Raba'atun Adawiyah Shamsuddin, W. Daud, Byung Hong Kim et al.

Sains Malaysiana • 2018

Microbial fuel cells (MFCs) have a high potential application for simultaneous wastewater treatment and electricity generation. However, the choice of the electrode material and its design is critical and directly affect their performance. As an electrode of MFCs, the anode material with surface modifications is an attractive strategy to improve the power output. In this study, stainless steel (SS) and carbon steel (CS) was chosen as a metal anode, while graphite felt (GF) was used as a common anode. Heat treatment was performed to convert SS, CS and GF into efficient anodes for MFCs. The maximum current density and power density of the MFC-SS were achieved up till 762.14 mA/m2 and 827.25 mW/m2, respectively, which were higher than MFC-CS (641.95 mA/m2 and 260.14 mW/m2) and MFC-GF (728.30 mA/m2 and 307.89 mW/m2). Electrochemical impedance spectroscopy of MFC-SS showed better catalytic activity compared to MFC-CS and MFC-GF anode, also supported by cyclic voltammetry test.

Yulia V. Plekhanova, S. Tarasov, A. Bykov et al.

IET Nanobiotechnology • 2019

This work considers the effects of various carbon nanomaterials and fibres on bioelectrocatalytic and respiratory activity of bacterial cells during the oxidation of ethanol in the presence of an electron transport mediator. Gluconobacter oxydans sbsp. industrius VKM B-1280 cells were immobilised on the surfaces of graphite electrodes and had an adsorption contact with a nanomaterial (multi-walled carbon nanotubes, thermally expanded graphite, highly oriented pyrolytic graphite, graphene oxide, reduced graphene oxide). The electrochemical parameters of the electrodes (the polarisation curves, the value of generated current at the introduction of substrate, the impedance characteristics) were measured in two-electrode configuration. Modification by multi-walled carbon nanotubes led to the increase of microbial fuel cell (MFC) electric power by 26%. The charge transfer resistance of modified electrodes was 47% lower than unmodified ones. Thermally expanded and pyrolytic graphites had a slight negative effect on the electrochemical properties of modified electrodes. The respiratory activity of bacterial cells did not change in the presence of nanomaterials. The data can be used in the development of microbial biosensors and MFC electrodes based on Gluconobacter cells.

D. Strik, A. Heijne, H. Hamelers et al.

ECS Transactions • 2008

Electrochemical impedance spectroscopy (EIS) is in potential a powerful tool for the in depth analysis of microbial fuels cells (MFCs). To prevent the risk of drawing false conclusions from invalid EIS measurements we investigated the feasibility of this method on an MFC by checking: linearity, causality, stability and finiteness. EIS application under steady state conditions was partly feasible. For further application EIS on MFCs we recommend to: (1) use the constant anode or cathode potential measurement mode with a fast couple at the counter electrode; (2) record the polarization curve and measure at different amplitudes to check the linearity condition; (3) perform preliminary measurements to reveal measurement presets; (4) apply prolonged pretreatment to facilitate the stability criterion; (5) perform duplicate measurements to examine the stability; (6) use a broad frequency range to validate the finiteness criterion; (7) use a statistical based validation check based on the Kramers-Kronig transformation.

Chao Li, K. Zhou, Hanyue He et al.

International Journal of Environmental Research and Public Health • 2020

The low power generation efficiency of microbial fuel cells (MFCs) is always a barrier to further development. An attempt to enhance the start-up and electricity generation of MFCs was investigated by adding different doses of zero-valent iron into anaerobic anode chambers in this study. The results showed that the voltage (289.6 mV) of A2 with 0.5 g of zero-valent iron added was higher than the reference reactor (197.1 mV) without dosing zero-valent iron (A4). The maximum power density of 27.3 mW/m2 was obtained in A2. CV analysis demonstrated that A2 possessed a higher oxidation–reduction potential, hence showing a stronger oxidizing property. Meanwhile, electrochemical impedance analysis (EIS) also manifested that values of RCT of carbon felts with zero-valent iron supplemented (0.01–0.03 Ω) were generally lower. What is more, SEM images further proved and illustrated that A2 had compact and dense meshes with a hierarchical structure rather than a relatively looser biofilm in the other reactors. High-throughput sequencing analysis also indicated that zero-valent iron increased the abundance of some functional microbial communities, such as Acinetobacter, Ignavibacteriales, Shewanella, etc.

A. Borole, D. Aaron, C. Hamilton et al.

Environmental Science & Technology • 2010

Changes in the anode, cathode, and solution/membrane impedances during enrichment of an anode microbial consortium were measured using electrochemical impedance spectroscopy. The consortium was enriched in a compact, flow-through porous electrode chamber coupled to an air-cathode. The anode impedance initially decreased from 296.1 to 36.3 Omega in the first 43 days indicating exoelectrogenic biofilm formation. The external load on the MFC was decreased in a stepwise manner to allow further enrichment. MFC operation at a final load of 50 Omega decreased the anode impedance to 1.4 Omega, with a corresponding cathode and membrane/solution impedance of 12.1 and 3.0 Omega, respectively. An analysis of the capacitive element suggested that most of the three-dimensional anode surface was participating in the bioelectrochemical reaction. The power density of the air-cathode MFC stabilized after 3 months of operation and stayed at 422 +/- 42 mW/m(2) (33 W/m(3)) for the next 3 months. The normalized anode impedance for the MFC was 0.017 kOmega cm(2), a 28-fold reduction over that reported previously. This study demonstrates a unique ability of biological systems to reduce the electron transfer resistance in MFCs, and their potential for stable energy production over extended periods of time.

