Chunjun Zhan, Xiaowei Li, Yankun Yang et al.

Biotechnology and Bioengineering • 2021

As alternatives to traditional fermentation substrates, methanol (CH3OH), carbon dioxide (CO2) and methane (CH4) represent promising one‐carbon (C1) sources that are readily available at low‐cost and share similar metabolic pathway. Of these C1 compounds, methanol is used as a carbon and energy source by native methylotrophs, and can be obtained from CO2 and CH4 by chemical catalysis. Therefore, constructing and rewiring methanol utilization pathways may enable the use of one‐carbon sources for microbial fermentations. Recent bioengineering efforts have shown that both native and nonnative methylotrophic organisms can be engineered to convert methanol, together with other carbon sources, into biofuels and other commodity chemicals. However, many challenges remain and must be overcome before industrial‐scale bioprocessing can be established using these engineered cell refineries. Here, we provide a comprehensive summary and comparison of methanol metabolic pathways from different methylotrophs, followed by a review of recent progress in engineering methanol metabolic pathways in vitro and in vivo to produce chemicals. We discuss the major challenges associated with establishing efficient methanol metabolic pathways in microbial cells, and propose improved designs for future engineering.

Peter Q Fischer, I. Sánchez-Andrea, A. Stams et al.

Environmental Microbiology • 2021

Summary Methanol is an ubiquitous compound that plays a role in microbial processes as a carbon and energy source, intermediate in metabolic processes or as end product in fermentation. In anoxic environments, methanol can act as the sole carbon and energy source for several guilds of microorganisms: sulfate‐reducing microorganisms, nitrate‐reducing microorganisms, acetogens and methanogens. In marine sediments, these guilds compete for methanol as their common substrate, employing different biochemical pathways. In this review, we will give an overview of current knowledge of the various ways in which methanol reaches marine sediments, the ecology of microorganisms capable of utilizing methanol and their metabolism. Furthermore, through a metagenomic analysis, we shed light on the unknown diversity of methanol utilizers in marine sediments which is yet to be explored.

Nur Shahirah Mohd. Aripen Zuraidah Rasep, Amelia Md. Som Aida Safina Arida, Norilhamiah Yahya Mohd. Syazwan Mohd. Ghazali

Journal of Environmental Science and Technology • 2016

Microbial Fuel Cell (MFC) is a bio-electrochemical system that drives a current by using bacteria and mimicking bacterial interactions found in nature. This study was conducted to investigate the efficiency of MFC for electricity generation and removal of Chemical Oxygen Demand (COD). This research also study the effect of several parameters such as electrode sizes and type of microbial fuel cell on the performance of MFC. This study was carried out by using single and double chamber MFC. In effect, on electrode size, the 8×8 cm gives the highest maximum current generation which is 0.72 mA and highest COD removal efficiency of 62.96%. For effect of types MFC, single chamber microbial fuel cell gives the highest maximum current generation which is 0.78 mA and highest COD removal efficiency of 64.20%. This result shows that, MFC from food wastewater can convert chemical energy to electrical energy. DOI: 10.3923/jest.2016.481.485

Han Sun, Weiyang Zhao, Xuemei Mao et al.

Biotechnology for Biofuels • 2018

Microalgae are capable of producing sustainable bioproducts and biofuels by using carbon dioxide or other carbon substances in various cultivation modes. It is of great significance to exploit microalgae for the economical viability of biofuels and the revenues from high-value bioproducts. However, the industrial performance of microalgae is still challenged with potential conflict between cost of microalgae cultivation and revenues from them, which is mainly ascribed to the lack of comprehensive understanding of carbon metabolism and energy conversion. In this review, we provide an overview of the recent advances in carbon and energy fluxes of light-dependent reaction, Calvin–Benson–Bassham cycle, tricarboxylic acid cycle, glycolysis pathway and processes of product biosynthesis in microalgae, with focus on the increased photosynthetic and carbon efficiencies. Recent strategies for the enhanced production of bioproducts and biofuels from microalgae are discussed in detail. Approaches to alter microbial physiology by controlling light, nutrient and other environmental conditions have the advantages of increasing biomass concentration and product yield through the efficient carbon conversion. Engineering strategies by regulating carbon partitioning and energy route are capable of improving the efficiencies of photosynthesis and carbon conversion, which consequently realize high-value biomass. The coordination of carbon and energy fluxes is emerging as the potential strategy to increase efficiency of carbon fixation and product biosynthesis. To achieve more desirable high-value products, coordination of multi-stage cultivation with engineering and stress-based strategies occupies significant positions in a long term.

M. Esfandyari, D. Jafari, Hamed Azami

Biofuels • 2023

Abstract Microbial fuel cells (MFCs) have emerged as a promising technology for the sustainable wastewater treatment and simultaneous recovery of energy. MFCs enable the direct conversion of organic matter in wastewater into electricity using the metabolic activity of exoelectrogenic bacteria through a bio-electrochemical process. Several feasibility studies have demonstrated the ability of MFCs to produce electricity efficiently while treating wastewater and validated their potential application. However, further optimization is still required to address the technological and economic challenges associated with scaling up of MFC systems, such as membrane performance and capital costs. This review examines the fundamental principles and applications of MFCs for power generation and sludge remediation. Key factors which influence the MFCs’ efficiency, including electrode design and microbial communities, are also discussed. While MFCs have served as a cost-effective solution for integrated wastewater management and renewable energy recovery, additional research is needed to enhance their system designs and facilitate their commercial adoption.

