Microbial Electrochemical Systems Research Articles

Optimizing Anode Construction for Improved Performance in Ecological Floating Bed Microbial Electrochemical System (ECOFB-MES): Engineering Application and Construction Strategy

Optimizing Anode Construction for Improved Performance in Ecological Floating Bed Microbial Electrochemical System (ECOFB-MES): Engineering Application and Construction Strategy

The promotion of the atrazine degradation mechanism by humic acid in a soil microbial electrochemical system

The enhancing effects of anodes on the degradation of the organochlorine pesticide atrazine (ATR) in soil within microbial electrochemical systems (MES) have been extensively researched. However, the impact and underlying mechanisms of soil microbial electrochemical systems (MES) on ATR degradation, particularly under conditions involving the addition of humic acids (HAs), remain elusive. In this investigation, a soil MES supplemented with humic acids (HAs) was established to assess the promotional effects and mechanisms of HAs on ATR degradation, utilizing EEM-PARAFAC and SEM analyses. Results revealed that the maximum power density of the MES in soil increased by 150%, and the degradation efficiency of ATR improved by over 50% following the addition of HAs. Furthermore, HAs were found to facilitate efficient ATR degradation in the far-anode region by mediating extracellular electron transfer. The components identified as critical in promoting ATR degradation were Like-Protein and Like-Humic acid substances. Analysis of the microbial community structure indicated that the addition of HAs favored the evolution of the soil MES microbial community and the enrichment of electroactive microorganisms. In the ATR degradation process, the swift accumulation of Hydrocarbyl ATR (HYA) was identified as the primary cause for the rapid degradation of ATR in electron-rich conditions. Essentially, HA facilitates the reduction of ATR to HYA through mediated bonded electron transfer, thereby markedly enhancing the efficiency of ATR degradation.

Elucidating the development of cooperative anode-biofilm-structures

Microbial electrochemical systems are a highly versatile platform technology with a particular focus on the interplay of chemical and electrical energy conversion and offer immense potential for a sustainable bioeconomy. The industrial realization of this potential requires a critical focus on biofilm optimization if performance is to be controlled over a long period of time. Moreover, the aspect and influence of cooperativity has to be addressed as many applied anodic bioelectrochemical systems will most likely be operated with a diversity of interacting microbial species. Hence, the aim of this study was to analyze how interspecies dependence and cooperativity of a model community influence the development of anodic biofilms. To investigate biofilm activity in a spatially resolved manner, a microfluidic bioelectrochemical flow cell was developed that can be equipped with user-defined electrode materials and operates under laminar flow conditions. With this infrastructure, the development of single and co-culture biofilms of the two model organisms Shewanella oneidensis and Geobacter sulfurreducens on graphite electrodes was monitored by optical coherence tomography analysis. The interdependence in the co-culture biofilm was achieved by feeding the community with lactate, which is converted by S. oneidensis into acetate, which in turn serves as substrate for G. sulfurreducens. The results show that co-cultivation resulted in the formation of denser biofilms than in single culture. Moreover, we hypothesize that S. oneidensis in return utilizes the conductive biofilm matrix build by G. sulfurreducens for direct interspecies electron transfer (DIET) to the anode. FISH analysis revealed that the biofilms consisted of approximately two-thirds G. sulfurreducens cells, which most likely formed a conductive 3D network throughout the biofilm matrix, in which evenly distributed tubular S. oneidensis colonies were embedded without direct contact to the anode surface. Live/dead staining shows that the outermost biofilm contained almost exclusively dead cells (98 %), layers near the anode contained 45–56 % and the entire biofilm contained 82 % live cells. Our results exemplify how the architecture of the exoelectrogenic biofilm dynamically adapts to the respective process conditions.

