J. Nduko, S. Taguchi

Frontiers in Bioengineering and Biotechnology • 2021

Polyhydroxyalkanoates (PHAs) are naturally occurring biopolymers produced by microorganisms. PHAs have become attractive research biomaterials in the past few decades owing to their extensive potential industrial applications, especially as sustainable alternatives to the fossil fuel feedstock-derived products such as plastics. Among the biopolymers are the bioplastics and oligomers produced from the fermentation of renewable plant biomass. Bioplastics are intracellularly accumulated by microorganisms as carbon and energy reserves. The bioplastics, however, can also be produced through a biochemistry process that combines fermentative secretory production of monomers and/or oligomers and chemical synthesis to generate a repertoire of biopolymers. PHAs are particularly biodegradable and biocompatible, making them a part of today’s commercial polymer industry. Their physicochemical properties that are similar to those of petrochemical-based plastics render them potential renewable plastic replacements. The design of efficient tractable processes using renewable biomass holds key to enhance their usage and adoption. In 2008, a lactate-polymerizing enzyme was developed to create new category of polyester, lactic acid (LA)–based polymer and related polymers. This review aims to introduce different strategies including metabolic and enzyme engineering to produce LA-based biopolymers and related oligomers that can act as precursors for catalytic synthesis of polylactic acid. As the cost of PHA production is prohibitive, the review emphasizes attempts to use the inexpensive plant biomass as substrates for LA-based polymer and oligomer production. Future prospects and challenges in LA-based polymer and oligomer production are also highlighted.

Jiyuan Lee, C. Ng, P. K. Lo et al.

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects • 2019

ABSTRACT This study designed to enhance the energy recovery by the microbial fuel cell (MFC) fed with palm oil mill effluent. The maximum voltage output of 267.1 ± 5.5 mV and power density of 344.3 ± 8.6 mW/m2 were obtained with MFC operated at sludge retention times of 70 days, 1.25 gCOD/L/day organic loading rate, 7 g/L of activated carbon with an average particle size of 60.232 µm. It also had the relatively lower internal resistance and biogas yield at 156 Ω and 111.5 ± 11.4 mL/gCOD, respectively. It also had the highest coulombic efficiency (CE) at 3.06 ± 0.61% and the COD removal efficiency amounted to 91.90 ± 0.44%.

Kechrist Obileke, N. Nwokolo, G. Makaka et al.

Energy & Environment • 2020

The authors reviewed the future prospects and previous studies on anaerobic digestion technology for biogas production and highlight the solutions to problems relating to construction and maintenance of biogas digesters, which can now be accessed in a single paper. It is the aim of the review to provide insight into the use, process and application of anaerobic digestion as an appropriate technology for biogas production from peer reviewed literature. Recent studies have shown that the microbial communities and metabolic pathways involves in anaerobic digestion are influenced by temperature. Their metabolic activities increase significantly with increase in temperature. Therefore, the findings of the review reveal that temperature is a major parameter for biogas production due to its influence on metabolic activities involved in anaerobic digestion. Hence, there is the need for insulation as well as external heating to maintain temperature stability and to avoid temperature fluctuations. More also, the anaerobic digestion technology for production of biogas is a viable option that can supplement as well as reduce the usage of non-renewable energy sources such as fossil fuel. The detailed information addressed in this study would increase biogas energy mix as well as mitigating climate change. Therefore, the study recommends the use of biogas as a clean energy for the purpose of power generation, cooking and heating.

V. Gadhamshetty, Namita Shrestha, J. Kilduff

Journal of Professional Issues in Engineering Education and Practice • 2016

AbstractThe National Academy of Engineering has called for the reinvention of engineering education by exposing students to the iterative process of designing, predicting performance, building, and testing; incorporating research into engineering education; and introducing interdisciplinary learning in the undergraduate environment. Here we describe a novel effort to integrate an undergraduate research project into the problem-based design environment of a second-year introduction to engineering design course at Rensselaer Polytechnic Institute, providing a design and research experience early in the curriculum. The project-based environment allows students to learn technical communication (technical writing and oral presentations) and teamwork (including conflict management and team coordination) in parallel. Approximately 600 sophomores from different science, technology, engineering, and mathematics (STEM) disciplines take the course, working in multidisciplinary teams to address a complex challenge fa...

