Hanna Frühauf, Markus Stöckl, Dirk Holtmann

• 2020

<p>Mechanisms of electron transfer vary greatly within the diverse group of electroactive microorganisms and so does the need to attach to the electrode surface, e.g. by forming a biofilm.</p> <p>Electrochemical impedance spectroscopy (EIS) and confocal laser scanning microscopy (CLSM) are well established methods to monitor cell attachment to an electrode surface and have therefore been combined in a flow cell as a screening system. The flow cell, equipped with a transparent indium tin oxide working electrode (ITO WE), allows monitoring of attachment processes in real time with minimal needs for additional biofilm preparation. In preliminary experiments the flow cell was successfully used as microbial fuel cell (MFC) with a potential of +0.4 V vs. Ag/AgCl using <em>Shewanella oneidensis</em> as electroactive model organism. [1]</p> <p>Commonly, graphite-based electrode materials are used in bioelectrochemical systems due to their low costs and high conductivity. However, the hydrophobic and negatively charged surface is not yet optimal for microbial attachment. There are numerous attempts on electrode surface engineering in order to overcome this problem. In the majority of studies the biofilm analysis and evaluation of the attachment takes place at the end of the experiment, neglecting the impacts of the chemical surface properties and initial electrode conditioning during the very beginning of biofilm formation.</p> <p>To investigate initial attachment and biofilm formation in real-time, the transparent ITO-electrode is coated with polyelectrolytes differing in hydrophobicity and polarity to evaluate their effects on the initial surface colonisation by different electroactive microorganisms. Combining CLSM and EIS, both, surface coverage and electrochemical interaction of electrode-associated bacteria can be assessed.</p> <p>With this we aim to understand and ease initial steps of biofilm formation to improve efficiency of bioelectrochemical applications, e.g. with regards to start-up time.</p> <p> </p> <p>[1] Stöckl, M., Schlegel, C., Sydow, A., Holtmann, D., Ulber, R., & Mangold, K. M. (2016). Membrane separated flow cell for parallelized electrochemical impedance spectroscopy and confocal laser scanning microscopy to characterize electro-active microorganisms. <em>Electrochimica Acta</em>, 220, 444-452.</p>

Maria Irene Lopez-Cazares, Jessica Viridiana Garcia-Meza, Erika Roxana Larios Duràn et al.

ECS Meeting Abstracts • 2015

The chalcopyrite is a sulfide mineral (SM), that is the main copper source, which is extracted by oxidative leaching. As initial reaction products, secondary phases of sulfur, such as S n 2- and S 0 are formed [1], which are sulfur chains and sulfur rings [2], respectively. These phases tend to deposited on chalcopyrite surface, limiting ion and electron transferences between mineral and solution, so the reaction kinetic results decresed [1] . One of the options suggested to avoid this condition, is to remove sulfur phases by biooxidation with Acidithiobacillus microorganisms, such as Acidithiobacillus thiooxidans (sulfurooxidizing microorganism SOM) and Leptospirillum sp. (ironoxidizing microorganisms, IOM) [3,4]. It has been found that direct contact mechanisms of chalcopyrite bioleaching occurs by attachment of microorganisms, which is improved by the initial presence of sulfur phases, mainly for Acidithiobacillus thiooxidans . In addition, a different behavior has been observed as a function of kind of sulfur phase, which influences on the physicochemical and biological characteristics of the biofilm developed during the biooxidation [5,6]. Hence, for SOM the hydrophobic composition of EPS (extracellullar polymeric substances) and cell density of the biolm is improved by presence of S 0 on mineral surface, affecting the biooxidation process of chalcopyrite. However, the above has been only evaluated for SOM systems, hence, that would be important analyze the effect of sulfur phases on the performance of IOM systems, due to it will keep the presence of an oxidant agent (ferric iron), which will affect improves the electrochemical process, such as would occur in the SOM+IOM consortia used in the industrial bioleaching process. So, in this work the objective is analyze the electrochemical process of system bacteria - electrolyte – mineral on modified chalcopyrite surface exhibting different sulfur species exposed to SOM and SOM+IOM cultures. For this the chemical changes in electrolyte, and morphological, composition and hydrophobic modifications on surface exposed to microorganisms are correlated with Electrochemical impedance Electrochemical (EIS) and Electrochemical Noise (EN) data obtained for each evaluated condition. Global analysis of the results shows that the presence of microorganisms improves the ionic and electronic activity of interface, due to the initial sulfur phases (S n 2- and S 0 ) generated by potentiostic oxidation were removed. Then, a secuencial and cyclic transformation between several kinds of reactive sulfur species, determined the electroactivity and hydrophobicity of chalcopyrite surface as a function of bioleaching time, which influences the oxidation capacity of microorganisms. In addition, it was found that on S n 2- rich surfaces, oxidation was improved with SOM, by an uniform mechanism of acidic dissolution and through indirect contact, these associated with SOM membrane enzymatic characteristics, according to [2,7]. However, on S 0 rich surfaces, the bacterial activity occurred by direct contact, but was slower than on S n 2- , due to generation of hydrophobic and inactive (passive) sulfur species. Such kind of phases were result of a low amount of EPS-Fe 3+ complexes that limited the ring sulfur activation, based in the reported in [2], and therefore the charge transfer and diffusion processes. On the other hand, SOM+IOM showed higher activity by an uniform mechanism of ferric dissolution on both sulfur phases, but it was mainly by direct contact on initial S 0 surface, generating predominantly hydrophilic and reactive surfaces species at early times, which was associated to higher amount of EPS-Fe 3+ , that contributed with either fast activation of initial ring S 0 [2] and mass transfer. References: [1] Klauber C, Int J Miner Process, 86:1-17 (2008). [2] Meyer B, Chem Rev , 64 (4):429-451 (1964). [3] Pan HD, Yang HY, Tong LL, Zhong CB, Zhao YS Trans Nonferrous Met Soc China 22:2255−226 (2012) [4] Anjum F, Shahid M, Akcil A, Hydrometallurgy 1-12:117-118 (2012). [5] González D, Lara R, Valdez-Pérez D, Alvarado K, Navarro-Contreras H, Cruz R, García-Meza JV Appl Microbiol Biotechnol 93:763–775 (2012). [6] Lara R, García-Meza JV, González I, Cruz R, Appl Microbiol Technol 95, 799 (2012). [7] Franz B, Lichtenberg H, Hormes J, Modrow H, Dahl V, Prange A, Microbiol 153:1268-1274 (2007).

Arnulfo Rojas-Pérez, Delmaliz Barreto-Vázquez, Santosh H. Vijapur et al.

ECS Meeting Abstracts • 2019

The recycling of human urine has become a main research area in wastewater treatment due to the increased demand for water. Urine is composed of 95% water, 2% urea and other organic and inorganic compounds. Urea is a toxic molecule that may cause renal failure and gastrointestinal bleeding. Nevertheless, it is difficult to remove by common methods since it is a small, uncharged molecule. In this work, the use of Proteus vulgaris is proposed, a bacterium that contains urease, to catalyze the urea conversion to ammonia. The latter can then be oxidized by a platinum electrode while producing a current leaving a urea-ammonia-free solution. This system was first tested in synthetic human urine (SHU) simulating the ureolytic bacterium behavior. The ammonia oxidation current (AOC) was evaluated by cyclic voltammetry (CV) using Pt electrode in SHU, obtaining better results when less urea was present in solution. Preliminary, AOC was evaluated while the bacterial grew in Enriched Synthetic Human Urine (SHU + growth factors). The experiment was carried out for 24 hours showing not only bacterial viability and actual growth in the medium but an increased AOC over time.

