Jinsong Du, Jiyu Xin, Menghua Liu et al.

Frontiers in Microbiology • 2022

Roseiflexus castenholzii is an ancient green non-sulfur bacteria that absorbs the solar energy through bacteriochlorophylls (BChls) bound in the only light harvesting (LH) complex, and transfers to the reaction center (RC), wherein primary charge separation occurs and transforms the energy into electrochemical potentials. In contrast to purple bacteria, R. castenholzii RC-LH (rcRC-LH) does not contain an H subunit. Instead, a tightly bound tetraheme cytochrome c subunit is exposed on the P-side of the RC, which contains three BChls, three bacteriopheophytins (BPheos), two menaquinones, and one iron for electron transfer. These novel structural features of the rcRC-LH are advantageous for enhancing the electron transfer efficiency and subsequent photo-oxidation of the c-type hemes. However, the photochemical properties of rcRC-LH and its applications in developing the photo-bioelectrochemical cells (PBECs) have not been characterized. Here, we prepared a PBEC using overlapped fluorine-doped tin oxide (FTO) glass and Pt-coated glass as electrodes, and rcRC-LH mixed with varying mediators as the electrolyte. Absence of the H subunit allows rcRC-LH to be selectively adhered onto the hydrophilic surface of the front electrode with its Q-side. Upon illumination, the photogenerated electrons directly enter the front electrode and transfer to the counter electrode, wherein the accepted electrons pass through the exposed c-type hemes to reduce the excited P+, generating a steady-state current of up to 320 nA/cm2 when using 1-Methoxy-5-methylphenazinium methyl sulfate (PMS) as mediator. This study demonstrated the novel photoelectric properties of rcRC-LH and its advantages in preparing effective PBECs, showcasing a potential of this complex in developing new type PBECs.

K. Cheng, A. Kaksonen, R. Cord-Ruwisch

Environmental Technology • 2022

Bioelectrochemical systems (BES) are emerging environmental biotechnology for recovering ammonia from waste streams. It has been tested extensively for treating ammonium-rich wastewater. This study examined the suitability of BES to facilitate carbon removal and ammonium extraction from a low ammonium liquor (3.7 mM) that mimics municipal wastewater, and concomitant production of high-purity hydrogen gas, which could potentially be harnessed as a fuel or internally recycled for ammonia stripping. Results showed that a two-chamber cation exchange membrane-equipped BES enabled a high hydrogen yield (22.8 m3 H2 m-3 d-1; >98% cathodic efficiency) and chemical oxygen demand (COD) removal (80%; 2.43 kg COD m-3d-1 at a hydraulic retention time of 4.4 h). However, for the treatment of wastewater the system demanded high energy (2.3 kWh kg COD-1; 152 kWh kg-1 N removed) and base for pH adjustment. The technology may be more suitable for recovering ammonium from wastewaters with molar ammonium to BOD ratio closer to the desired stoichiometric ratio of four, and for waste streams containing sufficient alkalinity or pH-buffering capacity, eliminating the need for dosing cation-bearing alkali.

Cong-Long Nguyen, B. Tartakovsky, L. Woodward

ACS Omega • 2019

Direct electricity production from waste biomass in a microbial fuel cell (MFC) offers the advantage of producing renewable electricity at a high Coulombic efficiency. However, low MFC voltage (below 0.5 V) necessitates the simultaneous operation of multiple MFCs controlled by a power management system (PMS) adapted for operating bioelectrochemical systems with complex nonlinear dynamics. This work describes a novel PMS designed for efficient energy harvesting from multiple MFCs. The PMS includes a switched-capacitor-based converter, which ensures operation of each MFC at its maximum power point (MPP) by regulating the output voltage around half of its open-circuit voltage. The open-circuit voltage of each MFC is estimated online regardless of MFC internal parameter knowledge. The switched-capacitor-based converter is followed by an upconverter, which increases the output voltage to a required level. Advantages of the proposed PMS include online MPP tracking for each MFC and high (up to 85%) power conversion efficiency. Also, the PMS prevents voltage reversal by disconnecting an MFC from the circuit whenever its voltage drops below a predefined threshold. The effectiveness of the proposed PMS is verified through simulations and experimental runs.

María Teresa Pines Pozo, Ester Lopez Fernandez, José Villaseñor et al.

Applied Sciences • 2025

The rapid technological advancements and the shift towards clean energy have significantly increased the demand for metals, leading to an increasing metal pollution problem. This review explores recent advances in bioelectrochemical systems (BES) for metal recovery from waste, especially Acid Mine Drainage (AMD) and Electrical, Electronic Wastes (EEW) and waste from smelters, highlighting their potential as a sustainable and economically viable alternative to traditional methods. This study addresses the applications and limitations of current BES recovery techniques. BES, including microbial fuel cells (MFCs), microbial electrolytic cells (MECs), and Microbial Desalination Cells (MDCs), offer promising solutions by combining microbial processes with electrochemical reactions to recover valuable metals while reducing energy requirements. This review categorizes recent research into two main areas: pure BES applications and BES coupled with other technologies. Key findings include the efficiency of BES in recovering metals like copper, chromium, vanadium, iron, zinc, nickel, lead, silver, and gold and the potential for integrating BES with other systems to enhance performance. Despite significant progress in BES application for metal recovery, challenges such as high costs and slow kinetics remain, necessitating further research to optimize materials, configurations, and operational conditions. The work also includes an economic assessment and guidelines for BES development and upscale. This review underscores the critical role of BES in advancing sustainable metal recovery and mitigating the environmental impact of metal pollution.

Nishat Khan, M. Danish Khan, A. Nizami et al.

RSC Advances • 2018

Bio-electrochemical degradation of pentachlorophenol was carried out in single as well as dual chambered microbial fuel cell (MFC) with simultaneous production of electricity. The maximum cell potential was recorded to be 787 and 1021 mV in single and dual chambered systems respectively. The results presented nearly 66 and 89% COD removal in single and dual chambered systems with corresponding power densities of 872.7 and 1468.85 mW m−2 respectively. The highest coulombic efficiency for single and dual chambered counterparts was found to be 33.9% and 58.55%. GC-MS data revealed that pentachlorophenol was more effectively degraded under aerobic conditions in dual-chambered MFC. Real-time polymerase chain reaction showed the dominance of exoelectrogenic Geobacter in the two reactor systems with a slightly higher concentration in the dual-chambered system. The findings of this work suggested that the aerobic treatment of pentachlorophenol in cathodic compartment of dual chambered MFC is better than its anaerobic treatment in single chambered MFC in terms of chemical oxygen demand (COD) removal and output power density.

