Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
Nandini Prajapati, Hetvi Rami, Nimisha Patel
International Journal of Current Microbiology and Applied Sciences · 2023
Today, environment is polluted with waste which is not degradable. Waste placed at landfill dumping site which contain plastics account about 20% by volume of municipal solid wastes and reduce the capacity of precious landfill sites. Poly hydroxyl butyrate (PHB) which is a biodegradable and biocompatible thermoplastic compound has broadly similar physical properties to poly (propylene). It has many applications in medicine, veterinary practice, tissue engineering materials, food packaging and agriculture due to its biodegradability. In the present study, we focus on screening of bioplastics producing bacterial isolates from the soil sample from dumping site. The bacteria were characterized by their cultural characteristics, morphology and biochemical test. PHB producing bacterial isolate was further detected by using Sudan black- B staining reagent. Attempt was made to produce and extract PHB by using our bacterial isolate. Isolate exhibited significant PHB yields, thus showing a potential for further exploitation. Further analyses are currently ongoing to try to extract and characterize PHB granules.
Shivalingaiah S, Bindushree H.S, Basavaraju G.L et al.
Current Agriculture Research Journal · 2024
Soil is a vital ecosystem for various life forms, including bacteria. Bacteria are the main group of soil microbes, mostly because of their ability to produce various extracellular enzymes. Amylases are the enzymes that break down starch, which are essential in biotechnology industries such as food, fermentation, textiles, and paper manufacturing. The demand for amylase is often high since many enterprises do not have access to local supplies of the enzyme. The objective of the current investigation is to isolate and identify bacterial isolates that can produce the enzyme amylase from soil samples. Soil samples were collected from the unexplored Biligiriranga hills (11.9988° N, 77.1398° E) in south-western Karnataka Bacterial isolates were isolated from soil samples and were primarily screened on starch agar medium to determine the amylase production. Three out of fifteen bacterial isolates that produced amylase were selected based on the highest clear zone around the bacterial colony. These three bacterial isolates were identified both microscopically and biochemically. Gram staining demonstrated that the isolates are rod-shaped and gram-positive organisms. Biochemical studies indicated that the isolates were positive for the catalase and starch hydrolysis tests, whereas negative for the potassium hydroxide and methyl red tests. Besides, 16S rRNA gene amplification and sequencing confirmed the isolate as Bacillus subtilis. The 16S rRNA sequence of B. subtilis strain B has been deposited in the NCBI GenBank. The optimal growth conditions observed in B. Subtilis. The optimal growth conditions observed in B. Subtilis were 37° C temperature at pH 7 and incubation period for 37h. Thus, the isolation and identification of soil-derived amylase-producing bacteria are crucial for understanding their potential applications in various industrial processes, such as bioremediation, waste management, and the production of enzymes for food, pharmaceuticals, and biofuel industries.
Tadej ČEPELJNIK, Romana MARINŠEK-LOGAR
Acta agriculturae Slovenica · 2002
Bacteria belonging to or resembling the genus Butyrivibrio represent a significant proportion of bacterial isolates from different mammalian gastro-intestinal tracts from all over the world. The main characteristic of this genus is production of butyric acid, which has an important role in maintaining colonic health. The rumen strains – B. fibrisolvens are also known producers of conjugated linoleic acid (CLA), bacteriocins and several hydrolytic enzymes that contribute to effective forage digestion. Genus Butyrivibrio contains isolates that are very diverse in both genomic and phenotypic properties. Different researchers have proposed the grouping of isolates on the basis of some specific characteristics but up to now none was recognised as a new species. Therefore, a complex approach is needed to set basis for new species delineation and characterisations and to define a set of reasonable diagnostic methods for their discrimination.
, Joanna Fay
· 2013
Given the alternative functions of “antibiotics” as communication molecules or participants in metabolism, it seems probable that production might be influenced by factors such as nutrient availability, interactions with neighboring microbes, and/or colony or community structure and maturity. With this in mind, the present study aimed to broaden the scope of the search for novel antibiotics by experimenting with the following parameters: source of bacterial isolation, growth and assay media, and culturing techniques. Bacteria for this study were isolated from two categories of soil (petroleum-contaminated or uncontaminated) to compare diversity and antimicrobial activity. Compared to the uncontaminated soil, isolates of the petroleum-contaminated soil were as diverse and antimicrobial activity was as frequent. Antimicrobial assays were done on three different types of agar, including the standard Mueller-Hinton and two types of medium typically used for fungal growth, Yeast Peptone Dextrose (YPD) and Yeast Mold (YM). Compared to results on Mueller-Hinton, much more antimicrobial activity was seen when using YPD and YM. Finally, spent media assays were performed with pure and mixed cultures to determine if exposure to a target pathogen affects the production of antimicrobial substances by soil isolates. Those bacteria with activity against Pseudomonas aeruginosa in perpendicular streak tests were grown as mixed cultures with P. aeruginosa. In the case of Bacillus amyloliquefaciens and Pseudomonas marginalis, discs impregnated with concentrated spent media from these mixed cultures resulted in significant dose-dependent inhibition of P. aeruginosa. The same assay using pure cultures showed no inhibition.
, Patcharin Boon-eiam
· 2007
Screening of cellulase- and xylanase-producing bacteria from 40 and 45 soil samples, respectively and 10 biofertilizer samples, 51 bacterial strains were isolated (27 cellulase-producing and 24 xylanase producing strains). On the basis of their phenotypic and chemotaxonomic characteristics including phylogenetic analysis using 16S rRNA gene sequences, 7 strains were closed to Cohnella, 4 to Paenibacillus, 13 to Bacillus, 17 to Pseudomonas, 9 to Acinetobacter and 1 to Escherichia. The similarity of 16S rRNA gene sequence revealed that the cellulase-producing bacteria: PA4-1 (Group 1) was closely related to Cohnella thermotolerans CCUG 47242T (97.2%). PBS5 (Group 2), T3-3 (Group 3) and T3-2 (Group4) were closely related to Bacillus drentensis LMG 21831T (98.8%), B. megaterium IAM 13418T (88.0%) and B. cereus IAM 12605T (88.7%), respectively. N14-2 (Group 5) showed 93.0% similarity to Pseudomonas pseudoalcaligenes JCM 5968T. T6-4 (Group 6) showed 92.7% similarity to Pseudomonas nitroreducens DSM 14399T. The xylanase-producing bacteria: PT4-2 (Group 1) and PN12-3 (Group 3) showed 92.4 and 91.2% similarities to C. panacarvi KCTC 13060T, respectively. PN8-3 (Group 2) and PT6-2 (Group 4) showed 91.4 and 96.4% similarities to C. thermotolerans CCUG 47242T. PN13-1 (Group 5) and T3-2X (Group 6) showed 87.4 and 95.3% similarities to Paenibacillus agarexedens DSM 1327T. PT2-3 (Group 7) was closely related to Paenibacillus popilliae ATCC 14706T (91.8%). PN8-2 (Group 8) was closely related to B. subtilis KCTC 3135T (98.8%). PN1-2 (Group 9) was closely related to Pseudomonas aeruginosa MML 2212T (97.0%). PN9-3 (Group 10) showed 98.4% similarity to Acinetobacter baumannii ATCC 19606T. N9-2 (Group 11) was closely related to Escherichia coli KCTC 2441T (97.6%). Tested strains of Paenibacillus and Bacillus contained meso-diaminopimelic in cell wall peptidoglycan and had 7 isoprene units (MK-7) as predominant menaquinone. The DNA G+C contents of Cohnella strain were 52.3-64.9 mol%. In this study, Cohnella strain PA4-1, PT4-2, PN8-3, PN12-3 and PT6-2, Paenibacillus strain PN13-1, T3-2X and PT2-3, Bacillus strains PBS5 and T3-2, and Pseudomonas strain N14-2, T6-4 and PN1-2 were new species. However, DNA-DNA hybridization study were required to confirm their taxonomic position. Among 51 bacteria isolated, 27 cellulase-producing bacteria isolated produced cellulase 0-0.015 U/ml while the 24 xylanase-producing bacteria produced xylanase 0-0.48 U/ml. Strain PB11 produced highest endoglucanase. Optimal temperature and pH for endoglucanase activity were 60 °C, pH 7.5. Maximum endoglucanase activity was 0.11 U/ml, PA4-3 produced highest ß-glucosidase. Optimal temperature and pH for ß-glucosidase activity were 60 °C, pH 7.0. Maximum ß-glucosidase activity was 0.0091 U/ml. Optimal temperature and pH for xylanase activity were 65 °C, pH 8.0. Maximum xylanase activity was 0.51 U/ml.
