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C. Durante, L. Hegedüs, A. Czarniecka et al.
European Thyroid Journal · 2023
With the widespread use of sensitive imaging techniques, which include neck visualization, a conspicuous number of thyroid nodules emerge and demand attention. Most lesions are benign, asymptomatic, and do not warrant treatment. In the case of cancer diagnosis, most are small, intrathyroidal and indolent neoplasms that can safely be managed conservatively. There is a pronounced need for more cost-effective, risk-adapted approaches to the management of this highly prevalent condition, taking the wishes of the patient into consideration. Thus, the present guidelines aim at providing a clinical practice guide for the initial workup and the subsequent management of adult individuals harboring thyroid nodules. Importantly, these guidelines are not intended to cover the management of thyroid malignancy. The manuscript and the specific recommendations were developed by reconciling the best available research evidence with the knowledge and clinical experience of the panelists and updating aspects of a number of previous European Thyroid Association guidelines.
A. Timmis, P. Vardas, N. Townsend et al.
European Heart Journal · 2022
AIMS This report from the European Society of Cardiology (ESC) Atlas Project updates and expands upon the widely cited 2019 report in presenting cardiovascular disease (CVD) statistics for the 57 ESC member countries. METHODS AND RESULTS Statistics pertaining to 2019, or the latest available year, are presented. Data sources include the World Health Organization, the Institute for Health Metrics and Evaluation, the World Bank, and novel ESC sponsored data on human and capital infrastructure and cardiovascular healthcare delivery. New material in this report includes sociodemographic and environmental determinants of CVD, rheumatic heart disease, out-of-hospital cardiac arrest, left-sided valvular heart disease, the advocacy potential of these CVD statistics, and progress towards World Health Organization (WHO) 2025 targets for non-communicable diseases. Salient observations in this report: (i) Females born in ESC member countries in 2018 are expected to live 80.8 years and males 74.8 years. Life expectancy is longer in high income (81.6 years) compared with middle-income (74.2 years) countries. (ii) In 2018, high-income countries spent, on average, four times more on healthcare than middle-income countries. (iii) The median PM2.5 concentrations in 2019 were over twice as high in middle-income ESC member countries compared with high-income countries and exceeded the EU air quality standard in 14 countries, all middle-income. (iv) In 2016, more than one in five adults across the ESC member countries were obese with similar prevalence in high and low-income countries. The prevalence of obesity has more than doubled over the past 35 years. (v) The burden of CVD falls hardest on middle-income ESC member countries where estimated incidence rates are ∼30% higher compared with high-income countries. This is reflected in disability-adjusted life years due to CVD which are nearly four times as high in middle-income compared with high-income countries. (vi) The incidence of calcific aortic valve disease has increased seven-fold during the last 30 years, with age-standardized rates four times as high in high-income compared with middle-income countries. (vii) Although the total number of CVD deaths across all countries far exceeds the number of cancer deaths for both sexes, there are 15 ESC member countries in which cancer accounts for more deaths than CVD in males and five-member countries in which cancer accounts for more deaths than CVD in females. (viii) The under-resourced status of middle-income countries is associated with a severe procedural deficit compared with high-income countries in terms of coronary intervention, ablation procedures, device implantation, and cardiac surgical procedures. CONCLUSION Risk factors and unhealthy behaviours are potentially reversible, and this provides a huge opportunity to address the health inequalities across ESC member countries that are highlighted in this report. It seems clear, however, that efforts to seize this opportunity are falling short and present evidence suggests that most of the WHO NCD targets for 2025 are unlikely to be met across ESC member countries.
M. Fassnacht, S. Tsagarakis, M. Terzolo et al.
European Journal of Endocrinology · 2023
Adrenal incidentalomas are adrenal masses detected on imaging performed for reasons other than suspected adrenal disease. In most cases, adrenal incidentalomas are non-functioning adrenocortical adenomas, but may also require therapeutic intervention including that for adrenocortical carcinoma, pheochromocytoma, hormone-producing adenoma or metastases. Here, we provide a revision of the first international, interdisciplinary guidelines on incidentalomas. We followed the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system and updated systematic reviews on four predefined clinical questions crucial for the management of incidentalomas: A) How to assess risk of malignancy? ; B) How to define and manage mild autonomous cortisol secretion? ; C) Who should have surgical treatment and how should it be performed? ; D) What follow-up is indicated if the adrenal incidentaloma is not surgically removed? Selected Recommendations: 1) Each adrenal mass requires dedicated adrenal imaging. Recent advances now allow discrimination between risk categories: Homogeneous lesions with HU ≤ 10 on unenhanced CT are benign and do not require any additional imaging independent of size. All other patients should be discussed in a multidisciplinary expert meeting, but only lesions >4 cm that are inhomogeneous or have HU >20 have sufficiently high risk of malignancy that surgery will be the usual management of choice. 2) Every patient needs a thorough clinical and endocrine work-up to exclude hormone excess including the measurement of plasma or urinary metanephrines and a 1-mg overnight dexamethasone suppression test (applying a cutoff value of serum cortisol ≤50 nmol/l (≤1.8 µg/dl)). Recent studies have provided evidence that most patients without clinical signs of overt Cushing's syndrome but serum cortisol levels post dexamethasone >50 nmol/l (>1.8 µg/dl) harbor increased risk of morbidity and mortality. For this condition, we propose the term 'mild autonomous cortisol secretion' (MACS). 3) All patients with MACS should be screened for potential cortisol-related comorbidities that are potentially attributably to cortisol (e.g. hypertension and type 2 diabetes mellitus), to ensure these are appropriately treated. 4) In patients with MACS who also have relevant comorbidities surgical treatment should be considered in an individualized approach. 5) The appropriateness of surgical intervention should be guided by the likelihood of malignancy, the presence and degree of hormone excess, age, general health and patient preference. We provide guidance on which surgical approach should be considered for adrenal masses with radiological findings suspicious of malignancy. 6) Surgery is not usually indicated in patients with an asymptomatic, non-functioning unilateral adrenal mass and obvious benign features on imaging studies. Furthermore, we offer recommendations for the follow-up of non-operated patients, management of patients with bilateral incidentalomas, for patients with extra-adrenal malignancy and adrenal masses, and for young and elderly patients with adrenal incidentalomas. Finally, we suggest ten important research questions for the future.
D. Pant, Suman Bajracharya, Srikanth Sandipam et al.
Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1 · 2014
Background Increasing renewable electricity leads to moments of overproduction coupled to points in time for which not enough production is available to fulfill the needs. In a scenario of 100% renewable energy, about 20% of the yearly production will need to be stored to keep the system in balance. Since the Antwerp-Rotterdam-Rhine-Ruhr (ARRR) cluster is the European region where the highest CO2-emissions are measured (highest production, but also highest population density and energy supply), this region is well positioned to focus on CO2 and 'peak shaving' of renewable energy. Since it is also one of the biggest chemical clusters, the conversion of CO2 into new molecules makes sense guaranteeing that the final balance on energy use and CO2-emissions are lower than in the classical production. We have started an initiative to explore technologies for converting CO2, preferentially coupled to 'peak shaving', to building blocks for the chemical sector. Microbial Electrosynthesis Generation of electric current from the metabolism of organic substrates in microbial fuel cells (MFCs), using bacteria as electrocatalysts was reported. By converting the chemical energy stored in organic substrates to electricity, MFCs can reduce the operational cost of wastewater treatment plants. Recently, a new concept of microbial electrosynthesis has evolved where similar setups, generally known as bioelectrochemical systems (BES), are being used for the production of chemicals. Already the bioelectrochemical reduction of CO2 to acetate has been achieved, as well as the reduction of CO2 to methane and multi-carbon compounds. Efforts are underway to utilize a wide variety of substrates for production of an array of compounds. The key advantage here is the use of excess electricity that is often generated renewably, from solar cells and wind mills, all of which cannot be utilized immediately and can be fed into BES to produce chemicals. We will report our first results with specific bacteria towards bioelectrochemical conversion of CO2 to organic compounds. Acetogens like Sporomusa and Clostridium sps. were experimented for their CO2 reduction capacity at -0.6 V vs Ag/AgCl cathode potential. Adjustment of reduction potential and optimization of cell conditions were carried out in a fed batch reactor with an activated carbon cathode. Production of 67 mg/L ethanol with mixed culture as biocatalyst was the most remarkable achievement. Enzymatic Electrosynthesis Enzymes can also be used for chemical transformations including both the reduction and oxidation reactions. We are using CO2 as substrate for the production of methanol which will have a significant positive impact on environment as well as energy crisis. Electrosynthesis of formic acid was higher at an operational voltage of -1 V vs. Ag/AgCl (9.37 mg L-1 CO2) compared to operation at -0.8 V (4.73 mg L-1 CO2) which was strongly supported by the reduction catalytic current. Voltammograms also depicted a reversible redox peak throughout operation at -1 V, indicating NAD+ recycling for proton transfer from the source to CO2. Product saturation was observed after 45 minutes of enzyme addition and then reversibility commenced, depicting a lower and stable formic acid concentration throughout the subsequent time of operation.
