V. Iosifov, A. Melikov, A. I. Matveev et al.

IOP Conference Series: Earth and Environmental Science • 2022

Of the widely used types of water purification its disinfection by the method of electric activation makes it possible to cleanse bacteria, spores, fungi of microorganisms due to the electrical effect of the directional deviation of the electrons activity in the aquatic environment from the equilibrium state and reduces toxicity due to highly active reducing agents. When using of the electrically activated water for irrigation, an increase in the energy of germination and plants germination ability is observed. Supply of electric activated water by droplet outlets is fraught with relaxation of the water mass state due to the long time it takes for the liquid to pass from the electric activation unit to the plant. To minimize this time, the authors propose to organize an autonomous supply of the water electrical activation process used for irrigation. The paper proposes a new water electric activation method, which differs from the existing ones in that the energy for the installation of electrochemical activation is generated due to the movement of water masses. It is expected that, in practice, the water electric activation by part of the kinetic energy concentrated in its flow will help to minimize losses in the supplying process to irrigated crops, which will significantly increase their yield.

A. Borges, K. Kostov, R. Pessoa et al.

Applied Sciences • 2021

Plasma is an electrically conducting medium that responds to electric and magnetic fields. It consists of large quantities of highly reactive species, such as ions, energetic electrons, exited atoms and molecules, ultraviolet photons, and metastable and active radicals. Non-thermal or cold plasmas are partially ionized gases whose electron temperatures usually exceed several tens of thousand degrees K, while the ions and neutrals have much lower temperatures. Due to the presence of reactive species at low temperature, the biological effects of non-thermal plasmas have been studied for application in the medical area with promising results. This review outlines the application of cold atmospheric pressure plasma (CAPP) in dentistry for the control of several pathogenic microorganisms, induction of anti-inflammatory, tissue repair effects and apoptosis of cancer cells, with low toxicity to healthy cells. Therefore, CAPP has potential to be applied in many areas of dentistry such as cariology, periodontology, endodontics and oral oncology.

V. Puneeth, S. Manjunatha, O. Makinde et al.

Journal of Heat Transfer • 2021

The photocatalytic nature of TiO2 finds applications in medicinal field to kill cancer cells, bacteria, and viruses under mild ultraviolet illumination and the antibacterial characteristic of Ag makes the composition Ag−TiO2 applicable for various purposes. It can also be used in other engineering appliances and industries such as humidity sensor, coolants, and in footwear industry. Hence, this study deals with the analysis of the effects of magnetic field, thermal radiation, and quartic autocatalysis of heterogeneous–homogeneous reaction in an electrically conducting Ag−TiO2−H2O hybrid nanofluid. Furthermore, the gyrotactic microorganisms are used as active mixers to prevent agglomeration and sedimentation of TiO2 that occurs due to its hydrophobic nature. The mathematical model takes the form of partial differential equations with viscosity and thermal conductivity being the functions of volume fraction. These equations are converted to ordinary differential equations by using similarity transformation and are solved by RKF-45 method with the aid of shooting method. It is observed that the increase in the size of the needle enhances the overall performance of the hybrid nanofluid. Furthermore, the temperature of the hybrid nanofluid increases with the increase in volume fraction. It is observed that the friction produced by the Lorentz force increases the temperature of the nanofluid. It is further observed that the heterogeneous reaction parameter has more significant effect on the concentration of bulk fluid than the homogeneous reaction parameter.

B. R. Sreelekshmy

Journal of Pure and Applied Microbiology • 2020

The field of MFC technology has endured immense development during the past couple of decades. During this period, electrically connected microbial communities (e communities) were studied extensively which helps the scientists in designing better versions of MFCs. Mixed bacterial culture and sometimes pure culture is widely used as an efficient exoelectrogens for the successful operation of MFCs. As the literature review, many microorganisms belong to firmicutes and actinobacteria phyla and all classes of proteobacteria, archaea are widely used in MFCs for power generation. In addition mixed bacterial culture from anaerobic sludge, industrial wastes etc are also used for enhanced power generation in MFC. In the present paper, we review the prominent exoelectrogens used in MFCs operation an innovation towards bioelectricity generation. Understanding the role and mechanism of electron transfer broaden the exploration of microbes towards waste treatment and simultaneous electricity using MFC technology in various sectors generation. Synergistic and interspecies interaction also helps a lot to improve the current generation in MFC. Recently, many researchers are tried genetic engineering of particular organism and results in enhanced production and accumulation of flavin molecules and thus improved the electricity generation compared to wild type. In the light of specific characters of microorganism, the ecological knowledge of microbial resources is essential for extending the foundation and future developments in MFC. Understanding of bioelectricity production by various exoelectrogens and its changes over time in the MFC opens up a new world to combat excess energy consumption in future.

Guofang Feng, Sanqiang Gong

Microorganisms • 0

<jats:p>Mercury (Hg) methylation in mangrove sediments can result in the accumulation of neurotoxic methylmercury (MeHg). Identification of Hg methyltransferase gene hgcA provides the means to directly characterize the microbial Hg-methylating consortia in environments. Hitherto, the microbial Hg-methylating community in mangrove sediments was scarcely investigated. An effort to assess the diversity and abundance of hgcA genes and transcripts and link them to Hg and MeHg contents was made in the mangrove intertidal sediments along the urbanized Shenzhen Bay, China. The hgcA genes and transcripts associated with Thermodesulfobacteria [mainly Geobacteraceae, Syntrophorhabdaceae, Desulfobacterales, and Desulfarculales (these four lineages were previously classified into the Deltaproteobacteria taxon)], as well as Euryarchaeota (mainly Methanomicrobia and Theionarchaea) dominated the hgcA-harboring communities, while Chloroflexota, Nitrospirota, Planctomycetota, and Lentisphaerota-like hgcA sequences accounted for a small proportion. The hgcA genes appeared in greater abundance and diversity than their transcript counterparts in each sampling site. Correlation analysis demonstrated that the MeHg content rather than Hg content significantly correlated with the structure of the existent/active hgcA-harboring community and the abundance of hgcA genes/transcripts. These findings provide better insights into the microbial Hg methylation drivers in mangrove sediments, which could be helpful for understanding the MeHg biotransformation therein.</jats:p>

Nina Rose Camillone, Mary Ann Victoria Bruns, Raúl Román et al.

