Microbial fuel cells (MFCs) are a promising technology for the production of electricity whilst cleaning waste. In order to gain a better understanding of the wider range of applications where this technology could be implemented, volatile fatty acid-based waste streams were tested as substrates in a rigorous, 12-unit experimental regime. Fermentation can be performed at acidic, neutral and alkaline pHs, with different concentrations. Polarisation experiments were performed to establish the maximum power point and corresponding external resistance applied. Additionally, assessment of performance stability was measured over 40 h under a fixed working load of 1 k ohm. This study investigated MFC performance under four initial pH values and three VFA concentrations, designed to represent the real conditions an MFC might experience. MFCs at pH levels of 7 and 8.5 maintained or increased performance as anolyte concentration increased. Maximum power was achieved under high concentration at pH 8.5, reaching 283 mu W (10.5 mW/m2). MFC performance was limited at lower concentrations, however clear reduction in performance was witnessed at both medium and high concentrations for the pH extremes 5.5 and 10.

Bioelectrochemical systems (BESs), including biophotovoltaics (BPVs) and plant microbial fuel cells (PMFCs), represent an underexplored sustainable source of electricity. However, their power output is generally limited compared to conventional, non-biological technologies. This study investigates the electrical performance of hybrid systems where a BPV is connected in parallel with a photovoltaic (PV) device, and a PMFC is connected in parallel with a direct current generator (CG). We demonstrate that under specific load conditions, these parallel configurations produce higher power or current outputs than the sum of the individual components operating independently-a phenomenon we define as superadditivity. In the BPV-PV system, power gains reached up to 50% at a given external load, with statistically significant improvements under low external loads. The PMFC-CG system also exhibited a superadditive trend, with a 34% increase in peak current output, though not statistically significant. We propose that the superadditive effect arises from reduced internal resistance and perhaps also metabolic stimulation of the biological components when integrated with physicochemical sources in parallel. These findings provide empirical evidence consistent with prior work and supportive of a superadditivity effect in parallel BES-PV/CG systems and offer promising insights for the development of hybrid renewable energy technologies.

Urban environments need low-input cultivation systems that integrate plants into buildings while improving resource efficiency and circularity. This report presents the technical validation of the first operational Microbial–Hydroponic (Mi-Hy) prototype, known as SPIKA, which combines microbial fuel cells (MFCs), vertical hydroponics, and continuous sensing within an architectural-scale installation. The system was stress-tested for seven months (May–December 2025) in a demanding public setting at the Triennale Milano to evaluate its operational stability and robustness. A vertical hydroponic tower and an MFC stack were operated as parallel subsystems under a low-input, recirculating regime, supporting nine ornamental and aromatic plant species. Continuous sensing and imaging provided a longitudinal phenotypic record, enabling a semi-quantitative assessment of plant performance, including growth, flowering, and visual health. Results show stable physicochemical conditions (mean pH 7.1 ± 0.5; mean EC 510 ± 35 µS cm-1) and consistent plant growth without interruption. Over seven months, the system required 35 water refills (52.5 L) and 12 nutrient additions (190 mL). The 12-module MFC stack exhibited open-circuit voltages of 550–620 mV per module. These findings validate the operational reliability of the Mi-Hy framework and establish a baseline for future prototypes integrating nutrient recovery into hydroponic cultivation, advancing toward a fully coupled circular metabolism.

