Periodic polarization of electroactive biofilms increases current density and charge carriers concentration while modifying biofilm structure

Zhang, Xu; Louro, Ricardo O.; Paquete, Catarina M.; Rabaey, Korneel

doi:10.1016/j.bios.2018.08.045

Cited by 61 publications

(71 citation statements)

References 59 publications

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“…Figure 6 clearly shows that for the experimental period, which lies within the turnover phase of the batch experiment, the currents that were achieved at constant potential for one hour do not show any signs of decline. Thus, capacitive storage effects as utilized in other recent studies [19,21] do not play a role. These two studies show an increase in steady state current densities at a constant applied potential generated by EAB previously operated/ cultivated under different transition times between open circuit potential and a single applied more positive potential vs. their internal controls.…”

Section: Experimental Validationmentioning

confidence: 76%

“…Maximum power point tracking as method typically falls between 1 and 2.2, however depending on the step (external resistance or potential) width and duration of application (∼scan rate) varying external resistance, linear sweep/cyclic voltammetry can become equivalent to 2.1. Fast transitions between two potentials yield intermittent enhancement of the current density by exploiting the redox capacitance of electrochemically active biofilms (and their cytochrome pool) ,,. Whether or not EAB are held in a charging state, resulting in a significant capacitive current response, is likely an important factor selecting which EAB and which EET pathways are established in a mature biofilm.…”

Section: Introductionmentioning

confidence: 99%

“…Polarization at alternating anode potentials 2.1. Fast transition or switching between two potentials [19][20][21] 2.2. Slow transition or scanning across a wide range of potentials [22] Maximum power point tracking as method typically falls between 1 and 2.2, [23] however depending on the step (external resistance or potential) width and duration of application (s can rate) varying external resistance, linear sweep/cyclic voltammetry can become equivalent to 2.1.…”

Section: Introductionmentioning

confidence: 99%

“…Fast transitions between two potentials yield intermittent enhancement of the current density by exploiting the redox capacitance of electrochemically active biofilms (and their cytochrome pool). [19,21,24] Whether or not EAB are held in a charging state, resulting in a significant capacitive current response, is likely an important factor selecting which EAB and which EET pathways are established in a mature biofilm.…”

Section: Introductionmentioning

confidence: 99%

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Cultivating Electrochemically Active Biofilms at Continuously Changing Electrode Potentials

et al. 2019

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In this study, electrochemically active microbial biofilms were cultivated and studied at continuously alternating electrode potentials. Compared to cultivation and operation at a single constant potential, this method enhanced microbial turnover and maximum current densities. Electrochemically active microbial biofilms were cultivated in a multi‐carbon source culture for several biofilm generations and were subsequently fed with real, domestic wastewater. Compared to constant potential cultivation, average (N=12) biofilm limiting current density at +0.2 V vs. Ag/AgCl increased from 0.350±0.101 to 0.508±0.099 mA cm−2 with a significant reduction in the time required until the maximum current output was reached from 2.01±0.79 to 1.36±0.71 d. The relative increase in maximum current density and decrease in the time required to reach it are similar. The relative differences of higher over lower values are both approximately 45 %. Biofilm community analysis showed a dominance of Geobacteraceae spp. in the electrochemically active biofilms, which is in accordance with the formal potentials derived from cyclic voltammetry. The overall increase in performance is related to the selection of electrochemically active microorganisms, which exhibit local maxima in their electron transfer kinetics between −0.3 and −0.2 V vs. Ag/AgCl.

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Section: Experimental Validationmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cultivating Electrochemically Active Biofilms at Continuously Changing Electrode Potentials

et al. 2019

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“…It was suggested that this could be attributed to an increased production of conductive features such as cytochrome or nanowire. We recently reported that the electroactive nature of Geobacter ‐dominated EABs can be tuned by applying periodic polarizations to the underlying electrode during the entire growth of the biofilm . In particular, applying an optimized periodic polarization (half‐periods of 10 s alternating open circuit potential (OCP) and polarizations at −0.1 V vs. Ag/AgCl) increased the maximum steady‐state catalytic current density up to 3‐times with respect to the continuously polarized controls (1.1 mA cm −2 vs. 0.4 mA cm −2 ).…”

Section: Introductionmentioning

confidence: 99%

Reversible Effects of Periodic Polarization on Anodic Electroactive Biofilms

2019

Self Cite

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Anodic electroactive biofilms (EABs) are commonly grown under continuous polarization of the underlying electrode. Their growth under appropriate periodic polarization was recently reported to considerably enhance their electrochemical properties (catalytic current and charge carriers concentration). This improvement was only investigated on relatively short term (ten days), and its resilience once the periodic polarizations are switched back to continuous (or vice versa) has not yet been assessed. Here, we first cultivated 16 Geobacter-dominated EABs on glassy carbon electrodes under either continuous or periodic polarization for several days. The polarization mode was then switched from continuous to periodic and vice versa. The improvement induced by the initial periodic polarization was lost over only two days of continuous polarization. Conversely, it took about ten days of periodic polarization to fully improve the electroactivity of the EABs initially grown under continuous polarization. The periodic polarization favored biofilm detachments, which were followed by a full recovery of current within three days. The performance of EABs under periodic polarization was less negatively impacted under substrate-limiting conditions, likely because of substrate replenishment during open circuit periods.

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Electroanalytical Techniques for Investigating Biofilms in Microbial Fuel Cells

Kumar

Basu

2019

Bioelectrochemical Interface Engineering

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Periodic polarization of electroactive biofilms increases current density and charge carriers concentration while modifying biofilm structure

Cited by 61 publications

References 59 publications

Cultivating Electrochemically Active Biofilms at Continuously Changing Electrode Potentials

Cultivating Electrochemically Active Biofilms at Continuously Changing Electrode Potentials

Reversible Effects of Periodic Polarization on Anodic Electroactive Biofilms

Electroanalytical Techniques for Investigating Biofilms in Microbial Fuel Cells

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