• 0

<jats:title>ABSTRACT</jats:title><jats:p>Soil microorganisms carry out many processes that are fundamental to soil functions. Among the millions of microbial cells present in a gram of soil, however, less than 2% are commonly estimated to be active at any point in time. Because the respiratory response of a bulk soil to carbon substrate addition would be expected to reflect the number of active cells, we hypothesized a positive correlation between active cells and soil respiration rates during substrate-induced respiration (SIR) assays. To test this, we monitored respiration and active cell counts during 24-h incubations of agricultural soil subsamples after treating with two carbon substrates or a water-only control. We enumerated active cells with the Bioorthogonal Non-canonical Amino Acid Tagging (BONCAT) method. BONCAT provides a labeled amino acid for active cells to incorporate into newly synthesized proteins, which can then be tagged with a fluorescent dye to enable enumeration by flow cytometry. Both respiration rates and active cell counts increased over time and were positively correlated with each other after 6 h of incubation. After 24 h, increases in active cells were proportionally greater than increases in respiration. Additionally, carbon-amended soils had higher respiration rates than water-only soils with similar active cell counts, suggesting differences in carbon use efficiency. Our study documents for the first time the respiratory response from<jats:italic>in-situ</jats:italic>microbial activation induced by substrate amendment of soil within 6 h, a short enough timescale to exclude most cell replication. This study also demonstrates that the correlation between active cell numbers and respiration is substrate-dependent.</jats:p><jats:sec><jats:title>IMPORTANCE</jats:title><jats:p>While many critical ecosystem services provided by soil are known to rely on microbial activity, the soil microbial community largely remains a black box. While respiration is a common indicator of bulk soil microbial activity, this study demonstrates that the relationship between respiration and the number of active cells differs based on available carbon substrates. Advancing knowledge in this area will both enable better interpretation of biological soil tests by land managers and inform researchers modeling contributions of soil microbial respiration to global carbon dynamics.</jats:p></jats:sec>

Nolwenn Callac, Carolane Giraud, Dominique Pham et al.

Microorganisms • 0

<jats:p>During their entire lifecycle, mariculture animals are farmed in water that contains various microorganisms with which they are in close associations. Microbial exchanges between the animals and their surrounding water can occur. However, little is known about the interactions between shrimp larvae and water, and more especially, about larval bacterial selection and microbiota modulation across ontogeny. To address this gap, using HiSeq sequencing targeting the V4 region of the 16S rRNA molecule, we investigated the active prokaryotic diversity and structure of healthy Penaeus stylirostris larvae and seawater. Comparisons between different larval stages revealed evidence of stage-specific microbiotas and biomarkers, a core microbiota common to all stages, and shared taxa between successive stages, suggesting vertical transmission of bacterial taxa. Comparisons between stage-specific microbiotas and core microbiotas with water storages highlighted that many taxa associated with the larvae were originally present in the natural seawater, underlining horizontal transmission of bacteria from water to larvae. As some of these lineages became active at specific larval stages, we suggest that larvae were able to modulate their microbiota. This study provides insight into larvae-microbiota interactions at the larval stage scale.</jats:p>

Francesca Comitini, Alice Agarbati, Laura Canonico et al.

Microorganisms • 0

<jats:p>Wickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific restriction enzymes (lysine K and arginine R cut sites). The LC–MS and LC–MS/MS analysis after enzymatic digestions revealed a molecular weight of 31 kDa. Bioinformatics processing and database research of digested pure killer protein showed 99% identity with a UDP-glycosyltransferase protein. Competitive inhibition assay of killer activity by cell-wall polysaccharides suggests that branched glucans represent the first receptor site of the toxin on the envelope of the sensitive target. The WA18 partially purified crude extract (PPCE) showed high stability of antimicrobial activity at the physicochemical conditions suitable for the winemaking process. Indeed, in wine WA18 was able to counteract B. bruxellensis and control the production of ethyl phenols. In addition, the strain WA18 was compatible with Saccharomyces cerevisiae in co-culture conditions with a potential application together with commercial starter cultures. These data suggest that WA18 mycocin is a promising biocontrol agent against spoilage yeasts in winemaking, particularly during wine storage.</jats:p>

Eulalia Sans-Serramitjana, Marta Jorba, Ester Fusté et al.

Microorganisms • 0

<jats:p>Cystic fibrosis (CF) is a genetic disorder in which frequent pulmonary infections develop secondarily. One of the major pulmonary pathogens colonizing the respiratory tract of CF patients and causing chronic airway infections is Pseudomonas aeruginosa. Although tobramycin was initially effective against P. aeruginosa, tobramycin-resistant strains have emerged. Among the strategies for overcoming resistance to tobramycin and other antibiotics is encapsulation of the drugs in nanoparticles. In this study, we explored the antimicrobial activity of nanoencapsulated tobramycin, both in solid lipid nanoparticles (SLN) and in nanostructured lipid carriers (NLC), against clinical isolates of P. aeruginosa obtained from CF patients. We also investigated the efficacy of these formulations in biofilm eradication. In both experiments, the activities of SLN and NLC were compared with that of free tobramycin. The susceptibility of planktonic bacteria was determined using the broth microdilution method and by plotting bacterial growth. The minimal biofilm eradication concentration (MBEC) was determined to assess the efficacy of the different tobramycin formulations against biofilms. The activity of tobramycin-loaded SLN was less than that of either tobramycin-loaded NLC or free tobramycin. The minimum inhibitory concentration (MIC) and MBEC of nanoencapsulated tobramycin were slightly lower (1–2 logs) than the corresponding values of the free drug when determined in tobramycin-susceptible isolates. However, in tobramycin-resistant strains, the MIC and MBEC did not differ between either encapsulated form and free tobramycin. Our results demonstrate the efficacy of nanoencapsulated formulations in killing susceptible P. aeruginosa from CF and from other patients.</jats:p>

