Alka Kaushik, S.K. Jadhav

NewBioWorld • 2023

This review article discussed about the food waste as a source of bioelectrical energy. Every year the global energy demand increases. While petroleum products currently supply much of this demand, the increasing difficulty of sustained supply and the associated problems of pollution and global warming creates unbalanced energy management and require power sources that are able to sustain for longer periods. Renewable energy generation and waste disposal are two key challenges for the sustainability of future societies. Microbial fuel cells (MFCs) as an alternative renewable technology can run in solid phase and capture bioelectricity from food waste. Food waste being readily available is found to be the potential source for bioelectricity production by optimizing several important factors are optimized, such as the type, number and quality of electrodes, type and amount of substrate, microorganism community, system configuration, and different parameters which increases the amount of electricity generated. Solid microbial fuel cells (SMFCs) were reported to produce relatively small amounts of energy compared with other substrates, but SMFCs are still promising to achieve energy requirement of the future. So this review demonstrates the works of different scientist who potentially produced bioelectricity and looking further for improvements.

Lili Chen, Xiangjian Zheng, Kun Zhang et al.

Journal of hazardous materials • 2023

Nitrate addition is a biostimulation technique that can improve both the oxidation of acid volatile sulfide (AVS) through autotrophic denitrification and the biodegradation of polycyclic aromatic hydrocarbons (PAHs) via heterotrophic denitrification. However, during the remediation, parts of the dissolved nitrate in the sediment migrates from the sediment to the overlying water, leading to the loss of effective electron acceptor. To overcome this limitation, a combined approached was proposed, which involved nitrocellulose addition and a microbial fuel cell (MFC). Results indicated the nitrate could be slowly released and maintained at a higher concentration over long term. In the combined system, the removal efficiencies of PAHs and AVS were 71.56% and 89.76%, respectively. Furthermore, the voltage attained for the MFC-nitrocellulose treatment was maintained at 146.1 mV on Day 70, which was 5.37 times higher than that of the MFC-calcium nitrate treatment. Sediments with nitrocellulose resulted in lower levels of nitrate and ammonium in the overlying water. Metagenomic results revealed that the combined technology improved the expression of nitrogen-cycling genes. The introduction of MFC inhibited sulfide regeneration during incubation by suppressing the enzyme activity like EC4.4.1.2. The enhanced biostimulation provided potential for in-situ bioremediation utilizing MFC coupled with slow-released nitrate (i.e., nitrocellulose) treatment.

Shuting Shen, Longxiao Xie, Rui Wan et al.

Chemosphere • 2023

The presence of non-reactive phosphorus (NRP) in environmental waters presents a potential risk of eutrophication and poses challenges for the removal of all phosphorus (P) fractions. This study presents the first investigation on the removal performance and mechanism of three model NRP compounds, sodium tripolyphosphate (STPP), adenosine 5'-monophosphate (AMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), in the sediment microbial fuel cell-floating treatment wetland (SMFC-FTW). Coupling SMFC with plants proved to be effective at removing NRP via electrochemical oxidation and plant uptake, particularly the challenging-to-degrade phosphonates that contain C-P bonds. Compared with the control group, the removal efficiencies of the model NRP in SMFC were observed to increase by 11.9%-20.8%. SMFC promoted the conversion of NRP to soluble reactive phosphorus (sRP) and the transfer of P to sediment. Furthermore, the electrochemical process enhanced both plant growth and P uptake, and increased P assimilation by 72.6%. The presence of plants in the bioelectrochemical system influenced the occurrence and fate of P by efficiently assimilating sRP and supporting microbial transformation of NRP. Consequently, plants enhanced the removal efficiencies of all P fractions in the overlying water. This study demonstrated that SMFC-FTW is a promising technology to remove various NRP species in environmental waters.

Benhang Li, Dandan Xu, Li Feng et al.

Environmental pollution (Barking, Essex : 1987) • 2022

Energy resource scarcity and sediment pollution perniciousness have become enormous challenges, to which research has been focused on energy recovery and recycle technologies to solve both above problems. The organic matter stored in anoxic sediments of freshwater ecosystem represents a tremendous potential energy source. The system of aquatic plant coupled with sediment microbial fuel cell (AP-SMFC) has attracted much attention as a more feasible, economical and eco-friendly way to remediate sediment and surface water and generate electricity. However, the research on AP-SMFC has only been carried out in the last decade, and relevant studies have not been well summarized. In this review, the advances and prospects on AP-SMFC were systematically introduced. Firstly, the annual publication counts and keywords co-occurrence cluster of AP-SMFC were identified and visualized by resorting to the CiteSpace software, and the result showed that the research on AP-SMFC increased significantly in the last decade on the whole and will continue to increase. The bibliometric results provided valuable references and information on potential research directions for future studies. And then, the research progress and reaction mechanism of AP-SMFC were systematically described. Thirdly, the performance of AP-SMFC, including nutrients removal, organic contaminants removal, and electricity generation, was systematically summarized. AP-SMFC can enhance the removal of pollutants and electricity generation compared with SMFC without AP, and is considered to be an ideal technology for pollutants removal and resource recovery. Finally, the current challenges and future perspectives were summarized and prospected. Therefore, the review could serve as a guide for the new entrants to the field and further development of AP-SMFC application.

Chong Xu, Shiquan Sun, Yifu Li et al.

