Search Results (52)

Microbial fuel cell (MFC) is a novel and environmentally friendly technology for wastewater treatment and pollutant resource utilization. Although advances have been made in various aspects including electrode materials and synthetic biology approaches, the overall performance of MFC still requires improvement, with mass transfer efficiency and structural stability of biofilms emerging as key bottlenecks constraining their practical applications. This study investigated the regulation of substrate type and electrode potential during bioanode culture to optimize biofilm structure and enhance MFC performance. Results demonstrated that bioanodes cultured with glucose at −0.3 V formed vertically ordered biofilms that exhibited significant advantages in mass transfer characteristics, electrocatalytic activity, and structural stability. Under these culture conditions, enriched fermentative microorganisms facilitated the construction of porous biofilm scaffolds, while the electric field generated by the −0.3 V potential further induced vertical orientation and ordered arrangement of the biofilm. The superior mass transfer characteristics enabled the inner, middle, and outer layers of the biofilm to maintain high microbial activity (>50%), thereby maximizing the catalytic activity of electroactive microorganisms in each layer and enhancing biofilm structural stability. This study proposes a bioanode culture strategy centered on biofilm structural optimization, providing new theoretical foundations and technical pathways for achieving long-term stable and efficient MFC operation. Full article

This work investigated the use of microbial fuel cells (MFCs) for the degradation of polyethylene terephthalate (PET) and the simultaneous generation of electricity. The study implemented two separate single-chamber MFCs, one with a co-culture of Ideonella sakaiensis and Geobacter sulfurreducens (I.S-G.S) and the other with Ideonella sakaiensis and activated sludge (I.S-AS). The effectiveness of microplastic (MP) degradation was assessed based on the electroactivity of the anodic biofilm, the reduction in particle size, and the decrease in PET mass. Both systems achieved a significant reduction in MP size and mass, with the I.S-AS system notably surpassing the I.S-G.S in terms of efficiency and electricity generation. The I.S-AS system achieved a 30% mass reduction and 80% size reduction, along with a peak voltage of 222 mV. The study concludes that MFCs, particularly with the activated sludge co-culture, offer a viable and more environmentally friendly alternative for MP degradation and energy recovery. These findings suggest a promising direction for improving waste management practices and advancing the capabilities of bio-electrochemical systems in addressing plastic pollution. Further research is recommended to optimize the operational conditions and to test a broader range of MP sizes for enhanced degradation efficacy. Full article

This study discussed the influence of acetate and sodium chloride concentration on monitoring 2,4-dichlorophenol(2,4-DCP) by electroactive bacteria. The performance of the reactor was represented by power density, and the electrochemical activity was represented by redox capacity. At the same time, micro-electrodes were used to detect the redox potential between biofilms, and the changes in extracellular polymers and microbial community structure under different conditions were also explored. With acetate concentration of 1 g/L and sodium chloride concentration of 0.0125 g/L, the electroactive microorganisms were more sensitive to toxic substances and responded fast. The biofilm also evenly covered on the surface of the carrier, which aided in the diffusion of substances. Although the maximum power density monotonically increased with acetate concentration, high concentration of substrate may mask the inhibitory effect and affect the judgment of inhibitory results. The content of protein and polysaccharide increased monotonically with sodium chloride concentration. However, more polysaccharides would lead to high resistance to electron transfer. Compared to sodium chloride, the microbial content was more affected by acetate. The electroactive microorganisms had strong adaptability to salinity. In practical application, it is conducive to increase the sensitivity of MFCs to reasonably reduce the concentration of acetic acid and sodium chloride. Full article

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

Bio-nanocomposite films were prepared using chitosan, gelatin, and varying concentrations (0, 0.5, 1.0, 2.0, and 5.0 wt%) of titanium dioxide (TiO₂) nanoparticles in acetic acid via a casting method. The incorporation of TiO₂ nanoparticles into the bio-chitosan matrix enhanced ultraviolet (UV) absorption and improved the films’ physical, mechanical, and electrical properties. Additionally, the TiO₂-loaded films exhibited antimicrobial activity, contributing to the extended preservation of packaged products by inhibiting microbial growth. Notably, the bio-nanocomposite films containing 1.0 wt% TiO₂ exhibited an electroactive response, bending under relatively low electric field strength (250 V/mm), whereas the control film without TiO₂ required higher field strength (550 V/mm) to achieve bending. This indicates potential applications in electroactive actuators requiring precise movement control. Among the tested concentrations, films containing 0.5 wt% and 1.0 wt% TiO₂ (Formulas 7 and 8) demonstrated optimal performance. These films presented a visually appealing appearance with no tear marks, low bulk density (0.91 ± 0.04 and 0.85 ± 0.18 g/cm³), a satisfactory electromechanical response at 250 V/m (17.85 ± 2.58 and 61.48 ± 6.97), low shrinkage percentages (59.95 ± 3.59 and 54.17 ± 9.28), high dielectric constant (1.80 ± 0.07 and 8.10 ± 0.73), and superior UV absorption compared with pure bio-chitosan films, without and with gelatin (Formulas 1 and 6). Full article