Shafeer Kalathil, Rajib Chaudhuri

Materials • 0

<jats:p>Dye wastewater severely threatens the environment due to its hazardous and toxic effects. Although many methods are available to degrade dyes, most of them are far from satisfactory. The proposed research provides a green and sustainable approach to degrade an azo dye, methyl orange, by electrically active biofilms (EABs) in the presence of solid and hollow palladium (Pd) nanoparticles. The EABs acted as the electron generator while nanoparticles functioned as the electron carrier agents to enhance degradation rate of the dye by breaking the kinetic barrier. The hollow Pd nanoparticles showed better performance than the solid Pd nanoparticles on the dye degradation, possibly due to high specific surface area and cage effect. The hollow cavities provided by the nanoparticles acted as the reaction centers for the dye degradation.</jats:p>

Ayako Arai

Microorganisms • 0

<jats:p>Chronic active Epstein–Barr virus infection (CAEBV) is a disease where Epstein–Barr virus (EBV)-infected T- or NK-cells are activated and proliferate clonally. The symptoms of this dual-faced disease include systemic inflammation and multiple organ failures caused by the invasion of infected cells: inflammation and neoplasm. At present, the only effective treatment strategy to eradicate EBV-infected cells is allogeneic stem cell transplantation. Lately, the investigation into the disease’s pathogenic mechanism and pathophysiology has been advancing. In this review, I will evaluate the new definition in the 2017 WHO classification, present the advancements in the study of CAEBV, and unfold the future direction.</jats:p>

Sami Khabthani, Jean-Marc Rolain, Vicky Merhej

Microorganisms • 0

<jats:p>Antibiotics are majorly important molecules for human health. Following the golden age of antibiotic discovery, a period of decline ensued, characterised by the rediscovery of the same molecules. At the same time, new culture techniques and high-throughput sequencing enabled the discovery of new microorganisms that represent a potential source of interesting new antimicrobial substances to explore. The aim of this review is to present recently discovered nonribosomal peptide (NRP) and polyketide (PK) molecules with antimicrobial activity against human pathogens. We highlight the different in silico/in vitro strategies and approaches that led to their discovery. As a result of technological progress and a better understanding of the NRP and PK synthesis mechanisms, these new antibiotic compounds provide an additional option in human medical treatment and a potential way out of the impasse of antibiotic resistance.</jats:p>

David Redfield

Applied Physics Letters • 1981

<jats:p>A simple technique is described for selective observation of those grain boundaries in polycrystalline Si that would be most harmful to the properties of a solar cell if a cell were to be made from that material. The technique is based on the alteration of the optic axis of liquid crystals by fringing fields at the surface of polycrystalline Si. It is found that the pattern of boundaries seen this way correlates well with the pattern of the most active boundaries as seen in a light-spot scan of a solar cell. This technique has revealed that in p-type Wacker ’’Silso’’ material, the electrical properties of grain boundaries are strongly affected by heat treatment.</jats:p>

Mandy Messal, Bernard Slippers, Sanushka Naidoo et al.

Microorganisms • 0

<jats:p>Fungi represent a common and diverse part of the microbial communities that associate with plants. They also commonly colonise various plant parts asymptomatically. The molecular mechanisms of these interactions are, however, poorly understood. In this study we use transcriptomic data from Eucalyptus grandis, to demonstrate that RNA-seq data are a neglected source of information to study fungal–host interactions, by exploring the fungal transcripts they inevitably contain. We identified fungal transcripts from E. grandis data based on their sequence dissimilarity to the E. grandis genome and predicted biological functions. Taxonomic classifications identified, amongst other fungi, many well-known pathogenic fungal taxa in the asymptomatic tissue of E. grandis. The comparison of a clone of E. grandis resistant to Chrysoporthe austroafricana with a susceptible clone revealed a significant difference in the number of fungal transcripts, while the number of fungal taxa was not substantially affected. Classifications of transcripts based on their respective biological functions showed that the fungal communities of the two E. grandis clones associate with fundamental biological processes, with some notable differences. To shield the greater host defence machinery in the resistant E. grandis clone, fungi produce more secondary metabolites, whereas the environment for fungi associated with the susceptible E. grandis clone is more conducive for building fungal cellular structures and biomass growth. Secreted proteins included carbohydrate active enzymes that potentially are involved in fungal–plant and fungal–microbe interactions. While plant transcriptome datasets cannot replace the need for designed experiments to probe plant–microbe interactions at a molecular level, they clearly hold potential to add to the understanding of the diversity of plant–microbe interactions.</jats:p>

Gaurav Agrawal, Harrison Hamblin, Annabel Clancy et al.

Microorganisms • 0

<jats:p>Crohn’s disease is increasing in incidence and prevalence in younger people and is of a particularly aggressive nature. One emerging treatment targets Mycobacterium avium paratuberculosis (MAP), an organism implicated in the causation of Crohn’s disease. This study reviewed a cohort of paediatric patients with active Crohn’s disease treated with Anti-Mycobacterial Antibiotic Therapy (AMAT). Sixteen paediatric patients, the majority of whom had failed conventional immunosuppressive therapy, were treated with AMAT. Endoscopic remission was scored using the Simple Endoscopic Score for Crohn’s Disease and clinical remission was assessed using the Weighted Paediatric Crohn’s Disease Activity Index (wPCDAI). Inflammatory blood markers were also routinely recorded. Patients were followed up clinically and endoscopically during treatment after an average of two months (range 1–6) and 17 months (range 2–49), respectively. A significant reduction in both scores assessing clinical improvement (p &lt; 0.001) and mucosal healing (p &lt; 0.0078) was observed at these timepoints; 47% of patients had achieved clinical remission and 63% endoscopic remission. Haemoglobin and serum inflammatory markers normalised for more than 50% of the cohort by six months of treatment. No adverse effects were reported throughout treatment. This is the first report of Anti-Mycobacterial Antibiotic Therapy offering a safe and efficacious therapy for paediatric patients with Crohn’s disease. Further larger randomised studies are required in order to validate these findings.</jats:p>

