Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
K Di Gleria, C.M Halliwell, C Jacob et al.
FEBS Letters · 1997
A cysteine residue was introduced close to the active site of β‐lactamase I by site‐directed mutagenesis to replace tyrosine‐105 and was subsequently modified with an electroactive SH‐specific reagent, N ‐(2‐ferrocene‐ethyl)maleimide. The resulting modified enzyme became electroactive, showing good quasi‐reversible electrochemistry which was characteristic of the attached ferrocene moiety while retaining its specific enzymatic activity. In the presence of a suicide substrate, 6β‐iodopenicillanic acid, the redox potential shifted +20 mV suggesting that the label was sensitive to changes in the active site of the enzyme.
Brenda Guadalupe Molina García
· 2020
Development of polymeric biomaterials with tailored properties is essential for expanding biotechnologies and, therefore, proposing novel solutions for diagnostic and treatments in modern medicine. In order to contribute with such expansion, this research suggests different strategies to modify intrinsically conducting polymers (ICPs) and overcome their few limitations. Three main engineering approaches were used to combine ICPs advantages with others from conventional insulating polymers and biopolymers, optimizing their performance as electrochemical biomaterials on tissues engineering, biomimetic platforms, actuators and specially on the biosensing field. The first strategy evaluated in this Thesis was designed to take advantage of the “grafting-through”technique and prepare graft copolymers with ICPs backbones. The incorporation of well-known biocompatible polymers like polyethylene glycol (PEG) and polycaprolactone (PCL) into ICP backbones, increased the cell viability in presence of the synthetized copolymers. Such modifications and the ICPs electroactivity allowed to estimate the copolymers performance as electrochemical sensors of biomolecules. The second approach was planned to prepare free-standing, flexible and electroactive films for the electrochemical detection of bacterial infections. The excellent mechanical properties of isotactic polypropylene (i-PP) plastic, combined with an ICP like poly (3,4-ethylendioxythiophene) (PEDOT), enabled the obtained a novel composite with good dimensional stability to be applied as electrochemical platform for bacterial detection. This composite was able to perceive extracellular nicotinamide adenine dinucleotide (NADH), generated from the respiration reactions of bacteria, and distinguishing prokaryotic microbes from eukaryotic cells. In addition, with a small adjustment, the generated films exhibited qualities as electroactive bioplatforms for tissue engineering. Finally, the third strategy fashioned an electroactive multi-functional nanomembrane for applications of flexible biomedical implants. A layer-by-layer assembly (LbL) was used to integrate the PEDOT electroactivity to the poly(lactic acid) (PLA) biopolymer. The self-supported nanomembrane of 5 layers, showed benefits as biomimetic platforms for selective ion and ATP transport, as well as actuator/artificial muscles. Overall, the characterization studies of the electroactive and biocompatible composites presented in this Thesis, offer a comprehensive view on how modifications in ICPs optimize its abilities as biomaterials and open a wide range of possible applications in biomedicine. El desarrollo de biomateriales poliméricos con propiedades específicas, es esencial para la expansión biotecnológica y, por lo tanto, para el diseño de soluciones novedosas en el diagnóstico y tratamientos de enfermedades en la medicina moderna. Con el objetivo de contribuir con dicha expansión, esta investigación propone diferentes estrategias de modificación en polímeros conductores intrínsecos (ICPs por sus siglas en ingles), y superar con ello sus pocas limitaciones. Tres principales enfoques de ingeniería fueron utilizados para combinar las ventajas de ICPs con las de otros polímeros convencionales y biopolímeros, optimizando su rendimiento como biomateriales electroquímicos en ingeniería de tejidos, plataformas biomiméticas, actuadores y, especialmente, en el campo de la biodetección. La primera estrategia evaluada en esta Tesis, fue diseñada para aprovechar la técnica de injerto y preparar copolímeros con una cadena principal de ICP. Empleando esta técnica, la incorporación de polímeros biocompatibles, como el polietilenglicol (PEG) y la policaprolactona (PCL), en la cadena principal de un ICP, aumentó la viabilidad celular en presencia de los copolímeros formados. Dichas modificaciones y la electroactividad de los ICPs, permitieron estimar el rendimiento de los copolímeros como sensores electroquímicos de biomoléculas. El segundo enfoque fue planeado para preparar películas auto soportables, flexibles y electroactivas, que permitieran la detección electroquímica de infecciones bacterianas. Las excelentes propiedades mecánicas del polipropileno isotáctico (i-PP) en combinación con un ICP, como el poli (3,4-etilendioxitiofeno) (PEDOT), permitieron obtener un nuevo compuesto electroquímico capaz de percibir el dinucleótido adenina de nicotianamina (NADH por su siglas en ingles), generado extracelularmente durante las reacciones respiratorias de las bacterias, y distinguir los microbios procariotas de las células eucariotas. Además, con un pequeño ajuste, las películas generadas exhibieron cualidades como bioplataformas electroactivas para la ingeniería de tejidos. Finalmente, con la tercera estrategia se diseñó una nanomembrana electroactiva multifuncional, para aplicaciones de implantes biomédicos flexibles. Un ensamble de capa por capa, fue utilizado para integrar la electroactividad del PEDOT con el biopolímero ácido poli láctico (PLA por sus siglas en ingles). La nanomembrana auto soportable de 5 capas, mostró beneficios como plataforma biomimética para el transporte selectivo de iones y adenosín trifosfato; o como músculos artificiales o actuadores. En general, los estudios de caracterización de los compuestos electroactivos y biocompatibles presentados en esta Tesis, ofrecen una visión integral de cómo las modificaciones en los ICPs optimizan sus capacidades como biomateriales, y abren una amplia gama de posibles aplicaciones en biomedicina.
Sandra Mendoza, Eduardo Castaño, Yunny Meas et al.
Electroanalysis · 2004
Abstract In this work, we present a method to analyze the voltammetric response of reversible redox systems involving molecules that, bearing m non‐interactive electroactive sites, can undergo fast complexation equilibria with host molecules present at concentrations of the same order of magnitude as those of the electroactive guest. The approach focuses on systems for which the relative values of the binding constants for the oxidized and reduced forms of the guest result in the displacement of the voltammetric response of the electroactive molecule as the concentration of the host is increased in the electrolytic solution. This behavior is commonly known as “one wave shift behavior”. Based on a series of assumptions, the method allows calculation of all the thermodynamic parameters that describe the electrochemical and complexation equilibria of a given host‐guest system. The main strength of the suggested method, however, relies on the fact that it only requires cyclic voltammetry data and that it can be used for systems in which large concentrations of the host can not be employed either due to important changes of the ionic strength or to solubility problems. Although the accuracy of the obtained information is limited by the quality of the data provided by the technique, and by the assumptions employed, it certainly represents an excellent starting point for subsequent refinement either using digital simulations or an independent experimental technique.
Napat Charoonrak
· 2013
Electroactive shape memory composites are smart materials that change their shapes and recover their initial shapes in the presence of an applied electric field. In this work, the focus is on fabricating an electroactive shape memory composite consisting of iron (Ill) chloride doped poly(p-phenylene)(PPP)/crosslinked poly(ε-caprolactone) (cPCL) using benzoyl peroxide (BPO) as a crosslinking agent. In addition, thermal property, electrical conductivity, and electromechanical properties of the composite as a function of crosslinking ratio. doping level, and concentration of embedded PPP are investigated. The electromechanical properties show that 3%wt BPO cPCL gives the highest storage modulus response and electrical sensitivity. However, the electrical sensitivity decreases dramatically at 0.01%v/v of embedded PPP because of the increasing of initial storage modulus. Then start to increase with increasing the concentration of PPP which can be attributed to the increases of dipole moment induction in the presence of an external electrical stimulation.