Microbial fuel cells (MFCs) generate electricity through the microbial oxidation of organic waste. However, the inherent electrochemical performance of carbon felt (CF) electrodes is relatively poor and requires enhancement. In this study, nickel oxide (NiO) was successfully loaded onto CF to improve its electrode performance, thereby enhancing the electricity generation capacity of MFCs during the degradation of treated wastewater. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy diffusion spectrometer (EDS) analyses confirmed the successful deposition of NiO on the CF surface. The modification enhanced both the conductivity and capacitance of the electrode and increased the number of microbial attachment sites on the carbon fiber filaments. The prepared CF–NiO electrode was employed as the anode in an MFC, and its electrochemical and energy storage performance were evaluated. The maximum power density of the MFC with the CF–NiO anode reached 0.22 W/m², compared to 0.08 W/m² for the unmodified CF anode. Under the C1000-D1000 condition, the charge storage capacity and total charge output of the CF–NiO anode were 1290.03 C/m² and 14,150.03 C/m², respectively, which are significantly higher than the 452.9 C/m² and 6742.67 C/m² observed for the CF anode. These results indicate notable improvements in both power generation and energy storage performance. High-throughput gene sequencing of the anodic biofilm following MFC acclimation revealed that the CF–NiO anode surface hosted a higher proportion of electroactive bacteria. This suggests that the NiO modification enhances the biodegradation of organic matter and improves electricity generation efficiency. Full article

This study explores the feasibility of producing biohydrogen from winery wastewater using a dual-chamber microbial electrolysis cell (MEC). A mixed microbial consortium pre-adapted to heavy-metal environments and enriched with Geobacter sulfurreducens was anaerobically cultivated from diverse waste streams. Over 5000 h of development, the MEC system was progressively adapted to winery wastewater, enabling long-term electrochemical stability and high organic matter degradation. Upon winery wastewater addition (5% v/v), the system achieved a sustained hydrogen production rate of (0.7 ± 0.3) L H₂ L⁻¹ d⁻¹, with an average current density of (60 ± 4) A m⁻³, and COD removal efficiency exceeding 55%, highlighting the system’s resilience despite the presence of inhibitory compounds. Coulombic efficiency and cathodic hydrogen recovery reached (75 ± 4)% and (87 ± 5)%, respectively. Electrochemical impedance spectroscopy provided mechanistic insight into charge transfer and biofilm development, correlating resistive parameters with biological adaptation. These findings demonstrate the potential of MECs to simultaneously treat agro-industrial wastewaters and recover energy in the form of hydrogen, supporting circular resource management strategies. Full article

A novel three-dimensional porous biocarbon electrode with exceptional biocompatibility was synthesized via a facile approach using pumpkin as the precursor. The obtained pumpkin-derived biocarbon features a highly porous architecture and serves as an efficient biocarbon electrode (denoted as PBE) in a microbial fuel cell (MFC). This PBE could form robust biofilms to facilitate the adhesion of electroactive bacteria. When used in the treatment of real wastewater, the assembled PBE-MFC achieves a remarkable power density of 231 mW/m², much higher than the control (carbon brush—MFC, 164 mW/m²) under the identical conditions. This result may be attributed to the upregulation of flagellar assembly pathways and bacterial secretion systems in the electroactive bacteria (e.g., Hydrogenophaga, Desulfovibrio, Thiobacillus, Rhodanobacter) at the anode of the PBE-MFC. The increased abundance of nitrifying bacteria (e.g., Hyphomicrobium, Sulfurimonas, Aequorivita) and organic matter-degrading bacteria (e.g., Lysobacter) in the PBE-MFC also contributed to its exceptional wastewater treatment efficiency. With its outstanding biocompatibility, cost-effectiveness, environmental sustainability, and ease of fabrication, the PBE-MFC displays great potential for application in the field of high-performance and economic wastewater treatment. Full article