Ayorinde Babatund Fasan, Oluwaseun A. Adelaja, J. Babatola et al.
Asian Journal of Biological Sciences · 2024
The erratic power supply in Nigeria has led to a decline in economic development and a low standard of living for many people within the country. Access to Nigeria’s electricity has been low for a very long time with no improvement in sight. One of the ways of resolving this problem is the provision of a microbial fuel cell (MFC) that can power some of the devices at home. This study investigates some of the electrochemical parameters of the electrolyte in microbial fuel cells. Three identical laboratory microbial fuel cells (MFCs) were constructed with a working volume of 1000 mL for each chamber. The MFCs were constructed in an H-shaped design with both chambers separated by cation ceramic membranes (CEM). Activated carbon materials obtained from white afara tree ( Terminalia superba (TS)), bamboo tree ( Bambusa vulgaris (BV)) and carbon cloth (CC) were used as the electrodes which were dipped into the reactors as MFC-1, MFC-2 and MFC-3, respectively. The electrochemical parameters of the electrolyte were studied. The maximum potential difference being obtained from MFC-1 ( Terminalia superba (TS)) and MFC-3 (carbon cloth (CC)) occurred on day 5 which were 0.510 V and 0.95 V, respectively. The maximum potential difference obtained from MFC-2 ( Bambusa vulgaris (BV)) occurred on day 15 which was 0.2 V. The results generated in this study showed that MFC-3 (carbon cloth (CC)) performed better in terms of voltage generation. The result of MFC-1 ( Terminalia superba (TS)) showed that it performed better than MFC-2 ( Bambusa vulgaris (BV) in terms of voltage generation. The results provide further information on the possibility of using MFCs for electricity generation.
J. Unuofin, S. Iwarere, M. Daramola
Environmental Science and Pollution Research · 2023
Sustainable development and energy security, highlighted by the United Nations Sustainable Development Goals (SDGs), necessitate the use of renewable and sustainable energy sources. However, upon careful evaluation of literature, we have discovered that many existing and emerging renewable energy systems (RESs) prioritize renewability over true sustainability. These systems not only suffer from performance inconsistencies and lack of scalability but also fall short in fully embodying the principles of sustainability and circular economy. To address this gap, we propose considering microbial fuel cells (MFCs) as a viable alternative and integral part of the renewable energy ecosystem. MFCs harness the omnipresence, abundance, and cost-effectiveness of their essential components, making them a promising candidate. Through our comprehensive analysis, we shed light on the limitations and advancements of this technology, which underscore the remarkable potential of MFCs to revolutionize our perception of clean, sustainable energy.
İzzet Yüksek, İlker Karadağ
Renewable Energy - Technologies and Applications · 2021
Owing to factors such as high living standards and digitalization, energy use is growing. However, the proportion of renewable energy sources is also rising in all energy consumption. Given this use of renewable energy, global warming and environmental issues are still rising. Fossil-based energy species are more polluting and resource-stricken than others. Studies on environmental pollution show that fossil-based energies are the most important pollutants. Fossil-based energy source is still the most consumed type of energy. Besides, the renewable energy sources’ consumption is very low. Therefore, it is important to increase the use of renewable energy, which creates cleaner and less emissions. Buildings should have the right clean energy use incentives. The needs such as heating, refrigeration, and lighting can be met by renewable energy. This research aims to explore and demonstrate how renewable energy can profit when fulfilling public building functions. Through using both conventional methods and creative methods together, the rate of use of renewable resources such as solar, wind, and geothermal resources in buildings can be increased. Therefore, major contributions to reducing the environmental issues caused by energy consumption can be made.
Nick Jelley
Renewable Energy: A Very Short Introduction · 2020
Abstract ‘Renewable electricity and energy storage’ addresses the transmission of electricity using high voltage alternating or direct current (HVAC or HVDC), the effect of the variability of renewable energy supplies, and the importance of energy storage. Solar and wind farms are now providing an increasing proportion of electricity on many electricity grids. This is changing the requirements on power plants, requiring fast-reacting generators, interconnectors to other grids, demand response, smart grids, and energy storage. There is a cost in accommodating the variability in supply of electricity from wind and solar farms, and surplus supply can lower revenues and give rise to a ‘missing money problem’. Lithium-ion batteries are increasingly important in providing storage for the grid and for electric vehicles. Other storage options are explored, including pumped and compressed air storage, flow batteries, and using electricity to heat or cool water or to generate a combustible fuel (power-to-gas), such as hydrogen, which can be used to provide heat sustainably.
, Preeya Kritthiraput, Kittikorn Sasujit et al.
Engineering and Technology Horizons · 2023
The processing of Black Soldier Fly Larvae (BSFL) for high-quality animal feed protein is being promoted to transformation at the industry level in Thailand. This is due to the fact that the washing process of BSFL generates wastewater with high organic matter that must be treated. This research was interested in studying the potential of methane production from wastewater in the BSFL washing process that is fed by Inca meal and mixed with inoculum sludge from a swine biogas production system at different substrate and inoculum ratio of 3:1, 1:1 and 1:3 by gVS add. The system also controlled the temperature within the mesophilic condition at 35 ± 2°C. The result of this study shows that the optimum ratio which the most biochemical methane potential (BMP) was 1:1 on 45 days of fermentation period. This optimum ratio can also generate the cumulative methane gas production of 401.51 ± 24.42 NmL/gVS add with the highest methane content of 67.90%. The VS removal was 23.76% and the COD removal was 68.51%, which shows the BSFL washing process wastewater can be a substrate for biogas production and further expanded to the industry level.
Xiaofei Zeng, Abhijeet P. Borole, Spyros G. Pavlostathis
RSC Advances · 2016
An MEC bioanode operated under different continuous-flow conditions converts problematic furanic and phenolic compounds to renewable hydrogen.
Nurettin Çek, Aysun Tuna, Ali Çelik et al.
Research Square · 2024
Abstract Plant-based plant microbial fuel cells are introduced as devices that directly convert solar energy into electrical energy through photosynthesis reactions. Plant microbial fuel cells, which are a renewable and sustainable energy source, produce bioelectricity at different levels depending on plant species and characteristics. In this paper, a plant microbial fuel cell was manufactured by planting Aloe vera in natural plant soil and placing graphite electrodes, then it was operated by giving pure water. Thus, an Aloe vera based plant-microbial fuel cell was manufactured and open circuit potential, linear scanning voltammetry and electrochemical impedance spectroscopy tests were performed. The peak open-circuit potential generated by the aloe vera-based plant microbial fuel cell was 288 mV, and the peak value of power density reached levels of 200 W/m 2 . The high activation resistance and ohmic resistance of aloe vera-based plant microbial fuel cell triggered total internal resistance, causing it to show internal resistance at levels of 10 kiloohms. The aloe vera-based system demonstrates promising potential for electricity generation, as evidenced by its peak open-circuit potential. However, the high activation resistance and ohmic resistance leading to a total internal resistance of 10 kiloohms highlight areas for improvement to enhance its efficiency and practicality for widespread use. Further research and development are needed to address these challenges and unlock the full capabilities of aloe vera-based P-MFCs.
