Griffin Chure, Zofii A. Kaczmarek, Rob Phillips

bioRxiv (Cold Spring Harbor Laboratory) • 2019

ABSTRACT The intimate relationship between the environment and cellular growth rate has remained a major topic of inquiry in bacterial physiology for over a century. Now, as it becomes possible to understand how the growth rate dictates the wholesale reorganization of the intracellular molecular composition, we can interrogate the biophysical principles underlying this adaptive response. Regulation of gene expression drives this adaptation, with changes in growth rate tied to the activation or repression of genes covering enormous swaths of the genome. Here, we dissect how physiological perturbations alter the expression of a circuit which has been extensively characterized in a single physiological state. Given a complete thermodynamic model, we map changes in physiology directly to the biophysical parameters which define the expression. Controlling the growth rate via modulating the available carbon source or growth temperature, we measure the level of gene expression from a LacI-regulated promoter where the LacI copy number is directly measured in each condition, permitting parameter-free prediction of the expression level. The transcriptional output of this circuit is remarkably robust, with expression of the repressor being largely insensitive to the growth rate. The predicted gene expression quantitatively captures the observations under different carbon conditions, indicating that the bio-physical parameters are indifferent to the physiology. Interestingly, temperature controls the expression level in ways that are inconsistent with the prediction, revealing temperature-dependent effects that challenge current models. This work exposes the strengths and weaknesses of thermodynamic models in fluctuating environments, posing novel challenges and utility in studying physiological adaptation. Significance Cells adapt to changing environmental conditions by repressing or activating gene expression from enormous fractions of their genome, drastically changing the molecular composition of the cell. This requires the concerted adaptation of transcription factors to the environmental signals, leading to binding or releasing of their cognate sequences. Here, we dissect a well characterized genetic circuit in a number of physiological states, make predictions of the response, and measure how the copy number of a regulator and its gene target are affected. We find the parameters defining the regulators behavior are remarkably robust to changes in the nutrient availability, but are susceptible to temperature changes. We quantitatively explore these two effects and discuss how they challenge current models of transcriptional regulation.

Jordi Pla-Mauri, Ricard Solé

bioRxiv (Cold Spring Harbor Laboratory) • 2025

Living systems have evolved cognitive complexity to reduce environmental uncertainty, enabling them to predict and prepare for future conditions. Anticipation, distinct from simple prediction, involves active adaptation before an event occurs and is a key feature of both neural and non-neural biological agents. Recent work by Steven Frank proposed a minimal anticipatory mechanism based on the moving average convergence-divergence principle from financial markets. Here, we implement this principle using synthetic biology to design and evaluate minimal genetic circuits capable of anticipating environmental trends. Through deterministic and stochastic analyses, we demonstrate that these motifs achieve robust anticipatory responses under a wide range of conditions. Our findings suggest that simple genetic circuits could be naturally exploited by cells to prepare for future events, providing a foundation for engineering predictive biological systems.

Gan Lin

International Journal of Biology and Life Sciences • 2023

Microbial metabolic engineering is a new bioengineering technology, which can improve the yield of compounds, optimize energy utilization and solve various problems faced by human beings by changing the genetic information, metabolic pathway and metabolic flux of microorganisms. Protein is the main undertaker of life activities, and its metabolic process involves complex biochemical reactions and cell regulation mechanisms. Protein metabolism plays an important role and application in microbial metabolic engineering. The purpose of this paper is to explore the metabolic effects of protein for microbial metabolic engineering, so as to deeply understand the metabolic characteristics and regulation mechanism of microorganisms. Microbial metabolic engineering has important applications in improving the yield of compounds, optimizing energy utilization, environmental treatment and medicine. The research and application of protein metabolism can provide more in-depth theoretical basis and technical support for microbial metabolism engineering, thus promoting the development and utilization of microbial resources.

Daniele Cecconet, Fabrizio Sabba, Matyas Devecseri et al.

Preprints.org • 2019

Groundwater contamination is an ever-growing environmental issue, that has attracted much and undiminished attention for the past half century. Groundwater contamination originates from anthropogenic (e.g. hydrocarbons), natural compounds (e.g. nitrate and arsenic), or both; to tackle these contaminants different technologies have been tested during the years. Recently, bioelectrochemical systems (BESs) have emerged as a potential treatment for groundwater contamination, with in situ applications reported, that showed promising results. Nitrate and hydrocarbons (toluene, phenanthrene, benzene, BTEX and light PAHs) have been successfully removed, due to the interaction of microbial metabolism with poised electrodes, other than physical migration due to the electric field generated in BES. The selection of proper BESs relies on several factors and problems such as complexity of the groundwater, scale-up and energy requirements that need to be taken into account. Modelling efforts could help predict case scenarios and choose an ideal design and approach to solve these issues. In this review, we critically analyze in situ BES applications for groundwater remediation, focusing in particular on the different setups proposed, and we identify and discuss the existing research gaps in the field.

Andreea Stoica, Karthikeyan Rengasamy, Tahina Onina Ranaivoarisoa et al.

Preprints.org • 2025

Miniaturization of measurement systems offers several advantages, including reduced sample and reagent volumes, improved control over experimental conditions, and the ability to multiplex complementary measurement modalities, thereby enabling new types of studies in microbial electrochemistry. We present a scalable glass-based microfluidic bioelectrochemical cell (µ-BEC) platform for multiplexed investigations of microbial extracellular electron uptake (EEU). The platform integrates eight independently addressable three-electrode cells in a 2×4 array, with transparent working electrodes that support simultaneous electrochemical analysis and optical imaging. Using Rhodopseudomonas palustris TIE-1 as a model phototroph, we measured EEU activity under light-dark cycling. Microfluidic flow was used to selectively remove planktonic cells, enabling isolation of the electron uptake signal associated with surface attached cells. These results demonstrate the µ-BEC as a robust and adaptable platform for probing microbial electron transfer, with broad potential for high-throughput and multimodal studies.

