Membrane Separated Flow Cell for Parallelized Electrochemical Impedance Spectroscopy and Confocal Laser Scanning Microscopy to Characterize Electro-Active Microorganisms

Stöckl, Markus; Schlegel, Christin; Sydow, Anne; Holtmann, Dirk; Ulber, Roland; Mangold, Klaus‐Michael

doi:10.1016/j.electacta.2016.10.057

Cited by 24 publications

(16 citation statements)

References 34 publications

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“…Appendages produced by S. oneidensis could not be observed in SEM images. A monolayer of S. oneidensis cells on an electrode (indium tin coated cover glass) was also observed before …”

Section: Resultsmentioning

confidence: 99%

Adsorption of Shewanella oneidensis MR‐1 to the electrode material activated carbon fabric

Mayer

Stöckl

Krieg

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND Electroactive microorganisms generate current in microbial fuel cells by oxidizing organic compounds and transferring the electrons to an anode. Thereby the adsorption of cells to the electrode is the first step in the process of biofilm formation. RESULTS A comparison of different electrode materials showed that activated carbon fabric has the best cell adsorption properties for the simple and strong attachment of Shewanella oneidensis cells to the electrode material under aerobic and non‐electrochemical conditions. A preadsorbed anode (20 cm2) contained 18 mg of cell biomass (OD600 = 0.3) and reached a current density of 4.25 μA cm−2. Under anaerobic conditions the adsorption to the activated carbon fabric was much less, however the current density was with 6.5 μA cm−2 (OD600 = 0.3) and 7.75 μA cm−2 (OD600 = 0.9) higher as under aerobic adsorption conditions. CONCLUSION Activated carbon fabric is, due to its cell adsorption property and electrical conductivity, good for MFC applications. The material allows cell reproduction directly on the anode which is important for single‐ or multi‐layer biofilm formation. © 2018 Society of Chemical Industry

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“…Appendages produced by S. oneidensis could not be observed in SEM images. A monolayer of S. oneidensis cells on an electrode (indium tin coated cover glass) was also observed before …”

Section: Resultsmentioning

confidence: 99%

Adsorption of Shewanella oneidensis MR‐1 to the electrode material activated carbon fabric

Mayer

Stöckl

Krieg

et al. 2018

J of Chemical Tech & Biotech

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“…In addition, since those studies used batch-mode BESs (10,13,14), knowledge regarding electrochemically active biofilms formed under electrolyte-flow conditions is limited. Recent studies developed optically accessible electrochemical flow cells (EFCs) and used them to observe electrodeattached Shewanella cells during current generation (15,16); however, those studies did not observe the structures and compositions of mature biofilms that actively generated current under electrolyte-flow conditions.…”

mentioning

confidence: 99%

Structures, Compositions, and Activities of Live Shewanella Biofilms Formed on Graphite Electrodes in Electrochemical Flow Cells

Kitayama

Koga

Kasai

et al. 2017

Appl Environ Microbiol

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An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with MR-1 expressing an anaerobic fluorescent protein, and biofilm formation on the WE was observed over time during current generation at WE potentials of +0.4 and 0 V (versus standard hydrogen electrodes), under electrolyte-flow conditions. Electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.4-V biofilm. Microscopic analyses revealed that, in contrast to aerobic biofilms, current-generating biofilm (at +0.4 V) was thin and flat (∼10 μm in thickness), and cells were evenly and densely distributed in the biofilm. In contrast, cells were unevenly distributed in biofilm formed at 0 V. fluorescence staining and biofilm recovery experiments showed that the amounts of extracellular polysaccharides (EPSs) in the +0.4-V biofilm were much smaller than those in the aerobic and 0-V biofilms, suggesting that cells suppress the production of EPSs at +0.4 V under flow conditions. We suggest that cells perceive electrode potentials and modulate the structure and composition of biofilms to efficiently transfer electrons to electrodes. A promising application of microbial fuel cells (MFCs) is to save energy in wastewater treatment. Since current is generated in these MFCs by biofilm microbes under horizontal flows of wastewater, it is important to understand the mechanisms for biofilm formation and current generation under water-flow conditions. Although massive work has been done to analyze the molecular mechanisms for current generation by model exoelectrogenic bacteria, such as , limited information is available regarding the formation of current-generating biofilms over time under water-flow conditions. The present study developed electrochemical flow cells and used them to examine the electrochemical and structural features of current-generating biofilms under water-flow conditions. We show unique features of mature biofilms actively generating current, creating opportunities to search for as-yet-undiscovered current-generating mechanisms in biofilms. Furthermore, information provided in the present study is useful for researchers attempting to develop anode architectures suitable for wastewater treatment MFCs.

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“…It contains a 72 bp synthetic genomic integration that can be used for the quantification of cells via quantitative PCR (qPCR, see below). The gfp strain constitutively expresses a gfp gene and was used for fluorescence microcopy (Stöckl et al, 2016). All strains were pre-cultured under oxic conditions in LB medium at 30°C.…”

Section: Methodsmentioning

confidence: 99%

“…Experiments in the impedance flow cell were performed according to Stöckl et al (2016) in a previously described flow cell (40). The flow cell was modified by the addition of an Ag/AgCl reference electrode (RE-3VT, ALS, Tokyo, Japan) and assembled under sterile conditions.…”

Section: Methodsmentioning

confidence: 99%

Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms

et al. 2019

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Shewanella oneidensis is one of the best-understood model organisms for extracellular electron transfer. Endogenously produced and exported flavin molecules seem to play an important role in this process and mediate the connection between respiratory enzymes on the cell surface and the insoluble substrate by acting as electron shuttle and cytochrome-bound cofactor. Consequently, the addition of riboflavin to a bioelectrochemical system (BES) containing S. oneidensis cells as biocatalyst leads to a strong current increase. Still, an external application of riboflavin to increase current production in continuously operating BESs does not seem to be applicable due to the constant washout of the soluble flavin compound. In this study, we developed a recyclable electron shuttle to overcome the limitation of mediator addition to BES. Riboflavin was coupled to magnetic beads that can easily be recycled from the medium. The effect on current production and cell distribution in a BES as well as the recovery rate and the stability of the beads was investigated. The addition of synthesized beads leads to a more than twofold higher current production, which was likely caused by increased biofilm production. Moreover, 90% of the flavin-coupled beads could be recovered from the BESs using a magnetic separator.

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Membrane Separated Flow Cell for Parallelized Electrochemical Impedance Spectroscopy and Confocal Laser Scanning Microscopy to Characterize Electro-Active Microorganisms

Cited by 24 publications

References 34 publications

Adsorption of Shewanella oneidensis MR‐1 to the electrode material activated carbon fabric

Adsorption of Shewanella oneidensis MR‐1 to the electrode material activated carbon fabric

Structures, Compositions, and Activities of Live Shewanella Biofilms Formed on Graphite Electrodes in Electrochemical Flow Cells

Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms

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