . Therefore, the redox chemistry of Geobacter is mainly based on the chemistry of the heme group, which hosts an iron atom that can be reversibly reduced or oxidized.…”

Section: Introductionmentioning

confidence: 99%

The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion

et al. 2017

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We have explored a new concept in bacteria-electrode interaction based on the use of fluid-like electrodes and planktonic living cells. We show for the first time that living in a biofilm is not a strict requirement for Geobacter sulfurreducens to exchange electrons with an electrode. The growth of planktonic electroactive G. sulfurreducens could be supported by a fluid-like anode as soluble electron acceptors and with electron transfer rates similar to those reported for electroactive biofilms. This growth was maintained by uncoupling the charge (catabolism) and discharge (extracellular respiration) processes of the cells. Our results reveal a novel method to culture electroactive bacteria in which every single cell in the medium could be instantaneously wired to a fluid-like electrode. Direct extracellular electron transfer is occurring but with a new paradigm behind the bacteria-electrode interaction.

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Section: Introductionmentioning

confidence: 99%

The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion

et al. 2017

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“…Previous studies reported that cytochromes were localized to the outer membrane of the anaerobically grown cells of Shewanella and facilitated electron transfer from intact bacterial cells to electrodes (29, 35). One study also demonstrated that c -type cytochromes were essential for extracellular electron transfer by G. sulfurreducens and its electron-transferring ability depended on the content of cytochrome C (15). Thus, the results of the Raman microscopy analysis provided additional support along with the CV analysis for strain SCS5 being a potent electrochemically active bacterium.…”

Section: Discussionmentioning

confidence: 99%

Electrochemical Characterization of a Novel Exoelectrogenic Bacterium Strain SCS5, Isolated from a Mediator-Less Microbial Fuel Cell and Phylogenetically Related to Aeromonas jandaei

Sharma

Chen

et al. 2016

Microbes and environments

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A facultative anaerobic bacterium, designated as strain SCS5, was isolated from the anodic biofilm of a mediator-less microbial fuel cell using acetate as the electron donor and α-FeOOH as the electron acceptor. The isolate was Gram-negative, motile, and shaped as short rods (0.9–1.3 μm in length and 0.4–0.5 μm in width). A phylogenetic analysis of the 16S rRNA, gyrB, and rpoD genes suggested that strain SCS5 belonged to the Aeromonas genus in the Aeromonadaceae family and exhibited the highest 16S rRNA gene sequence similarity (99.45%) with Aeromonas jandaei ATCC 49568. However, phenotypic, cellular fatty acid profile, and DNA G+C content analyses revealed that there were some distinctions between strain SCS5 and the type strain A. jandaei ATCC 49568. The optimum growth temperature, pH, and NaCl (%) for strain SCS5 were 35°C, 7.0, and 0.5% respectively. The DNA G+C content of strain SCS5 was 59.18%. The isolate SCS5 was capable of reducing insoluble iron oxide (α-FeOOH) and transferring electrons to extracellular material (the carbon electrode). The electrochemical activity of strain SCS5 was corroborated by cyclic voltammetry and a Raman spectroscopic analysis. The cyclic voltammogram of strain SCS5 revealed two pairs of oxidation-reduction peaks under anaerobic and aerobic conditions. In contrast, no redox pair was observed for A. jandaei ATCC 49568. Thus, isolated strain SCS5 is a novel exoelectrogenic bacterium phylogenetically related to A. jandaei, but shows distinct electrochemical activity from its close relative A. jandaei ATCC 49568.

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“…0 V) in contrast with the typical value of ca. 0.2 V detected on standard graphite electrodes [7,36]. The shift in the oxidation potential might be related with graphene's better electric conductivity, which is several orders of magnitude higher than that of carbon [33].…”

Section: Screen-printed Electrodes (Spes): Testing Electroactivity Inmentioning

confidence: 94%

Screen-Printed Electrodes: New Tools for Developing Microbial Electrochemistry at Microscale Level

et al. 2015

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Abstract:Microbial electrochemical technologies (METs) have a number of potential technological applications. In this work, we report the use of screen-printed electrodes (SPEs) as a tool to analyze the microbial electroactivity by using Geobacter sulfurreducens as a model microorganism. We took advantage of the small volume required for the assays (75 µL) and the disposable nature of the manufactured strips to explore short-term responses of microbial extracellular electron transfer to conductive materials under different scenarios. The system proved to be robust for identifying the bioelectrochemical response, while avoiding complex electrochemical setups, not available in standard biotechnology laboratories. We successfully validated the system for characterizing the response of Geobacter sulfurreducens in different physiological states (exponential phase, stationary phase, and steady state under continuous culture conditions) revealing different electron transfer responses. Moreover, a combination of SPE and G. sulfurreducens resulted to be a promising biosensor for quantifying the levels of acetate, as well as for performing studies in real wastewater. In addition, the potential of the technology for identifying electroactive consortia was tested, as an example, with a mixed population with nitrate-reducing capacity. We therefore present SPEs as a novel low-cost platform for assessing microbial electrochemical activity at the microscale level.

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A severe reduction in the cytochrome C content of Geobacter sulfurreducens eliminates its capacity for extracellular electron transfer

Cited by 71 publications

References 69 publications

The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion

The Planktonic Relationship Between Fluid‐Like Electrodes and Bacteria: Wiring in Motion

Electrochemical Characterization of a Novel Exoelectrogenic Bacterium Strain SCS5, Isolated from a Mediator-Less Microbial Fuel Cell and Phylogenetically Related to <i>Aeromonas jandaei</i>

Screen-Printed Electrodes: New Tools for Developing Microbial Electrochemistry at Microscale Level

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