E. Labelle, H. May

Frontiers in Microbiology • 2017

It was hypothesized that a lack of acetogenic biomass (biocatalyst) at the cathode of a microbial electrosynthesis system, due to electron and nutrient limitations, has prevented further improvement in acetate productivity and efficiency. In order to increase the biomass at the cathode and thereby performance, a bioelectrochemical system with this acetogenic community was operated under galvanostatic control and continuous media flow through a reticulated vitreous carbon (RVC) foam cathode. The combination of galvanostatic control and the high surface area cathode reduced the electron limitation and the continuous flow overcame the nutrient limitation while avoiding the accumulation of products and potential inhibitors. These conditions were set with the intention of operating the biocathode through the production of H2. Biofilm growth occurred on and within the unmodified RVC foam regardless of vigorous H2 generation on the cathode surface. A maximum volumetric rate or space time yield for acetate production of 0.78 g/Lcatholyte/h was achieved with 8 A/Lcatholyte (83.3 A/m2projected surface area of cathode) supplied to the continuous flow/culture bioelectrochemical reactors. The total Coulombic efficiency in H2 and acetate ranged from approximately 80–100%, with a maximum of 35% in acetate. The overall energy efficiency ranged from approximately 35–42% with a maximum to acetate of 12%.

Lianbin Cao, Hongmei Sun, Yamei Ma et al.

Microbial Cell Factories • 2023

The strain Lsc-8 can produce a current density of 33.08 µA cm^−2 using carboxymethylcellulose (CMC) as a carbon source in a three-electrode configuration. A co-culture system of strain Lsc-8 and Geobacter sulfurreducens PCA was used to efficiently convert cellulose into electricity to improve the electricity generation capability of microbial fuel cells (MFCs). The maximum current density achieved by the co-culture with CMC was 559 μA cm^−2, which was much higher than that of strain Lsc-8 using CMC as the carbon source. The maximum power density reached 492.05 ± 52.63 mW cm^−2, which is much higher than that previously reported. Interaction mechanism studies showed that strain Lsc-8 had the ability to secrete riboflavin and convert cellulose into acetic acid, which might be the reason for the high electrical production performance of the co-culture system. In addition, to the best of our knowledge, a co-culture or single bacteria system using agricultural straw as the carbon source to generate electricity has not been reported. In this study, the maximum current density of the three-electrode system inoculated with strain Lsc-8 was 14.56 μA cm^−2 with raw corn stover as the sole carbon source. Raw corn stover as a carbon source was also investigated for use in a co-culture system. The maximum current density achieved by the co-culture was 592 μA cm^−2. The co-culture system showed a similar electricity generation capability when using raw corn stover and when using CMC. This research shows for the first time that a co-culture or single bacteria system can realize both waste biomass treatment and waste power generation.

Jung-Chen Wu, Wei‐Mon Yan, Chin‐Tsan Wang et al.

Energies • 2018

Due to the fact that Iron oxide (Fe2O3) is known to have a good effect on the photochemical reaction of catalysts, an investigation in this study into the enhancement of the degradation performance of bio-electro-Fenton microbial fuel cells (Bio-E-Fenton MFCs) was carried out using three photocatalytic cathodes. These cathodes were produced at different calcination temperatures of Fe2O3 ranging from 500 °C to 900 °C for realizing their performance as photo catalysts within the cathodic chamber of an MFC, and they were compared for their ability to degrade oily wastewater. Results show that a suitable temperature for the calcination of iron oxide would have a significantly positive effect on the performance of Bio-E-Fenton MFCs. An optimal calcination temperature of 500 °C for Fe2O3 in the electrode material of the cathode was observed to produce a maximum power density of 52.5 mW/m2 and a chemical oxygen demand (COD) degradation rate of oily wastewater (catholyte) of 99.3% within one hour of operation. These novel findings will be useful for the improvement of the performance and applications of Bio-E-Fenton MFCs and their future applications in the field of wastewater treatment.

G. M. Aleid, Anoud Saud Alshammari, Asma D. Alomari et al.

Processes • 2023

One of the most advanced systems of microbial fuel cells is the benthic microbial fuel cell (BMFC). Despite several developments, this strategy still has a number of significant flaws, such as instable organic substrate. Waste material (sugarcane) is used as a substrate in this work to address the organic substrate instability. The process was operated continuously for 70 days. A level of 300 mV was achieved after 33 days of operation, while the degradation efficiencies of Pb (II), Cd (II), and Cr (III) were more than 90%. More than 90% of the removed chemical oxygen demand (COD) was also recorded. The measured power density was 3.571 mW/m2 at 1000 external resistance with 458 internal resistance. This demonstrates that electrons are effectively transported throughout the operation. The Bacillus strains are the most dominant bacterial community on the surface of the anode. This research’s mechanism, which involves metal ion degradation, is also explained. Finally, parameter optimization indicated that pH 7 works efficiently. In addition to that, there are some future perspectives and concluding remarks enclosed.

Hailiang Song, Shuai Zhang, Xizi Long et al.

Water • 2017

Constructed wetland-coupled microbial fuel cell systems (CW-MFCs) incorporate an aerobic zone and an anaerobic zone to generate electricity that achieves the oxidative degradation of contaminants. However, there are few reports on the performance of such coupled systems. In this study, we determined the optimal configuration of CW-MFCs to characterize their electricity generation performance. Based on the results using different levels of dissolved oxygen among the CW-MFCs, we concluded that a 20-cm distance between the anode and cathode produced an optimal removal of chemical oxygen demand (COD) of 94.90% with a 0.15 W/m3 power density, 339.80 Ω internal resistance, and 0.31% coulombic efficiency. In addition, a COD of 200 mg/L provided greater electricity generation (741 mV open circuit voltage, 0.20 W/m3 power density, 339.80 Ω internal resistance, and 0.49 mA current) and purification ability (90.45% COD removal) to meet system COD loading limitations than did higher COD values. By adding 50 mM phosphate buffer solution to synthetic wastewater, relatively high conductivity and buffer capacity were achieved, resulting in improvement in electricity generation. These findings highlight important aspects of bioelectricity generation in CW-MFCs.