The Science of the total environment • 2023

Sediment is the internal and external source of water environment pollution, so sediment remediation is the premise of water body purification. Sediment microbial fuel cell (SMFC) can remove the organic pollutants in sediment by electroactive microorganisms, compete with methanogens for electrons, and realize resource recycling, methane emission inhibiting and energy recovering. Due to these characteristics, SMFC have attracted wide attention for sediment remediation. In this paper, we comprehensively summarized the recent advances of SMFC in the following areas: (1) The advantages and disadvantages of current applied sediment remediation technologies; (2) The basic principles and influencing factors of SMFC; (3) The application of SMFC for pollutant removal, phosphorus transformation and remote monitoring and power supply; (4) Enhancement strategies for SMFC in sediments remediation such as SMFC coupled with constructed wetland, aquatic plant and iron-based reaction. Finally, we have summarized the drawback of SMFC and discuss the future development directions of applying SMFC for sediment bioremediation.

R Sudarman, A Zaeni, I Usman et al.

Journal of Physics: Conference Series • 2020

Abstract Marine sediments of Kendari Bay has the potential as an alternative source of electrical energy through sediment microbial fuel cell (SMFC) due to the high level of sedimentation. This study aims to optimize the amount of electrical voltage that can be generated through the SMFC system using stacked SMFC in the form of a series connection. The research methods include determining the sampling location, physical-chemical properties measurement of sediments, SMFC assembly (single and stacked SMFC), and electrical voltage measurement. Three station points representing the overall condition of Kendari Bay are determined as sampling locations. The result shows that there was a decrease in the organic matter content of the sediment substrate after the use of SMFC namely organic carbon from 2.78 percent to be 2.68 percent due to microbial activity in sediments. The single SMFC from station 2 (S2) can produce the maximum electrical voltage of 438 mV which then optimized using stacked SMFC in series connection. The maximum electrical voltage of 2.174V can be obtained using stacked SMFC. These results show that marine sediments of Kendari Bay is interesting as an alternative energy source through SMFC and stacked SMFC could optimize the amount of electrical voltage from single SMFC.

Xiuping Zhu, Bruce E Logan

Bioresource technology • 2013

Mineral carbonation can be used for CO2 sequestration, but the reaction rate is slow. In order to accelerate mineral carbonation, acid generated in a microbial electrolysis desalination and chemical-production cell (MEDCC) was examined to dissolve natural minerals rich in magnesium/calcium silicates (serpentine), and the alkali generated by the same process was used to absorb CO2 and precipitate magnesium/calcium carbonates. The concentrations of Mg(2+) and Ca(2+) dissolved from serpentine increased 20 and 145 times by using the acid solution. Under optimal conditions, 24 mg of CO2 was absorbed into the alkaline solution and 13 mg of CO2 was precipitated as magnesium/calcium carbonates over a fed-batch cycle (24h). Additionally, the MEDCC removed 94% of the COD (initially 822 mg/L) and achieved 22% desalination (initially 35 g/L NaCl). These results demonstrate the viability of this process for effective CO2 sequestration using renewable organic matter and natural minerals.

A Y Goren, D N Eskisoy, S Genisoglu et al.

The Science of the total environment • 2024

The scarcity and contamination of freshwater resources are extremely critical issues today, and the expansion of water reuse has been considered as an option to decrease its impact. Therefore, the reuse of microbial desalination (MDC)-treated spent geothermal brine for agricultural purposes arises as a good solution to prevent water contamination and provide sustainable water usage. In this study, the potential of treated spent geothermal water from MDC system as a nutrient solution for the hydroponic cultivation of lettuce was evaluated. The effects of different water samples (Hoagland solution (R1) as a control, MDC-treated water (R2), 1:1, v/v mixture of MDC-treated water and Hoagland solution (R3), 4:1, v/v mixture of MDC-treated water and Hoagland solution (R4), and tap water (R5)) on lettuce growth were considered. The application of R3 and R4 samples for hydroponic lettuce cultivation was promising since the lettuce plants uptake sufficient nutrients for their growth and productivity with low toxic metal concentrations. In addition, the chlorophyll-a, chlorophyll-b, and carotene contents of lettuce were in the range of 1.045-2.391 mg/g, 0.761-1.986 mg/g, and 0.296-0.423 mg/g in different water samples, respectively. The content of chlorophyll-a was highest in R1 (2.391 mg/g), followed by R3 (2.371 mg/g). Furthermore, the health risk assessment of heavy metal accumulations in the lettuce plants cultivated in the various water samples was determined. Results showed that heavy metal exposure via lettuce consumption is unlikely to suffer noticeable adverse health problems with values below the permissible limit value.

Soheil Aber, Zhining Shi, Ke Xing et al.

Global challenges (Hoboken, NJ) • 2022

In view of increasing threats arising from the shortage of fresh water, there is an urgent need to propose sustainable technologies for the exploitation of unconventional water sources. As a derivative of microbial fuel cells (MFCs), microbial desalination cell (MDC) has the potential of desalinating saline/brackish water while simultaneously generating electricity, as well as treating wastewater. Therefore, it is worth investigating its practicability as a potential sustainable desalination technology. This review article first introduces the fundamentals and annual trends of MDCs. The desalination of diverse types of solutions using MDCs along with their life cycle impact assessment (LCIA)  and economic analysis is studied later. Finally, limitations and areas for improvement, prospects, and potential applications of this technology are discussed. Due to the great advantages of MDCs, improving their design, building materials, efficiency, and throughput will offer them as a significant alternative to the current desalination technologies.