Nikolaos Tzortzakis

Microorganisms • 0

<jats:p>Botrytis cinerea is an unbearable postharvest threat with significant economic impacts. Necrotrophic B. cinerea can readily infect ripe fruit resulting in the rapid progression of symptoms of the disease. To unravel the mechanism by which tomato fruit opposes pathogen attack, we investigated the changes in quality-related attributes as a direct response (DR) or systemic response (SR) of infected tomatoes to the B. cinerea. Additionally, the SR of protein yield and composition were studied in fruit stored at 11 °C/90% relative humidity (RH) for one week. Fungal infection accelerated ripening with increased ethylene and respiration rates. Fruit softening, ascorbic acid and β-carotene increase were associated with DR but not with the SR of the pathogen. Pathogen infection increased lipid peroxidation, causing the production of hydrogen peroxide and oxidative stress, as fruit activated both enzymatic and non-enzymatic mechanisms to trigger stress. B. cinerea increased up to 6.6% the protein yield and downregulated at least 39 proteins. Proteins involved in fruit ripening, such as an ethylene biosynthetic enzyme, were increased in wound-inoculated fruit. Moreover, antioxidant proteins, such as ascorbate peroxidase-APX1 and superoxide dismutase-SOD, increased in infected tomatoes, as these proteins are involved in reactive oxygen species detoxification. Constitutively-expressed proteins tended to be either increased (chaperonin and malate dehydrogenase) or remained unaffected (dehydrin) by pathogen inoculation. Protein levels involved in the metabolism of carbohydrate, the pentose phosphate pathway, terpenoid and flavonoid biosynthesis were differently affected during the treatments. By enabling a better understanding of the fungal direct or systemic response on fruit quality and ripening through biochemical and proteome studies, we may improve the plant–pathogen interaction and complexity.</jats:p>

Rustamzhon Melikov, Francesco De Angelis, Rosalia Moreddu

• 0

<jats:title>Abstract</jats:title><jats:p>Microelectrode matrices have been extensively used in the past 30 years as a reliable platform to record the extracellular activity of cells traditionally regarded to as excitable, i.e. brain cells and muscle cells. Meanwhile, fundamental biology studies on cancer cells since the 1970s reveal that they exhibit altered functionalities of ion channels, membrane potentials, metabolism, and communication mechanisms when compared to their healthy counterparts. In this work, we present for the first time the presence of extracellular voltage spikes occurring at high frequencies (0.1-3.5 kHz) in breast cancer cells, resembling the ones observed in excitable cells, and the possibility to record them with 30 µm TiN microelectrode matrices. These preliminary findings may open a new path for exploration in a variety of research fields, enabling the access to bioelectrical dynamics in cancer cells and cell networks, targeting bioelectricity as a tool in anticancer drug development and cancer diagnostics, as well as provide a market expansion for companies commercializing microelectrodes and microelectrode recording systems.</jats:p>

Akikazu Sakudo, Makoto Haritani, Koichi Furusaki et al.

Microorganisms • 0

<jats:p>Xanthomonas campestris pv. campestris (Xcc) is an important seed-borne bacterial pathogen that causes black rot in brassica. Current seed disinfection methods for Xcc have disadvantages; chemical treatment has associated environmental risks, hot water immersion reduces germination, and dry heat treatment is protracted. Here, we treated Xcc-contaminated seeds with CAC-717, a recently developed disinfectant produced by applying an electric field and water flow to distilled water containing calcium hydrogen carbonate to produce mesoscopic crystals. The decimal reduction time (D-value) of Xcc suspension (8.22 log10 colony forming units (CFU)/mL) by CAC-717 treatment was 0.319 min. Treatment of Xcc-contaminated cabbage seeds at 25 °C for 30 min with CAC-717 significantly reduced bacterial cell numbers recovered from the seeds (0.36 log10 CFU/mL (SEM (standard error of the mean) = 0.23 log10 CFU/mL)) compared with distilled water treatment (3.52 log10 CFU/mL (SEM = 0.12 log10 CFU/mL)). Moreover, there was a lower incidence of black rot after treatment with CAC-717 (26.67% ± 3.33%) versus distilled water (56.67% ± 8.82%). For non-contaminated seeds, there was no significant difference in germination rate and plant stem length between distilled water and CAC-717 treatment after 5 days of cultivation. In conclusion, CAC-717 is a promising seed disinfectant without deleterious effects on germination or plant growth.</jats:p>

Tobias Grünzel, Young Joo Lee, Karsten Kuepper et al.

Beilstein Journal of Nanotechnology • 0

<jats:p>Silicon as the negative electrode material of lithium ion batteries has a very large capacity, the exploitation of which is impeded by the volume changes taking place upon electrochemical cycling. A Si electrode displaying a controlled porosity could circumvent the difficulty. In this perspective, we present a preparative method that yields ordered arrays of electrochemically competent silicon nanotubes. The method is based on the atomic layer deposition of silicon dioxide onto the pore walls of an anodic alumina template, followed by a thermal reduction with lithium vapor. This thermal reduction is quantitative, homogeneous over macroscopic samples, and it yields amorphous silicon and lithium oxide, at the exclusion of any lithium silicides. The reaction is characterized by spectroscopic ellipsometry for thin silica films, and by nuclear magnetic resonance and X-ray photoelectron spectroscopy for nanoporous samples. After removal of the lithium oxide byproduct, the silicon nanotubes can be contacted electrically. In a lithium ion electrolyte, they then display the electrochemical waves also observed for other bulk or nanostructured silicon systems. The method established here paves the way for systematic investigations of how the electrochemical properties (capacity, charge/discharge rates, cyclability) of nanoporous silicon negative lithium ion battery electrode materials depend on the geometry.</jats:p>

Falk Harnisch, Korneel Rabaey

ChemSusChem • 2012

<jats:title>Abstract</jats:title><jats:p>Microbial bioelectrochemical systems (BESs) employ whole microorganisms to catalyze electrode reactions. BESs allow electricity generation from wastewater, electricity‐driven (bio)production, biosensing, and bioremediation. Many of these processes are perceived as highly promising; however, to date the performance of particularly bioproduction processes is not yet at the level required for practical applications. Critical to enabling high catalytic activity are the electrochemically active microorganisms. Whether the biocatalyst comes as a planktonic cell, a surface monolayer of cells, or a fully developed biofilm, effective electron transfer and process performance need to be achieved. However, despite many different approaches and extensive research, many questions regarding the functioning of electroactive microorganisms remain open. This is certainly due to the complexity of bioelectrochemical processes, as they depend on microbial, electrochemical, physical‐chemical, and operational considerations. This versatility and complexity calls for a plethora of analytical tools required to study electrochemically active microorganisms, especially biofilms. Here, we present an overview of the parameters defining electroactive microbial biofilms (EABfs) and the analytical toolbox available to study them at different levels of resolution. As we will show, a broad diversity of techniques have been applied to this field; however, these have often led to conflicting information. Consequently, to alleviate this and further mature the field of BES research, a standardized framework appears essential.</jats:p>