Adam Krieger, Jiahao Zhang, Xiaoxia Nina Lin

bioRxiv (Cold Spring Harbor Laboratory) • 2020

Abstract Engineering of synthetic microbial communities is emerging as a powerful new paradigm for performing various industrially, medically, and environmentally important processes. To reach the fullest potential, however, this approach requires further development in many aspects, a key one being regulating the community composition. Here we leverage well established mechanisms in ecology which govern the relative abundance of multi-species ecosystems and develop a new tool for programming the composition of synthetic microbial communities. Using a simple model system consisting of two microorganisms Escherichia coli and Pseudomonas putida , which occupy different but partially overlapping thermal niches, we demonstrate that temperature regulation can be used to enable coexistence and program the community composition. We first investigate a constant temperature regime and show that different temperatures lead to different community compositions. Next, we invent a new cycling temperature regime and show that it can dynamically tune the microbial community, achieving a wide range of compositions depending on parameters that are readily manipulatable. Our work provides conclusive proof of concept that temperature regulation is a versatile and powerful tool capable of programming compositions of synthetic microbial communities.

Sophie J. Walton, Samuel E. Clamons, Richard M. Murray

bioRxiv (Cold Spring Harbor Laboratory) • 2020

Designing genetic circuits to control the behaviors of microbial populations is an ongoing challenge in synthetic biology. Here we analyze circuits which implement dosage control by controlling levels of a global signal in a microbial population in face of varying cell density, growth rate, and environmental dilution. We utilize the Lux quorum sensing system to implement dosage control circuits, and we analyze the dynamics of circuits using both simplified analytical analysis and in silico simulations. We demonstrate that strong negative feedback through inhibiting LuxI synthase expression along with AiiA degradase activity results in circuits with fast response times and robustness to cell density and dilution rate. We find that degradase activity yields robustness to variations in population density for large population sizes, while negative feedback to synthase production decreases sensitivity to dilution rates.

C. Retief, S. Kumar, K. Tepper et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2024

Abstract Background Insects, such as Black Soldier Flies ( Hermetia illucens ), are increasingly used as sustainable animal feed ingredients that can be reared on plentiful organic substrates such as agricultural residues and pre-consumer food waste. Genetically engineering insects to heterologously express feed additive enzymes has the potential to generate more value from organic waste, while improving livestock health and productivity. Phytases are widely used feed additive enzymes that hydrolyse the phosphate groups from the myo-inositol backbone of phytic acid, a phosphate rich antinutrient compound that monogastric animals cannot efficiently digest. Dietary phytase supplementation improves absorption of phosphorous, proteins, and cationic nutrients, while mitigating the negative environmental effects of phytic acid rich excreta. Results We evaluated the potential of using insects to biomanufacture microbial feed additive enzymes by engineering the model insect, Drosophila melanogaster , to express phytases. One histidine acid phytase, three beta propellor phytases, three purple acid phosphatases, and one PTP-like phytase were selected for screening in D. melanogaster . Transgenic flies expressing the AppA histidine acid phytase from E. coli had 27.82 FTU/g of phytase activity, which exceeds the 0.5-1.0 FTU/g required in animal feed. Maximum activity from AppA phytase expressed by D. melanogaster was observed at pH 5 and 55 °C, however, more than 50% of phytase activity was present at 25 °C and pH 2. Here we demonstrate that insects may be suitable hosts for the heterologous expression of a microbial phytase enzyme with applications for improving animal feed nutrition and organic waste valorisation.

Ahmad A. Mannan, Declan G. Bates

bioRxiv (Cold Spring Harbor Laboratory) • 2020

Abstract Bacteria can be harnessed to synthesise high-value chemicals. A promising strategy for increasing productivity uses inducible control systems to switch metabolism from growth to chemical synthesis once a large population of cell factories are generated. However, use of expensive chemical inducers limits scalability of this approach for biotechnological applications. Switching using cheap nutrients is an appealing alternative, but their tightly regulated uptake and consumption again limits scalability. Here, using mathematical models of fatty acid uptake in E. coli as an exemplary case study, we unravel how the cell’s native regulation and program of induction can be engineered to minimise inducer usage. We show that integrating positive feedback loops into the circuitry creates an irreversible metabolic switch, which, requiring only temporary induction, drastically reduces inducer usage. Our proposed switch should be widely applicable, irrespective of the product of interest, and brings closer the realization of scalable and sustainable microbial chemical production.