Virendra K. Singh, Akanksha Saxena, Asha Gupta et al.

International Journal of Renewable Energy Technology • 2017

Energy crisis in the world is increasing on a yearly basis due to depletion of reserved fossil fuels as well as continued increase in the prices. There is an urgent need to identify an alternate fuel or a renewable source for energy production. Hence, microbial fuel cells (MFCs) can play an important major role in producing bioelectricity using various organic and biodegradable waste. The traditional MFCs consisted of anode and cathode compartments. MFCs are of two types single chambered and double chambered. Micro-organisms actively use organic substrate for their metabolism, and the bioelectricity generated. Apart from the bioelectricity production, MFCs has many applications like in wastewater treatment, in biosensor, in bio-hydrogen production, in bio-methane production etc. Besides the advantages of this technology, MFCs have some limitations such as low voltage, power and current density. To overcome these limitations, the different components of MFC such as electrodes and proton exchange membrane modified to explore the other possible practical options. Besides that, this research update describes the improvement and advancement of MFCs with their advantageous and futuristic application with different parameters affecting the bioelectricity production.

Muhammad Zia Ur Rahman, R. Liaquat, M. Rizwan et al.

Fractal and Fractional • 2022

The focus on renewable energy is increasing globally to lessen reliance on conventional sources and fossil fuels. For renewable energy systems to work at their best and produce the desired results, precise feedback control is required. Microbial electrochemical cells (MEC) are a relatively new technology for renewable energy. In this study, we design and implement a model-based robust controller for a continuous MEC reactor. We compare its performance with those of traditional methods involving a proportional integral derivative (PID), H-infinity (H∞) controller and PID controller tuned by intelligent genetic algorithms. Recently, a dynamic model of a MEC continuous reactor was proposed, which describes the complex dynamics of MEC through a set of nonlinear differential equations. Until now, no model-based control approaches for MEC have been proposed. For optimal and robust output control of a continuous-reactor MEC system, we linearize the model to state a linear time-invariant (LTI) state-space representation at the nominal operating point. The LTI model is used to design four different types of controllers. The designed controllers and systems are simulated, and their performances are evaluated and compared for various operating conditions. Our findings show that a structured linear fractional transformation (LFT)-based H∞ control approach is much better than the other approaches against various performance parameters. The study provides numerous possibilities for control applications of continuous MEC reactor processes.

M. Azuma, Yoshihiro Ojima

Current Topics in Biochemical Engineering • 2018

In this chapter, we focus on microbial fuel cells (MFCs) that convert the energy from organic matters into electrical energy using microorganisms. MFCs are greatly expected to be used as a relatively low-cost and safe device for generating renewable energy using waste biomass as a raw material. At present, however, it has not reached the desired practical application because of the low-power generation; hence, improvements on fuel cell efficiency, such as electrode materials, are still being examined. Here, we focus on the microorganisms that can be used as catalysts and play a central role in improving the efficiency of the fuel cells. Several kinds of microbial catalysts are used in MFCs. For example, Shewanella oneidensis has been well studied, and as known, since S. oneidensis transports the electrons generated within the cell to the surface layer, it does not require a mediator to pass the electrons from the cells to the electrode. Furthermore, Escherichia coli and Saccharomyces cerevisiae , a model organism for MFCs, are also used. The improvements of such microbial catalysts have also been proceeding actively. Here, we elaborated on the principle of MFCs as well as the current situation and latest research on the catalyst development.

Lisa Marie Schmitz, Nicolai Kreitli, Lisa Obermaier et al.

• 2024

Meeting a surging demand for superior micronutrient-rich protein sources and finding production practices that are less detrimental to the climate will be critical challenges of the 21st century. New technologies are needed to decouple food production from land use. Our group previously proposed a two-stage Power-to-Protein technology to produce microbial protein from renewable electric power and CO2. Two stages were operated in series: (1) Clostridium ljungdahlii in Stage A to utilize H2 to reduce CO2 into acetate; and (2) Saccharomyces cerevisiae in Stage B to utilize O2 and produce microbial protein from acetate. Renewable energy would power water electrolysis to produce H2 and O2. A disadvantage of C. ljungdahlii in Stage A is the need to continuously feed vitamins to sustain growth and acid production. Changing to the more robust thermophilic acetogen Thermoanaerobacter kivui avoids providing any vitamins. Additionally, S. cerevisiae produces folate when grown with acetate as a sole carbon source under aerobic conditions. A total folate concentration of 6.7 mg per 100 g biomass with an average biomass concentration of 3 g L-1 in Stage B is achieved. The developed Power-to-Vitamin system enables folate production from renewable power and CO2 with zero or negative net-carbon emissions.