P. NOVAK, K. MUELLER, K. S. V. SANTHANAM et al.

ChemInform • 1997

<jats:title>Abstract</jats:title><jats:p>ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.</jats:p>

Irina Chepurnaya, Evgenia Smirnova, Mikhail Karushev

Batteries • 0

<jats:p>As a cathode material for lithium-ion batteries, lithium iron phosphate (LiFePO4, LFP) successfully transitioned from laboratory bench to commercial product but was outshone by high capacity/high voltage lithium metal oxide chemistries. Recent changes in the global economy combined with advances in the battery pack design brought industry attention back to LFP. However, well-recognized intrinsic drawbacks of LiFePO4 such as relatively low specific capacity and poor electronic and ionic conductivity have not yet been fully mitigated. Integration of electrochemically active electron-conducting polymers (EAECPs) into the cathode structure to replace conventional auxiliary electrode components has been proposed as an effective strategy for further performance improvement of LFP batteries. In this review, we show how various combinations of polymer properties/functions have been utilized in composite LiFePO4 electrodes containing EAECP components. We present recent advances in the cathode design, materials, and methods and highlight the impact of synthetic strategies for the cathode preparation on its electrochemical performance in lithium-ion cells. We discuss advantages and limitations of the proposed approaches as well as challenges of their adoption by the battery manufactures. We conclude with perspectives on future development in this area.</jats:p>

Hiromasa Goto

Advanced Functional Materials • 2009

<jats:title>Abstract</jats:title><jats:p>Optically active polythiophene (PT*) is successfully prepared by electrochemical polymerization using a cholesteric liquid crystal (CLC) electrolyte solution. Polarizing optical microscopy observations of the polymer reveal a well‐resolved fingerprint texture similar to the optical texture of the CLC. Circular dichroism measurements indicate a Cotton effect. The PT* film produced by the asymmetric polymerization in CLC exhibits a variable diffraction function, electrochemically driven refractive index modulation, and electrochromism originating from the periodic dielectric structure, representing a form of structural electrochromism.</jats:p>

Dyovani Coelho, Giuliana Luiz, Sergio Machado

Journal of the Brazilian Chemical Society • 0

<jats:p>The well-known electrochemical probe Fe(CN)63-/Fe(CN)64- is widely used for estimating the electrochemically active area of electrodes modified with carbon nanotubes, conductive polymers, enzymes, etc. In this study, we used the platinum electrode, smooth or platinized with different roughness factors, to demonstrate that such a redox couple fails to respond to a surface roughness variation. We determined the roughness factors of the Pt surfaces by atomic force microscopy (AFM) images, which yielded values between 2.72 and 25.91. Almost the same values were found by using the charge of the hydrogen monolayer desorption obtained from steady-state cyclic voltammetry experiments performed in an acid medium. They were then compared with those provided by peak current in voltammetry or chronoamperometry with Fe(CN)6 3-/Fe(CN)64- which all yielded values nearly to one. Such comparison demonstrates that the electrochemical behavior of the redox probe is an outer sphere reaction with a quite small interaction with the electrode surface, thus not being suitable to be related with active areas.</jats:p>

Kiyoshi Otsuka, Ichiro Yamanaka

Chemistry Letters • 1987

<jats:title>Abstract</jats:title> <jats:p>Hydrogenation of 2-propanol into propane was caused by the hydrogen atoms electrochemically generated on Pd-black of the electrocatalytic cell Pd/H3PO4/Pd. The reaction was also caused by the hydrogen generated through spillover and reverse spillover between Pd and H3PO4. Under closed circuit conditions, the latter hydrogenation over the anode Pd was retarded because of the inhibition of the reverse spillover.</jats:p>

Zhiyan Chen, Xiangzhen Ye, Dhamodharan A et al.

• 0

<title>Abstract</title> <p>In several industries, such as food, pharmaceuticals, and environmental protection, the identification of analytes at extremely low concentrations is essential. In the food standardization field, electrochemical sensors are one of the key technologies for determining food quality and making medical diagnoses. Sensor design is dependent on electrochemically active characteristics of the selected material to alter the electrode. For rapid and accurate detection of caffeine (CAF), we technologically built an electrochemical sensor based on functionalized multi-walled carbon nanotubes (f-MWCNTs/GCE). The functionalized material was characterized by XRD, Raman, FT-IR, FE-SEM, HR-TEM, EDX and the mapping of elements. The component’s natural virtue and cooperative connection demonstrate enhanced electrocatalytic activity, as evidenced by the component’s decreased overpotential, increased electron transfer, improved sensing and selectivity, broad linear range, and low detection limit toward the selected analyte. CAF was found to have broad linear ranges of concentrations 5.3 to 166 µM, with detection limits of 0.043 µM. 9.13 µA. µm^− 1 is the designed electrode's sensitivity. High selectivity, stability, repeatability and reproducibility were also demonstrated by the electrode. Crucially, the investigation was effective in identifying and measuring the aforementioned element in authentic specimens. In addition, the sensor demonstrated efficacy in detecting CAF in drinks, yielding good recoveries ranging from 96.4–102.4%. This suggests that the sensor holds desirable potential for identifying CAF real substances.</p>

Maximilian Schalenbach

• 0

<p>The electrochemically active surface area (ECSA) of an electrode can be estimated by means of double layer capacitance (DLC) measurements using impedance spectroscopy and cyclic voltammetry. In this study, the responses of smooth and porous gold electrodes (chosen as model systems) to both methods are measured and described by physical models. I point out that diffusion limited adsorption processes significantly contribute to the measured responses and thus complicate the estimation of DLCs. Impedance is derived to be in most cases more suitable for measuring DLCs as higher frequencies are available and as contributions of serial resistances and capacitances can be separately evaluated in the frequency domain. The relaxation properties in the frequency domain are shown to display a useful tool to survey the accuracy of the DLC estimation. The DLCs of polished gold electrodes are shown to be proportional to their geometric surface area. From these measurements a specific DLC of 6±2 μF/cm² of gold in perchloric acid is determined, which agrees with the lowest reported values of strongly scattering data in the literature. A handy flow chart for experimentalists to determine electrode capacitances from impedance spectra is proposed.</p>

Shiling Zheng, Bingchen Wang, Ying Li et al.