Paul F. Meier
The Changing Energy Mix · 2020
In an effort to reduce the amount of crude oil used in the United States, a government program was started in 2002 to examine the use of hydrogen as a transportation fuel. In this application, hydrogen is used in a fuel cell vehicle to produce electricity. This allows a vehicle to enjoy the higher energy efficiency of a battery versus a gasoline-powered vehicle, while avoiding the frequent and long charging times needed for an electric vehicle. There are currently other applications for hydrogen in the United States and the world, primarily in refineries and the manufacture of ammonia. Unlike fossil fuels, such as coal, natural gas, and crude oil, there are no natural sources of hydrogen gas. There are several options for producing hydrogen, such as reforming natural gas or gasifying coal or biomass. Alternatively, a renewable energy source, such as wind or solar, could be used to produce hydrogen via water electrolysis.
Welly Anggraini
Jurnal Pijar Mipa · 2025
This study explores the role of microbial enzymes in the bioconversion of organic waste into renewable energy sources such as bioethanol, biogas, and biohydrogen. Employing a qualitative literature review, this research applies a systematic thematic synthesis to 28 scientific sources, including journal articles, policy reports, and textbooks published between 2018 and 2024. The findings indicate that enzymes such as cellulase, amylase, and lipase play a dominant role in the hydrolysis of organic substrates, breaking down complex biomolecules into glucose, amino acids, and fatty acids. These hydrolysis products are then fermented anaerobically by microbes like Saccharomyces cerevisiae and Clostridium spp. to generate various bioenergy outputs. In addition, the study highlights the importance of biochemical characteristics such as enzyme kinetics, stability, and substrate specificity, which are critical for improving energy conversion efficiency. Operational challenges include high production costs and suboptimal enzyme performance under non-laboratory conditions. However, promising innovations have emerged, including enzyme immobilization techniques, co-fermentation strategies, and the use of genetically engineered microorganisms. Case studies from India, Germany, and Indonesia demonstrate the practical potential of microbial enzyme-based bioconversion systems in transforming agricultural and household waste into valuable energy products. The integration of microbial enzymes into waste management not only reduces environmental pollution but also supports clean energy transition efforts. This research implies the need for policy alignment and educational curriculum integration in environmental science to accelerate public adoption and awareness. This research implies the need for policy alignment and educational curriculum integration in environmental science to accelerate public adoption and awareness.
Paul F. Meier
The Changing Energy Mix · 2020
Geothermal energy is heat taken from below the surface of the earth in the form of either steam or hot water. This energy can be used to generate electricity, but also has use in heating and cooling homes and some direct uses, such as gold mining, food dehydration, and milk pasteurizing. There are four basic types of geothermal power plants including steam, flash, binary, and enhanced geothermal system (EGS). The first three rely on permeable aquifers that have water flowing through them such that hot water or steam can be extracted. EGS, however, extracts heat from deep in the earth by injecting water and creating artificial fractures in the rock. A great deal of the world’s potential for geothermal energy exists in the so-called Ring of Fire, a ring of volcanoes around the Pacific Ocean.
Paul F. Meier
The Changing Energy Mix · 2020
Just as a fossil fuel can be burned to generate steam and drive a turbine, biomass can also be burned as a fuel to generate electricity. Biomass comes in many forms, such as wood and wood waste, agricultural waste, municipal waste, and energy crops. In the United States, biomass accounted for 1.5% of electricity generation, and was about 9% of electricity from renewables. Two-thirds of electricity from biomass comes from wood and wood waste. An advantage of using biomass as a fuel is that plants remove carbon dioxide (CO 2 ) from the atmosphere through photosynthesis, thereby recycling the CO 2 made from combustion. The overall footprint of a biomass-to-electricity plant is dominated by the land area needed to grow and harvest the biomass fuel.
Paul F. Meier
The Changing Energy Mix · 2020
A wind farm is a collection of wind turbines, sufficiently spaced to avoid wind interference between turbines. Onshore and offshore are the two basic types of wind farms. The cost of building an offshore farm is greater because of the need for turbines that withstand high wind and corrosive conditions of the sea, plus the expense of installing underwater transmission cables to shore. For an onshore wind farm, the land area for the farm is large, but the direct impact area is relatively small. The direct impact area includes the turbine pads, roads, substations, and transmission equipment, and only makes up about 2% of the total wind farm area. Since the direct impact area is small compared to the total wind farm area, agriculture and ranching can coexist with the wind farm. Wind is a very fast growing renewable energy technology. In the ten years since 2009, the worldwide capacity for wind power increased 276% while US capacity increased 175%.
Paul F. Meier
The Changing Energy Mix · 2020
There are two basic approaches for using solar energy to generate electricity. The first type, solar photovoltaic (PV) energy, uses semiconductors to convert sunlight into electricity. Crystalline silicon semiconductors are the most common type in use. The second approach is called concentrating solar power (CSP), also referred to as solar thermal. Basically, CSP uses mirrors to concentrate sunlight and generate steam, which is used to power a turbine. The most common method employed commercially is the parabolic trough, where the mirrors are horizontally disposed in a parabolic shape. Solar PV is more commonly used commercially because of high capital costs for building a CSP power plant. Solar PV has experienced rapid growth over the last ten years, increasing by more than twentyfold in the United States. Growth for CSP has increased threefold over the same ten years, but no growth over the last four years. Spain and the United States lead the world in commercial CSP plants.
Paul F. Meier
The Changing Energy Mix · 2020
There are two methods for generating electricity from hydropower. The first, and by far the most common, is the use of flowing water to rotate a turbine, which then turns the generator shaft to generate electricity. For this type of “conventional” hydroelectric, there are two general approaches. The first is a storage dam, where water impoundment upstream of the dam is used to make a reservoir to store water, thus creating a vertical drop in water elevation and giving control over water flow. The second is a run-of-river scheme, such that a portion of a flowing river is diverted to generate electricity. The second method for generating electricity is called pumped storage. In this scheme, water is pumped from a lower to upper reservoir in order to store energy in the form of gravitational potential energy to be used later. In this respect, the system is operating as a battery to store energy for future use. The states of Washington, California, and Oregon control about half of the total US capacity.
Ganjar Samudro
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan · 2016
Penggunaan energi yang besar meningkatkan emisi CO2 yang terlepas ke atmosfer. Upaya konservasi energi terus dilakukan dalam rangka meningkatkan kebutuhan energi. Bentuk konservasi energi berbasis renewable energy technology dengan pemanfaatan teknologi microbial merupakan bentuk ideal back to nature dan lebih ramah lingkungan untuk masa depan lingkungan yang lebih baik. Penelitian-penelitian berbasis teknologi microbial dengan basis modifikasi teknologi konvensional dengan advanced menjadi pilihan terbaik dalam capture energi besar, kebutuhan energi nol, revenue listrik tinggi dan biaya operasional yang rendah. Pilihan inovasi teknologi ini membuka wacana pengembangan inovasi teknologi microbial lainnya dan memberikan kontribusi pengurangan emisi CO2 dari suatu proses. Hasilhasil penelitian terbaru dengan reaktor MFCs sebagai salah satu teknologi microbial didapatkan kecenderungan positif dalampemanfaatannya dalam skala yang lebih besar dan aplikatif.