Fulvic acid more facilitated the soil electron transfer than humic acid

Humus substances (HSs) participate in extracellular electron transfer (EET), which is unclear in heterogeneous soil. Here, a microbial electrochemical system (MES) was constructed to determine the effect of HSs, including humic acid, humin and fulvic acid, on soil electron transfer. The results showed that fulvic acid led to the optimal electron transfer efficiency in soil, as evidenced by the highest accumulated charges and removal of total petroleum hydrocarbons after 140 days, with increases of 161% and 30%, respectively, compared with those of the control. However, the performance of MES with the addition of humic acid and humin was comparable to that of the control. Fulvic acid amendment enhanced the carboxyl content and oxidative state of dissolved organic matter, endowing a better electron transfer capacity. Additionally, the presence of fulvic acid induced an increase in the abundance of electroactive bacteria and organic degraders, extracellular polymeric substances and functional enzymes such as cytochrome c and NADH synthesis, and the expression of m tr C gene, which is responsible for EET enhancement in soil. Overall, this study reveals the mechanism by which HSs stimulate soil electron transfer at the physicochemical and biological levels and provides basic support for the application of bioelectrochemical technology in soil.

Study on the mechanism of mitigating membrane fouling in MFC-AnMBR coupling system treating sodium and magnesium ion-containing wastewater

ABSTRACT Anaerobic Membrane Bioreactors (AnMBR) offer numerous advantages in wastewater treatment, yet they are prone to membrane fouling after extended operation, impeding their long-term efficiency and stability. In this study, a coupled system was developed using modified conductive membranes as the filtration membrane for the AnMBR and as the anodic conductive membrane in the microbial electrochemical system, with a total volume of approximately 2.57 L. The research focused on understanding the membrane fouling characteristics of the AnMBR when treating wastewater containing sodium ion (Na+) and magnesium ion (Mg2+). When the system was treating wastewater containing Na+, organic pollutants such as proteins and polysaccharides were identified as the primary causes of membrane fouling. Three experimental groups generating different electric currents exhibited extended operational times compared to the open-circuit control group, with extensions of 30, 24, and 15 days, respectively. Conversely, when treating wastewater with Mg2+, organic–inorganic composite fouling, primarily driven by Mg2+ bridging, emerged as the key challenge, with the experimental groups showing operational extensions of 5, 8, and 23 days, respectively, in comparison to the control group. Analysis of proteins and polysaccharides indicated that electric current played a crucial role in reducing organic fouling in the sludge cake layer. When treating wastewater containing Na+, the effectiveness of membrane fouling control was directly proportional to the electric current, while when treating wastewater containing Mg2+, it was directly proportional to the voltage.

Optimum Magnetite–Zeolite Nanoparticles Loading on the Cathode of Microbial Electrochemical–Anaerobic Digestion System for Enhancing Methane Generation

Microbial electrochemical systems (MESs) can enhance methane production in anaerobic digestion, but their performance is hindered by inadequate electron transfer between the cathode and microbes. Magnetite–zeolite (MZ)‐based catalysts accelerate electron exchange; however, the optimal loading of MZ is crucial for maximizing MES performance. In this study, different loadings of the MZ catalyst ranging from 0 to 2 mg cm−2 on the cathode were evaluated to obtain an optimum loading for maximizing methane recovery from MES. Electrochemical analyses demonstrated enhanced electrochemical reduction kinetics of the cathode with increased MZ loading from 0 to 2 mg cm−2. Among the tested loadings, the MES with 1 mg cm−2 MZ on the cathode exhibited the highest methane production rate at 548 mL L−1 d−1, surpassing other MES operations with 2 and 0.5 mg cm−2 (499 and 434 mL L−1 d−1, respectively). Additionally, the MES with 1 mg cm−2 MZ demonstrated the highest soluble chemical oxygen demand removal efficiency of 87% and total coulomb recovery of 1444.06C ± 42.60C, with the lowest amount of volatile fatty acids accumulation. Consequently, MZ is recommended as a superior catalyst for enhancing MES performance and suggested to utilize 1 mg cm−2 MZ loading on the cathode to maximize methane production.

Enrichment of electrogenic microbes on surface-modified stainless steel 304L for rapid start-up of microbial electrochemical sensors

Stainless steel (SS) 304L, a cost-effective and mechanically robust material, is widely used in microbial electrochemical systems as an anode due to its versatility. However, poor biocompatibility and low corrosion resistance limit its potential. This study explores rapid SS surface modification techniques to enhance the sensitivity of microbial electrochemical sensors. Four coatings, namely electroreduction, carbon-coated, flame oxidised, and graphene-coated, were applied to SS electrodes. Surface morphology and characteristics were examined through FESEM-EDX and Raman profiling. The biosensor start-up and microbial enrichment demonstrated an exponential increase in current density, with carbon-based electrodes outperforming iron-based ones. The modified electrodes exhibited enhanced microbial-electrode interactions, evident in altered electrode potential. Starvation and recovery tests revealed distinct patterns, with carbon-coated electrodes showcasing rapid recovery. The air-in-chamber test indicated immediate loss and subsequent recovery of microbial activities upon water circulation. Surface modification significantly influenced the microbial response, with carbon-based coatings demonstrating superior performance. This study provides valuable insights into SS surface modification for improving microbial electrochemical sensor sensitivity, holding promise for diverse applications in environmental monitoring and biosensing.