V. H. Guadarrama-Pérez, P. Mijaylova-Nacheva, G. Moeller-Chavez et al.

Biofuels • 2023

Abstract Microbial fuel cells (MFC) have attracted the attention of scientists due to their capacity to improve electricity production and to employ wastewater as substrate. This duality results in a source of clean energy and degradation of the organic matter. The use of catalysts such as platinum make the implementation of these technologies difficult, therefore, it is a challenge to find economically feasible options and strategies carry out studies. Stream sediments (SS) and anaerobic granular sludge (AGS) were compared in a single chamber-MFC. Reactors constructed with Plexiglas contained carbon cloth cathode treated with polystyrene, graphite felt anode, and acetate as substrates. The voltage was measured with a digital multimeter, whereas power density and Coulombic efficiency were calculated based on Ohm’s law. The electrochemistry impedance spectroscopy analysis was determined with an equivalent circuit model resistances. AGS-MFC produced 1.35 mW/m2 and 30 mA/m2, while SS-MFC produced 1.25 mW/m2 and 20 mA/m2 of power density and current density, respectively. AGS-MFC showed a 10% greater Coulombic efficiency compared to the one obtained from the SS-MFC. In this research, the effect of the inoculum on power density in an MFC was evaluated with the objective of finding sources of microorganisms with better capacities for electricity production and organic matter degradation. The equivalent circuit model showed that AGS-MFC obtained the lowest charge transfer resistance value and the highest constant phase elements values. AGS was the inoculum that showed the best performance in the MFC in terms of voltage and power density.

A. Tabish, Iqra Farhat, M. Irshad et al.

Energies • 2023

Microbial fuel cell (MFC) technology is anticipated to be a practical alternative to the activated sludge technique for treating domestic and industrial effluents. The relevant literature mainly focuses on developing the systems and materials for maximum power output, whereas understanding the fundamental electrochemical characteristics is inadequate. This experimental study uses a double-chamber MFC having graphite electrodes and an anion-exchange membrane to investigate the electrochemical process limitations and the potential of bioelectricity generation and dairy effluent treatment. The results revealed an 81% reduction in the chemical oxygen demand (COD) in 10 days of cell operation, with an initial COD loading of 4520 mg/L. The third day recorded the highest open circuit voltage of 396 mV, and the maximum power density of 36.39 mW/m2 was achieved at a current density of 0.30 A/m2. The electrochemical impedance spectroscopy analysis disclosed that the activation polarization of the aerated cathode was the primary factor causing the cell’s resistance, followed by the ohmic and anodic activation overpotentials.

Yiwei Han, Jingyuan Wang, Liming Jiang et al.

Coatings • 2025

Microbial Fuel Cell (MFC) is a novel bioelectrochemical system that catalyzes the oxidation of chemical energy in organic waste and converts it directly into electrical energy through the attachment and growth of electroactive microorganisms on the electrode surface. This technology realizes the synergistic effect of waste treatment and renewable energy production. A CF-NiO-PANI capacitor composite anode was prepared by loading polyaniline on a CF-NiO electrode to improve the capacitance of a CF electrode. The electrochemical characteristics of the composite anode were evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the electrode materials were analyzed comprehensively by scanning electron microscopy (SEM), energy diffusion spectrometer (EDS), and Fourier transform infrared spectroscopy (FTIR). MFC system based on CF-NiO-PANI composite anode showed excellent energy conversion efficiency in potato starch wastewater treatment, and its maximum power density increased to 0.4 W/m3, which was 300% higher than that of the traditional CF anode. In the standard charge–discharge test (C1000/D1000), the charge storage capacity of the composite anode reached 2607.06 C/m2, which was higher than that of the CF anode (348.77 C/m2). Microbial community analysis revealed that the CF-NiO-PANI anode surface formed a highly efficient electroactive biofilm dominated by electrogenic bacteria (accounting for 47.01%), confirming its excellent electron transfer ability. The development of this innovative capacitance-catalytic dual-function anode material provides a new technical path for the synergistic optimization of wastewater treatment and energy recovery in MFC systems.

G. Bampos, Zoe Gargala, Ilias Apostolopoulos et al.

Processes • 2024

In the present work, four different wastewaters from the food industry were used in parallel, in four identical dual-chamber MFCs, with graphite granules as anodic electrodes. Specifically, a mixture of hydrogenogenic reactor effluents (effluents from a dark fermentation reactor fed with cheese whey (CW), for hydrogen production), CW, and a mixture of expired fruit juices and wastewater from the confectionery industry were simultaneously used in MFCs to evaluate the effect of the type of effluent/wastewater on their efficiency. An electrochemical characterization was performed using electrochemical impedance spectroscopy measurements under open- (OCP) and closed-circuit conditions, at the beginning and end of the operating cycle, and the internal resistances were determined and compared. The results showed that the highest OCP value, as well as the highest power density (Pmax) and Coulombic efficiency (εcb) at the beginning of the operating cycle, was exhibited by the MFC, using a sugar-rich wastewater from the confectionery industry as substrate (sugar accounts for almost 92% of the organic content). This can be correlated with the low internal resistance extracted from the Nyquist plot at OCP. In contrast, the use of CW resulted in a lower performance in terms of OCP, εcb and Pmax, which could be correlated to the high internal resistance and the composition of CW, a substrate rich in lactose (disaccharide), and which also contains other substances (sugars account for almost 72% of its organic content, while the remaining 28% is made up of other soluble compounds).

