Lincoln Mtemeri, Scott Calabrese Barton, David P. Hickey

ECS Meeting Abstracts • 2024

Cell-free bioelectrocatalysis has drawn significant research attention as a Green approach for producing commodity and fine chemicals. Enzymatic bioelectrocatalysis utilizes electrodes to drive challenging enzymatic redox reactions, such as CO 2 reduction and selective oxidation of lignocellulosic biomass to generate value-added products. For many oxidoreductases, the redox cofactor is buried within the insulating protein matrix and, thus, inaccessible to the heterogeneous electrode surface. In such cases, electrochemically active small molecules, called redox mediators, have been proven effective in enabling efficient electron transfer by acting as electron shuttles between the electrode and enzyme cofactor. To this end, redox-active hydrogels have become a critical component of many bioelectrocatalysis applications as a way to create an efficient enzyme/electrode interface. Polymers containing covalently attached redox mediators are cross-linked in the presence of a desired oxidoreductase onto the surface of an electrode to form a bioelectrocatalytic hydrogel. This strategy simultaneously immobilizes enzymes at the electrode interface – thereby simplifying product purification and mitigating mass transfer limitations – and improving electron transfer kinetics necessary for electrochemically regenerating the redox cofactor. Despite the success and broad application of redox polymers in enzymatic bioelectrocatalysis, critical interactions between polymer-bound mediators and redox enzymes remain poorly understood, thereby adding significant complications to the design of novel redox polymers. Moreover, there are notable (and seemingly contradictory) discrepancies between the activity of commonly used enzymes, such as glucose oxidase, with freely solvated mediators compared to their polymer-bound counterparts. We have employed a combination of electroanalytical techniques with an array of computational tools (including density function theory (DFT), static docking simulations, and molecular dynamics simulations) to provide new insights into the role that both protein structure and redox polymer composition play in designing efficient bioelectrochemical interfaces. Specifically, we compare the interactions of a commonly used naphthoquinone-modified linear poly(ethylenimine) hydrogel with two structurally analogous enzymes, GOx and FAD-dependent glucose dehydrogenase, that lead to divergent electrocatalytic activity despite both being equally active towards a comparable freely diffusing mediator.

Kevin Beaver, Shelley D. Minteer

ECS Meeting Abstracts • 2021

The development of microbial fuel cells (MFCs) for wastewater treatment has recently gained significant attention in the bioremediation and renewable energy industries. Bacteria can be integrated into the anodes of MFCs to oxidize organic wastes, simultaneously producing electrical current and decontaminating wastewater. The photoheterotrophic purple bacterium Rhodobacter capsulatus has demonstrated photo-catalyzed electron transfer to carbon electrodes via exogenous quinone redox mediators, and tolerance to high salinity, opening opportunities for solar-powered MFC systems for treatment of saline wastewater. While the consumption of malate by R. capsulatus has been electrochemically analyzed previously, in this project, alternative target carbon sources were examined in order to improve electrochemical performance of these R. capsulatus systems. A combination of electrochemical techniques and biological assays were used to evaluate the relative viability of malate, lactate, succinate and propionate as oxidizable fuels. Specifically, cyclic voltammetry and amperometry data demonstrated that R. capsulatus generates distinctive bio-photocurrent densities depending on the fuel metabolized. Bioanodes with immobilized R. capsulatus cells oxidizing lactate (9.49 ± 1.89 µA cm -2 ) as the fuel yielded the greatest mediated bio-photocurrent densities compared to the other fuels, while those metabolizing propionate (1.33 ± 0.18 µA cm -2 ) generated the smallest current densities. In tandem with electrochemistry methods, growth curve assays and RNA sequencing were performed to further delve into the biological effects of altering the carbon source.

David E Cliffel, Christopher Stachurski, John Williams

ECS Meeting Abstracts • 2022

Photosystem I (PSI) is one of the primary macromolecular machines that drive photosynthesis in green plants and cyanobacteria. Extracted PSI has been employed successfully as a macromolecular photosensitizer within a host of low-cost electrochemical and solid-state photovoltaic architectures. This presentation will also explore our group’s recent efforts to integrate PSI with advanced nanomaterials, including carbon nanotubes, carbon quantum dots, and conducting polymers polyaniline (PANI), polypyrrole, polyviologens, and poly(3,4-ethylenedioxythiophene). These composite assemblies enhance charge shuttling processes from individual proteins within multilayer assemblies—greatly reducing charge transfer resistances and improving overall efficiency of photocells. The group has reported two new prototype solid-state devices in which PSI or PSI/PANI is sandwiched between energetically appropriate electrodes. The group has also succeeded in stabilizing PSI films via crosslinking to create “wet” photoelectrochemical cells with greater performance and longevity. Finally, our current work is aimed at building new prototypes using PSI in solid state interfaces for scalable solar energy conversion. Finally, the incorporation of PSI into conducting polymer frameworks holds promise for improved conductivity and orientational control in the photoactive layers in these devices.