Konatsu Ichikawa, Taiki Adachi, Keisei Sowa et al.

ECS Meeting Abstracts • 2024

Bioelectrocatalysis is a coupled system with enzymatic and electrode reactions. Some oxidoreductases can directly communicate with electrodes, which is called direct electron transfer (direct ET; DET)-type bioelectrocatalysis. The number of enzymes proceeding with DET-type reactions is still limited, and its mechanism is not fully elucidated. However, it is expected to be applied to electrochemical devices such as biosensors, biofuel cells, and bioreactors, owing to energy efficiency, biocompatibility, and design flexibility. In addition, this reaction is utilized for enzyme characterization based on kinetics and thermodynamics. In particular, a relationship between DET activity and the redox potential can be quickly and precisely characterized. We focused on aldehyde dehydrogenase (ALDH) from Gluconobacter oxydans , a membrane-bound protein catalyzing DET-type acetaldehyde oxidation. In previous studies, the three-dimensional structure of ALDH was elucidated using cryo-electron microscopy analysis (PDB: 8GY3). The structure is composed of the catalytic large subunit (L subunit), the small subunit (S subunit), and the cytochrome c subunit (C subunit). In vivo , electrons extracted from acetaldehyde are transferred to ubiquinone via the catalytic center (molybdenum cofactor; Moco) in the L subunit, two iron-sulfur clusters (FeSs) in the S subunit, and three hemes c in the C subunit, in this order. The ET associated with substrate oxidation through the C subunit is conserved in membrane-bound hemoproteins such as alcohol dehydrogenase, fructose dehydrogenase, and glucose dehydrogenase. These enzymes have similarities in high DET activities, and their variants truncating a C subunit, which are advantageous in ignoring interference of detergents and complexity of the multi-step ET through hemes c , have been characterized. However, such research has not been conducted for ALDH, and ALDH has the unique feature of having two cofactors in the S subunit. In this study, we attempted to quantitatively characterize the ALDH variant deleting the C subunit (ΔC_ALDH), focusing on pH dependence of kinetic and thermodynamic parameters. To construct an expression system of ΔC_ALDH, a plasmid containing genes of L and S subunits of ALDH was transformed into the knock-out strain in which genes of wild-type ALDH were disrupted. ΔC_ALDH was expressed in soluble fraction as expected and successfully purified. Cyclic voltammograms were recorded at ΔC_ALDH-modified multi-walled carbon nanotube-electrodes. The electrode showed clear DET activity, suggesting that the electrode-active site seems to be FeS which is located near the surface of the enzyme. In addition, we investigated the pH dependence of the DET activity and kinetically analyzed the voltammograms using a model in which distribution of enzyme orientation was considered. The kinetic analysis quantitatively estimated the formal potential of the electrode-active site ( E °′ E ), the limiting catalytic current density ( j cat ), and the ratio of the maximum value of the standard rate constant of the heterogeneous ET to the catalytic constant in DET-type reaction ( k ° max / k c,DET ). j cat exponentially increased from pH 2.5 to 5.5 and reached a plateau between pH 6.0 and 8.0, while E °′ E changed by –48 mV pH –1 from pH 2.5 to 5.5 and became constant between pH 6.0 and 8.0. Since the formal potential of acetate/acetaldehyde redox couple ( E °′ S ) changes by –89 mV pH –1 , E °′ E – E °′ S increases as the condition becomes more basic. Then, we focused on a relationship between the potential difference and DET activity. The log ( j cat / mA cm –2 ) vs. E °′ E – E °′ S plot showed a linear increasing region and a constant region independent of E °′ E – E °′ S , as shown in Figure 1. The former slope suggested that DET activity obeyed the ideal linear free energy relationship (LFER) without any specific interaction. In this region, k c,DET was controlled by the potential difference in the ET pathway. When E °′ E – E °′ S is sufficiently large, k c,DET seems to be limited by other factors such as entry of substrate into the catalytic site, a catalytic turnover in Moco, and the intramolecular ET. On the other hand, in the assay with ferricyanide as an alternative electron acceptor, the slope representing the ideal LFER was not observed. We assume that the potential difference between the enzyme and ferricyanide was insufficient, thus the catalytic constant in solution ( k c,solution ) was kinetically analyzed based on the ping-pong bi-bi mechanism considering changes in E °′ E , E °′ S , and the formal potential of ferricyanide/ferrocyanide. Using parameters obtained from the analysis for j cat and k c,solution , Γ E,eff , k ° max , and k c,DET were separately evaluated with an assumption that Γ E,eff was independent of pH. In summary, we quantitively characterized the bioelectrochemical parameters of ΔC_ALDH and compared the properties between DET and ferricyanide reductase activities. This work will be beneficial for understanding ALDH, and comparing it with wild-type ALDH will elucidate the roles of the C subunit. Figure 1

Andrea Schievano, Laura Rago, Andrea Goglio et al.

ECS Meeting Abstracts • 2019

The industrial synthesis (Haber-Bosch process) of mineral-N has been showing its dark side. Facing the enormous challenge of feeding humankind new technological solutions should enable sustainable nitrogen (N) fixation, to preserve soil fertility. We introduce a new type of microbial electrosynthesis, aimed at simultaneously fixing N 2 and inorganic carbon. In this new perspective, the aim is enhancing biological nitrogen fixation by electrostimulation of complex microbial communities, to produce whole biomass, which can be used as soil fertilizer. Two preliminary contributions in this field reported: a) a bioelectrochemical version of the Haber-bosh process, where methyl viologen shuttled electrons to purified nitrogenase enzymes (Milton et al., 2017) and b) the stimulation of N-fixation in a pure planktonic culture of X. autotrophicus by H 2 -evolution with a specific abiotic catalyst (Liu et al., 2017). Here, a cathodic biofilm was enriched in electro-active autotrophic nitrogen fixers, starting from a mixed microbial culture. The cathode, a carbon-fibers conductor, was kept under constant polarization (-0.7 V vs SHE). Biomass (in the biofilm, as well as in the bulk liquid phase) was synthesized at significantly higher rates (up to 18-fold), as compared to controls kept at open circuit (OC). Along over 100 days, electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated to autotrophs (both Archaea and Bacteria ) only in polarized biofilms, while not in OC control. Genes copies encoding for a series of known proteins associated to extracellular electron transfer were double in polarized trials, as compared to controls. The first results of such an approach were recently published in Bioelectrochemistry (Rago et al., 2019). From this proof-of-the-concept, we propose to call this promising field ‘bio-electrochemical nitrogen fixation (e-BNF)’, that deserve future research efforts in both fundamentals and applicative aspects. Liu, C., Sakimoto, K.K., Colón, B.C., Silver, P.A., Nocera, D.G., 2017. Ambient nitrogen reduction cycle using a hybrid inorganic–biological system. Proc. Natl. Acad. Sci. 114, 6450–6455. doi:10.1073/pnas.1706371114 Milton, R.D., Cai, R., Abdellaoui, S., Leech, D., De Lacey, A.L., Pita, M., Minteer, S.D., 2017. Bioelectrochemical Haber–Bosch Process: An Ammonia-Producing H2/N2Fuel Cell. Angew. Chemie - Int. Ed. 56, 2680–2683. doi:10.1002/anie.201612500 Rago, L., Zecchin, S., Villa, F., Goglio, A., Corsini, A., Cavalca, L. & Schievano, A. 2019, ‘Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation’, Bioelectrochemistry, vol. 125, pp. 105–15. Figure 1

Federica Arena, Giorgio Giuffredi, Andrea Perego et al.