Chun Fu, A. A. Shah, Mohammed Alissa et al.

Journal of Applied Entomology • 2024

Insect gut microbes represent a rich source of enzymes and metabolic pathways that can be harnessed to advance renewable energy production. This review explores the potential of insect gut microbiota in the context of biomass degradation and biofuel production. Insects, particularly wood‐feeding species like termites and beetles, harbour complex microbial communities in their guts that efficiently break down lignocellulosic materials into simple sugars. These sugars can then be fermented into biofuels such as ethanol and methane. Recent research has focused on identifying key microbial species and enzymes involved in this process, as well as on engineering these microbes to enhance their efficiency and substrate specificity. Additionally, the ecological roles of these microbes in insect digestion and their potential for biotechnological applications beyond biofuel production are discussed. Overall, understanding and harnessing insect gut microbes holds great promise for advancing sustainable and renewable energy solutions.

Mohammad Faisal Umar, M. Rafatullah, Syed Zaghum Abbas et al.

International Journal of Environmental Research and Public Health • 2021

Anthropogenic activities are largely responsible for the vast amounts of pollutants such as polycyclic aromatic hydrocarbons, cyanides, phenols, metal derivatives, sulphides, and other chemicals in wastewater. The excess benzene, toluene and xylene (BTX) can cause severe toxicity to living organisms in wastewater. A novel approach to mitigate this problem is the benthic microbial fuel cell (BMFC) setup to produce renewable energy and bio-remediate wastewater aromatic hydrocarbons. Several mechanisms of electrogens have been utilized for the bioremediation of BTX through BMFCs. In the future, BMFCs may be significant for chemical and petrochemical industry wastewater treatment. The distinct factors are considered to evaluate the performance of BMFCs, such as pollutant removal efficiency, power density, and current density, which are discussed by using operating parameters such as, pH, temperature and internal resistance. To further upgrade the BMFC technology, this review summarizes prototype electrode materials, the bioremediation of BTX, and their applications.

D. Lima, Li Li, G. Appleby

Energies • 2024

The global trend towards sustainable development has included the implementation of renewable energy recovery technologies in municipal wastewater treatment plants (WWTPs). WWTPs are energy-intensive consumers with high operational costs and often are dependent from the electricity supplied by the main grid. In this context, the integration of renewable energy recovery technologies into WWTPs emerges as an environment-friendly strategy that enhances energy efficiency, sustainability and reduces energy operating costs. Renewable energy recovery technologies, such as anaerobic digestion, microbial fuel cells, and sludge gasification, can offer multiple benefits for a WWTP. Anaerobic digestion is the most widely adopted technology due to its efficiency in treating sewage sludge and its ability to generate biogas—a valuable renewable energy source. The use of biogas can offset the energy demands of the wastewater treatment process, potentially leading to energy self-sufficiency for the WWTP and a reduction in reliance from the electricity supply from the main grid. Similarly, microbial fuel cells harness the electrochemical activity of bacteria to produce electricity directly from wastewater, presenting a promising alternative for low-energy processes for sustainable power generation. Gasification of sewage sludge is a promising technology for managing municipal sewage sludge, offering key advantages, especially by generating a renewable energy production (sludge is converted into syngas), which further decreases the sludge volume and operating costs with sludge management, helps to eliminate odour associated with sewage sludge, and effectively destroys the pathogens. Adoption of renewable energy sources in WWTPs can be a great alternative to overcome issues of high operating costs and high dependency of electricity from the main grid, but their successful integration requires addressing challenges such as technological maturity, economic feasibility, and regulatory frameworks. This study aims to comprehensively explore the significance of different renewable energy technologies in municipal WWTPs, including site-specific and non-site-specific sources, evaluating their impact on sustainability, energy efficiency, and overall operational effectiveness. This review also highlights some studies in which different strategies were adopted to generate extra revenue and/or reduce operating costs. Through a comprehensive review of current practices and emerging technologies, this study underscores the transformative potential of these innovations in advancing low-emission wastewater management.