Yan Yang, Q. Shen

Polish Journal of Environmental Studies • 2019

To explore the remediation feasibility of heavy metal pollution in wetland soil using a plantmicrobial fuel cell (P-MFC) and the corresponding mechanism, a P-MFC system was constructed with in situ simulations of real wetland environment. By using Typhalatifolia L. as the trial plant, the electrochemical properties of the anode under different cadmium (Cd) concentrations are analyzed by cyclic voltammetry and electrochemical impedance, and the microbial community structure is determined by high-throughput sequencing. The maximum P-MFC output voltage of 546.65 mV and Cd accumulation of 36.461 mg/kg at the Typhalatifolia L. roots are revealed. Cd stress could not only decrease the output voltage and anodic electrochemical activity of the P-MFC system but also affect the accumulation ability of Typhalatifolia L. and the internal resistance and microbial community structure of P-MFC. We find it feasible to apply P-MFC to large-scale heavy metal remediation in wetland soil, but it is critical to consider the tolerance range of pollution stress to achieve the best balance between energy output and environmental restoration.

S. Chevalier, Marine Garcia, A. Sommier et al.

arXiv (Cornell University) • 2022

In this paper we report a semianalytical model of the mass transfer impedance in microfluidic electrochemical chips (MEC). It is based on the molar advection diffusion equation in a microfluidic channel with a Poiseuille flow and an electrochemical reaction at the interface of deposited electrodes. Using the Fourier-Laplace integral transforms and the quadrupole formalism, a solution to these equations is found and the three dimensional (3D) transient concentration and current density fields are computed. This solution is validated using MFC operando concentration fields measured by visible spectroscopic imaging technique, and several equivalent electrical circuits are also proposed to model the mass transfer in MEC. This work reports the fastest way to compute the 3D transient mass transfer impedance which can be used in large variety of applications such as MEC based cytometry measurements or fuel cell current density prediction.

S. Venkata Ramana, Cristina M. Cordas, Sara C. Matias et al.

Research Square • 2020

Abstract In the present work the electrochemical behaviour of microbial cells from a biocathode microbial fuel cell (MFC) functioning with wastewater was evaluated by cyclic voltammetry. In-situ electrochemical assays were performed and, under the tested experimental conditions, the biocathode medium was found to be the most efficient for the cathodic catalysed electrochemical reduction of oxygen. Different controls using sterile media and membranes covering the electrodes were performed and compared with the regular biocathode results. In the biocathode chamber, the presence of bacteria was associated with the enhanced active redox processes and with the higher electrochemical reduction of oxygen activity. The present study is a contribution to the understanding of the viability and advantages of the biocathodes use in MFC.

Maria Essa, Saima Mehar, Haneef Ur Rehman

Research Square • 2024

Abstract Microbial fuel cell (MFC) technology offers an innovative and sustainable solution for energy production, particularly in electricity-deprived regions. This study focuses on the design of a microbial biofuel cell that utilizes S. cerevisiae to generate bioelectricity from fisheries wastewate through bio-elecrochemical reaction. The MFC system harnesses electrons released during biochemical reactions catalyzed by microorganisms. Optimization of physical parameters was performed to maximize bioelectricity generation from fisheries wastewater. The results revealed that S. cerevisiae -based MFC achieved the highest bioelectricity production at 35 ºC, pH 8, and an incubation period of 72 hours. To enhance performance, a flow rate of 50 mL/min of oxygen in the wastewater was found to be the most effective for bioelectricity generation. The findings demonstrate the practicality and sustainability of the S. cerevisiae-based MFC as a viable technique for both bioelectricity production and wastewater management in the fisheries industry. This innovative approach not only addresses the basic electricity needs of electricity-deprived regions but also helps mitigate wastewater pollution, presenting an environmentally friendly solution. The study highlights the potential of MFC technology to contribute to renewable energy generation and environmental sustainability in regions reliant on fisheries wastewater.

Basem S. Zakaria, Bipro Ranjan Dhar

bioRxiv (Cold Spring Harbor Laboratory) • 2020

Abstract The microbial electrolysis cell assisted anaerobic digestion (MEC-AD) holds great promises over conventional anaerobic digestion. This article reports an experimental investigation of extracellular polymeric substances (EPS), reactive oxygen species (ROS), and the expression of genes associated with extracellular electron transfer (EET) in methanogenic biocathodes. The MEC-AD systems were examined using two cathode materials: carbon fibers and stainless-steel mesh. A higher abundance of hydrogenotrophic Methanobacterium sp. and homoacetogenic Acetobacterium sp. appeared to play a major role in superior methanogenesis from stainless steel biocathode than carbon fibers. Moreover, the higher secretion of EPS accompanied by the lower ROS level in stainless steel biocathode indicated that higher EPS perhaps protected cells from harsh metabolic conditions (possibly unfavorable local pH) induced by faster catalysis of hydrogen evolution reaction. In contrast, EET-associated gene expression patterns were comparable in both biocathodes. Thus, these results indicated hydrogenotrophic methanogenesis is the key mechanism, while cathodic EET has a trivial role in distinguishing performances between two cathode electrodes. These results provide new insights into the efficient methanogenic biocathode development.