ECS Meeting Abstracts • 2019

The ever-increasing worldwide energy demand and anthropogenic emissions produced by the combustion of fossil fuels, along with the consequent increment in the global average temperature, have pushed the scientific community towards the development of energy vectors with minimal carbon footprint. Electrochemical -reduction is an approach that holds potential for exploiting the cyclic reduction and oxidation of carbon-based fuels. As of today, high efficiency in these systems can only be achieved by employing precious metals, which suffer from both low natural availability and high costs as well as unsatisfactory energy efficiencies and lack of conversion product specificity. Recently, the development of a novel hybrid technology based on the combined use of biological organisms or molecules and nanomaterials has created great opportunities to produce renewable fuels and chemicals from the reduction of with a minimal overpotential. According to this, the enzymatic electrosynthesis (EES) exploits pure enzymes to catalyze reactions with higher transformation efficiency, higher activity under controlled experimental conditions and higher selectivity towards both specific substrates and products. The first step of CO 2 reduction enzymatic process consists of the production of formic acid using the catalytic properties of the enzyme formate dehydrogenase (FDH) (EC 1.2.1.2.). Unlike most metallic catalysts, this enzyme reversibly catalyzes the transformation of CO 2 to formate as the only product of the reaction. In this contest, we used the NAD-dependent FDH from the aerobic bacterium Thiobacillus sp. KNK65MA ( Ts FDH) for its superior -reducing activity (K cat = 0.318 s -1 )[1]. Surface chemistry and surface morphology play a key role in the interaction between the enzyme and the electrode, ultimately affecting the successful development of a bioelectrochemical system (BES). In fact, the atomic composition of the material and its structure affect enzyme immobilization, which in turn influences the electrochemical performance of the EES. In this context, titanium nitride (TiN) can be efficiently used as a scaffold for enzyme immobilization by exploiting its surface-exposed Ti 4+ atoms for the binding. As such, TiN has been described as a promising general catalyst support material. Indeed, TiN features high electrical conductivity, good biocompatibility, as well as outstanding oxidation and acid corrosion resistance, together with a hybrid metallic/ceramic behaviour[2]. The aim of this work is to realize a nanostructured TiN scaffold featuring an increased available surface area to enhance the interface between the enzyme and the electrode. To this end, we developed a novel hybrid device where the FDH enzyme from Thiobacillus sp. KNK65MA (EC 1.2.1.2) is deposited on a nanostructured mesoporous support of TiN fabricated by Pulsed Laser Deposition (Fig.1a). This deposition method allows the production of a biocompatible nanostructured support with high surface area and a tree-like morphology. Its high porosity and high specific area maximize the contact with the enzyme, thus improving the efficiency of the EES for reduction. In order to identify the most suitable film morphology, the immobilization process on TiN support with different porosity was assessed by enzymatic assay after drop-casting (active area of 1 cm 2 ). The results show that there is an increase in the amount of Ts FDH that is bound to the TiN nanostructure when the porosity, and therefore the surface area, of the nanostructure increases. For the more porous morphology the percentage of adsorbed Ts FDH is 48%, corresponding to 1 µg of specifically-adsorbed Ts FDH. After, a calibration curve was performed to determine the maximum binding capacity of the TiN support. The result shows that, by increasing the concentration of the drop-casted Ts FDH, the enzyme unit calculated on the surface increases until a Ts FDH loading quantity of 1,14 mg is used, corresponding to 59 µg of immobilized protein. To assess the CO 2 reduction electrochemical performance of the TiN| Ts FDH electrode, chronoamperometric measurements were done at a constant potential of -0.45V RHE . The TiN support alone shows a stable reduction current (-130 µA ), due to hydrogen evolution (HER) occurring on the surface of the electrode (blue line, Figure 1b). Then, we tested the CO 2 reduction activity of the enzyme-conjugated electrode (green trace, Figure 1b). A reductive current density with higher magnitude of -190 µA was registered, showing the actual operation of the BES system. After test, the solution was examined by 1 H NMR spectroscopy. The peak signal at 8.455 ppm in NMR spectra demonstrates that the formic acid is the only product of the catalytic reaction performed by Ts FDH. This result was used to quantify the amount of formic acid synthetized in the BES. During a 3 h reaction period, the electrosynthesis of formic acid was about 5.3±0.4 μmol under potential applied of -0.45V RHE . [1]H.Choe; PLOS ONE (2014). [2]P.H.; Electrochimica Acta( 2010) Figure 1

Taiki Adachi, Kenji Kano, Keisei Sowa et al.

ECS Meeting Abstracts • 2024

In vivo, a variety of enzymatic cascade reactions are working to efficiently and rapidly metabolize biomolecules. Oxidoreductases especially play key roles in biochemical redox reactions such as fermentation, respiration, and photosynthesis, which might lead to efficient conversion of eco-friendly materials and production of useful compounds. Some enzymatic redox reactions can be artificially coupled with electrode reactions, which is called bioelectrocatalysis. Particularly, an electrical communication without any external electron mediators is called direct electron transfer (DET)-type bioelectrocatalysis, which can be an analytical system evaluating kinetic and thermodynamic characteristics of enzymes, and are expected to be applied to biomimetic devices such as biofuel cells, bioreactors, and biosensors. We focused on two DET-type enzymes: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) from acetic acid bacteria ( Gluconobacter oxydans ). Both enzymes form heterotrimeric structures composed of the catalytic large subunit, the chaperonic small subunit, and the membrane-bound cytochrome c subunit. They physiologically play key roles in the respiration, and the electrons are transferred from substrates to ubiquinone in the periplasmic space. Although DET activities of ADH and ALDH have been already reported, their three-dimensional (3D) structures remain unknown, which prevents the elucidation of detailed electron transfer pathways and improved DET-type bioelectrocatalysis of ADH and ALDH. In this study, we attempted to establish the bienzymatic cascade for bioelectrochemical 4-electron oxidation of ethanol into acetate via acetaldehyde, using ADH and ALDH. To optimize the surface structure of electrodes for the two enzymes by considering their structural characteristics, we firstly elucidated the 3D structures of ADH and ALDH using cryo-electron microscopy analysis. The 3D structures were reconstructed with a 2.5 Å resolution for ADH and a 2.7 Å resolution for ALDH, respectively. Pyrroloquinoline quinone and four hemes c were resolved in ADH, while a molybdenum cofactor, two iron-sulfur clusters, and three hemes c were resolved in ALDH. Cyclic voltammograms were then recorded at multi-walled carbon nanotube-modified glassy carbon electrodes (CNT/GCs) functionalized with five pyrene derivatives and the enzyme (ADH or ALDH). Regardless of pyrene modification, all prepared electrodes performed clear DET-type ethanol oxidation by ADH and acetaldehyde oxidation by ALDH, respectively, and the 1-pyrenecarboxylic acid (PyCOOH)-functionalized CNT/GC showed the best catalytic properties for both ADH and ALDH. Based on the electrochemical results, PyCOOH-functionalized CNT/GC was selected as an electrode platform for bienzymatic electrochemical cascade. The electrodes were functionalized with a mixture of ADH and ALDH. The molar concentrations of ADH and ALDH ( c 1 and c 2 , respectively) were variously controlled under the condition that c 1 + c 2 was constant. The apparent DET-type current density for ethanol oxidation reached a maximum around log ( c 1 / c 2 ) = 0.5, which was higher than that at c 1 / c 2 = ∞ (only ADH). Such increase in the DET-type current density indicates that acetaldehyde produced by ADH was subsequently oxidized by ALDH, which means a bienzymatic cascade. A mathematical model for a bienzymatic DET-type cascade reaction was constructed using the experimental results. These calculations indicated that the ratio of the amounts and catalytic constants of the two enzymes was a key factor controlling the performance of the bienzymatic cascade. In addition, the nanostructure of the enzyme-electrode interface which seems to affect diffusion of the intermediate product was also important for improving cascade efficiency. An ethanol/air biofuel cell was finally constructed with a bienzyme (ADH and ALDH)-functionalized bioanode and a bilirubin oxidase (BOD)-functionalized biocathode. The open-circuit voltage, the maximum current density, and the maximum power density were 0.75 ± 0.02 V, 2.69 ± 0.09 mA cm –2 , and 0.48 ± 0.01 mW cm –2 , respectively. Comparing these characteristics with those of a biofuel cell without ALDH, the performances were improved by ALDH co-adsorption. The ethanol/air biofuel cell worked much better than any other ethanol biofuel cells reported to date. The Faraday efficiency for acetate production of the ethanol/air biofuel cell reached 100 ± 4%, which indicates that the bienzymatic DET-type cascade using ADH and ALDH performed highly efficient 4-electron oxidation of ethanol into acetate. A conceptual diagram of the system is shown in the attached figure. These works will enhance the utilization of biomass fuels and lead to a low-carbon society. These discussions also suggest that the design of the nanostructured interface between the catalysts and electrodes are important for efficient turnover of the intermediate product in the multi-catalytic cascade system. Figure 1