Matheus Sanitá Lima, Rosymar Coutinho de Lucas

Frontiers in Microbiology • 2022

Sixty years have passed since Rachel Carson published her seminal book “Silent Spring” (Carson, 1962). Her work catapulted the ecological movement and shapedmodern environmentalism (Kroll, 2001). However, fast-forward to present day and we seem not to have paid enough attention to the environment. Guidelines for a sustainable future have been repeatedly proposed and the planetary boundaries for our safe existence have been established (Rockström et al., 2009). Yet, more than 80% of the current global energy consumption still relies on unsustainable fossil fuels1 (Ritchie and Roser, 2020) and the COP26 negotiations have not delivered (Sheather, 2021). To make things worse, the demand for oil and gas is expected to peak in the next two decades.2 The prevailing linear economy based on the take-make-dispose system is unsustainable (Sariatli, 2017) and climate change already affects biological systems around the globe (Freitas et al., 2021). There will not be a “one-stop shop” type of solution, but we need to transition to a circular economy and biorefineries are a great place to start (Ubando et al., 2020). Among several models, the lignocellulosic biorefinery concept is prominent (Silva et al., 2018) and this is where fungi occupy a special place.

Xin Zhou, Fengting Lv, Yiming Huang et al.

Chemistry – A European Journal • 2020

Bioelectrochemical systems (BESs) provide favorable opportunities for the sustainable conversion of energy from biological metabolism. Biological photovoltaics (BPVs) and microbial fuel cells (MFCs) respectively realize the conversion of renewable solar energy and bioenergy into electrical energy by utilizing electroactive biological extracellular electron transfer, however, along with this energy conversion progress, relatively poor durability and low output performance are challenges as well as opportunities. Advances in improving bio-electrode interface compatibility will help to solve the problem of insufficient performance and further have a far-reaching impact on the development of bioelectronics. Conjugated polymers (CPs) with specific optical and electrical properties (absorption and emission spectra, energy band structure and electrical conductivity) afforded by π-conjugated backbones are conducive to enhancing the electron generation and output capacity of electroactive organisms. Furthermore, the water solubility, functionality, biocompatibility and mechanical properties optimized through appropriate modification of side chain provide a more adaptive contact interface between biomaterials and electrodes. In this minireview, we summarize the prominent contributions of CPs in the aspect of augmenting the photovoltaic response of BPVs and power supply of MFCs, and specifically discussed the role of CPs with expectation to provide inspirations for the design of bioelectronic devices in the future.

M. A. Costa de Oliveira, Pedro Pablo Machado Pico, Williane da Silva Freitas et al.

Applied Sciences • 2020

In this work, we synthesized new materials based on Fe(II) phthalocyanine (FePc), urea and carbon black pearls (BP), called Fe-N-C, as electrocatalysts for the oxygen reduction reaction (ORR) in neutral solution. The electrocatalysts were prepared by combining ball-milling and pyrolysis treatments, which affected the electrochemical surface area (ECSA) and electrocatalytic activity toward ORR, and stability was evaluated by cyclic voltammetry and chronoamperometry. Ball-milling allowed us to increase the ECSA, and the ORR activity as compared to the Fe-N-C sample obtained without any ball-milling. The effect of a subsequent pyrolysis treatment after ball-milling further improved the electrocatalytic stability of the materials. The set of results indicated that combining ball-milling time and pyrolysis treatments allowed us to obtain Fe-N-C catalysts with high catalytic activity toward ORR and stability which makes them suitable for microbial fuel cell applications.

Nooruddeen Jabbar, S. Alardhi, Thaer M. Al-Jadir et al.

Journal of Ecological Engineering • 2023

Microbial fuel cells (MFCs) pertain to a kind of modern technology for the direct conversion of chemical energy in organic matter from wastewaters into electricity during the oxidation of organic substrates. A system of continuous MFC was constructed for the treatment of real petroleum refinery wastewater (PRW). The treatment of real PRW, operational performance of the MFC system, biodegradation of furfural, and energy output were investigated in this study. The MFC was inoculated by mixed anaerobic bacteria, with Bacillus sp. as the dominant type, and continuously operated for 30 days. The biodegradation of furfural and phenol, which are the most prevalent toxicants in refinery wastewater, was investigated. The MFC system reached maximum energy outputs of 552.25 mW/m 3 and 235 mV. In the anodic chamber, the maximum removal of furfural and phenol was higher than 99%, with biodegradation of organic content reaching up to 95%. This study demonstrated the viability of a continuous-flow MFC system as a green technology for the treatment of furfural-rich real refinery effluents while generating electricity.

Yu Niu, Zhiqian Wang, Yingying Xiong et al.

Molecules • 2024

By allowing coal to be converted by microorganisms into products like methane, hydrogen, methanol, ethanol, and other products, current coal deposits can be used effectively, cleanly, and sustainably. The intricacies of in situ microbial coal degradation must be understood in order to develop innovative energy production strategies and economically viable industrial microbial mining. This review covers various forms of conversion (such as the use of MECoM, which converts coal into hydrogen), stresses, and in situ use. There is ongoing discussion regarding the effectiveness of field-scale pilot testing when translated to commercial production. Assessing the applicability and long-term viability of MECoM technology will require addressing these knowledge gaps. Developing suitable nutrition plans and utilizing lab-generated data in the field are examples of this. Also, we recommend directions for future study to maximize methane production from coal. Microbial coal conversion technology needs to be successful in order to be resolved and to be a viable, sustainable energy source.

Surbhi Jain, James K. Heffernan, Jitendra A. Joshi et al.

Microbiology Australia • 2023

Climate change and food security are two of our most significant global challenges of our time. Conventional approaches for food production not only produce greenhouse gases but also require extensive land and water resources. An alternative is to use gas fermentation to convert greenhouse gases as feedstocks into microbial protein-rich biomass (single-cell protein). Aerobic methanotrophic (methane-oxidising) and hydrogenotrophic (hydrogen-oxidising) bacteria, which produce biomass using gases as their energy and carbon sources, are ideal candidates for single-cell protein production. However, multiple innovations are required for single-cell protein production to be economical and sustainable. Although current technologies rely on conversion of purified single gaseous substrates, the potential to directly use mixed gas streams from point sources remains reasonably unexplored. In addition, there is much potential to increase nutritional and commercial value of single-cell protein through synthetic biology. In this perspective, we discuss the principles, approaches, and outlook for gas fermentation technologies aiming to significantly reduce greenhouse gas emissions and enhance food security.