Chunling Chang, Yue Guo, Kuanqiang Tang et al.
Microorganisms · 2024
The biological degradation of plant residues in the soil or on the soil surface is an integral part of the natural life cycle of annual plants and does not have adverse effects on the environment. Crop straw is characterized by a complex structure and exhibits stability and resistance to rapid microbial decomposition. In this study, we conducted a microcosm experiment to investigate the dynamic succession of the soil microbial community and the functional characteristics associated with lignocellulose-degrading pathways. Additionally, we aimed to identify lignocellulose-degrading microorganisms from the straw of three crop species prevalent in Northeast China: soybean (Glycine max Merr.), rice (Oryza sativa L.), and maize (Zea mays L.). Our findings revealed that both the type of straw and the degradation time influenced the bacterial and fungal community structure and composition. Metagenome sequencing results demonstrated that during degradation, different straw types assembled carbohydrate-active enzymes (CAZymes) and KEGG pathways in distinct manners, contributing to lignocellulose and hemicellulose degradation. Furthermore, isolation of lignocellulose-degrading microbes yielded 59 bacterial and 14 fungal strains contributing to straw degradation, with fungi generally exhibiting superior lignocellulose-degrading enzyme production compared to bacteria. Experiments were conducted to assess the potential synergistic effects of synthetic microbial communities (SynComs) comprising both fungi and bacteria. These SynComs resulted in a straw weight loss of 42% at 15 days post-inoculation, representing a 22% increase compared to conditions without any SynComs. In summary, our study provides novel ecological insights into crop straw degradation by microbes.
Karl J. Romanowicz, Z. Freedman, R. Upchurch et al.
FEMS Microbiology Ecology · 2016
Predicting the impact of environmental change on soil microbial functions requires an understanding of how environmental factors shape microbial composition. Here, we investigated the influence of environmental factors on bacterial and fungal communities across an expanse of northern hardwood forest in Michigan, USA, which spans a 500-km regional climate gradient. We quantified soil microbial community composition using high-throughput DNA sequencing on coextracted rDNA (i.e. total community) and rRNA (i.e. active community). Within both bacteria and fungi, total and active communities were compositionally distinct from one another across the regional gradient (bacteria P = 0.01; fungi P < 0.01). Taxonomically, the active community was a subset of the total community. Compositional differences between total and active communities reflected changes in the relative abundance of dominant taxa. The composition of both the total and active microbial communities varied by site across the gradient (P < 0.01) and was shaped by differences in soil moisture, pH, SOM carboxyl content, as well as C and N concentration. Our study highlights the importance of distinguishing between metabolically active microorganisms and the total community, and emphasizes that the same environmental factors shape the total and active communities of bacteria and fungi in this ecosystem.
P. Amato, M. Joly, L. Besaury et al.
PLOS ONE · 2017
Clouds are key components in Earth’s functioning. In addition of acting as obstacles to light radiations and chemical reactors, they are possible atmospheric oases for airborne microorganisms, providing water, nutrients and paths to the ground. Microbial activity was previously detected in clouds, but the microbial community that is active in situ remains unknown. Here, microbial communities in cloud water collected at puy de Dôme Mountain’s meteorological station (1465 m altitude, France) were fixed upon sampling and examined by high-throughput sequencing from DNA and RNA extracts, so as to identify active species among community members. Communities consisted of ~103−104 bacteria and archaea mL-1 and ~102−103 eukaryote cells mL-1. They appeared extremely rich, with more than 28 000 distinct species detected in bacteria and 2 600 in eukaryotes. Proteobacteria and Bacteroidetes largely dominated in bacteria, while eukaryotes were essentially distributed among Fungi, Stramenopiles and Alveolata. Within these complex communities, the active members of cloud microbiota were identified as Alpha- (Sphingomonadales, Rhodospirillales and Rhizobiales), Beta- (Burkholderiales) and Gamma-Proteobacteria (Pseudomonadales). These groups of bacteria usually classified as epiphytic are probably the best candidates for interfering with abiotic chemical processes in clouds, and the most prone to successful aerial dispersion.
J. Bradley, Christopher B. Trivedi, M. Winkel et al.
Geobiology · 2022
Glacier and ice sheet surfaces host diverse communities of microorganisms whose activity (or inactivity) influences biogeochemical cycles and ice melting. Supraglacial microbes endure various environmental extremes including resource scarcity, frequent temperature fluctuations above and below the freezing point of water, and high UV irradiance during summer followed by months of total darkness during winter. One strategy that enables microbial life to persist through environmental extremes is dormancy, which despite being prevalent among microbial communities in natural settings, has not been directly measured and quantified in glacier surface ecosystems. Here, we use a combination of metabarcoding and metatranscriptomic analyses, as well as cell‐specific activity (BONCAT) incubations to assess the diversity and activity of microbial communities from glacial surfaces in Iceland and Greenland. We also present a new ecological model for glacier microorganisms and simulate physiological state‐changes in the glacial microbial community under idealized (i) freezing, (ii) thawing, and (iii) freeze–thaw conditions. We show that a high proportion (>50%) of bacterial cells are translationally active in‐situ on snow and ice surfaces, with Actinomycetota, Pseudomonadota, and Planctomycetota dominating the total and active community compositions, and that glacier microorganisms, even when frozen, could resume translational activity within 24 h after thawing. Our data suggest that glacial microorganisms respond rapidly to dynamic and changing conditions typical of their natural environment. We deduce that the biology and biogeochemistry of glacier surfaces are shaped by processes occurring over short (i.e., daily) timescales, and thus are susceptible to change following the expected alterations to the melt‐regime of glaciers driven by climate change. A better understanding of the activity of microorganisms on glacier surfaces is critical in addressing the growing concern of climate change in Polar regions, as well as for their use as analogues to life in potentially habitable icy worlds.
Yijin Yang, Wuyao Hu, Yongjun Xia et al.
Frontiers in Microbiology · 2020
Huangjiu (Chinese rice wine) has been consumed for centuries in Asian countries and is known for its unique flavor and subtle taste. The flavor compounds of Huangjiu are derived from a wide range of sources, such as raw materials, microbial metabolic activities during fermentation, and chemical reactions that occur during aging. Of these sources, microorganisms have the greatest effect on the flavor quality of Huangjiu. To enrich the microbial diversity, Huangjiu is generally fermented under an open environment, as this increases the complexity of its microbial community and flavor compounds. Thus, understanding the formation of flavor compounds in Huangjiu will be beneficial for producing a superior flavored product. In this paper, a critical review of aspects that may affect the formation of Huangjiu flavor compounds is presented. The selection of appropriate raw materials and the improvement of fermentation technologies to promote the flavor quality of Huangjiu are discussed. In addition, the effects of microbial community composition, metabolic function of predominant microorganisms, and dynamics of microbial community on the flavor quality of Huangjiu are examined. This review thus provides a theoretical basis for manipulating the fermentation process by using selected microorganisms to improve the overall flavor quality of Huangjiu.
