Frauke Kracke, Bernardino Virdis, Paul V. Bernhardt et al.

Biotechnology for Biofuels • 2016

Production in acetogenic organisms is usually challenged by cellular energy limitations if the target product does not lead to a net energy gain as in the case of acetate. The presented results demonstrate a significant shift of carbon fluxes away from acetate towards the products, lactate and 2,3-butanediol, induced by small electricity input (~0.09 mol of electrons per mol of substrate). This presents a simple and attractive method to optimize acetogenic fermentations for production of chemicals and fuels using electrochemical techniques. The relationship between metabolic shift and redox potential of electron feed gives an indication of possible electron-transfer mechanisms and helps to prioritize further research efforts.

Jaweria Shamshad, Rashid Ur Rehman

Environmental Science Advances • 2024

Access to clean water is under threat due to population growth, climate change, and pollution, emphasizing the need for effective wastewater treatment.

Maria Ramos-Suarez, Yue Zhang, Victoria Outram

Reviews in Environmental Science and Bio/Technology • 2021

Abstract Volatile fatty acids (VFAs) are key platform chemicals used in a multitude of industries including chemicals, pharmaceuticals, food and agriculture. The current route for VFA production is petrochemical based. VFAs can be biologically produced using organic wastes as substrate, therefore directly contributing to a sustainable economy. This process is commonly known as acidogenic fermentation (AF). This review explores the current research on the development of AF processes optimized for VFA production. Three process steps are considered: feedstock pretreatment, fermentation, and primary product recovery with a focus on in situ recovery. Pretreatment is required for recalcitrant feedstocks, especially lignocellulosic substrates. Different pretreatment techniques for AF application have not been studied in depth. The operational parameters of AF (temperature, pH, hydraulic retention time, substrate concentration, etc.) highly influence microbial activity, VFA yields and product distribution. Optimum conditions are ultimately dependent on substrate composition, however, there is indication that certain operational ranges are beneficial for most feedstocks. VFA recovery and purification are necessary for chemical applications. When recovery is performed in situ, it can help relieve product-induced inhibition and keep alkalinity levels stable enabling further waste degradation. Many techniques have been tested, but none are directly compatible with the fermentation conditions tested. Bio-VFAs have the potential to aid in developing a circular economy, but further development is required. Processes need to be developed with the product market in mind, considering both process integration and systematic process optimization.

Jhuma Sadhukhan, Thomas I. J. Dugmore, Avtar S. Matharu et al.

Sustainability • 2020

Planet Earth is under severe stress from several inter-linked factors mainly associated with rising global population, linear resource consumption, security of resources, unsurmountable waste generation, and social inequality, which unabated will lead to an unsustainable 21st Century. The traditional way products are designed promotes a linear economy that discards recoverable resources and creates negative environmental and social impacts. Here, we suggest multi-disciplinary approaches encompassing chemistry, process engineering and sustainability science, and sustainable solutions in “game changer” challenges in three intersecting arenas of food: Sustainable diet, valorisation of unavoidable food supply chain wastes, and circularity of food value chain systems aligning with the United Nations’ seventeen Sustainable Development Goals. In the arena of sustainable diet, comprehensive life cycle assessment using the global life cycle inventory datasets and recommended daily servings is conducted to rank food choices, covering all food groups from fresh fruits/vegetables, lentils/pulses and grains to livestock, with regard to health and the environment, to emphasise the essence of plant-based diet, especially plant-based sources of protein, for holistic systemic sustainability and stability of the earth system. In the arena of unavoidable food supply chain wastes, economically feasible and synergistically (energy and material) integrated innovative biorefinery systems are suggested to transform unavoidable food waste into functional and platform chemical productions alongside energy vectors: Fuel or combined heat and power generation. In the arena of circularity of food value chain systems, novel materials and methods for plant-based protein functionalisation for food/nutraceutical applications are investigated using regenerative bio-surfactants from unavoidable food waste. This circular economy or industrial symbiosis example thus combines the other two arenas, i.e., plant-based protein sourcing and unavoidable food waste valorisation. The multi-disciplinary analysis here will eventually impact on policies for dietary change, but also contribute knowledge needed by industry and policy makers and raise awareness amongst the population at large for making a better approach to the circular economy of food.

Jian Guo, Yaqin Song, Xiaoyang Ji et al.