Juliette Pelletier, Raphaël Trouillon

ECS Meeting Abstracts • 2024

Context- Paper is an innovative material for cell culture due to its biocompatibility, its inert chemical properties and its low-cost. Paper is already used in many biomedical applications such as immunoassays and, more recently, as affordable electrochemical sensors. In this context, tuning the properties of paper devices can achieve better, more efficient and user-friendly assays for biomedical applications. Here, and by modifying the electrochemical properties of paper electrochemical devices, it is possible to create electrodes that can detect neurotransmitters, a critical type of biomolecules involved in neuronal communication. Dopamine is a neurotransmitter involved in reward and addiction and a molecule of considerable scientific interest. Dopamine is secreted in the brain by dopaminergic neurons. However, the fine chemical mechanisms of neuron networks are still obscure. Being able to spatially measure dopamine secretion, in response to activation of precise neuronal regions in a unique system, can lead to a better understanding of neuronal dynamics, as well as their response to drug alterations. Proposing a research model describing neuronal chemical function in a network will therefore help shining light on their mechanisms and testing new neuropharmacological solutions. Developing new tools for the analytical electrochemistry of the brain will make quantitative neuro-analysis more accessible, thus paving the way for a better understanding of the chemical mechanisms of the brain. Tuning paper electrode for neurochemical analysis- Conductive inks, i.e. conductive polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and carbon nanotubes (CNT) suspensions, were used to improve the detection of dopamine at paper-based electrodes. The physical and chemical properties of different preparations and mixtures of inks were considered. Solvent secondary doping, a common technique for PEDOT-PSS based electrode, was used to improve the electrical properties of the electrodes. Ferrocyanide electroanalysis was used to benchmark 10 different electrode preparations, revealing that combining CNT and PEDOT-PSS improves the electroactivity of the surface of the sensor. Interestingly, it was found that CNT has a doping effect on PEDOT-PSS, leading to improved electrochemical properties. Finally, these electrodes were tested for dopamine detection. It was found that combining PEDOT-PSS and CNT in the surface layer of ink deposited on the paper electrode allows for lower capacitance, higher anodic current as well as better fouling resistance. Figure 1 presents a CV voltammogram for Dopamine obtained with a paper electrode. Overall, this strategy improves the sensitivity of the assay. Growing neurons on paper- Paper-based devices can also be used for cell culture. Cell on paper constructs are 3D cell culture models that are more suitable to study cell in a biomimetic 3D environment, thus better recapitulating their functions and biology. By carefully modifying the surface of the paper devices, it is possible to adjust their biocompatible properties to ameliorate the survival rate of cell culture on paper. This opens the possibility to achieve neuronal cell culture on paper. We will present different paper preparations compatible with murine dopaminergic maintenance. The neurons were maintained alive for several days of culture. We were able to effectively observe and study neurons in a 3D paper environment and quantify the growth of their processes. Figure 1 : Electrochemical detection of Dopamine for 20 cycles. Working electrode is a paper electrode with PEDOT:PSS and CNT conductive inks, shown on the right, scale is 1 cm. The reference electrode is an Ag/AgCl electrode, and the counter electrode is a platinum electrode. Scan rate is 0.02 Vs -1 . Figure 1

Savannah Stuart‐Dahl, Edith Martinez‐Guerra, Bahareh Kokabian et al.

Engineering in Life Sciences • 2020

Abstract In this research, low strength synthetic wastewaters with chemical oxygen demand less than 300 mg L −1 were treated at different concentrations in a bioelectrochemical desalination process. A process optimization model was utilized to study the performance of the photosynthetic bioelectrochemical desalination process. The variables include substrate (chemical oxygen demand) concentration, total dissolved solids, and microalgae biomass concentration in the cathode chamber. Relationships between the chemical oxygen demand concentration, microalgae, and salt concentrations were evaluated. Power densities and potential energy benefits from microalgal biomass growth were discussed. The results from this study demonstrated the reliability and reproducibility of the photosynthetic microbial desalination process performance followed by a response surface methodology optimization. This study also confirms the suitability of bioelectrochemical desalination process for treating low substrate wastewaters such as agricultural wastewaters, anaerobic digester effluents, and septic tank effluents for net energy production and water desalination.

Anna Joicy, Young-Chae Song, Jun Li et al.

Energies • 2020

The effect of electrostatic fields on the bioelectrochemical removal of ammonium and nitrite from nitrogen-rich wastewater was investigated at strengths ranging from 0.2 to 0.67 V/cm in bioelectrochemical anaerobic batch reactors. The electrostatic field enriched the bulk solution with electroactive bacteria, including ammonium oxidizing exoelectrogens (AOE) and denitritating electrotrophs (DNE). The electroactive bacteria removed ammonium and nitrite simultaneously with alkalinity consumption through biological direct interspecies electron transfer (DIET) in the bulk solution. However, the total nitrogen (ammonium and nitrite) removal rate increased from 106.1 to 166.3 mg N/g volatile suspended solids (VSS).d as the electrostatic field strength increased from 0.2 to 0.67 V/cm. In the cyclic voltammogram, the redox peaks corresponding to the activities of AOE and DNE increased as the strength of the electrostatic field increased. Based on the microbial taxonomic profiling, the dominant genera involved in the bioelectrochemical nitrogen removal were identified as Pseudomonas, Petrimonas, DQ677001_g, Thiopseudomonas, Lentimicrobium, and Porphyromonadaceae_uc. This suggests that the electrostatic field of 0.67 V/cm significantly improves the bioelectrochemical nitrogen removal by enriching the bulk solution with AOE and DNE and promoting the biological DIET between them.

Refka Askri, Benjamin Erable, Luc Etcheverry et al.

Frontiers in Bioengineering and Biotechnology • 2020

The textile and clothing industry is the first manufacture sector in Tunisia in terms of employment and number of enterprises. It generates large volumes of textile dyeing wastewater (TDWW) containing high concentrations of saline, alkaline, and recalcitrant pollutants that could fuel tenacious and resilient electrochemically active microorganisms in bioanodes of bioelectrochemical systems. In this study, a designed hybrid bacterial halothermotolerant bioanode incorporating indigenous and exogenous bacteria from both hypersaline sediment of Chott El Djerid (HSCE) and TDWW is proposed for simultaneous treatment of real TDWW and anodic current generation under high salinity. For the proposed halothermotolerant bioanodes, electrical current production, chemical oxygen demand (COD) removal efficiency, and bacterial community dynamics were monitored. All the experiments of halothermotolerant bioanode formation have been conducted on 6 cm 2 carbon felt electrodes polarized at −0.1 V/SCE and inoculated with 80% of TDWW and 20% of HSCE for 17 days at 45°C. A reproducible current production of about 12.5 ± 0.2 A/m 2 and a total of 91 ± 3% of COD removal efficiency were experimentally validated. Metagenomic analysis demonstrated significant differences in bacterial diversity mainly at species level between anodic biofilms incorporating allochthonous and autochthonous bacteria and anodic biofilm containing only autochthonous bacteria as a control. Therefore, we concluded that these results provide for the first time a new noteworthy alternative for achieving treatment and recover energy, in the form of a high electric current, from real saline TDWW.