A. Worku, D. W. Ayele, Deva Brinda Deepak et al.

Advanced Energy and Sustainability Research • 2024

Currently, fossil fuels play a major role in meeting the world's energy demand. Fossil fuels, in contrast, threaten the planet's ecosystems and biological processes, contribute to global warming, and result in unfavorable climatic shifts. These energy sources are also finite and will eventually deplete. Thus, energy transition, which is the key from fossil fuels to renewable energy sources, is regarded as an essential course of action for decarbonizing the global economy and reducing the catastrophic and irreversible effects of climate change. Thereby using/consuming green hydrogen energy is a vital solution to meet the world's challenges. Subsequently, the pros and cons of several hydrogen generation methods, such as the conversion of fossil fuels, biomass, water electrolysis, microbial fermentation, and photocatalysis, are then compared and outlined in terms of their technologies, economies, consumption of energy, environmental aspects, and costs. Currently, the chemical industry uses green hydrogen (H2) primarily to produce green emerging fuels methanol and ammonia (NH3), which are regarded as alternate sources of energy. Finally, the current state of energy demands, recent developments in renewable energy sources, and the potential of hydrogen as a future fuel are outlined. Moreover, the discussion concludes with predicted opportunities and challenges.

Simon Jegan Porphy Jegathese, Mohammed Farid

Journal of Renewable Energy • 2014

<jats:p>Algae are believed to be a good source of renewable energy because of its rapid growth rate and its ability to be cultivated in waste water or waste land. Several companies and government agencies are making efforts to reduce capital cost and operating costs and make algae fuel production commercially viable. Algae are the fastest growing plant and theoretically have the potential to produce more oil or biomass per acre when compared to other crops and plants. However, the energy efficiency ratio and carbon and water footprint for algal based biofuels still need to be evaluated in order to fully understand the environmental impact of algal derived biofuels.</jats:p>

Carlos F. M. Coimbra

Journal of Renewable and Sustainable Energy • 2022

<jats:p> Renewable energy resourcing and forecasting are enabling technologies for low-cost integration of increasingly higher market penetration of low-carbon power generation into the grid. The “Best Practices in Renewable Energy Resourcing and Integration” Special Collection Issue in the Journal of Renewable and Sustainable Energy covers best practices in solar and wind forecasting for renewable energy integration and includes datasets for testing, development, and for the augmented reproducibility of methods and results. This Special Collection focuses on manuscripts containing methodologies that substantially advance the state-of-the-art in renewable resourcing and forecasting. </jats:p>

Subiyanto, Azah Mohamed, M. A. Hannan

Journal of Renewable Energy • 2013

<jats:p>Photovoltaic (PV) system is one of the promising renewable energy technologies. Although the energy conversion efficiency of the system is still low, but it has the advantage that the operating cost is free, very low maintenance and pollution-free. Maximum power point tracking (MPPT) is a significant part of PV systems. This paper presents a novel intelligent MPPT controller for PV systems. For the MPPT algorithm, an optimized fuzzy logic controller (FLC) using the Hopfield neural network is proposed. It utilizes an automatically tuned FLC membership function instead of the trial-and-error approach. The MPPT algorithm is implemented in a new variant of coupled inductor soft switching boost converter with high voltage gain to increase the converter output from the PV panel. The applied switching technique, which includes passive and active regenerative snubber circuits, reduces the insulated gate bipolar transistor switching losses. The proposed MPPT algorithm is implemented using the dSPACE DS1104 platform software on a DS1104 board controller. The prototype MPPT controller is tested using an agilent solar array simulator together with a 3 kW real PV panel. Experimental test results show that the proposed boost converter produces higher output voltages and gives better efficiency (90%) than the conventional boost converter with an RCD snubber, which gives 81% efficiency. The prototype MPPT controller is also found to be capable of tracking power from the 3 kW PV array about 2.4 times more than that without using the MPPT controller.</jats:p>

Marcelinus Christwardana, Satrio Kuntolaksono, Athanasia Amanda Septevani et al.