Pei Zhang

ECS Meeting Abstracts • 2017

A novel microorganism of Bioechem proprietary, named P1, promotes high electron transport activity on cathode, shown as the highest cathodic current output than the other reported microorganisms. A biocathode, using P1 as catalyst, was tested in an electrochemical system and showed enhanced performance than abiotic cathode. The performance of the biocathode was further improved through the microbial-electrode surface modification by reducing total free energy of the system for better sorption of the bacteria cells on to the electrode; providing more bacteria sorption sites on surface of the electrode; And adjusting the dissolved oxygen concentration on bacteria-electrode interface for faster bacteria metabolic rate and electron transfer rate. With the enhanced properties of the biocathode, the microorganisms can promote the on site energy supply 10 times or more. The biocathode was also first time applied into a primary battery setup and showed promising capacity and durability compare to a same size battery setup using abiotic electrodes and traditional chemical electrolyte.

Szymon Buchaniec, M. Gnatowski, H. Hasegawa et al.

Energies • 2023

Solid oxide fuel cells are becoming increasingly important in various applications, from households to large-scale power plants. However, these electrochemical energy conversion devices have complex behavior that is difficult to understand and optimize. A numerical simulation is a primary tool for analysis and optimization-design. One of the most significant challenges in this field is improving microscale transport phenomena and electrode reaction models. Two main categories of simulation are black-box and white-box models. The former requires large experimental datasets and lacks physical constraints, while the latter inherits the inaccuracy of typical electrochemical reaction models. Here we show a micro-scale artificial neural network-supported numerical simulation that allows for overcoming those issues. In our research, we substituted one equation in the system, an electrochemical model, with an artificial neural network prediction. The data-driven prediction is constrained and must satisfy all reminded balance equations in the system. The results show that the proposed model can simulate an anode-electrode’s thermodynamic losses with improved accuracy compared with the classical approach. The coefficient of determination R2 for the proposed model was equal to 0.8810 for 800 °C, 0.8720 for 900 °C, and 0.8436 for 1000 °C. The findings open a way for improving the accuracy and computational complexity of electrochemical models in solid oxide fuel cell simulations.

Timothy T. Yang, W. Saidi

The Journal of Physical Chemistry Letters • 2022

The volcano trend has been widely utilized to forecast new optimum catalysts in computational chemistry while the Butler-Volmer relationship is the norm to explain current-potential characteristics from cyclic voltammetry in analytical chemistry. Herein, we develop an electrochemical model for hydrogen evolution reaction exchange currents that reconciles device-level chemistry, atomic-level volcano trend, and the Butler-Volmer relation. We show that the model is a function of the easy-to-compute hydrogen adsorption energy invariably obtained from first-principles atomic simulations. In addition, the model reproduces with high fidelity the experimental exchange currents for elemental metal catalysts over 15 orders of magnitude and is consistent with the recently proposed analytical model based on a data-driven approach. Our findings based on fundamental electrochemistry principles are general and can be applied to other reactions including CO2 reduction, metal oxidation, and lithium (de)intercalation reactions.

T. Yamahigashi, J. Shimura, K. Shibuya et al.

2023 11th International Conference on Power Electronics and ECCE Asia (ICPE 2023 - ECCE Asia) • 2023

An equivalent circuit model of lithium-ion batteries which has a nonlinear resistor governed by Butler-Volmer’s equation and a constant phase element was investigated. The current dependence of the real battery could be reproduced well by the contribution of the nonlinear resistor, and the transient response of voltage could be reproduced well by the contribution of the constant phase element.

Clifford M. Krowne

International Journal of Quantum Chemistry • 2023

The vanadium redox flow battery has been intensively examined since the 1970s. What is missing is a connection between the current‐overpotential Butler‐Volmer equation, which provides an extremely helpful starting point for analytical and numerical studies, and microscopic quantum mechanical behavior at the atomic level. Such a connection will allow further advancements beyond the macroscopic, though very useful and insightful, modeling already done in the literature. Here we show rigorously the connection between the Butler‐Volmer transfer coefficients, and the Marcus Gibbs free energy quantum mechanical parameters, and develop the equation directly in terms of the quantum mechanical parameters.

Robert Morasch, H. Gasteiger, Bharatkumar Suthar

Journal of The Electrochemical Society • 2023

The expression for the exchange current density to describe the intercalation kinetics of Li-ion battery materials proposed by Newman and coworkers has been used extensively for battery modeling, however its applicability to existing battery materials should be validated. Here we show an electrochemical impedance spectroscopy (EIS) analysis of the kinetic behavior of NCM 111 as a function of electrolyte salt concentration and state-of-charge (SOC) and compare it to the proposed theory. An areal capacity dependent EIS analysis first gives insights into the feasibility of measuring kinetic and transport parameters, including the solid diffusion resistance of lithium, showing that low-areal capacity electrodes are required to predominantly probe the kinetics. We then show how the charge transfer kinetics follow a Butler-Volmer type concentration dependent behavior for lower concentrated electrolytes (≤1.5 M) but deviate from the proposed theory at higher salt concentrations. A further SOC dependent analysis shows how NCM 111 generally follows the proposed theory of U-shaped symmetric kinetics, but the limited oxidative stability window leads to practically asymmetric kinetics for charging and discharging. This asymmetry is visible in NCM 111 lithiation and delithiation rate tests, where upon lithiation the kinetics generally become slower for higher degrees of lithiation, limiting the performance.