Chia-Chieh Hsu, Yi-Chu Lin, Yaobao Lin et al.

Advanced Energy and Sustainability Research • 2021

Microbial fuel cells (MFCs), which convert chemical energy into electricity using microbes, are an emerging sustainable energy technology. However, high costs and low power output limit the advanced development of MFCs. This study utilizes the agricultural waste, Trapa natans husks, to obtain low‐cost nanoporous carbons. The Trapa natans husk‐derived nanoporous carbons (TNHs) are used as electrode materials in Escherichia coli system‐based MFCs. After optimization of both anode and cathode materials for MFCs, a high average power density of 5713 mW m−2 is achieved, which is 1.9 times greater than that of commercial activated carbon. It is shown that TNHs have better bacterial adhesion and electrochemical activities owing to their favorable pore size distribution, suitable functional group, high surface area, and excellent biocompatibility and conductivity. Furthermore, the supercapacitors (SCs) with TNH‐based electrodes are utilized to store the energy generated from MFCs. The SC with TNH‐600 electrodes exhibits a high specific capacitance of 84 F g−1 at a current density of 1 A g−1 after 1000 cycles. This study demonstrates that TNH is a promising electrode material for biofriendly and renewable MFCs, and the MFC‐SC system with TNH electrodes is a high‐power sustainable energy generation and storage device.

Yanhua Wang, Jiayan Wu, Shengke Yang et al.

International Journal of Environmental Research and Public Health • 2018

Due to the known problems of microbial fuel cells (MFCs), such as low electricity generation performance and high cost of operation, we modified the electrode with graphene and polyaniline (PANI) is a single-chamber air-cathode MFC and then evaluated the effects of electrode modification on MFC electricity generation performance. Carbon cloth electrodes (unmodified, CC; graphene-modified, G/CC; and polyaniline-graphene-modified, PANI-G/CC) were prepared using the impregnation method. Sulfonated cobalt phthalocyanine (CoPcS) was then introduced as a cathode catalyst. The Co-PANI-G/CC cathode showed higher catalytic activity toward oxygen reduction compared with other electrodes. The maximum power density of the MFC with Co-PANI-G/CC cathode was 32.2 mW/m2, which was 1.8 and 6.1 times higher than the value obtained with Co-G/CC and Co/CC cathodes, respectively. This indicates a significant improvement in the electricity generation of single-chamber MFCs and provides a simple, effective cathode modification method. Furthermore, we constructed single-chamber MFCs using the modified anode and cathode and analyzed electricity generation and oxytetracycline (OTC) degradation with different concentrations of OTC as the fuel. With increasing added OTC concentration, the MFC performance in both electricity generation and OTC degradation gradually decreased. However, when less than 50 mg/L OTC was added, the 5-day degradation rate of OTC reached more than 90%. It is thus feasible to process OTC-containing wastewater and produce electricity using single-chamber MFCs, which provides a new concept for wastewater treatment.

Lu Wang, Dayong Xu, Qingyun Zhang et al.

Environmental Science and Pollution Research • 2021

A microbial fuel cell coupled with constructed wetland (CW-MFC) was built to remove heavy metals (Zn and Ni) from sludge. The performance for the effects of substrates (granular activated carbon (GAC), ceramsite) and plants ( Iris pseudacorus , water hyacinth ) towards the heavy metal treatment as well as electricity generation was systematically investigated to determine the optimal constructions of CW-MFCs. The CW-MFC systems possessed higher Zn and Ni removal efficiencies as compared to CW. The maximal removal rates of Zn (76.88%) and Ni (66.02%) were obtained in system CW-MFC based on GAC and water hyacinth (GAC- and WH-CW-MFC). Correspondingly, the system produced the maximum voltage of 534.30 mV and power density of 70.86 mW·m −3 , respectively. Plant roots and electrodes contributed supremely to the removal of heavy metals, especially for GAC- and WH-CW-MFC systems. The coincident enrichment rates of Zn and Ni reached 21.10% and 26.04% for plant roots and 14.48% and 16.50% for electrodes, respectively. A majority of the heavy metals on the sludge surface were confirmed as Zn and Ni. Furthermore, the high-valence Zn and Ni were effectively reduced to low-valence or elemental metals. This study provides a theoretical guidance for the optimal construction of CW-MFC and the resource utilization of sludge containing heavy metals.

M. Abdelkareem, S. Alshathri, M. S. Masdar et al.

Water • 2023

Due to their toxicity, Cr(VI) levels are subject to strict legislation and regulations in various industries and environmental contexts. Effective treatment technologies are also being developed to decrease the negative impacts on human health and the environment by removing Cr(VI) from water sources and wastewater. As a result, it would be interesting to model and optimize the Cr(VI) removal processes, especially those under neutral pH circumstances. Microbial fuel cells (MFCs) have the capacity to remove Cr(VI), but additional research is needed to enhance their usability, increase their efficacy, and address issues like scalability and maintaining stable operation. In this research work, ANFIS modeling and artificial ecosystem optimization (AEO) were used to maximize Cr(VI) removal efficiency and the power density of MFC. First, based on measured data, an ANFIS model is developed to simulate the MFC performance in terms of the Cu(II)/Cr(VI) ratio, substrate (sodium acetate) concentration (g/L), and external resistance Ω. Then, using artificial ecosystem optimization (AEO), the optimal values of these operating parameters, i.e., Cu(II)/Cr(VI) ratio, substrate concentration, and external resistance, are identified, corresponding to maximum Cr(VI) removal efficiency and power density. In the ANFIS modeling stage of power density, the coefficient-of-determination is enhanced to 0.9981 compared with 0.992 (by ANOVA), and the RMSE is decreased to 0.4863 compared with 16.486 (by ANOVA). This shows that the modeling phase was effective. In sum, the integration between ANFIS and AEO increased the power density and Cr(VI) removal efficiency by 19.14% and 15.14%, respectively, compared to the measured data.