International Journal of Renewable Energy Development • 2024

<jats:p>Microbial fuel cells (MFCs) are an innovative method that generates sustainable electricity by exploiting the metabolic processes of microorganisms. The membrane that divides the anode and cathode chambers is an important component of MFCs. Commercially available membranes, such as Nafion, are both costly, not sustainable, and harmful to the environment. In this study, a low-cost alternative membrane for MFCs based on a starch-carrageenan blend (SCB-LCM) was synthesized. The SCB-LCM membrane was created by combining starch and carrageenan and demonstrated a high dehydration rate of 98.87 % over six hours. SEM analysis revealed a smooth surface morphology with no pores on the membrane surface. The performance of SCB-LCM membrane-based MFCs was evaluated and compared to that of other membranes, including Nafion 117 and Nafion 212. All membranes tested over 25 hours lost significant weight, with SCB-LCM losing the least. The maximum power density (MPD) of the SCB-LCM MFCs was 15.77 ± 4.34 mW/m2, indicating comparable performance to commercial membranes. Moreover, the cost-to-power ratio for MFCs employing SCB-LCM was the lowest (0.03 USD.m2/mW) when compared to other membranes, indicating that SCB-LCM might be a viable and cost-effective alternative to Nafion in MFCs. These SCB-LCM findings lay the groundwork for future research into low-cost and sustainable membrane for MFC technologies.  </jats:p>

Glenn Paula P Constantino, Justine Mae C. Dolot, Kristopher Ray Simbulan Pamintuan

International Journal of Renewable Energy Development • 2023

<jats:p>The prevalence of non-renewable energy has always been a problem for the environment that needs a long-term solution. Plant-Microbial Fuel Cells (PMFCs) are promising bioelectrochemical systems that can utilize plant rhizodeposition to generate clean electricity on-site, without harming the plants, paving the way for simultaneous agriculture and power generation. However, one of the biggest hurdles in large-scale PMFC application is the diffused nature of power generation without a clear path to consolidate or amplify the small power of individual cells. In this study, stacking configurations of 3D-printed PMFCs are investigated to determine the amplification potential of bioelectricity. The PMFCs designed in this study are made of 3D-printed electrodes, printed from 1.75 mm Proto-pasta (ProtoPlant, USA) conductive PLA filament, and a terracotta membrane acting as the separator. Six cells were constructed with the electrodes designed to tightly fit with the ceramic separator when assembled. An agriculturally important plant (S. Melongena) was utilized as the model plant for testing purposes. Stacking of cells in series had resulted in severe voltage loss while stacking of cells in parallel preserved the voltage and current of the cells. Cumulative stacking verified the increasing voltage losses as more cells are connected in series, while voltage and current were generally supported well as more cells were connected in parallel. Combination stacks were also investigated, but while 2 sets of 3 cells in parallel stacked in series generated proportionately larger power and power density compared to individual cells, the drop in current density suggests that pure parallel stacks are still more attractive for scaling up, at least for the proposed stake design in this study. The results of this study indicated that the scale up of PMFC technology is possible in field applications to continuously generate electricity while growing edible plants.</jats:p>

Ahmad Murtaza Ershad

Journal of Renewable Energy • 2017

<jats:p>Renewable energy resources could play a vital role in the sustainable economic, social, and environmental development of Afghanistan. Heavy reliance of rural households on firewood, rising costs of fossil fuels, outdoor and indoor air pollution, and climate change are some of the challenges that can be addressed by diversifying our power production fuel inputs and adopting renewable energy technologies. In order to deploy and scale up renewable energy technologies and improve access to sustainable energy, clear policies and targets and dedicated institutions are crucial. Fortunately, Afghan government with the support of international community is setting ambitious targets for the renewable energy sector and is encouraging national and international investors to take part in the generation, transmission, and distribution of renewable energy especially electricity through Power Purchase Agreements or very cheap land leases. Thus, the objectives of this report are (I) to review the existing institutions in the field of renewable energy, (II) to review renewable energy policies and targets in Afghanistan, and (III) to identify institutional and policy gaps and recommend solutions.</jats:p>

Atieh Zabihallahpoor, Mostafa Rahimnejad, Farid Talebnia

RSC Advances • 0

<p>SMFCs are a bioelectricity production technology for low power applications. Recent advances in SMFCs are investigated to enhance their performance. Power improvement and organic matter reduction in SMFCs enlarge their range of applications.</p>