Tingting Deng, Linmin Wang, Tianhui Zhu
Microorganisms · 2025
Chestnut blight, caused by Cryphonectria parasitica (Murrill) M.E. Bar, is a destructive fungal disease threatening chestnut cultivation and production. In response to the limitations of chemical control, biological control using antagonistic microbes has gained increasing attention. A rhizosphere-derived bacterium, strain D39, was isolated from healthy chestnut trees and identified as Bacillus amyloliquefaciens based on morphological characteristics and the phylogenetic analysis of 16S rRNA and gyrA genes. The antifungal activity of strain D39 against C. parasitica was evaluated using dual-culture and double-layer Oxford cup assays. The strain exhibited broad-spectrum and stable antagonistic effects and harbored five key genes associated with antimicrobial compound biosynthesis (srfAA, ituC, fenD, bmyB, and bacA), as confirmed by PCR. A 145 kDa extracellular protein with strong antifungal activity was extracted and purified by ammonium sulfate precipitation, DEAE ion-exchange chromatography, and Sephadex G-75 gel filtration. LC-MS analysis identified the protein as a serine peptidase belonging to the S8 family, and its structure was predicted using multiple bioinformatic tools. In pot experiments, treatment with the strain D39 significantly reduced disease severity, achieving control efficiencies of 66.07% and 70.89% at 10 and 20 days post-inoculation, respectively. These results demonstrate that B. amyloliquefaciens D39 has strong potential as a biocontrol agent against chestnut blight, offering an effective and environmentally friendly alternative for disease management.
Zhibin Guan, Serxho Selmani, Eric Schwartz et al.
ChemRxiv · 2021
Fuel-driven dissipative supramolecular assemblies in biology, such as actin filaments and microtubules contribute to the formation of complex, dynamic structures in living organisms and give rise to emergent functions such as motility, homeostasis, self-healing, and camouflage. Several synthetic dissipative supramolecular materials have been created using chemicals or light as fuel, with the goal of furthering our understanding of biological systems and creating synthetic materials that have life-like dynamic properties. However, electrical energy, one of the most common energy sources, has remained mostly unexplored for such purposes. Here we demonstrate the use of electrically fueled dissipative assembly as a new platform for creating active supramolecular materials. Through an electrochemical redox reaction network operating in mild aqueous buffers, a transient and highly active supramolecular assembly based on a redox-sensitive cysteine derivative is achieved by applying an electric potential. The dissipative self-assembly as well as its emergent properties can be spatiotemporally controlled by modulation of electrical signals on patterned microelectrodes. Using electrical energy as a readily available and clean fuel, we are able to create dissipative supramolecular materials rapidly (in seconds to minutes) and repetitively under mild conditions with directional and spatiotemporal control. As electronic signals are the default information carriers in modern technology, the described approach offers a promising opportunity to integrate active materials into electronic devices for bioelectronics applications.
Taoran Yang, Yinghui He, Ming Yang et al.
Microorganisms · 2024
The deep ocean harbors a group of highly diversified microbes, while our understanding of the active microbes that are real contributors to the nutrient cycle remains limited. In this study, we report eukaryotic and prokaryotic communities in ~590 m and 1130 m depths using 16S and 18S rRNA Illumina reads (miTags) extracted from 15 metagenomes (MG) and 14 metatranscriptomes (MT). The metagenomic 16S miTags revealed the dominance of Gammaproteobacteria, Alphaproteobacteria, and Nitrososphaeria, while the metatranscriptomic 16S miTags were highly occupied by Gammaproteobacteria, Acidimicrobiia, and SAR324. The consistency of the active taxa between the two depths suggests the homogeneity of the functional microbial groups across the two depths. The eukaryotic microbial communities revealed by the 18S miTags of the metagenomic data are dominated by Polycystinea; however, they were almost all absent in the 18S metatranscriptomic miTags. The active eukaryotes were represented by the Arthropoda class (at 590 m depth), Dinophyceae, and Ciliophora classes. Consistent eukaryotic communities were also exhibited by the 18S miTags of the metatranscriptomic data of the two depths. In terms of biodiversity, the ACE and Shannon indices of the 590 m depth calculated using the 18S metatranscriptomic miTags were much higher than those of the 1130 m depth, while a reverse trend was shown for the indices based on the metagenomic data. Our study reports the active microbiomes functioning in the nutrient utilization and carbon cycle in the deep-sea zone, casting light on the quantification of the ecological processes occurring in the deep ocean.
Matthieu Nicault, Ali Zaiter, Stéphane Dumarcay et al.
Microorganisms · 2021
The bacteria of the genus Streptomyces and Basidiomycete fungi harbor many biosynthetic gene clusters (BGCs) that are at the origin of many bioactive molecules with medical or industrial interests. Nevertheless, most BGCs do not express in standard lab growth conditions, preventing the full metabolic potential of these organisms from being exploited. Because it generates biotic cues encountered during natural growth conditions, co-culture is a means to elicit such cryptic compounds. In this study, we explored 72 different Streptomyces-fungus interaction zones (SFIZs) generated during the co-culture of eight Streptomyces and nine fungi. Two SFIZs were selected because they showed an elicitation of anti-bacterial activity compared to mono-cultures. The study of these SFIZs showed that co-culture had a strong impact on the metabolic expression of each partner and enabled the expression of specific compounds. These results show that mimicking the biotic interactions present in this ecological niche is a promising avenue of research to explore the metabolic capacities of Streptomyces and fungi.
Sidorov Yu.G., Sidorov G. Yu., Varavin V.S.
Semiconductors · 2023
Influence of water solutions with various pH and electrochemical treatment in cathode position on concentration of charge carriers in samples Cd x Hg 1-x Te with x=0.2-0.3 is investigated. Cathodic treatment cadmium-mercury-tellurium at small density current increases concentration of donors, and at high density acceptors are formed. It is supposed that hydroxyl groups create acceptors centers, introduce in interstitial cadmium-mercury-tellurium. At treatment for a long time (it is more than 20 h) or acceptors are formed with concentration at level of 10 16 cm -3 (at high activity of hydrogen), or donors with concentration of 10 14 cm -3 (at low activity of hydrogen) are uniform distribution on all thickness of cadmium-mercurytellurium film and does not vary with the subsequent increase in time of treatment. Keywords: CdHgTe, electrochemical treatment, acceptors, activity of hydrogen.
Tecla Ciociola, Laura Giovati, Stefania Conti et al.
Microorganisms · 2021
Mycoses still represent relevant opportunistic infections worldwide, although overshadowed in recent years by other severe and more widespread infections. Moreover, deep-seated mycoses are often accompanied by unacceptably high mortality rates. Etiologic agents include endogenous components of the mycobiota, Candida and Malassezia species above all, and exogenous species, both yeasts and filamentous fungi. Old and new fungal pathogens are increasingly characterized by resistance to the existing antifungal agents, making imperative the search for effective and safe new therapeutics. Among the candidate molecules proposed in recent decades, synthetic peptides derived from the complementarity determining and constant regions of diverse antibodies (Abs), as well as the translated products of Ab-encoding genes, have proved of considerable interest. Their anti-infective activities, regardless of the specificity and isotype of the originating Ab, will be briefly presented and discussed in the light of their different mechanisms of action. Intriguing suggestions on the possible function of Abs after their half-life will be presented, following the recent detection, in human serum, of an antimicrobial Ab-derived peptide. Overall, Abs could represent a source of biologically active, highly flexible peptides, devoid of detectable toxicity, which can be easily synthesized and manipulated to be used, alone or in association with already available drugs, for new anti-infective strategies.