Materials • 2019

The aim of this study was to optimize the adsorption performance of activated carbon (AC), derived from the shell of Penaeus vannamei prawns, on heavy metal ions. Inexpensive, non-toxic, and renewable prawn shells were subjected to carbonization and, subsequently, KOH-activation to produce nanoporous K-Ac. Carbonized prawn shells (CPS) and nanoporous KOH-activated carbon (K-Ac) from prawn shells were prepared and characterized by FTIR, XRD, BET, SEM, and TEM. The results showed that as-produced K-Ac samples were a porous material with microporous and mesoporous structures and had a high specific surface area of 3160 m²/g, average pore size of about 10 nm, and large pore volume of 2.38 m³/g. Furthermore, batches of K-Ac samples were employed for testing the adsorption behavior of Cd 2+ in solution. The effects of pH value, initial concentration, and adsorption time on Cd 2+ were systematically investigated. Kinetics and isotherm model analysis of the adsorption of Cd 2+ on K-Ac showed that experimental data were not only consistent with the Langmuir adsorption isotherm, but also well-described by the quasi-first-order model. Finally, the adsorption behaviors of as-prepared K-Ac were also tested in a ternary mixture of heavy metal ions Cu 2+ , Cr 6+ , and Cd 2+ , and the total adsorption amount of 560 mg/g was obtained.

Sanchita Bipin Patwardhan, Soumya Pandit, Piyush Kumar Gupta et al.

Fuel • 2021

The International Biochar Initiative classifies biochar as “a solid material derived from the carbonization of biomass.” Biochar is a solid substance produced during the thermochemical degradation of biomass. This paper describes several examinations that have been conducted to investigate novel utilization of biomass since biochar is affordable, environmentally beneficial, and can be utilized for diverse purposes, such as soil stabilization, wastewater treatment, greenhouse gas management and power generation. Biochar has also been applied in fuel cells and supercapacitors, according to the latest reports. Biochar has the potential to be new and tenable material for microbial fuel cell electrodes. Biochar MFCs made through pyrolysis and gasification, exhibited significant performance as compared to activated carbon and graphite granule. This paper emphasizes the use of biochar as electrodes in MFCs to facilitate the simultaneous treatment of wastewater and electricity generation while also providing additional commercial advantages. Applications of biochar in microbial fuel cells as separator membrane and cathode catalysts are also mentioned. Brief information on the future prospects of the use of biochar in microbial fuel cells is further summarized.

Shun’ichi Ishii, Shino Suzuki, Aaron Tenney et al.

The ISME Journal • 2018

Some microbes can capture energy through redox reactions with electron flow to solid-phase electron acceptors, such as metal-oxides or poised electrodes, via extracellular electron transfer (EET). While diverse oxide minerals, exhibiting different surface redox potentials, are widely distributed on Earth, little is known about how microbes sense and use the minerals. Here we show electrochemical, metabolic, and transcriptional responses of EET-active microbial communities established on poised electrodes to changes in the surface redox potentials (as electron acceptors) and surrounding substrates (as electron donors). Combination of genome-centric stimulus-induced metatranscriptomics and metabolic pathway investigation revealed that nine Geobacter/Pelobacter microbes performed EET activity differently according to their preferable surface potentials and substrates. While the Geobacter/Pelobacter microbes coded numerous numbers of multi-heme c-type cytochromes and conductive e-pili, wide variations in gene expression were seen in response to altering surrounding substrates and surface potentials, accelerating EET via poised electrode or limiting EET via an open circuit system. These flexible responses suggest that a wide variety of EET-active microbes utilizing diverse EET mechanisms may work together to provide such EET-active communities with an impressive ability to handle major changes in surface potential and carbon source availability.

Mohammadreza Kamali, Kenneth M. Persson, Maria Elisabete V. Costa et al.

Environment International • 2019

Application of engineered nanomaterials for the treatment of industrial effluents and to deal with recalcitrant pollutants has been noticeably promoted in recent years. Laboratory, pilot and full-scale studies emphasize the potential of this technology to offer promising treatment options to meet the future needs for clean water resources and to comply with stringent environmental regulations. The technology is now in the stage of being transferred to the real applications. Therefore, the assessment of its performance according to sustainability criteria and their incorporation into the decision-making process is a key task to ensure that long term benefits are achieved from the nano-treatment technologies. In this study, the importance of sustainability criteria for the conventional and novel technologies for the treatment of industrial effluents was determined in a general approach assisted by a fuzzy-Delphi method. The criteria were categorized in technical, economic, environmental and social branches and the current situation of the nanotechnology regarding the criteria was critically discussed. The results indicate that the efficiency and safety are the most important parameters to make sustainable choices for the treatment of industrial effluents. Also, in addition to the need for scaling-up the nanotechnology in various stages, the study on their environmental footprint must continue in deeper scales under expected environmental conditions, in particular the synthesis of engineered nanomaterials and the development of reactors with the ability of recovery and reuse the nanomaterials. This paper will aid to select the most sustainable types of nanomaterials for the real applications and to guide the future studies in this field.

Álvaro Torres-Aravena, Carla Duarte-Nass, Laura Azócar et al.