Seyul Son, N. C. Goulbourne
ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, Volume 1 · 2010
In this paper, constitutive equations to model the electromechanical behavior of shape memory polymers (SMPs) are introduced for the first time. SMPs are unique material that can be transformed into complicated shapes and recover their original shapes even under large deformations [1]. Above their transition temperature, elastic modulus decreases and they can be easily deformed by mechanical or electrical input. Advantage of this behavior is returning to the deformed shape utilizing a triggering temperature without any applied forces. This can be used to actuate the electroactive polymer to restore the deformed shape without applying an electric field [2]. Therefore in this paper, the equibiaxial extension of two different SMPs (PTBA (poly(tert-butylacrylate)) [2] and Sylgard (Sylgard 184)/PCL (poly(ε-caprolactone)) composite [3]) is simulated numerically to demonstrate the electromechanical behavior with respect to mechanical and electromechanical inputs. For simplification, the response of the SMP above the transition temperature is considered, so that material properties are constant and not a function of temperature. The SMPs are considered a fiber-reinforced membrane with two families of fibers, which enable to tune the material properties of SMPs [3]. To describe the constitutive relation of the SMPs, Mooney-Rivlin and Ogden model for isotropic SMPs, as well as Gasser et al model [4] for anisotropic SMPs, are applied. In the numerical computations, the isotropic and anisotropic electromechanical response of PTBA and Sylgard/PCL composite are presented. PTBA shows larger electromechanical effect in the range of stretch 1.5–2.5. Additionally, the effects of the fiber stiffness, angle, and dispersion on the deformation of the SMPs are observed. According to the result, the fiber stiffness can significantly affect on the electromechanical response and fiber angle and dispersion can influence the anisotropic deformation.
Jingwen Wang, Hani E. Naguib, Aimy Bazylak
ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 2 · 2010
In this work, electroactive polymers (EAPs) are introduced as novel materials for the polymer electrolyte membrane fuel cell (PEMFC). Polypyrrole (PPy) is selected as a promising EAP for the PEMFC. The fabrication procedures including the polymer solution preparation and the electro-chemical deposition process for producing a thin and porous PPy film are presented. The activation behavior of PPy thin film is observed, and the surface properties are analyzed.
Cláudia A. Silva, Joana Moreira, Marta Fernandes et al.
Polymers · 2025
Indwelling medical devices, such as urinary catheters, often experience bacterial colonization, forming biofilms that resist antibiotics and the host’s immune defenses through quorum sensing (QS), a chemical communication system. This study explores the development of antimicrobial coatings by immobilizing acylase, a quorum-quenching enzyme, on sandblasted polydimethylsiloxane (PDMS) surfaces. PDMS, commonly used in medical devices, was sandblasted to increase its surface roughness, enhancing acylase attachment. FTIR analysis confirmed that acylase retained its three-dimensional structure upon immobilization, preserving its enzymatic activity. The antibacterial efficacy of the coatings was tested against Pseudomonas aeruginosa (P. aeruginosa) (a common biofilm-forming pathogen), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The results showed that sandblasted PDMS surfaces had improved bacterial adhesion due to increased focal adhesion points, but acylase-functionalized surfaces had significantly reduced bacterial attachment and biofilm formation. Notably, the coatings inhibited P. aeruginosa growth by 40% under static conditions, demonstrating the potential of acylase-functionalized PDMS for medical applications. This approach offers a promising strategy for creating antimicrobial surfaces that prevent biofilm-related infections in urinary catheters and other medical devices. The findings highlight the dual role of surface roughness in enhancing enzyme attachment while reducing bacterial adhesion through effective QS inhibition.
Lucinda Elizabeth Doyle, Pui Yi Yung, Stefan Wuertz et al.
ECS Meeting Abstracts · 2015
Electrochemically-active microorganisms couple the degradation of organic matter to the production of electricity via extracellular electron transfer. They are usually enriched from sediments via growth at certain potentials, either in microbial fuel cells or in potentiostat-controlled electrochemical cells. Despite the great microbial diversity of sediments from natural and man-made environments, most electrochemical enrichments select a small group of dissimilatory metal-reducing microorganisms. In this study, we aim to enrich novel electrochemically-active strains in sediments from various equatorial environments. Sediment inocula from urban waterways and mangroves were tested in long-term enrichment experiments at controlled anodic potentials. In addition to the conventional voltamperometric characterisation, the biofilm formed at the working electrode was subjected to electrochemical impedance spectroscopy (EIS) over a wide range of potentials. EIS of the biofilms revealed several charge transfer routes at different potentials and with different characteristic times. Furthermore, EIS enabled monitoring of the long-term changes of the electroactive biofilm and quantification of the effect of biofilm accumulation on the conductivity of the biofilm/electrode interface. Electrochemical analysis was coupled to metagenomics and metatranscriptomics to reveal novel electrochemically-active microorganisms and to understand their charge-transfer mechanism. The understanding of the microbe/electrode interaction in the sediments will assist in controlling the dynamic of metal cycling in urban sediments. Furthermore, novel electrochemically-active microorganisms will find application in bioremediation and environmental sensing applications.
William M. Aguilera, Mary I. Frecker, Randy Haluck
Volume 2A: 27th Design Automation Conference · 2001
Abstract A model has been developed to design a new active, steerable end-effector for minimally invasive surgery. Active material is incorporated into the surgical instrument to increase the degrees of freedom available to the surgeon. This paper focuses on the modeling of the end-effector using both piezoelectric ceramic and electroactive polymer (EAP) materials. The end-effector design consists of a number of bimorph actuator sections in series with each active layer being individually controlled. Each section may behave as either a bimorph or a unimorph actuator, where in the case of unimorph one of the active layers is passive. By varying the strength and direction of the electric field across each section, a prescribed overall shape can be achieved to allow the user to steer the device. The piezoceramic device is modeled using strain energy methods to predict the quasi-static force-deflection behavior. In the EAP model, experimental data for the electrostrictive P(VDF-TrFE) copolymer is used to model the non-linear relationship between the electric field and the induced strain. Due to the large deflections achievable with the EAP, a model for large deflections beams is also used. Modeling is carried out using MATLAB and then the behavior of piezoelectric ceramic is compared to that of electro-active polymer (EAP).
Lucinda Doyle, Stefan Wuertz, Enrico Marsili
ECS Meeting Abstracts · 2014
Sediments are usually enriched in electrochemically active microorganism via growth at defined potential, either in Microbial Fuel Cells or in potentiostat-controlled electrochemical cells. Despite the great microbial diversity of sediments from natural and man-made environment, most electrochemical enrichments select a small group of dissimilatory metal-reducing microorganisms. In this study, we aim to enrich novel electrochemically active strains in sediments from various equatorial environments. Sediment inocula from urban waterways, industrial area, and mines were tested in long-term enrichment experiments at controlled anodic potentials. In addition to the conventional voltamperometric characterization, the biofilm, formed at the working electrode was subjected to Electrochemical Impedance Spectroscopy (EIS) over a wide range of potentials. EIS of the biofilms reveal several charge transfer routes at different potentials and with different characteristic times. Furthermore, EIS enable monitoring the long-term changes of the electroactive biofilm and quantifying the effect of biofilm accumulation on the conductivity of the biofilm/electrode interface. Electrochemical analysis is coupled with meta-genomic and meta-transcriptomics to reveal novel electrochemically active microorganisms and to understand their charge transfer mechanism. The understanding of the microbe/electrode interaction in the sediments will help controlling the dynamic of metal cycling in urban sediments. Furthermore, novel electrochemically active microorganism will find application in bioremediation and environmental sensing applications.