Philip Bittihn, Andriy Didovyk, Lev S. Tsimring et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2019

Abstract Rapid advances in cellular engineering 1,2 have positioned synthetic biology to address therapeutic 3,4 and industrial 5 problems, but a significant obstacle is the myriad of unanticipated cellular responses in heterogeneous environments such as the gut 6,7 , solid tumors 8,9 , bioreactors 10 or soil 11 . Complex interactions between the environment and cells often arise through non-uniform nutrient availability, which can generate bidirectional coupling as cells both adjust to and modify their local environment through different growth phenotypes across a colony. 12,13 While spatial sensing 14 and gene expression patterns 15–17 have been explored under homogeneous conditions, the mutual interaction between gene circuits, growth phenotype, and the environment remains a challenge for synthetic biology. Here, we design gene circuits which sense and control spatiotemporal phenotype patterns in a model system of heterogeneous microcolonies containing both growing and dormant bacteria. We implement pattern control by coupling different downstream modules to a tunable sensor module that leverages E. coli⁉s stress response and is activated upon growth arrest. One is an actuator module that slows growth and thereby creates an environmental negative feedback via nutrient diffusion. We build a computational model of this system to understand the interplay between gene regulation, population dynamics, and chemical transport, which predicts oscillations in both growth and gene expression. Experimentally, this circuit indeed generates robust cycling between growth and dormancy in the interior of the colony. We also use the stress sensor to drive an inducible gating module that enables selective gene expression in non-dividing cells. The ‘stress-gated lysis circuit’ derived from this module radically alters the growth pattern through elimination of the dormant phenotype upon a chemical cue. Our results establish a strategy to leverage and control the presence of distinct microbial growth phenotypes for synthetic biology applications in complex environments.

Cecilia Trivellin, Lisbeth Olsson, Peter Rugbjerg

bioRxiv (Cold Spring Harbor Laboratory) • 2021

Abstract Stable cell performance in a fluctuating environment is essential for sustainable bioproduction and synthetic cell functionality; however, microbial robustness is rarely quantified. Here, we describe a high-throughput strategy for quantifying robustness of multiple cellular functions and strains in a perturbation space. We evaluated quantifications theory on experimental data and concluded that the mean-normalized Fano factor allowed accurate, reliable, and standardized quantification. Our methodology applied to perturbations related to lignocellulosic bioethanol production showed that Saccharomyces cerevisiae Ethanol Red exhibited both higher and more robust growth rates than CEN.PK and PE-2, while a more robust product yield traded off for lower mean levels. The methodology validated that robustness is function-specific and characterized by positive and negative function-specific trade-offs. Systematic quantification of robustness to end-use perturbations will be important to analyze and construct robust strains with more predictable functions. Graphical Abstract

Philipp Gaspers, Christoph Bickmann, Christina Wallner et al.

Small • 2025

Abstract Engineered Living Materials (ELMs) combine synthetic biology with artificial materials to create biohybrid living systems capable of replicating, self‐repairing, and responding to external stimuli. Due to their self‐optimization abilities, these systems hold great potential for biotechnological applications. This study is a first step toward ELMs based on DNA hydrogels, focusing on the production of biohybrid materials using the exoelectrogenic bacterium Shewanella oneidensis. To equip the bacterium with the functionality needed for building DNA hydrogels, inducible cell surface anchors are developed, which can bind exogenous polymerase via the SpyCatcher/SpyTag (SC/ST) technology. The process parameters for in situ production of DNA hydrogels are established, enabling the development of these materials in the context of living bacteria for the first time. Using an extracellular nuclease‐deficient S. oneidensis strain, stable biohybrid biofilms are generated directly on the surface of bioelectrochemical systems, showing the current generation. Given the high programmability and functionalization potential of DNA hydrogels, it is believed that this study represents a significant step toward establishing dynamic biohybrid material systems that exhibit both conductivity and metabolic activity.

Satya Prakash, Adrian Racovita, Clenira Varela et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2022

Abstract Gene circuits enable cells to make decisions by controlling the expression of genes in reaction to specific environmental factors 1 . These circuits can be designed to encode logical operations 2–7 , but implementation of more complex algorithms has proved more challenging. Directed evolution optimizes gene circuits 8 without the need for design knowledge 9 , but adjusting multiple genes and conditions 10 in genotype searches poses challenges 11 . Here we show a multicellular sensor system, AdaptoCells, in Escherichia coli, that can evolve complex behavior through an accelerated adaptation to chemical environments. AdaptoCells recognize chemical patterns and act as a decision-making system. Using an iterative improvement method, we demonstrate that the AdaptoCells can evolve to achieve mastery in the game of tic-tac-toe, demonstrating an unprecedented level of complexity for engineered living cells. We provide an effective and straightforward way to encode complexity in gene circuits, allowing for fast adaptation in response to dynamic environments and leading to optimal decisions.

Aaron Yip, Owen D. McArthur, Kalista C. Ho et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2024

Abstract Microplastics are contaminants of global concern that pose risks to ecosystems and human health. Focusing on PET plastics, we present a proof-of-concept for reduction of microplastic pollution: in situ engineering of bacteria in wastewater to degrade PET. Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some isolates could degrade about 40% of a 0.25 mm thick PET film within four days at 50 °C. We then demonstrate partial degradation of post-consumer PET over 5-7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET plastics in situ .

Tapio Lehtinen, Henri Virtanen, Suvi Santala et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2018