Elif DURNA PİŞKİN, N. Genç

Environmental Technology • 2023

ABSTRACT Microbial fuel cell technology draws attention with its ability to directly recover electrical energy from various organic materials. In this study, the operating conditions affecting the oxidation–reduction and electricity generation efficiency of MFC were optimized using the Taguchi Experimental Design model. Optimization was carried out for maximum power density, coulombic efficiency, azo dye removal, and COD removal. With the determined optimum conditions (cathode pH of 3.0, cathode oxygen status of anaerobic, anode substrate of pre-treated, external resistance of 100 Ω, cathode electrode type of plain carbon, cathode electrode surface of 22 cm2, cathode conductivity of 20 µs/cm), 177.03 mW/m2 power density, 7.50% coulombic efficiency, 91.26% azo dye removal efficiency and 21.61% COD removal efficiency were obtained. By Pareto analysis, it was determined that the power density, coulombic efficiency and COD removal efficiency were most affected by the substrate type at the anode, and the azo dye removal was most affected by the catholyte pH. The maximum power density and internal resistance of the MFC operated under optimum conditions were determined as 145.11 mW/m2 and 243.30 Ω, respectively by the polarization curve. Cyclic voltammetry was also performed for the electrochemical characterization of MFC operated under optimum conditions. An anodic peak at −183.2 mV and a cathodic peak at −181.2 mV was visible in the CV curve. GRAPHICAL ABSTRACT

Mary-Rafunzel P. Bandoquillo, Hanna Patricia M. Labrador, K. Pamintuan et al.

2024 2nd International Conference on Power and Renewable Energy Engineering (PREE) • 2024

Plant microbial fuel cell (PMFC) is a bioelectrochemical system developed to generate energy from plant bacteria through photosynthesis without disrupting the soil and plants. In this study, a new design of the PMFC model was introduced using 3D printing technology. Its electricity generation potential was observed using C. comosum as a sample plant for the PMFC set-up. Nine different systems of PMFC stake design with varying numbers and lengths of cathode were examined to determine the optimum surface area ratio of the cathode to the anode and its effect on the power generation of the PMFC design. System 7, with the highest cathode-to-anode surface area ratio, generates the highest power and power density of 0.2879 μW and 22.79 μW/ m2, respectively. It was found that a ratio of approximately 2.829:1 gives the highest average daily power density. Overall, the result of this study shows that the surface area ratio has been found to affect the performance of the PMFC stake design greatly and, with accurate design and material, can serve as an alternative renewable energy source.

A. Netsch, Shaswata Sen, Harald Horn et al.

Biosensors • 2025

Industrially applied bioelectrochemical systems require long-term stable operation, and hence the control of biofilm accumulation on the electrodes. An optimized application of biofilm control mechanisms presupposes on-line, in-situ monitoring of the accumulated biofilm. Heat transfer sensors have successfully been integrated into industrial systems for on-line, non-invasive monitoring of biofilms. In this study, a mathematical model for the description of the sensitivity of a heat transfer biofilm sensor was developed, incorporating the hydrodynamic conditions of the fluid and the geometrical properties of the substratum. This model was experimentally validated at different flow velocities by integrating biofilm sensors into cylindrical pipes and planar mesofluidic flow cells with a carbonaceous substratum. Dimensionless sensor readings were correlated with the mean biovolume measured gravimetrically, and optical coherence tomography was used to determine the sensors’ sensitivity. The biofilm sensors applied in the planar flow cells revealed an increase in sensitivity by a factor of 6 compared to standard stainless steel pipes, as well as improved sensitivity at higher flow velocities.

P. Gotovtsev

Applied Sciences • 2020

There are a number of significant changes taking place in modern city development and most of them are based on the number of recent technological progress. This paper provides a review and analysis of recent approaches of biotechnology that can find a place in today’s cities and discusses how those technologies can be integrated into a city’s Internet of Things (IoT). Firstly, several biotechnologies that focus on rain gardens, urban vertical farming systems, and city photobioreactors are discussed in the context of their integration in a city’s IoT. The next possible application of biofuel cells to the sensor network’s energy supply is discussed. It is shown that such devices can influence the low-power sensor network structure as an additional energy source for transmitters. This paper shows the possibility of bioelectrochemical biosensor applications, discusses self-powered biosensors, and shows that such a system can be widely applied to rainwater monitoring in rain gardens and green streets. Significant attention is paid to recent approaches in synthetic biology. Both cell-based biosensors and bioactuators with synthetic genetic circuits are discussed. The development of cell-based biosensors can significantly enhance the sensing possibilities of a city’s IoT. We show the possible ways to develop cyber-physical systems (CPSs) with the systems mentioned above. Aspects of data handling for the discussed biotechnologies and the methods of intelligent systems, including those that are machine learning-based, applied to the IoT in a city are presented.

Rong Cai, Chiagoziem Ngwadom, Ravindra Saxena et al.

Nature Communications • 2024

Point-of-care sensors, which are low-cost and user-friendly, play a crucial role in precision medicine by providing quick results for individuals. Here, we transform the conventional glucometer into a 4-hydroxytamoxifen therapeutic biosensor in which 4-hydroxytamoxifen modulates the electrical signal generated by glucose oxidation. To encode the 4-hydroxytamoxifen signal within glucose oxidation, we introduce the ligand-binding domain of estrogen receptor-alpha into pyrroloquinoline quinone-dependent glucose dehydrogenase by constructing and screening a comprehensive protein insertion library. In addition to obtaining 4-hydroxytamoxifen regulatable engineered proteins, these results unveil the significance of both secondary and quaternary protein structures in propagation of conformational signals. By constructing an effective bioelectrochemical interface, we detect 4-hydroxytamoxifen in human blood samples as changes in the electrical signal and use this to develop an electrochemical algorithm to decode the 4-hydroxytamoxifen signal from glucose. To meet the miniaturization and signal amplification requirements for point-of-care use, we harness power from glucose oxidation to create a self-powered sensor. We also amplify the 4-hydroxytamoxifen signal using an organic electrochemical transistor, resulting in milliampere-level signals. Our work demonstrates a broad interdisciplinary approach to create a biosensor that capitalizes on recent innovations in protein engineering, electrochemical sensing, and electrical engineering.

Jiwon Woo, E. Y. Lee, Hyo-Suk Park et al.