Tenille Herd
Queensland University of Technology · 2024
Organic redox flow batteries are a type of energy storage technology that uses organic molecules in a pumped organic solvent system to operate. The use of organic materials reduces our reliance on metals and disturbing the environment. Additionally, this technology could aid the widespread adoption of renewable energy technologies as part of an approach to address the climate change crisis through the use of cheap feedstock. In this work, a number of studies were conducted to assess organic compounds for their suitability for use as catholyte material within an organic redox flow battery.
Guiqin Yang, Luchao Han, Junlin Wen et al.
International Journal of Systematic and Evolutionary Microbiology · 2013
A Gram-negative, straight to slightly curved rod-shaped bacterium, motile with peritrichous flagella, designated SgZ-6 T , was isolated from an electroactive biofilm and was characterized by means of a polyphasic approach. Growth occurred with 0–5.0 % (w/v) NaCl (optimum 1 %), at pH 6.0–10.0 (optimum pH 7.0) and at 10–42 °C (optimum 30 °C) in trypticase soya broth. Phylogenetic analyses based on the 16S rRNA and gyrB genes identified the isolate as a member of a novel species of the genus Pseudomonas . Strain SgZ-6 T exhibited the highest 16S rRNA gene sequence similarity to ‘ Pseudomonas linyingensis ’ CGMCC 1.10701 (97.5 %), followed by Pseudomonas sagittaria JCM 18195 T (97.4 %), P. oleovorans subsp. lubricantis DSM 21016 T (96.6 %), P. tuomuerensis JCM 14085 T (96.5 %) and P. alcaliphila JCM 10630 T (96.4 %). Strain SgZ-6 T showed the highest gyrB gene sequence similarity of 93.7 % to ‘ P. linyingensis ’ CGMCC 1.10701 among all type strains of genus Pseudomonas . DNA–DNA pairing studies showed that strain SgZ-6 T displayed 47.1 and 40.3 % relatedness to ‘ P. linyingensis ’ CGMCC 1.10701 and P. sagittaria JCM 18195 T , respectively. The major isoprenoid quinone was ubiquinone 9 (Q-9). The whole-cell fatty acids consisted mainly of summed feature 3 (C 16 : 1 ω6 c and/or C 16 : 1 ω7 c ), C 16 : 0 and summed feature 8 (C 18 : 1 ω6 c and/or C 18 : 1 ω7 c ). The DNA G+C content of the genomic DNA was 68.1 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain SgZ-6 T is proposed to represent a novel species of the genus Pseudomonas , for which the name Pseudomonas guangdongensis sp. nov. is proposed. The type strain is SgZ-6 T ( = CCTCC AB 2012022 T = KACC 16606 T ). An emended description of the genus Pseudomonas is also proposed.
Yue Dong, Peifang Wang, Yixuan Zhang
IOP Conference Series: Earth and Environmental Science · 2020
Abstract Microbial electrochemical systems (MESs) are a promising clean energy source to directly convert waste chemicals in domestic wastewater to available electric power with synchronous pollutant removal. The physiological and biochemical behaviors of electroactive microorganisms (EAMs) is the key factor of the MESs. Dibutyl phthalate (DBP), as the emerging pollutant, widely exists in municipal wastewater which has strong ecological toxicity. So, utilization of MESs in the engineering practice of wastewater treatment must consider the impact of DBP on the physiological and biochemical behaviors of electroactive biofilm. The output voltage and power density of the MES decreased significantly with the increase of DBP in the synthetic wastewater. In addition, the EAMs resisted the stimulation of DBP by secreting more extracellular polymer substances (EPS) by microscopic observation. The composition and structure of the EPS also changed, mainly reflected in the increase of β-polysaccharide content and the expansion of its coverage area.
John Fuerst
Microorganisms · 2014
The MDPI journal Microorganisms is still very young, having been launched in 2013, but the concept of the microorganism has been in use for at least a century as a unifying principle for the discipline of microbiology, which was cemented firmly by the intellectual work of Roger Stanier and colleagues in their Microbial World and other general microbiology textbooks and related articles from the 1950s to the 1970s [1,2]. Merging the idea of the microscopic and the very small with the older idea of an organism as a living entity or cell, the concept of a microorganism enabled a real appreciation of the microbial world as one that is amenable to study using similar tools and approaches even though representing distinctly different types of reproductive units and cell organizations. In the late 20th century following the work of Carl Woese and other molecular evolutionists, biologists came to appreciate the commonality among all organisms, all being comprised of cells that bear a remarkable similarity to one another and that share a common evolutionary ancestry, and consequently with major features of a largely shared genetic code and molecular biology. In this sense microbiology and biology as a whole became unified as they never had been before.[...]
John Fuerst
Microorganisms · 2013
It is my great pleasure to welcome you to Microorganisms, a new open access journal, which is dedicated to microorganisms in all their forms and via any approach to their study. [...]
Yi Guo, Yen Wei
· 2007
Novel electroactive nanostructured polymers and organic-inorganic hybrid materials have been successfully developed for electrochemical, sensory, and tissue engineering applications. For this new class of materials, electroactivity was introduced into silica matrix through the incorporation of a silsesquioxane precursor, N,N'-bis(4'-(3- triethoxysilylpropyl-ureido)phenyl)-1,4-quinonenediimine (TSUPQD). As a derivative of emeraldine form of aniline trimer, TSUPQD was synthesized from the reaction between one equivalent of aniline trimer and two equivalents of triethoxysilylpropyl isocyanate (TESPIC) and characterized by spectroscopic methods, such as FTIR, UV-Vis, MS, NMR, and XRD. The electrochemical behavior of TSUPQD was studied by cyclic voltammetry showing two distinct oxidative states in a reversible cyclic voltammogram after doping with a protonic acid. The intrinsic electroactivity of TSUPQD is similar to polyaniline was maintained. With the presence of two triethoxylsilane groups on each TSUPQD molecule, related mesoporous electroactive hybrid materials were prepared through surfactant templated sol-gel process. The resultant hexagonally patterned porous structures were studied by BET and TEM. The materials have large surface areas and pore volumes with pore diameters ranging from 2.1 to 2.8 nm. Porous structures give rise to improved electroactivity compared to their nonporous counterparts. Multicolor silica nanospheres were prepared by coating TSUPQD onto silica surface via intermolecular condensation reaction. By varying the particle size, surface area, and organic dopant, the nanospheres exhibit multiple colors. Furthermore, luminescent nanospheres were prepared when fluorescent organic acid was employed as dopant. These nanospheres demonstrated the promising potential as sensory materials for hydrazine detection. Electroactive self-assembled monolayers were evenly attached on glass substrates, followed by covalent bonding of an adhesive oligopeptide, i.e., cyclic RGD, on the aromatic amine terminals. The biocompatibility evaluation on resultant structures from PC12 neuronal cell cultures demonstrated that this bio-derivatized substrate well supported the cell adhesion and proliferation. It is more significant that this electroactive surface stimulated spontaneous neuritogenesis of PC12 cells. Electrospun PANI-contained gelatin fibers were also investigated as conductive scaffold for tissue engineering purposes. SEM analysis of the blend fibers containing less than 3 wt% PANI revealed uniform fibers with no evidence for phase segregation. DSC studies confirmed this result. To test the utilization of PANI-gelatin blends as a fibrous matrix for supporting cell growth, H9c2 rat cardiac myoblast cell cultures were evaluated in terms of cell proliferation and morphology.
Paul J. Weimer
Microorganisms · 2022
As major structural components of plant cell walls, cellulose and hemicellulose are degraded and fermented by anaerobic microbes in the rumen to produce volatile fatty acids, the main nutrient source for the host. Cellulose degradation is carried out primarily by specialist bacteria, with additional contributions from protists and fungi, via a variety of mechanisms. Hemicelluloses are hydrolyzed by cellulolytic bacteria and by generalist, non-cellulolytic microbes, largely via extracellular enzymes. Cellulose hydrolysis follows first-order kinetics and its rate is limited by available substrate surface area. Nevertheless, its rate is at least an order of magnitude more rapid than in anaerobic digesters, due to near-obligatory adherence of microbial cells to the cellulose surface, and a lack of downstream inhibitory effects; in the host animal, fiber degradation rate is also enhanced by the unique process of rumination. Cellulolytic and hemicellulolytic microbes exhibit intense competition and amensalism, but they also display mutualistic interactions with microbes at other trophic levels. Collectively, the fiber-degrading community of the rumen displays functional redundancy, partial niche overlap, and convergence of catabolic pathways that all contribute to stability of the ruminal fermentation. The superior hydrolytic and fermentative capabilities of ruminal fiber degraders make them promising candidates for several fermentation technologies.