Joint response mechanism of bioanode and biocathode in single chamber biocathode microbial electrochemical systems started-up with a constant and low resistance

Microbial electrochemical systems (MESs), particularly biocathode MESs, are recognized as environmentally friendly technologies in wastewater treatment. Rapid start-up and achievable high current and power density are desirable for scaled-up MES. The high output current can be obtained under low external resistance, but the response behaviors of bioanode and biocathode during start-up stage under low external resistance need to be clarified. In this study, a 10 L single-chamber biocathode microbial electrochemical system with microbial separator was successfully started within 11 days under a low external resistance of 20 Ω. The maximum power density reached 116.6 mW/m2 on the 9th day. However, the competition between oxygen-reducing bacteria and filamentous bacteria in the biocathode caused the decreased output power and power overshoot. Reducing the external resistance not only eliminated the power overshoot but also enhanced the electroactivity and organic removal efficiency of the bioanode. Additionally, it alleviated the constraint of filamentous bacteria on oxygen mass transfer, thereby enhancing the performance of the biocathode. The comprehensive regulation of the bioanode and the biocathode performance was achieved by reducing external resistance. This study analyzed the joint response mechanism of the bioanode and biocathode, aiming to provide guidance for the application of biocathode microbial electrochemical systems.

Effect of lignocellulosic biomass components on the extracellular electron transfer of biochar-based microbe-electrode in microbial electrochemical systems

Biomass-derived carbon-based electrodes with good biocompatibility, sustainability, and low cost are competitive in microbial electrochemical systems. Unfortunately, biomass composition is complex, and biochar performance is dependent on the kind of biomass, making quantitative function control difficult. Three-dimensional (3D) lignocellulosic carbon-based electrodes were generated in this study by varying the ratios of three natural biopolymers (cellulose, lignin, and hemicellulose). The biopolymer contents significantly impacted the material's physicochemical and electrochemical properties. Only the proper ratio of these natural polymers can ensure the 3D structure's integrity and mechanical strength after carbonization. The greater the cellulose content and the lower the hemicellulose (xylan) content, the lower the ohmic and charge transfer resistance. The maximum power density (Pmax) of the microbial fuel cells equipped with the biopolymer-based anode ranged between 4.5 and 4.8 W m−2, setting a new record for biocarbon electrodes. The highest Pmax was observed when the cellulose, lignin, and xylan ratios were 1:3:2 (4.80 ± 0.04 W m−2). The Pmax correlates with cellulose content more than lignin and xylan and with material capacitance more than with other parameters. High cellulose content facilitates electron transfer but reduces the capacitance of carbon-based electrodes. The material's electron transfer resistance and capacitance contribute to the opposite of the Pmax. So, the interaction with multiple properties influences the electrode performance. This research revealed the effects of natural biopolymer compositions on electrode performance, which was helpful for quantitatively modifying functional carbon-based materials.

Enhanced Succinic Acid Production and Electronic Utilization Efficiency by Actinobacillus succinogenes 130Z in an ORP-Controlled Microbial Electrolysis Cell System