Swati Das, R. Raj, M. Ghangrekar

Green Chemistry • 2023

Third-generation biodiesel produced using carbon-neutral algal feedstock is a promising alternative to meet global energy demands. However, the economic viability of algae-derived biodiesel is severely impacted by poor lipid recovery...

Irwan Ibrahim, M. Salehmin, Krishan Balachandran et al.

Frontiers in Microbiology • 2023

Microbial electrosynthesis (MES) is an emerging electrochemical technology currently being researched as a CO2 sequestration method to address climate change. MES can convert CO2 from pollution or waste materials into various carbon compounds with low energy requirements using electrogenic microbes as biocatalysts. However, the critical component in this technology, the cathode, still needs to perform more effectively than other conventional CO2 reduction methods because of poor selectivity, complex metabolism pathways of microbes, and high material cost. These characteristics lead to the weak interactions of microbes and cathode electrocatalytic activities. These approaches range from cathode modification using conventional engineering approaches to new fabrication methods. Aside from cathode development, the operating procedure also plays a critical function and strategy to optimize electrosynthesis production in reducing operating costs, such as hybridization and integration of MES. If this technology could be realized, it would offer a new way to utilize excess CO2 from industries and generate profitable commodities in the future to replace fossil fuel-derived products. In recent years, several potential approaches have been tested and studied to boost the capabilities of CO2-reducing bio-cathodes regarding surface morphology, current density, and biocompatibility, which would be further elaborated. This compilation aims to showcase that the achievements of MES have significantly improved and the future direction this is going with some recommendations. Highlights – MES approach in carbon sequestration using the biotic component. – The role of microbes as biocatalysts in MES and their metabolic pathways are discussed. – Methods and materials used to modify biocathode for enhancing CO2 reduction are presented.

K. Abdulwahab, M. Khan, J. R. Jennings

Critical Reviews in Solid State and Materials Sciences • 2023

Abstract Ferrites and ferrite-based composites are known for their fascinating magnetic properties, varied redox chemistry, good stability, and excellent catalytic properties, all of which make them useful for a growing range of energy-related applications. The present review provides a concise summary of the basic properties of ferrites, an overview of the applicable synthetic methods, and recent advances related to the application of ferrites and ferrite-based composites in photoelectrochemical cells, photocatalytic CO2 reduction, batteries, supercapacitors, and microbial fuel cells. Special emphasis is placed on materials prepared by modern techniques, including microwave-assisted synthesis, ultrasound-assisted and sonochemical methods, synthesis employing metal-organic framework precursors, and electrospinning methods. The effects of intrinsic magnetism and external magnetic fields on the efficiency of ferrites in selected energy applications are also highlighted. The review concludes with a future outlook for the field that proffers solutions to issues currently hindering the effective utilization of ferrites and ferrite-based composites in energy conversion and storage applications. Graphical Abstract Highlights Overview of the preparation and electrochemical energy applications of ferrites and ferrite-based composites Recent applications of ferrites in photoelectrochemical cells, photocatalytic CO2 reduction, batteries, supercapacitors, and microbial fuel cells Effect of magnetism and external magnetic fields on the synthesis and electrochemical applications of ferrites

G. Massaglia, M. Quaglio

Energy Conversion - Current Technologies and Future Trends • 2018

This chapter book aims to present some key aspects, which play a crucial role to optimize the energy conversion process occurring in microbial fuel cells (MFCs): fluid dynamics and the materials selected as anodic electrodes. MFCs are (bio)-electrochemical devices that directly convert chemical energy into electrical energy, thanks to the metabolic activity of some bacteria. In the anodic compartment, these bacteria, named exoelectrogens, are able to oxidize the organic matter, directly releasing the electrons to the anode surface. The conversion process can be deeply influenced by how the electrolyte solution, containing the carbon-energy source, moves inside the device. For this reason, fluid dynamic modeling is an important tool to explain the correlation between the fluid flow and power output production, optimizing also the overall MFC performance. Moreover, the morphology of anode electrodes results to be essential to guarantee and enhance the bacteria proliferation on them, improving the energy conversion.

H. Schlegel, J. Barnea

• 1976

Proceedings of a seminar on microbial energy conversion organized under the auspices of the Gesellschaft fur Strahlem-und Umweltforschung, sponsored by the United Nations Institute for Training and Research and the Ministry for Research and Technology of the Federal Republic of Germany and held at the Institut fur Mikrobiologie, Gottingen. Experts and observers in the fields of microbiology, bio-technology, chemistry, economics and sociology from seventeen countries attended this seminar the aim of which was to review biomass production and to discuss in detail those microbial processes involved in the conversion of the primary biomass. In addition to the thirty-eight papers presented at the seminar, this volume contains the recommendations concerning future research and development put forward by working groups on: biomass; recycling of wastes; methane production; photoproduction of hydrogen/purple membrane; microbial recovery of hydrocarbons; prices of important substrates and economics of chemical interconversions.

Jun Cheng, Kefa Cen

Carbon Neutrality • 2022

Abstract The goals of national energy security and sustainable development necessitate the role of renewable energy, of which biomass energy is an essential choice for realizing the strategic energy diversification and building a low-carbon energy system. Microbial conversion of flue-gas-derived CO 2 for producing biodiesel and biogas has been considered a significant technology in new energy development. Microalgae carbon sequestration is a hot research direction for researchers. However, three fundamental problems relating to energy/mass transfer and conversion remain as follows: (1) contradictory relationship between high resistance of cell membrane micropores and high flux of flue-gas-derived CO 2 limits mass transfer rate of CO 2 molecules across cell membrane; (2) low biocatalytic activity of intracellular enzymes with high-concentration CO 2 results in difficulties in directional carbon/hydrogen conversion; (3) competition between multiple intracellular reaction pathways and high energy barriers of target products hinder the desirable cascade energy transfer. Therefore, key scientific issues of microbial energy conversion lie in the understanding on directional carbon/hydrogen conversion and desirable cascade energy transfer. Multiple researches have established a theoretical foundation of microbial energy conversion which strengthens energy/mass transfer in microbial cells. The innovative results in previous studies have been obtained as follows: (1) Reveal mass transfer mechanism of vortex flow across cell membrane micropores. (2) Propose a strategy that directionally regulates enzyme activity. (3) Establish chain reaction pathways coupled with step changes.