Li Wang, Yang Sun, Ning Hu et al.

ECS Meeting Abstracts • 2016

The Bio-electrochemical catalysis reactor (BECR) is employed to purify SOx, NOx, carbon dioxide and other pollutants from mineral processing flue gases in mineral processing. They are converted into sulphur and nitrogen and high added-value biofuels via biological agent of seperating air/pollutants and bioelectrocatalysis reversal process (BECRP). Biofuel producing bacteria and BECR reactors are coupled to a system, and the BECRP is utilized and realized to purify mineral processing flue gas and convert carbon dioxide biofuel in the reactors. The metabolic products, mineral processing flue gas components of influx and exhaust and other processing parameters are analysed by using online Micro-GC, HPLC-MS, and etc. The influences of microbial metabolic pathway of the BECRP and low voltage loading on the bacteria and the electrode reaction mechanism in the electrode process are investigated. The multi-variable bioelectrochemical transition matrix and optimal parameters are established to improve the flue gas purification efficiency and the conversion rate of carbon dioxide.

E. Lavrentyeva, T. Banzaraktsaeva, V. Dambaev et al.

IOP Conference Series: Earth and Environmental Science • 2021

We studied the taxonomic diversity of microbial mat in the Uro hot spring (the Baikal rift zone, BRZ) with temperatures of 62°C (Ur-3) and 56°C (Ur-4). According to the results of high-throughput sequencing, the composition of the community is represented by various phylogenetic groups Cyanobacteria, Proteobacteria, Deinococcus-Thermus, Chloroflexi, Firmicutes, and Bacteroidetes involved in different stages of organic matter production and degradation in microbial mats. According to metagenomic analysis, there is a wide variety of natural peptidases, enhancing the potential of their specialised functions of energy and substance conversion in microbial mats.

Laurentia Artiomov

5th International Scientific Conference on Microbial Biotechnology • 2022

The abundance and diversity of microorganisms in the biosphere reflects their ability to accumulate energy from various organic and inorganic substrates as well as the ability to grow in a wide range of natural conditions. Most often, the complexity of microbial communities is dependent on the conditions offered by the habitat for its colonization and the availability for energy and carbon sources. In most cases, habitats offer extreme climatic or environmental conditions, thus limiting the number of species that may exist in such an ecological niche. An example of such natural selection can be found in endolytic habitats which are colonized by microorganisms involved in their biodegradation or biodeterioration. This paper is a holistic approach to such microorganisms and the types of substrates they can colonize

J. Madden, Gabriela Marcano, Stephen Taylor et al.

Proceedings of the 20th ACM Conference on Embedded Networked Sensor Systems • 2022

Soil microbial fuel cells are a promising source of energy for outdoor sensor networks. These biological systems are sensitive to environmental conditions, therefore more data is needed on their behavior "in the wild" to enable the creation of an energy system capable of being widely deployed. Prior work on early characterization of microbial fuel cells relied on extremely accurate, but expensive, logging hardware. To scale up the number of deployment sites, we present custom logging hardware, specially designed to accurately monitor the behavior of microbial fuel cells at low cost. This paper describes the design and evaluation of the board, which is open source and freely available on GitHub.

Yang Yang, Lei Wang, Yuanqi Wang et al.

Proceedings of the 2018 International Conference on Electronics and Electrical Engineering Technology • 2018

Microbial power generation is the use of microbial energy to generate electricity. This paper is mainly designed to study the microbial power generation system in the energy storage system. Microbial power generation voltage is only 0.6v and this voltage is very small, The electricity from the microbes is first charged by a group of parallel super capacitors. Then the super capacitor is transformed into a series state, and then through the DC-DC boost circuit to store electricity. This can store electricity exponentially and Long time power supply for load. This process, the switching of the series and parallel state of the super capacitor is controlled by a single cylinder which is connected with the circuit. The whole system can raise the voltage of microbes from 0.6V to 15V.In addition, the energy storage scheme discussed in this paper has practical guiding significance, and can guide the production of the corresponding objects.

Boyu Ma

Second International Conference on Biological Engineering and Medical Science (ICBioMed 2022) • 2023

Microorganism is an important part of soil ecosystem and the main promoter of biosphere material circulation and energy flow. It plays an important role in biogeochemical cycles such as decomposition of soil organic matter, nutrient release and energy transfer. Its diversity directly affects soil quality and determines whether crops can grow healthily. In this research, various research methods of soil microbial diversity were reviewed, and the advantages and disadvantages of each method were compared. At the same time, some views on the shortcomings and development of microbial diversity research were put forward. The main research methods of soil microbial diversity were introduced in order to provide theoretical basis for soil microbial research.