Crystals • 2018

Microbially induced calcite precipitation (MICP) through a ureolytic pathway is a process that promotes calcite precipitation as a result of the urease enzymatic activity of several microorganisms. It has been studied for different technological applications, such as soil bio-consolidation, bio-cementation, CO2 sequestration, among others. Recently, this process has been proposed as a possible process for removing heavy metals from contaminated soils. However, no research has been reported dealing with the MICP process for heavy metal removal from wastewater/waters. This (re)view proposes to consider to such possibility. The main characteristics of MICP are presented and discussed. The precipitation of heavy metals contained in wastewaters/waters via MICP is exanimated based on process characteristics. Moreover, challenges for its successful implementation are discussed, such as the heavy metal tolerance of inoculum, ammonium release as product of urea hydrolysis, and so on. A semi-continuous operation in two steps (cell growth and bio-precipitation) is proposed. Finally, the wastewater from some typical industries releasing heavy metals are examined, discussing the technical barriers and feasibility.

Xavier Arqué, Adrian Romero‐Rivera, Ferran Feixas et al.

Nature Communications • 2019

Bio-catalytic micro- and nanomotors self-propel by the enzymatic conversion of substrates into products. Despite the advances in the field, the fundamental aspects underlying enzyme-powered self-propulsion have rarely been studied. In this work, we select four enzymes (urease, acetylcholinesterase, glucose oxidase, and aldolase) to be attached on silica microcapsules and study how their turnover number and conformational dynamics affect the self-propulsion, combining both an experimental and molecular dynamics simulations approach. Urease and acetylcholinesterase, the enzymes with higher catalytic rates, are the only enzymes capable of producing active motion. Molecular dynamics simulations reveal that urease and acetylcholinesterase display the highest degree of flexibility near the active site, which could play a role on the catalytic process. We experimentally assess this hypothesis for urease micromotors through competitive inhibition (acetohydroxamic acid) and increasing enzyme rigidity (β-mercaptoethanol). We conclude that the conformational changes are a precondition of urease catalysis, which is essential to generate self-propulsion.

Paul G. Dennis, Bernardino Virdis, Inka Vanwonterghem et al.

Scientific Reports • 2016

Three bioelectrochemical systems were operated with set anode potentials of +300 mV, +550 mV and +800 mV vs. Standard Hydrogen Electrode (SHE) to test the hypothesis that anode potential influences microbial diversity and is positively associated with microbial biomass and activity. Bacterial and archaeal diversity was characterized using 16 S rRNA gene amplicon sequencing, and biofilm thickness was measured as a proxy for biomass. Current production and substrate utilization patterns were used as measures of microbial activity and the mid-point potentials of putative terminal oxidases were assessed using cyclic voltammetry. All measurements were performed after 4, 16, 23, 30 and 38 days. Microbial biomass and activity differed significantly between anode potentials and were lower at the highest potential. Anodic electrode and electrolyte associated community composition was also significantly influenced by anode potential. While biofilms at +800 mV were thinner, transferred less charge and oxidized less substrate than those at lower potentials, they were also associated with putative terminal oxidases with higher mid-point potentials and generated more biomass per unit charge. This indicates that microbes at +800 mV were unable to capitalize on the potential for additional energy gain due to a lack of adaptive traits to high potential solid electron acceptors and/or sensitivity to oxidative stress.

Rediat Abate, Yoong-Sin Oon, Yoong-Ling Oon et al.

Heliyon • 2024

Microalgae and bacteria, known for their resilience, rapid growth, and proximate ecological partnerships, play fundamental roles in environmental and biotechnological advancements. This comprehensive review explores the synergistic interactions between microalgae and bacteria as an innovative approach to address some of the most pressing environmental issues and the demands of clean and renewable freshwater and energy sources. Studies indicated that microalgae-bacteria consortia can considerably enhance the output of biotechnological applications; for instance, various reports showed during wastewater treatment the COD removal efficiency increased by 40%-90.5 % due to microalgae-bacteria consortia, suggesting its great potential amenability in biotechnology. This review critically synthesizes research works on the microalgae and bacteria nexus applied in the advancements of renewable energy generation, with a special focus on biohydrogen, reclamation of wastewater and desalination processes. The mechanisms of underlying interactions, the environmental factors influencing consortia performance, and the challenges and benefits of employing these bio-complexes over traditional methods are also discussed in detail. This paper also evaluates the biotechnological applications of these microorganism consortia for the augmentation of biomass production and the synthesis of valuable biochemicals. Furthermore, the review sheds light on the integration of microalgae-bacteria systems in microbial fuel cells for concurrent energy production, waste treatment, and resource recovery. This review postulates microalgae-bacteria consortia as a sustainable and efficient solution for clean water and energy, providing insights into future research directions and the potential for industrial-scale applications.

Samuel Hansen, Amin Mirkouei, Luis A. Diaz

Renewable and Sustainable Energy Reviews • 2019

Enza Palma, Matteo Daghio, Andrea Franzetti et al.