Patcharee Intanoo
· 2010
Elastomers that can respond to external stimuli, such as temperature and electric field, are known as dielectric elastomers, consisting of either a polar molecule or an unsaturated structure on the side chain with induced dipole moments. In our work, we prepared the electroactive polymers from blends of dielectric elastomers and a conductive polymer. For the dielectric elastomers, ethylene propylene diene elastomer (EPDM NORDEL IP 5565) was used as the matrix phase. The conductive polymers, permethylpolyazine (PAZ), were synthesized and doped with iodine at various doping levels for improving the electrical conductivity. The blends were prepared by the mechanical blending of highly doped PAZ particles with EPDM at various particle concentrations from 5 vol% to 20 vol%. The chemical structures of undoped and doped PAZ were characterized by FT-IR. The electromechanical properties were studied under an oscillatory shear mode in the frequency range 0.1-100 rad/s with electric field strength varying from 0 to 1 kV/mm at 27℃. The effects of particle concentration on storage modulus response, G', storage modulus sensitivity, G'/G'0, and electrical conductivity, σ, and dielectric constant, ɛ' at 27℃ and 100 rad/s were also studied. G' and G'/G'0 increase with increasing electric field strength, and particle concentration. The electrical conductivity and dielectric constant increase with particle concentration.
Julio Villena, Haruki Kitazawa
Microorganisms · 2017
In recent decades; scientists have provided encouraging evidence that probiotic microorganisms are valuable in the prevention and treatment of a variety of diseases.[...]
Shan Cheng, Yen Wei
· 2002
Novel nanostructured porous sol-gel materials, nanocomposites, electroactive and bioapplicable materials have been successfully developed for a wide range of perceivable applications. Several versatile nonsurfactant templated sol-gel pathways have been developed to prepare nanostructured porous materials and composites with different morphologies (e.g., monoliths, nanospheres, nanoparticles, and thin films), structures, compositions and properties. The synthetic conditions were systematically studied and optimized. The template effects on pore structure as well as synthetic process, especially template removal steps, have been investigated. The composition and pore structures were thoroughly studied with various spectroscopic and microscopic methods such as IR, TGA, SEM, TEM, BET and XRD. The obtained mesoporous materials usually exhibit high surface area, large pore volume and narrowly distributed pore diameter. The porosity can be fine tuned simply by adjusting the template concentration. The convenient synthesis as well as the distinctive structure and physical-chemical properties render these sol-gel materials great suitability for a wide range of potential applications, such as chemical and biological sensors, catalysts, drug delivery and functional coatings. Biocompatible and electroactive nanocomposites have been prepared through a biological agent (i.e., collagen) templated chemical polymerization of aniline monomers. The resultant polyaniline-collagen complexes exhibit well controlled doping-dedoping electroactivity and much enhanced solubility. Demonstrated with cell growth studies, the polyaniline-collagen complexes show improved biocompatibility in comparison to polyaniline. The new materials can be used to fabricate scaffolds, with which the effect of electrical stimuli on cell growth and differentiation can be evaluated with the hope of ultimately using electrical signal to stimulate controllable cell and tissue regeneration. Aniline derivative substituted quinoline ligand compounds and their complexes have been prepared and investigated as potential electroluminescent materials.
Zheng-Kai An, Young-Chae Song, Keug-Tae Kim et al.
Fermentation · 2023
Direct interspecies electron transfer (DIET) between electroactive microorganisms (EAMs) offers significant potential to enhance methane production, necessitating research for its practical implementation. This study investigated enhanced methane production through DIET in an anaerobic digester bio-augmented with EAMs. A horizontal anaerobic digester (HAD) operated for 430 days as a testbed to validate the benefits of bioaugmentation with EAMs. Anaerobic digestate slurry, discharged from the HAD, was enriched with EAMs in a bioelectrochemical auxiliary reactor (BEAR) under an electric field. This slurry enriched with EAMs was then recirculated into the HAD. Results showed bio-augmentation with EAMs led to an increase in volatile solids removal from 56.2% to 77.5%, methane production rate from 0.59 to 1.00 L/L.d, methane yield from 0.26 to 0.34 L/g CODr, and biogas methane content from 59.9% to 71.6%. It suggests that bio-augmentation enhances DIET, promoting the conversion of volatile fatty acids to methane and enhancing resilience against kinetic imbalances. The enrichment of EAMs reached optimal efficacy under an electric field intensity of 2.07 V/cm with a mean exposure time of 2.53 days to the electric field in the BEAR. Bio-augmentation with externally enriched EAMs is a feasible and effective strategy to optimize anaerobic digestion processes.
Kenji Kiyohara, Takushi Sugino, Kinji Asaka
Advances in Science and Technology · 2008
In order to understand the mechanism of the bending motion of the electroactive polymer actuators from the molecular interaction, we performed Monte Carlo simulations in two length scales; the micrometer scale and the nanometer scale. In the micrometer scale picture, the bending motion of an actuator can be viewed as the inhomogeneous expansion/contraction of the three layer system. We theoretically formulated the deformation of the actuator in terms of the elastic constants and the stress exerted due to the applied voltage. For the nanometer scale, noting that the electrodes of the EAP actuators have porous structures, we modeled the anode and the cathode by the porous electrodes where the ions are confined in the space with the dimension comparable to the ion size. We found that significant osmotic stress arises in the porous electrodes when voltage is applied. The results of such multi-scale analyses are combined with the experimental results to obtain the insights into the molecular mechanism of the actuators and to give the guideline for the molecular design of the actuators.
Mirian Samblas, J. Alfredo Martínez, Fermín Milagro
Mediators of Inflammation · 2018
DNA methylation has been suggested as a regulatory mechanism behind some inflammatory processes. The physiological actions of methyl donors, such as folic acid, choline, and vitamin B 12 on inflammation-related disease have been associated with the synthesis of the universal methyl donor S-adenosyl methionine (SAM). The aim of this study was to evaluate the effects of folic acid, choline, vitamin B 12 , and a combination of all on preventing the lipopolysaccharide- (LPS-) induced inflammatory response in human THP-1 monocyte/macrophage cells. Folic acid and the mixture of methyl donors reduced interleukin 1 beta (IL1B) and tumour necrosis factor (TNF) expression as well as protein secretion by these cells. Folic acid and choline decreased C-C motif chemokine ligand 2 ( CCL2 ) mRNA levels. In addition to this, the methyl donor mixture reduced Cluster of differentiation 40 (CD40) expression, but increased serpin family E member 1 (SERPINE1) expression. All methyl donors increased methylation levels in CpGs located in IL1B , SERPINE1 , and interleukin 18 (IL18) genes. However, TNF methylation was not modified. After treatment with folic acid and the methyl donor mixture, ChIP analysis showed no change in the binding affinity of nuclear factor- κ B (NF- κ B) to IL1B and TNF promoter regions after the treatment with folic acid and the methyl donor mixture. The findings of this study suggest that folic acid might contribute to the control of chronic inflammation in inflammatory-related disease.