Taylor L. Davis, Blake Dirks, Elvis A. Carnero et al.

medRxiv • 2025

Abstract Colonic microorganisms have been linked to human health and disease, specifically metabolic disease states such as obesity, but causal relationships remain to be established. Previous work demonstrated that interactions between the host’s diet and intestinal microbiome were associated with human energy balance by affecting the human’s energy absorption, quantified by metabolizable energy. We developed the Digestion, Absorption and Microbial Metabolism (DAMM) model, which explicitly accounts for the energy contributions of the colonic microbial community by: 1) breaking down the diet composition into the gross energy of the individual macronutrients, 2) calculating direct absorption in the upper gastrointestinal tract, 3) using microbial stoichiometry to estimate the consumption of the remaining unabsorbed nutrients by microbes in the large intestine, 4) quantifying predicted production of microbial products (short-chain fatty acids (SCFA) and methane) in the colon, and 5) estimating absorption from the colonic tract to the host. When used to predict the results from a clinical study that compared two distinctly different diets, the DAMM model captured the directionality and magnitude of change in measured metabolizable chemical oxygen demand (which can be converted to metabolizable energy), improved on the accuracy of predictions compared to the Atwater factors by reducing systematic bias on one of the diets, and estimated substrate availability within the colon and rate of production of microbially derived short-chain fatty acids. Measured methane concentrations, combined with findings from the DAMM model, support the hypothesis that methanogens accumulated in mucosal biofilms in participants harboring methanogens. Model outputs also support that colonic transit time directly influenced SCFA absorption rates. The DAMM model now can be linked to existing human models that predict changes in body energy stores to extend our understanding of how microbial metabolic processes affect macronutrient absorption and metabolizable energy.

Elaina M. Blair, Noa J. Margalith, Michelle A. O’Malley

Microbial Ecology • 2025

Abstract Desert tortoises play ecologically significant roles, including plant seed dispersal and mineral cycling, and yet little is known about microbial members that are critical to their gut and overall health. Tortoises consume recalcitrant plant material, which their gut microbiota degrades and converts into usable metabolites and nutrients for the tortoise. Findings from tortoise gut microbiomes may translate well into biotechnological applications as these microbes have evolved to efficiently degrade recalcitrant substrates and generate useful products. In this study, we cultivated microbial communities from desert tortoise fecal samples following a targeted anaerobic enrichment for microbes involved in deconstruction and utilization of plant biomass. We employed 16S rRNA amplicon sequencing to compare cultivated communities to initial fecal source material and found high abundances of Firmicutes and Bacteroidota typically associated with biomass deconstruction in all cultivated samples. Significantly decreased microbial diversity was observed in the cultivated microbial communities, yet several key taxa thrived in lignocellulose enrichments, including Lachnospiraceae and Enterococcus . Additionally, cultivated communities produced short-chain fatty acids under anaerobic conditions, and their growth and metabolic output provide evidence of their viability in the initial fecal communities. Overall, this study adds to the limited understanding of reptilian herbivore microbiota, and offers a path towards biotechnological translation based on the ability of the cultivated communities to convert lignocellulose directly to acetate, propionate, and butyrate.

Alexander Tunik, Mikhail Tolstoy, Devard Stom et al.

IOP Conference Series: Materials Science and Engineering • 2019

Abstract The results of studies of a multifunctional energy container are given. The use of microbial-fuel cells for generating electricity, as well as flat liquid solar collectors for generating thermal energy, has been investigated in the energy container.

Valentina Josan, Inna Rastimeşina, О. Postolaky et al.

5th International Scientific Conference on Microbial Biotechnology • 2022

It is well known that large quantities of non-recyclable plastic, namely low-density polyethylene (LDPE), represent a major pollution problem in the environment, thus a solution would be its degradation through the adhesion and accumulation of microorganisms’ consortia on the polyethylene surface. The microbial complexes that are involved in the decomposition of non-recyclable plastic were created in the polluted soil collected from the landfill situated near Slobozia-Dusca village. Consortia of microorganisms isolated from soil LDPE-treated under the aerobic conditions were inoculated into the liquid mineral salt media MSM 2 and MSM 4 to obtain enrichment cultures. MSM 2 medium was favoring the growth of micromycetes and MSM 4 medium – the growth of bacteria. Four microbial consortia were obtained. Figure 1. Composition of consortia isolated from soil treated with LDPE under aerobic conditions. Analyzing the consortia of microorganisms obtained, which includes mycelial fungi and bacteria, we observed that the fungi are predominant, for the most part representatives of the Trichoderma spp., Penicillium spp., and Fusarium spp., while for bacteria only the genus Pseudomonas spp. was identified (fig. 1.). The results demonstrate that after 100 days of cultivation, the microorganisms in the consortia retain their viability, the titer being from 7.00 × 106 CFU/mL to 26.00 × 106 UFC/mL. In conclusion, that complexes of microorganisms isolated from polluted soil treated with LDPE can use plastic as a potential source of carbon and/or energy.

Kenneth Timmis, Juan Luis Ramos, Willy Verstraete

Microbial Biotechnology • 2022

The core responsibility of governments is the security of their citizens, and this means inter alia protecting their safety, nutrition and health. Microbiology and microbial biotechnology have key roles to play in improving supply security of essential resources. In this paper, we discuss the urgent need to fully and immediately exploit existing microbial biotechnologies to maximize supply security of energy, food and medical supplies, and of waste management, and to invest in new research specifically targetting supply security of essential resources.

Zane Kusnere, Vladimirs Kirsanovs, Dace Lauka et al.

CONECT. International Scientific Conference of Environmental and Climate Technologies • 2025

Syngas biomethanation has emerged as a promising technology for converting synthesis gas (CO, H2, and CO2) into renewable methane, offering a sustainable alternative to fossil-based natural gas. However, despite significant progress at the laboratory scale, the transition to industrial applications remains hindered by multiple challenges spanning microbial efficiency, reactor design, process optimization, and large-scale feasibility. At the fundamental level, mass transfer limitations significantly constrain the biological conversion of syngas, with poor gas-liquid diffusion of CO and H2 affecting microbial metabolism. Moreover, the adaptation of microbial consortia to varying syngas compositions remains insufficiently understood, particularly regarding the dominant pathways under mesophilic and thermophilic conditions. Reactor design further exacerbates these challenges, with current configurations (continuous stirred-tank reactors, packed bed reactors, and membrane bioreactors) struggling to achieve efficient syngas conversion at high productivity rates. Process parameters such as temperature, H2/CO ratio, and trace element supplementation also require fine-tuning to enhance methane yields while maintaining process stability. While small-scale experiments have demonstrated promising results, scaling up remains a major hurdle due to economic constraints, reactor operational challenges, and the need for reliable feedstock supply. Additionally, the integration of syngas biomethanation with existing energy infrastructure, including power-to-gas technologies and anaerobic digestion systems, requires further investigation to ensure economic viability and process efficiency. This review systematically explores these multi-scale challenges, from bench-scale research to commercial deployment, highlighting key research gaps and potential strategies to accelerate the transition of syngas biomethanation from laboratory studies to industrial reality.

Shaunak V Potdar, Mohamed Shazin, Geetha Kannan

Journal of Physics: Conference Series • 2019

Abstract A microbial fuel cell (MFC) is a sustainable energy source which hopes to meet the growing demand of energy in the world by providing bioelectricity. The microbes like bacteria help produce current and voltage by metabolizing the carbon source into ions which are accepted at their respective electrodes. The prototype cell designed by our team is novel, cost effective, portable and environment friendly. This microbial fuel cell is a two chambered setup containing four graphite electrodes as the anode and four aluminum electrodes as the cathode. The MFC has been optimized under various experimental condition which includes sugar concentration, surface area of the electrodes, material of the electrodes as well as the effects of reducing salts on the current and voltage.