Journal of Basic Microbiology • 2017

<jats:sec><jats:label/><jats:p>Iron (III)‐reducing bacteria (IRB) play significant roles in the degradation of naturally occurring organic matter and in the cycling of heavy metals in marine and freshwater sediments. Our previous study has demonstrated the co‐occurrence of <jats:italic>Geobacteraceae</jats:italic> and <jats:italic>Methanosarcinamazei</jats:italic> as aggregates in the iron (III)‐reducing enrichments from a coastal gold mining site on the Jiehe River. The IRB community in the enriched sediments was dominated by members of <jats:italic>Comamonadacea</jats:italic>, <jats:italic>Clostridiaceae</jats:italic>, <jats:italic>Bacillaceae</jats:italic>, <jats:italic>Bacteroidaceae</jats:italic>, and <jats:italic>Geobacteraceae</jats:italic>. Furthermore, four representative strains (JhA, JhB, JhC‐1, and JhC‐2) were isolated and found to belong to the genus of <jats:italic>Anaerosinus</jats:italic>, <jats:italic>Bacillus</jats:italic>, and <jats:italic>Clostridium</jats:italic> with 97.31–98.82% identity of 16S rRNA genes. The iron (III)‐reducing ability of all these isolates was identified. Interestingly, JhA showed electrochemical activity with chronoamperometry (CA) and cyclic voltammetry (CV), indicating its ability to oxidize ethanol, liberate, and transfer electrons, thus, expanding our knowledge of a new genus with electrochemical activity. The results revealed the cultivability and electrochemical activity of IRB in coastal riverine sediment and indicated that JhA was an unknown extracellular electron producer with the ability to reduce iron (III). This study expands our knowledge of the electrochemical characterization of the genus <jats:italic>Anaerosinus</jats:italic>. It is reasonable to expect that these isolates have potential applications in heavy metal bioremediation operations in natural environments.</jats:p></jats:sec>

A. C. Marques, L. Santos, M. N. Costa et al.

Scientific Reports • 0

<jats:title>Abstract</jats:title><jats:p>Electrochemically active bacteria (EAB) have the capability to transfer electrons to cell exterior, a feature that is currently explored for important applications in bioremediation and biotechnology fields. However, the number of isolated and characterized EAB species is still very limited regarding their abundance in nature. Colorimetric detection has emerged recently as an attractive mean for fast identification and characterization of analytes based on the use of electrochromic materials. In this work, WO<jats:sub>3</jats:sub> nanoparticles were synthesized by microwave assisted hydrothermal synthesis and used to impregnate non-treated regular office paper substrates. This allowed the production of a paper-based colorimetric sensor able to detect EAB in a simple, rapid, reliable, inexpensive and eco-friendly method. The developed platform was then tested with <jats:italic>Geobacter sulfurreducens</jats:italic>, as a proof of concept. <jats:italic>G. sulfurreducens</jats:italic> cells were detected at latent phase with an RGB ratio of 1.10 ± 0.04 and a response time of two hours.</jats:p>

Daichi Yoshizu, Soranosuke Shimizu, Miyu Tsuchiya et al.

Microorganisms • 0

<jats:p>Studies have used anaerobic-digester sludge and/or effluent as inocula for bioelectrochemical systems (BESs), such as microbial fuel cells (MFCs), for power generation, while limited studies have isolated and characterized electrochemically active bacteria (EAB) that inhabit anaerobic digesters. In the present work, single-chamber MFCs were operated using the anaerobic-digester effluent as the sole source of organics and microbes, and attempts were made to isolate EAB from anode biofilms in MFCs by repeated anaerobic cultivations on agar plates. Red colonies were selected from those grown on the agar plates, resulting in the isolation of three phylogenetically diverse strains affiliated with the phyla Bacillota, Campylobacterota and Deferribacterota. All these strains are capable of current generation in pure-culture BESs, while they exhibit different electrochemical properties as assessed by cyclic voltammetry. The analyses of their cell-free extracts show that cytochromes are abundantly present in their cells, suggesting their involvement in current generation. The results suggest that anaerobic digesters harbor diverse EAB, and it would be of interest to examine their ecological niches in anaerobic digestion.</jats:p>

Justin Biffinger, Meghann Ribbens, Bradley Ringeisen et al.

Biotechnology and Bioengineering • 2009

<jats:title>Abstract</jats:title><jats:p>Metal reduction assays are traditionally used to select and characterize electrochemically active bacteria (EAB) for use in microbial fuel cells (MFCs). However, correlating the ability of a microbe to generate current from an MFC to the reduction of metal oxides has not been definitively established in the literature. As these metal reduction assays may not be generally reliable, here we describe a four‐ to nine‐well prototype high throughput voltage‐based screening assay (VBSA) designed using MFC engineering principles and a universal cathode. Bacterial growth curves for <jats:italic>Shewanella oneidensis</jats:italic> strains DSP10 and MR‐1 were generated directly from changes in open circuit voltage and current with five percent deviation calculated between each well. These growth curves exhibited a strong correlation with literature doubling times for <jats:italic>Shewanella</jats:italic> indicating that the VBSA can be used to monitor distinct fundamental properties of EAB life cycles. In addition, eight different organic electron donors (acetate, lactate, citrate, fructose, glucose, sucrose, soluble starch, and agar) were tested with <jats:italic>S. oneidensis</jats:italic> MR‐1 in anode chambers exposed to air. Under oxygen exposure, we found that current was generated in direct response to additions of acetate, lactate, and glucose. Biotechnol. Bioeng. 2009;102: 436–444. © 2008 Wiley Periodicals, Inc.</jats:p>

Atsumi Hirose, Takuya Kasai, Motohide Aoki et al.