Toshiyuki Ohashi, Hironori Kobayashi
Batteries & Supercaps · 2025
A simple electrolyte/electrode interface using a thin film of active material in cathode is constructed to enable measurement of electrochemically active surface area (ECSA) in all‐solid‐state batteries. The correlation between specific capacitance and specific surface area at the interface is investigated. The correlation has a linear relationship and give a calibration curve. Using the calibration curve as a clue, ECSA of a composite electrode is quantitatively determined from the specific capacitance of the composite cell obtained using electrochemical impedance spectroscopy.
Kyle Diederichsen, Yayuan Liu, T. Alan Hatton
ECS Meeting Abstracts · 2022
Within the field of carbon capture, electrochemically driven methods have drawn increasing attention due to their ability to operate at ambient temperature, their efficient scaling, and potentially low energetic cost. An important consideration in such systems is the method of gas contacting to enable efficient CO 2 separation from the feed gas. Previous flow-based electrochemical processes that enable large-area gas contacting and desorption of concentrated CO 2 at a point location all utilize water as the solvent and can require significant water feeds due to high evaporation rates. Here, we demonstrate the use of liquid, redox-active sorbents in a flow system that can decouple the electrode size from gas contacting area. The concept sorbent is a nonvolatile, liquid quinone species that can be reversibly reduced and oxidized to capture and release CO 2 , respectively. In this initial study, we employ the liquid quinone with sodium salts to achieve sorbent capacities near 2.5M CO 2 and couple this sorbent to a ferrocene-derived counter electrolyte in a continuous capture – release process. Through this, we illustrate considerations in the salt choice, counter-electrolyte, and system design to best enable this concept sorbent, and discuss many opportunities for future optimizations.
Erhan Atci, Timothy Ewing, Haluk Beyenal
ECS Meeting Abstracts · 2016
Recently, some bacterial biofilms have been shown to colonize and transfer their extracellular electrons to solid electrodes in microbial fuel cells and in bioelectrochemical systems [1, 2]. This class of microorganisms is described as electrochemically active biofilms (EABs) that are able to transfer electrons outside the cell to insoluble electron acceptors (iron or metal oxides) or to solid electrodes via extracellular electron transfer [3, 4]. The need to understand the distribution of proteins involved in electron transfer in EABs is of critical importance. These proteins can be identified using mass spectroscopy (MS). It is known that there is a wide spectrum of applications in which mass spectroscopy (MS) can provide information from a sample of EABs, and these applications can easily translate to all areas of research in EABs. However, the spatial diversity of microbial functions within EABs cannot be resolved because all of the current MS analysis techniques are conducted in the bulk liquid, which provides no spatial resolution with respect to the structure of EABs. Separation techniques can be combined with MS to present a more focused data set with regard to composition; however, MS analysis still lacks the capacity to investigate variation with depth of EABs. Depth profiles will have the potential to elucidate the mechanisms of the surrounding matrix and the roles of the microorganism with respect to the layers of EABs and the growth interface. To date, this MS technique has not been used for depth profiling in EABs. This is mostly because there was no tool available to extract samples from different depths in EABs. Microcapillaries with a several-micrometer tip diameter can be used in EABs without damaging its structure for the depth profiling of selected chemicals. The goal of this work was to develop a microcapillary system which can extract samples at desired depth inside the EABs. Ambient pressure surface ionization mass spectrometry is used to obtain a chemical analyte for sampling from interfaces without special sample preparation [5]. Desorption electrospray ionization (DESI) is an ambient ionization technique in which charged droplets from an electrosonic spray ionization source are aimed towards a surface with a proximal atmospheric pressure mass spectrometer inlet. In this technique, analyte molecules are collected from flat surfaces followed by ionization using a self-aspirating nanoelectrospray. This technique directly transports and ionizes an analyte that is desorbed from a surface into a liquid and it is called as nanospray DESI (nano-DESI). The nanospray capillary transports the charged liquid to the mass spectrometer inlet directly, eliminating splashing while minimizing analyte transport distance. The target application of the developed microcapillary system is to interface it with a nano-DESI sensor which can be used to characterize in situ , depth-resolved analyses of metabolites and possibly proteins. The developed nano-DESI sensor is composed of two microcapillaries placed in an outer case made of glass. Figure 1 shows an image of a developed nano-DESI sensor. In this system, the solvent delivery and its collection were made from the same microcapillaries. We managed to operate the sensor between 10 nL/min and 100 mL/min flow rates. After optimization of the flow rates, we tested it in EABs. EABs were grown according to our previously published paper and book [6, 7]. While we had succeeded in developing a nano-DESI sensor, we found unexpected challenges using it with EABs. Finally, the microcapillary system developed for this work enabled us to use it for quantifying electron transfer processes in EABs [7]. References: 1. Hamelers, H.M., et al., New applications and performance of bioelectrochemical systems. Applied Microbiology and Biotechnology, 2010. 85 (6): p. 1673-1685. 2. Logan, B.E., Exoelectrogenic bacteria that power microbial fuel cells. Nat Rev Micro, 2009. 7 (5): p. 375-381. 3. Lovley, D.R., Microbial fuel cells: novel microbial physiologies and engineering approaches. Current Opinion in Biotechnology, 2006. 17 (3): p. 327-332. 4. Logan, B.E., et al., Microbial Fuel Cells: Methodology and Technology†. Environmental Science & Technology, 2006. 40 (17): p. 5181-5192. 5. Roach, P.J., J. Laskin, and A. Laskin, Nanospray desorption electrospray ionization: an ambient method for liquid-extraction surface sampling in mass spectrometry. Analyst, 2010. 135 (9): p. 2233-2236. 6. Lewandowski, Z. and H. Beyenal, Fundamentals of Biofilm Research, Second Edition . 2014: Taylor & Francis. 7. Babauta, J.T. and H. Beyenal, Local Current Variation by Depth in Geobacter Sulfurreducens Biofilms. Journal of The Electrochemical Society, 2014. 161 (13): p. H3070-H3075. Figure 1
Ariel Friedman, Lior Elbaz
ECS Meeting Abstracts · 2024
The development of platinum group metal-free catalysts is considered the most prominent path for reducing the cost of low-temperature fuel cells (LTFC). Despite the great advancement in the field, its further progress is currently limited by the ability to understand and mitigate the catalysts’ degradation mechanisms, which up to recent years was limited by the lack of activity descriptors. Recent work showed that this could be solved using Fourier-transformed alternating current voltammetry that enables to deconvolute Faradaic currents arising from the redox reaction of the active sites from the capacitive currents, and by that accurately measure the electrochemically active site density of these catalysts in situ fuel cells. However, the analysis of the results can be complex, requiring simulation software for accurate parameter extraction. Herein, a simplified analysis of Fourier-transformed alternating current voltammetry is presented. This was done by mapping the influence of various variables, such as resistivity, capacitance, and thermodynamic and kinetic dispersion, on the accuracy of electrochemically active site density measurements. Under specific, yet realistic, operating conditions, a single equation with the peak current of the 5th harmonic as the only variable can be used to quantify electrochemically active site density with high accuracy. This approach was demonstrated using molecular catalysts, iron phthalocyanine, as a model molecule, and a commercial, heat-treated catalyst.
Pavithra Bhakthi Jayathilaka, Athula Bandara, Nadeeshani Nanayakkara et al.