Mayumi Seto, Michio Kondoh

ARPHA Conference Abstracts • 2023

Microorganisms thriving in low-energy ecosystems have evolved diverse strategies to sustain life, including individual-level energy conservation, optimizing energy utilization through interspecies competition, and mutually beneficial interspecies syntrophy. This study introduces a novel community-level strategy to enhance energy efficiency. We employed an oxidation-reduction (redox) reaction network model to capture the intricate metabolic interactions within microbial communities. Our findings highlight the importance of microbial functional diversity in facilitating metabolic handoffs, leading to an improved energy utilization efficiency. Moreover, the mutualistic division of labor and the resulting complexity of redox pathways actively facilitate material cycling, thereby enhancing energy exploitation. These findings provide new insights into the potential of self-organized ecological interactions to develop efficient energy utilization strategies, with significant implications for the functioning and evolution of microbial ecosystems.

F. Alsaeed, M. Baran

IET Conference Proceedings • 2021

Recently, battery energy storage (BES) has emerged as an economically viable technology to be adopted in large-scale photovoltaic (PV) and wind farms to facilitate their integration into the system and increase their economic value. This paper focuses on the determining a proper BES for such a system that will enable the system to respond to the power price variations and thus maximize the BES benefits. Additionally, this paper proposes a detailed dispatching scheme that can handle various operation constraints in order to maximize the BES benefits. This paper also takes into account the factors affecting the degradation of BES during its operation and shows that this is a critical factor in determining economic viability of the BES. A case study for a 300 MW solar power plant is given to illustrate the proposed method and assess the economic viability of the storage for this case. The results show the importance of adopting a detailed BES model to improve the accuracy of the estimated economic benefits.

T. Allen, S. Bruemmer, M. Kassner et al.

• 2002

On March 18-21, 2002, the Department of Energy, Office of Nuclear Energy, Science, and Technology (NE) and the Office of Basic Energy Sciences (BES) sponsored a workshop to identify needs and opportunities for materials research aimed at performance improvements of structural materials in higher temperature reactors. The workshop focused discussion around the reactor concepts proposed as part of the Generation IV Nuclear Energy System Roadmap. The goal of the Generation IV initiative is to make revolutionary improvements in nuclear energy system design in the areas of sustainability, economics, safety and reliability. The Generation IV Nuclear Energy Systems Roadmap working groups have identified operation at higher temperature as an important step in improving economic performance and providing a means for nuclear energy to support thermochemical production of hydrogen. However, the move to higher operating temperatures will require the development and qualification of advanced materials to perform in the more challenging environment. As part of the process of developing advanced materials for these reactor concepts, a fundamental understanding of materials behavior must be established and the data-base defining critical performance limitations of these materials under irradiation must be developed. This workshop reviewed potential reactor designs and operating regimes, potential materials for application in high-temperature reactor environments, anticipated degradation mechanisms, and research necessary to understand and develop reactor materials capable of satisfactory performance while subject to irradiation damage at high temperature. The workshop brought together experts from the reactor materials and fundamental materials science communities to identify research and development needs and opportunities to provide optimum high temperature nuclear energy system structural materials.

Cong Tu, Lena Q. Ma, Bhaskar Bondada

Journal of Environmental Quality • 2002

ABSTRACT The unique property of arsenic hyperaccumulation by the newly discovered Chinese brake ( Pteris vittata L.) fern is of great significance in the phytoremediation of arsenic‐contaminated soils. The objectives of this study were to (i) examine arsenic accumulation characterized by its distribution pattern in Chinese brake, and (ii) assess the phytoextraction potential of the plant. Young ferns with five or six fronds were transferred to an arsenic‐contaminated soil containing 98 mg As kg −1 and grown for 20 wk in a greenhouse. At harvest, the Chinese brake produced a total dry biomass of 18 g plant −1 Arsenic concentration in the fronds was 6000 mg kg −1 dry mass after 8 wk of transplanting, and it increased to 7230 mg kg −1 after 20 wk with a bioconcentration factor (ratio of plant arsenic concentration to water‐soluble arsenic in soil) of 1450 and a translocation factor (ratio of arsenic concentration in shoot to that in root) of 24. The arsenic concentrations increased as the fronds aged, with the old fronds accumulating as much as 13 800 mg As kg −1 Most (approximately 90%) of the arsenic taken up by the Chinese brake was transported to the fronds, with the lowest arsenic concentrations in roots. About 26% of the initial soil arsenic was removed by the plant after 20 wk of transplanting. Our data suggest that the arsenic hyperaccumulating property of the Chinese brake could be exploited on a large scale to remediate arsenic contaminated soils.

B. Telsang, S. Djouadi, M. Olama et al.

2018 9th IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG) • 2018

With the increasing demand for energy in day-to-day life, the need for integrating renewable energy is growing. In this paper, we take a step in addressing this challenge by employing solar photovoltaic (PV) energy to maintain indoor temperatures in buildings. The objective we aim to meet is to consume as much of the generated PV energy as possible locally while maintaining the indoor comfort temperatures. We set this objective to reduce wastage of renewable energy and cut down the need for storage devices. We formulate a thermal model of the building Heating Ventilation and Air Conditioning (HVAC) system and employ the model-free control (MFC) technique to achieve the defined objective. Simulation results illustrate that the performance of the MFC technique, in terms of indoor temperature and total energy consumption tracking errors, is comparable with that of the recently developed augmented model predictive control technique. In addition, the MFC is computationally light and easily deployable on small embedded devices. Furthermore, we analyze the relationship between the generated PV energy and the required energy consumption of the buildings, and the results show that this relationship is linear, indicating that the developed framework can be directly implemented for a certain number of buildings given an arbitrary PV profile.

O. Bara, M. Olama, S. Djouadi et al.

2017 North American Power Symposium (NAPS) • 2017

This paper presents a new model-free control (MFC) mechanism that enables the local distribution level circuit consumption of the photovoltaic (PV) generation by local building loads, in particular, distributed heating, ventilation and air conditioning (HVAC) units. The local consumption of PV generation will help minimize the impact of PV generation on the distribution grid, reduce the required battery storage capacity for PV penetration, and increase solar PV generation penetration levels. The proposed MFC approach with its corresponding intelligent controllers does not require any precise model for buildings, where a reliable modeling is a demanding task. Even when assuming the availability of a good model, the various building architectures would compromise the performance objectives of any model-based control strategy. The objective is to consume most of the PV generation locally while maintaining occupants comfort and physical constraints of HVAC units. That is, by enabling proper scheduling of responsive loads temporally and spatially to minimize the difference between demand and PV production, it would be possible to reduce voltage variations and two-way power flow. Computer simulations show promising results where a significant proportion of the PV generation can be consumed by building HVAC units with the help of intelligent control.

Milad Andalibi, Mojtaba Hajihosseini, M. Gheisarnejad et al.

2020 IEEE 11th International Symposium on Power Electronics for Distributed Generation Systems (PEDG) • 2020

Today, regarding the increase in using renewable energy resources, DC/DC boost converters have become more popular than in the past, in particular, the multilevel DC/DC boost converter due to its high voltage gain and simple components to implement. However, the constant power loads (CPLs) are contributed to instability in these converters because of the intense non-linear nature of CPLs. This paper intends to address this issue by applying a new method based on a combination of the Nonlinear Integral-Backstepping technique (NIB) and Model-Free Control (MFC) to a DC/DC multilevel boost converter (MBC) in presence of a non-ideal CPL. To validate the effectiveness of the proposed controller theoretical analysis and simulation results are represented.

Y.-X. Zhang, Shao‐Long Zhong, Q. Feng et al.