Journal of Visualized Experiments • 2018

Since the development of CLARITY, a bioelectrochemical clearing technique that allows for three-dimensional phenotype mapping within transparent tissues, a multitude of novel clearing methodologies including CUBIC (clear, unobstructed brain imaging cocktails and computational analysis), SWITCH (system-wide control of interaction time and kinetics of chemicals), MAP (magnified analysis of the proteome), and PACT (passive clarity technique), have been established to further expand the existing toolkit for the microscopic analysis of biological tissues. The present study aims to improve upon and optimize the original PACT procedure for an array of intact rodent tissues, including the whole central nervous system (CNS), kidneys, spleen, and whole mouse embryos. Termed psPACT (process-separate PACT) and mPACT (modified PACT), these novel techniques provide highly efficacious means of mapping cell circuitry and visualizing subcellular structures in intact normal and pathological tissues. In the following protocol, we provide a detailed, step-by-step outline on how to achieve maximal tissue clearance with minimal invasion of their structural integrity via psPACT and mPACT.

Guiping Ren, Yuan Sun, Manyi Sun et al.

Minerals • 2017

Exploring the interplay between sunlight, semiconducting minerals, and microorganisms in nature has attracted great attention in recent years. Here we report for the first time the investigation of the interaction between a hematite photoelectrode and Pseudomonas aeruginosa PAO1 under visible light irradiation. Hematite is the most abundant mineral on earth, with a band gap of 2.0 eV. A hematite electrode was electrochemically deposited on fluorine-doped tin oxide (FTO). It was thoroughly characterized by environmental scanning electron microscopy (ESEM), Raman, and UV–Vis spectroscopy, and its prompt response to visible light was determined by linear sweep voltammetry (LSV). Notably, under light illumination, the hematite electrode immersed in a live cell culture was able to produce 240% more photocurrent density than that in the abiotic control of the medium, suggesting a photoenhanced extracellular electron transfer process occurring between hematite and PAO1. Different temperatures of LSV measurements showed bioelectrochemical activity in the system. Furthermore, I–t curves under various conditions demonstrated that both a direct and an indirect electron transferring process occurred between the hematite photoanode and PAO1. Moreover, the indirect electron transferring route was more dominant, which may be mainly attributed to the pyocyanin biosynthesized by PAO1. Our results have expanded our understanding in that in addition to Geobacter and Shewanella it has been shown that more microorganisms are able to perform enhanced extracellular electron transfer with semiconducting minerals under sunlight in nature.

E. Cook, Yeowon Kim, N. Grimm et al.

Proceedings of the National Academy of Sciences • 2025

Nature-Based Solutions for Urban Sustainability provides comprehensive insights on existing technologies and up-to-date advances in the field of water, wastewater and waste treatment using nature-based approaches and systems. This book highlights: Process fundamentals of nature-based solutions, including hydrodynamics, media, bacteria/media interactions and phytoremediation for pollution control, resource recovery and energy generation.Critical insights on the status, major challenges and modern engineering solutions in nature-based solutions for the treatment of rainwater, storm water, wastewater and solid waste.Advanced methods for valorisation using nature-based solutions through integration with other technologies, such as composting, anaerobic digestion and bioelectrochemical systems.Up-to-date information on modern approaches for deriving value-added operation, by combining nature-based solutions with agricultural practices such as fish farming or protein production.Case studies of nature-based solutions from countries in transition including Thailand, Vietnam, Indonesia and Philippines.This reference textbook is recommended reading for both undergraduate and graduate students pursuing degrees in environmental sciences, technologies, or engineering. It is equally useful for a broader audience including researchers, engineers, and policy makers interested in the field of nature-based solutions for urban sustainability. It is also tailored to be used as an advanced manual for practitioners and consultancies working in the field of diffuse pollution and climate change mitigation. ISBN: 9781789065008 (paperback) ISBN: 9781789065015 (eBook) ISBN: 9781789065022 (ePub)

Natalia Tyszkiewicz, J. Truu, Piotr Młynarz et al.

Frontiers in Microbiology • 2024

Bioelectrochemical systems offer unique opportunities to remove recalcitrant environmental pollutants in a net positive energy process, although it remains challenging because of the toxic character of such compounds. In this study, microbial fuel cell (MFC) technology was applied to investigate the benzene degradation process for more than 160 days, where glucose was used as a co-metabolite and a control. We have applied an inoculation strategy that led to the development of 10 individual microbial communities. The electrochemical dynamics of MFC efficiency was observed, along with their 1H NMR metabolic fingerprints and analysis of the microbial community. The highest power density of 120 mW/m2 was recorded in the final period of the experiment when benzene/glucose was used as fuel. This is the highest value reported in a benzene/co-substrate system. Metabolite analysis confirmed the full removal of benzene, while the dominance of fermentation products indicated the strong occurrence of non-electrogenic reactions. Based on 16S rRNA gene amplicon sequencing, bacterial community analysis revealed several petroleum-degrading microorganisms, electroactive species and biosurfactant producers. The dominant species were recognised as Citrobacter freundii and Arcobacter faecis. Strong, positive impact of the presence of benzene on the alpha diversity was recorded, underlining the high complexity of the bioelectrochemically supported degradation of petroleum compounds. This study reveals the importance of supporting the bioelectrochemical degradation process with auxiliary substrates and inoculation strategies that allow the communities to reach sufficient diversity to improve the power output and degradation efficiency in MFCs beyond the previously known limits. This study, for the first time, provides an outlook on the syntrophic activity of biosurfactant producers and petroleum degraders towards the efficient removal and conversion of recalcitrant hydrophobic compounds into electricity in MFCs.

E. Martínez, A. Sotres, Cristian B Arenas et al.

Energies • 2019

The effect of hydrogen pulse addition on digestion performance of sewage sludge was evaluated as a means for studying the increase in efficiency of methane production. Microbial communities were also evaluated to get an insight of the changes caused by the operational modifications of the digester. An energy evaluation of this alternative was performed considering the theoretical process of coupling bioelectrochemical systems (BES) for the treatment of wastewater along with hydrogen production and the subsequent anaerobic digestion. The addition of hydrogen to sewage sludge digestion resulted in an increase of 12% in biogas production over the control (1353 mL CH4 d−1 at an injection flow rate of 1938 mL H2 d−1). The liquid phase of the sludge reactor and the H2 supplemented one did not show significant differences, thus indicating that the application of hydrogen as the co-substrate was not detrimental. High-throughput sequencing analysis showed slight changes in archaeal relative abundance after hydrogen addition, whereas eubacterial community structure and composition revealed noteworthy shifts. The mass and energy balance indicated that the amount of hydrogen obtained from a hypothetical BES can be assimilated in the sludge digester, improving biogas production, but this configuration was not capable of covering all energy needs under the proposed scenario.