To address the limitations of conventional antibacterial therapies, we developed an injectable, conductive polyurethane-based composite gel system for sustained root canal disinfection. This gel incorporates piezoelectric nanoparticles (n-BaTiO₃) and conductive segments (aniline trimer, AT) within a polyurethane matrix, which synergistically interact with a static antimicrobial agent (n-ZnO) to achieve dynamic, mechano-responsive antibacterial activity. Under cyclic compression (simulating mastication), the piezoelectric gels exhibited enhanced electroactivity via the mechano-electric coupling effect, generating 2-fold higher voltage and a 1.8–1.9× increase in current compared to non-piezoelectric controls. The dynamic electroactivity of the gels enabled superior long-term performance, achieving 92–97% biofilm eradication, significantly higher than the static n-ZnO-only gel (88%). XPS and UV-vis spectroscopy analyses confirmed mechano-electrochemically amplified reactive oxygen species (ROS) generation, which contributed to improved biofilm disruption. The ISO-compliant gel provides durable, load-responsive disinfection while maintaining good biocompatibility, offering a promising solution to prevent post-treatment reinfection. Full article

Microbial biosensors are bioanalytical devices that can measure the toxicity of pollutants or detect specific substances. This is the greatest advantage of microbial biosensors which use whole cells of microorganisms as powerful tools for measuring integral parameters of environmental pollution. This review explores the core principles of microbial biosensors including biofuel devices, emphasizing their capacity to evaluate biochemical oxygen demand (BOD), toxicity, heavy metals, surfactants, phenols, pesticides, inorganic pollutants, and microbiological contamination. However, practical challenges, such as sensitivity to environmental factors like pH, salinity, and the presence of competing substances, continue to hinder their broader application and long-term stability. The performance of these biosensors is closely tied to both technological advancement and the scientific understanding of biological systems, which influence data interpretation and device optimization. The review further examines cutting-edge developments, including the integration of electroactive biofilms with nanomaterials, molecular biology techniques, and artificial intelligence, all of which significantly enhance biosensor functionality and analytical accuracy. Commercial implementations and improvement strategies are also discussed, providing a comprehensive overview of the state-of-the-art in this field. Overall, this work consolidates recent progress and identifies both the potential and limitations of microbial biosensors, offering valuable insights into their future development for environmental monitoring. Full article

In a plant microbial fuel cell (P-MFC), the plant provides the fuel in the form of exudates secreted by the roots, which are oxidised by electroactive bacteria. The immature plant is hampered by low energy yields. Several factors may explain this situation, including the low open-circuit voltage of the plant cell. This is a function of the development of the biofilm formed by the electroactive bacteria on the surface of the anode, in relation to the availability of the exudates produced by the roots. In order to exploit the fertilising role of biochars, a plant cell was developed from C. citratus and grown in a medium to which 5% by mass of coconut shell biochar had been added. Its effect was studied as well as the distance between the electrodes. The potential of Cymbopogon citratus was also evaluated. Three samples without biochar, with inter-electrode distances of 2, 5 and 7 cm, respectively, identified as SCS2, SCS5 and SCS7, and three with the addition of 5 % biochar, with the same inter-electrode distance values, identified as S2, S5 and S7, were prepared. Open-circuit voltage (OCV) measurements were taken at 6 a.m., 1 p.m. and 8 p.m. The results showed that all the samples had high open-circuit voltage values at 1 p.m. Samples containing 5% biochar had open-circuit voltages increased by 16 %, 8.94% and 5.78%, respectively, for inter-electrode distances of 2, 5 and 7 cm compared with those containing no biochar. Furthermore, the highest open-circuit voltage values were obtained for all samples with C. citratus at an inter-electrode distance of 5 cm. The maximum power output of the PMFC with C. citratus in this study was 75.8 mW/m², which is much higher than the power output of PMFCs in recent studies. Full article