Abstract Background Microbial biosynthesis of alkanes is considered a promising method for the sustainable production of drop-in fuels and chemicals. Carbon dioxide would be an ideal carbon source for these production systems, but efficient production of long carbon chains from CO 2 is difficult to achieve in a single organism. A potential solution is to employ acetogenic bacteria for the reduction of CO 2 to acetate, and engineer a second organism to convert the acetate into long-chain hydrocarbons. Results In this study, we demonstrate alkane production from CO 2 by a system combining the acetogen Acetobacterium woodii and a non-native alkane producer Acinetobacter baylyi ADP1 engineered for alkane production. Nine synthetic two-step alkane biosynthesis pathways consisting of different aldehyde- and alkane-producing enzymes were combinatorically constructed and expressed in A. baylyi. The aldehyde-producing enzymes studied were AAR from Synechococcus elongatus, Acr1 from A. baylyi, and Ramo, a putative dehydrogenase, from Nevskia ramosa. The alkane-producing enzymes were ADOs from S. elongatus and Nostoc punctiforme, and CER1 from Arabidopsis thaliana. The performance of the pathways was evaluated with a twin-layer biosensor, which allowed the monitoring of both the intermediate, fatty aldehyde, as well as the alkane production. The highest alkane production, as indicated by the biosensor, was achieved with a pathway consisting of AAR and ADO from S. elongatus. The performance of this pathway was further improved by balancing the relative expression levels of the enzymes in order to limit the accumulation of the intermediate fatty aldehyde. Finally, the acetogen A. woodii was used to produce acetate from CO 2 and H 2 , and the acetate was used for alkane production by the engineered A. baylyi, thereby leading to the net production of long-chain alkanes from CO 2 . Conclusions A modular system for the production of drop-in liquid fuels from CO 2 was demonstrated. Among the studied synthetic pathways, the combination of ADO and AAR from S. elongatus was found to be the most efficient in heterologous alkane production in A. baylyi. Furthermore, limiting the accumulation of the fatty aldehyde intermediate was found to be beneficial for the alkane production.

Cabelkova I*

Food Science & Nutrition Technology • 2024

Genetically modified (GM) foods have been at the center of global debate, resulting in diverse public perceptions and regulatory responses. Proponents argue that GM foods are crucial for addressing food security and climate change challenges, highlighting their potential to increase crop yields, enhance nutritional quality, and reduce the environmental impact of agriculture. However, skepticism persists, driven by concerns about potential health risks, environmental effects, and ethical implications. Despite a scientific consensus affirming the safety of GM foods, factors such as cultural values, media influence, and distrust in regulatory authorities have significantly shaped public attitudes, particularly in regions like Europe, Asia, and parts of Africa where skepticism is higher. In contrast, the United States and Latin America show relatively greater acceptance, influenced by economic benefits and trust in scientific institutions like the FDA and EPA. This paper examines the key factors influencing public perception of GM foods, including knowledge gaps, media misinformation, ethical concerns, and regulatory trust. It also explores regional differences in attitudes towards GM foods and provides strategies to bridge the divide in public acceptance. Effective communication, increased transparency in regulatory processes, and inclusive engagement with the public are critical in building trust and fostering a more balanced understanding of GM technology. Addressing these challenges is essential for aligning public perceptions with scientific evidence and promoting informed decision-making about the role of GM foods in the global food system.

Christopher Rodgers

The Regulation of Genetically Modified Organisms: Comparative Approaches • 2010

Abstract This chapter assesses the role for environmental liability in the context of the GMOs, with emphasis on the provisions of the Community Environmental Liability Directive. It commences with discussion of the role of liability regimes more generally (adopting Coasean analysis) and compares and contrasts the Environmental Liability Directive with the Lugano Convention. The application of the Environmental Liability Directive is then considered in detail, with particular attention devoted to: the definition of environmental damage, the basis of liability (whether strict or grounded upon fault), the use of the administrative liability model, and risk allocation and insurance. The chapter concludes that the Community regime has serious limitations. Not least, its territorial application is largely restricted to the Natura 2000 network of protected wildlife sites, where GM crop cultivation is in practice unlikely to occur.

Jason Lai

Matrix Science Medica • 2024

This paper examines the ethics, economic effects, and global marketing and communication styles of genetically modified organisms (GMOs). While GMOs have sparked controversial debates since their 1994 introduction, evidence from this paper suggests that they offer significant environmental, health, and economic benefits. Analysis in this paper also shows that effective communication and marketing strategies for GMOs are vital to bridge the gap between scientific consensus and false public perception, ensuring that GMOs are used ethically and sustainably.

Duncan French

The Regulation of Genetically Modified Organisms: Comparative Approaches • 2010

Abstract Much has been written on the legal implications of the international regulation of GMOs. This chapter does not reproduce this discussion, but rather considers how general rules of international law, together with more general trends in related legal and policy fields, are likely to prove increasingly apposite in the ongoing debate over how to manage and govern GM activity. In particular, it considers two specific issues: first, the role of treaty interpretation in promoting synergies and reconciling apparently conflicting primary rules; and, secondly, the utility of the concept of sustainable development in determining a balanced framework for the inclusion of socio-economic considerations within GM decision-making processes, as permitted under the Cartagena Protocol. The chapter concludes that an approach which concentrates solely on the regulatory detail will invariably ignore the importance of general international law in regulating such an issue.

Fikremarkos Merso Birhanu

The Regulation of Genetically Modified Organisms: Comparative Approaches • 2010

Abstract Modern biotechnology has promised much for agriculture, and these promises are certainly attractive in the case of Africa. Importantly, a number of countries in the continent continue to grapple with food insecurity and starvation. But it remains controversial whether modern biotechnology, in its current state, can overcome these unique challenges. For reasons such as biosafety and fear of loss of export markets, Africa has remained largely ambivalent towards GM crops, and the regulatory regimes governing biosafety in several countries largely restrict their development. While recognizing some of the hurdles which modern biotechnology must clear before it can deliver its promises, this chapter argues that the continent stands to benefit from promoting the development and safe use of GM crops. It further argues that African countries should invest heavily in research and development, with a view to owning the technology and ensuring relevance to their circumstances. This should be the guiding objective of biosafety regulation in Africa.