Microbial electrochemical systems have shown great value as a means of enhancing the efficiency of fermentation reactions, but at present, there is no reliable means to balance the extracellular electron supply and corresponding intracellular demands in these systems. The current work describes the unique use of an oxidation–reduction-potential (ORP)-level-controlled microbial electrolysis cell (MEC) system to successfully balance the extracellular electron supply and succinic acid fermentation via A. succinogenes (130Z). The ORP-controlled MEC system with neutral red (NR) yielded a significant increase in succinic acid production (17.21%). The utilization of NR in this MEC system improved the ORP regulatory sensitivity. The optimal approach to the ORP level control was the use of a −400 mV high-voltage electric pulse-based strategy, which increased the yield of succinic acid by 13.08% compared to the control group, and reduced the energy consumption to 52.29% compared to the potentiostatic method. When compared to the −1 V constant potential MEC system, the high-voltage electric pulse-based ORP strategy for the MEC system control provided sufficient electrons to this system while using less electricity (11.96%) and producing 12.48% (74.43 g/L) more succinic acid during fed-batch fermentation. The electronic utilization efficiency of the ORP-controlled MEC system was 192.02%, which was 15.19 times that of the potentiostatic system. The electronic utilization efficiency is significantly increased in the ORP-controlled MEC system. Succinic acid production is ensured by a high-voltage electric pulse-based method, while the influence on cell growth and power consumption are minimized. Fed-batch fermentation with the high-voltage electric pulse-based ORP strategy for MEC system control is noted to be ideal to achieve a further increase in succinic acid concentration and electronic utilization efficiency.

Harnessing fungal bio-electricity: a promising path to a cleaner environment.

Integrating fungi into fuel cell systems presents a promising opportunity to address environmental pollution while simultaneously generating energy. This review explores the innovative concept of constructing wetlands as fuel cells for pollutant degradation, offering a practical and eco-friendly solution to pollution challenges. Fungi possess unique capabilities in producing power, fuel, and electricity through metabolic processes, drawing significant interest for applications in remediation and degradation. Limited data exist on fungi's ability to generate electricity during catalytic reactions involving various enzymes, especially while remediating pollutants. Certain species, such as Trametes versicolor, Ganoderma lucidum, Galactomyces reessii, Aspergillus spp., Kluyveromyce smarxianus, and Hansenula anomala, have been reported to generate electricity at 1200 mW/m3, 207 mW/m2, 1,163 mW/m3, 438 mW/m3, 850,000 mW/m3, and 2,900 mW/m3, respectively. Despite the eco-friendly potential compared to conventional methods, fungi's role remains largely unexplored. This review delves into fungi's exceptional potential as fuel cell catalysts, serving as anodic or cathodic agents to mitigate land, air, and water pollutants while simultaneously producing fuel and power. Applications cover a wide range of tasks, and the innovative concept of wetlands designed as fuel cells for pollutant degradation is discussed. Cost-effectiveness may vary depending on specific contexts and applications. Fungal fuel cells (FFCs) offer a versatile and innovative solution to global challenges, addressing the increasing demand for alternative bioenergy production amid population growth and expanding industrial activities. The mechanistic approach of fungal enzymes via microbial combinations and electrochemical fungal systems facilitates the oxidation of organic substrates, oxygen reduction, and ion exchange membrane orchestration of essential reactions. Fungal laccase plays a crucial role in pollutant removal and monitoring environmental contaminants. Fungal consortiums show remarkable potential in fine-tuning FFC performance, impacting both power generation and pollutant degradation. Beyond energy generation, fungal cells effectively remove pollutants. Overall, FFCs present a promising avenue to address energy needs and mitigate pollutants simultaneously.

Recent advances in the electrochemical production of hydrogen peroxide

Hydrogen peroxide (H2O2) is an innovative and environmentally friendly oxidant that finds wide-ranging applications across multiple industries. In the past, H2O2 production predominantly relied on the anthraquinone method, which had drawbacks such as the generation of organic waste and the requirement for energy-intensive reactions. A cheap, efficient, and sustainable way of producing H2O2 may be achieved through the redox reaction between oxygen and water. On both small and large scales, the electrosynthesis of H2O2 is practical and affordable. In recent years, it has been thought that the energy-intensive anthraquinone process may be replaced by the electrochemical synthesis of H2O2 via the two-electron oxygen reduction reaction (ORR) route. To eliminate the organic pollutants found in drinking water and industrial effluent, highly effective hydrogen peroxide (H2O2) must be produced electrochemically using gas diffusion electrodes (GDEs). Compared to other carbonaceous cathodes, the GDEs as cathodic electrocatalysts demonstrate greater cost-effectiveness, lower energy consumption, and higher oxygen utilization efficiency for the formation of H2O2. A promising alternative for enabling the growth of sustainable economics in the W&W sector is microbial electrochemical systems (MESs) that create H2O2. To enhance the efficiency and predictability of H2O2 production in MESs, a machine-learning approach was adopted, incorporating a meta-learning methodology to forecast the generation rate of H2O2 in MES based on the seven input variables, comprising several design and operational parameters.