Global wastewater production exceeds 359 billion m3 annually, of which only 52% is treated, mostly in expensive and resource-consuming processes. Microbial electrochemical technologies (METs) offer a transformative approach to sustainable wastewater management by converting waste into valuable resources such as energy, clean water, and nutrients. They present a viable solution to the United Nations’ Sustainable Development Goal 6 (to ensure access to water and sanitation for all) by enhancing both sanitation and resource recovery. METs, including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs), harness electrogenic microorganisms to oxidize organic matter, generating electric energy or producing energy carriers like hydrogen and methane. METs also enable recovery of nutrients, such as ammonium and phosphates, which are essential for agriculture, thereby closing resource loops in a circular economy. Despite their potential, challenges remain in scaling up METs for widespread application. Pilot-scale MFCs and MECs have demonstrated feasibility, achieving up to 90% chemical oxygen demand removal and producing electric power, methane, or hydrogen from wastewater. However, high capital costs, material limitations, and energy efficiency barriers hinder commercialization. Innovations in electrode design, modular configurations, and integration with existing wastewater treatment processes (e.g., anaerobic digestion, membrane bioreactors, or constructed wetlands) are advancing METs toward higher technology readiness levels (TRLs 4–8). Field applications, like a system for urine-based electricity generation in underserved regions, highlight METs adaptability and societal impact. The transition from laboratory to real-world implementation requires scaling, process integration, and further optimization to reduce costs and improve performance. By aligning with circular economy principles, METs can transform wastewater into a resource, contributing to energy security, environmental sustainability, and global sanitation goals. Future research should focus on scalable designs, economic viability, and interdisciplinary collaboration alongside understanding and optimizing the microbial “black box” to enable METs to transform previously unused wastewater streams into valuable resources with targeted applications.

Microbial fuel cells (MFCs) are a promising technology for renewable energy and environmental remediation. The performance of MFCs is greatly influenced by the binder materials used on the electrodes, which must have good conductivity, stability, and compatibility with microorganisms. Synthetic binders, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyuretane (PU), geopolymer binder, and polyvinyl alcohol (PVOH), are commonly used due to their electrochemical properties but are expensive and not environmentally friendly. In contrast, natural binders, such as chitosan, sucrose, carboxymethylcellulose (CMC), and vegetable oils, provide cost-effective and environmentally friendly alternatives. This review synthesizes findings from various studies, comparing the electrochemical properties, stability, and sustainability of chemical and natural binders. The review identifies key research gaps and suggests future directions to improve the performance of natural binders in MFCs, making them more viable for large-scale applications in terms of cost and environmental impact. Natural binders have the potential to be a sustainable alternative in MFC electrode development.

Electro-bioremediation of wastewater is a novel, nature-based solution towards clean water, based on microbial electrochemical technologies (METs). Electro-bioremediation technologies for wastewater treatment, except enhanced bioremediation results and renewable energy generation, offer an unlocked opportunity for harvesting by-products and using them in other applications. This concept contributes to circularity, sustainability, and environmental compatibility, mitigating the impact of climate change. In addition, wastewater valorization and, thus, water resilience are possible thereby leading to protection of water resources. Compounds and metabolites naturally synthesized by the microorganisms involved in the wastewater electro-assisted biodegradation, can result in the enhancement of both extracellular electron transfer (EET) and bioremediation. Such microbial products are added-value, natural, non-toxic and biodegradable such as biosurfactants (BSFs) and polyhydroxyalkanoates (PHAs). In this chapter, the effect of the presence of BSFs and PHAs in MET during electro-bioremediation, as well as when fed with conventional substrates, are exhaustively evaluated. The significance of BSFs even when they are added exogenously is also examined. The major categories of by-products biosynthesis including organic acids, biopolymers, recovered heavy metals and phenazines such as pyocyanin during electro-bioremediation processes are also discussed. Consequently, a future direction in wastewater electro-bioremediation is proposed.

The ever-increasing pollution on our planet demands the development of clean technologies. Microbial fuel cell (MFC) is one technology with multiple benefits, including, but not limited to, wastewater treatment, bioelectricity generation, heavy metal toxicity reduction, and fertiliser production through catholyte formation. In-situ catholyte production in MFCs requires more research to understand how it can be tailored for biofertiliser and bioelectricity production. This study aims to produce better quality catholyte and observe its correlation with bioelectricity generation using ceramic additives known as biomedia. To evaluate its effect on catholyte electrosynthesis and concomitant production of bioelectricity, a mix of fine-grained ceramic additives was introduced to the anolyte. Over the course of the experiment, it was observed that the synthesis of catholyte in MFCs containing biomedia, was 35 % higher in volume compared to that of the MFCs without biomedia, and the electrical conductivity increased to a maximum of 15.72 mS/cm with pH 11.23 with elements such as aluminium being removed from the wastewater in the anode. The current and power generation were also significantly higher in biomedia-MFCs, which suggests its correlation with better quality catholyte. The novel approach of using low cost ceramic additives to amend anolytewas demonstrated as an effective strategy to enhance catholyte production combined with high electricity generation in MFC.