Catarina M Paquete, Miriam A Rosenbaum, Lluís Bañeras et al.

Bioresource technology • 2021

Electroactive microorganisms can exchange electrons with other cells or conductive interfaces in their extracellular environment. This property opens the way to a broad range of practical biotechnological applications, from manufacturing sustainable chemicals via electrosynthesis, to bioenergy, bioelectronics or improved, low-energy demanding wastewater treatments. Besides, electroactive microorganisms play key roles in environmental bioremediation, significantly impacting process efficiencies. This review highlights our present knowledge on microbial interactions promoting the communication between electroactive microorganisms in a biofilm on an electrode in bioelectrochemical systems (BES). Furthermore, the immediate knowledge gaps that must be closed to develop novel technologies will also be acknowledged.

S. ThamizhSuganya, P. Balaganesan, L. Rajendran

International Journal of Advanced Research in Science, Communication and Technology • 2021

Mathematical modeling of biohydrogen production in microbial electrolysis cell reactor is discussed. This study explains the mathematical model for the production of hydrogen from a wastewater batch reactor, and it contains a system of non-linear equations. The non-linear differential equation of this model is solved by the Homotopy perturbation method. The approximate analytical expression of this model, concentration of substrate, anodophilic microorganisms, acetoclastic microorganism, hydrogenotrophic microorganisms, and Oxidized mediator are obtained. The effect of various values of the parameters on the reactions is discussed. The analytical solutions are also compared with simulation results and satisfactory the agreement is noted.

Li-Li Wan, Xiao-Jing Li, Guo-Long Zang et al.

RSC Advances • 2014

Solar energy, a microbial electrolysis cell (MEC) and a microbial fuel cell were combined as a new MEC system for hydrogen production.

Chunyan Li, Dongchao Guo, Yan Dang et al.

Journal of environmental management • 2023

Bioelectrochemical Systems (BESs) leverage microbial metabolic processes to either produce electricity by degrading organic matter or consume electricity to assist metabolism, and can be used for various applications such as energy production, wastewater treatment, and bioremediation. Given the intricate mechanisms of BESs, the application of artificial intelligence (AI)-based methods have been proposed to enhance the performance of BESs due to their capability to identify patterns and gain insights through data analysis. This review focuses on the analysis and comparison of AI algorithms commonly used in BESs, including artificial neural network (ANN), genetic programming (GP), fuzzy logic (FL), support vector regression (SVR), and adaptive neural fuzzy inference system (ANFIS). These algorithms have different features, such as ANN's simple network structure, GP's use in the training process, FL's human-like thought process, SVR's high prediction accuracy and robustness, and ANFIS's combination of ANN and FL features. The AI-based methods have been applied in BESs to predict microbial communities, products or substrates, and reactor performance, which can provide valuable information and improve system efficiency. Limitations of AI-based methods for predicting and optimizing BESs and recommendations for future development are also discussed. This review demonstrates the potential of AI-based methods in optimizing BESs and provides valuable information for the future development of this field.

Xue Ning, Richen Lin, Richard O'Shea et al.

iScience • 2021

Biomethane is suggested as an advanced biofuel for the hard-to-abate sectors such as heavy transport. However, future systems that optimize the resource and production of biomethane have yet to be definitively defined. This paper assesses the opportunity of integrating anaerobic digestion (AD) with three emerging bioelectrochemical technologies in a circular cascading bioeconomy, including for power-to-gas AD (P2G-AD), microbial electrolysis cell AD (MEC-AD), and AD microbial electrosynthesis (AD-MES). The mass and energy flow of the three bioelectrochemical systems are compared with the conventional AD amine scrubber system depending on the availability of renewable electricity. An energy balance assessment indicates that P2G-AD, MEC-AD, and AD-MES circular cascading bioelectrochemical systems gain positive energy outputs by using electricity that would have been curtailed or constrained (equivalent to a primary energy factor of zero). This analysis of technological innovation, aids in the design of future cascading circular biosystems to produce sustainable advanced biofuels.

Xi Chen, Peng Liang, Xiaoyuan Zhang et al.

Bioresource technology • 2015

Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization.

S V Ramanaiah, K Chandrasekhar, Cristina M Cordas et al.

Environmental pollution (Barking, Essex : 1987) • 2023

Producing food by farming and subsequent food manufacturing are central to the world's food supply, accounting for more than half of all production. Production is, however, closely related to the creation of large amounts of organic wastes or byproducts (agro-food waste or wastewater) that negatively impact the environment and the climate. Global climate change mitigation is an urgent need that necessitates sustainable development. For that purpose, proper agro-food waste and wastewater management are essential, not only for waste reduction but also for resource optimization. To achieve sustainability in food production, biotechnology is considered as key factor since its continuous development and broad implementation will potentially benefit ecosystems by turning polluting waste into biodegradable materials; this will become more feasible and common as environmentally friendly industrial processes improve. Bioelectrochemical systems are a revitalized, promising biotechnology integrating microorganisms (or enzymes) with multifaceted applications. The technology can efficiently reduce waste and wastewater while recovering energy and chemicals, taking advantage of their biological elements' specific redox processes. In this review, a consolidated description of agro-food waste and wastewater and its remediation possibilities, using different bioelectrochemical-based systems is presented and discussed together with a critical view of the current and future potential applications.