Insights into sulfur cycling contribution to nitrogen removal in sulfur autotrophic denitrification combined microbial electrochemical denitrification

In the face of increasing discharge standards, sulfur autotrophic denitrification (SAD) is gradually applied for deep nitrogen removal of electron-donor-deficient waters. However, the product sulfate induces secondary pollution in the effluent, and the proton consumption from alkalinity is detrimental to the stable operation of the system. In this study, a sulfur autotrophic denitrification coupled with microbial electrochemical denitrification system (S-MED) is proposed to reduce the addition of inorganic sulfur, alleviating nitrite accumulation, while enabling the system to self-sustain at a neutral pH. The S-MED system that was operated under the applied potential of −0.5 V achieved a nitrate removal of 97.5 ± 1.57 % and a total nitrogen removal of 90.3 ± 4.27 %, which were 14.6 % and 68.0 % higher than the SAD systems in control under the S/N molar ratio of 0.8. The nitrite accumulation rate was reduced by 69.1 % compared to SAD. The effluent sulfate concentration was also reduced to 5.8 mg/mg-N TN removal. The electrochemically active denitrifying bacterium Thiobacillus was enriched in the coupled system, and the copy numbers of functional genes of narGHI, napAB, and nirK involved in denitrification were increased. According to the microbial analysis and electrochemical characteristics, it suggested that S2- might be generated from sulfate with the presence of electrodes, enabling the cycling of sulfur, providing mobile electron carriers for denitrification, thus allowing bacteria to conduct denitrification by indirectly obtaining electrons from the electrode.

Effects of long-term and incremental exposure to toxic pollutants on the current generation and microbial communities of electrochemically active bacteria

The study first reveals the long-term effects of toxic exposure on the current generation and the microbial communities of EAB. Acute toxicity inhibits the current generation in the early stage but gradually diminish during the middle and end stages.

Nitric Oxide As a Signaling Molecule for Biofilm Formation and Dispersal in Mediated Electron Transfer Microbial Electrochemical Systems

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, namely 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 counterparts. Figure 1

Microbial electrochemical systems for bioelectricity generation: Current state and future directions

Increasing environmental pollution is a major concern, driven by fossil fuel consumption and growing energy demands. Energy production from various waste materials such as wastewater and sludge, could be proposed as a practical and appropriate solution to the energy crisis and waste disposal simultaneously. This approach not only addresses waste management but also generates different forms of bioenergy through biological treatment processes.Bioelectricity, a renewable and cost-effective energy source, is generated by electric potentials and currents that are produced or exist inside living microorganisms. In fact, bioelectricity is obtained from bioelectric potentials in various biological processes and through the conversion of chemical energy into electrical energy. Recently, the application of microbial electrochemical systems (MESs) has gained significant importance as a promising means of bioelectricity production. Various MESs leading to bioelectricity generation include microbial fuel cells (MFCs) and microbial desalination cells (MDCs).This paper explores the definitions of MESs, their detailed mechanisms, configurations, operational parameters, benefits and limitations, as well as the kinetics and thermodynamics associated with bioelectricity generation technologies. Additionally, it investigated the use of various types of artificial intelligence algorithms for modeling and optimizing biological processes for bioelectricity generation.

Spray coating of carbon nanoparticles as an effective and scalable method to enhance the performance of stainless steel anode in microbial electrochemical systems

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A wood pulp sponge cleaning wipe as a high-performance bioanode material in microbial electrochemical systems for its vast biomass carrying capacity, large capacitance, and small charge transfer resistance