Microbial Biotechnology • 2017

Groundwater contamination by petroleum hydrocarbons (PHs) is a widespread problem which poses serious environmental and health concerns. Recently, microbial electrochemical technologies (MET) have attracted considerable attention for remediation applications, having the potential to overcome some of the limiting factors of conventional in situ bioremediation systems. So far, field-scale application of MET has been largely hindered by the limited availability of scalable system configurations. Here, we describe the 'bioelectric well' a bioelectrochemical reactor configuration, which can be installed directly within groundwater wells and can be applied for in situ treatment of organic contaminants, such as PHs. A laboratory-scale prototype of the bioelectric well has been set up and operated in continuous-flow regime with phenol as the model contaminant. The best performance was obtained when the system was inoculated with refinery sludge and the anode potentiostatically controlled at +0.2 V versus SHE. Under this condition, the influent phenol (25 mg l -1 ) was nearly completely (99.5 ± 0.4%) removed, with an average degradation rate of 59 ± 3 mg l -1 d and a coulombic efficiency of 104 ± 4%. Microbial community analysis revealed a remarkable enrichment of Geobacter species on the surface of the graphite anode, clearly pointing to a direct involvement of this electro-active bacterium in the current-generating and phenol-oxidizing process.

Jhuma Sadhukhan, Elías Martínez-Hernández, Richard Murphy et al.

Renewable and Sustainable Energy Reviews • 2017

Moumita Roy, Nabin Aryal, Yifeng Zhang et al.

Current Opinion in Green and Sustainable Chemistry • 2022

Francisco Ivars‐Barceló, Alessio Zuliani, Marjan Fallah et al.

Applied Sciences • 2018

A microbial fuel cell (MFC) is a type of bio-electrochemical system with novel features, such as electricity generation, wastewater treatment, and biosensor applications. In recent years, progressive trends in MFC research on its chemical, electrochemical, and microbiological aspects has resulted in its noticeable applications in the field of sensing. This review was consequently aimed to provide an overview of the most interesting new applications of MFCs in sensors, such as providing the required electrical current and power for remote sensors (energy supply device for sensors) and detection of pollutants, biochemical oxygen demand (BOD), and specific DNA strands by MFCs without an external analytical device (self-powered biosensors). Moreover, in this review, procedures of MFC operation as a power supply for pH, temperature, and organic loading rate (OLR) sensors, and also self-powered biosensors of toxicity, pollutants, and BOD have been discussed.

Annette R. Rowe, Farshid Salimijazi, Leah Trutschel et al.

Communications Biology • 2021

Extracellular electron transfer (EET) could enable electron uptake into microbial metabolism for the synthesis of complex, energy dense organic molecules from CO 2 and renewable electricity 1-6 . Theoretically EET could do this with an efficiency comparable to H 2 -oxidation 7,8 but without the need for a volatile intermediate and the problems it causes for scale up 9 . However, significant gaps remain in understanding the mechanism and genetics of electron uptake. For example, studies of electron uptake in electroactive microbes have shown a role for the Mtr EET complex in the electroactive microbe Shewanella oneidensis MR-1 10-14 , though there is substantial variation in the magnitude of effect deletion of these genes has depending on the terminal electron acceptor used. This speaks to the potential for previously uncharacterized and/or differentially utilized genes involved in electron uptake. To address this, we screened gene disruption mutants for 3667 genes, representing ≈99% of all nonessential genes, from the S. oneidensis whole genome knockout collection using a redox dye oxidation assay. Confirmation of electron uptake using electrochemical testing allowed us to identify five genes from S. oneidensis that are indispensable for electron uptake from a cathode. Knockout of each gene eliminates extracellular electron uptake, yet in four of the five cases produces no significant defect in electron donation to an anode. This result highlights both distinct electron uptake components and an electronic connection between aerobic and anaerobic electron transport chains that allow electrons from the reversible EET machinery to be coupled to different respiratory processes in S. oneidensis. Homologs to these genes across many different genera suggesting that electron uptake by EET coupled to respiration could be widespread. These gene discoveries provide a foundation for: studying this phenotype in exotic metal-oxidizing microbes, genetic optimization of electron uptake in S. oneidensis; and genetically engineering electron uptake into a highly tractable host like E. coli to complement recent advances in synthetic CO 2 fixation 15 .

Enas Taha Sayed, Mohammad Ali Abdelkareem, Khaled Obaideen et al.

Carbon Resources Conversion • 2021

Living organisms' energy conversion is considered as an essential and sustainable green energy source and future bio-hybrid technologies. Recently, plants were used after harvesting as biomass in bio-fermentation as an energy source. In bio-electrochemical systems, microorganisms work with plants to generate electricity, hydrogen, or methane. This work discusses the simultaneous pollutant removal and electricity generation in plant-based bio-electrochemical systems (P-BES). Factors affecting the P-BES performance and the removal efficiencies of the different organic and inorganic pollutants were illustrated. Furthermore, the plant-based bioelectrochemical systems' role in achieving the sustainable development goals (SDGs) was discussed. The SDGs contribution of plant-based bioelectrochemical systems were presented and discussed to evaluate such systems' ability to achieve the three pillars of sustainable development, i.e., economic, environmental, and social.