James A. Behan, Ricardo O. Louro, Frédéric Barrière
Encyclopedia of Inorganic and Bioinorganic Chemistry · 2023
Abstract This article gives an up‐to‐date (2023) account on the bioinorganic basis for extracellular electron transfer (EET) in electroactive bacteria. These microorganisms connect their respiratory metabolism to extracellular solid electron acceptors or donors, typically metal oxides of iron or manganese. Thanks to this peculiar property, electroactive bacteria can develop as biofilms at electrodes, be studied electrochemically, and form the basis of diverse potential applications termed microbial electrochemical systems (MES). The metalloproteins forming the respiratory chain from NADH oxidation to the reduction of the terminal solid electron acceptor are described in detail for the most studied Gram‐negative electroactive strains developed at anodes: Shewanella oneidensis MR‐1 and Geobacter sulfurreducens . Although less efficient than their Gram‐negative counterpart and sometimes referred to as weak electricigens, an example of electroactive anodophile Gram‐positive bacteria, Thermincola sp., is also discussed. The key cytochromes involved in the electron transport chain are discussed such as outer membrane c ‐type cytochromes (Omc) and multiheme cytochromes, forming by self‐assembly up to micrometer‐long electron conductive extracellular pili or nanowires. The case of microorganisms that uptake electrons from solid extracellular electron donors is addressed with a highlight on photoferrotrophs and cathodic denitrifying bacteria. Finally, the common strategy developed by different bacteria to electrically connect different types of respiratory metabolism is stressed together with the apparent ubiquity of EET across life domains including archaea.
Hanna Frühauf, Markus Stöckl, Dirk Holtmann
· 2020
<p>Mechanisms of electron transfer vary greatly within the diverse group of electroactive microorganisms and so does the need to attach to the electrode surface, e.g. by forming a biofilm.</p> <p>Electrochemical impedance spectroscopy (EIS) and confocal laser scanning microscopy (CLSM) are well established methods to monitor cell attachment to an electrode surface and have therefore been combined in a flow cell as a screening system. The flow cell, equipped with a transparent indium tin oxide working electrode (ITO WE), allows monitoring of attachment processes in real time with minimal needs for additional biofilm preparation. In preliminary experiments the flow cell was successfully used as microbial fuel cell (MFC) with a potential of +0.4 V vs. Ag/AgCl using <em>Shewanella oneidensis</em> as electroactive model organism. [1]</p> <p>Commonly, graphite-based electrode materials are used in bioelectrochemical systems due to their low costs and high conductivity. However, the hydrophobic and negatively charged surface is not yet optimal for microbial attachment. There are numerous attempts on electrode surface engineering in order to overcome this problem. In the majority of studies the biofilm analysis and evaluation of the attachment takes place at the end of the experiment, neglecting the impacts of the chemical surface properties and initial electrode conditioning during the very beginning of biofilm formation.</p> <p>To investigate initial attachment and biofilm formation in real-time, the transparent ITO-electrode is coated with polyelectrolytes differing in hydrophobicity and polarity to evaluate their effects on the initial surface colonisation by different electroactive microorganisms. Combining CLSM and EIS, both, surface coverage and electrochemical interaction of electrode-associated bacteria can be assessed.</p> <p>With this we aim to understand and ease initial steps of biofilm formation to improve efficiency of bioelectrochemical applications, e.g. with regards to start-up time.</p> <p> </p> <p>[1] Stöckl, M., Schlegel, C., Sydow, A., Holtmann, D., Ulber, R., & Mangold, K. M. (2016). Membrane separated flow cell for parallelized electrochemical impedance spectroscopy and confocal laser scanning microscopy to characterize electro-active microorganisms. <em>Electrochimica Acta</em>, 220, 444-452.</p>
Maria Irene Lopez-Cazares, Jessica Viridiana Garcia-Meza, Erika Roxana Larios Duràn et al.
ECS Meeting Abstracts · 2015
The chalcopyrite is a sulfide mineral (SM), that is the main copper source, which is extracted by oxidative leaching. As initial reaction products, secondary phases of sulfur, such as S n 2- and S 0 are formed [1], which are sulfur chains and sulfur rings [2], respectively. These phases tend to deposited on chalcopyrite surface, limiting ion and electron transferences between mineral and solution, so the reaction kinetic results decresed [1] . One of the options suggested to avoid this condition, is to remove sulfur phases by biooxidation with Acidithiobacillus microorganisms, such as Acidithiobacillus thiooxidans (sulfurooxidizing microorganism SOM) and Leptospirillum sp. (ironoxidizing microorganisms, IOM) [3,4]. It has been found that direct contact mechanisms of chalcopyrite bioleaching occurs by attachment of microorganisms, which is improved by the initial presence of sulfur phases, mainly for Acidithiobacillus thiooxidans . In addition, a different behavior has been observed as a function of kind of sulfur phase, which influences on the physicochemical and biological characteristics of the biofilm developed during the biooxidation [5,6]. Hence, for SOM the hydrophobic composition of EPS (extracellullar polymeric substances) and cell density of the biolm is improved by presence of S 0 on mineral surface, affecting the biooxidation process of chalcopyrite. However, the above has been only evaluated for SOM systems, hence, that would be important analyze the effect of sulfur phases on the performance of IOM systems, due to it will keep the presence of an oxidant agent (ferric iron), which will affect improves the electrochemical process, such as would occur in the SOM+IOM consortia used in the industrial bioleaching process. So, in this work the objective is analyze the electrochemical process of system bacteria - electrolyte – mineral on modified chalcopyrite surface exhibting different sulfur species exposed to SOM and SOM+IOM cultures. For this the chemical changes in electrolyte, and morphological, composition and hydrophobic modifications on surface exposed to microorganisms are correlated with Electrochemical impedance Electrochemical (EIS) and Electrochemical Noise (EN) data obtained for each evaluated condition. Global analysis of the results shows that the presence of microorganisms improves the ionic and electronic activity of interface, due to the initial sulfur phases (S n 2- and S 0 ) generated by potentiostic oxidation were removed. Then, a secuencial and cyclic transformation between several kinds of reactive sulfur species, determined the electroactivity and hydrophobicity of chalcopyrite surface as a function of bioleaching time, which influences the oxidation capacity of microorganisms. In addition, it was found that on S n 2- rich surfaces, oxidation was improved with SOM, by an uniform mechanism of acidic dissolution and through indirect contact, these associated with SOM membrane enzymatic characteristics, according to [2,7]. However, on S 0 rich surfaces, the bacterial activity occurred by direct contact, but was slower than on S n 2- , due to generation of hydrophobic and inactive (passive) sulfur species. Such kind of phases were result of a low amount of EPS-Fe 3+ complexes that limited the ring sulfur activation, based in the reported in [2], and therefore the charge transfer and diffusion processes. On the other hand, SOM+IOM showed higher activity by an uniform mechanism of ferric dissolution on both sulfur phases, but it was mainly by direct contact on initial S 0 surface, generating predominantly hydrophilic and reactive surfaces species at early times, which was associated to higher amount of EPS-Fe 3+ , that contributed with either fast activation of initial ring S 0 [2] and mass transfer. References: [1] Klauber C, Int J Miner Process, 86:1-17 (2008). [2] Meyer B, Chem Rev , 64 (4):429-451 (1964). [3] Pan HD, Yang HY, Tong LL, Zhong CB, Zhao YS Trans Nonferrous Met Soc China 22:2255−226 (2012) [4] Anjum F, Shahid M, Akcil A, Hydrometallurgy 1-12:117-118 (2012). [5] González D, Lara R, Valdez-Pérez D, Alvarado K, Navarro-Contreras H, Cruz R, García-Meza JV Appl Microbiol Biotechnol 93:763–775 (2012). [6] Lara R, García-Meza JV, González I, Cruz R, Appl Microbiol Technol 95, 799 (2012). [7] Franz B, Lichtenberg H, Hormes J, Modrow H, Dahl V, Prange A, Microbiol 153:1268-1274 (2007).
Arnulfo Rojas-Pérez, Delmaliz Barreto-Vázquez, Santosh H. Vijapur et al.