IET Conference Proceedings • 2021

Metallized film capacitors (MFC) are important devices in many industries, while its voltage drop obstacles the exertion of its energy storage characteristics. Therefore, it has become an important research topic to clarify the voltage drop law of MFC and predict the voltage drop of MFC. At first, this paper gives the voltage drop test circuit of MFC. Then, the classical voltage drop model, power function, 9-order polynomial and smoothing spline are used to fit the voltage drop data, and the voltage drop values are predicted based on the fitting results. At final, fitting and prediction performance of these methods are compared, and the research direction of how to improve the prediction accuracy is pointed out.

Xi Fu, Wenzhou Ruan, Qing Guo et al.

2022 IEEE MTT-S International Wireless Symposium (IWS) • 2022

An ultra-wide band tile-type Transmit/Receive module (T/R module) with the characteristics of high integration, small volume, light-weight is presented in this paper. The proposed T/R module can realize transmit/receive signal amplification, amplitude and phase control. In electrical design, two 2-channels multi-function MMICs (MFC) are applied to provide the amplitude and phase control of RF signal. And it is remarkable that large, the MFC is a three-dimensional (3D) chip which achieved by stacking digital circuits on top of the microwave circuits to increase densities. And 4 RF front modules are applied to realize transmit/receive signal amplification. The designed T/R module provides above 30dB of receive gain with Noise Figure (NF) better than 2.5dB, and up to 40dBm of pulsed power with about 35% of power added efficiency (PAE). In mechanical design, a newly assembly method of 3D vertical interconnection technology in the highly integrated packaging TR module is proposed. Signals transmission between the proposed TR module and the external system are achieved by fuzz-button connectors to form a vertical interconnection structure. The designed 4-channels T/R module is about 38mm38mm*8mm, and the total weight is 30g.

S. A. Verne, Javier Donati

2024 Argentine Conference on Electronics (CAE) • 2024

In this work, a programmable high voltage signal generator for driving macro-fiber composite (MFC) actuators is presented. Peak to peak output voltages on the range of kilo volts is achieved through an H-bridge three-level Neutral Point Clamp (NPC) inverter. The inverter delivers DC and AC output voltages both bipolar or unipolar as required for driving either unimorph or bimorph MFC devices. The modulation of the inverter is based on a level shifted multi-carrier PWM which is implemented by using the motor control module of a low cost ESP32 microcontroller. The complete setup is described which includes DC bus supply, isolated driver modules and output filter.

Hao Sun, Mengqi Zhang, Xinrong Li et al.

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023) • 2024

Due to GMR biosensor has the advantages of miniaturization, low-power consumption and rapid detection, so it has a widely application in bacterial, viral and cancer biomarker detection. However, the current GMR biosensor has relatively low detection sensitivity in biotarget detection, that limiting the development in biomedical detection applications rapidly. As we know, the magnetic flux concentrator (MFC) can improve detection sensitivity and resolution of the GMR sensor. So, a new micro-funnel-shaped MFC is proposed for GMR biosensor and analyzed by finite element method (FEM). The MFC shape, size and distribution of magnetic labels were investigated. The simulation results indicate that the signal gain can be increased by 30% with the hypotenuse of MFC. The distribution of magnetic labels was arranged horizontally along the X-axis can generate high magnetic field intensity and the strongest magnetic gain. The simulation results has certain theoretical guidance for high sensitivity GMR biosensors design.

G. Puggioni, A. Carucci, E. Dessì et al.

Global NEST International Conference on Environmental Science & Technology • 2022

Sustainable exploitation of coastal aquifers is often hindered by the presence of contaminants and high salinity levels. This study proves for the first time the electro-bioremediation of nitrate contaminated saline groundwater. Two 3-chamber bioelectrochemical systems (BES) were operated in potentiostatic mode for the treatment of a synthetic medium mimicking saline groundwater from the Nitrate Vulnerable Zone of Arborea (Sardinia, Italy). This groundwater is characterised by high nitrate concentrations (>33 mgNO3--N/L) and conductivity (>3.5 mS/cm). The electrochemically active microbial community grown on the surface of the biocathode was able to achieve nitrate removal rates and efficiencies of 6.8±0.4 mg/L·d and 87±2%, respectively. Conductivity significantly decreased (from 4.11±0.2 to 0.17±0.2 mS/cm) by enhancing the electromigration of ions from the middle chamber to the peripheral anodic and bio-cathodic chambers. Under the applied conditions, WHO (World Health Organization) drinking water threshold limits for nitrate (11.3 mgNO3--N/L) and conductivity (2.5 mS/cm) were satisfied. Moreover, high chloride migration was observed (63±7 mg/L·d), suggesting its possible recovery as chlorine in the anodic chamber using a specific electrode (Ti-MMO), within a circular economy-based approach. The results pave the way to the potential development of a new electro-bioremediation technology for water recovery (i.e., simultaneous denitrification and desalination) and sustainable chemicals production (i.e., chlorine).

S. Keller

2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers) • 2021

In bioelectrochemical applications, cells are typically incubated on 2D electrodes. The major limitation of this approach is that planar electrode geometry poorly mimics the natural environment of the cells. 3D polymer scaffolds have been developed to provide a more realistic environment for the cells but these structures usually lack integrated sensor functionality to perform in situ measurements in the 3D cell culture. Here, we address these limitations and demonstrate the in situ electrochemical analysis of alkaline phosphatase (ALP) activity in a 3D bone tissue model with integrated electrochemical sensing using 3D pyrolytic carbon microelectrodes. Furthermore, we integrate pyrolytic carbon electrodes on an optical fibre to obtain a leaky optoelectrical fibre (LOEF). With the LOEF serving as a smart scaffold, we demonstrate the combined optical stimulation of optogenetially modified human neural stem cells (hNSC) and electrochemical recording of the resulting release of the neurotransmitter dopamine.

Xilai Ma

Proceedings of the 11th International Conference on Biomedical Engineering and Bioinformatics • 2022

: Due to the potential risks to human health and ecosystems, antibiotics contamination is an emerging environmental concern. Currently, numerous technologies have been widely explored for the removal of antibiotics from wastewater, including membrane bioreactor, biological process, bioelectrochemical system, constructed wetland and microalgae. In this review, the fundamental mechanisms and removal efficiency of such technologies were discussed. Besides, current challenges and further direction of the antibiotic removal are present, in which the recovery of antibiotics was highlighted. Thus, a shift of antibiotics from the removal to recovery would be a focus in the future for the sustainable development of society.

Segundo Jonathan Rojas Flores, Santiago M. Benites, M. D. L. Cruz-Noriega et al.

Journal of Physics: Conference Series • 2024

Microbial fuel cells are a bioelectrochemical technology that uses different types of waste as fuel sources to generate sustainable and environmentally friendly electricity. Various MFCs have been developed, with the electrode used being a crucial problem due to its high manufacturing cost. This research shows that electrodes can be manufactured quickly and economically using activated carbon (100 g), sugar (80 g), ethanol (250 ml), and pine resin (200 g). For its demonstration, grape waste was used in a single-chamber MFC for 35 days. The manufactured electrode generated a Rint. of 18.471 ± 2.475 Ω, whose current density was 8.348 ±0.768 mW/cm2 at a current density of 5.166 A/cm2. The electrical potential shown was 0.889 ± 0.017 V and 4.571 ± 0.061 mA, with an ORPmax of 81.495 ± 1.874 mV, operating at a pH of 7.26 ±0.19. The micrographs made by scanning electron microscopy showed porous surfaces with carbonaceous substances in the final monitoring stage. These preliminary results showed excellent performance of the electrodes, showing their potential for use in MFCs in an economical way.