Microbial electrochemical systems are a promising green and sustainable technology that can transform waste into electricity. Improving conversion efficiency and lowering system costs, particularly for electrodes, are the primary directions that promote practical application. Cellulose sponges made from wood pulp have been industrially mass-produced in various application scenarios due to their porosity and green sustainability. In this study, the three-dimensional (3D) porous cellulose sponges carbon (CSC) was obtained by directly carbonizing cellulose sponges at different temperatures (600, 700, 800, 900, 1000, and 1100 °C). It has been successfully used as a high-performance anode in microbial fuel cells (MFCs). The carbonization temperature significantly impacted the materials’ specific surface area, conductivity, and capacitance. The greater the anode material's carbonization temperature, the lower the charge transfer resistance and the higher the maximum power density (CSC-1100, 4.1 ± 0.1 W m–2). The CSC-700′s maximum power density (3.62 ± 0.11 W m–2) was the highest power density reported to date among lignocellulose-based anodes with relatively low energy consumption. The pleated multilayer porous surface promotes microbial adhesion and can build thicker biofilms with the highest biomass of 2661 ± 117 μg cm–2 (CSC-1100) and containing 86 % electrogenic bacteria (Geobacter). To investigate the effect of conducting polymers on the material's surface, we introduced polyaniline and polypyrrole. We found that the CSC-1000/PPy bioanodes produced a maximum power density (4.18 ± 0.05 W m–2), slightly higher than of without polypyrrole-modified (CSC-1000, 3.99 ± 0.06 W m–2), indicating that the CSCs anode surface had excellent electron transfer efficiency and could achieve the same amount of energy as the polypyrrole surface. This study introduced a promising method for fabricating high-performance anodes using low-cost, industrialized, and sustainable materials.

Autoinducer-2 quorum sensing regulates biofilm formation and chain elongation metabolic pathways to enhance caproate synthesis in microbial electrochemical system

Quorum sensing (QS) have been explored extensively. However, most studies focused on N-acyl homoserine lactones (AHLs) participating in intraspecies QS. In this study, autoinducer-2 (AI-2, participating in interspecies QS) with different concentration was investigated for chain elongation in microbial electrosynthesis (MES). The results demonstrated that the R3 treatment, which involved adding 10 μM of 4,5-dihydroxy-2,3-pentanedione (DPD) in the reactor, exhibited the best performance. The concentration of caproate was increased by 66.88% and the redox activity of cathodic electroactive biofilms (EABs) was enhanced. Meanwhile, microbial community data indicated that Negativicutes relative abundance was increased obviously in R3 treatment. In this study, the transcriptome Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases were used to analyze the metabolic pathway of chain elongation involving fatty acid biosynthesis (FAB) pathway and reverse β-oxidization (RBO) pathway. KEGG analysis revealed that fatty acid elongation metabolism (p < 0.001), tryptophan metabolism (p < 0.01), arginine and proline metabolism (p < 0.05) were significantly improved in R3 treatment. GO analysis suggested that R3 treatment mainly upregulated significantly transmembrane signaling receptor activity (p < 0.01), oxidoreductase activity (p < 0.05), and phosphorelay signal transduction (p < 0.05). Moreover, metatranscriptomic analyses also showed that R3 treatment could upregulate the LuxP extracellular receptor, LuxO transcriptional activator, LsrB periplasmic protein, and were beneficial to both FAB and RBO pathways. These findings provided a new insight into chain elongation in MES system.

Pyrolyzed sediment accelerates electron transfer and regulates rhodamine B biodegradation

Electron transfer efficiency is a key factor that determined the removal of environmental pollution through biodegradation. Electron shuttles exogenously addition is one of the measures to improve the electron transfer efficiency. In this study, the sediment was pyrolyzed at different temperature to investigate its properties of mediating electron transfer and removing of rhodamine B (RhB) in microbial electrochemical systems (MESs). Sediments pyrolyzed at 300 °C (PS300) and 600 °C (PS600) have promoted electron transfer which led to 16 % enhancement of power generation while the result is reversed at 900 °C (PS900). Although power output of PS300 and PS600 are similar, the removal efficiency of RhB is not consistent, which may be caused by the biofilm structure difference. Microbial community analysis revealed that the abundance of EAB and toxicity-degrading bacteria (TDB) in PS600 was 6 % higher than that in PS300. The differentiation of microbial community also affected the metabolic pathway, the amino synthesis and tricarboxylic acid cycle were primarily upregulated with PS600 addition, which enhanced the intracellular metabolism. However, a more active cellular anabolism occurred with PS300, which may have been triggered by RhB toxicity. This study showed that pyrolytic sediment exhibits an excellent ability to mediate electron transport and promote pollutant removal at 600 °C, which provides a techno-economically feasible scenario for the utilization of low-carbon-containing solid wastes.