Michelle Marvier

Oxford Scholarship Online • 2017

This chapter explores ongoing debates surrounding the environmental safety of genetically modified (GM) crops. Systematic review and meta-analysis provide convincing evidence that Bt crops are safer than insecticides for non-target invertebrate species, such as honeybees and ladybird beetles. In addition, widespread adoption of Bt crops has resulted in reduced use of insecticides and other benefits for the environment. Despite such evidence, there remains a substantial opinion gap between the general public and scientists regarding the safety of GM crops. While systematic review and meta-analysis can help to correct for bias in environmental and conservation science, the oversimplification of environmental issues into blackand- white dichotomies such as pro- versus anti-GM crops can stymie the adoption of genuine solutions.

Adnan Aftab, Silvia Salgar-Chaparro, Quan Xie et al.

• 2024

Today our energy sectors are focusing on the marathon of CO2 cut and coherently require progress in energy transition schemes to meet the UN climate change challenge and achieve a zero-emission target. Among these schemes, radioactive disposal, CO2, NH3, and H2 geological storage are promising options for fixing anthropogenic waste, greenhouse gases and storing green energy in the depleted oil/gas reservoirs, deep saline aquifers, and salt caverns. Consequently, this could be achieved through rigorous research and development (R&D) projects involving laboratory-scale experiments. Despite the ubiquity of microorganisms in various environments, their potential impact on laboratory studies in fields outside of the biological sciences is not well established. In particular, their presence in research related to new energy technologies, such as hydrogen storage, poses a significant risk to experimental integrity. Microorganisms can consume hydrogen and other substances, leading to potentially misleading results. This oversight can have profound implications, especially when studying geological formations where microbial contamination might alter the properties and behaviours of reservoir rocks. Thus, it is crucial to incorporate sterile controls in experiments to accurately assess the influence of independent variables and to discern the specific effects of microbial presence. The effect of ultraviolet (UV), autoclave, oven heating, ethanol 75%, ethanol 95%, and gamma irradiation for cleaning microorganisms in the sand were investigated Interestingly, our experimental results revealed that gamma irradiation and autoclave heating are the most vibrant options for extinguishing microorganisms from the surface of the rock and saying no to the risk of experimental error in future work reflecting geological storage applications.

Yang Ding, Martin Komainda, Kyle Mason-Jones et al.

• 2022

<p>A diverse range of soil microorganisms accumulate energy to secure their future needs under resource fluctuation or deficiency. Microbial intracellular storage can substantially mediate the stress of resource variability across time, thereby supporting growth and reproduction. Microbial storage is well known in industrial applications and under pure culture conditions, yet few studies address its importance in the soil. To evaluate how widespread microbial energy storage is in soil, we quantified the contents of two intracellular storage compounds, polyhydroxybutyrate (PHB) and triacylglycerides (TAGs), from seven permanent grasslands in Germany differing in field management (grazing/mowing and fertilizing) and soil types. In winter 2021, soil was collected from two depths, 5-10 cm called topsoil, and >30 cm called subsoil, to capture different soil carbon inputs from grass roots. The storage compound contents were determined by gas chromatography–mass spectrometry (GC-MS). We hypothesized that the carbon input controls the storage compound levels. From topsoil to subsoil, as root carbon inputs (estimated from the fresh root weight) drop with depth, microbial storage levels follow suit. Dissolved organic carbon (DOC) was measured to qualify carbon availability to microorganisms, and microbial biomass carbon (MBC) was to assess microbial biomass. The root weight in the topsoil was 20-50 times higher than in the subsoil, while MBC and DOC contents were 3-4 and 1.5-2.5 times higher, respectively. Storage levels and MBC decreased with depth, and showed a positive correlation with DOC. This experiment allowed us to quantify intracellular storage occurrence in soils and to understand how its distribution related to root carbon input. These results point out that microbial intracellular carbon storage might accumulate according to the available carbon level (root carbon inputs) for microorganisms. Thus, this carbon plays a pivotal role for microbial ecology of soils as it prepares the microbial cells to survive throughout the winter when less carbon is provided by plants.</p>

Qi Luo, Zhongming Li, Yongxin Li et al.

Research Square • 2025

Abstract For millennia, cement has been regarded as inert structural material. Here, we challenge this long-standing perception by transforming cement into a “living” energy device, pioneering the first microbial cement supercapacitor. This biohybrid system achieves 178.7 Wh/kg energy density and 8.3 kW/kg power density, surpassing state-of-the-art cement-based capacitors and some lithium-ion capacitors. By integrating electroactive microorganisms into cement, we established a functional charge storage network that leverages extracellular electron transfer to enable dynamic redox-active energy storage. This system exhibits cycling stability, retaining 88% of its capacitance after 5,000 cycles. Even after microbial inactivation, residual conductive networks and redox-active biofilms sustain charge storage. Moreover, we introduce a reactivation strategy, wherein an embedded microfluidic network periodically supplies nutrients to restore microbial activity, enabling up to 18% capacitance recovery and sustaining long-term charge transfer efficiency. Our findings establish a new paradigm for bio-integrated, cement-based energy materials, paving the way for energy-autonomous infrastructure.

Ehsan Akbari, Abbas Zare Ghaleh Seyyedi

• 2023

Although the capability of multifunctional grid-tied inverters (MFGTI) to compensate the voltage-based power quality is limited, more attention has been paid to their ability to improve power quality for effective use of renewable energy sources (RES) and grid resources even in poor power quality conditions. This paper proposes a MFGTI to compensate all power quality issues based on voltage, current and harmonic distortions caused by load and grid as a promising solution in microgrids. In this scheme, the proposed MFGTI can be connected to the grid in series or parallel via bidirectional switches to react to the disturbances occurring across the grid. The necessary compensation of current and voltage are mathematically extracted according to the grid and load situation to regulate the voltage. Also, in the proposed method, compensation strategies, control scheme and transients in the MFGTI are presented and in addition to compensate the balanced and unbalanced grid voltage disturbances, grid current is also compensated and harmonic distortions of PCC voltage and current is also reduced as much as possible under the allowable value. The simulation results to confirm the proposed method including the compensation of unbalanced voltage sag/swell, harmonics and interruption are performed in Simulink/MATLAB environment.