Hongda Pan, Qing Feng, Yong Zhao et al.

Fermentation • 2023

The effect of bioelectrochemical anaerobic digestion (BEAD) on the methanogenic performance of brewery wastewater at different organic loading rates (OLRs) was investigated and compared to conventional anaerobic digestion. A continuous BEAD reactor was used to treat brewery wastewater at different OLRs of 2, 4, 8, 16, and 20 g COD/L.d. The experimental results showed that the methane production was gradually increased from 0.48 L/L.d at an OLR of 2 g COD/L.d to 5.64 L/L.d at an OLR of 20 g COD/L.d. The methane production of the BEAD system was significantly higher than that of the conventional anaerobic reactor, indicating that BEAD has a better treatment effect for brewery wastewater. The performance of the conventional anaerobic reactor was significantly reduced especially at an OLR of 16 g COD/L.d, while the BEAD system could withstand a higher OLR. Bioelectrochemical systems provide a completely new platform for the anaerobic treatment of brewery wastewater and greatly improve the operation of anaerobic processes.

Jiaxin Liu, Xue Yan, Qiang Ding et al.

Sustainability • 2025

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.

Yeray Asensio, María Llorente, Alejandro Sánchez-Gómez et al.

Frontiers in Microbiology • 2021

The capacity of electroactive bacteria to exchange electrons with electroconductive materials has been explored during the last two decades as part of a new field called electromicrobiology. Such microbial metabolism has been validated to enhance the bioremediation of wastewater pollutants. In contrast with standard materials like rods, plates, or felts made of graphite, we have explored the use of an alternative strategy using a fluid-like electrode as part of a microbial electrochemical fluidized bed reactor (ME-FBR). After verifying the low adsorption capacity of the pharmaceutical pollutants on the fluid-bed electrode [7.92 ± 0.05% carbamazepine (CBZ) and 9.42 ± 0.09% sulfamethoxazole (SMX)], our system showed a remarkable capacity to outperform classical solutions for removing pollutants (more than 80%) from the pharmaceutical industry like CBZ and SMX. Moreover, the ME-FBR performance revealed the impact of selecting an anode potential by efficiently removing both pollutants at + 200 mV. The high TOC removal efficiency also demonstrated that electrostimulation of electroactive bacteria in ME-FBR could overcome the expected microbial inhibition due to the presence of CBZ and SMX. Cyclic voltammograms revealed the successful electron transfer between microbial biofilm and the fluid-like electrode bed throughout the polarization tests. Finally, Vibrio fischeri -based ecotoxicity showed a 70% reduction after treating wastewater with a fluid-like anode (+ 400 mV), revealing the promising performance of this bioelectrochemical approach.

O. D. Akinwumi, S. E., Agarry, M. O. Aremu et al.

LAUTECH Journal of Engineering and Technology • 2024

Pharmaceutical wastewater (PWW) as an industrial wastewater presents a potential hazard to natural water systems. This wastewater contains organic matter, which is toxic to the various life forms of the system. PWW is one of the major health problems nowadays, not only for aquatic life but also for human beings and the environment. There are several methods such as filtration, advanced oxidation, coagulation and biological membranes been used for the treatment of PWW, however, all of these methods are limited in their results and applications. In this present study, Microbial Fuel Cells (MFCs) represent a new method for treating wastewater, generating electricity, and reducing COD simultaneously. A novel H-type MFC connected with a graphite electrode has been designed for bioelectricity generation, COD reduction as well as PWW treatment. The treatment of PWW showed adequate bioelectricity generation such as Voltage, Current, and Power, of about 775 mV, 0.421 mA, and 583.70 mW at 100 Ω respectively. The percentage of the COD removed ranged from 95.2-96.7% and 12-34% at the different process variables. This study established bioelectricity generation and bio-treatment of PWW.

Pavlos K. Pandis, Marina Georgala, Paraskevi Nanou et al.

Key Engineering Materials • 2023

Microbial Fuel Cells (MFCs) are electrochemical devices that exploit microbes for wastewater treatment with simultaneous power production. Concerning reactor design, electrode materials and operation modes, great achievements have been reported with an emphasis on developing anode materials to improve overall MFC performance. Anode materials (carbon cloth, carbon veil, carbon sponges) and their properties such as biocompatibility, electrical conductivity, surface area and efficient transport of waste play a very important role in power generation in MFCs. Despite their low cost, they present structural-based disadvantages eg. Fragility, and low conductivity issues. Additive manufacturing of Fused Deposition Modelling (FDM) due to its tailoring properties, has employed various polymer-based materials such as Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) for manufacturing applications. In addition, carbon-based composites and hybrid materials eg. electrically conductive PLA and ABS have already been fabricated and are commercially available to exploit good electrical conductivity and structural rigidness. In this research, FDM was used to fabricate custom-sized electrodes made of a laboratory-produced electrically conductive ABS filament. A parametric study of conductivity and biocompatibility properties of these electrodes in correlation to 3D printer parameters was investigated and reported. Furthermore, treatment with a combination of thermal, mechanical, and chemical procedures was performed to improve the crucial parameters of anodes for MFCs.