Research Square · 2023
Abstract Anode material plays big role in electrochemical oxidation process of water treatment. Since its coating composition can affect the degradation path way, the reaction mechanism and the efficiency of electrochemical oxidation process, it is important to identify the optimum conditions of a given material composition of a high electrochemical active area. In this work, central composite design with response surface method was implemented to optimize Ir and Sb contents of Ti/IrO 2 -Sb 2 O 3 anode. In order to do that, response factors (i.e. anodic charge and open circuit potential value), which are related to electrochemically active area of the anode were monitored. They were expressed in second-order functions of two factors such as Ir and Sb concentrations. Since these factors showed significant impact on anodic charge and open circuit potential values of the anode, statistical analysis was done in order to gain the understanding of them. ANOVA table results, R 2 and R adj values, lack of fit test and p values indicated that the models represent experimental data well. 3-D response surface and 2-D contour plots visualized the effects. Overall analysis of results found that 0.3625 mC anodic charge value and -0.0869 mV open circuit value can be obtained by optimum material conditions of 0.08 g/L and 0.92 g/L Ir and Sb concentrations respectively.
G-S Park, HS Kim, SG Doo
Microscopy and Microanalysis · 2006
Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005
Soyoung Joo, Heon-Cheol Shin
ECS Meeting Abstracts · 2024
All-solid-state batteries (ASSBs) are currently receiving much attention as one of the most promising next-generation rechargeable battery systems due to their promise of high energy density and high safety. Despite many efforts to commercialize ASSBs, however, there are still many unresolved technical challenges. Unlike conventional lithium-ion batteries (LIBs), the interface between the cathode and electrolyte in ASSBs exhibits a complex degradation pattern that combines chemical and mechanical degradations. In particular, the high Ni content cathode materials in ASSBs are commonly known to suffer from significant additional degradation mechanism, e.g., volume expansion/contraction due to H2-H3 phase transitions at high voltages, resulting in particle cracking. This degradation of the integrity of the active material leads to a reduction in electrochemically active surface area (active area afterward) due to loss of contact between the active material and solid electrolyte, slow diffusion rate of lithium in the active material, and isolation of the active material. These issues are recognized as major contributors to cell performance degradation. Among these issues, the changes in the active area have a decisive impact on the rate of redox reactions that are key to battery charging and discharging kinetics, so accurate determination of the active area is crucial for the diagnosis and improvement of batteries. In the electrochemical analysis of ASSBs, the poor contact between the solid electrolyte and the active material, or the change of the contact properties during the battery operation, should be a very important consideration. Especially when determining kinetic factors such as charge transfer resistance and chemical diffusion coefficient of cathode material by electrochemical methods, the models we usually use include the electrode surface area value as an important variable, so the accurate estimation of the active area is indispensable for obtaining reliable electrochemical properties. Unlike typical LIBs, in ASSBs the active material/electrolyte interface contact properties change relatively significantly during repeated cycling, so devising a reliable technique to analyze the active area of active materials in ASSBs is very crucial for the research and development of ASSBs. However, to the best of our knowledge, there are still very few studies on this. In this study, we propose promising methods to measure the contact characteristics between the cathode material and the solid electrolyte in ASSBs, namely the electrochemically active surface area, and discuss their reliability based on intercomparison and literature reports. For this purpose, first, the method for determining the active area of active materials based on galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) reported in conventional LIBs was reviewed. Then, its applicability to ASSBs was explored, and a way to improve the reliability of the analysis was proposed. Specifically, a three-electrode cathode half-cell experiment was conducted to analyze the active area of the Ni-rich cathode. The active area was calculated by comparing the diffusion coefficient measured by EIS with that obtained by GITT. When comparing the active area determined at different voltages, it was observed that the active area varies significantly with voltage most likely due to the volume change caused by the H2-H3 phase transition. The second electrochemical method performed for the determination of the active area of the active material is based on the quantification of the lithium intercalation sites on the cathode surface based on the analysis of the frequency factor in Arrhenius expression. For this purpose, battery at different charge states were kept at high temperatures for long periods of time to induce interfacial degradation. The temperature-dependent charge transfer resistance was then determined by EIS analysis, which was used to interpret the redox (or lithium absorption/desorption) reactions kinetically. The experimental results showed that the redox reaction rate followed exactly the Arrhenius relationship for all the charge states used, but the activation energies and frequency factors changed differently depending on the charge state. In this study, we discuss these results in relation to various phenomena that may occur during high-temperature aging, such as the formation of rock salt structures and cracks on the nickel-rich cathode surface, and try to estimate the change in active area. In this study, the electrochemical analysis methods of the contact characteristics between the cathode and the solid electrolyte in ASSBs will be examined in depth and their reliability will be assessed. In addition, further improvements in active area analysis techniques for active materials in ASSBs will be discussed.
Viktor Čolić
· 2024
Additively manufactured (AM) nickel electrodes offer a great potential as an efficient solution for oxygen evolution catalysts in alkaline electrolyzers, since advanced fabrication methods allow the design of high surface area electrodes. The accurate determination of the electrochemical active surface area (ECSA) is a key step in the evaluation of the intrinsic catalytic activity of complex electrodes. In this work, we fabricated Ni electrodes with different macroscopic lattice structures using laser powder bed fusion of metals (PBF-LB/M). The selected designs allow exploring the effects of the electrode geometry on the electrochemical performance. X-ray photon spectroscopy (XPS) and a non-contact optical profilometer (NCOP) were used to investigate the composition and surface morphology of the electrodes. The ECSA was determined by three different approaches. 1. Linear and non-linear allometric fitting of the double layer capacitance from voltammetric experiments. 2. Integration of the Ni2+/Ni3+ transition, also from voltammetry. 3. Assessing double layer capacitance determined from electrochemical impedance spectroscopy (EIS) at open circuit potential (OCP) and the adsorption capacitance for the oxygen evolution reaction (OER) intermediates. Comparing these methods, large deviations in the resulting ECSAs were found, motivating a comprehensive discussion. In addition, four different reactions were investigated, ferri-ferrocyanide redox system, hydrogen evolution, ethanol electrooxidation, and oxygen evolution reaction. The obtained results demonstrate the potential of AM to tailor electrode performance by altering electrode geometry. The findings underline the importance of the ECSA determination for the comparison of the electrocatalytic activity in different electrodes.
Shokaku Kim, Kouhei Shimada, Yohei Okada et al.