Nature Communications • 0

<jats:title>Abstract</jats:title><jats:p>Electrochemically active bacteria (EAB) receive considerable attention for their utility in bioelectrochemical processes. Although electrode potentials are known to affect the metabolic activity of EAB, it is unclear whether EAB are able to sense and respond to electrode potentials. Here, we show that, in the presence of a high-potential electrode, a model EAB <jats:italic>Shewanella oneidensis</jats:italic> MR-1 can utilize NADH-dependent catabolic pathways and a background formate-dependent pathway to achieve high growth yield. We also show that an Arc regulatory system is involved in sensing electrode potentials and regulating the expression of catabolic genes, including those for NADH dehydrogenase. We suggest that these findings may facilitate the use of EAB in biotechnological processes and offer the molecular bases for their ecological strategies in natural habitats.</jats:p>

Yana Mersinkova, Hyusein Yemendzhiev

Journal of Advances in Biology &amp; Biotechnology • 0

<jats:p>Aims: This study aims to define criteria for the main physical and chemical characteristics of the environmental niches populated with electrochemically active microorganisms, capable to perform anaerobic respiration and potentially used in Bio-electrochemical systems such as Microbial Fuel Cells.  &#x0D; Study Design: In this study, specific parameters of the environment in water bodies (such as lakes, streams etc.) and their bottom layers are analyzed. The main parameters of interest include the concentration of dissolved oxygen in the water column, the organic matter content in the sediments and the presence of alternative electron acceptors (such as iron and manganese ions) to support anaerobic respiration. Sediment microorganisms are characterized for their electrochemical and biodegradation activity.&#x0D; Place and Duration of Study: The tested sediment and water samples were collected from "Poda" Protected Site located on the outfall of Lake “Uzungeren”, south of City of Burgas, Bulgaria.&#x0D; Methodology: The samples were analyzed employing TGA, ICP and microbiological methods focusing on chemical, physical and biological conditions available for anaerobic respiration in this ecological niche.&#x0D; Results: The results show very low concentrations of dissolved oxygen (from 1.4 to 2.2 mg/dm3 in the various locations). The conductivity and the pH values ​​measured were relatively high and the mean values obtained are 5230 μS/cm and 8.2 respectively. The sediment samples demonstrated very high organic matter content (22.5% of the dry mass) and relatively high levels of iron and manganese.&#x0D; Microbial fuel cell powered by mixed bacterial culture isolated from the tested sediment samples demonstrated stable performance reaching power density of 3.5 W/m2 and the COD removal rate of 42 mgO2/dm3 per day.&#x0D; Conclusion: The result confirms the initial hypothesis that electrochemically active microorganisms are available in environments with high concentration of organic matter, iron and manganese in combination with low availability of dissolved oxygen. Mixed culture of anaerobic bacteria isolated from the tested sediment sample was successfully implemented to power Microbial Fuel Cell.</jats:p>

Qi Deng, Xiaoyi Huangyang, Xin Zhang et al.

Advanced Energy Materials • 2022

The low electrocatalytic activity of pristine graphite felt (GF) electrodes toward V(II)/V(III) and V(IV)/V(V) redox couples is a major concern in vanadium redox flow batteries (VRFBs). For overcoming this challenge, herein a novel composite electrode is proposed comprising of two components: multidimensional frame carbon (MFC) derived from edge‐rich carbon and GF that serves as the frame for the in situ growth of MFC. The high electrocatalytic activity, rapid charge migration, and reduced local current emanating from the 0D, 2D, and 3D coexistent structures of the MFC material, respectively, enhance the performance of the GF. Consequently, the battery assembled using the MFC GF electrode achieves a maximum current density of 500 mA cm−2, along with high stability and preeminent energy efficiency at a current density of 200 mA cm−2 for over 400 cycles. For the first time via density functional theory analysis on VRFBs, this study reveals that the edge‐rich carbon atoms possess higher electrocatalytic activity in both positive and negative electrolytes than the plane carbon atoms and heteroatoms. Therefore, this study is of immense significance in guiding and promoting the application of edge‐rich carbon in the battery‐based energy storage industry.

Yanping Wang, Xusen Cheng, Ke Liu et al.

ACS Applied Materials &amp; Interfaces • 2022

Microbial fuel cells (MFCs) are promising ecofriendly techniques for harvesting bioenergy from organic and inorganic matter. Currently, it is challenging to design MFC anodes with favorable microorganism attachment and fast extracellular electron transfer (EET) rate for high MFC performance. Here we prepared N-doped carbon nanotubes (NCNTs) on carbon felt (CF) and used it as a support for growing hierarchical Co8FeS8-FeCo2O4/NCNTs core-shell nanostructures (FeCo/NCNTs@CF). We observed improved wettability, specific areal capacitance, and diffusion coefficient, as well as small charge transfer resistance compared with bare CF. MFCs equipped with FeCo/NCNTs@CF displayed a power density of 3.04 W/m2 and COD removal amount of 221.0 mg/L/d, about 47.6 and 290.1% improvements compared with that of CF. Biofilm morphology and 16s rRNA gene sequence analysis proved that our anode facilitated the enrichment growth of exoelectrogens. Flavin secretion was also promoted on our hierarchical elelctrode, effectively driving the EET process. This work disclosed that hierarchical nanomaterials modified electrode with tailored physicochemical properties is a promising platform to simultaneously enhance exoelectrogen attachment and EET efficiency for MFCs.

Tonni Agustiono. Kurniawan, M. Othman, Xue Liang et al.

Sustainability • 2022

Currently, access to electricity in the cities of the Global South is so limited that electrification remains low in rural areas. Unless properly tackled, one-third of the world’s cities will suffer from energy scarcity. The emergence of microbial fuel cell (MFC) technology accelerates the deployment of decentralized and sustainable energy solutions that can address the looming energy shortage. This review consolidates scattered knowledge into one article about the performance of MFC in optimizing electricity generation from phosphorus (P)-laden wastewater, while removing the target nutrient from wastewater simultaneously. It is obvious from a literature survey of 108 published articles (1999–2022) that the applications of MFC for building a self-powered municipal water treatment system represents an important breakthrough, as this enables water treatment operators to generate electricity without affecting the atmospheric balance of CO2. Using a pyrite-based wetland MFC, about 91% of P was removed after operating 180 days, while generating power output of 48 A/m2. Unlike other techniques, MFCs utilize bacteria that act as micro-reactors and allow substrates to be oxidized completely. The Earth’s tiniest inhabitants can efficiently transform the chemical energy of organic matter in unused wastewater either into hydrogen gas or electricity. This facilitates wastewater treatment plants powering themselves in daily operation or selling electricity on the market. This MFC technology radically changes how to treat wastewater universally. By exploring this direction along the water–energy–food nexus, MFC technology could transform wastewater treatment plants into a key sustainability tool in the energy sector. This suggests that MFCs provide a practical solution that addresses the need of global society for clean water and electricity simultaneously.