Yongfei Liu, Jianming Liu, Jinglei Nie et al.

Chinese Science Bulletin (Chinese Version) • 2023

Global warming and climate change, mainly caused by the emission of carbon dioxide, is becoming a serious problem, and it is imperative to develop efficient capture and utilization technologies for carbon dioxide and its derivatives one-carbon (C1) compounds. The use of CO 2 and other C1 compounds, such as formate, methanol and formaldehyde, for biomanufacturing of industrial chemicals is of great importance in the transition from a fossil-dependent economy to a green and sustainable bioeconomy. This review article mainly focuses on the biosynthesis of chemicals with the use of C1 compounds in the context of synthetic biology and discusses the challenges as well as potential solutions in this field. First, we briefly highlight the development of synthetic biology and its relation to biomanufacturing as well as the introduction of low-carbon biosynthesis concept, which includes low-carbon feedstocks, low-carbon bioproduction process and low-carbon industrial chain. With a focus on C1 feedstocks, we then summarize the latest research advances in enhancing the carbon fixation efficiency of autotrophic microorganisms, empowering heterotrophs such as Escherichia coli and yeast with carbon fixation capabilities, and assembling cell-free machineries in biomanufacturing. Furthermore, we present a comparison of 10 natural and artificial CO 2 -fixation pathways, including their energy requirements and enzyme numbers in the corresponding pathway, which highlights the unique advantages of our recently developed integrated chemoenzymatic CO 2 to amino-acid pathway (ICE-CAP) to turn CO 2 into amino acids in a system without requirements for ATP/NAD(P)H and in only several steps. In the second part, we discuss the challenges faced in the chemical biosynthesis using C1 substrates, including the demand of high amounts of energy and reducing powers in carbon fixation pathways, low efficiency, low thermodynamic and kinetic driving forces of the pathway and the large gap between the practical needs of industrial applications and the currently limited capacity to use C1 compounds. As a promising solution, we presented the strategy to capture low-energy CO 2 using the high-energy C1 compound methanol or formaldehyde in ICE-CAP to increase the energy utilization efficiencies. Furthermore, the low thermodynamic driving force in carbon-fixation pathways can be overcome by combining biocompatible chemistry (non-enzymatic) with enzymatic transformations. From the perspective of industrial applications, we illustrate the feasibilities of performing mixotrophic fermentation to enhancing the key parameters in terms of titer, yield and productivity in C1 utilization process for producing chemicals. Furthermore, we pay special attention to the key intermediate formaldehyde, which as an energy-intensive C1 synthon is of high interest for biosynthesis, in C1 fixation and emphasize its pivotal role in the conversion of inorganic carbon to organic carbon and carbon-chain elongation. Different pathways and routes are summarized that involve formaldehyde as an intermediate or a starting point for biosynthesis. The toxicity of formaldehyde in principle can be overcome through adaptive laboratory evolution, enzyme engineering, compartmentalization of formaldehyde utilization and other means. Formaldehyde can be readily produced from methanol, formate, CO and CO 2 . As one of the power sources in producing formaldehyde, we introduce a concept of bioelectrochemically converting biogas (CO 2 and CH 4 ) into formaldehyde. In the third part, we take 1,3-propanediol (PDO) as an example to illustrate our efforts to produce this important chemical from C1 compounds. Finally, we discuss the need and challenges to move from the proof of concept (“0 to 1”) in fundamental research to the industrial application (“1 to 100”), as well as the key scientific and technical is

Longzhu Q. Shen, Giuseppe Amatulli, Tushar Sethi et al.

Scientific Data • 2020

Nitrogen (N) and Phosphorus (P) are essential nutritional elements for life processes in water bodies. However, in excessive quantities, they may represent a significant source of aquatic pollution. Eutrophication has become a widespread issue rising from a chemical nutrient imbalance and is largely attributed to anthropogenic activities. In view of this phenomenon, we present a new geo-dataset to estimate and map the concentrations of N and P in their various chemical forms at a spatial resolution of 30 arc-second (∼1 km) for the conterminous US. The models were built using Random Forest (RF), a machine learning algorithm that regressed the seasonally measured N and P concentrations collected at 62,495 stations across the US streams for the period of 1994-2018 onto a set of 47 in-house built environmental variables that are available at a near-global extent. The seasonal models were validated through internal and external validation procedures and the predictive powers measured by Pearson Coefficients reached approximately 0.66 on average.