Libin Zhang, Hongling Zhang, Xinbai Jiang et al.

Desalination and Water Treatment • 2018

Cost-effective treatments of recalcitrant pollutants in wastewaters are required. The coupling degradation of p-nitrophenol (PNP) reduction in cathode and p-aminophenol (PAP, reduction product of PNP) oxidation in anode was studied in a bioelectrochemical system (BES) solely catalyzed by bacteria consortia, with no power input. In the cathode chamber, 50 mg L–1 PNP was reduced by 96.2 ± 2.4% within 96 h. PNP reduction efficiency was notably improved than that (63.8 ± 2.6%) in the abiotic cathode control. In the anode chamber, 20 mg L–1 PAP was removed by 94.0 ± 0.6% within 30 h. The reduction and oxidation peaks in cyclic voltammetry curves of the cathode and anode verified the coupled degradation process. Illumina Mi-seq sequencing revealed similar predominant bacteria with different percentages on the cathode and anode. The bacteria composition was more diverse on the anode. At the phylum level, higher prevalence of Chlorobi, Bacteroidetes, Thermi and Actinobacteria on the cathode than that on the anode were discovered. Meanwhile, Thiobacillus, Methanomethylovorans, Sphingobium and Geobacter were superior on the anode than the cathode at the genus level. Coupling treatment of PNP reduction in cathode and PAP oxidation in anode was realized in a bio-catalyzed BES. Enhanced degradation in a self-powered BES is an economical and efficient strategy for the treatment of nitroaromatic pollutants.

T. Kuleshova, P. Zhelnacheva, Z. Gasieva et al.

Russian Journal of Biological Physics and Chemisrty • 2024

The work considers the effect of the nutrient solution composition on the potential difference formation in the root environment. Identification of possible potential-generating ions in bioelectrochemical systems based on electactive plant and microbial interactions was carried out. The electropotential difference in the root environment was measured when growing lettuce with a nutrient solution with a double increased content of magnesium sulfate, potassium chloride and potassium dihydortophosphate. Changes in the electrical conductivity of nutrient solutions in the process of lettuce growing and the differences in the pH and concentrations of calcium, potassium, ammonium, nitrate ions in the upper and lower electrode areas of bioelectrochemical systems are analyzed. An increase in the concentration of potassium chloride and potassium dihydortophosphate in a nutrient solution led to a decrease in both biomass and the average voltage value to 221 mV and 188 mV, respectively, relatively characteristic of the control option with a classic solution of the potential difference 213 mV. The doubling of the magnesium sulfate concentration, on the contrary, caused an increase in the potential difference to an average value of 263 mV and an increase in biomass by more than 30% relative to control. Probably, magnesium sulfate plays a potential role in the formation of electogenic reactions in the root environment.

Fu-neng Tan

2024 International Seminar on Artificial Intelligence, Computer Technology and Control Engineering (ACTCE) • 2024

In recent years, sensors made of chitosan have become a research hotspot due to their advantages of low cost, simple preparation process, rapid response and high sensitivity. In this paper, the preparation method of chitosan sensor and its application in bioelectrochemical sensors are introduced, and its application prospect is prospected.

Silvia Bolognesi, Lluís Bañeras, Elisabet Perona-Vico et al.

Sustainable Energy & Fuels • 2022

A novel biorefinery approach, combining microbial electrosynthesis and heterotrophic microalgae, aimed at producing a biodiesel compatible oil from CO 2 .

Sara Díaz-Rullo Edreira, Silvia Barba, Ioanna A. Vasiliadou et al.

Microorganisms • 2021

Bioelectrochemical systems are a promising technology capable of reducing CO2 emissions, a renewable carbon source, using electroactive microorganisms for this purpose. Purple Phototrophic Bacteria (PPB) use their versatile metabolism to uptake external electrons from an electrode to fix CO2. In this work, the effect of the voltage (from −0.2 to −0.8 V vs. Ag/AgCl) on the metabolic CO2 fixation of a mixed culture of PPB under photoheterotrophic conditions during the oxidation of a biodegradable carbon source is demonstrated. The minimum voltage to fix CO2 was between −0.2 and −0.4 V. The Calvin–Benson–Bassham (CBB) cycle is the main electron sink at these voltages. However, lower voltages caused the decrease in the current intensity, reaching a minimum at −0.8 V (−4.75 mA). There was also a significant relationship between the soluble carbon uptake in terms of chemical oxygen demand and the electron consumption for the experiments performed at −0.6 and −0.8 V. These results indicate that the CBB cycle is not the only electron sink and some photoheterotrophic metabolic pathways are also being affected under electrochemical conditions. This behavior has not been tested before in photoheterotrophic conditions and paves the way for the future development of photobioelectrochemical systems under heterotrophic conditions.

Wei Li, Xiaohong Chen, Linshen Xie et al.

Water • 2019

Due to the deficiency of fresh water resources and the deterioration of groundwater quality worldwide, groundwater remedial technologies are especially crucial for preventing groundwater pollution and protecting the precious groundwater resource. Among the remedial alternatives, bioelectrochemical systems have unique advantages on both economic and technological aspects. However, it is rare to see a deep study focused on the information mining and visualization of the publications in this field, and research that can reveal and visualize the development trajectory and trends is scarce. Therefore, this study summarizes the published information in this field from the Web of Science Core Collection of the last two decades (1999–2018) and uses Citespace to quantitatively visualize the relationship of authors, published countries, organizations, funding sources, and journals and detect the research front by analyzing keywords and burst terms. The results indicate that the studies focused on bioelectrochemical systems for groundwater remediation have had a significant increase during the last two decades, especially in China, Germany and Italy. The national research institutes and universities of the USA and the countries mentioned above dominate the research. Environmental Science & Technology, Applied and Environmental Microbiology, and Water Research are the most published journals in this field. The network maps of the keywords and burst terms suggest that reductive microbial diversity, electron transfer, microbial fuel cell, etc., are the research hotspots in recent years, and studies focused on microbial enrichment culture, energy supply/recovery, combined pollution remediation, etc., should be enhanced in future.