Reneta Boukoureshtlieva, Toma Stankulov, Anton Momchilov

Ecological Engineering and Environment Protection • 2021

In the past 20 years Microbial fuel cells (MFCs) have been extensively studied regarding the possibility of transforming organic waste directly into electricity. There are significant differences between MFCs and conventional low temperature Fuel Cells (FCs), which make MFCs attractive: biotic catalyst at the anode; the anodic fuel is complex organic waste; MFCs operate under mild reaction conditions (neutral pH, temperature and pressure), close to ambient levels as optimum. Like chemical fuel cells, MFCs are composed of anode and cathode. Oxygen is an ideal electron acceptor for MFCs because of its high redox potential, availability, and sustainability. However, the Oxygen Reduction Reaction (ORR) is kinetically sluggish, resulting in a large proportion of potential loss. Also, working conditions are quite different because of the type of complex media in which MFCs operate. In order to overcome these limitations, catalysts are often used to lower the overpotentials and accelerate the kinetics of the oxygen reduction reaction. One of the main challenges is the development of efficient and stable cathode catalysts for MFCs. By far, Pt and Pt-based catalysts (PGMs) have been extensively used, due to their catalytic efficiency in gas-diffusion electrodes. But the high cost and low durability have significantly lowered their utilization in MFCs. A variety of non-precious metal catalysts have been developed for MFC applications including carbon-based catalysts, carbon supported composite catalysts, Me-based catalysts and biocatalysts. It is supposed that the ORR catalyst used for wastewater treatment in MFCs is simple to synthesize, cost-effective, durable after long-term operation in wastewater, tolerant to poisoning and able to restore catalytic activity after cleaning. In this regard carbon-based catalyst may be the most promising candidate for practical applications. This study reviews different carbon-based ORR catalysts for MFC applications for wastewater treatment and energy recovery.

Ying Chao

MATEC Web of Conferences • 2025

The integration of microbial fuel cells (MFCs) with biomass waste utilization presents a promising pathway for simultaneous energy recovery and environmental remediation. MFCs generate electricity by harnessing the metabolic activity of electroactive microorganisms, which oxidize organic substrates and transfer electrons to an external circuit. This review investigates the operational principles of MFCs, core system components, and their capacity to convert diverse biomass-derived substrates—including agricultural residues, food waste, and industrial wastewater—into electrical energy. Pretreatment techniques such as mechanical reduction and irradiation are discussed for improving substrate bioavailability and enhancing power density. The technical and economic feasibility of MFCs is evaluated, highlighting current limitations such as low energy output, material costs, and scale-up challenges. Additionally, the role of MFCs in carbon fixation and circular bioeconomy models is examined, demonstrating their potential to reduce greenhouse gas emissions while recovering valuable resources. Despite unresolved engineering and microbial constraints, ongoing advances in materials science, system architecture, and microbial engineering are expected to enhance the scalability and efficiency of MFC-based waste-to-energy platforms. This review underscores the importance of further interdisciplinary research to realize the full potential of MFCs in sustainable energy and waste management systems.

Yu-Chen Liu, Yu-Hsuan Hung, Shih-Fu Liu et al.

Sustainable Energy & Fuels • 2020

The MFCs with N-MWCNT@GONR and MWCNT@GONR anodes exhibits high power densities up to 3444 mW m −2 and 3291 mW m −2 .

Leena R, Arya Sethu Madhavan, Lineesh M Kunjappan

ECS Meeting Abstracts • 2021

Melatonin(N-acetyl-5-methoxy tryptamine) is a paracrine hormone secreted by pineal gland in the brain. This endogenous hormone has the ability to maintain the body circadian rhythm. 1 3,4-dihydroxy-L-phenylalanine (L-Dopa) is the intermediate precursor of the Neurotransmitter dopamine. L-dopa, as one of catecholamines, is widely used as a source of dopamine in the treatment of Parkinson’s disease and epilepsy. 2 Here, we report a sensor based on Platinum electrode modified with hydrothermally synthesized RGO and spinel nanoferrate for the simultaneous determination of L-Dopa and Melatonin. Graphene oxide (GO)is a graphene derived material with oxygen containing functional groups. Graphene is a material with honey comb like structure of carbon atoms having sp 2 bonding character. It exhibits high electrical conductivity, thermal conductivity and mechanical strength. GO containing functional groups like –OH, -COOH etc., acts as the site for the nucleation of metal oxide nanoparticles. It improves direct electron transfer between the electrode and the redox species by accelerating the electron transfer and enlarging the effective surface area. 3 GO was synthesized by modified Hummers method. Chemically converted graphene RGO has been prepared by various reduction methods such as chemical, microwave, electrochemical, thermal, solvothermal/hydrothermal, by reducing its oxygen content. 4 Green synthetic pathway of hydrothermal method was adopted for RGO synthesis to avoid hazardous chemical species and vigorous reaction conditions. Spinel ferrate like Copper Cobalt ferrate (CuCoFe 2 O 4 ) was synthesized by sol-gel method and RGO/Spinel nanocomposite was prepared by physical mixing. 5 The synthesized materials were characterized using various techniques like FTIR, XRD, FESEM etc. The electro catalytic activity of RGO/Spinel nanocomposite anchored platinum electrode for the simultaneous determination of melatonin and L-Dopa was studied using several voltammetric techniques. Bare platinum electrode was able to sense melatonin and L-Dopa both individually, but not simultaneously. Compared to RGO modified Platinum electrode, RGO-Spinel ferrate/Pt electrode exhibited good response in terms of lower potential of electrooxidation of L-Dopa and Melatonin with enhanced catalytic current with a peak separation of 0.48V. This enhancement in electrochemical performance is due to the increase in surface area as well as conductivity of the electrode upon modification with RGO-spinel nanocomposite which act as an excellent electrochemical oxidant for L-Dopa and melatonin. References: Levent, A. J. Diam. Relat. Mater. 2012 , 21, 114-119 Yan, X.; Pan, D.; Wang, H.; Bo, X.; Guo, L. J. Electroanal. Chem. 2011 , 663, 36-42 Pei, S.; Zhao, J.; Du, J.; Ren, W.; Cheng, H. J. Carbon. 2010 , 48, 4466-4474 Luo, D.; Zhang, G.; Liu, J.; Sun, X. J. Phys. Chem. C. 2011 , 115, 11327-11335 Elkholy, A. E.; Heakal, F. E.; Allam, K. A. J. RSC Adv. 2017 , 7, 51888