ECS Meeting Abstracts · 2014
Crosslinking reaction is a valuable method for the integration of two or more functionalities or properties to facilitate the effective design and fabrication of bioconjugates and nanomaterials. In particular, crosslinking reactions using photoactive linkers or click-chemistry for fluorescent labeling offer versatile strategies to manufacture biomolecular probes, which allow surface modification through stable covalent bonds. Although electroorganic synthetic methods have produced a wide variety of useful intermediate species under mild conditions, their application to practical crosslinking is restricted due to the difficulty of mass transfer, i.e., the unstable reactive intermediate generated from the electrode must be transported to another location. To date, attempts in solid-phase electroorganic synthesis have been limited mostly to immobilization of substrates on an electrode or indirect electroorganic synthesis. Furthermore, solid-phase syntheses often require excess amounts of reagents to complete target reactions due to low reactivity, and typical electroorganic approaches therefore suffer from in situ generation of unstable intermediates trapped within the solid-supports. Therefore, the development of electrochemically active crosslinkers for the modification of insoluble targets, nonconductive samples, and biomolecules remains a significant challenge. We have recently accomplished intermolecular carbon-carbon bond formation reactions with aliphatic alkenes via anodically generated cation intermediates to afford a variety of polycyclic systems. Furthermore, less reactive alkenes could be coupled with electrochemically activated substrates, which can be trapped in a thermomorphic solution-phase, spatially separated from the electrode, by using cyclohexane-nitromethane as a medium. These solution-phase reaction systems effectively accelerated intermolecular interactions between the less reactive olefins and unstable cation intermediates. We hypothesized that this approach would allow selective, direct and stable modification of alkene-attached insoluble targets with electrochemically active species. The electrochemically active crosslinking system could also enable the construction of a fluorescent probe, triggered by the formation of a covalent linkage. This strategy addresses the time-consuming, multistep post-processing problems associated with fluorescent labeling, such as washing and purification, and reduces false signals arising from nonspecific adsorption of a fluorophore or its undesired cleavage in the detection environment. To study the selectivity of the functional groups in this reaction system, electrochemical coupling reactions were conducted using phenol 1 in the presence of terminal mono-substituted olefins and trialkyl-substituted olefin 2 (Table1). These results indicate that the phenoxonium cations anodically generated in the LiClO 4 -MeNO 2 reaction system can be selectively trapped with trialkyl-substituted olefins to afford the cycloadduct as a fluorescent unit in high yields. Based on these results, we also attempted to synthesize a fluorescent probe composed of 2,7-dimethyl-6-octenoic acidon amino-modified silica and unactivated alkenes to confirm the lifetime of the phenoxonium cation. The size of the amino-silica particles was ca. 0.6-0.7 μm and the amino group content was 0.4 mmol/g. After the reaction, the mixture was washed in water and collected by filtration. Fluorescence on the silica was observed by fluorescent microscopy. The reactive site of the alkenes cannot approach the electrode because the silica molecule is too large, and thus, it was assumed that the phenoxonium cation was stable until reacting on the silica surface. In conclusion, an electrochemically active crosslinking reaction was developed to attach fluorescent probes to aliphatic alkenes. Several dihydrobenzofuran derivatives formed via [3+2] cyclization reactions exhibited fluorescence properties. Furthermore, this approach allows the effective and stable modification of alkene-attached silica gel as an insoluble target with electrochemically active species, which enables the construction of fluorescent probes, triggered by the formation of a covalent linkage. References Shokaku Kim, Kumi Hirose, Jumpei Uematsu, Yuzuru Mikami, Kazuhiro Chiba, Chem. Eur. J. , 2012 , 18(20) , 6284-6288.
Gregory Su
ECS Meeting Abstracts · 2021
The performance of electrochemically active materials, for example, ion-conducting polymer membranes, is defined by their unique molecular architecture and resulting hierarchical morphology across length scales that controls functional properties such as transport. Synchrotron X-ray probes have proven invaluable to reveal details into the chemistry and structure of electrochemical systems. Nevertheless, opportunities remain to uncover new structure-property insights with emerging synchrotron tools. Energy-resolved X-ray absorption spectroscopy coupled with resonant X-ray scattering can elucidate morphology with chemical sensitivity in heterogeneous polymer-based systems. These techniques are amenable to in situ and operando studies. Moreover, they are well-suited to probe thin films, enabling detailed interrogation of relevant interfaces, for example, membrane-electrode interfaces, and how interfacial molecular assembly impacts charge transport and overall electrochemical performance. Herein, we present examples of polymer morphology evolution, including perfluorinated ionomers with unique side chain architectures, leveraging the sensitivity of energy-resolved scattering to reveal detailed aspects of membrane phase separation. These studies highlight opportunities in synchrotron-based resonant scattering coupled with spectroscopy and other techniques to achieve new insights into the bulk and interfacial structure of membranes and other complex electrochemical materials.
Abinaya Kamaraj, Johann Wilhelm Erning, Stefan Reimann et al.
CORROSION 2019 · 2019
Abstract The generation of active disinfectants by electrochemical processes gains market share due to the lack of need for transportation and storage of dangerous goods as well as the ease of operation. Usually, the process involves the use of specific electrodes for electrolysis of water to produce active chlorine species, sometimes supported by the addition of chlorides to the process water. Thus, the influence on the corrosion behavior can vary widely. The susceptibility of AISI 304 stainless steel to crevice corrosion on the effect of contact with electrochemically active fluids was investigated using exposure and stepwise potentiostatic polarisation. Crevice materials made up of 304 SS and Polyether ether ketone (PEEK) forming two kinds of crevices including 304 SS-to-PEEK and 304 SS-to-304 SS were tested, and results indicate that 304 SS specimen is strongly susceptible to crevice corrosion in 304 SS crevice former assembly. The combination of the influence of oxidant and chloride concentration were examined in detail, and results indicate a strong influence of free chlorine and chloride concentration to crevice corrosion. The corroded surface morphology was investigated using scanning electron microscope(SEM), Energy Dispersive X-ray (EDX) and Confocal microscope.
Vitor Silva Liduino, Magali Christe Cammarota, Eliana Flávia Camporese Sérvulo
LatinCORR 2023 · 2023
Electroactive biofilms provide environments conducive to the occurrence of microbiologically influenced corrosion (MIC) in several industrial sectors. There are many distinct MIC mechanisms associated with different microbial groups and metabolism types. Most published research studies on MIC focus on bacteria, where sulfate-reducing bacteria (SRB) have the largest impact on corrosion because sulfate is widely distributed in anoxic environments, such as offshore oil reservoirs. This study investigated the role of an oilfield SRB-consortium in the AISI 1020 carbon steel corrosion immersed in hypersaline seawater (10% NaCl w/m) with low dissolved oxygen (&gt;2 mg/L). This steel is globally used to build oil and gas industry facilities exposed to both onshore and offshore sites due to its low cost and good corrosion resistance. Each microcosm consisted of 100 mL seawater and one suspended metallic coupon of 6 cm2 total surface area. Three identical microcosms were performed. Simultaneously, abiotic control assays without microbial consortium were also executed. The assays were analysed by weight loss method and scanning electron microscopy (SEM) after 10 days at 40°C. Additionally, SRB counts in the hypersaline seawater at diferent times are done. The planktonic population increased slow and its peak at 9.5× 106 MPN/mL appeared at day 10. This result suggest that the increased salt content was not an inhibiting factor since the SRB consortia grew well and remained metabolically active throughout the assay. Corrosion rates are shown in Table 1. The abiotic condition must have improved the corrosion rate because of the large amount of chloride ions (Cl−) in the hypersaline seawater (10% w/v salinity). Cl− enhances the electrical conductivity of aqueous solutions and consequently boosts the velocity of oxidation and reduction reactions of the corrosive process. Thus, it proceeds an homogeneous degradation over the entire surface area causing signifcant mass loss and well-proportioned corrosion rate. On the other hand, SRB-MIC consumes only a relatively small amount (mass) of material due to the localized corrosion (pits), corroborating the low corrosion rate. Many pits were detected in the steel surface with a maximum depth of 33 μm; it was 86% deeper than the maximum pit depth in abiotic condition.
Ana Sanz Matias, Fabrice Roncoroni, Siddharth Sundararaman et al.
Research Square · 2023
Abstract Divalent ions, such as Mg, Ca, and Zn, are being considered as competitive, safe, and earth-abundant alternatives to Li-ion electrochemistry. However, the challenge remains to match elec- trode and electrolyte materials that stably cycle with these new formulations, based primarily on controlling interfacial phenomena. We explore the formation of electroactive species in the electrolyte Ca(BH 4 ) 2 in THF through molecular dynamics simulation. Free-energy analysis indicates that this electrolyte has a majority population of neutral Ca dimers and monomers, albeit with diverse molecular conformations as revealed by unsupervised learning techniques, but with an order of magnitude lower concentration of possibly electroactive charged species, such as the monocation, CaBH 4 + , which we show is produced via disproportionation of neutral Ca(BH 4 ) 2 complexes. Dense layering of THF molecules within 1 nm of the electrode surface (modeled here using graphite) hinders the approach of reducible species to within 0.6 nm and instead enhances the local concentration of species in a narrow intermediate-density layer from 0.7-0.9 nm. A dramatic increase in the monocation population in this intermediate layer is induced at negative bias, supplied by local dimer disproportionation. We see no evidence to support any functional role of fully-solvated Ca 2+ in the electrochemical activity of this electrolyte. The consequences for performance and alternative formulations are discussed in light of this molecular-scale insight.