Ahmad Alyan, Jeyraj Selvaraj, Nasrudin Abd Rahim

Preprints.org • 2025

Energy storage systems (ESS) have recently emerged as a prevalent solution for mitigating the variability of intermittent renewable energy sources. One of the primary challenges associated with ESS is their cost. This paper aims to explore methods for reducing the size of ESS without compromising performance. Data was collected from a grid-tied 2MW PV unit in Malaysia over several days, as many variables exhibit significant fluctuations from hour to hour due to solar irradiation. Python code was developed to analyze the effects of varying ESS sizes on power grid smoothing. Both high-power density devices and high-energy density devices were tested, and the impact of changing output period durations was investigated. The output should remain stable for no less than five minutes, which is the minimum acceptable timeframe. SIMULINK was utilized to simulate the recommended ESS size, employing a vanadium redox battery (VRB) as the high-energy density device and supercapacitors (SC) as the high-power density device.

NANDINI V

Research Square • 2024

Abstract The concept of the electric vehicle and its adaptability paved its way almost by itself as the IC (internal combustion engines) were gradually replaced due to the depletion of fossil fuels and the emission of greenhouse gases. The electric vehicle operates solely on electricity and requires a power source to do so. In view of the increasing shift to electric vehicles, the source from which the electricity is generated should also be considered from time to time. In the current trends, renewable and hybrid energy options are more focused on charging infrastructure for electric vehicles to achieve zero emission process. This paper elaborates on the role of renewable energy in residential electric vehicle charging infrastructure. The grid-connected PV systems in the residential units are used during the day for charging the vehicles at level 2 AC. The maximum power generated by the PV source so installed is extracted by implementing the Incremental Conductance (INC) algorithm. The maximum power is obtained by using 9-level multilevel inverter which enables residential EVSE infrastructure. In addition, the implementation of bidirectional functions such as Vehicle to Grid (V2G), Vehicle to Home (V2H) and Vehicle to Vehicle (V2V) is also discussed.

Olukorede Tijani Adenuga, Senthil Krishnamurthy

Preprints.org • 2023

The requirement for integration of power plants due to the cyclical rise in electrical energy consumption is due to fluctuating load demand with the current grid systems. This integration necessitates effective allocating loads to the power plants for a minimum grid-tied transmission line cost while meeting network constraints. In this paper, we formulate an optimisation problem of minimising the total operational cost of all committed plants transmitted to the grid while meeting network constraints and ensuring economic power dispatch (EPD) and energy management system co-optimization. The developed Particle Swarm Optimization (PSO) method resolve the optimisation problem using piecewise quadratic function to describe the operational cost of the generation units, and the B coefficient approach is employed to estimate the transmission losses. Intelligent adjustments are made to the acceleration coefficients, and a brand-new algorithm is suggested for distributing the initial power values to the generation units. The developed economic power dispatch strategy successfully demonstrated an imperative cost reduction with connected load of 850MW, 1263MW and 2630MW power demand are contrasted with previous PSO application cost values, maximum yearly cost savings of (0.55%, 91.87), (46.55%, 3.78), (73.86%, 89.10) respectively, and significant environmental-benefit. The proposed co-optimisation approach can enhance a significant self-consumption ratio compared to the baseline method.

Ahmad Alyan, Nasrudin Abd Rahim, Jeyraj Selvaraj

Preprints.org • 2025

Power smoothing for renewable energy resources is receiving increasing attention. One widely used resource is the grid-tied photovoltaic (PV) system. Solar energy production typically follows a Gaussian bell curve, with peaks at midday; however, climate varia-tions can significantly alter this pattern. This paper aims to smooth the power supplied to the grid by the PV system. The proposed controller manages the charge and discharge processes of the Energy Storage System (ESS) to ensure a smooth Gaussian bell curve out-put. It adjusts the parameters of this curve to closely match the generated energy, absorb-ing or supplying fluctuations to maintain the desired profile. This system aims also to provide accurate predictions of the power that should be supplied to the grid by the PV system, based on the capabilities of the ESS and the overall system performance. Although experimental results were not included in this analysis, the system was implemented in SIMULINK using real-world data. It utilizes a hybrid ESS comprising a Vanadium Redox Battery (VRB) and Supercapacitors (SC). The design and operation of the controller, in-cluding curve tuning and ESS charge‒discharge management, are detailed. The simula-tion results demonstrate excellent performance and are thoroughly discussed.

Stuart Licht

ECS Transactions • 2011

STEP, Solar Thermal Electrochemical Production, provides an advance in solar energy conversion efficiency through the use of the full solar spectrum to generate energy rich chemicals. The process captures solar energy with conversion efficiency greater than that of photovoltaics, and rather than electricity, produces the chemical products needed by society. This original process is derived and demonstrated for the solar production of energetically rich chemicals, including iron, and hydrogen fuel without the evolution of carbon dioxide, and to proactively convert and capture anthropogenic CO2 generated in burning fossil fuels. The STEP process distinguishes radiation that is energy sufficient to drive photovoltaic charge transfer, and applies all excess energy to heat and decrease the energy of endothermic electrolysis reactions. Energy sufficient, visible, sunlight drives photovoltaic charge transfer, and available heat, infrared sunlight, and excess visible sunlight, heats, and decreases the energy of, an electrolysis reaction.