Jamie Gomez, John Baca, Fernando H. Garzón

International Journal of Hydrogen Energy • 2019

Yi Mao, Yaqian Zhao, Sarah Cotterill

Water • 2023

Electrocoagulation (EC) has gained increasing attention as an effective and environmentally friendly technique for purifying water and wastewater. This review provides a comprehensive analysis of the recent literature on EC and identifies new trends and potentials for further research. Initially, the nature of EC and its operating parameters are discussed, while the research trends are analyzed using the Scopus database and VOSviewer software. From 1977 to 2022, 2691 research articles and review papers on EC for water/wastewater treatment were published, with the number of publications increasing from 2 in 1977 to 293 in 2022. In the past five years, most studies focused on treatment performance and the mechanism of EC systems. However, recent emphasis has been placed on combining EC with other treatment processes and addressing emerging pollutants. The innovative applications of EC are highlighted, including the removal of microplastics and per/polyfluoroalkyl substances, the power supply of EC via microbial fuel cells (MFCs) and electro-wetlands (EWs), and the application of power management systems in EC. The review concludes with suggestions for further research to enhance the technology and expand its scope of applications.

Furquan Nadeem, S. M. Suhail Hussain, Prashant Kumar Tiwari et al.

IEEE Access • 2018

It is an exciting time for power systems as there are many ground-breaking changes happening simultaneously. There is a global consensus in increasing the share of renewable energy-based generation in the overall mix, transitioning to a more environmental-friendly transportation with electric vehicles as well as liberalizing the electricity markets, much to the distaste of traditional utility companies. All of these changes are against the status quo and introduce new paradigms in the way the power systems operate. The generation penetrates distribution networks, renewables introduce intermittency, and liberalized markets need more competitive operation with the existing assets. All of these challenges require using some sort of storage device to develop viable power system operation solutions. There are different types of storage systems with different costs, operation characteristics, and potential applications. Understanding these is vital for the future design of power systems whether it be for short-term transient operation or long-term generation planning. In this paper, the state-of-the-art storage systems and their characteristics are thoroughly reviewed along with the cutting edge research prototypes. Based on their architectures, capacities, and operation characteristics, the potential application fields are identified. Finally, the research fields that are related to energy storage systems are studied with their impacts on the future of power systems.

Aishwarya Rani, Seth W. Snyder, Hyunook Kim et al.

npj Clean Water • 2022

Abstract The energy-consuming and carbon-intensive wastewater treatment plants could become significant energy producers and recycled organic and metallic material generators, thereby contributing to broad sustainable development goals, the circular economy, and the water-energy-sanitation-food-carbon nexus. This review provides an overview of the waste(water)-based energy-extracting technologies, their engineering performance, techno-economic feasibility, and environmental benefits. Here, we propose four crucial strategies to achieve net-zero carbon along with energy sufficiency in the water sector, including (1) improvement in process energy efficiency; (2) maximizing on-site renewable capacities and biogas upgrading; (3) harvesting energy from treated effluent; (4) a new paradigm for decentralized water-energy supply units.

Ulysse Brémond, Aude Bertrandias, Jean‐Philippe Steyer et al.

Journal of Cleaner Production • 2020

Qilin Yu, Yaobin Zhang

Nature Communications • 2019

Membrane fouling is a considerable challenge for the stable operation of anaerobic membrane-based bioreactors. Membrane used as a cathode is a common measure to retard fouling growth in anaerobic electrochemical membrane bioreactors (AnEMBR), which; however, cannot avoid the fouling growth. Here we report a strategy using the membrane as an anode to resist membrane fouling in an AnEMBR. Although aggravating in the initial stage, the fouling on the anode membrane is gradually alleviated by the anode oxidation with enriching exoelectrogens to finally achieve a dynamic equilibrium between fouling growth and decomposition to maintain the operation stable. A mesh-like biofilter layer composed of cells with less extracellular polymeric substance (EPS) is formed on the membrane surface to lower the trans-membrane pressure and promote the interception of the anode membrane. The membrane has high electron storage and transfer capacities to accelerate the oxidation of the intercepted fouling materials, especially, the redundant EPSs of the biofilter layer.

Paniz Izadi, Eileen Hao Yu

Joule • 2020

Min‐Soo Kim, Shuwei Li, Da Seul Kong et al.

SSRN Electronic Journal • 2022

Yuanyao Ye, Huu Hao Ngo, Wenshan Guo et al.

Bioresource Technology • 2019

Sanjeet Mehariya, Rahul Kumar Goswami, Pradeep Verma et al.

Energies • 2021

The increasing world population generates huge amounts of wastewater as well as large energy demand. Additionally, fossil fuel’s combustion for energy production causes the emission of greenhouse gases (GHG) and other pollutants. Therefore, there is a strong need to find alternative green approaches for wastewater treatment and energy production. Microalgae biorefineries could represent an effective strategy to mitigate the above problems. Microalgae biorefineries are a sustainable alternative to conventional wastewater treatment processes, as they potentially allow wastewater to be treated at lower costs and with lower energy consumption. Furthermore, they provide an effective means to recover valuable compounds for biofuel production or other applications. This review focuses on the current scenario and future prospects of microalgae biorefineries aimed at combining wastewater treatment with biofuel production. First, the different microalgal cultivation systems are examined, and their main characteristics and limitations are discussed. Then, the technologies available for converting the biomass produced during wastewater treatment into biofuel are critically analyzed. Finally, current challenges and research directions for biofuel production and wastewater treatment through this approach are outlined.