Leena R, Arya Sethu M

ECS Meeting Abstracts • 2020

Melatonin(N-acetyl-5-methoxy tryptamine) is a paracrine hormone secreted by pineal gland in the brain. This endogenous hormone has the ability to maintain the body circadian rhythm. 1 3,4-dihydroxy-L-phenylalanine (L-Dopa) is the intermediate precursor of the neurotransmitter dopamine. L-dopa,as one of catecholamines, is widely used as a source of dopamine in the treatment of Parkinson’s disease and epilepsy. 2 Here, we report a sensor based on Platinum electrode modified with hydrothermally synthesised RGO and spinel nano ferrate for the simultaneous determination of L-Dopa and Melatonin. Graphene oxide (GO)is a graphene derived material with oxygen containing functional groups. Graphene is a material with honey comb like structure of carbon atoms having sp 2 bonding character. It exhibits high electrical conductivity, thermal conductivity and mechanical strength.GO containing functional groups like –OH, -COOH etc., acts as the site for the nucleation of metal oxide nano particles.It improves direct electron transfer between the electrode and the redox species by accelerating the electron transfer and enlarging the effective surface area. 3 GO was synthesized by modified Hummers method. Reduced graphene oxide (RGO) has been prepared by various reduction methods such as chemical, microwave, electrochemical, thermal, solvothermal, hydrothermal etc by reducing its oxygen content. 4 We employed a green synthetic pathway of hydrothermal method for RGO synthesis to avoid hazardous chemical species and vigorous reaction conditions. Copper Cobalt ferrate (CuCoFe 2 O 4 ) which is a spinel nanocomposite was synthesised by sol-gel method and RGO/Spinel nanocomposite was prepared by physical mixing. 5 The prepared RGO spinel nanocomposite was characterized by using various techniques like FTIR, XRD, SEM-EDAX etc.The electrocatalytic activity of RGO/Spinel nanocomposite anchored platinum electrode for the simultaneous determination of melatonin and L-Dopa was studied using several voltammetric techniques. Bare platinum electrode was able to sense melatonin and L-Dopa both individually, but not simultaneously. Compared to RGO modified Platinum electrode, RGO-Spinel ferrate/Pt electrode exhibited good response in terms of lower potential of electrooxidation of L-Dopa and melatonin with enhanced catalytic current with a peak separation of 0.48V. The simultaneous square wave voltammetric determination of L-Dopa and melatonin on RGO modified Platinum electrode and RGO-Spinel ferrate/Pt electrode are shown in Fig. 1. This enhancement in electrochemical performance is due to the increase in surface area as well as conductivity of the platinum electrode upon modification of RGO with spinel nanocomposite which act as an excellent electrochemical oxidant for L-Dopa and melatonin. References: 1. Levent, A., Diam. Relat. Mater., 2012 , 21, 114-119. 2. Yan, X.; Pan, D.; Wang, H.; Bo, X.; Guo, L., J. Electroanal. Chem., 2011 , 663, 36-42. 3. Pei, S.; Zhao, J.; Du, J.; Ren, W.; Cheng, H., Carbon, 2010 , 48, 4466-4474. 4. Luo, D.; Zhang, G.; Liu, J.; Sun, X., J. Phys. Chem. C, 2011 , 115, 11327-11335. 5. Elkholy, A. E.; Heakal, F. E.; Allam, K. A., RSC Adv., 2017 , 7, 51888. Figure 1

Myoung Eun Lee, Yongtae Ahn, Seung Gu Shin et al.

Energies • 2022

Anaerobic digestion (AD) can produce renewable energy and reduce carbon emissions, but the energy conversion efficiency is still limited in some waste streams. This study tested the effect of applied voltage removal for microbial electrolysis cells (MECs) treating primary sewage sludge. Two MECs were operated in parallel: a MEC-0.3 V with an applied voltage of 0.3 V and a MEC-OCV with open circuit voltage. Both reactors were inoculated with seed sludge originating from a MEC at 0.3 V applied voltage, and three batch cycles were operated for 36 d. The methane production of the MEC-OCV was 3759 mL/L in the first cycle and 2759 mL/L in the second cycle, which was similar (105% and 103%, respectively) to that of the MEC-0.3 V. However, in the third cycle, the methane production of the MEC-OCV (1762 mL/L) was 38.8% lower than that of the MEC-0.3 V (4545 mL/L). The methane contents in the biogas were 68.6–74.2% from the MEC-OCV, comparable to those from the MEC-0.3 V (66.6–71.1%). These results indicate that not only the MEC-0.3V but also the MEC-OCV outperformed AD in terms of methane yield and productivity, and the promotion using MEC-derived inoculum persisted equally with the MEC-OCV for two batch cycles after removing the applied voltage. Therefore, a MEC operation with cycled power supply may be beneficial in reducing the electric energy usage and improving the biogas production performance, compared to conventional AD.

Jerry Huayang Tang

IOP Conference Series: Earth and Environmental Science • 2021

Abstract Microbial electrolysis cells (MECs) represent a renewable hydrogen production technology that offers the possibility of converting wastewater to hydrogen through a bioelectrochemical process. Particularly, the MEC substrate has a significant effect on the performance of MECs, and in this review, the performances of over 30 substrates examined since 2015 are summarized and compared. It was evident that popular MEC substrates include dark fermentation effluents, pyrolysis products, and raw wastewaters. Additionally, the different MEC substrates investigated yielded different MEC performances, indicating that further studies are required before MECs can become a mature technology for up-scale applications.

E. Chorbadzhiyska, I. Bardarov, Y. Hubenova et al.

Bulgarian Chemical Communications • 2019

Microbial electrolysis cell (MEC) is an ecologically clean and innovative technology for hydrogen production. The development of cost-effective cathodes with high catalytic activity for hydrogen evolution reaction (HER) in nearneutral electrolytes is the most critical challenge for the practical application of MEC technology. In this study, graphite electrodes, functionalized with non-noble metal oxides, were produced and after electrochemical pre-treatment investigated as potential cathodes for MEC. The morphology of the developed materials was analyzed by scanning electron microscopy (SEM). Their electrochemical performance in neutral phosphate buffer solution (PBS) was explored by means of linear sweep voltammetry (LSV) and chronoamperometry (CA). The results from both methods show that all modified electrodes exhibit higher electrocatalytic activity towards HER than that of bare graphite, which is a prerequisite for further evaluation of these materials as cathodes in real MEC.