Rehab H. Mahmoud, Farag A. Samhan, Mohamed K. Ibrahim et al.

Electrochemical Science Advances • 2022

Abstract Increasing environmental pollution along with the depletion of energy resources are critical challenges. Microbial fuel cells (MFCs), a simple fuel cell that converts chemical energy into bioelectricity by the catalytic activities of living microbes, are evolving as a multipurpose renewable energy technology. The power generation via the MFCs depends on harvesting free electrons from the electroactive microorganisms, popularly known as exoelectrogens, to simultaneously produce electricity and treat wastewater. In the present work, nanostructured bio‐electrochemical systems are designed to exploit the usability of algae biomass collected from high rate algal pond system (HRAP) either as algal‐living cells or as dry biomass for bioelectricity production via several approaches (i.e., the algae will act as bioanode, biocathode, or nutrient substrate). The obtained results indicated that a higher electric current is produced when microalgae living cells are exploited as bio‐cathode in a double‐chamber‐microbial fuel cell (DCMFC) with a net power density (250 mW/m 2 ) combined with high‐efficiency removal of COD reached 44.8%. Overall, the study's findings suggested that living algal cells from HRAP support high power output from a DMFC when they are exploited as biocathode, hence, the system introduced the opportunity to redesign the high rate algal ponds in the wastewater treatment plants in a way to produce energy plus the main assigned tasks which are the removal of wastes.

Yingying Li, Jian Zhang, Xiulai Chen

Energy & Environmental Science • 2024

This review comprehensively discusses microbial conversion of CO 2 to organic compounds. The efficiency of CO 2 fixation can be improved by mining CO 2 -fixing enzymes, developing CO 2 -fixing pathways and optimizing CO 2 -fixing microbial cell factories.

Zhenyu Wang, Xiaoyu Zhang, Hao Wang

Energy Conversion and Economics • 2021

Abstract In smart grids, distributed energy resources (DERs) have penetrated residential zones to provide a new form of electricity supply, mainly from renewable energy. Residential households and commercial buildings with DERs have become prosumers in local grids because they can sell surplus power to others. Research has been initiated to integrate and utilize DERs through better control and communication strategies. With the advances in the Internet of Things (IoT) technology, unprecedented coordination among DERs can be achieved to facilitate energy trading and transactive energy management. However, preventing leakage of user information during the optimization process remains a challenge for researchers, which drives them to develop privacy‐preserving energy management systems. In this study, a fully decentralized transactive energy management method using a consensus‐based algorithm is developed. Specifically, a virtual pool is designed for prosumers to trade energy and exchange information with the support of IoT technologies. The consensus‐based algorithm enables prosumers to obtain an optimal energy schedule independently in a coordinated manner without revealing any personal data. Practical data was used to perform simulations and validate the proposed algorithm. The results showed that the authors' consensus‐based decentralized transactive energy management strategy is feasible and can significantly reduce the overall system cost.

Subrata Karmakar

Advanced Energy Conversion Materials • 2024

This tutorial review focuses on the basic theoretical backgrounds, their working principles, and the implementation of impedance spectroscopy in both electroceramics and electrochemical research and technological applications. Various contributions to the impedance, admittance, dielectric, and conductivity characteristics of electroceramics materials can be disentangled and independently characterized with the help of impedance spectroscopy as a function of frequency and temperature. In polycrystalline materials, the impedance, charge transport/conduction mechanism, and the macroscopic dielectric properties, i.e., dielectric constant and loss are typically composed of many contributions, including the bulk or grain resistance/capacitance, grain boundary, and sample-electrode interface effect. Similarly, electrochemical impedance spectroscopy (EIS) endeavors to the charging kinetics, diffusion, and mechanical impact of various electrochemical systems widely used in energy storage (i.e., supercapacitor, battery), corrosion resistance, chemical and bio-sensing, diagnostics, etc., in electrolytes as a function of frequency. The understanding of various contributions in the EIS spectra, i.e., kinetic control, mass control, and diffusion control is essential for their practical implications. It is demonstrated that electrochemical and electroceramics impedance spectroscopy is an effective method to explain and simulate such behavior. Deconvolution these contributions obtains a detailed understanding of the functionality of polycrystalline electroceramic materials. This short review aims to provide the necessary background information for junior researchers working in these fields and allows readers to quickly comprehend the fundamental understanding in this field by saving their time and understanding, and applying impedance spectroscopy in their future projects.

Great Iruoghene Edo

Advanced Energy Conversion Materials • 2023

The scientific and public debate centers on the specific policies that make up the energy transition policy, as well as issues surrounding how they interact and fit into the European context. The Federal Government of Germany came to a conclusion to change the existing structure of the country's energy supply system by ending nuclear energy conversion and strongly promoting the development of renewable energies. It is been seen that briefly after the Fukushima Daiichi nuclear disaster in Japan in 2011, it is seen the Federal Government of Germany came to a conclusion to change the existing structure of the country's energy supply system by ending nuclear energy conversion and strongly promoting the development of renewable energies. This paper aims at reviewing the past, present, and future of energy in Germany. It provides an overview of the historical trends of energy in Germany under energy use (kg of oil equivalent per capita), fossil fuel energy consumption (% of total), renewable energy development, and evolution of renewable energy patents. The requirements of such a system are not satisfied by policy approaches or recommendations that target short-term effects or that are perceptions of problems extrapolated from individual sectors. By collecting information from the literatures, it analyses current energy issues in Germany and the future of energy in Germany. This paper tends to bring to understanding the state of energy in Germany.