ECS Meeting Abstracts · 2019
The recycling of human urine has become a main research area in wastewater treatment due to the increased demand for water. Urine is composed of 95% water, 2% urea and other organic and inorganic compounds. Urea is a toxic molecule that may cause renal failure and gastrointestinal bleeding. Nevertheless, it is difficult to remove by common methods since it is a small, uncharged molecule. In this work, the use of Proteus vulgaris is proposed, a bacterium that contains urease, to catalyze the urea conversion to ammonia. The latter can then be oxidized by a platinum electrode while producing a current leaving a urea-ammonia-free solution. This system was first tested in synthetic human urine (SHU) simulating the ureolytic bacterium behavior. The ammonia oxidation current (AOC) was evaluated by cyclic voltammetry (CV) using Pt electrode in SHU, obtaining better results when less urea was present in solution. Preliminary, AOC was evaluated while the bacterial grew in Enriched Synthetic Human Urine (SHU + growth factors). The experiment was carried out for 24 hours showing not only bacterial viability and actual growth in the medium but an increased AOC over time.
Konatsu Ichikawa, Taiki Adachi, Keisei Sowa et al.
ECS Meeting Abstracts · 2024
Bioelectrocatalysis is a coupled system with enzymatic and electrode reactions. Some oxidoreductases can directly communicate with electrodes, which is called direct electron transfer (direct ET; DET)-type bioelectrocatalysis. The number of enzymes proceeding with DET-type reactions is still limited, and its mechanism is not fully elucidated. However, it is expected to be applied to electrochemical devices such as biosensors, biofuel cells, and bioreactors, owing to energy efficiency, biocompatibility, and design flexibility. In addition, this reaction is utilized for enzyme characterization based on kinetics and thermodynamics. In particular, a relationship between DET activity and the redox potential can be quickly and precisely characterized. We focused on aldehyde dehydrogenase (ALDH) from Gluconobacter oxydans , a membrane-bound protein catalyzing DET-type acetaldehyde oxidation. In previous studies, the three-dimensional structure of ALDH was elucidated using cryo-electron microscopy analysis (PDB: 8GY3). The structure is composed of the catalytic large subunit (L subunit), the small subunit (S subunit), and the cytochrome c subunit (C subunit). In vivo , electrons extracted from acetaldehyde are transferred to ubiquinone via the catalytic center (molybdenum cofactor; Moco) in the L subunit, two iron-sulfur clusters (FeSs) in the S subunit, and three hemes c in the C subunit, in this order. The ET associated with substrate oxidation through the C subunit is conserved in membrane-bound hemoproteins such as alcohol dehydrogenase, fructose dehydrogenase, and glucose dehydrogenase. These enzymes have similarities in high DET activities, and their variants truncating a C subunit, which are advantageous in ignoring interference of detergents and complexity of the multi-step ET through hemes c , have been characterized. However, such research has not been conducted for ALDH, and ALDH has the unique feature of having two cofactors in the S subunit. In this study, we attempted to quantitatively characterize the ALDH variant deleting the C subunit (ΔC_ALDH), focusing on pH dependence of kinetic and thermodynamic parameters. To construct an expression system of ΔC_ALDH, a plasmid containing genes of L and S subunits of ALDH was transformed into the knock-out strain in which genes of wild-type ALDH were disrupted. ΔC_ALDH was expressed in soluble fraction as expected and successfully purified. Cyclic voltammograms were recorded at ΔC_ALDH-modified multi-walled carbon nanotube-electrodes. The electrode showed clear DET activity, suggesting that the electrode-active site seems to be FeS which is located near the surface of the enzyme. In addition, we investigated the pH dependence of the DET activity and kinetically analyzed the voltammograms using a model in which distribution of enzyme orientation was considered. The kinetic analysis quantitatively estimated the formal potential of the electrode-active site ( E °′ E ), the limiting catalytic current density ( j cat ), and the ratio of the maximum value of the standard rate constant of the heterogeneous ET to the catalytic constant in DET-type reaction ( k ° max / k c,DET ). j cat exponentially increased from pH 2.5 to 5.5 and reached a plateau between pH 6.0 and 8.0, while E °′ E changed by –48 mV pH –1 from pH 2.5 to 5.5 and became constant between pH 6.0 and 8.0. Since the formal potential of acetate/acetaldehyde redox couple ( E °′ S ) changes by –89 mV pH –1 , E °′ E – E °′ S increases as the condition becomes more basic. Then, we focused on a relationship between the potential difference and DET activity. The log ( j cat / mA cm –2 ) vs. E °′ E – E °′ S plot showed a linear increasing region and a constant region independent of E °′ E – E °′ S , as shown in Figure 1. The former slope suggested that DET activity obeyed the ideal linear free energy relationship (LFER) without any specific interaction. In this region, k c,DET was controlled by the potential difference in the ET pathway. When E °′ E – E °′ S is sufficiently large, k c,DET seems to be limited by other factors such as entry of substrate into the catalytic site, a catalytic turnover in Moco, and the intramolecular ET. On the other hand, in the assay with ferricyanide as an alternative electron acceptor, the slope representing the ideal LFER was not observed. We assume that the potential difference between the enzyme and ferricyanide was insufficient, thus the catalytic constant in solution ( k c,solution ) was kinetically analyzed based on the ping-pong bi-bi mechanism considering changes in E °′ E , E °′ S , and the formal potential of ferricyanide/ferrocyanide. Using parameters obtained from the analysis for j cat and k c,solution , Γ E,eff , k ° max , and k c,DET were separately evaluated with an assumption that Γ E,eff was independent of pH. In summary, we quantitively characterized the bioelectrochemical parameters of ΔC_ALDH and compared the properties between DET and ferricyanide reductase activities. This work will be beneficial for understanding ALDH, and comparing it with wild-type ALDH will elucidate the roles of the C subunit. Figure 1
Andrea Schievano, Laura Rago, Andrea Goglio et al.
ECS Meeting Abstracts · 2019
The industrial synthesis (Haber-Bosch process) of mineral-N has been showing its dark side. Facing the enormous challenge of feeding humankind new technological solutions should enable sustainable nitrogen (N) fixation, to preserve soil fertility. We introduce a new type of microbial electrosynthesis, aimed at simultaneously fixing N 2 and inorganic carbon. In this new perspective, the aim is enhancing biological nitrogen fixation by electrostimulation of complex microbial communities, to produce whole biomass, which can be used as soil fertilizer. Two preliminary contributions in this field reported: a) a bioelectrochemical version of the Haber-bosh process, where methyl viologen shuttled electrons to purified nitrogenase enzymes (Milton et al., 2017) and b) the stimulation of N-fixation in a pure planktonic culture of X. autotrophicus by H 2 -evolution with a specific abiotic catalyst (Liu et al., 2017). Here, a cathodic biofilm was enriched in electro-active autotrophic nitrogen fixers, starting from a mixed microbial culture. The cathode, a carbon-fibers conductor, was kept under constant polarization (-0.7 V vs SHE). Biomass (in the biofilm, as well as in the bulk liquid phase) was synthesized at significantly higher rates (up to 18-fold), as compared to controls kept at open circuit (OC). Along over 100 days, electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated to autotrophs (both Archaea and Bacteria ) only in polarized biofilms, while not in OC control. Genes copies encoding for a series of known proteins associated to extracellular electron transfer were double in polarized trials, as compared to controls. The first results of such an approach were recently published in Bioelectrochemistry (Rago et al., 2019). From this proof-of-the-concept, we propose to call this promising field ‘bio-electrochemical nitrogen fixation (e-BNF)’, that deserve future research efforts in both fundamentals and applicative aspects. Liu, C., Sakimoto, K.K., Colón, B.C., Silver, P.A., Nocera, D.G., 2017. Ambient nitrogen reduction cycle using a hybrid inorganic–biological system. Proc. Natl. Acad. Sci. 114, 6450–6455. doi:10.1073/pnas.1706371114 Milton, R.D., Cai, R., Abdellaoui, S., Leech, D., De Lacey, A.L., Pita, M., Minteer, S.D., 2017. Bioelectrochemical Haber–Bosch Process: An Ammonia-Producing H2/N2Fuel Cell. Angew. Chemie - Int. Ed. 56, 2680–2683. doi:10.1002/anie.201612500 Rago, L., Zecchin, S., Villa, F., Goglio, A., Corsini, A., Cavalca, L. & Schievano, A. 2019, ‘Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation’, Bioelectrochemistry, vol. 125, pp. 105–15. Figure 1
Federica Arena, Giorgio Giuffredi, Andrea Perego et al.