Marie Abadikhah, Miguel de Celis Rodriguez, Frank Persson et al.

Frontiers in Microbiology • 2022

In single-chamber microbial electrolysis cells (MECs), organic compounds are oxidized at the anode, liberating electrons that are used for hydrogen evolution at the cathode. Microbial communities on the anode and cathode surfaces and in the bulk liquid determine the function of the MEC. The communities are complex, and their assembly processes are poorly understood. We investigated MEC performance and community composition in nine MECs with a carbon cloth anode and a cathode of carbon nanoparticles, titanium, or stainless steel. Differences in lag time during the startup of replicate MECs suggested that the initial colonization by electrogenic bacteria was stochastic. A network analysis revealed negative correlations between different putatively electrogenic Deltaproteobacteria on the anode. Proximity to the conductive anode surface is important for electrogens, so the competition for space could explain the observed negative correlations. The cathode communities were dominated by hydrogen-utilizing taxa such as Methanobacterium and had a much lower proportion of negative correlations than the anodes. This could be explained by the diffusion of hydrogen throughout the cathode biofilms, reducing the need to compete for space.

Aliya Temirbekova, Zhanar Tekebayeva, Aslan Temirkhanov et al.

Biology • 2023

Natural resources are in short supply, and the ecosystem is being damaged as a result of the overuse of fossil fuels. The creation of novel technology is greatly desired for investigating renewable and sustainable energy sources. Microorganisms have received a lot of interest recently for their potential to transform organic waste into sustainable energy and high-value goods. New exoelectrogens that can transmit electrons to electrodes and remove specific wastewater contaminants are expected to be studied. In this study, we examined three distinct samples (as determined by chemical oxygen demand and pH) that can be used as anolytes to generate power in single-chamber and double-chamber microbial fuel cells using graphite electrodes. Wastewater from poultry farms was studied as an exoelectrogenic anolyte for microbial fuel cell power generation. The study examined 10 different bacterial strains, numbered A1 through A10. Due to their highly anticipated capacity to metabolize organic/inorganic chemicals, the diverse range of microorganisms found in poultry wastewater inspired us to investigate the viability of generating electricity using microbial fuel cells. From the investigated bacterial strains, the highest voltage outputs were produced by strains A1 (Lysinibacillus sphaericus) and A2 (Bacillus cereus), respectively, at 402 mV and 350 mV. Among the 10 different bacterial strains, strain A6 generated the least amount of electricity, measuring 35.03 mV. Furthermore, a maximum power density of 16.16 1.02 mW/m2 was achieved by the microbial fuel cell using strain A1, significantly outperforming the microbial fuel cell using a sterile medium. The strain A2 showed significant current and power densities of 35 1.12 mA/m2 and 12.25 1.05 mW/m2, respectively. Moreover, in the two representative strains, chemical oxygen demand removal and Coulombic efficiency were noted. Samples from the effluent anode chamber were taken in order to gauge the effectiveness of chemical oxygen demand removal. Wastewater had an initial chemical oxygen demand content of 350 mg/L on average. Strains A1 and A2 decomposed 94.28% and 91.71%, respectively, of the organic substrate, according to the chemical oxygen demand removal efficiency values after 72 h. Strains A1 and A2 had electron donor oxidation efficiencies for 72 h of 54.1% and 60.67%, respectively. The Coulombic efficiency increased as the chemical oxygen demand decreased, indicating greater microbial electroactivity. With representative strains A1 and A2, Coulombic efficiencies of 10% and 3.5%, respectively, were obtained in the microbial fuel cell. The findings of this study greatly advance the field as a viable source of power technology for alternative energy in the future, which is important given the depletion of natural resources.

Weilu Yang, Hexing Han, Minghua Zhou et al.

RSC Advances • 2015

A novel continuous flow electrosorption driven by microbial fuel cells (MFCs) was developed for the first time to remove tetracycline, the second most commonly used antibiotic, from synthetic wastewater.

Vajihe Yousefi, Davod Mohebbi-Kalhori, Abdolreza Samimi et al.

International Journal of Hydrogen Energy • 2016

Remisha S R, Reshmi R, Sanmathi K R

International Journal of Advanced Research in Science, Communication and Technology • 2023

The contamination of industrial wastewater with heavy metals poses a severe environmental and public health concern. Traditional methods of heavy metal removal often prove costly and environmentally unsustainable. In this context, microbial strategies have emerged as a promising and eco-friendly approach for effective heavy metal remediation from industrial wastewater. Microorganisms, including bacteria, fungi, and algae, have developed various mechanisms to withstand and sequester heavy metals from their surroundings. This review explores the diverse microbial strategies employed in heavy metal removal, encompassing biosorption, bioaccumulation, bioprecipitation, and bioleaching. These strategies exploit microbial cell surfaces, extracellular polymeric substances, and intracellular compartments to immobilize, transform, or release heavy metals. Moreover, recent advancements in genetic engineering and biotechnology have enabled the development of tailored microbial strains with enhanced metal-removal capabilities. The application of these engineered microbes, as well as naturally occurring strains, in bioremediation processes is discussed. This review also delves into the factors influencing microbial metal removal efficiency, such as pH, temperature, metal concentration, and co-existing contaminants. Additionally, the potential drawbacks and limitations of microbial strategies, including biomass disposal and long-term performance, are addressed. As heavy metal pollution continues to be a pressing global issue, understanding and harnessing microbial strategies for heavy metal removal from industrial wastewater holds significant promise for sustainable and cost-effective remediation practices. Integrating microbial processes into existing treatment methods can offer innovative solutions to mitigate the environmental impact of heavy metal contamination, thereby safeguarding ecosystems and public health