Abdalla M Abdalla, Bassem E. Elnaghi, Shahzad Hossain et al.

Advanced Energy Conversion Materials • 2020

World needs have revolved around the use of nanotechnology in most vital applications especially in the energy sector. From which has a major role in the application of this technology in several aspects as the conversion of energy, the storage of energy and efficiency of energy. Through the ongoing research by scientists and researchers to incorporate nanotechnology as one of the essential technologies at present and in the future, which has shown the strength of nanotechnology in reaching the possible superior efficiency. In this review, we present various important applications of nanotechnology involved in the three main directions (energy conversion, energy storage and energy efficiency). These ultimate goals of the nanotechnology utilization in the energy sector will offer the high demand of energy efficiency with minimum losses and high durability in the clean and sustainable resources.

Mohammad A A Al-Najjar, Dirk de Beer, Bo Barker Jørgensen et al.

The ISME Journal • 2010

Abstract Here we present, to the best of our knowledge, the first balanced light energy budget for a benthic microbial mat ecosystem, and show how the budget and the spatial distribution of the local photosynthetic efficiencies within the euphotic zone depend on the absorbed irradiance (Jabs). Our approach uses microscale measurements of the rates of heat dissipation, gross photosynthesis and light absorption in the system, and a model describing light propagation and conversion in a scattering–absorbing medium. The energy budget was dominated by heat dissipation on the expense of photosynthesis: in light-limiting conditions, 95.5% of the absorbed light energy dissipated as heat and 4.5% was channeled into photosynthesis. This energy disproportionation changed in favor of heat dissipation at increasing irradiance, with >99% of the absorbed light energy being dissipated as heat and <1% used by photosynthesis at Jabs>700 μmol photon m−2 s−1 (>150 J m−2 s−1). Maximum photosynthetic efficiencies varied with depth in the euphotic zone between 0.014−0.047 O2 per photon. Owing to steep light gradients, photosynthetic efficiencies varied differently with increasing irradiances at different depths in the euphotic zone; for example, at Jabs>700 μmol photon m−2 s−1, they reached around 10% of the maximum values at depths 0−0.3 mm and progressively increased toward 100% below 0.3 mm. This study provides the base for addressing, in much more detail, the photobiology of densely populated photosynthetic systems with intense absorption and scattering. Furthermore, our analysis has promising applications in other areas of photosynthesis research, such as plant biology and biotechnology.

Chad Nielsen, Asif Rahman, Asad Ur Rehman et al.

Microbial Biotechnology • 2017

Summary Polyhydroxyalkanoates (PHAs) are biopolymers with desirable material properties similar to petrochemically derived plastics. PHAs are naturally produced by a wide range of microorganisms as a carbon storage mechanism and can accumulate to significantly high levels. PHAs are an environmentally friendly alternative to their petroleum counterparts because they can be easily degraded, potentially reducing the burden on municipal waste systems. Nevertheless, widespread use of PHAs is not currently realistic due to a variety of factors. One of the major constraints of large‐scale PHA production is the cost of carbon substrate for PHA‐producing microbes. The cost of production could potentially be reduced with the use of waste carbon from food‐related processes. Food wastage is a global issue and therefore harbours immense potential to create valuable bioproducts. This article's main focus is to examine the state of the art of converting food‐derived waste into carbon substrates for microbial metabolism and subsequent conversion into PHAs.

R. Paul Aftring, Barrie F. Taylor

Applied and Environmental Microbiology • 1979

A project to investigate biofouling, under conditions relevant to ocean thermal energy conversion heat exchangers, was conducted during July through September 1977 at a site about 13 km north of St. Croix (U.S. Virgin Islands). Seawater was drawn from a depth of 20 m, within the surface mixed layer, through aluminum pipes (2.6 m long, 2.5-cm internal diameter) at flow velocities of about 0.9 and 1.8 m/s. The temperature of the seawater entering the mock heat exchanger units was between 27.8 and 28.6°C. After about 10 weeks of exposure to seawater, when their thermal conductivity was reported to be significantly impaired, the pipes were assayed for the accumulation of biological material on their inner surfaces. The extent of biofouling was very low and independent of flow velocity. Bacterial populations, determined from plate counts, were about 10 7 cells per cm 2 . The ranges of mean areal densities for other biological components were: organic carbon, 18 to 27 μg/cm 2 ; organic nitrogen, 1.5 to 3.0 μg/cm 2 ; adenosine 5′-triphosphate, 4 to 28 ng/cm 2 ; carbohydrate (as glucose in the phenol assay), 3.8 to 7.0 μg/cm 2 ; chlorophyll a , 0.2 to 0.8 ng/cm 2 . It was estimated from the adenosine 5′-triphosphate and nitrogen contents that the layer of live bacteria present after 10 weeks was only of the order of 1μm thick. The C/N ratio of the biological material suggested the presence of extracellular polysaccharidic material. Such compounds, because of their water-retaining capacities, could account for the related increase in thermal resistance associated with the pipes. This possibility merits further investigation, but the current results emphasize the minor degree of biofouling which is likely to be permissible in ocean thermal energy conversion heat exchangers.