B. Paneru, Biplov Paneru, Nitish Pandey et al.

International Journal of Informatics, Information System and Computer Engineering (INJIISCOM) • 2024

For the analysis of  Proton Exchange Membrane Fuel Cell (PEMFC’s) efficiency, the Nernst equation and Butler-Volmer's concepts were used. The mathematical models using both equations were developed in MATLAB and compiled. The results generated by the output current based on the input parameters of the experimental data were compared with the experimental results for the two modelled PEMFCs. The parameters temperature, pressure, hydrogen concentration, and oxygen concentration at different values of external resistance were used to determine the change in output current in both models built in MATLAB. This sensitivity analysis generated negative output current values and highly dissimilar values with the experimental results for the same input parameters for both models due to the less use of input parameters in the model. The results showed that the PEMFC's performance is affected by most parameters, and many influencing parameters must be used to develop a perfect mathematical model of the PEMFC.        

D. N. Buckley, Johna Leddy

Journal of The Electrochemical Society • 2024

We revisit the classical derivation of the Butler-Volmer equation to include the effect of the electrode metal. If the metal is replaced by one with a different work function, keeping other conditions in the electrode constant, the chemical potential of electrons μ_e and the Galvani potential φ change in a complementary manner. Changes in μ_e and φ each impact the free energies of activation of the forward and backward electron transfer reactions, so we modify the classical expressions which relate them to applied voltage E by including also the effect of μ_e. Inserting these expressions in an Eyring-Polyani or Arrhenius type equation in the traditional way, we obtain a modified Butler-Volmer equation which expresses current density as a function of both E and Δμ_e. The exchange current density j_0 appears as an exponential function of Δμ_e. For the work function Φ of the metal, the approximation Δμ_e≈-FΔΦ yields a linear relationship between ln⁡〖j_0 〗 and Φ. The linear increase in ln⁡〖j_0 〗 with Φ has long been reported. We show two experimental examples: the aqueous Fe2+/Fe3+ couple with positive slope and the hydrogen evolution reaction (HER) with parallel lines for the d and sp metals, both with positive slopes.

N. Stein, H. Hamelers, G. van Straten et al.

Biosensors • 2012

Polarization curves are of paramount importance for the detection of toxic components in microbial fuel cell (MFC) based biosensors. In this study, polarization curves were made under non-toxic conditions and under toxic conditions after the addition of various concentrations of nickel, bentazon, sodiumdodecyl sulfate and potassium ferricyanide. The experimental polarization curves show that toxic components have an effect on the electrochemically active bacteria in the cell. (Extended) Butler Volmer Monod (BVM) models were used to describe the polarization curves of the MFC under nontoxic and toxic conditions. It was possible to properly fit the (extended) BVM models using linear regression techniques to the polarization curves and to distinguish between different types of kinetic inhibitions. For each of the toxic components, the value of the kinetic inhibition constant Ki was also estimated from the experimental data. The value of Ki indicates the sensitivity of the sensor for a specific component and thus can be used for the selection of the biosensor for a toxic component.

L. Zhao, J. Brouwer, J. Naviaux et al.

ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology • 2014

Microbial fuel cells (MFCs) are promising for simultaneous treatment of wastewater and energy production. In this study, a mathematical model for microbial fuel cells with air cathodes was developed and demonstrated by integrating biochemical reactions, Butler-Volmer expressions and mass/charge balances. The model developed is focused on describing and understanding the steady-state polarization curves of the microbial fuel cells with various levels and methods of anode-biofilm growth with air cathodes. This polarization model combines enzyme kinetics and electrochemical kinetics, and is able to describe measured polarization curves for microbial fuel cells with different anode-biofilm growth. The MFC model developed has been verified with the experimental data collected. The simulation results provide insights into the limiting physical, chemical and electrochemical phenomena and their effects on cell performance. For example, the current MFC data demonstrated performance primarily limited by cathode electrochemical kinetics.

Ahmed Y. Radeef, Z. Ismail

International Journal of Green Energy • 2021

ABSTRACT Potato chips processing industry generally discharge large volumes of organic loaded-wastewater and significant amounts of peels as solid wastes. In this study, a dual chamber microbial fuel cell (MFC) was setup, and continuously operated for 120 days for combined biotreatment of potato chips processing wastewater (PCW) and waste potato peels (PP) associated with electricity generation. The discarded PP were dried, grinded, and added to the PCW as a powder at concentrations of 0, 2.5, and 5 g PP/L resulted in three different organic loadings, denoted as OL0, OL1, and OL2, respectively. The results demonstrated significant removal efficiency of COD up to 99% with maximum power generation of 612.5, 800, and 1012.5 mW/m3 for OL0, OL1, and OL2, respectively. Butler–Volmer–Monod model was proposed to describe the overpotential-polarization curve for the MFC. Significant agreement was observed between the predicated and experimental results with determination coefficient (R2) values > 0.91.