Shoji Hall
ECS Meeting Abstracts · 2020
The conversion of O2 to H2O is an important fuel cell reaction for the recovery of renewable electricity from chemical fuels. Alloys of Pt-group metals (PGMs) with transition metals have emerged as catalysts with enhanced activity and durability for the oxygen reduction reaction (ORR). To date, most studies focus exclusively on alloys that adopt a Face-centered cubic (FCC) or Face-centered tetragonal (FCT) crystal lattice. Under ORR operating conditions, these materials evolve from alloys to Pt core-alloy shell materials, in this case both the alloy core and Pt shell retains the CCP type crystal structure; indicating that materials can dynamically change during catalysis. Here we present the synthesis of Pd-Bi based ordered intermetallics by partial dealloying of a Bi rich alloy. We found that under ORR operation conditions, ß-PdBi2 which adopts a tetragonal lattice, transforms to Pd3B orthorhombic crystal structure; this transformation is mediated by oxidative Bi corrosion under potential cycling, and reconstruction of the atoms in the bulk. To the best of our knowledge, this is the first report of a material that exhibits an electrochemically driven, non-congruent phase transition among materials with different crystal structures. The resulting phase-converted Pd3Bi is stable and exhibits high performance for ORR. Phase-converted Pd3Bi outperform Pt and Pd metal, reaching mass activities of 2.6 A/mgPd, which is nearly 10X higher than Pt/C (~0.3 A/mgPt) and Pd/C (~0.2 A/mg) at 0.9 V vs the Real Hydrogen Electrode (RHE). The mass activity of Pd3Bi decreases by ~38% after 10,000 cycles, indicating that it is stable. Activation energy (Ea) determined by temperature dependent electro-kinetic measurements indicates that the activity enhancement on phase-converted Pd3Bi originates from anion-poisoning resistant behavior. These results establish that PGMs-based ordered intermetallics with low-symmetry crystal structures can be highly active and durable electrocatalysts.
Dina Fattakhova, Petr Krtil
MRS Proceedings · 2001
ABSTRACT Nanocrystalline Li-Ti-O spinel samples were prepared by solvothermal reaction of TiO 2 with lithium hydroxide in water and ethanol. The hydrothermal reaction proceeds at temperature higher than 130 °C. The reaction proceeds via dissolution-precipitation mechanism and its course is not sensitive to titanium dioxide polymorph used in the reaction. Product of the reaction in water has cubic rock salt type structure. It converts, however, to spinel if annealed to temperatures exceeding 250 °C. The re-crystallization is accompanied with water removal from the structure. Solvothermal reaction in ethanol leads directly to a product with spinel structure without need for annealing. Both products are active for Li insertion; theelectrochemical activity. The specific capacity ranges between 100 and 160 mAh/g depending on the annealing temperature.
Haluk Beyenal, Jerome T. Babauta
ECS Meeting Abstracts · 2016
Almost a decade has passed since the rediscovery of microbial fuel cell research, yet the power generation of these devices has not advanced. This is mainly due to the research being focused solely on the improvement of power generation rather than on a fundamental understanding of electron transfer processes and their limitations in the biofilms grown on the anode and cathode. The chemical and electrochemical gradients in these biofilms play a critical role in electron transfer rates between cells and a solid electron acceptor or donor. Our research group has developed and used novel microelectrodes and in situ Nuclear Magnetic Resonance (NMR) imaging techniques to investigate electron transfer mechanisms in biofilms. The newly developed microelectrodes were successfully operated on polarized surfaces. Both NMR and microelectrode technologies allowed us to quantify metabolic and chemical variations in biofilms while the cells respired on polarized electrode surfaces. We combined our techniques with two new techniques – rotating disk electrode (RDE) and electrochemical quartz crystal balance (eQCM). The addition of both these techniques allowed us to differentiate mass transfer limitations from intra-biofilm electron transfer processes. When we attempted to identify limitations in anodic biofilms, first, we addressed the importance of local acetate concentrations within G. sulfurreducens biofilms using a novel acetate microelectrode which has better resolution than NMR. The microelectrode work confirmed our previous NMR findings and generated profiles on the order of µM. We should note that the microelectrode method developed is significantly more economical to use than NMR and can facilitate rapid in situ measurements of acetate in anoxic biofilms. Second, we integrated our previous RDE method with our eQCM methods to show that, on both a per current basis and a per mass basis, biofilm capacitance is a better indicator of biofilm performance than conductance.In particular, we compared the capacitance/conductance relationship of G. sulfurreducens biofilms to those of both polyaniline films and diffusing flavin systems. The results indicated that the tandem increase in capacitance and conductance is unique to the extracellular electron transfer mechanisms operating in G. sulfurreducens biofilms. Our local potential and current measurements indicated that the upper layers of the biofilms are always under a reducing condition. This knowledge also confirmed that the amount of cytochromes in the biofilm is not high enough or the biofilm conductivity is not sufficient to generate an oxidizing condition near the top of a biofilm. Finally, we extended the role of excess surface area in the scale-up of bioelectrochemical systems by examining biomass accumulation under this condition. We found that biomass continues to accumulate on the excess surface area electrodes with net arithmetic growth rates and acetate consumption during steady-state current. The linear growth rates constrained by ion transport limitations that we found may be important factors in understanding the current generation using high-surface-area 3D electrodes with advection. In conclusion, we demonstrated the importance of the metabolic inactivity of layers within G. sulfurreducens biofilms using microelectrodes and NMR. In addition, we verified these findings using electrochemical impedance spectroscopy (EIS) by demonstrating the pseudocapacitive behavior of biofilm impedance. We also demonstrated the feasibility of directly measuring biofilm inefficiencies via intra-biofilm electron transfer rates and local current depth profiles.
Haisheng Fang, Liping Li, Guangshe Li
Chemistry Letters · 2007
Abstract Highly crystalline olivine-structured LiMnPO4 was prepared by a simple hydrothermal method in a basic aqueous medium at 200 °C for 10 h. The particle shape of the as-prepared LiMnPO4 was plate-like with the thickness of 100–200 nm. A capacity of 68 mA h g−1 was reversibly achieved between 3 and 4.5 V vs. Li+/Li.
Po-Chun Hsu
Advanced Photonics Congress 2024 · 2024
The combination of reversible electrochemical reaction and metasurface allows multifunctional and multispectral light and heat management. This talk will introduce two examples, conjugated polymers and metal, and the design principle to accomplish various dynamic thermoregulation applications. Full-text article not available; see video presentation
, Chatthai Kaewtong
· 2007
Hexahomotriaza-p-chlorocalix[3]arene (L1) was successfully by synthesized and functionalized to provide two novel heteroditopic sensors. From complexation studies, the hexahomotriaza-p-chlorocalix[3]arene could be used as a selective chromogenic sensor for F[superscript -] and H[subscript 2]PO[subscript 4][superscript -]. The partial-cone hexahomotriaza-p-chlorocalix[3]-trinaphthylamide (L2) synthesized from both cone and partial cone triester derivatives exhibited a selective fluorescent sensor for Cd[superscript 2+], Pb[superscript 2+] and F[superscript -]. Hexahomotriaza-p-chlorocalix[3]-cryptand (L3) which is fixed in cone conformation and possesses a close well-defined cavity showed a high selectivity for Cl[superscript -] ion. Tuning this ligand by complexing with Zn[superscript 2+] on hexahomotriaza-p-chlorocalix[3]arene framework, its anion binding selectivity changed to Br[superscript -] ion. Moreover, a new class of chemosensor recognition elements based on conjugated polymer network ultra-thin films from electrochemical cross-linking of hexahomotriaza-p-chlorocalix[3]arene-carbazole (L4) was successfully realized. Its demonstrated high selectivity and sensitivity towards Zn[superscript 2+] was observed. A self-assembly between polyamidoamine (PAMAM) dendrimer and dendron surfmers (G[subscript 0]COOH, G[subscript 1]COOH and G[subscript 1]COOH) was prepared through an efficient supramolecular interaction. The electrochemical cross-linking of dendrimer complexes (PAMAM-G[subscript 1]COOH) provided thin films which have a ring-like or donut structure most likely composed of the PAMAM-core and dendron-carbazole shell. In addition, [pi]-conjugated dendrimer-protected gold nanoparticles in a stable colloidal form have been successfully prepared via simultaneous reduction of AuCl[subscript 3] with terthiophene (PT) and carbazole (PC) peripheral functionalized PAMAM dendrimers.