Moumita Roy, Sukrampal Yadav, Sunil A. Patil

Frontiers in Energy Research • 2021

Biogas is one of the promising futuristic renewable energy sources with enormous market potential. However, the presence of CO 2 lowers down the calorific value of biogas. Hence, various biogas upgradation technologies are under intense investigation to increase the methane content to the desired level. This study reports on enhancing methane content in biogas through CO 2 sequestration into acetic acid via microbial electrosynthesis (MES) process. The previously enriched mixed chemolithoautotrophic microbial culture dominated by Acetobacterium spp. used CO 2 present in the biogas as the sole carbon source. After establishing a stable performing biocathode at a fixed cathodic potential of −1 V (vs. Ag/AgCl) through batch mode operation, biogas was fed continuously at different feed rates, viz ., 0.5, 0.3, and 0.2 ml/min to the cathode chamber. The highest feed rate of 0.5 ml/min was least effective both for methane content increment (from 61 ± 3% to 86 ± 2%) and acetic acid titer (1.5 ± 0.5 g/L; 0.107 ± 0.02 g/L/d.). In comparison, the lowest flow rate of 0.2 ml/min was the most effective for the intended process (methane upgradation from 62 ± 7% to 93 ± 3% and acetic acid titer 3.4 ± 0.6 g/L produced at 0.24 ± 0.04 g/L/d rate). Both acetic acid bioproduction and biogas upgradation occurred best at an E cell of 3.3 ± 0.35 V at the low feed rate. A maximum of 84 ± 7%, 57 ± 10% and 29 ± 2% coulombic, carbon and energetic efficiencies, respectively, were achieved in acetic acid. Cyclic voltammograms of biocathodes revealed the decrease in hydrogen evolution potential and increased bioelectrocatalysis, thereby suggesting the contribution of microbes in the process. Acetobacterium , which is known for CO 2 fixation, was found to be the dominant microbial genus in biogas fed reactors. The demonstrated approach not only offers the advantage of obtaining two products, one in the bulk phase and the other in the off-gas, it also validates the applicability of the bioelectrochemical biogas upgradation technology.

Alexander Connor, Jessica V. Lamb, Massimiliano Delferro et al.

Microbial Cell Factories • 2023

Abstract Background The increasing prevalence of plastic waste combined with the inefficiencies of mechanical recycling has inspired interest in processes that can convert these waste streams into value-added biomaterials. To date, the microbial conversion of plastic substrates into biomaterials has been predominantly limited to polyhydroxyalkanoates production. Expanding the capabilities of these microbial conversion platforms to include a greater diversity of products generated from plastic waste streams can serve to promote the adoption of these technologies at a larger scale and encourage a more sustainable materials economy. Results Herein, we report the development of a new strain of Pseudomonas bacteria capable of converting depolymerized polyethylene into high value bespoke recombinant protein products. Using hexadecane, a proxy for depolymerized polyethylene, as a sole carbon nutrient source, we optimized media compositions that facilitate robust biomass growth above 1 × 10 9 cfu/ml, with results suggesting the benefits of lower hydrocarbon concentrations and the use of NH 4 Cl as a nitrogen source. We genomically integrated recombinant genes for green fluorescent protein and spider dragline-inspired silk protein, and we showed their expression in Pseudomonas aeruginosa , reaching titers of approximately 10 mg/L when hexadecane was used as the sole carbon source. Lastly, we demonstrated that chemically depolymerized polyethylene, comprised of a mixture of branched and unbranched alkanes, could be converted into silk protein by Pseudomonas aeruginosa at titers of 11.3 ± 1.1 mg/L. Conclusion This work demonstrates a microbial platform for the conversion of a both alkanes and plastic-derived substrates to recombinant, protein-based materials. The findings in this work can serve as a basis for future endeavors seeking to upcycle recalcitrant plastic wastes into value-added recombinant proteins.

Ariel Yépez-García

• 2017

Energy liberalization is commonly measured by the level of market competitiveness and price reductions. This review applies an alternative method, market power, to give a sense of firms’ pricing behaviors in the electricity generation market. In Both Guatemala and Chile, the ex post simulation approach suggests a slightly larger price markup ratio for firms with larger market share and more diversified generation technologies. Further, in Chile, the policy reform considering electrical supply bidding framework (Law No. 20.805) has been proved tentatively positive towards the mitigation of market power. With the hope of more data availability, this review also explores the possibilities to implement other measures of market power in LAC region as well as the data requirements for different methodologies.

Mahesh P. Bhave

• 2016

What kinds (according to U.S. News & World Report) of clean electricity initiatives—ones that make sense on public policy and business strategy levels—could overcome the hurdles in shifting away from the entrenched electricity and petroleum-based transport industries in the United States? This book explores the tremendous opportunities of the new electricity revolution that looks to threaten the century-old business models of our existing power production infrastructure. The electricity industry, having been in place for more than 100 years, has established tremendous power and influence. But as solar- and wind-based energy businesses gain small footholds and expand their impact, the incumbent electricity businesses face fundamental challenges that threaten their century-old business models. Will technological advances and the motivation to control climate change finally effect a revolution in the electricity markets? This unique book proposes public policy- and business strategy-level initiatives that could overcome the structural impediments that prevail in the current electricity industries and predicts the important changes to come in the immediate and distant future. In The Microgrid Revolution: Business Strategies for Next-Generation Electricity, author Mahesh P. Bhave explains the current state of electricity production, identifies its widespread problems, and proposes a specific approach and particular solution to the puzzle of supplying clean energy for the 21st-century world. The introductory chapters lay the groundwork for the author’s provocative thesis, and the concluding chapters elaborate on it with broad implications. By examining the subject material from the perspectives of public policy and regulatory concerns, corporate strategy, industry structure changes, innovation, and climate change as well as from a technological angle, readers from diverse industries and professional backgrounds will be able to understand how the coming electricity revolution is something we all have the power to influence.

Alisson Dodón, Vanessa Quintero, Miguel Chen Austin et al.

Biomimetics • 2021

This work has its origin in the growing demands of energy regulations to meet future local targets and to propose a global implementation framework. A literature review related to conventional electrical energy storage systems has been carried out, presenting different cases analyzed at building scale to deepen in nature-inspired processes that propose reductions in environmental impact and present improvements in these storage devices. The use of batteries, especially lithium-ion batteries, is the most prominent among the electrical storage applications; however, improvements have been proposed through hydrogen batteries or the implementation of more environmentally friendly materials to manufacture the electrodes. In this sense, oriented to creating systems designed to protect the environment, important advances have been made in the development of storage systems based on biomimetic strategies. The latter range from the generation of energy through the respiratory processes of microorganisms to the recreation of the generation, storage, and release of energy using the thermoelectric and thermoregulatory characteristics of some insects. These facts show that the trend in research towards improving existing systems continues but reinforces the idea that new solutions must be environmentally friendly, so there is still a long way to improving the processes established thus far.