Milena do Prado Ferreira, S. Yamada-Ogatta, César Ricardo Teixeira Tarley

Biosensors • 2023

Rapid transmission and high mortality rates caused by the SARS-CoV-2 virus showed that the best way to fight against the pandemic was through rapid, accurate diagnosis in parallel with vaccination. In this context, several research groups around the world have endeavored to develop new diagnostic methods due to the disadvantages of the gold standard method, reverse transcriptase polymerase chain reaction (RT-PCR), in terms of cost and time consumption. Electrochemical and bioelectrochemical platforms have been important tools for overcoming the limitations of conventional diagnostic platforms, including accuracy, accessibility, portability, and response time. In this review, we report on several electrochemical sensors and biosensors developed for SARS-CoV-2 detection, presenting the concepts, fabrication, advantages, and disadvantages of the different approaches. The focus is devoted to highlighting the recent progress of electrochemical devices developed as next-generation field-deployable analytical tools as well as guiding future researchers in the manufacture of devices for disease diagnosis.

Christopher Moß, Niklas Jarmatz, Janina Heinze et al.

ChemSusChem • 2020

Abstract In this study, the performance of electroactive bacteria (EAB), cultivated inside tubular electrode ducts, is systematically investigated to derive predictions on the behavior of EAB under conditions limited by electrochemical losses. A modeling approach is applied to assess the influence of the electrochemical losses on the electrochemical performance and scaling characteristics of complex 3D structures, such as sponges and foams. A modular flow reactor is designed that provides laminar and reproducible flow conditions as a platform for the systematic electrochemical and bioelectrochemical characterization of 3D electrodes in bioelectrochemical systems (BES). The bioelectrochemical experiments are carried out in a set of reactors incorporating cylindrical electrodes exhibiting ducts of 1 cm length and different diameters ranging from 0.1 cm up to 1 cm. Single duct calculations are extrapolated to three dimensions through geometrical considerations; trends in 3D bioanode performance are demonstrated using the resulting simplified 3D structure. The combined experimental and modeling approach constitutes a framework for future studies on systematic electrode design.

S. Ishii, H. Imachi, K. Kawano et al.

Frontiers in Energy Research • 2019

In subsurface anoxic environments, microbial communities generally produce methane as an end-product to consume organic compounds. This metabolic function is a source of biogenic methane in coastal natural gas aquifers, submarine mud volcanoes and methane hydrates. Within the methanogenic communities, hydrogenotrophic methanogens and syntrophic bacteria are converting volatile fatty acids to methane syntrophically via interspecies hydrogen transfer. Recently, direct interspecies electron transfer (DIET) between fermentative/syntrophic bacteria and electrotrophic methanogens has been proposed as an effective interspecies metabolite transfer process to enhance methane production. In this study, in order to stimulate the DIET-associated methanogenic process at deep biosphere-aquifer systems in a natural gas field, we operated a bioelectrochemical system (BES) to apply voltage between an anode and a cathode. Two single-chamber BESs were filled with seawater-based formation water collected from an onshore natural gas well, repeatedly amended with acetate, and operated with 600 mV between electrodes for 21 months, resulting in a successful conversion of acetate to methane via electrical current consumption. One reactor yielded a stable current by ~200 mA/m2 with a coulombic efficiency (CE) of >90%; however, the other reactor, which had been incidentally disconnected for 3 days, showed less electromethanogenic activity with a CE of only ~10%. The 16S rRNA gene-based community analyses showed that two methanogenic archaeal families, Methanocalculaceae and Methanobacteriaceae, were abundant in cathode biofilms that were mainly covered by single-cell-layered biofilm, implicating them as key players in the electromethanogenesis. In contrast, family Methanosaetaceae was abundant at both electrodes and the electrolyte suspension only in the reactor with less electromethanogenesis, suggesting this family was not involved in electromethanogenesis and only activated after the no electron flow event. On anodes covered by thick biofilms with filamentous networks, family Desulfuromonadaceae dominated in the early stage of the operation, while family Geobacteraceae (mainly genus Geoalkalibacter) increased their frequencies during the longer-term operation, which indicates that these families were correlated with electrode-respiring reactions. These results indicate that the BES reactors with voltage application effectively activated a subsurface DIET-related methanogenic microbiome in the natural gas field, and specific electrogenic bacteria and electromethanogenic archaea were identified within the anode and/or cathode biofilms.

Rengasamy Karthikeyan, Rajesh Singh, Arpita Bose

Journal of Industrial Microbiology and Biotechnology • 2019

Abstract Microbial electron uptake (EU) is the biological capacity of microbes to accept electrons from electroconductive solid materials. EU has been leveraged for sustainable bioproduction strategies via microbial electrosynthesis (MES). MES often involves the reduction of carbon dioxide to multi-carbon molecules, with electrons derived from electrodes in a bioelectrochemical system. EU can be indirect or direct. Indirect EU-based MES uses electron mediators to transfer electrons to microbes. Although an excellent initial strategy, indirect EU requires higher electrical energy. In contrast, the direct supply of cathodic electrons to microbes (direct EU) is more sustainable and energy efficient. Nonetheless, low product formation due to low electron transfer rates during direct EU remains a major challenge. Compared to indirect EU, direct EU is less well-studied perhaps due to the more recent discovery of this microbial capability. This mini-review focuses on the recent advances and challenges of direct EU in relation to MES.

Chen Yang, Yiheng Cao, Chuanping Feng

Water • 2025

Excessive nitrogen fertilizer use has resulted in growing nitrate contamination of groundwater. In this study, an in situ bioelectrochemical reactor (isBER) reinforced with woodchips was developed for the treatment of actual nitrate-contaminated groundwater. During the 75-day experiment, the denitrification performance, grid permeability, and microbial community structure were investigated under different flow rates and current densities. The reactor achieved a remarkable nitrate removal efficiency of 97.6% ± 0.4% and a rate of 2.09 ± 0.14 mg-N/(L·h). These results were obtained at a temperature of 18.5 ± 0.8 °C, a current density of 350 mA/m2, and a flow rate of 10 cm/d. Notably, the reactor can adapt to a wide flow-rate range of 5~20 cm/d and the operation proceeded smoothly without any blockages. Furthermore, the cathode module demonstrated enrichment of hydrogen autotrophic denitrifying bacteria (Pseudomonas, Stenotrophomonas) and heterotrophic denitrifying bacteria (Brucella, Enterobacteriaceae). Conversely, the anode module exhibited relatively high enrichment levels of aerobic microorganisms and lignin-degrading bacteria (Cellvibrio). The research results can provide novel insights and technical support for in situ remediation of groundwater nitrate contamination.