Dong-Mei Piao, Young-Chae Song, Dong-Hoon Kim

Energies • 2018

This study demonstrated the enhancement of biogenic coal conversion to methane in a bioelectrochemical anaerobic reactor with polarized electrodes. The electrode with 1.0 V polarization increased the methane yield of coal to 52.5 mL/g lignite, which is the highest value reported to the best of our knowledge. The electrode with 2.0 V polarization shortened the adaptation time for methane production from coal, although the methane yield was slightly less than that of the 1.0 V electrode. After the methane production from coal in the bioelectrochemical reactor, the hydrolysis product, soluble organic residue, was still above 3600 mg chemical oxygen demand (COD)/L. The hydrolysis product has a substrate inhibition effect and inhibited further conversion of coal to methane. The dilution of the hydrolysis product mitigates the substrate inhibition to methane production, and a 5.7-fold dilution inhibited the methane conversion rate by 50%. An additional methane yield of 55.3 mL/g lignite was obtained when the hydrolysis product was diluted 10-fold in the anaerobic toxicity test. The biogenic conversion of coal to methane was significantly improved by the polarization of the electrode in the bioelectrochemical anaerobic reactor, and the dilution of the hydrolysis product further improved the methane yield.

Brittany Newell, Jose Garcia, Gary Krutz

Actuators • 2018

Dielectric electroactive polymer materials represent a distinct group of smart materials that are capable of converting between electrical and mechanical energy. This research focuses on the modeling and testing of an industrial grade fluoropolymer material for its feasibility as a dielectric elastomer electroactive polymer. Through this process, a novel chemical pre-strain method was tested, along with a one-step process for application of pre-strain and addition of an elastomer conductive layer. Modeled and experimental actuators produced approximately 1 mm displacements with 0.625 W of electrical power. The displacement of the actuators was characterized, and the effects of multiple parameters were modeled and analyzed.

Erin M. Gaffney, Olja Simoska, Shelley D. Minteer

Biosensors • 2021

Halophilic bacteria are remarkable organisms that have evolved strategies to survive in high saline concentrations. These bacteria offer many advances for microbial-based biotechnologies and are commonly used for industrial processes such as compatible solute synthesis, biofuel production, and other microbial processes that occur in high saline environments. Using halophilic bacteria in electrochemical systems offers enhanced stability and applications in extreme environments where common electroactive microorganisms would not survive. Incorporating halophilic bacteria into microbial fuel cells has become of particular interest for renewable energy generation and self-powered biosensing since many wastewaters can contain fluctuating and high saline concentrations. In this perspective, we highlight the evolutionary mechanisms of halophilic microorganisms, review their application in microbial electrochemical sensing, and offer future perspectives and directions in using halophilic electroactive microorganisms for high saline biosensing.

Arkadiy I. Garber, Kenneth H. Nealson, Nancy Merino

Frontiers in Microbiology • 2024

Multi-heme cytochromes (MHCs), together with accessory proteins like porins and periplasmic cytochromes, enable microbes to transport electrons between the cytoplasmic membrane and extracellular substrates (e.g., minerals, electrodes, other cells). Extracellular electron transfer (EET) has been described in multiple systems; yet, the broad phylogenetic and mechanistic diversity of these pathways is less clear. One commonality in EET-capable systems is the involvement of MHCs, in the form of porin-cytochrome complexes, pili-like cytochrome polymers, and lipid-anchored extracellular cytochromes. Here, we put forth MHCscan—a software tool for identifying MHCs and identifying potential EET capability. Using MHCscan, we scanned ~60,000 bacterial and 2,000 archaeal assemblies, and identify a diversity of MHCs, many of which represent enzymes with no known function, and many found within organisms not previously known to be electroactive. In total, our scan identified ~1,400 unique enzymes, each encoding more than 10 heme-binding motifs. In our analysis, we also find evidence for modularity and flexibility in MHC-dependent EET pathways, and suggest that MHCs may be far more common than previously recognized, with many facets yet to be discovered. We present MHCscan as a lightweight and user-friendly software tool that is freely available: https://github.com/Arkadiy-Garber/MHCscan .

Shan-Wei Li, Guo-Ping Sheng, Yuan-Yuan Cheng et al.

Scientific Reports • 2016

Abstract Although the capacity for electroactive bacteria to convert environmental metallic minerals and organic pollutants is well known, the role of the redox properties of microbial extracellular polymeric substances (EPS) in this process is poorly understood. In this work, the redox properties of EPS from two widely present electroactive bacterial strains ( Shewanella oneidensis and Pseudomonas putida ) were explored. Electrochemical analysis demonstrates that the EPS extracted from the two strains exhibited redox properties. Spectroelectrochemical and protein electrophoresis analyses indicate that the extracted EPS from S. oneidensis and P. putida contained heme-binding proteins, which were identified as the possible redox components in the EPS. The results of heme-mediated behavior of EPS may provide an insight into the important roles of EPS in electroactive bacteria to maximize their redox capability for biogeochemical cycling, environmental bioremediation and wastewater treatment.

Robin Bonné, Koen Wouters, Jamie J. M. Lustermans et al.

Frontiers in Microbiology • 2022

The global production of unrecycled electronic waste is extensively growing each year, urging the search for alternatives in biodegradable electronic materials. Electroactive bacteria and their nanowires have emerged as a new route toward electronic biological materials (e-biologics). Recent studies on electron transport in cable bacteria—filamentous, multicellular electroactive bacteria—showed centimeter long electron transport in an organized conductive fiber structure with high conductivities and remarkable intrinsic electrical properties. In this work we give a brief overview of the recent advances in biodegradable electronics with a focus on the use of biomaterials and electroactive bacteria, and with special attention for cable bacteria. We investigate the potential of cable bacteria in this field, as we compare the intrinsic electrical properties of cable bacteria to organic and inorganic electronic materials. Based on their intrinsic electrical properties, we show cable bacteria filaments to have great potential as for instance interconnects and transistor channels in a new generation of bioelectronics. Together with other biomaterials and electroactive bacteria they open electrifying routes toward a new generation of biodegradable electronics.

Min-Hua Cui, Dan Cui, Hyung-Sool Lee et al.

Scientific Reports • 2016

Abstract In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m 3 ·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment.

Patricia M. Olmos Moya, Silvia Gutiérrez Granados, Fethi Bedioui et al.