Krzysztof Necka, Małgorzata Trojanowska

BIO Web of Conferences • 2018

The paper presents the results of electricity quality measurements conducted in six agri-food processing plants equipped with receivers of different sensitivity to the quality of the supply voltage. In particular, statistical assessment has been conducted for the value of the parameters characterizing the supply voltage, describing the parameters using the basic statistical measures and comparing them with the normative requirements. The paper also presents examples of the hazards to electrical drives and control systems caused by such industrial electromagnetic interferences as voltage changes or deformations of voltage waveform.

, Engr. Lorinda E. Pascual

Engineering and Technology Journal • 2020

Walking is the most common activity in our daily life. When we walk, we lose energy to the floor surface. Vibration is one form of energy that is transferred from our weight on to the floor surface during every step. This energy can be harvested and converted into electrical energy. This research addressed the design and construction of a power generating floor pad which can be used to harvest electricity from human footsteps. The electric generating floor pad features springs mounted on its four corners. When somebody walks though the surface of the floor pad, the springs will be compressed because of the weight of the person causing it to dip down slightly. The shaft of the permanent magnet generator will rotate then rotate, thus voltage is generated. The generator can be connected to a battery so as to store electrical energy. Test performed on the device indicates that it is capable of converting human footsteps to a useful electrical energy to power small electrical devices. The magnitude of the generated voltage can be maximized by applying more force on the floor pad. The discharging time of the battery is longer when there are more footsteps applied to the floor pad. The device can be conveniently installed in the doorways of buildings or other heavy traffic areas. Through this research project, a new option for harnessing green electricity by footsteps is made available focusing on the use of springs and permanent magnet generators.

, M. Ahsan B. Habib

International Journal of Current Science Research and Review • 2021

An experiment was conducted for the production of protein, bio-fuel and bio-electricity from the culture system of Spirulina platensis (Gomont) in supernatant of three different amount of digested rotten tomato (Solanum lycopersicum), and Kosaric Medium (KM) as control. Three different concentrations such as 25, 50 and 75% rotten tomato were allowed to digest under aeration. After 17 days, the colorless supernatant was screened and taken in 1.0 L conical flask with three replications. Then, Spirulina platensis was inoculated to grow in these three media (treatments) with the addition of 9.0 g/L NaHCO3 and micronutrients, and also in KM as control for a period of 14 days. The cell weight, optical density, chlorophyll a and total biomass of spirulina was attained to the maximum values when grew in KM on the 10th day of culture followed by supernatant of 50% digested rotten tomato (DRT) than in 25 and 75% DRT culture. The chemical properties of the culture media such as pH, salinity, dissolved bio-oxygen, electric conductivity and bio-electricity were increased from first day up to 12th day of experiment. Total biomass of spirulina grown in these media had highly significant (P < 0.01) correlation with cell weight (r = 0.825) and chlorophyll a (r = 0.866) of spirulina. The results showed that the growth performances of S. platensis grown in supernatant of 50% DRT was significantly (P < 0.01) higher than that of spirulina grown in supernatant of 25 and 75% DRT. The percentage of crude protein (55.10 ± 0.45 to 59.90 ± 0.33%) of spirulina grown in supernatant of DRT was little bit higher than that of spirulina cultured in KM (58.40 ± 0.38%). But bio-fuel in terms of crude lipids (16.50 ± 0.31%) of spirulina cultured in supernatant of 50% DRT was almost two and half times higher than that of spirulina grown in KM (crude lipids, 6.30 ± 0.21%). Bio-electricity (300 ±10.20 mV) produced in culture of spirulina in supernatant of 50% DRT was higher than that recorded in KM (240 ±10.20 mV) followed by 75% DRT and other media. Bio-electricity had directly and strongly significant (p < 0.001) correlation with pH (r = 0.812), dissolved bio-oxygen (r = 0.832), salinity (r = 0.788) and electric conductivity (r = 0.856). Therefore, this procedure will produce huge amount of electricity in the world and will make a revolution in this field of bio-electricity production. Whole world will be benefited from the output (results) of this experiment.

Ebtehag A. E. Sakr, Dena Z. Khater, Kamel M. El‑khatib

Journal of Nanobiotechnology • 2024

Abstract In this study, highly selenite-resistant strains belonging to Brevundimonas diminuta (OK287021, OK287022) genus were isolated from previously operated single chamber microbial fuel cell (SCMFC). The central composite design showed that the B. diminuta consortium could reduce selenite. Under optimum conditions, 15.38 Log CFU mL -1 microbial growth, 99.08% Se(IV) reduction, and 89.94% chemical oxygen demand (COD) removal were observed. Moreover, the UV–visible spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) analyses confirmed the synthesis of elemental selenium nanoparticles (SeNPs). In addition, transmission electron microscopy (TEM) and scanning electron microscope (SEM) revealed the formation of SeNPs nano-spheres. Besides, the bioelectrochemical performance of B. diminuta in the SCMFC illustrated that the maximum power density was higher in the case of selenite SCMFCs than those of the sterile control SCMFCs. Additionally, the bioelectrochemical impedance spectroscopy and cyclic voltammetry characterization illustrated the production of definite extracellular redox mediators that might be involved in the electron transfer progression during the reduction of selenite. In conclusion, B. diminuta whose electrochemical activity has never previously been reported could be a suitable and robust biocatalyst for selenite bioreduction along with wastewater treatment, bioelectricity generation, and economical synthesis of SeNPs in MFCs.