Lei Xu, Guoquan Zhang, Guang'en Yuan et al.

RSC Advances • 2015

In this study, an aerobic membrane bioreactor (MBR) equipped with anthraquinone–disulphonate/polypyrrole (AQDS/PPY) composite modified polyester (PT) flat membrane serving as the cathode of a dual-chamber microbial fuel cell (MFC) was developed for wastewater treatment, energy recovery and membrane fouling mitigation. Various physicochemical characteristic parameters were investigated to determine the surface properties of the AQDS/PPY/PT membrane. During most of the operation period, the chemical oxygen demand and NH4+–N removal efficiencies of this novel MFC–MBR coupled system averaged 92.5% and 70.6%, respectively. Over the hydraulic retention time of 11.58 h and the external resistance of 1000 Ω, a maximum power density of 0.35 W m−3 and a current density of 2.62 A m−3 were obtained, meanwhile, the membrane fouling mitigation achieved the best status the H2O2 concentration in membrane effluent also reached the highest value of 2.1 mg L−1. The effective membrane fouling mitigation was attributed mainly to the continuous self-generated bio-electricity of MFC, which not only accelerates the back-diffusion of negative charged foulants away from the membrane surface through the electrostatic repulsion, but also realizes membrane chemical cleaning through the in situ electrogenerated H2O2 and even ˙OH radicals on the membrane surface and/or inside the membrane pore from the self-sustainable heterogeneous electro-Fenton process. Though the electricity recovery of the MFC–MBR coupled system was much lower than other high-output MFC systems, this study provided a new insight into the membrane anti-fouling mechanism and will arouse extensive interests to explore more high-efficiency catalytic membrane materials to maximize power output and minimize membrane fouling.

Yihua Li, Jiaqi Sun, Lifen Liu et al.

Environmental Science: Nano • 2017

In this study, a photocatalytic composite membrane (PCM) coated with CoFe2O4(–rGO) and polyvinylidene fluoride (PVDF) on a carbon fiber cloth was firstly prepared by inclusion of nanoparticles in a PVDF casting solution. The PCM with CoFe2O4(–rGO) functioned as the cathode membrane in a photocatalysis-assisted MFC-MBR system. Comparison tests with four types of MFe2O4 photo-catalysts (M = Ni, Fe, Co, Zn) in PCM indicated that CoFe2O4 had the highest oxygen reduction reaction (ORR) activity. Upon compositing with reduced graphene oxide (rGO), the CoFe2O4–rGO greatly improved the catalytic activity. Photocatalysis in the cathode greatly promoted both power generation and contaminant removal. The maximum power density of 942 mW m−3 (versus anode volume) was achieved using this PCM with CoFe2O4–rGO, under visible-light irradiation, and the removal of tetracycline hydrochloride antibiotics in a photocatalysis-assisted MFC-MBR system was higher than that without irradiation. By efficiently decomposing recalcitrant substances, the photocatalysis-assisted MFC-MBR system exhibits better and broader application potential in wastewater treatment than a conventional MFC-MBR system. The beneficial effects of nanoparticles on flux and conductivity in the PVDF casting solution were also evaluated.

Shaojun Zhang, W. Tong, Mingyu Wang

Ferroelectrics • 2021

Abstract Improving the power output and other power generation performance is the technical bottleneck restricting the industrial application of microbial fuel cell (MFC). Modification of the anode using nanomaterials can significantly increase the power output of MFC. The negatively charged characteristics of Rhodopseudomonas palustris was utilized to propose electroplating of graphene on the surface of biochar, and preparation of polyaniline (PANI) modified biochar electrode by in situ polymerization. Thus, a graphene oxide/polyaniline modified biochar (GO/PANI@Biochar) anode was prepared. Thus, compared the effects of GO/PANI@Biochar, biochar, traditional carbon cloth (CC), and graphite felt (GF) anodes on the power generation performance of MFC. The results showed that the contact angle θ of the new anode was as low as 0°. The biocompatibility is good, and a large number of electricity-producing microorganisms adhere to the surface of the anode material. The maximum power density of GO/PANI@Biochar anode MFC reached to 2025 mW/m2, which was 72.12% higher than that of unmodified biochar, and it was 3.5, 4.39 times that of traditional GF and CC. The maximum output voltage was 6.12% higher than before modification, 15.56% and 23.8% higher than traditional GF and CC anodes. GO/PANI@Biochar anode utilized the advantages of GO conductivity and biochar high biocompatibility effectively. The synergism of them can significantly improve the current and power density of MFC.

Liping Fan, Junyi Shi, Yaobin Xi

Membranes • 0

<jats:p>Low power production and unstable power supply are important bottlenecks restricting the application of microbial fuel cells (MFCs). It is necessary to explore effective methods to improve MFC performance. By using molasses wastewater as fuel, carbon felt as an electrode, and the mixture of K3[Fe(CN)6] and NaCl as a catholyte, an MFC experimental system was set up to study the performance of MFCs with three different proton exchange membranes. A Nafion membrane was used as the basic material, and polyvinylidene fluoride (PVDF) and acetone-modified PVDF were used to modify it, respectively. The experimental results show that a PVDF-modified membrane can improve the water absorption effectively and, thus, make the MFC have greater power generation and better wastewater treatment effect. The acetone-modified PVDF can further improve the stability of output power of the MFC. When the acetone-modified PVDF was used to modify the Nafion membrane, the steady output voltage of the MFC was above 0.21 V, and the Chemical Oxygen Demand (COD) removal rate for molasses wastewater was about 66.7%, which were 96.3% and 75.1% higher than that of the MFC with the ordinary Nafion membrane. Membrane modification with acetone-modified PVDF can not only increase the output voltage of the MFC but also improve the stability of its output electrical energy.</jats:p>