This position paper presents part of the history of Microbial Fuel Cells (MFCs) development for practical applications. Studies that shaped the MFC concept in the 20th century are highlighted along with the first robotic developments involving MFCs. The paper also gives examples of real-world implementation, learnings from field trials and how these have contributed to the fundamental advancement of the technology. Given the status of global affairs and the significance of energy security, the paper also provides a perspective on the future of the technology and where it may offer a valuable utility.

Efficient human waste management and hygiene maintenance are vital for long-duration space missions. By using bioelectrochemical systems, specifically microbial fuel cells (MFCs) combined with hydroponics, human waste can potentially be converted into a valuable commodity. Recent advancements in MFCs indicate a significant potential for generating electricity (1–2 mW/single MFC/ml of urine) and biofertilisers concurrently from urine and sewage while suppressing human pathogens that may be present. Integrating MFCs with hydroponics opens up the possibility to balance nutrients in human waste while growing vegetables in MFC-powered hydroponic systems, using only a small percentage of synthetic fertilisers, if deemed necessary. This is a concise perspective of the potential of MFCs for nutrient recycling from human waste and vegetable production that could enhance the self-sustainability of a spacecraft or mission.

In this study, a novel composite anode electrode for microbial fuel cells (MFCs) was developed by wrapping a carbon sleeve around the surface of carbon veil. While the carbon veil is widely used due to its biocompatibility and surface area, its poor mechanical strength limits long-term operation. The novelty of the study lies in reinforcing the flexible, non-woven carbon veil with a mechanically robust and tubular carbon sleeve layer without compromising performance. This composite electrode (carbon veil + carbon sleeve) improved mechanical integrity and in addition, facilitated better biofilm development. Over a 5 week operation, the composite anode achieved a maximum power output of 527.7 μW, a 3-fold increase compared to using the carbon veil alone (175.5 μW). SEM analysis confirms biofilm improvement in the combined electrodes compared to the control. FTIR analysis confirmed changes in surface functional groups post-operation, suggesting enhanced biofilm-electrode interactions. This work demonstrates a simple yet effective reinforcement strategy that significantly enhances MFC anode durability and power performance.

Conventional techniques for treating wastewater consume significant energy and depending on effectiveness, may result in secondary contamination. In this regard, the microbial fuel cell (MFC) technology has shown much promise as a revolutionary wastewater treatment + energy generation hybrid. This is due to the unique ability of electroactive organisms to generate direct electricity, recovering electrons from the breakdown and consumption of organic compounds in wastewater. This article critically assesses the current development of MFC technology, particularly in the last two years, focussing on the technology's economic and environmental feasibility. Even though there is a significant body of literature on MFCs with continuously increasing performance levels, the technology has not yet got fully commercialised to become part of urban planning or energy policy; this implies a lack of government consideration as a result of the absence of industrial scale research. The article presents the case for MFCs from a technology readiness level and life cycle assessment perspectives and explains why it is still premature to draw conclusions based on these two metrics.