Boyeth Pelone, Patricia Ann Sanchez
International Journal of Built Environment and Sustainability · 2025
Amid escalating climate change and other factors, communities in vulnerable areas like Tagum City, Davao del Norte, Philippines, face increasing risks of severe flooding, threatening their safety, livelihoods, and well-being. This highlights the urgent need for comprehensive analysis of flood dynamics and community resilience within a social-ecological system framework, addressing the critical gap in local-level research to inform effective flood risk management strategies. This study employed a combined systematic literature review, Fuzzy Delphi Method, and Analytical Hierarchy Process to develop a Flood Resilience Index (FRI) and resilience map using QGIS. The findings underscore that a significant portion of Tagum City exhibits medium resilience to flooding, with an FRI of 3.221. Notably, several towns identified as medium resilient, including Bincungan (2.801), Pandapan (2.661), Busaon (2.910), and Liboganon (2.660), face heightened vulnerability due to the potential for high flood water levels, exceeding critical thresholds, with a peak level of 11 meters for a projected 5-year return period. The study highlights the interconnectedness of social-ecological components, emphasizing that overall system resilience depends on its weakest elements. To enhance resilience in flood-vulnerable areas, it is crucial to strengthen economic, institutional, and socio-cultural support systems through targeted activities, policies and programs. This research provides crucial insights into the intricate relationship between flooding and resilience, serving as a foundation for informed decision-making and proactive measures to mitigate flood risks, enhance community well-being, and advance climate action for a more resilient and sustainable Tagum City and similar environments.
Yi Wu, Claire Flemmer
International Journal of Built Environment and Sustainability · 2020
Glass curtain wall provides an attractive building envelope, but it is generally regarded as unsustainable because of the high energy needed to maintain thermal comfort. This research explores the advances in the technology of glass cladding and the complex issues associated with judging its sustainability. It assesses the technology and sustainability of glass curtain wall on a sample of thirty commercial buildings in Auckland, New Zealand. Field observations of the glass-clad buildings, coupled with surveys of the building occupants and of glass cladding professionals are used to investigate the cladding characteristics, operational performance, sustainability aspects and future trends. The majority of the sample buildings are low-rise office buildings. The occupants like the aesthetics and indoor environment quality of their glass-clad buildings. However, continuous heating, ventilation and air conditioning are needed in order to maintain thermal comfort within the buildings and this has high energy consumption. The increasing use of unitized systems with double glazing instead of stick-built systems with single glazing improves the sustainability of the cladding through less material wastage and better energy efficiency. Inclusion of photovoltaic modules in the curtain wall also improves energy efficiency but it is currently too expensive for use in New Zealand. Environmental sustainability is also improved when factors such as climate, the orientation of glazed façades, solar control, ventilation and the interior building layout are considered. Any assessment of glass curtain wall sustainability needs to consider the economic and social aspects as well as the environmental aspects such as energy use
Taniela Marli Bes, Marina Cortês Farrel, Carlos Santos et al.
medRxiv · 2022
Abstract Antimicrobial resistance has grown exponentially in the last decade and become a global health threat. The antibiotic resistance crisis has guided the scientific community to explore non-conventional interventions to target resistant bacteria. Development of new technologies, such as aptamers-based treatment and diagnosis, has shown to be promising with remarkable advantages over the past five years. This narrative review aims on what is already known regarding application of aptamer technology in enterobacteria and non-fermenters, and the prospects for future achievements. A systematic search of the English literature was performed on the 7th of December 2021 to identify papers on aptamer discovery, with a focus on gram negative isolates, published from January 01, 1993, to December 07, 2021, under the topics: (aptamer OR aptamers OR SELEX) AND (bacteria OR sepsis OR non-fermenter OR Enterobacteriaceae OR infection)). The reference lists of included articles were also searched, in addition to hand-searching of various relevant high-impact journals. Out of 2,474 articles, 30 experimental studies were recruited for review, and are chronologically described. Although the number of publications regarding development of aptamers to target these pathogenic agents has increased over the years, the recent publications are mostly around diagnostic devices manufactured using previously described aptamers. There have been less than one-third of the studies describing new and specific aptamers. From the 30 selected papers, 18 are regarding non-fermenters, seven approaching multi-species of bacteria and only five regarding a single enterobacteria. Even for the newly described aptamers, most of the published papers pertain to diagnostic aptamers and only seven focus on aptamers for therapeutics. The number of aptamers with strong and specific binding capacity are still limited. Improving the current SELEX and developing more APT remains the major hurdle for aptamer related studies.
Mireia Saladrigas-García, Mario Durán, Matilde D’Angelo et al.
Animal Microbiome · 2022
Abstract Background The establishment of the gut microbiota can be influenced by several perinatal factors, including, most importantly, the maternal microbiota. Moreover, early-life environmental variation affects gut microbial colonization and the intestinal health of offspring throughout life. The present study aimed to explore the development of piglet gut microbiota from birth to weaning in the commercial practice and also to assess how different farm environments could condition this process. Although it is possible to find in the literature other studies with similar objectives this work probably represents one of the few studies that make a systematic evaluation of such differential factors under a real scenario. To achieve this objective, we performed two trials. In a first Trial, we selected 2 farms in which we performed an intensive sampling (5 samples /animal) to characterize the gut colonization pattern during the first days of life and to identify the time window with the greatest impact. Both farms differed in their health status and the use of antimicrobials in the piglets. In a second Trial, we selected 4 additional farms with variable rearing conditions and a distinctive use of antimicrobials in the sows with a simplified sampling pattern (2 samples/animal). Faecal samples were obtained with swabs and DNA was extracted by using the PSP® Spin Stool DNA Kit and sequencing of the 16S rRNA gene (V3-V4 region) performed by Illumina MiSeq Platform. Results The present study contributes to a better understanding of microbiome development during the transition from birth to weaning in commercial conditions. Alpha diversity was strongly affected by age, with an increased richness of species through time. Beta diversity decreased after weaning, suggesting a convergent evolvement among individuals. We pinpointed the early intestinal colonizers belonging to Bacteroides, Escherichia-Shigella , Clostridium sensu stricto 1, and Fusobacterium genera. During lactation(d7-d21 of life), the higher relative abundances of Bacteroides and Lactobacillus genera were correlated with a milk-oriented microbiome. As the piglets aged and after weaning (d36 of life), increasing abundances of genera such as Prevotella , Butyricimonas , Christensenellaceae R-7 group , Dorea , Phascolarctobacterium , Rikenellaceae RC9 gut group , Subdoligranulum, and Ruminococcaceae UCG-002 were observed. These changes indicate the adaptation of the piglets to a cereal-based diet rich in oligosaccharides and starch. Our results also show that the farm can have a significant impact in such a process, evidencing the influence of different environments and rearing systems on the gut microbiota development of the young piglet. Differences between farms were more noticeable after weaning than during lactation with changes in alpha and beta biodiversity and specific taxa. The analysis of such differences suggests that piglets receiving intramuscular amoxicillin (days 2–5 of life) and being offered an acidifying rehydrating solution (Alpha farm in Trial 1) have a greater alpha diversity and more abundant Lactobacillus population. Moreover, the only farm that did not offer any rehydrating solution (Foxtrot farm in Trial 2) showed a lower alpha diversity (day 2 of life) and increased abundance of Enterobacteriaceae (both at 2 and 21 days). The use of in-feed antibiotics in the sows was also associated with structural changes in the piglets’ gut ecosystem although without changes in richness or diversity. Significant shifts could be registered in different microbial groups, particularly lower abundances of Fusobacterium in those piglets from medicated sows. Conclusions In conclusion, during the first weeks of life, the pig microbiota showed a relevant succession of microbial groups towards a more homogeneous and stable ecosystem better adapted to the solid dry feed. In this relevant early-age process, the rearing conditions, the farm environment, and particularly the antimicrobial use in piglets and mothers determine changes that could have a relevant impact on gut microbiota maturation. More research is needed to elucidate the relative impact of these farm-induced early life-long changes in the growing pig.
Miguel Angel Martínez, Ana Jordan-Paiz, Sandra Franco et al.