Electroanalysis • 2020

Abstract An amperometric biosensor for the sensitive detection of superoxide was designed utilizing a drop‐coating approach for immobilizing the superoxide dismutase enzyme on Pt electrode modified with a thin layer of poly (3,4‐ethylenedioxythiophene) (PEDOT). The layer electrodeposited on Pt was characterized by cyclic voltammetry and atomic force microscopy (AFM). Then, drop‐coating procedure was chosen for the immobilization of superoxide dismutase (SOD), which was incorporated at the electrode surface using a solution containing SOD, glutaraldehyde and bovine serum albumin (optimized composition: SOD 0.1 % – BSA 2 % – GA 2.5 % .) This simple procedure allows forming a reproducible enzymatic biocomposite layer that allows optimal sensitivity and limit of detection for superoxide sensing. The synergistic effect integrates an effective conductivity and permselectivity attributed to the PEDOT layer, as well as the specificity and selectivity of SOD for the detection of superoxide. A high sensitivity (0.82±0.01 μA/μM) and a low detection limit of 11 nM were obtained, as well as good selectivity against main interfering biological compounds such as uric acid and ascorbic acid. Our results suggest that the biosensor could be used for the detection and quantification of in vitro and in vivo .

Andreea Madalina Pandele, Corina Andronescu, Adi Ghebaur et al.

Materials • 2018

A high number of studies support the use of mesoporous silica nanoparticles (MSN) as carriers for drug delivery systems due to its high biocompatibility both in vitro and in vivo, its large surface area, controlled pore size and, more than this, its good excretion capacity from the body. In this work we attempt to establish the optimal encapsulation parameters of benzalkonium chloride (BZC) into MSN and further study its drug release. The influence of different parameters towards the drug loading in MSN such as pH, contact time and temperature were considered. The adsorption mechanism of the drug has been determined by using the equilibrium data. The modification process was proved using several methods such as Fourier transform-infrared (FT-IR), ultraviolet-visible (UV-VIS), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). Since MSN shows a lower drug release amount due to the agglomeration tendency, in order to increase MSN dispersion and drug release amount from MSN, two common biocompatible and biodegradable polymers were used as polymer matrix in which the MSN-BZC can be dispersed. The drug release profile of the MSN-BZC and of the synthesized hybrid materials were studied both in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Polymer-MSN-BZC hybrid materials exhibit a higher drug release percent than the pure MSN-BZC when a higher dispersion is achieved. The dispersion of MSN into the hybrid materials was pointed out in scanning electron microscope (SEM) images. The release mechanism was determined using four mathematic models including first-order, Higuchi, Korsmeyer–Peppas and Weibull.

Miroslav Kvíčala, Michaela Štamborská, Jaromír Drápala

Applied Mechanics and Materials • 2015

This paper is dedicated to the development and optimization of the porous titanium materials suitable for biomedical usage in traumatology. Main aim of the presented research activities is focused on preparation of biocompatible titanium based materials with controlled porosity. It was found that titanium specimens with total porosity approximately 40 % revealed mechanical properties very similar to those of human cortical bone. Two-layer specimens with controlled porosity were prepared and tested by electron microscopy for post-sintering cracks. All tested specimens with controlled porosity were cracks free. Future works will include preparation of geometrically more complicated shapes, machining and in vitro cells proliferation testing.

Mohammad Luqman, Saeed Alqaed, Fahad Awjah Almehmadi et al.

Journal of Electroanalytical Chemistry • 2024

Yanuar Rohmat Aji Pradana, Firhan Ahmad Fanani, Aminnudin Aminnudin et al.

Key Engineering Materials • 2020

Subsequent processing through machining for biocompatible Zr-based BMG previously developed is needed in order to enlarge the material application, especially for medical devices. In this study the performance of CuCr tool on EDM process was investigated to cut biocompatible Zr-based BMG having low machinability nature. The experiment utilized volume loss technique to measure the TWR and consecutive SEM observation to reveal the tool wear mechanism of selected tool samples. The tool wear behavior was strongly characterized by the combination of discharge current and pulse-on time, where the larger TWR obtained by higher current and shorter pulse-on time. By SEM analysis, the irregular-shaped surface morphology with the presence of debris was observed on the tool wear region resulted by high discharge energy process. Additionally, the larger crater size, microvoids and numerous debris particles were also appeared on BMG workpiece surface machined using higher discharge energy.

Hindatu Yusuf, M. Suffian M. Annuar, Syed Mohammad Daniel Syed Mohamed et al.

Chemical Engineering Communications • 2019

Mohan Qin, Ibrahim M. Abu-Reesh, Zhen He

Water Research • 2016

Osmotic microbial fuel cells (OsMFCs) take advantages of synergy between forward osmosis (FO) and microbial fuel cells (MFCs) to accomplish wastewater treatment, current generation, and high-quality water extraction. As an FO based technology, OsMFCs also encounter reverse salt flux (RSF) that is the backward transport of salt ions across the FO membrane into the treated wastewater. This RSF can reduce water flux, contaminate the treated wastewater, and increase the operational expense, and thus must be properly addressed before any possible applications. In this study, we aimed to understand the effects of current generation and electrolyte pH on RSF in an OsMFC. It was found that electricity generation could greatly inhibit RSF, which decreased from 16.3 ± 2.8 to 3.9 ± 0.7 gMH when the total Coulomb production increased from 0 to 311 C. The OsMFC exhibited 45.9 ± 28.4% lower RSF at the catholyte pH of 3 than that at pH 11 when 40 Ω external resistance was connected. The amount of sodium ions transported across the FO membrane was 18.3-40.7% more than that of chloride ions. Ion transport was accomplished via diffusion and electrically-driven migration, and the theoretical analysis showed that the inhibited electrically-driven migration should be responsible for the reduced RSF. These findings are potentially important to control and reduce RSF in OsMFCs or other osmotic-driven processes.

Harsha Nagar, N. Badhrachalam, V.V. Basava Rao et al.

Materials Chemistry and Physics • 2019