D. Sepúlveda, M. A. Aroca, Andres Varela et al.

Sensors • 2017

Bioelectrochemical sensing of Mycobacterium tuberculosis through electro-immunosensors is a promising technique to detect relevant analytes. In general, immunosensors require the formation of organic assemblies by the adsorption of molecular constituents. Moreover, they depend on the correct immobilization of the bio-recognition element in the biosensor. These procedures cannot be easily monitored without the use of invasive methods. In this work, an impedance analysis technique was used, as a non-invasive method, to measure and differentiate the manufacturing stages of the sensors. Biomicrosystems were fabricated through physical vapor deposition (PVD) of 80 nm Au nanolayers on 35 µm copper surfaces. Later, the surface was modified through thiolation methods generating a self-assembled-monolayer (SAM) with 20 mM 4-aminothiophenol (4-ATP) on which a polyclonal antibody (pAb) was covalently attached. Using impedance analysis, every step of the electro-immunosensor fabrication protocol was characterized using 40 independent replicas. Results showed that, compared to the negative controls, distilled water, and 0.5 µg/mL HSA, a maximum variation of 171% between each replica was achieved when compared to samples containing 0.5 µg/mL of ESAT-6 M. tuberculosis immunodominant protein. Therefore, this development validates a non-invasive method to electrically monitor the assembly process of electro-immunosensors and a tool for its further measure for detection of relevant antigens.

H. Maeda, M. Ikarashi, N. Fukushima et al.

SPE Asia Pacific Unconventional Resources Conference and Exhibition • 2015

Abstract As potential CO2 geological storage site in CCS, utilization of depleted oil/gas reservoirs and aquifer has been proposed. The long-term aim of this research is to establish a biotechnological system to microbiologically convert geologically stored CO2 into methane. Our recent study revealed that methanogen and exoelectrogen inhabiting subsurface reservoir are involved in the recently discovered bioelectrochemical reaction called electromethanogenesis (CO2 + 8H++ 8e− → CH4 + 2H2O). In this reaction, methanogen receives proton from reservoir brine and electron from a solid electrode. As a result, reduces CO2 into methane. Required electricity for the methane conversion can be obtained from renewable energy sources such as wind or photovoltaic power generations. Single-chambered electromethanogenic reactors were used for an evaluation. The reactors were inoculated with reservoir brine anaerobically collected from Yabase oil field in Japan. Each reactor headspace was filled with mixed gases of N2/CO2 (80/20). The reactors were incubated at 55°C with an applied voltage of 0.75 V. The reactors produced methane at a rate of 386mmol/day m−2. The current-methane conversion efficiency was almost 100%. On the other hand, no significant methane production was detected in the reactors without applied voltage. To investigate the mechanism of electromethanogenic reaction, the phylogenetic diversity of the microbes on the cathode was analyzed. The result shows, as for archaea, methanogen closely related to Methanothermobacter thermoautotrophicus dominated. On the other hand, as for bacteria, Thermincola ferriacetica, one of the exoelectrogen, was the dominant spices. Our experimental research demonstrated for the first time that the possibility of bioelectrochemical methane conversion of carbon dioxide by utilizing microbes indigenous to depleted oil fields. The final goal of this research is to establish the "Subsurface Methane Regeneration" system, combining CCS and biotechnology, in which geologically-stored CO2 is converted into CH4 by bio-electrochemical process called "Electromethanogenesis".

Andris R. Abele

1st International Fuel Cell Science, Engineering and Technology Conference • 2003

On-board storage and handling of hydrogen continues to be a major challenge on the road to the widespread commercialization of hydrogen fuel cell vehicles. QUANTUM Fuel Systems Technologies WorldWide, Inc. (QUANTUM) is developing a number of advanced technologies in response to the demand by its customers for compact, lightweight, safe, robust, and cost-effective hydrogen fuel systems. QUANTUM approaches hydrogen storage and handling as an engineered system integrated into the design of the vehicle. These engineered systems comprise advanced storage, regulation, metering, and electronic controls developed by QUANTUM. In 2001, QUANTUM validated, commercialized, and began production of lightweight compressed hydrogen storage systems. The first commercial products include storage technologies that achieved 7.5 to 8.5 percent hydrogen storage by weight at 350 bar (5,000 psi). QUANTUM has also received German TUV regulatory approval for its 700 bar (10,000-psi) TriShield10™ hydrogen storage cylinder, based on hydrogen standards developed by the European Integrated Hydrogen Project (EIHP). QUANTUM has patented an In-Tank Regulator for use with hydrogen and CNG, which have applications in both fuel cell and alternative fuel vehicle markets. To supplement the inherent safety features designed into the new 700 bar storage tank, QUANTUM’s patented 700 bar In-Tank Regulator provides additional safety by confining the high pressure in the tank and allowing only a maximum delivery pressure of 10 bar (150-psi) outside the storage system. This paper describes initial applications for these hydrogen fuel systems, which have included fuel cell automobiles, buses, and hydrogen refueling stations.

Jing Chen, Juan Ge, Baolin Guo et al.

Journal of Materials Chemistry B • 2016

A conveniently fabricated electroactive nanofibrous composite scaffold serves as a sustained drug release system and promotes myoblast differentiation.

Rocio López‐Leal, Manuel Octavio Fuentez‐Torres, María Esther Sánchez‐Castro et al.

Energy Technology • 2025

Developing cost‐effective technology for overall electrochemical water splitting requires multifunctional nanocatalysts with reduced Pt‐content. In this work, (5 wt%) Pt/carbon nanotubes (Pt/CNT) functionalized with the [(C 6 H 2 (CH 3 ) 3 ) 2 Cu] (labeled as Pt/CNT Cu‐mes ) and [(η 6 ‐C 6 H 5 OCH 2 CH 2 OH)RuCl 2 ] 2 (labeled as Pt/CNT Ru‐dim ) organometallic complexes are implemented for electrochemical water splitting. Pt/CNT Cu‐mes shows high performance for hydrogen/oxygen evolution reaction (HER/OER), and oxygen reduction reactions, while the catalytic activity of Pt/CNT Ru‐dim is limited to HER only. Pt/CNT Cu‐mes outperformed 20% Pt/C for the HER and the OER, while sustaining a comparable behavior for the ORR, after accelerated degradation tests. Moreover, Pt/CNT Cu‐mes showed water splitting overpotential () and oxygen potential () comparable (cycle 1) and enhanced (cycle 3000) related to 20% Pt/C. Additionally, the polarization curve of a Pt/CNT Cu‐mes ||Pt/CNT Cu‐mes electrolyzer showed a higher performance and stability compared to one 20% Pt/C||20% Pt/C. The high performance of Pt/CNT Cu‐mes is ascribed to the development of Pt‐Cu alloyed phases and Cu oxides due to functionalization, which in turn led to a modification of its Pt electronic structure as confirmed by the shift of Pt 0 species and upshifting of d‐band center, and a contraction of its interplanar distance, compared to non‐alloyed Pt. Thus, Pt/CNT Cu‐mes revealed a high potential for water splitting/oxygen reactions applications.