A K M Khabirul Islam, Psm Dunlop, Neil Hewitt et al.

Clean Technologies • 2021

Billions of litres of wastewater are produced daily from domestic and industrial areas, and whilst wastewater is often perceived as a problem, it has the potential to be viewed as a rich source for resources and energy. Wastewater contains between four and five times more energy than is required to treat it, and is a potential source of bio-hydrogen—a clean energy vector, a feedstock chemical and a fuel, widely recognised to have a role in the decarbonisation of the future energy system. This paper investigates sustainable, low-energy intensive routes for hydrogen production from wastewater, critically analysing five technologies, namely photo-fermentation, dark fermentation, photocatalysis, microbial photo electrochemical processes and microbial electrolysis cells (MECs). The paper compares key parameters influencing H2 production yield, such as pH, temperature and reactor design, summarises the state of the art in each area, and highlights the scale-up technical challenges. In addition to H2 production, these processes can be used for partial wastewater remediation, providing at least 45% reduction in chemical oxygen demand (COD), and are suitable for integration into existing wastewater treatment plants. Key advancements in lab-based research are included, highlighting the potential for each technology to contribute to the development of clean energy. Whilst there have been efforts to scale dark fermentation, electro and photo chemical technologies are still at the early stages of development (Technology Readiness Levels below 4); therefore, pilot plants and demonstrators sited at wastewater treatment facilities are needed to assess commercial viability. As such, a multidisciplinary approach is needed to overcome the current barriers to implementation, integrating expertise in engineering, chemistry and microbiology with the commercial experience of both water and energy sectors. The review concludes by highlighting MECs as a promising technology, due to excellent system modularity, good hydrogen yield (3.6–7.9 L/L/d from synthetic wastewater) and the potential to remove up to 80% COD from influent streams.

C. W. Marshall, Daniel E. Ross, Kim M. Handley et al.

Scientific Reports • 2017

Microbial electrosynthesis is a renewable energy and chemical production platform that relies on microbial cells to capture electrons from a cathode and fix carbon. Yet despite the promise of this technology, the metabolic capacity of the microbes that inhabit the electrode surface and catalyze electron transfer in these systems remains largely unknown. We assembled thirteen draft genomes from a microbial electrosynthesis system producing primarily acetate from carbon dioxide, and their transcriptional activity was mapped to genomes from cells on the electrode surface and in the supernatant. This allowed us to create a metabolic model of the predominant community members belonging to Acetobacterium, Sulfurospirillum, and Desulfovibrio. According to the model, the Acetobacterium was the primary carbon fixer, and a keystone member of the community. Transcripts of soluble hydrogenases and ferredoxins from Acetobacterium and hydrogenases, formate dehydrogenase, and cytochromes of Desulfovibrio were found in high abundance near the electrode surface. Cytochrome c oxidases of facultative members of the community were highly expressed in the supernatant despite completely sealed reactors and constant flushing with anaerobic gases. These molecular discoveries and metabolic modeling now serve as a foundation for future examination and development of electrosynthetic microbial communities.

Neha Chauhan, Toru Maekawa, D. Sakthi Kumar

Journal of materials research/Pratt's guide to venture capital sources • 2017

Sanath Kondaveeti, Ibrahim M. Abu-Reesh, Gunda Mohanakrishna et al.

Frontiers in Energy Research • 2020

Changes in the environment due to multiple factors such as combustion of fossil fuels, heating, transportation, deforestation, etc. had led to more greenhouse gases in atmosphere that eventually lead to rise in global temperatures. Carbon dioxide (CO2) is the major factor for rapid rise in global temperature. One of the best encouraging technological advances to address global warming is to transform CO2 into value-added commodities that offer a win-win strategy. In this regard, intensive research has been pursued around the world for development of feasible systems in product recovery or product synthesis from CO2 rich industrial emissions. We envision that biological CO2 reduction or conversion process can be beneficial for developing carbon neutral technologies. The integration of CO2 emitting industrial technologies with CO2 converting biological systems can be helpful in achieving sustainable value-added products with no or minimal loss of energy and materials which is assuring for improved economics. The CO2 converting bioprocesses can be directly integrated with the processes emitting high amount of CO2. This symbiotic integration can make the whole process carbon neutral. Herein, this review highlights an insight on research activities of biological CO2 mitigation using photo catalysts (algae and photo bacteria), anaerobic biocatalyst (bacteria), gas fermentation and enzymatic catalyst. Perspectives and challenges of these technologies have been discussed.