This comprehensive review explores the transformative role of remote sensing technologies in the detection and monitoring of water pollution. Remote sensing provides dynamic, large-scale, and cost-effective solutions for continuous assessment of water quality. The review covers the application of remote sensing for detecting a range of pollutants, including chemical contaminants, physical parameters, and biological pollutants. The review systematically analyzed 132 studies selected from the Web of Science database using the keywords “remote sensing” and “water pollution,” covering publications from the 1990s to December 2023. The analysis highlights the use of multispectral and hyperspectral imaging, machine learning algorithms, and statistical models for precise pollutant detection and quantification.Key findings demonstrate the efficacy of remote sensing in providing timely and detailed information on water quality, which is essential for environmental monitoring and management. However, several challenges persist, including limitations in the spatial and temporal resolution of satellite sensors, the complexity of water body optical properties, and the need for advanced data processing algorithms. Future research should address these challenges by focusing on enhancing sensor technology, developing sophisticated algorithms for data analysis, and integrating remote sensing with in-situ measurements to achieve more comprehensive water quality monitoring. This review underscores the significant advancements in remote sensing technologies and their crucial role in sustainable water resource management and environmental protection. It emphasizes the need for ongoing innovation and interdisciplinary collaboration to further enhance our understanding and management of water pollution.

Correction for ‘Nanofiber applications in microbial fuel cells for enhanced energy generation: a mini review’ by Fatma Yalcinkaya et al., RSC Adv., 2024, 14, 9122–9136, DOI: https://doi.org/10.1039/D4RA00674G.

Microbial fuel cells (MFCs) represent simple devices that harness the metabolic activities of microorganisms to produce electrical energy from diverse sources such as organic waste and sustainable biomass.

In the present study, the potential of Pseudomonas citronellolis 620C strain was evaluated, for the first time, to generate electricity in a standard, double chamber microbial fuel cell (MFC), with oily wastewater (OW) being the fuel at 43.625 mg/L initial chemical oxygen demand (COD). Both electrochemical and physicochemical results suggested that this P. citronellolis strain utilized efficiently the OW substrate and generated electricity in the MFC setup reaching 0.05 mW/m2 maximum power. COD removal was remarkable reaching 83.6 ± 0.1

The application of microbial fuel cells in sanitation has demonstrated feasibility in supplying electricity and providing safety in underserved communities, especially at toilet blocks. Two different designs of urine fed MFC cascades, ceramic MFCs (c-MFC) and self-stratifying MFCs (s-MFC), have been employed in large-scale feasibility studies. As part of a pre-commercialisation approach, this study verified the resilience of each design when a commercial disinfectant was introduced into the system. Five different conditions, varying in concentrations (24.2 mM-604.5 mM) and the total volume (50-500 mL) of sodium hypochlorite disinfectant introduced, were tested. Upon adding the disinfectant, both types of MFC-cascades exhibited rapid power drops with response times lower than 5 min in all tested conditions, followed by relatively swift recovery times of up to 250 min. The volume of disinfectant introduced had a greater impact on power output than its concentration or dose. Comparing the two designs, the c-MFC demonstrated a much larger voltage drop, up to 0 mV, and shorter recovery time compared to the s-MFC under most test conditions, mainly attributed to the presence (c-MFC) or absence (s-MFC) of a membrane. Overall, both types of MFCs exhibited strong resilience to sodium hypochlorite additions, thereby highlighting the commercial potential of the technology towards safe off-grid sanitation.

In its comprehensive sense, a technology goes beyond the hardware or system to include associated skills and knowledge. Whilst this definition has been acknowledged across the literature, there is a gap in practices reflected during technology transfer processes. This article aims to investigate measures that can be taken by technology providers and recipients to effectively incorporate knowledge and skills sharing during a technology transfer. Conceptual frameworks were developed and used to inform empirical research. The case study of the PEEPOWER technology is carried out to consolidate theory with practice. The PEEPOWER technology is illustrated on a ‘techberg’ showing all elements of the technology beyond the hardware. An insight into the level of effectiveness of the PEEPOWER transfer to Kisoro, Nairobi and Durban is obtained through a qualitative analysis of interview responses, by looking at the extent of knowledge sharing and the absorptive capacity of the technology recipient. The main recommendations are to (1) adopt a knowledge exchange approach as opposed to a unidirectional knowledge transfer from the technology provider to the technology recipient, (2) establish good relationships with local partners and develop a good understanding of the local context and (3) manage expectations about innovations and ensure intellectual property protection during knowledge exchange.