Jed Bailey

• 2012

This study compares the levelized cost of electricity generated with fossil fuels (including coal, natural gas, fuel oil, and diesel) and renewable or carbon-free energy sources (including hydro, wind, solar, nuclear and geothermal). A meta-study of power generation technology capital costs determined the range of capital costs across the various technologies as well as the range of cost estimates for each individual technology from the various data sources that were examined. Applying these capital costs to a range of operating assumption (such as fuel price and plant utilization rate) resulted in a range of levelized cost of electricity for each technology. In addition, the study examined how the cost of electricity was affected by applying a cost for CO2 emissions and a cost to build new transmission infrastructure to link the power plant in question to the national grid. Finally, the study examined the potential investment cost and benefits in reducing CO2 emissions and levelized costs of electricity by repowering existing thermal power plants or switching high-carbon fuels to lower carbon alternatives. This analysis included two case studies: repowering an older natural-gas fired combustion turbine unit in Peru and repowering and fuel switching an oil-fired steam turbine unit to natural gas in Nicaragua.

Abu Yousuf, Pradip Saha, Sreejon Das et al.

Journal of Chemical Engineering • 2014

This study focused on the generation of electricity from whey in a bio-fuel cell (BFC). Whey or Milk Serum is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein in Foods and Sweets Company. It was selected as electrolyte in biofuel cell due to containing higher amount of branched-chain amino acids (BCAA's).The pH value of fresh whey was 3.1-3.8. Three categories of whey were used in the experiments included fresh whey, preserved by thermal treatment and preserved with 2% phenol by volume. It was observed that microorganism growth was zero in the sample with 2% phenol and growth rate was medium in the sample preserved by thermal treatment and that was higher in the fresh sample. In this biofuel cell, voltage was increased with the increase of surface area of electrodes. For a single compartment containing 8 unit cells, resultant voltage and current were 2.86V and 450?A and four compartment 32 unit cells in series, the values were 10.90V and 8.05mA respectively. When anode area was increased to reduce polarization, power generation was initially high but the decreasing rate of power was also elevated. Finally, for commercial electrodes, maximum power and minimum internal resistance were recorded. The maximum Current, Voltage and Power for commercial electrodes in a single compartment containing 10 unit cells were 78mA, 3.88V and 0.30264W respectively. DOI: http://dx.doi.org/10.3329/jce.v28i1.18105 Journal of Chemical Engineering, Vol. 28, No. 1, December 2013: 22-26

Jayanthi Velayudhan, Sangeetha Subramanian

Energies • 2023

A manganese oxide-coated cylindrical graphite cathode with a zinc anode was developed to treat wastewater containing selenite in a dual-chambered microbial fuel cell. COD and selenite removal in the anodic chamber by Bacillus cereus with energy generation were evaluated in batch mode. A manganese dioxide-coated graphite cathode was tested for its surface morphology and chemical composition using scanning electron microscopy and dispersive energy analysis of X-rays. Compared to the non-coated graphite electrode, up to 69% enhancement was observed in the manganese dioxide-coated electrode voltage generation with 150 ppm selenite concentration. The fuel cell achieved a maximum power density of 1.29 W/m2 with 91% selenite reduction and up to 74% COD (initial COD of 120 mg/L) removal for an initial selenite concentration from 100 to 150 ppm. The current study demonstrated the possibility of a modified cathode in enhancing energy generation and the use of microbial fuel cell technology to treat wastewater containing selenite.

John Vourdoubas, Vasiliki K. Skoulou

Studies in Engineering and Technology • 2017

The exploitation of rich in sugars lingo-cellulosic residue of carob pods for bio-ethanol and bio-electricity generation has been investigated. The process could take place in two (2) or three (3) stages including: a) bio-ethanol production originated from carob pods, b) direct exploitation of bio-ethanol to fuel cells for electricity generation, and/or c) steam reforming of ethanol for hydrogen production and exploitation of the produced hydrogen in fuel cells for electricity generation. Surveying the scientific literature it has been found that the production of bio-ethanol from carob pods and electricity fed to the ethanol fuel cells for hydrogen production do not present any technological difficulties. The economic viability of bio-ethanol production from carob pods has not yet been proved and thus commercial plants do not yet exist. The use, however, of direct fed ethanol fuel cells and steam reforming of ethanol for hydrogen production are promising processes which require, however, further research and development (R&D) before reaching demonstration and possibly a commercial scale. Therefore the realization of power generation from carob pods requires initially the investigation and indication of the appropriate solution of various technological problems. This should be done in a way that the whole integrated process would be cost effective. In addition since the carob tree grows in marginal and partly desertified areas mainly around the Mediterranean region, the use of carob’s fruit for power generation via upgrading of its waste by biochemical and electrochemical processes will partly replace fossil fuels generated electricity and will promote sustainability.

Harapriya Pradhan, Omkar A. Shinde, Makarand M. Ghangrekar et al.

Advanced Materials Research • 2015

A new technology called microbial desalination cell (MDC) approaches a comprehensive way to design an innovative system for removal of organic matter and dissolved solids from wastewater. In this study, two laboratory scale MDCs having three chambered (3C-MDC) and five chambered (5C-MDC) configuration were developed for integrated biodegradation of steel plant wastewater. The 3C-MDC have anodic, middle desalination and cathodic chamber; while 5C-MDC have anodic, cathodic, middle desalination and two concentrate chambers separated by ion exchange membranes. Using synthetic saline water with 8 and 30 g/L of TDS and steel plant wastewater (3.74 g TDS/L) in desalination chamber, the TDS removal of 64 ± 2.3%, 75 ± 1.8%, and 58 ± 1.3% were observed in 3C-MDC, while in 5C-MDC, those were 58 ± 1.5%, 71 ± 2.1%, and 64 ± 2.4%, respectively in 96 h of fed batch operation. With 30 g/L of TDS concentration, the power generation observed in 3C-MDC and 5C-MDCs were (81 mW/m 2 and 78 mW/m 2 ) higher than the power observed with 8 g/L (56 mW/m 2 and 45 mW/m 2 ). However, with steel plant wastewater in desalination chamber the power density increased to 76 mW/m 2 in 5C-MDC and significantly decreased to 39 mW/m 2 in 3C-MDC.