T. Kamperidis, A. Tremouli, Antonis Peppas et al.

Energies • 2022

Bioelectrochemical systems have been the focus of extensive research due to their unique advantages of converting the chemical energy stored in waste to electricity. To acquire a better understanding and optimize these systems, modelling has been employed. A 2D microbial fuel cell (MFC) model was developed using the finite element software Comsol Multiphysics® (version 5.2), simulating a two-chamber MFC operating in batch mode. By solving mass and charge balance equations along with Monod–Butler–Volmer kinetics, the operation of the MFC was simulated. The model accurately describes voltage output and substrate consumption in the MFC. The computational results were compared with experimental data, thus validating the model. The voltage output and substrate consumption originating from the model were in agreement with the experimental data for two different cases (100 Ω, 1000 Ω external resistances). A polarization curve was extracted from the model by shifting the external resistance gradually, calculating a similar maximum power (47 mW/m2) to the observed experimental one (49 mW/m2). The validated model was used to predict the MFC response to varying initial substrate concentrations (0.125–4 g COD/L) and electrolyte conductivity (0.04–100 S/m) in order to determine the optimum operating conditions.

Stephen D. Springer, Alison Butler

ChemInform • 2016

Abstract Review: 99 refs.

Moriah Sandy, Alison Butler

ChemInform • 2010

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Orpheus Butler, Stefano Manzoni, Charles Warren

• 2025

Intracellular storage of carbon (C) by soil micro-organisms is emerging as a key process that influences soil biogeochemical cycling and the broader function of terrestrial ecosystems. One likely role of intracellular C storage is to serve as a stoichiometric buffer against nutritional imbalances in the microbial substrate. Such a function would make storage compounds vital to the long-term function of ecosystems associated with strongly weathered, low fertility soils, yet there have been few studies of intracellular carbon storage in such ecosystems. We examined the dynamics of two putative storage compounds (triacylglycerol [TAG] and polyhydroxybutyrate [PHB]) across two natural soil fertility gradients in eastern Australia. Across all sites and samples, absolute quantities of storage compounds ranged from 0 to 173 µg C g soil-1 in the case of TAG and 0 to 56 µg C g soil-1 for PHB. When standardized to total soil organic C, quantities of storage compounds tended to be markedly higher than those observed in prior studies of temperate and/or agricultural soils. Allocation to storage compounds followed strong trends across natural gradients of soil fertility and tended to peak in phosphorus-deficient and/or retrogressive ecosystems. Across soils of differing parent material, allocation to C storage was highest in infertile soils derived from phosphorus-depleted sandstone and ironstone compared to soils derived from shale and basalt. Likewise, allocation to C storage increased throughout ~700k years of soil development across a strongly weathered podzolic dune chronosequence. Dynamics of community-level C storage allocation were evidently underpinned by a combination of assemblage-level processes, most notably changes in the relative abundance of TAG-rich, C-limited fungal taxa, and physiological plasticity on the level of individual P-limited bacterial cells. Our findings are largely consistent with the surplus/reserve storage framework and highlight the importance of storage compounds for the function of oligotrophic ecosystems and as a major pool of C in soil.

Pam Engelberts, Jun Ye, Donovan Parks et al.

Research Square • 2024

Abstract Fluorescence in situ hybridisation (FISH) is a powerful tool for visualising the spatial organisation of microbial communities. However, traditional FISH has several limitations, including ​​limited phylogenetic resolution, difficulty visualising certain lineages​,​ ​​and the​​ design and optimis​ation of​ new probes is time consuming and does not scale​ to the ​known​ diversity of microbial life. Here, we present GenomeFISH, a high-throughput, genome-based FISH approach that can differentiate strains within complex communities. Fluorescent probes are generated from the genomes of single cells, which are ​obtained ​from environmental or clinical samples through fluorescence activated single-cell sorting (FACS). GenomeFISH can ​distinguish between ​strains with up to 99% average nucleotide identity and was successfully applied to visualise strains in mock communities and human faecal samples. Given the superior sensitivity and specificity of GenomeFISH, we envisage it will become the gold standard in the visualisation of complex microbial systems.

Stacey Butler, James O’Dwyer

bioRxiv (Cold Spring Harbor Laboratory) • 2018

Abstract Competition and mutualism are inevitable processes in microbial ecology, and a central question is which and how many taxa will persist in the face of these interactions. Ecological theory has demonstrated that when direct, pairwise interactions among a group of species are too numerous, or too strong, then the coexistence of these species will be unstable to any slight perturbation. This instability worsens when mutualistic interactions complement competition. Here, we refine and to some extent overturn that understanding, by considering explicitly the resources that microbes consume and produce. In contrast to more complex organisms, microbial cells consume primarily abiotic resources, and mutualistic interactions are often mediated by these same abiotic resources through the mechanism of cross-feeding. Our model therefore considers the consumption and production of a set of abiotic resources by a group of microbial species. We show that if microbes consume, but do not produce resources, then any positive equilibrium will always be stable to small perturbations. We go on to show that in the presence of crossfeeding, stability is no longer guaranteed. However, stability still holds when mutualistic interations are either symmetric, or sufficiently weak.