Durga Madhab Mahapatra, Puranjan Mishra, Sveta Thakur et al.

Trends in biotechnology • 2021

Bioelectrochemical systems (BESs) are highly evolved and sophisticated systems that produce bioenergy via exoelectrogenic microbes. Artificial intelligence (AI) helps to understand, relate, model, and predict both process parameters and microbial diversity, resulting in higher performance. This approach has revolutionized BESs through highly advanced computational algorithms that best suit the systems' architecture.

Tianwen Zheng, Jin Li, Yaliang Ji et al.

Frontiers in bioengineering and biotechnology • 2019

Bioelectrochemical systems are revolutionary new bioengineering technologies which integrate microorganisms or enzymes with the electrochemical method to improve the reducing or oxidizing metabolism. Generally, the bioelectrochemical systems show the processes referring to electrical power generation or achieving the reducing reaction with a certain potential poised by means of electron transfer between the electron acceptor and electron donor. Researchers have focused on the selection and optimization of the electrode materials, design of electrochemical device, and screening of electrochemically active or inactive model microorganisms. Notably, all these means and studies are related to electron transfer: efflux and consumption. Thus, here we introduce the basic concepts of bioelectrochemical systems, and elaborate on the extracellular and intracellular electron transfer, and the hypothetical electron transfer mechanism. Also, intracellular energy generation and coenzyme metabolism along with electron transfer are analyzed. Finally, the applications of bioelectrochemical systems and the prospect of microbial electrochemical technologies are discussed.

Jin Sun, Hongrui Cao, Zejie Wang

Processes • 2020

Nitrogenous compounds attract great attention because of their environmental impact and harmfulness to the health of human beings. Various biological technologies have been developed to reduce the environmental risks of nitrogenous pollutants. Bioelectrochemical systems (BESs) are considered to be a novel biological technology for removing nitrogenous contaminants by virtue of their advantages, such as low energy requirement and capacity for treating wastewaters with a low C/N ratio. Therefore, increasing attention has been given to carry out biological processes related to nitrogen removal with the aid of cathodic biofilms in BESs. Prior studies have evaluated the feasibility of conventional biological processes including nitrification, denitrification, and anaerobic ammonia oxidation (anammox), separately or combined together, to remove nitrogenous compounds with the help of BESs. The present review summarizes the progress of developments in BESs in terms of the biological process, cathodic biofilm, and affecting factors for efficient nitrogen removal.

Atieh Ebrahimi, Muttucumaru Sivakumar, Craig McLauchlan

Journal of environmental management • 2020

The past decade has seen the rapid development of constructed wetland-microbial fuel cell (CW-MFC) technology in many aspects. The first publication on the combination of constructed wetland (CW) and microbial fuel cell (MFC) appeared in 2012, subsequently, research on the subject has grown exponentially to improve the performance of CW-MFCs in their dual roles of wastewater treatment and power generation. Although significant research has been conducted on this technology worldwide, a comprehensive and critical review of effective controlling parameters is lacking. More broadly, research is needed to draw up-to-date conclusions on recent developments and to identify knowledge gaps for further studies. This review paper systematically enumerates and reviews research studies published in this area to determine the key design factors and their role in CW-MFC performance. Moreover, a taxonomy of all CW-MFC design parameters has been synthesised from the literature. Importantly, this original work provides a comprehensive conceptual framework for future researchers, designers, builders, and users to understand CW-MFC technology. Within the taxonomy, parameters are placed in three main categories (physical/environmental, chemical, and biological/electrochemical) and comprehensive details are given for each parameter. Finally, a comprehensive summary of the parameters has been tabulated showing their impact on CW-MFC operation, design recommendations from literature, and the significant research gaps that this review has identified within the existing literature. It is hoped that this paper will provide a clear and rich picture of this technology at its current stage of development and furthermore, will facilitate a deeper understanding of CW-MFC performance for long-term and large-scale development.

Kavya Arun Dwivedi, Song-Jeng Huang, Chin-Tsan Wang

Chemosphere • 2021

The conflict between climate change and growing global energy demand is an immense sustainability challenge that requires noteworthy scientific and technological developments. Recently the importance of microbial fuel cell (MFC) on this issue has seen profound investigation due to its inherent ability of simultaneous wastewater treatment, and power production. However, the challenges of economy-related manufacturing and operation costs should be lowered to achieve positive field-scale demonstration. Also, a variety of different field deployments will lead to improvisation. Hence, this review article discusses the possibility of integration of MFC technology with various technologies of recent times leading to advanced sustainable MFC technology. Technological innovation in the field of nanotechnology, genetic engineering, additive manufacturing, artificial intelligence, adaptive control, and few other hybrid systems integrated with MFCs is discussed. This comprehensive and state-of-the-art study elaborates hybrid MFCs integrated with various technology and its working principles, modified electrode material, complex and easy to manufacture reactor designs, and the effects of various operating parameters on system performances. Although integrated systems are promising, much future research work is needed to overcome the challenges and commercialize hybrid MFC technology.

Payel Choudhury, Uma Shankar Prasad Uday, Tarun Kanti Bandyopadhyay et al.