Nucleic Acids Research · 2019
Abstract Synthetic genome recoding is a new means of generating designed organisms with altered phenotypes. Synonymous mutations introduced into the protein coding region tolerate modifications in DNA or mRNA without modifying the encoded proteins. Synonymous genome-wide recoding has allowed the synthetic generation of different small-genome viruses with modified phenotypes and biological properties. Recently, a decreased cost of chemically synthesizing DNA and improved methods for assembling DNA fragments (e.g. lambda red recombination and CRISPR-based editing) have enabled the construction of an Escherichia coli variant with a 4-Mb synthetic synonymously recoded genome with a reduced number of sense codons (n = 59) encoding the 20 canonical amino acids. Synonymous genome recoding is increasing our knowledge of microbial interactions with innate immune responses, identifying functional genome structures, and strategically ameliorating cis-inhibitory signaling sequences related to splicing, replication (in eukaryotes), and complex microbe functions, unraveling the relevance of codon usage for the temporal regulation of gene expression and the microbe mutant spectrum and adaptability. New biotechnological and therapeutic applications of this methodology can easily be envisaged. In this review, we discuss how synonymous genome recoding may impact our knowledge of microbial biology and the development of new and better therapeutic methodologies.
Silvia Monroy, Aitor Larrañaga, Aingeru Martínez et al.
Microbial Ecology · 2023
Abstract Ongoing global warming is expected to alter temperature-dependent processes. Nevertheless, how co-occurring local drivers will influence temperature sensitivity of plant litter decomposition in lotic ecosystems remains uncertain. Here, we examined the temperature sensitivity of microbial-mediated decomposition, microbial respiration, fungal biomass and leaf nutrients of two plant species varying in litter quality. We also assessed whether the type of microbial community and stream water characteristics influence such responses to temperature. We incubated alder ( Alnus glutinosa ) and eucalypt ( Eucalyptus globulus ) litter discs in three streams differing in autumn–winter water temperature (range 4.6–8.9 °C). Simultaneously, in laboratory microcosms, litter discs microbially conditioned in these streams were incubated at 5, 10 and 15 °C with water from the conditioning stream and with a water control from an additional stream. Both in the field and in the laboratory, higher temperatures enhanced litter decomposition rates, except for eucalypt in the field. Leaf quality modified the response of decomposition to temperature in the field, with eucalypt leaf litter showing a lower increase, whereas it did not in the laboratory. The origin of microbial community only affected the decomposition rates in the laboratory, but it did not modify the response to temperature. Water quality only defined the phosphorus content of the leaf litter or the fungal biomass, but it did not modify the response to temperature. Our results suggest that the acceleration in decomposition by global warming will be shaped by local factors, mainly by leaf litter quality, in headwater streams.
Ana Mellado, Lourdes Morillas, Antonio Gallardo et al.
New Phytologist · 2016
Summary Parasitic plants are important drivers of community and ecosystem properties. In this study, we identify different mechanisms by which mistletoe ( Viscum album subsp. austriacum ) can affect soil chemical and biological properties at different temporal stages of parasitism. We quantified the effect of parasitism on host growth and the number of frugivorous mutualists visiting the host canopy. Then we collected, identified, and weighed the organic matter input underneath tree canopies and analyzed its nutrient content. Simultaneously, we analyzed soil samples under tree canopies and examined the chemical properties, microbial abundance, and functional evenness of heterotrophic microbial communities. Mistletoe increased the amount, quality, and diversity of organic matter input beneath the host canopy, directly through its nutrient‐rich litter and indirectly through a reduction in host litterfall and an increase in bird‐derived debris. All these effects gave rise to enriched hotspots able to support larger and more functionally even soil microbial communities beneath parasitized hosts, the effects of which were accentuated after host death. We conclude that mistletoe, together with the biotic interactions it mediates, plays a key role in intensifying soil resource availability, regulating the functional evenness, abundance, and spatial distribution of soil microbial communities.
Elsa Fuentes, Rafael Carballeira, Beatriz Prieto
Applied Sciences · 2021
Local granite has been used throughout history in Galicia (NW Spain), forming the basis of much of the region’s architecture. Like any other rock, granite provides an ecological niche for a multitude of organisms that form biofilms that can affect the physical integrity of the stone. In this study, for the first time, characterization of the microbial consortium forming biofilms that developed on historical rural granite buildings is carried out using a combination of culture-dependent and next generation sequencing (NGS) techniques. Results pointed to differences in biofilm composition on the studied rural granite buildings and that of previously analyzed urban granite buildings, especially in terms of abundance of cyanobacteria and lichenized fungi. Exposure was corroborated as an important factor, controlling both the diversity and abundance of microorganisms on walls, with environmental factors associated with a northern orientation favoring a higher diversity of fungi and green algae, and environmental factors associated with the west orientation determining the abundance of lichenized fungi. The orientation also affected the distribution of green algae, with one of the two most abundant species, Trentepohlia cf. umbrina, colonizing north-facing walls, while the other, Desmococcus olivaceus, predominated on west-facing walls.
John Varcoe, Claudio Avignone-Rossa, Robert CT Slade
ECS Meeting Abstracts · 2014
Microbial fuel cell (MFC) technology is under development for electricity production for cleansing of waste waters, but also for direct use of the electricity in bio-electrochemical systems (BES) geared to produce high added value products (e.g. acetate and other complex organics from CO 2 ). The presentation will detail systematic examination of the chemical and biological variables in such systems. Both cation and anion exchange membranes of a range of controlled thickness as anode compartment and air cathode separator membrane will be outlined, with the accompanying variations in performance of otherwise similar cells. Both types of membrane can be readily tailored by their production using radiation-induced grafting of appropriately functionalized precursors and subsequent conversion to ionic head groups with accompanying ion-exchange properties. From extensive studies of a range of closely related MFCs, the role of variations in the composition of anode biofilms in operational MFCs have been characterized and compared to the population in suspension [1]. Film composition has been followed using DDGE, identifying the range of microbes present and variations in film composition during operation. Diversity of the community has been found to correlate with cell performance, and hence can be used as a predictor of cell behavior [2]. Identification of the make-up of microbial communities in operating MFCs has led to studies of the electrogenic activities of individual strains, and of their interactions when more than one species is present, detecting synergistic or antagonistic relationships. Data on microbial oxidative activity (metabolic profiling) using a range of substrates and a Biolog instrument (multi-well UV-vis spectrometer) have characterized the behaviors of a range of species (e.g. C. denitrificans and B. graminisolvens ) not normally considered of significance for power production in MFCs, both as single strains and in combination. “Synthetic communities” derived from these studies are indeed active in production of electricity in MFCs, with product analysis carried out by ion chromatography. A basic outline of the proposed metabolic profile of a synthetic community has been proposed, with individual species being classified as fermentative or electrogenic. The presence of fermentative species may lead to higher power output, contrary to previous orthodoxy. The potential for use of a complex waste (distiller’s dried grains with solubles, DDGS) for production of electricity or in the bio-electrochemical production of high added value products is also under investigation, with useable power densities being achieved Acknowledgements The UK’s SUPERGEN Biological Fuel Cells Consortium (8 univeristies) is led by RS and is funded by Research Councils UK (RCUK) under EPSRC grant EP/H019480/1 . Further work in MFC science at Surrey is funded by RCUK under EPSRC grant EP/I004882/1 and BBSRC grant BB/J01916X/1. References [1] N Beecroft, F Zhao, JR Varcoe, RCT Slade, A Thumser, C. Avignone-Rossa. Dynamic changes in the microbial community composition in microbial fuel cells fed with sucrose. Appl Microbiol Biotechnol. 93 , 423 – 437 (2012). [2] J.P. Stratford, N.J. Beecroft, R.C.T. Slade, A. Gruning, C. Avignone-Rossa. Anodic microbial community diversity as a predictor of the power output of microbial fule cells. Bioresource Technol. 156 , 84-91 (2014).
Miguel Mejias‐Ortiz, Ana Mencher, Pilar Morales et al.