E. L. Wolf

Oxford Scholarship Online • 2018

The Sun’s spectrum on Earth is modified by the atmosphere, and is harvested either by generating heat for direct use or for running heat engines, or by quantum absorption in solar cells, to be discussed later. Focusing of sunlight requires tracking of the Sun and is defeated on cloudy days. Heat engines have efficiency limits similar to the Carnot cycle limit. The steam turbine follows the Rankine cycle and is well developed in technology, optimally using a re-heat cycle of higher efficiency. Having learned quite a bit about how the Sun’s energy is created, and how that process might be reproduced on Earth, we turn now to methods for harvesting the energy from the Sun as a sustainable replacement for fossil fuel energy.

Yuxin Huo

2022 12th International Conference on Bioscience, Biochemistry and Bioinformatics • 2022

Since the industrial revolution, fossil fuels have been the main energy source of human activity. After few centuries of continuous use, the storage of fossil fuels has been declining and the cost are becoming increasingly higher in the coming decades. For these reasons, it is essential to research and develop new approaches of producing energy through harvesting renewable energies. This paper introduces a hypothetical concept that produces electrical energy from bio-redox flow cells which integrates energy conversion and storage system through combining the concepts of bio-photovoltaic cell, fuel cell, microbial fuel cell, and flow cell. The system is expected to be environmentally friendly and energy efficient. In addition, we expect that phenazine-1-carboxylic acid (PCA), the energy storage material of the bio-redox flow cell, can be biosynthesized by Pseudomonas aeruginosa. To be specific, the bio-redox flow cell charging process operates through the reduction of PCA and the oxidation of water, which is catalysed by chloroplast with the utilization of sunlight, producing reduced PCA and oxygen. The bio-redox flow cell discharge process operates through the electrochemical oxidation of reduced PCA and electrochemical reduction of oxygen, releasing electricity, PCA, and H2O.

Jiri Vanek, Marek Pekarek, Kristyna Jandova

Research Square • 2024

Abstract In this paper, we compare different photovoltaic systems with electrochemical battery storage of electricity for a selected family house in the Czech Republic in the Opava area and the option with the power plant direct selling energy to the grid or with the use of a distributor service called virtual battery. The work also includes an economic analysis and a calculation of the return on investment, considering the available energy products from energy suppliers in the Czech Republic.

Huang Huanhai

Materials Science: Materials Review • 2018

The potential crisis of energy and the deterioration of ecological environment make the world's cumbersomedevelopment of renewable energy including new energy, including solar energy. Traditional energy in the coal, oil andnatural gas are evolved from ancient fossils, it is collectively referred to as fossil fuels. As the world's energy needscontinue to increase, fossil fuels will also be depleted, it is necessary to fi nd a new energy to replace the traditionalenergy. Solar energy is a clean renewable energy with mineral energy incomparable superiority. Modern society shouldbe a conservation-oriented society, and social life should also be a life-saving energy. At the same time, Premier WenJiabao also proposed on June 30, 2005 and stressed the need to speed up the construction of a conservation-orientedsociety. And solar energy as an inexhaustible new environmentally friendly energy has become the world's energyresearch work in the world an important issue. Is the world in the economic situation to take a simpler, economical,environmentally friendly and reliable building heating and heating energy-saving measures. This paper summarizes thecurrent global energy status, indicating the importance of solar power and prospects. Details of the various solar powergeneration methods and their advantages, and made a comparison of this power generation parameters. At the sametime pointed out that the diffi culties faced by solar power and solutions, as well as China's solar power of the favorableconditions and diffi culties. The future of China's solar energy made a prospect.

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International Journal of Recent Technology and Engineering • 2019

A two-stage PV water-pumping system architecture is represented in this paper. In contrast with other alternatives available in the literature, the electronic drive does not exploit batteries to accomplish energy decoupling, neither large electrolytic capacitors in between stages. Although these two design decisions respectively minimize environmental impacts and increase the converter’s expected lifetime, they also bring about considerable control difficulties. More specifically, the DC link stiffness is reduced and thus large voltage oscillations may occur. In order to overcome this problem, a nonlinear controller interconnection between the individual compensator of each stage is created to account for the low capacitance. Simulations and experimental results demonstrate the effectiveness of the method in stabilizing the DC-link voltage under sudden solar irradiation changes. The final converter was deployed in a remote rural community in Guinea-Bissau for crop irrigation purposes. Despite the harsh conditions such as high temperatures and sea breeze, in situ results were satisfactory and validated the system robustness

Ghadeer Badran, Mahmoud Dhimish

Research Square • 2024

Abstract This paper presents the first comprehensive study of a groundbreaking Vertically Mounted Bifacial Photovoltaic (VBPV) system, marking a significant innovation in solar energy technology. The VBPV system, characterized by its vertical orientation and the use of high-efficiency Heterojunction (HJT) cells, introduces a novel concept diverging from traditional solar panel installations. Our empirical research, conducted over a full year at the University of York, UK, offers an inaugural assessment of this pioneering technology. The study reveals that the VBPV system significantly outperforms both a vertically mounted monofacial PV (VMPV) system and a conventional tilted monofacial PV (TMPV) system in energy output. Key findings include a daily power output increase of 7.12% and 10.12% over the VMPV system and an impressive 26.91% and 22.88% enhancement over the TMPV system during early morning and late afternoon hours, respectively. Seasonal analysis shows average power gains of 11.42% in spring, 8.13% in summer, 10.94% in autumn, and 12.45% in winter compared to the VMPV system. Against the TMPV system, these gains are even more substantial, peaking at 24.52% in winter. These results underscore the VBPV system's exceptional efficiency in harnessing solar energy across varied environmental conditions, establishing it as a promising and sustainable solution in solar energy technology.