Grzegorz Pasternak, John Greenman, Ioannis Ieropoulos

Sensors and Actuators B Chemical • 2017

Standard Biological Oxygen Demand (BOD) analysis requires 5 days to complete. To date, microbial fuel cell biosensors used as an alternative method for BOD assessment requires external apparatus, which limits their use for on-line monitoring in remote, off-grid locations. In this study, a self-powered, floating biosensor was developed for online water quality monitoring. This approach eliminated the need for external apparatus and maintenance that would otherwise be required by other techniques. The biosensor was able to detect urine in freshwater and turn ON a visual and sound cues (85 dB). The energy needed to operate the biosensor was produced by the system itself with the use of electroactive microorganisms, inside microbial fuel cells. The Chemical Oxygen Demand (COD) was used as a fast method of biosensor validation. When urine concentration exceeded the lower threshold, corresponding to a COD concentration of 57.7 ± 4.8 mgO 2 L -1 , the biosensor turned the alarm ON. The shortest observed actuation time, required to switch ON the alarm was 61 min, when the urine concentration was 149.7 ± 1.7 mgO 2 L -1 . Once the sensor was switched ON, the signal was emitted until the urine organic load decreased to 15.3 ± 1.9 mgO 2 L -1 . When ON, the microbial fuel cell sensor produced a maximum power of 4.3 mW. When switched OFF, the biosensor produced 25.4 μW. The frequency of the signal was proportional to the concentration of urine. The observed frequencies varied between 0.01 and 0.59 Hz. This approach allowed to correlate and quantitatively detect the presence of water contamination, based on signal frequency. The sensor was operating autonomously for 5 months. This is the first report of a self-powered, autonomous device, developed for online water quality monitoring.

Kelsey K. Sakimoto, Nikolay Kornienko, Peidong Yang

Accounts of Chemical Research • 2017

Photosynthetic biohybrid systems (PBSs) combine the strengths of inorganic materials and biological catalysts by exploiting semiconductor broadband light absorption to capture solar energy and subsequently transform it into valuable CO2-derived chemicals by taking advantage of the metabolic pathways in living organisms. In this work, we first traverse through a brief history of recent PBSs, demonstrating the modularity and diversity of possible architectures to rival and, in many cases, surpass the performance of chemistry or biology alone before envisioning the future of these hybrid systems, opportunities for improvement, and its role in sustainable living here on earth and beyond.

Michael J. McAnulty, Venkata Giridhar Poosarla, Kyoung‐Yeol Kim et al.

Nature Communications • 2017

Given our vast methane reserves and the difficulty in transporting methane without substantial leaks, the conversion of methane directly into electricity would be beneficial. Microbial fuel cells harness electrical power from a wide variety of substrates through biological means; however, the greenhouse gas methane has not been used with much success previously as a substrate in microbial fuel cells to generate electrical current. Here we construct a synthetic consortium consisting of: (i) an engineered archaeal strain to produce methyl-coenzyme M reductase from unculturable anaerobic methanotrophs for capturing methane and secreting acetate; (ii) micro-organisms from methane-acclimated sludge (including Paracoccus denitrificans) to facilitate electron transfer by providing electron shuttles (confirmed by replacing the sludge with humic acids), and (iii) Geobacter sulfurreducens to produce electrons from acetate, to create a microbial fuel cell that converts methane directly into significant electrical current. Notably, this methane microbial fuel cell operates at high Coulombic efficiency.

Sizhu Ren, Ziyuan Wang, Muhammad Bilal et al.

International Journal of Biological Macromolecules • 2020

Man Chen, Xiaofang Zhou, Yu‐Qing Yu et al.

Environment International • 2019

N 2 O (Nitrous oxide, a booster oxidant in rockets) has attracted increasing interest as a means of enhancing energy production, and it can be produced by nitrate (NO 3 - ) reduction in NO 3 - -loading wastewater. However, conventional denitrification processes are often limited by the lack of bioavailable electron donors. In this study, we innovatively propose a self-photosensitized nonphototrophic Thiobacillus denitrificans (T. denitrificans-CdS) that is capable of NO 3 - reduction and N 2 O production driven by light. The system converted >72.1 ± 1.1% of the NO 3 - -N input to N 2 ON, and the ratio of N 2 O-N in gaseous products was >96.4 ± 0.4%. The relative transcript abundance of the genes encoding the denitrifying proteins in T. denitrificans-CdS after irradiation was significantly upregulated. The photoexcited electrons acted as the dominant electron sources for NO 3 - reduction by T. denitrificans-CdS. This study provides the first proof of concept for sustainable and low-cost autotrophic denitrification to generate N 2 O driven by light. The findings also have strong implications for sustainable environmental management because the sunlight-triggered denitrification reaction driven by nonphototrophic microorganisms may widely occur in nature, particularly in a semiconductive mineral-enriched aqueous environment.