Microbial Biotechnology · 2023
Abstract The recent introduction of non‐conventional yeast species as companion wine starters has prompted a growing interest in microbial interactions during wine fermentation. There is evidence of interactions through interference and exploitation competition, as well as interactions depending on physical contact. Furthermore, the results of some transcriptomic analyses suggest interspecific communication, but the molecules or biological structures involved in recognition are not well understood. In this work, we explored extracellular vesicles (EVs) as possible mediators of interspecific communication between wine yeasts. The transcriptomic response of Saccharomyces cerevisiae after 3 h of contact with a fraction enriched in EVs of Metschnikowia pulcherrima was compared with that induced by active M . pulcherrima cells. Interestingly, there is a high level of overlap between the transcriptomic profiles of yeast cells challenged by either M . pulcherrima whole cells or the EV‐enriched fraction. The results indicate an upregulation of yeast metabolism in response to competing species (in line with previous results). This finding points to the presence of a signal, in the EV‐enriched fraction, that can be perceived by the yeast cells as a cue for the presence of competitors, even in the absence of metabolically active cells of the other species.
Tatsuo Yagishita, Rinako Miyano, Kenichiro Tsukahara et al.
Solar Energy · 2003
The Effect of glucose addition on the current outputs of the electrochemical cells using Synechocystis sp. PCC6714 was investigated under the conditions with or without light. The current outputs increased with higher concentrations of HNQ and glucose. The current under illumination was lower than that in the dark even in the presence of 5 mM HNQ and 1 g 1−1 glucose, or 1 mM HNQ and 10 g 1−1 glucose. However, the coulombic output obtained from integration of the current was higher under illumination than in the dark under the conditions with 5 mM HNQ and 10 g 1−1 glucose. A main organic acid produced during discharge was acetic acid. The amount of acetic acid decreased, when the current outputs increased. Therefore, the current output production might compete with the production of acetic acid. Efficient system could be established by supplying both solar energy and chemical energy simultaneously.
Max Hackbarth, Tobias Jung, Johannes Eberhard Reiner et al.
· 2020
<p>In the last 40 years, bioelectrochemical systems (BESs) have been increasingly discussed within the scope of debates about sustainable energy sources and production of value added chemicals independent of fossil sources. Since the produced current in microbial fuel cells as well as the turnover rates in microbial electrosynthesis cells are dependent on the biocatalysts´ activity, control of the growing biofilm plays a major role in BESs. Moreover, the knowledge about the interplay between biofilm development and electrochemical parameters is crucial for optimizing these sytems.</p> <p>In the last 3 years, various electroactive biofilms (anodic and cathodic) were cultivated and characterized in a versatile and house made lab-scale flow cell system as well as in a rotating disc biofilm contactor (RDBC). Both systems allow for control of substrate (liquid and gaseous), and nutritional conditions as well as hydrodynamics and other physical parameters. The monitoring of biofilm development was conducted non-invasively by means of optical coherence tomography (OCT). For cathodic biofilms, quantitative analysis of generated 3D OCT data sets revealed a correlation between substratum coverage and measured current density. The increase of substratum coverage led to a decrease of measured current density due to less abiotic redox processes on the cathode surface. A stable current density was achieved when a substratum coverage of 99 % was reached. Furthermore, calculated biofilm accumulation rates could also be correlated with the substratum coverage. The overall biofilm accumulation rate decreased when the substratum was fully covered. Both correlations support the hypothesis that the availability of electrons from the cathode surface is a limiting factor in microbial electrosynthesis.</p> <p>A 10-liter RDBC was designed to continuously harvest biomass from the electrode to extract intracellularly stored products. In future, this approach could be applied for biotechnological processes. Additionally, the RDBC can be used to obtain reliable mass balances and turnover rates because of its larger scale.</p>
Rusul M. Khazaal, Zainab Z. Ismail
Journal of Petroleum Research and Studies · 2020
In this study, a steady-state bioelectrochemical model was developed to simulate thecorrelation between the acting overpotential and the produced current that is accounting foranode polarization. This study aimed to analyze the performance of a dual-chamberedmicrobial fuel cell (MFC) equipped with two bio-anodes and fueled with real refinery oilysludge having a COD concentration of 13890 mg /L. Anode polarization data revealed amaximum current density of 6.07 A/m3 of the substrate at an overpotential of 1.83 V. Inaddition, the behavior of the experimental measurements revealed the dominance of theohmic losses in the overall anode overpotential compared to activation and mass transferlosses, respectively. On the other hand, the suggested mathematical model was verifiedsignificantly by the obtained experimental data, achieving a determination coefficient (R2)of 0.96. Actual sustainable energy was also obtained using the reductive decrease of anodepotential (RDAP) and it was found that the sustainable energy for this correspondingsystem can be attained when applying 17.6 KΩ as the external resistor.
Hanyu Tang, McKenzie Burns, Mohan Qin
Environmental Science: Water Research & Technology · 2024
The impact of ion competition on nitrate removal from contaminated groundwater using membrane-based bioelectrochemical systems is investigated.
Marta Fernández Gatell
· 2024
(English) Freshwater is an extremely scarce yet essential resource for all life forms on planet Earth. Its quality directly impacts the development of human societies as well as the ecosystems balance and health. However, the main causes of freshwater and, consequently, environmental pollution are related to human activities such as agriculture, land use changes or poor water treatment. Therefore, proper treatment of wastewater before disposal is crucial for preserving the quality of the receiving natural environment. Furthermore, the importance of the metabolic activity of microorganisms in both the natural environment and wastewater treatment systems shall be highlighted as they govern the biogeochemical cycles. Indeed, microbial activity is considered as good environmental quality indicator. Given the actual water emergency situation, techniques allowing for fast and efficient monitoring and control of parameters/indicators related to water quality and microbial activity in ecosystems are required. The use of sensors and biosensors might be a good strategy to achieve this goal. Bioelectrochemical systems (BES) are devices capable of generating a small electric current driven by the metabolic activity of electroactive microorganisms. BES, among many other uses, have also been applied as biosensors, for assessing organic substrates and toxic compounds. Therefore, the main objective of this Thesis is to assess the feasibility of using bioelectrochemical systems (BES) for efficient water resources monitoring and control. More specifically, to determine the potential of various types of BES for estimating parameters related to both water quality and the activity of microbial populations inhabiting a given ecosystem. Constructed wetlands (or treatment wetlands, TW) are natural wastewater treatment systems that have been used as a context environment throughout the present Thesis. The results obtained in the first part of the Thesis demonstrate that the implementation of BES in treatment wetlands increases the enzymatic and aerobic activity of the microbial communities, which in turn is related to a better treatment efficiency of these systems compared to conventional ones, i.e., without BES. Subsequently, in the second part, the applicability of different bioelectrochemical systems as biosensors for microbial activity and water quality was evaluated. Regarding the use of MFCs and M3Cs as biosensors, the experiments indicate that both systems can be used to estimate microbial activity and organic matter concentration. Specifically, the parameters that can be estimated with better precision are ATP content and organic matter concentration (measured as chemical oxygen demand, COD), although good results have also been achieved for biomass (measured as volatile solids, VS) and enzymatic activity biosensing. In addition, M3Cs offer better stability, precision, and sensor lifespan compared to MFC ones. Furthermore, the use of current peaks generated during the discontinuous operation of the BES offers better results in terms of sensitivity and precision compared to continuous signal, although information processing is more tedious. Demonstrating that the discontinuous operation of BES is also useful as a biosensing tool allows for widening their applicability to environments in which water saturation conditions are met