Bioengineered • 2017

There is an urgent need to find an environment friendly and sustainable technology for alternative energy due to rapid depletion of fossil fuel and industrialization. Microbial Fuel Cells (MFCs) have operational and functional advantages over the current technologies for energy generation from organic matter as it directly converts electricity from substrate at ambient temperature. However, MFCs are still unsuitable for high energy demands due to practical limitations. The overall performance of an MFC depends on microorganism, appropriate electrode materials, suitable MFC designs, and optimizing process parameters which would accelerate commercialization of this technology in near future. In this review, we put forth the recent developments on microorganism and electrode material that are critical for the generation of bioelectricity generation. This would give a comprehensive insight into the characteristics, options, modifications, and evaluations of these parameters and their effects on process development of MFCs.

Khaled Elmaadawy, Bingchuan Liu, Jingping Hu et al.

Journal of environmental sciences (China) • 2019

Over half of century, sanitary landfill was and is still the most economical treatment strategy for solid waste disposal, but the environmental risks associated with the leachate have brought attention of scientists for its proper treatment to avoid surface and ground water deterioration. Most of the treatment technologies are energy-negative and cost intensive processes, which are unable to meet current environmental regulations. There are continuous demands of alternatives concomitant with positive energy and high effluent quality. Microbial fuel cells (MFCs) were launched in the last two decades as a potential treatment technology with bioelectricity generation accompanied with simultaneous carbon and nutrient removal. This study reviews capability and mechanisms of carbon, nitrogen and phosphorous removal from landfill leachate through MFC technology, as well as summarizes and discusses the recent advances of standalone and hybrid MFCs performances in landfill leachate (LFL) treatment. Recent improvements and synergetic effect of hybrid MFC technology upon the increasing of power densities, organic and nutrient removal, and future challenges were discussed in details.

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Global NEST Journal • 2019

<p>The main aim of this study is to investigate the simultaneous azo dye removal and bioelectricity production at sulfate reducing conditions in continuously-fed dual-chamber microbial fuel cell (MFC). Initially, optimization of sulfate reduction was performed at different sulfate concentrations (100-900 mg/L) and the constant COD of 1000 mg/L, corresponding to COD/sulfate ratio of 1.11-10, and varying HRT of 12-48h. Optimum COD/sulfate ratio and HRT was found 1.66 and 36h, respectively, corresponding to 96% COD removal, 44% sulfate removal and yielded about 24 W/m2 power density. Further, MFC was fed with azo dye containing (50-1000 mg/L) simulated wastewater to evaluate dye removal performance of sulfate reducing bacteria. Addition of azo dye slightly enhanced the power production to 26 W/m2, the highest value obtained during our study, compared to azo dye lacking study periods. Sulfate and COD removals were adversely affected at azo dye concentrations over 300 mg/L and 150 mg/L, respectively. Additionally, color removal performance of MFC was excellent however, chemical azo dye reduction out-competed with enzymatic reduction at high azo dye levels (>500 mg/L) leading to a poor sulfate (<15%) and COD (<45%) removal and recovery of azo dye reduction efficiency to 91%.</p>

Elif DURNA PİŞKİN, Nevim NevimGENÇ

Research Square • 2022

Abstract In microbial fuel cells (MFC), oxidation and reduction processes occur simultaneously. In this study, the operating conditions affecting oxidation-reduction and electricity generation 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 cm 2 , cathode conductivity of 20 µs/cm), 177.031 mW/m 2 power density, 7.50% coulombic efficiency, 91.266% azo dye removal efficiency and 21.612% COD removal efficiency were obtained. From the 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. With the polarization curve, it has been determined that the maximum power density is 145.11 mW/m 2 and the internal resistance of the optimum MFC system is 243.3 Ω. The cyclic voltammogram performed with the optimum experiment was associated with oxidation and reduction reactions.

Aliyu, A. A., Dahiru, R.

UMYU Journal of Microbiology Research (UJMR) • 2024

Study’s Novelty/Excerpt This study presents an approach to enhancing microbial fuel cell (MFC) performance by employing phototrophic bacteria (PTB) and sustainable electrode materials, specifically a 3D anode electrode fabricated from reduced graphene oxide (rGO) and nickel (Ni) foam. By integrating morphological, biochemical, and molecular techniques to identify the electrochemically active PTB, the research achieved a significant eight-fold increase in power density using rGO-Ni electrodes compared to conventional Ni electrodes. This work underscores the potential of utilizing sustainable materials and PTB to improve MFC efficiency and economic viability, offering a promising direction for sustainable bioelectricity generation. Full Abstract Over the past years, despite intensified research on microbial fuel cells (MFC), low power densities were recorded, reducing the productivity and economic viability of the process. This necessitated testing various MFC configurations, fabricating various electrodes, and evaluating various substrate types and species of electrogenic microorganisms to improve MFC performance. Despite the dual advantage of phototrophic bacteria (PTB), metabolizing organic waste substances and generating electricity, less research was conducted on the bacterium. Although a significant amount of energy is generated using unsustainable (fossil-based) materials in electrode fabrication, this study focuses on using sustainable materials like carbon cloth and graphite to fabricate a 3D anode electrode to exploit the maximum energy generated by PTB. The PTB used in this study was identified through morphological characteristics and biochemical tests (catalase and oxidase) and confirmed using a molecular technique: 16S rRNA sequencing. Preliminary results indicated that the PTB was gram-negative, spherical in shape, non−motile, and facultatively anaerobic bacterium. Analysis of the 16S rRNA partial sequence was conducted in GenBank databases. 100 significant sequences with the lowest and highest similarities of 84.10% and 98.76% were recorded, respectively. Of these, 13 strains had the highest similarities of >90%, all belonging to the genus Dysgonomonas, with D. oryzarvi Dy73 (98.76%) as the closest. Reduced graphene oxide (rGO) used as the anode was prepared using Hummer’s method by depositing the rGO on nickel (Ni) foam which changed the colour of Ni from grey to black after depositing and annealing. In addition to the SEM images, which showed a continuous multi−layered 3D scaffold on the Ni, the cyclic voltammetry (CV) analyses indicated an increase in the electrochemical activities of the rGO−Ni electrode compared to Ni. The CV also confirmed the bacterium to be electrochemically active. The 100 mL glucose−fed two−chamber MFC were separately run with the Ni and rGO–Ni as anode electrodes in a batch mode for 11 days, while carbon cloth was used as the cathode for both runs. An approximate 0.58 W/m2 power density was recorded for Ni, but eight−fold of Ni’s, 4.9 W/m2was generated by rGO−Ni. The study demonstrated that using fabricated 3D rGO–Ni as anode electrode can increase the microbial adhesion and power density of bacterium in MFC, thereby providing a more applicable and sustainable alternative to bioelectricity generation.