ECS Meeting Abstracts · 2019
The ever-increasing worldwide energy demand and anthropogenic emissions produced by the combustion of fossil fuels, along with the consequent increment in the global average temperature, have pushed the scientific community towards the development of energy vectors with minimal carbon footprint. Electrochemical -reduction is an approach that holds potential for exploiting the cyclic reduction and oxidation of carbon-based fuels. As of today, high efficiency in these systems can only be achieved by employing precious metals, which suffer from both low natural availability and high costs as well as unsatisfactory energy efficiencies and lack of conversion product specificity. Recently, the development of a novel hybrid technology based on the combined use of biological organisms or molecules and nanomaterials has created great opportunities to produce renewable fuels and chemicals from the reduction of with a minimal overpotential. According to this, the enzymatic electrosynthesis (EES) exploits pure enzymes to catalyze reactions with higher transformation efficiency, higher activity under controlled experimental conditions and higher selectivity towards both specific substrates and products. The first step of CO 2 reduction enzymatic process consists of the production of formic acid using the catalytic properties of the enzyme formate dehydrogenase (FDH) (EC 1.2.1.2.). Unlike most metallic catalysts, this enzyme reversibly catalyzes the transformation of CO 2 to formate as the only product of the reaction. In this contest, we used the NAD-dependent FDH from the aerobic bacterium Thiobacillus sp. KNK65MA ( Ts FDH) for its superior -reducing activity (K cat = 0.318 s -1 )[1]. Surface chemistry and surface morphology play a key role in the interaction between the enzyme and the electrode, ultimately affecting the successful development of a bioelectrochemical system (BES). In fact, the atomic composition of the material and its structure affect enzyme immobilization, which in turn influences the electrochemical performance of the EES. In this context, titanium nitride (TiN) can be efficiently used as a scaffold for enzyme immobilization by exploiting its surface-exposed Ti 4+ atoms for the binding. As such, TiN has been described as a promising general catalyst support material. Indeed, TiN features high electrical conductivity, good biocompatibility, as well as outstanding oxidation and acid corrosion resistance, together with a hybrid metallic/ceramic behaviour[2]. The aim of this work is to realize a nanostructured TiN scaffold featuring an increased available surface area to enhance the interface between the enzyme and the electrode. To this end, we developed a novel hybrid device where the FDH enzyme from Thiobacillus sp. KNK65MA (EC 1.2.1.2) is deposited on a nanostructured mesoporous support of TiN fabricated by Pulsed Laser Deposition (Fig.1a). This deposition method allows the production of a biocompatible nanostructured support with high surface area and a tree-like morphology. Its high porosity and high specific area maximize the contact with the enzyme, thus improving the efficiency of the EES for reduction. In order to identify the most suitable film morphology, the immobilization process on TiN support with different porosity was assessed by enzymatic assay after drop-casting (active area of 1 cm 2 ). The results show that there is an increase in the amount of Ts FDH that is bound to the TiN nanostructure when the porosity, and therefore the surface area, of the nanostructure increases. For the more porous morphology the percentage of adsorbed Ts FDH is 48%, corresponding to 1 µg of specifically-adsorbed Ts FDH. After, a calibration curve was performed to determine the maximum binding capacity of the TiN support. The result shows that, by increasing the concentration of the drop-casted Ts FDH, the enzyme unit calculated on the surface increases until a Ts FDH loading quantity of 1,14 mg is used, corresponding to 59 µg of immobilized protein. To assess the CO 2 reduction electrochemical performance of the TiN| Ts FDH electrode, chronoamperometric measurements were done at a constant potential of -0.45V RHE . The TiN support alone shows a stable reduction current (-130 µA ), due to hydrogen evolution (HER) occurring on the surface of the electrode (blue line, Figure 1b). Then, we tested the CO 2 reduction activity of the enzyme-conjugated electrode (green trace, Figure 1b). A reductive current density with higher magnitude of -190 µA was registered, showing the actual operation of the BES system. After test, the solution was examined by 1 H NMR spectroscopy. The peak signal at 8.455 ppm in NMR spectra demonstrates that the formic acid is the only product of the catalytic reaction performed by Ts FDH. This result was used to quantify the amount of formic acid synthetized in the BES. During a 3 h reaction period, the electrosynthesis of formic acid was about 5.3±0.4 μmol under potential applied of -0.45V RHE . [1]H.Choe; PLOS ONE (2014). [2]P.H.; Electrochimica Acta( 2010) Figure 1
Taiki Adachi, Kenji Kano, Keisei Sowa et al.
ECS Meeting Abstracts · 2024
In vivo, a variety of enzymatic cascade reactions are working to efficiently and rapidly metabolize biomolecules. Oxidoreductases especially play key roles in biochemical redox reactions such as fermentation, respiration, and photosynthesis, which might lead to efficient conversion of eco-friendly materials and production of useful compounds. Some enzymatic redox reactions can be artificially coupled with electrode reactions, which is called bioelectrocatalysis. Particularly, an electrical communication without any external electron mediators is called direct electron transfer (DET)-type bioelectrocatalysis, which can be an analytical system evaluating kinetic and thermodynamic characteristics of enzymes, and are expected to be applied to biomimetic devices such as biofuel cells, bioreactors, and biosensors. We focused on two DET-type enzymes: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) from acetic acid bacteria ( Gluconobacter oxydans ). Both enzymes form heterotrimeric structures composed of the catalytic large subunit, the chaperonic small subunit, and the membrane-bound cytochrome c subunit. They physiologically play key roles in the respiration, and the electrons are transferred from substrates to ubiquinone in the periplasmic space. Although DET activities of ADH and ALDH have been already reported, their three-dimensional (3D) structures remain unknown, which prevents the elucidation of detailed electron transfer pathways and improved DET-type bioelectrocatalysis of ADH and ALDH. In this study, we attempted to establish the bienzymatic cascade for bioelectrochemical 4-electron oxidation of ethanol into acetate via acetaldehyde, using ADH and ALDH. To optimize the surface structure of electrodes for the two enzymes by considering their structural characteristics, we firstly elucidated the 3D structures of ADH and ALDH using cryo-electron microscopy analysis. The 3D structures were reconstructed with a 2.5 Å resolution for ADH and a 2.7 Å resolution for ALDH, respectively. Pyrroloquinoline quinone and four hemes c were resolved in ADH, while a molybdenum cofactor, two iron-sulfur clusters, and three hemes c were resolved in ALDH. Cyclic voltammograms were then recorded at multi-walled carbon nanotube-modified glassy carbon electrodes (CNT/GCs) functionalized with five pyrene derivatives and the enzyme (ADH or ALDH). Regardless of pyrene modification, all prepared electrodes performed clear DET-type ethanol oxidation by ADH and acetaldehyde oxidation by ALDH, respectively, and the 1-pyrenecarboxylic acid (PyCOOH)-functionalized CNT/GC showed the best catalytic properties for both ADH and ALDH. Based on the electrochemical results, PyCOOH-functionalized CNT/GC was selected as an electrode platform for bienzymatic electrochemical cascade. The electrodes were functionalized with a mixture of ADH and ALDH. The molar concentrations of ADH and ALDH ( c 1 and c 2 , respectively) were variously controlled under the condition that c 1 + c 2 was constant. The apparent DET-type current density for ethanol oxidation reached a maximum around log ( c 1 / c 2 ) = 0.5, which was higher than that at c 1 / c 2 = ∞ (only ADH). Such increase in the DET-type current density indicates that acetaldehyde produced by ADH was subsequently oxidized by ALDH, which means a bienzymatic cascade. A mathematical model for a bienzymatic DET-type cascade reaction was constructed using the experimental results. These calculations indicated that the ratio of the amounts and catalytic constants of the two enzymes was a key factor controlling the performance of the bienzymatic cascade. In addition, the nanostructure of the enzyme-electrode interface which seems to affect diffusion of the intermediate product was also important for improving cascade efficiency. An ethanol/air biofuel cell was finally constructed with a bienzyme (ADH and ALDH)-functionalized bioanode and a bilirubin oxidase (BOD)-functionalized biocathode. The open-circuit voltage, the maximum current density, and the maximum power density were 0.75 ± 0.02 V, 2.69 ± 0.09 mA cm –2 , and 0.48 ± 0.01 mW cm –2 , respectively. Comparing these characteristics with those of a biofuel cell without ALDH, the performances were improved by ALDH co-adsorption. The ethanol/air biofuel cell worked much better than any other ethanol biofuel cells reported to date. The Faraday efficiency for acetate production of the ethanol/air biofuel cell reached 100 ± 4%, which indicates that the bienzymatic DET-type cascade using ADH and ALDH performed highly efficient 4-electron oxidation of ethanol into acetate. A conceptual diagram of the system is shown in the attached figure. These works will enhance the utilization of biomass fuels and lead to a low-carbon society. These discussions also suggest that the design of the nanostructured interface between the catalysts and electrodes are important for efficient turnover of the intermediate product in the multi-catalytic cascade system. Figure 1
Li Wang, Yang Sun, Ning Hu et al.