A microbial fuel cell (MFC) is a bio-electrochemical system that utilizes electroactive microorganisms to generate electricity. These microorganisms, which convert the energy stored in substrates such as wastewater into electricity, grow on the anode. To ensure biocompatibility, anodes are typically made from carbon-based materials. Therefore, a carbon-based material (by-product of coconut processing) was selected for testing in this study. The anode was prepared by bonding activated coconut carbon with carbon paint on a glass electrode. The aim of this study was to analyze the feasibility of using an electrode prepared in this manner as a surface layer on the anode of an MFC. The performance of an electrode coated only with carbon paint was also evaluated. These two electrodes were compared with a carbon felt electrode, which is commonly used as an anode material in MFCs. In this research, the MFC was fed with a by-product of yeast production, namely a molasses decoction from yeast processing. Measurements were conducted in a standard two-chamber glass MFC with a glass membrane separating the chambers. During the experiment, parameters such as start-up time, cell voltage during MFC start-up, output cell voltage, and power density curves were analyzed. The carbon paint-coated electrode with the activated coconut carbon additive demonstrated operating parameters similar to those of the carbon felt electrode. The results indicate that it is possible to produce electrodes (on a base of by-product of coconut processing) for MFCs using a painting method; however, to achieve a performance comparable to carbon felt, the addition of activated coconut carbon is necessary. This study demonstrates the feasibility of forming a biocompatible layer on various surfaces. Incorporating activated coconut carbon does not complicate the anode fabrication process, as fine ACC grains can be directly applied to the wet carbon paint layer. Additionally, the use of carbon paint as a conductive layer for the active anode in MFCs offers versatility in designing electrodes of various shapes, enabling them to be coated with a suitable active and conductive layer to promote biofilm formation. Moreover, the findings of this study confirm that waste-derived materials can be effectively utilized as electrode components in MFC anodes. The results validate the chosen research approach and emphasize the potential for further investigations in this field, contributing to the development of cost-efficient electrodes derived from by-products for MFC applications. Full article

The reverse polarity biocathode culture (RPBC) is a technology for the rapid preparation of biocathodes, which quickly enrich electroactive bacteria (EAB) in the microbial fuel cell (MFC) anode and then transform the electrode function from bioanode to biocathode by reversing bioelectrode polarity. However, the mechanism of RPBC is still unclear, and methods to regulate performance and ensure the long-term stability of cultured biocathodes have not been established. This study investigated the correlation between electrogenic bacteria and the target reducing EAB, from two aspects: energy supply and the formation of a composite biofilm. The results showed that electrogenic bacteria provided energy for the reducing EAB through interspecies electron transfer. This process could be regulated by changing the electrode potential and substrate concentration to obtain an optimized biocathode. In addition, the RPBC forms a composite biofilm of electrogenic bacteria and reducing EAB, which significantly improves the enrichment efficiency and the amount of reducing EAB (compared with a direct biocathode culture, respectively, shortening the enrichment time by 80%, increasing the electroactivity by 12.4 times, and increasing the nitrate degradation rate by 4.85 times). This study provides insights into regulating the performance and maintaining the long-term stability of RPBC-cultured biocathodes. Full article

Microbial electrochemical cells (MxCs) offer a sustainable approach for wastewater treatment and energy recovery by harnessing the electroactive properties of microorganisms. This study explores the enrichment of Geobacter species on anode biofilms in single-(S-MxCs) and double-chambered (D-MxCs) MxCs, using domestic wastewater without an external anode potential. Stable current densities were achieved within 10 days for S-MxCs (9.52 ± 0.8 A/m²) and 14 days for D-MxCs (4.28 ± 0.9 A/m²), with S-MxCs showing a superior electrochemical performance. Hydrogen production rates were higher in D-MxCs (14.93 ± 0.66 mmol H₂/L/day) compared to S-MxCs (9.46 ± 0.8 mmol H₂/L/day), with cumulative production rates of 12.9 ± 1.3 mmol H₂/g COD and 6.48 ± 1.4 mmol H₂/g COD, respectively. Cyclic voltammetry confirmed enhanced bioelectrocatalytic activity in S-MxCs, while SEM imaging showed denser biofilms on S-MxC anodes. The novelty of this study lies in its demonstration of efficient biofilm development and microbial community resilience under non-potentialized conditions, providing insights that advance the practical application of MxCs in environmental biotechnology. Full article

Bioelectrochemical processes are emerging as one of the most efficient and sustainable technologies for wastewater treatment. Their application for industrial wastewater treatment is still low due to the high toxicity and difficulty of biological treatment for industrial effluents. This is especially relevant in pharmaceutical industries, where different solvents, active pharma ingredients (APIs), extreme pH, and salinity usually form a lethal cocktail for the bacterial community in bioreactors. This work evaluates the impact of the anode architecture on the detoxification performance and analyzes, for the first time, the profile of some key bioremediation enzymes (catalase and esterase) and reactive oxygen species (ROS) during the operation of microbial electrochemical cells treating real pharmaceutical wastewater. Our results show the existence of oxidative stress and loss of cell viability in planktonic cells, while the electrogenic bacteria that form the biofilm maintain their biochemical machinery intact, as observed in the bioelectrochemical response. Monitorization of electrical current flowing in the bioelectrochemical system showed how electroactive biofilm, after a short adaptation period, started to degrade the pharma effluent. The electroactive biofilms are responsible for the detoxification of this type of industrial wastewater. Full article