Korneel Rabaey, Willy Verstraete

Trends in Biotechnology • 2005

Deepak Pant, Gilbert Van Bogaert, Ludo Diels et al.

Bioresource Technology • 2010

Bruce E. Logan, Ruggero Rossi, Ala’a Ragab et al.

Nature Reviews Microbiology • 2019

A vast array of microorganisms from all three domains of life can produce electrical current and transfer electrons to the anodes of different types of bioelectrochemical systems. These exoelectrogens are typically iron-reducing bacteria, such as Geobacter sulfurreducens, that produce high power densities at moderate temperatures. With the right media and growth conditions, many other microorganisms ranging from common yeasts to extremophiles such as hyperthermophilic archaea can also generate high current densities. Electrotrophic microorganisms that grow by using electrons derived from the cathode are less diverse and have no common or prototypical traits, and current densities are usually well below those reported for model exoelectrogens. However, electrotrophic microorganisms can use diverse terminal electron acceptors for cell respiration, including carbon dioxide, enabling a variety of novel cathode-driven reactions. The impressive diversity of electroactive microorganisms and the conditions in which they function provide new opportunities for electrochemical devices, such as microbial fuel cells that generate electricity or microbial electrolysis cells that produce hydrogen or methane.

Wenjie Liu

American Journal of Bioscience and Bioengineering • 2014

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Inorganic chemistry • 2026

Copper efflux oxidase (CueO) is involved in copper homeostasis in Escherichia coli by catalyzing the oxidation of cuprous ion (Cu + ) to cupric ion (Cu 2+ ). CueO has been studied as a direct electron transfer (DET)-type bioelectrocatalyst owing to its high dioxygen-reducing activity. Our previous study demonstrated reductive inactivation in the DET-type bioelectrocatalysis of CueO in the presence of Cu 2+ , which was known to facilitate substrate oxidation in solution. Considering the structural data, we hypothesized that eighth bound copper (Cu8) induced reductive inactivation. CueO variants deleting putative Cu8 ligands (His145, His406, and Met417) were characterized bioelectrochemically. As expected, the inactivation was significantly suppressed in H145A while being slightly suppressed in the H406A variant. In contrast, Cu 2+ tolerance was slightly decreased in the M417A variant. These results indicate that His145 and His406 are the main and auxiliary ligands, respectively, of Cu8 that induce reductive inactivation, whereas Met417 might contribute to stabilizing the Cu8 coordination sphere. Furthermore, kinetic analysis revealed that the deletion of Cu8 ligands affected both the binding and redox kinetics of the enzyme-substrate-copper complex. Additionally, Cu8-induced inactivation was observed using an enzymatic assay in solution. Therefore, reductive inactivation likely occurs in concert with biological Cu + oxidation, which may contribute to regulating the Cu 2+ /Cu + ratio.

[object Object], [object Object], [object Object] et al.

RSC advances • 2026

This study explores the use of ternary system nanocomposites to degrade methyl orange (MO) dye in water as well as assesses their antibacterial properties. For this purpose, the co-precipitation process was adopted to synthesize strontium oxide (SrO) doped with a fixed amount (3 wt%) of polyethylene glycol (PEG) as a capping agent, and various weight ratios (2 and 4 wt%) of cesium (Cs) were added to the binary system (PEG-SrO). Advanced characterization techniques were employed to analyze the various properties of the resulting materials. XRD unveiled the cubic crystal structure of SrO, while TEM revealed randomly oriented nanorods in the pristine sample. The optimum sample (2% Cs/PEG-SrO) demonstrated efficient catalytic activity (CA) in degrading MO dye. The 4% Cs/PEG-SrO sample showed significant bactericidal efficacy against Escherichia coli ( E. coli ), exhibiting inhibition zones ranging from 2.05 to 6.15 mm at higher concentrations. Furthermore, the computational findings align with the experimental data, offering strong evidence for the microbial effectiveness of Cs/PEG-SrO in hindering DNA gyrase in E. coli .

[object Object], [object Object], [object Object] et al.