Raúl Mateos, Raúl Alonso, Adrián Escapa et al.

Materials • 2017

The development and practical implementation of bioelectrochemical systems (BES) requires an in-depth characterisation of their components. The electrodes, which are critical elements, are usually built from carbon-based materials due to their high specific surface area, biocompatibility and chemical stability. In this study, a simple methodology to electrochemically characterise carbon-based electrodes has been developed, derived from conventional electrochemical analyses. Combined with classical electrochemical theory and the more innovative fractal geometry approach, our method is aimed at comparing and characterising the performance of carbon electrodes through the determination of the electroactive surface and its fractal dimension. Overall, this methodology provides a quick and easy method for the screening of suitable electrode materials to be implemented in BES.

Bonyoung Koo, S. Jung

Journal of Korean Society of Environmental Engineers • 2022

Currently, gray hydrogen and blue hydrogen are widely recognized as renewable energy, but in reality, they are made from fossil fuels. The most important task to achieve the hydrogen-based society is the development of economic green hydrogen production technology. Microbial electrolysis cell (MEC) is a next-generation energy-producing wastewater treatment technology that treats renewable organic wastewater and simultaneously produces the ultimate green hydrogen. For hydrogen production in MFC, it is necessary to input electrical energy into MEC. However, that energy is all covered by the energy produced by the MEC. Therefore, hydrogen production in MEC can be defined as the ultimate green hydrogen. This review contains an in-depth summary and analysis of the principles and feasibility of MEC technology, the composition and shape of MEC, electrode materials, and practical application cases in various types of wastewaters. Furthermore, compatibility and scalability with other environmental systems were reviewed at the pilot scale. Based on this, the technical limitations of MEC were diagnosed and future research directions for the practical application of MEC technology were suggested.

Kuanchang He, Wei Li, Longxiang Tang et al.

Environmental Science & Technology • 2022

Hydrogen gas (H2) is an attractive fuel carrier due to its high specific enthalpy; moreover, it is a clean source of energy because in the combustion reaction with oxygen (O2) it produces water as the only byproduct. The microbial electrolysis cell (MEC) is a promising technology for producing H2 from simple or complex organics present in wastewater and solid wastes. Methanogens and non-archaeal methane (CH4)-producing microorganisms (NAMPMs) often grow in the MECs and lead to rapid conversion of produced H2 to CH4. Moreover, non-archaeal methane production (NAMP) catalyzed by nitrogenase of photosynthetic bacteria was always overlooked. Thus, suppression of CH4 production is required to enhance H2 yield and production rate. This review comprehensively addresses the principles and current state-of-the-art technologies for suppressing methanogenesis and NAMP in MECs. Noteworthy, specific strategies aimed at the inhibition of methanogenic enzymes and nitrogenase could be a more direct approach than physical and chemical strategies for repressing the growth of methanogenic archaea. In-depth studies on the multiomics of CH4 metabolism can possibly provide insights into sustainable and efficient approaches for suppressing metabolic pathways of methanogenesis and NAMP. The main objective of this review is to highlight key concepts, directions, and challenges related to boosting H2 generation by suppressing CH4 production in MECs. Finally, perspectives are briefly outlined to guide and advance the future direction of MECs for production of high-purity H2 based on genetic and metabolic engineering and on the interspecific interactions.

Yanhui Liu, Xingkun Wang, Bolin Zhao et al.

Chemistry – A European Journal • 2019

Nonprecious-metal-based electrocatalysts with low cost, high activity, and stability are considered as one of the most promising alternatives to Pt-based catalysts for the oxygen reduction reaction (ORR). Herein, an economical and easy-to-fabricate catalyst is developed, that is, Fe/Fe3 C embedded in N-doped hollow carbon spheres (Fe/Fe3 C/NHCS), which gave the half-wave potential of 0.84 V in 0.1 m KOH, similar to the commercial Pt/C catalyst. Surprisingly, the favorable ORR performance of the as-prepared catalyst was obtained in both acidic and neutral conditions with almost a four-electron pathway and low H2 O2 yield, which desirable the development of the proton exchange membrane (PEM) and microbial electrolysis cell (MEC) technology. Additionally, the obtained catalyst demonstrated better long-term stability and high methanol tolerance over a wide range of pH. These features could be mainly attributed to the synergistic effect between Fe/Fe3 C and Fe-Nx sites, the hollow structure with mesopores, and the well-dispersed Fe/Fe3 C nanoparticles owing to the existence of the abundant hydrophilic groups within the HCS precursor. As such, designing an efficient and cheap ORR catalyst that can operate at alkaline, acidic, and neutral solutions is highly desirable, yet challenging.

L. F. Leon-Fernandez, X. Dominguez-Benetton, J. Villaseñor Camacho et al.

Environmental Microbiology Reports • 2023

Abstract This work proves the feasibility of dechlorinating 2,4‐D, a customary commercial herbicide, using cathodic electrocatalysis driven by the anodic microbial electrooxidation of sodium acetate. A set of microbial electrochemical systems (MES) were run under two different operating modes, namely microbial fuel cell (MFC) mode, with an external resistance of 120 Ω, or microbial electrolysis cell (MEC) mode, by supplying external voltage (0.6 V) for promoting the (bio)electrochemical reactions taking place. When operating the MES as an MFC, 32% dechlorination was obtained after 72 h of treatment, which was further enhanced by working under MEC mode and achieving a 79% dechlorination. In addition, the biodegradability (expressed as the ratio BOD/COD) of the synthetic polluted wastewater was tested prior and after the MES treatment, which was improved from negative values (corresponding to toxic effluents) up to 0.135 in the MFC and 0.453 in the MEC. Our MES approach proves to be a favourable option from the point of view of energy consumption. Running the system under MFC mode allowed to co‐generate energy along the dechlorination process (−0.0120 kWh mol−1), even though low removal rates were attained. The energy input under MEC operation was 1.03 kWh mol−1—a competitive value compared to previous works reported in the literature for (non‐biological) electrochemical reactors for 2,4‐D electrodechlorination.