Gerasimos Kanellos, Asimina Tremouli, Petros Tsakiridis et al.

Research Square • 2023

Abstract The solar energy sector has grown rapidly in the past decades, addressing the issues of energy security and climate change. Many photovoltaic panels that were installed during this technological revolution, have accumulated as waste and even more are nearing their End-of-Life (EoL). Based on circular economy, a new hydrometallurgical process has been proposed for the management of the EoL PVs. This results in a chemical extract containing 0.7 % w/w Ag, along with various other metals. This study investigates the cell power generation and the kinetics of the silver recovery, along with the parasitic removal of other heavy metals, both from synthetic and the real chemical extract in the cathode of a Microbial Fuel Cell (MFC). The results indicated that silver was completely recovered from the synthetic and the real chemical extract, with a rate of ~82 μmol/h and ~32 μmol/h, respectively. The difference is attributed to the simultaneous reduction of other heavy metals in amorphous compounds, hindering the silver reduction kinetics and leading to a gradual electrode passivation. Nevertheless, silver can be 100% retrieved from the chemical extract, with a purity of 68-96% w/w (average 86% w/w at the end of the batch cycle), in crystal (face center cube) structure, containing minor metal impurities.

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Journal of Applied Fluid Mechanics • 2023

Wind energy is an alternative future energy to fossil fuels since it is abundant and green energy. As a result, high performance unique design is proposed that has a diffuser augmented wind turbine including intake funnel with guide vanes, natural fan, straight flow section, exit splitter with air openings and end flange. This proposed design is called as Integrated omni-directional Intake funnel, Natural fan, Straight diffuser, Splitter and Flange (I2NS2F) Design. To construct this I2NS2F configuration, four distinct wind turbines were developed: a) bare wind turbine, b) wind turbine diffuser design with single rotor turbine, c) bend diffuser, intake funnel, natural fan, splitter and flange and d) I2NS2F design. The proposed designs are numerically studied using MATLAB Simulink and Ansys Fluent. These designs are optimized by Random Search Optimization with Supervisory Control and Data Acquisition technique to evaluate the wind velocity and the performance is comparatively estimated. From this analysis, I2NS2F design achieves 53m/s of wind velocity at turbine region for 5.5m/s inlet wind and it could be considered as highest wind velocity than other three designs. It is evidently proved and concluded that proposed I2NS2F design augments natural wind, resulting in greater green power generation.

Lucas Touw, Pablo Jaen Sola, Erkan Oterkus

Wind • 2023

Rotor and stator support structures of significant size and mass are required to withstand the considerable loads that direct-drive wind turbine electrical generators face to maintain an air-gap clearance that is open and stable. With the increase of scale, reducing the weight and environmental impact of these support structures is believed to be one of the key components to unlocking the true potential of direct-drive generators. An investigation on the electrical generator rotor structure of the IEA 15 MW offshore reference wind turbine was conducted. An integrated approach that considered the environmental impact, including the manufacturing energy usage and CO2 footprint, as well as the financial repercussions of structural parameter modifications as they are optimised was followed, making use of distinct commercial pieces of software. The rotor structure was parametrically optimised, and its operating loading conditions were evaluated at various size scales. The study determined that the effect of thermal loading is significant, which forces the designer to augment the mass to comply with the imposed structural requirements. The ensuing life-cycle assessment showed an increase in the environmental impact due to the consideration of this particular load, whose effect in structural deflection and stress has been typically underestimated.

Shaig Hamzaliyev, Eva P.S. Eibl, Gylfi Páll Hersir et al.

• 2022

<p>A geyser is a multiphase geothermal feature that exhibits frequent, jetting<br>eruptions of hot water and non-condensable gases such as CO2. In Iceland it<br>was noted that Strokkur geyser erupts at regular intervals. Following single<br>eruptions the typical waiting time is for example 3.7 ± 0.9 min. However, we<br>noted that single eruptions are sometimes followed by an up to 7 min long<br>gap and are the first ones to investigate this in the context of the weather at<br>Strokkur.<br>A local broadband seismic network at Strokkur geyser, Iceland recorded more<br>than 300000 eruptions during 2017-2018 and 2020-2021. The hourly weather<br>data was acquired from the Hjardarland meteorological station at a few kilome-<br>ters distance from Strokkur maintained by the Icelandic Meteorological Office.<br>First we calculate the waiting time after eruptions and to make it comparable<br>with the hourly weather data we calculate hourly means. First we used a sim-<br>ple pearson correlation to calculate the correlation in different time windows.<br>As the time window increased the correlation between the waiting time and<br>wind speed increased. No substantial increase in the correlation coefficients was<br>visible for window lengths of more than 8 hours. So we chose an 8 hour long<br>time window for the further analysis. We compare the averaged waiting time<br>after eruptions, with wind speed, temperature, air pressure and humidity. To<br>understand the relation more deeply, we plot each weather parameter vs. the<br>waiting time average and fit linear and quadratic functions to the data. We<br>find a strong correlation with the wind speed and minor anticorrelation with<br>temperature and humidity. After calculating residuals the results indicate that<br>there is a quadratic relation between the waiting time and wind speed. This<br>highlights the sensitivity of the pool geyser with respect to environmental factors<br>interfering with the heat balance of the system.</p>