Stacey Butler, James P. O’Dwyer

Nature Communications • 2018

Abstract Competition and mutualism are inevitable processes in microbial ecology, and a central question is which and how many taxa will persist in the face of these interactions. Ecological theory has demonstrated that when direct, pairwise interactions among a group of species are too numerous, or too strong, then the coexistence of these species will be unstable to any slight perturbation. Here, we refine and to some extent overturn that understanding, by considering explicitly the resources that microbes consume and produce. In contrast to more complex organisms, microbial cells consume primarily abiotic resources, and mutualistic interactions are often mediated through the mechanism of crossfeeding. We show that if microbes consume, but do not produce resources, then any positive equilibrium will always be stable to small perturbations. We go on to show that in the presence of crossfeeding, stability is no longer guaranteed. However, positive equilibria remain stable whenever mutualistic interactions are either sufficiently weak, or when all pairs of taxa reciprocate each other’s assistance.

T. Chung, B. Dhar

Frontiers in Energy Research • 2021

For the past two decades, many successful applications of microbial electrochemical technologies (METs), such as bioenergy generation, environmental monitoring, resource recovery, and platform chemicals production, have been demonstrated. Despite these tremendous potentials, the scaling-up and commercialization of METs are still quite challenging. Depending on target applications, common challenges may include expensive and tedious fabrication processes, prolonged start-up times, complex design requirements and their scalability for large-scale systems. Incorporating the three-dimensional printing (3DP) technologies have recently emerged as an effective and highly promising method for fabricating METs to demonstrate power generation and biosensing at the bench scale. Notably, low-cost and rapid fabrication of complex and miniaturized designs of METs was achieved, which is not feasible using the traditional methods. Utilizing 3DP showed tremendous potentials to aid the optimization of functional large-scale METs, which are essential for scaling-up purposes. Moreover, 3D-printed bioanode could provide rapid start-up in the current generation from METs without any time lags. Despite numerous review articles published on different scientific and applied aspects of METs, as per the authors’ knowledge, no published review articles explicitly highlighted the applicability and potential of 3DP for developing METs. Hence, this review targets to provide a current overview and status of 3DP applications for advancing METs and their future outlook.

A. Karbelkar, E. Reynolds, Rachel Ahlmark et al.

ACS Central Science • 2021

Organophosphate (OP) pesticides cause hundreds of illnesses and deaths annually. Unfortunately, exposures are often detected by monitoring degradation products in blood and urine, with few effective methods for detection and remediation at the point of dispersal. We have developed an innovative strategy to remediate these compounds: an engineered microbial technology for the targeted detection and destruction of OP pesticides. This system is based upon microbial electrochemistry using two engineered strains. The strains are combined such that the first microbe (E. coli) degrades the pesticide, while the second (S. oneidensis) generates current in response to the degradation product without requiring external electrochemical stimulus or labels. This cellular technology is unique in that the E. coli serves only as an inert scaffold for enzymes to degrade OPs, circumventing a fundamental requirement of coculture design: maintaining the viability of two microbial strains simultaneously. With this platform, we can detect OP degradation products at submicromolar levels, outperforming reported colorimetric and fluorescence sensors. Importantly, this approach affords a modular, adaptable strategy that can be expanded to additional environmental contaminants.

M. de la Fuente, Carlos Gallardo-Bustos, R. De la Iglesia et al.

International Journal of Environmental Research and Public Health • 2022

For many years, the world’s coastal marine ecosystems have received industrial waste with high nitrogen concentrations, generating the eutrophication of these ecosystems. Different physicochemical-biological technologies have been developed to remove the nitrogen present in wastewater. However, conventional technologies have high operating costs and excessive production of brines or sludge which compromise the sustainability of the treatment. Microbial electrochemical technologies (METs) have begun to gain attention due to their cost-efficiency in removing nitrogen and organic matter using the metabolic capacity of microorganisms. This article combines a critical review of the environmental problems associated with the discharge of the excess nitrogen and the biological processes involved in its biogeochemical cycle; with a comparative analysis of conventional treatment technologies and METs especially designed for nitrogen removal. Finally, current METs limitations and perspectives as a sustainable nitrogen treatment alternative and efficient microbial enrichment techniques are included.

Anusha Ganta, Yasser Bashir, Sovik Das

Energies • 2022

A milk-processing plant was drafted as a distinctive staple industry amid the diverse field of industries. Dairy products such as yogurt, cheese, milk powder, etc., consume a huge amount of water not only for product processing, but also for sanitary purposes and for washing dairy-based industrial gear. Henceforth, the wastewater released after the above-mentioned operations comprises a greater concentration of nutrients, chemical oxygen demand, biochemical oxygen demand, total suspended solids, and organic and inorganic contents that can pose severe ecological issues if not managed effectively. The well-known processes such as coagulation–flocculation, membrane technologies, electrocoagulation, and other biological processes such as use of a sequencing batch reactor, upflow sludge anaerobic blanket reactor, etc., that are exploited for the treatment of dairy effluent are extremely energy-exhaustive and acquire huge costs in terms of fabrication and maintenance. In addition, these processes are not competent in totally removing various contaminants that exist in dairy effluent. Accordingly, to decrease the energy need, microbial electrochemical technologies (METs) can be effectively employed, thereby also compensating the purification charges by converting the chemical energy present in impurities into bioelectricity and value-added products. Based on this, the current review article illuminates the application of diverse METs as a suitable substitute for traditional technology for treating dairy wastewater. Additionally, several hindrances on the way to real-world application and techno-economic assessment of revolutionary METs are also deliberated.