V. N. Nwigwe, B. O. Uba
Journal of Applied Sciences and Environmental Management · 2022
In this study, piggery and poultry wastewaters were used as agro-based industrial wastewaters to evaluate the role of electrochemically active bacteria in an anodic chamber of microbial fuel cell (MFC) with 0.1M potassium permanganate cathodic cell using salt bridge preparation. The BOD5, COD, TDS, TSS, nitrogen, phosphates, pH and conductivity served as indicative parameters for determining the wastewater treatment efficiencies (WWTE) of the MFCs. Results obtained from the WWTE reveal that the MFCs were able to reduce the piggery wastewater parameters, BOD, COD, TDS, TSS, nitrogen, phosphate, pH, conductivity by 89.66, 69.57, 52.20, 69.04, 70.27, 59.57, - 4.41 and 0.99 %, respectively while the same parameters for the poultry wastewater were reduced by 82.61, 78.59, 58.03, 67.13, 70.49, 64.52, 2.70 and 28.04 %, respectively. Statistically, there were significant differences before and after treatments and between wastewater samples revealing that that the effect of treatment before and after on physicochemical parameters were different for piggery wastewater than they were for poultry wastewater. Microbes in the biofilms on the electrodes (potential exoelectrogens) include Staphylococcus aureus, Bacillus cereus, Micrococcus luteus, Corynebacterium sp., Enterococcus sp., Pseudomonas aeruginosa, Escherichia coli, Klebsiella sp., Salmonella sp. and Shigella sp. while the fungal isolates include Mucor sp., Saccharomyces sp. and Aspergillus sp. in both piggery and poultry wastewaters. Thus, microbial fuel cell bacteria oxidize the organic matter leading to decontamination of the wastewater – a significant approach in addressing the public health threats of these wastes in our country.
Kaitlyn Dwelle, Adam Willard
ChemRxiv · 2019
This manuscript presents a theoretical model for simulating molecular dynamics at electrode-electrolyte interfaces. The novelty of the model is that it combines a method for simulating constant potential electrodes and a method for simulating stochastic interfacial charge transfer. We combine these methods to simulate model electrochemical systems under driven conditions, where charge is flowing across the electrode-electrolyte interface. The manuscript describes the theoretical formalism and applies it to a model battery system. We highlight the ability of the model to support the formation of electrical double-layers and to provide microscopic physical insight the results of potential jump experiments.
, Jutatip Kongpeth
· 2013
DNA sensors are useful in various applications including medical diagnosis, environmental monitoring, food quality control, and forensic science. The sensor usually consists of a sensing element known as a “probe” that can bind specifically with the DNA target. The binding between the probe and the target creates a should allow rapid detection, provide high specificity and sensitivity, require small sample volumes and require low cost instrumentation. Electrochemical DN sensors are one type of DNA sensors that meet all the above requirements. Peptide nucleic acid or PNA is a unique DNA analogue that is often employed as the sensing element in DNA sensors due to its superior affinity and specificity in recognition of DNA than natural DNA or other DNA analogues. To combine the advantages of PNA and electrochemistry in DNA sensing, an electrochemical DNA sensor based on pyrrolidinyl peptide nucleic acid (acpcPNA) probe that does not require probe immobilization was developed. Various kinds of redox-active redox reporters including anthraquinone and methylene blue were synthesized and introduced onto acpcPNA via acylation chemistry. The redox-active acpcPNA were purified by reverse phase HPLC and characterized by MALDI – TOF MS. The labeled acpcPNA formed hybrids to DNA with high thermal stability and specificity according to UV melting experiments. The immobilization-free electrochemical DNA detection platform was next developed on an inexpensive screen-printed carbon electrode (SPCE) by using a square-wave voltammetric (SWV) technique. Electrostatic interactions between the acpcPNA probe, the acpcPNA hybrid and the electrode surface modulate the electron transfer between the labeled acpcPNA probe and the electrode, providing the basis of the signal transduction. As an example, a highly specific signal-on detection of DNA by SWV with LOD and LOQ in the low nanomolar range was achieved using anthraquinone-labeled acpcPNA probes on PQDMAEMA-modified SPCE electrodes. Applications of the technique for analysis of real DNA samples that had been amplified by LAMP or PCR were demonstrated. Furthermore, the effects of the charges on the surface of the electrode and on the acpcPNA probe were studied to obtain further insights into the mechanism of the signal transduction. Accordingly, a novel and highly promising immobilization-free electrochemical DNA sensor based on redox-active acpcPNA prode on SPCE was successfully developed.
Gang Fan
ECS Meeting Abstracts · 2024
Bacteria produce a variety of soft materials, but they are limited in their structure and function. A synthetic system in which the power of bacterial engineering is combined with traditional organometallic catalysis could pave new avenues to polymer synthesis. Here we demonstrate that the electroactive bacteria Shewanella oneidensis can control the activity of a transitional-metal catalyst in atom-transfer radical polymerization (ATRP) through extracellular electron transport (EET) machinery. This polymerization features characteristics of controlled radical polymerization, such as first-order kinetics, narrow molecular weight distribution and block-polymer synthesis. Catalyst performance and polymer microstructure were a strong function of bacterial metabolism, specific electron transport machinery, and catalyst design. Moreover, different bio-renewable and bio-friendly energy sources, such as lactate, glucose, pyruvate and xylose, could be utilized to control the rate of polymerization process. Overall, our results demonstrate that targeting biological electron transport pathways may combine the advantages of metabolic engineering with traditional polymer synthesis.
Fitria Nur Laily, Sri Rachmania Juliastuti, Raden Darmawan
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences · 2024
Microbial Fuel Cell (MFC) are the one of utilization of waste for renewable energy continues to be developed. According to the FAO, 32% of all food for human consumption is discarded about 1.3 billion tonnes per year. In this study, Microbial Fuel Cells used an organic source in the form of food waste that had been hydrolyzed by Aspergillus oryzae, Aspergillus aculeatus, and Candida rugosa. The results of the hydrolysis are entered into the MFC system. In the MFC system it is mixed with Sidoarjo mud and Shewanella oneidensis MR-1, then put into a Single Chamber microbial fuel cell (SC-MFC) to generate electricity. In this research, also added micronutrients (Mg2+, Ni2+, Cu2+, Ca2+, Pb2+, Co2+, Cd2+, Cr2+, and Zn2+) to increase the metabolic of Shewanella oneidensis MR-1 bacteria, so can elevate electric currents. electrons and protons are produced by microorganisms by changing organic compounds in the substrate. The results showed that the best power density was 6.652 W/m2 with BOD 89.362% and COD removal 77.273% achieved with a ratio of food waste to water of 2:1 M. Food hydrolysis is capable of hydrolyzing 40% food waste into glucose within 24 hours. The greatest percentage of glucose decreased was achieved by Cobalt micronutrient addition with 77% of glucose decreased. Therefore, MFC can be greatly enhance food waste degradation to become a carbon source in a microbial fuel cell for electricity production.