intermittently. Finally, from the study conducted in a full-scale treatment plant where several MFCs were implemented and used as biosensors, it is found that the BES scaling up is traduced in a decrease of sensor’s precision. However, it allows to determine not only microbial activity and organic matter concentration but also the clogging state of the treatment bed and its hydraulic conductivity. In conclusion, although still in its investigation infancy, bioelectrochemical systems-based biosensors can be used as a holistic monitoring system, at least in water treatment systems, for improving water management and control. (Català) L'aigua dolça disponible és un bé extremadament escàs però essencial per a qualsevol forma de vida a la Terra. La seva qualitat impacta directament en les poblacions humanes i en la salut i equilibri dels ecosistemes. Malgrat tot, la principal causa de la seva contaminació i, en conseqüència, de la dels ecosistemes naturals, és l'activitat humana. És evident, doncs, que el sanejament adequat de l'aigua residual abans de ser abocada al medi receptor és de capital importància per preservar-ne la qualitat i salut. Per altra banda, l'activitat metabòlica dels microorganismes que habiten tant ambients naturals com els sistemes de sanejament d'aigua és també crucial. De fet, l'activitat microbiana es considera un bon indicador de la qualitat d'un ecosistema. Per tot això, i donada l'actual situació d'emergència hídrica, es requereix de tècniques que permetin un monitoratge i control ràpids i eficients dels paràmetres relacionats amb la qualitat de l'aigua i l'activitat microbiana dels ecosistemes. L'ús de sensors i biosensors pot ser una bona estratègia per aconseguir-ho. En aquest sentit, els sistemes bioelectroquímics (BES, per les seves sigles en anglès) són instruments capaços de generar un petit corrent elèctric gràcies al metabolisme dels microorganismes electroactius, que, entre molts altres usos, s'han aplicat també com a biosensors. Així doncs, l'objectiu principal d'aquesta Tesi és avaluar la viabilitat dels sistemes bioelectroquímics per a un millor monitoratge i control dels recursos hídrics. Concretament, es pretén determinar el potencial de diversos tipus de BES per a l'estimació de paràmetres relacionats amb la qualitat de l'aigua i amb l'activitat microbiana de les poblacions que habiten un ecosistema. Els aiguamolls construïts (o de tractament) són sistemes naturals de tractament d'aigua residual que s'han utilitzat com a sistema de context en aquesta Tesi. Els resultats obtinguts en la primera part de la Tesi demostren que la implementació de BES en aiguamolls construïts incrementa l'activitat enzimàtica i la respiració aeròbica de les comunitats bacterianes, la qual cosa, al seu torn, està relacionada amb una major eficiència de tractament d'aquests sistemes en comparació als convencionals. En la segona part de la Tesi, s'ha avaluat l'ús de diferents BES com a biosensors de l'activitat microbiana i de la qualitat de l'aigua. Els resultats obtinguts demostren l'aplicabilitat de MFCs i M3Cs com a biosensors per a aquesta finalitat. Concretament, els paràmetres que es poden estimar amb més precisió són el contingut d'ATP i la concentració de matèria orgànica, tot i que els resultats també són molt bons per a la biosensorització de la biomassa i de l'activitat enzimàtica. A més, les M3C ofereixen millor estabilitat, precisió i vida útil en comparació a les MFC. Per altra banda, l'ús dels pics de corrent que es generen en l'operació en discontinu d'un BES proporciona més sensibilitat i precisió en comparació al corrent en continu tot i l'augment en el processament d'informació. Demostrar que l'operació en discontinu dels BES és igualment útil com a eina de biosensorització permet ampliar l'aplicabilitat d'aquests biosensors a ambients que estan saturats d'aigua de manera intermitent. Finalment, s'ha estudiat l'ús de MFCs com a biosensors en una planta de tractament d'escala real. D'aquest estudi se'n conclou que l'increment de la dimensió del biosensor provoca una disminució de la precisió d'aquest. Malgrat això, permet determinar no només l'activitat microbiana i la concentració de matèria orgànica, sinó també la colmatació del llit de tractament i la seva conductivitat hidràulica. En conclusió, i malgrat que encara es trobi en un estat incipient de desenvolupament, els biosensors basats en sistemes bioelectroquímics poden utilitzar-se com a sistema de monitoratge i control holístics, almenys en sistemes de tractament, per a la millora de la gestió de l'aigua. (Español) El agua dulce disponible es un bien extremamente escaso pero esencial para cualquier forma de vida en la Tierra. Su calidad impacta directamente en las poblaciones humanas y en la salud y equilibrio de los ecosistemas. La principal causa de su contaminación, y, en consecuencia, de la de los ecosistemas naturales, es la actividad humana. Es evidente, pues, que el adecuado tratamiento del agua residual antes de su disposición al medio es de capital importancia para preservar su calidad y salud. Por otro lado, la actividad metabólica de los microorganismos tanto en el ambiente natural como en los sistemas de saneamiento del agua es también crucial. De hecho, la actividad microbiana se considera un buen indicador de la calidad de un ecosistema. Por lo expuesto, y dada la actual situación de emergencia hídrica, se requiere de técnicas que permitan un monitoreo y control rápidos y eficientes de los parámetros relacionados con la calidad del agua y la actividad microbiana de los ecosistemas. El uso de sensores y biosensores puede ser una buena estrategia para conseguirlo. En este sentido, los sistemas bioelectroquímicos (BES, por sus siglas en inglés) son instrumentos capaces de generar una corriente eléctrica gracias al metabolismo de los microorganismos electroactivos, que, entre muchos otros usos, se han aplicado también como biosensores. Así pues, el principal objetivo de esta Tesis es evaluar la viabilidad de los sistemas bioelectroquímicos para un mejor monitoreo y control de los recursos hídricos. Concretamente, se pretende determinar el potencial de varios tipos de BES para la estimación de parámetros relacionados con la calidad del agua y con la actividad microbianas de las poblaciones que habitan un ecosistema. Los humedales artificiales (o de tratamiento) son sistemas naturales de tratamiento de aguas residuales que se han usado como sistema de contexto en esta Tesis. Los resultados obtenidos en la primera parte de la Tesis demuestran que la implementación de BES en humedales artificiales incrementa la actividad enzimática y la respiración aeróbica de las comunidades microbianas, lo que, a su vez, está relacionado con una mayor eficiencia de tratamiento de estos sistemas en comparación con los convencionales. En la segunda parte de la Tesis, se ha evaluado el uso de diferentes BES como biosensores de la actividad microbiana y de la calidad del agua. Los resultados obtenidos demuestran la capacidad de MFCs y M3Cs como biosensores para este propósito. Concretamente, los parámetros que se pueden estimar con más precisión son el contenido de ATP y la concentración de materia orgánica, aunque también se han obtenido buenos resultados para la biosensorización de la biomasa y de la actividad enzimática. Además, las M3C ofrecen mejor estabilidad, precisión y vida útil comparadas con las MFC. Por otro lado, el uso de los picos de corriente que se generan en la operación en discontinuo de un BES proporciona más sensibilidad y precisión en comparación con la corriente en continuo a expensas de un aumento del procesado de información. Demostrar que la operación en discontinuo de los BES es igualmente útil como herramienta de biosensorización, permite ampliar la aplicabilidad de estos biosensores a ambientes que están saturados de agua de manera intermitente. Finalmente, se ha estudiado el uso de MFCs como biosensores en una planta de tratamiento de escala real. De este estudio se concluye que el incremento de tamaño del sensor provoca una disminución de la precisión del mismo. A pesar de ello, permite determinar no solo la actividad microbiana y la concentración de materia orgánica, sino también la colmatación del lecho de tratamiento y su conductividad hidráulica. En conclusión, y aunque aún en un estado inicial de desarrollo, los biosensores basados en sistemas bioelectroquímiccos pueden usarse como sistema de monitorización y control holísticos, al menos en sistemas de tratamiento, para la mejora de la gestión del agua.
Kazuko Tanaka, Reita Tamamushi, Teruo Ogawa
Journal of Chemical Technology and Biotechnology. Biotechnology · 1985
Abstract Substantial electric output was delivered from the bioelectrochemical fuel‐cells operated under anaerobic conditions by Anabaena variabilis strain M‐2 and 2‐hydroxy‐1,4‐naphthoquinone. There was a linear relationship between the coulombic output of the fuel‐cells operated in the dark and the glycogen content of the organisms. The coulombic output was increased substantially in the light; the increase was observed even in the absence of CO 2 . Oxygen was evolved by Anabaena cells under the operating conditions of the fuel‐cells. The results demonstrated that the source of electricity obtained from the fuel‐cells is endogenous glycogen in the dark and both glycogen and electrons produced by photosynthetic oxidation of water in the light.