B. S. Zakaria, B. Dhar

Processes • 2022

: The growing concern about residual antibiotics in the water environment pushes for innovative and cost-effective technologies for antibiotics removal from wastewater. In this context, various microbial electrochemical systems have been investigated as an alternative to conventional wastewater technologies that are usually ineffective for the adequate removal of antibiotics. This review article details the development of stand-alone and hybrid or integrated microbial electrochemical systems for antibiotics removal from wastewater. First, technical features, antibiotics removal efficiencies, process optimization, and technological bottlenecks of these systems are discussed. Sec-ond, a comparative summary based on the existing reports was established to provide insights into the selection between stand-alone and hybrid systems. Finally, research gaps, the relevance of recent progress in complementary areas, and future research needs have been discussed.

S. N. Hosseini, P. S. Das, Vahid Khojasteh Lazarjan et al.

IEEE Transactions on Biomedical Circuits and Systems • 2023

Rapid, high-sensitivity, and real-time characterization of microorganisms plays a significant role in several areas, including clinical diagnosis, human healthcare, early detection of outbreaks, and the protection of living beings. Integrating microbiology and electrical engineering promises the development of low-cost, miniaturized, autonomous, and high-sensitivity sensors to quantify and characterize bacterial strains at various concentrations. Electrochemical-based biosensors are receiving particular attention in microbiological applications among the different biosensing devices. Several approaches have been adopted to design and fabricate cutting-edge, miniaturized, and portable electrochemical biosensors to track and monitor bacterial cultures in real time. These techniques differ in their sensing interface circuits and microelectrode fabrication. The goals of this review are (1) to summarize the current state of CMOS sensing circuit designs in label-free electrochemical biosensors for bacteria monitoring and (2) to discuss the material and size of the electrodes used in electrochemical biosensors in microbiological applications. In this paper, we reviewed the latest and most advanced CMOS integrated interface circuits that have recently been used in electrochemical biosensors to identify and characterize bacteria species, such as impedance spectroscopy, capacitive, amperometry, and voltammetry, etc. In addition to the interface circuit design, other crucial factors, such as the material and scale of the electrodes, must be considered to increase the sensitivity of electrochemical biosensors. Surveying the literature in this field improves our knowledge about the impact of electrode designs and materials on sensing precision and will help future designers adapt, design, and fabricate appropriate electrode configurations based on their application. Thus, we summarized the conventional microelectrode designs and materials mainly employed in microbial sensors, including interdigitated electrodes (IDEs), microelectrode arrays (MEAs), paper, and carbon-based electrodes, etc.

Ruixiang Li, Jinning Wang, Tian Li et al.

Critical Reviews in Environmental Science and Technology • 2022

Abstract Remediation of contaminated soil and sediments has been drawing our attention, efficient and eco-friendly technologies are urgently needed for the removal of pollutants in soil and sediments. Although conventional remediation technologies have been in application for decades and have achieved great performance, the significant drawbacks limit their application (e.g., complicated operation and secondary pollution). Microbial electrochemical system (MES) has been intensively studied as a promising technology for soil/sediment remediation. Compared with other technologies, soil/sediment MES (SMES) exhibited many potential benefits, such as adequate electron acceptors, self-sustained operation, and facile control. However, due to the diversity of soil/sediment contamination and the significant difference in the remediation performance of conventional SMES, it is imperative to develop strategies for enhancing the remediation performance of SMES. In this review, we briefly introduce the removal mechanisms of different pollutants, including the mechanisms of electron releasing, transportation, and receiving. Afterward, we comprehensively present a detailed discussion of the recent progress in the enhancement of soil/sediment remediation in terms of reactor configurations, electrode arrangements, and electrode materials. Moreover, different materials used to amend soil/sediments and their corresponding enhancement principles are summarized in detail. Finally, we discuss the current emerging limitations of SMES and the future research endeavors to improve the performance and promote the practical application. Therefore, this review can fill the gaps in SMES development and guide the practical application in contaminated soil/sediments. Graphical abstract

Kevin Beaver, Ashwini Dantanarayana, Ana Clara Bonizol Zani et al.

Journal of The Electrochemical Society • 2023

With applications in bioremediation, biosensing, and bioenergy, microbial electrochemical systems are a rapidly growing, multidisciplinary field within biological, chemical, and materials science. Since these systems use living microorganisms as biocatalysts, it is important to understand how microbial physiology, specifically biofilm formation, affects these electrochemical systems. Specifically, the literature lacks research that assesses the effects of biofilm on metabolic current output in mediated electron transfer systems. In this study, Rhodobacter capsulatus and Pseudomonas putida GPo1 were used as model, nonpathogenic strains that facilitate electron transfer via diffusible redox mediators. Nitric oxide has gained attention in biomedicine as a gaseous signaling molecule, which at sublethal concentrations may either augment or inhibit biofilm formation depending on the bacterial species. In R. capsulatus, nitric oxide treatment was associated with increased current yield and improved biofilm formation. However, in P. putida-GPo1, nitric oxide treatment corresponded to significantly reduced current output, as well as biofilm dispersal. In addition to highlighting the use of electrochemical tools to assess the effects of nitric oxide in biofilm formation, these findings demonstrate that biofilm-based mediated electron transfer systems benefit from the increased electrochemical output and enhanced cell adhesion, which is promising for more robust applications compared to their planktonic counterpart