Analytical chemistry • 2026

Oxidative stress has been recognized as a pivotal mechanism for disrupting cellular ion homeostasis and contributes to the pathogenesis of associated conditions, including alcoholic liver disease (ALD). The real-time and accurate detection of cellular ion concentrations is crucial for understanding oxidative stress-related disease pathogenesis and developing effective interventions. Herein, a multichannel electrochemical sensor was developed to simultaneously detect dynamic changes in extracellular H + , Ca 2+ , K + , and Na + in HepG2 cells within an ALD cell model. This sensor was fabricated based on patterned laser-induced graphite electrodes modified with H + -sensitive polyaniline and Ca 2+ /K + /Na + -selective membranes. Evaluation in buffered solution systems confirmed that the sensor possessed high sensitivity, excellent anti-interference capability, along with good selectivity, reversibility, and stability in detecting all four target ions. When used to monitor extracellular ion dynamics during ethanol-induced oxidative stress and therapeutic processes in HepG2 cells, it revealed the relationship between ethanol-induced extracellular acidification, K + efflux, intracellular Ca 2+ overload, and oxidative stress. It also demonstrated that ion disorders were significantly alleviated by nutritional intervention with fucoxanthin and its targeted derivatives. This sensor provides an efficient tool for studying ion homeostasis imbalance mechanisms in oxidative stress-related disease and holds potential applications in cell metabolism monitoring, as well as the fabrication and application of real-time multi-ion sensors.

Nature communications • 2025

Bio-denitrification is vital in wastewater treatment plants (WWTPs), yet its integration with naturally abundant thermal energy remains unexplored. Here, we introduce a biohybrid-based pyroelectric bio-denitrification (BHPD) process that harnesses thermoelectric energy from ambient temperature fluctuations. By integrating Thiobacillus denitrificans with tungsten disulfide (WS 2 ), we develop a biohybrid system that achieves complete denitrification over three 5-day cycles under 5 °C temperature fluctuations. WS 2 either precipitates on the cellular surface or is internalized by cells, generating pyroelectric charges that serve as reducing equivalents to drive bio-denitrification. In real wastewater, the BHPD process enhances nitrate removal by up to 8.09-fold under natural temperature fluctuations compared to stable-temperature conditions. Life-cycle assessment demonstrates that the BHPD process has significantly lower environmental impacts than the conventional anaerobic-anoxic-oxic process, and cost analysis confirms its economic feasibility. Our findings highlight the potential of the pyroelectric effect in enhancing bio-denitrification, offering valuable insights for a paradigm shift in WWTPs.

Current microbiology • 2025

The study investigates adaptations of photovoltaic solar panel isolates and their applications. Exiguobacterium aurantiacum (KKOHNGU1) was extracted from a PV solar panel in Patan, Gujarat, India. The objective was to synthesize and characterize silver nanoparticles (AgNPs) using E. aurantiacum (KKOHNGU1) to evaluate their potential in environmental remediation, anticancer, and antibacterial activities. MALDI-TOF analysis identified secondary metabolites as stabilizing and reducing agents. AgNPs were characterized using UV-visible spectroscopy (peak at 425 nm), X-ray diffraction (peaks at 27.6°, 32.12°, and 46.06°), Fourier transform infrared spectroscopy field emission scanning electron microscopy and energy-dispersive spectroscopy, shows spherical crystalline AgNPs with a mean size (121.44 nm). AgNPs (15 mg/mL) showed antibacterial activities, especially against S. aureus, with a 17.5 mm zone of inhibition MIC (2-32 µg/mL), and MBC (32-150 µg/mL). The MTT assay revealed anticancer activity of AgNPs on the MDA-MB-231 breast cancer cell line with an IC 50 value of 172.96 µg/mL. A comparative study showed both bacteria and AgNPs had high potential for MB dye removal, with bacteria achieving 73.55% removal within 120 h and AgNPs showing 97.54% removal within 10 min. These results indicate E. aurantiacum and AgNPs have potential for environmental remediation, particularly in wastewater treatment.

Nature communications • 2025

The integration of microbial nitrogen (N 2 ) fixation with photochemical processes using inorganic light-absorbing nanomaterials is a burgeoning field in sustainable energy production. Here, we explore the synergistic combination of inorganic semiconductor nanowires (NWs) with whole-cell microorganisms to create an inorganic-bacterial biohybrid system. Specifically, we employ Cu 2 O@TiO 2 NWs with a core/shell structure to harness sunlight and generate photoexcited electrons. Azotobacter vinelandii, serving as a biocatalyst, adsorbs onto these NWs and facilitates the reception of photoexcited electrons, thereby enhancing the efficiency of the photoelectrochemical N 2 fixation reaction (PEC-NRR). The biohybrid system achieves an impressive ammonia (NH 3 ) yield of (1.49 ± 0.05) × 10 -9   mol s -1  cm -2 (5.36 ± 0.18 μmol h -1  cm -2 ). The enhancement in NH 3 synthesis within the Cu 2 O@TiO 2 NWs/A. vinelandii biohybrid is attributed to the increased concentrations of nicotinamide adenine dinucleotide-hydrogen (NADH) and adenosine 5'-triphosphate (ATP), as well as the overexpression of N 2 -fixing genes like nifH and nifD within the nitrogenase enzyme complex. This study underscores the potential of inorganic-bacterial biohybrid systems in solar-chemical conversion, paving the way for more diverse and functional approaches to harnessing solar energy for sustainable chemical production.