T. Thundat, L. A. Nagahara, P. Oden et al.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films · 1990
We have imaged DNA deposits that have been reacted onto a gold electrode. Our scanning tunneling microscope (STM) is operated in a three electrode cell using insulated tips. Samples are deposited at a controlled potential relative to an Ag/AgCl reference electrode. Many different adsorption geometries are observed, different substrate potentials resulting in characteristic adsorption patterns. Here, we report initial results for negative electrodes. At −2.3 V (Ag/AgCl), the DNA appears to attach to the substrate end on. As the potential is lowered towards zero volts, the DNA attaches side on, forming aggregates of decreasing complexity with decreasing substrate potential. Isolated molecules are observed near −1 V (Ag/AgCl). Below this potential, coverage is much less dense. Those molecules that adsorb do so in aggregates, which may bind in alignment with the underlying atomic structure of the substrate.
Francisco Jesus Fernandez-Morales, Yelitza Delgado, Ester Lopez et al.
Global NEST International Conference on Environmental Science & Technology · 2023
This work presents a Monod-based mathematical model able to predict the performance of a bioelectrochemical system (BES) treating Acid Mine Drainage (AMD). The BES was operated as a microbial fuel cell (MFC), in order to recover not only the metals but also all the chemical energy contained. The model was based on two different microbial populations performing electrogenic and non-electrogenic metabolisms respectively. During the MFC operation the metal contained in the AMD were the electron acceptors at the cathode. Because of that, Cu2+ and Fe3+ were reduced to Cu0 and Fe2+. The model formulation was based on a set of differential equations describing the simultaneous evolution of the main chemical components in the system. The model developed accurately predicted the concentration of the acetate and biomass at the anode, the metals at the cathode as well as the electrical current generated.
Xi Chen, Dongya Sun, Xiaoyuan Zhang et al.
Scientific Reports · 2015
Conventional wastewater purification technologies consume large amounts of energy, while the abundant chemical energy and nutrient resources contained in sewage are wasted in such treatment processes. A microbial nutrient recovery cell (MNRC) has been developed to take advantage of the energy contained in wastewater, in order to simultaneously purify wastewater and recover nutrient ions. When wastewater was circulated between the anode and cathode chambers of the MNRC, the organics (COD) were removed by bacteria while ammonium and phosphate (NH₄⁺-N and PO₄³⁻-P) were recovered by the electrical field that was produced using in situ energy in the wastewater without additional energy input. The removal efficiencies from wastewater were >82% for COD, >96% for NH₄⁺-N, and >64% for PO₄³⁻-P in all the operational cycles. Simultaneously, the concentrations of NH₄⁺ and PO₄³⁻ in the recovery chamber increased to more than 1.5 and 2.2 times, respectively, compared with the initial concentrations in wastewater. The MNRC provides proof-of-concept as a sustainable, self-driven approach to efficient wastewater purification and nutrient recovery in a comprehensive bioelectrochemical system.
Yoong-Sin Oon, Yoong-Ling Oon, Muhammad Ayaz et al.
Communications Earth & Environment · 2025
Photosynthetic microbial fuel cells present an integrated strategy for wastewater treatment, greenhouse gas mitigation and bioenergy recovery. Here we elucidate the bioelectrochemical mechanisms by which external resistance and cathodic configuration regulate nitrogen transformation, carbon dynamics and microalgae-bacteria interactions. A microalgae-based cathode achieved net-negative carbon dioxide flux and approximately 37% lower nitrous oxide emissions than open-circuit systems, corresponding to reduced global warming potential relative to mixed-microbial and abiotic cathodes. This reflected enhanced carbon dioxide fixation and suppression of methane and nitrous oxide emissions. Nitrous oxide reduction in the anodic region was attributed to denitrifying bacteria expressing nitrous oxide reductase, supported by electrons from organic matter oxidation. Photosynthesis stimulated nitrification at the cathode, while microalgae assimilated nutrients, improving removal. Lower external resistance enhanced extracellular electron transfer, correlated with elevated pilA and OmcS gene abundance and enrichment of electrogenic genera including Shinella, Geobacter and Pseudomonas. These findings reveal integrated electrochemical–microbial mechanisms facilitating sustainable treatment. Bioelectrochemical interactions between microalgae and bacteria can improve extracellular electron transfer, nitrogen transformation and greenhouse gas mitigation during wastewater treatment in a photosynthetic microbial fuel cell.
Mohammed Mouhib, Melania Reggente, Lin Li et al.
bioRxiv (Cold Spring Harbor Laboratory) · 2021
Extracellular electron transfer (EET) engineering in Escherichia coli holds great potential for bioremediation, energy and electrosynthesis applications fueled by readily available organic substrates. Due to its vast metabolic capabilities and availability of synthetic biology tools to adapt strains to specific applications, E. coli is of advantage over native exoelectrogens, but limited in electron transfer rates. We enhanced EET in engineered strains through systematic expression of electron transfer pathways differing in cytochrome composition, localization and origin. While a hybrid pathway harboring components of an E. coli nitrate reductase and the Mtr complex from the exoelectrogen Shewanella oneidensis MR-1 enhanced EET, the highest efficiency was achieved by implementing the complete Mtr pathway from S. oneidensis MR1 in E. coli . We show periplasmic electron shuttling through overexpression of a small tetraheme cytochrome to be central to the electroactivity of this strain, leading to enhanced degradation of the pollutant methyl orange and significantly increased electrical current to graphite electrodes.
Xiaofang Yan, Danyang Liu, Johannes B. M. Klok et al.
Environmental Science & Technology · 2023
Bioelectrochemical systems (BESs) are considered to be energy-efficient to convert ammonium, which is present in wastewater. The application of BESs as a technology to treat wastewater on an industrial scale is hindered by the slow removal rate and lack of understanding of the underlying ammonium conversion pathways. This study shows ammonium oxidation rates up to 228 ± 0.4 g-N m–3 d–1 under microoxic conditions (dissolved oxygen at 0.02–0.2 mg-O2/L), which is a significant improvement compared to anoxic conditions (120 ± 21 g-N m–3 d–1). We found that this enhancement was related to the formation of hydroxylamine (NH2OH), which is rate limiting in ammonium oxidation by ammonia-oxidizing microorganisms. NH2OH was intermediate in both the absence and presence of oxygen. The dominant end-product of ammonium oxidation was dinitrogen gas, with about 75% conversion efficiency in the presence of a microoxic level of dissolved oxygen and 100% conversion efficiency in the absence of oxygen. This work elucidates the dominant pathways under microoxic and anoxic conditions which is a step toward the application of BESs for ammonium removal in wastewater treatment.
Abdullah Almatouq, Akintunde Babatunde
International Journal of Environmental Research and Public Health · 2016
This study investigated the mechanism and key factors influencing concurrent phosphorus (P) recovery and energy generation in microbial fuel cells (MFC) during wastewater treatment. Using a mediator-less dual chamber microbial fuel cell operated for 120 days; P was shown to precipitate as struvite when ammonium and magnesium chloride solutions were added to the cathode chamber. Monitoring data for chemical oxygen demand (COD), pH, oxidation reduction potential (ORP) and aeration flow rate showed that a maximum 38% P recovery was achieved; and this corresponds to 1.5 g/L, pH > 8, −550 ± 10 mV and 50 mL/min respectively, for COD, pHcathode, ORP and cathode aeration flow rate. More importantly, COD and aeration flow rate were shown to be the key influencing factors for the P recovery and energy generation. Results further show that the maximum P recovery corresponds to 72 mW/m2 power density. However, the energy generated at maximum P recovery was not the optimum; this shows that whilst P recovery and energy generation can be concurrently achieved in a microbial fuel cell, neither can be at the optimal value.