ECS Meeting Abstracts · 2016
The Bio-electrochemical catalysis reactor (BECR) is employed to purify SOx, NOx, carbon dioxide and other pollutants from mineral processing flue gases in mineral processing. They are converted into sulphur and nitrogen and high added-value biofuels via biological agent of seperating air/pollutants and bioelectrocatalysis reversal process (BECRP). Biofuel producing bacteria and BECR reactors are coupled to a system, and the BECRP is utilized and realized to purify mineral processing flue gas and convert carbon dioxide biofuel in the reactors. The metabolic products, mineral processing flue gas components of influx and exhaust and other processing parameters are analysed by using online Micro-GC, HPLC-MS, and etc. The influences of microbial metabolic pathway of the BECRP and low voltage loading on the bacteria and the electrode reaction mechanism in the electrode process are investigated. The multi-variable bioelectrochemical transition matrix and optimal parameters are established to improve the flue gas purification efficiency and the conversion rate of carbon dioxide.
E. Lavrentyeva, T. Banzaraktsaeva, V. Dambaev et al.
IOP Conference Series: Earth and Environmental Science · 2021
We studied the taxonomic diversity of microbial mat in the Uro hot spring (the Baikal rift zone, BRZ) with temperatures of 62°C (Ur-3) and 56°C (Ur-4). According to the results of high-throughput sequencing, the composition of the community is represented by various phylogenetic groups Cyanobacteria, Proteobacteria, Deinococcus-Thermus, Chloroflexi, Firmicutes, and Bacteroidetes involved in different stages of organic matter production and degradation in microbial mats. According to metagenomic analysis, there is a wide variety of natural peptidases, enhancing the potential of their specialised functions of energy and substance conversion in microbial mats.
Laurentia Artiomov
5th International Scientific Conference on Microbial Biotechnology · 2022
The abundance and diversity of microorganisms in the biosphere reflects their ability to accumulate energy from various organic and inorganic substrates as well as the ability to grow in a wide range of natural conditions. Most often, the complexity of microbial communities is dependent on the conditions offered by the habitat for its colonization and the availability for energy and carbon sources. In most cases, habitats offer extreme climatic or environmental conditions, thus limiting the number of species that may exist in such an ecological niche. An example of such natural selection can be found in endolytic habitats which are colonized by microorganisms involved in their biodegradation or biodeterioration. This paper is a holistic approach to such microorganisms and the types of substrates they can colonize
J. Madden, Gabriela Marcano, Stephen Taylor et al.
Proceedings of the 20th ACM Conference on Embedded Networked Sensor Systems · 2022
Soil microbial fuel cells are a promising source of energy for outdoor sensor networks. These biological systems are sensitive to environmental conditions, therefore more data is needed on their behavior "in the wild" to enable the creation of an energy system capable of being widely deployed. Prior work on early characterization of microbial fuel cells relied on extremely accurate, but expensive, logging hardware. To scale up the number of deployment sites, we present custom logging hardware, specially designed to accurately monitor the behavior of microbial fuel cells at low cost. This paper describes the design and evaluation of the board, which is open source and freely available on GitHub.
Yang Yang, Lei Wang, Yuanqi Wang et al.
Proceedings of the 2018 International Conference on Electronics and Electrical Engineering Technology · 2018
Microbial power generation is the use of microbial energy to generate electricity. This paper is mainly designed to study the microbial power generation system in the energy storage system. Microbial power generation voltage is only 0.6v and this voltage is very small, The electricity from the microbes is first charged by a group of parallel super capacitors. Then the super capacitor is transformed into a series state, and then through the DC-DC boost circuit to store electricity. This can store electricity exponentially and Long time power supply for load. This process, the switching of the series and parallel state of the super capacitor is controlled by a single cylinder which is connected with the circuit. The whole system can raise the voltage of microbes from 0.6V to 15V.In addition, the energy storage scheme discussed in this paper has practical guiding significance, and can guide the production of the corresponding objects.
Boyu Ma
Second International Conference on Biological Engineering and Medical Science (ICBioMed 2022) · 2023
Microorganism is an important part of soil ecosystem and the main promoter of biosphere material circulation and energy flow. It plays an important role in biogeochemical cycles such as decomposition of soil organic matter, nutrient release and energy transfer. Its diversity directly affects soil quality and determines whether crops can grow healthily. In this research, various research methods of soil microbial diversity were reviewed, and the advantages and disadvantages of each method were compared. At the same time, some views on the shortcomings and development of microbial diversity research were put forward. The main research methods of soil microbial diversity were introduced in order to provide theoretical basis for soil microbial research.
Taylor L. Davis, Blake Dirks, Elvis A. Carnero et al.
medRxiv · 2025
Abstract Colonic microorganisms have been linked to human health and disease, specifically metabolic disease states such as obesity, but causal relationships remain to be established. Previous work demonstrated that interactions between the host’s diet and intestinal microbiome were associated with human energy balance by affecting the human’s energy absorption, quantified by metabolizable energy. We developed the Digestion, Absorption and Microbial Metabolism (DAMM) model, which explicitly accounts for the energy contributions of the colonic microbial community by: 1) breaking down the diet composition into the gross energy of the individual macronutrients, 2) calculating direct absorption in the upper gastrointestinal tract, 3) using microbial stoichiometry to estimate the consumption of the remaining unabsorbed nutrients by microbes in the large intestine, 4) quantifying predicted production of microbial products (short-chain fatty acids (SCFA) and methane) in the colon, and 5) estimating absorption from the colonic tract to the host. When used to predict the results from a clinical study that compared two distinctly different diets, the DAMM model captured the directionality and magnitude of change in measured metabolizable chemical oxygen demand (which can be converted to metabolizable energy), improved on the accuracy of predictions compared to the Atwater factors by reducing systematic bias on one of the diets, and estimated substrate availability within the colon and rate of production of microbially derived short-chain fatty acids. Measured methane concentrations, combined with findings from the DAMM model, support the hypothesis that methanogens accumulated in mucosal biofilms in participants harboring methanogens. Model outputs also support that colonic transit time directly influenced SCFA absorption rates. The DAMM model now can be linked to existing human models that predict changes in body energy stores to extend our understanding of how microbial metabolic processes affect macronutrient absorption and metabolizable energy.