Current opinion in biotechnology • 2025

Gas fermentation enables the production of fuels, chemicals, and foods from gaseous carbon sources and could serve as a technology for valorizing carbon that may otherwise be emitted to the atmosphere. In this review, we focus on upstream feedstock considerations: the supply of carbon and the supply of electrical power. Electrical power serves a dual role, providing both process energy and biochemical redox potential (via hydrogen or reduced intermediates). We define gas fermentation as bioprocesses involving gaseous feedstocks metabolized by microbes, distinct from microbial electrosynthesis. Trends in CO 2 point sources and low-carbon electricity systems are analyzed, highlighting opportunities and challenges for future deployment. This review synthesizes current knowledge and identifies key R&D priorities for process integration at industrial scale.

Nature communications • 2026

The circular economy should include CO 2 valorization, which could be achieved via microbial electrosynthesis (MES). In MES, the catholyte supplies all nutrients, yet its composition has been adopted from other biotechnologies, overlooking specific needs of MES. In this Perspective, we examine how catholyte design impacts MES performance at microbial, electrochemical, and process levels. We highlight mismatches in metal availability, electrode interactions, and medium origins. We propose reframing the catholyte as a key design parameter and introduce a decision-making framework for tailored formulation. This strategy has the potential to improve MES performance and serve as model for optimizing media in broader biotechnological applications.

Materials horizons • 2025

The growing demand for sustainable energy and effective wastewater treatment has propelled the advancement of bio-electrochemical systems (BESs), particularly microbial fuel cells (MFCs) and microbial electrolysis cells (MECs). These systems integrate bioelectricity generation with organic and inorganic pollutant degradation, offering a sustainable solution for environmental remediation. However, challenges such as high overpotential, reliance on noble metal electrodes, and inconsistent performance have necessitated innovative improvements. The incorporation of photocatalysis into BESs has led to the development of photo-bio-electrochemical systems (PBESs), including photo-microbial fuel cells (PMFCs) and photo-microbial electrolysis cells (PMECs), which leverage optical energy to enhance efficiency. Carbon-based electrode materials, owing to their high porosity, conductivity, and biocompatibility, have emerged as ideal candidates for improving PBES performance. Advanced carbon nanostructures, such as graphene, carbon nanotubes, and metal-graphitic carbon nitride composites, have demonstrated superior photocatalytic properties, promoting enhanced charge separation, CO 2 reduction, hydrogen production, and wastewater treatment. PBES integrating light-activated semiconductor materials with BESs, further amplify pollutant degradation and energy conversion efficiency. Despite significant progress, optimizing electrode materials and improving charge transport remain key challenges for scalable and cost-effective deployment. This review highlights the latest advancements in carbon-based electrodes for PBESs, detailing their mechanisms, photocatalytic properties, and future prospects in sustainable energy production and environmental remediation. By addressing existing material limitations and exploring novel photocatalytic enhancements, this work aims to contribute to the development of next-generation PBESs, fostering circular economy practices and carbon-neutral energy solutions.

Cheng Xiangzhan

Oxford Research Encyclopedia of Environmental Science • 2025

As an independent modern humanities discipline, aesthetics is an essential part of philosophy. Environmental aesthetics is the application of aesthetic theory in the field of environmental studies. Its research objective is the aesthetic appreciation of all kinds of environments (natural and built) and the various things they contain, and it advocates for a view of the harmonious coexistence between people and the environment. Chinese scholars’ contact with environmental aesthetics began in the 1990s. On the one hand, it has been deeply influenced and inspired by Western scholarship, which has provided important references and resources; on the other hand, it is shaped by its specific historical, social, and cultural context, such as the long tradition of Chinese aesthetic appreciation of environments, the awakening of people’s environmental awareness, their increasing attention to environmental issues in China and around the globe, the concepts of “ecological civilizations” and “Beautiful China” as national policies, and so on. All these have effectively prompted Chinese scholars to excavate and reinterpret traditional Chinese environmental aesthetics, consider its contemporary significance, and construct and develop new perspectives. Chinese environmental aesthetics was officially born in 1993 and has had a development history of 30 years as of 2023. After more than 3 decades of academic accumulation and unremitting effort, Chinese scholars have conducted a comprehensive and systematic study of both Western environmental aesthetics and the history of Chinese environmental aesthetics and have thoroughly explored the basic nature, theoretical framework and ideas, core categories, main theses, relations with neighboring fields, practical paths, and future prospects. In particular, different branches of environmental aesthetics such as urban, agricultural, or rural have been explored, as well as identifying and reflecting on the relationship between environmental aesthetics and other related fields such as environmental ethics, ecological aesthetics, and life aesthetics. Different from Western environmental aesthetics, Chinese environmental aesthetics identifies the research objective as “environment appreciation,” constructs the theoretical system as a framework, and then forms the aesthetic model of “what–how–why–how” and the new three-dimensional aesthetic paradigm of “body–mind–environment.” Chinese scholar Chen Wangheng analyzed the “sense of home” implicit in the concept of “environmental beauty” from the perspective of environmental aesthetics. These are all unique theoretical contributions and theoretical values. More importantly, Chinese environmental aesthetics shoulders the mission of promoting the concept of an “ecological civilization,” and its ideological theme should be expanded from the concept of “beautiful China” to “beautiful world” to actively and proactively engage in academic dialogues with Western environmental aesthetics. It also explores and enriches contemporary ecological wisdom and strives to highlight the creativity and cosmopolitan nature of Chinese environmental aesthetics in international environmental aesthetics.