Diane Pamela Entienza Palmero, Kristopher Ray Simbulan Pamintuan

International Journal of Renewable Energy Development • 2023

<jats:p>Plant-Microbial Fuel Cell (PMFC) is an emerging technology that converts plant waste into electrical energy through rhizodeposition, offering a renewable and sustainable source of energy. Deviating from the traditional PMFC configurations, additive manufacturing was utilized to create intricate and efficient designs using polymer-carbon composites. Concerning the agricultural sector, the effect of 3D-printed PMFCs on the growth and biomass distribution of Phaseolus lunatus and Ipomoea aquatica was determined. The experiment showed that electrostimulation promoted the average daily leaf number and plant height of both polarized plants, which were statistically proven to be greater than the control (α = 0.05), by energizing the flow of ions in the soil, boosting nutrient uptake and metabolism. It also stimulated the growth of roots, increasing the root dry mass of polarized plants by 155.44% and 66.30% for I. aquatica and P. Lunatus against their non-polarized counterpart. Due to the biofilm formation on the anode surface, the number of root nodules of the polarized P. lunatus was 51.30% higher than the control, while the protein content in the PMFC setup was 42.22% and 8.26% higher than the control for I. aquatica and P. lunatus, respectively. The voltage readings resemble the plants' average growth rate, and the polarization studies showed that the optimum external resistances in the I. aquatica- and P. lunatus-powered PMFC were 4.7 kΩ and 10 kΩ, respectively. Due to other prevailing pathways of organic carbon consumption, such as methanogenesis, the effect of polarization on the organic carbon content in soil is currently inconclusive and requires further study.</jats:p>

Yuanyuan Cao, Jianming Yao, Jun Li et al.

Journal of Renewable and Sustainable Energy • 2013

<jats:p>To reuse kitchen garbage for microbial oils, increase the liquid yield, and reduce the production cost, response surface methodology based on Box-Behnken design was employed to identify the optimum conditions for microbial oils production from kitchen garbage by the Geotrichum robustum G9 strain. Experimental results showed that the theoretical maximum lipid yield of 9.89 g/l was obtained with the following optimum conditions: time at 7.55 days, pH at 6.16, and temperature at 28 °C, when the lipid yield could reach 20 kg per ton of kitchen garbage. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 cultured by kitchen garbage was mainly composed of 16-carbon and 18-carbon fatty acids. Such compositional features were similar to plant oil, the widely used feedstock for biodiesel at present. Kitchen garbage could be considered as ideal substrate for the G. robustum G9 strain for biodiesel production. The utilization of kitchen garbage for microbial oils production could reduce cost as well as reduce pollution.</jats:p>

Muhamad Izzuddin Bin Zamli, M. H. Maziati Akmal, Farah B Ahmad et al.

International Journal of Renewable Energy Development • 2022

<jats:p>In this study, chitosan thin film derived from Aspergillus oryzae cell walls was fabricated and characterised. First, the chitosan from the fungal biomass was extracted (0.18 g/g) with 52.25% of degree of deacetylation obtained through Fourier transform infrared (FTIR) spectroscopy. Subsequently, several parameters of the chitosan thin film fabrication were optimised, including chitosan solution volume and drying temperature. Resultantly, the highest mechanical quality factor (3.22±0.012), the lowest dissipation factor (0.327±0.0003) and the best tensile strength (13.35±0.045 MPa) were obtained when pure chitosan was dissolved in 35 ml of 0.25 M formic acid and dried at 60 ˚C. In addition, the scanning electron microscopy (SEM) analysis presented a fine chitosan agglomerate distributed in the formic acid. The optimised fabricated, fungal-derived chitosan thin film was validated, recording a mechanical quality factor of 3.68 and dissipation factor of 0.248; both values were comparable to the synthetic polymer, polyvinylidene fluoride (PVDF) thin film. Thus, fungal-derived chitosan thin film can potentially be used as a piezoelectric material.</jats:p>

Samuel J. King, Ante Jerkovic, Louise J. Brown et al.

Microbial Biotechnology • 2022

<jats:title>Summary</jats:title><jats:p>Hydrogen is a clean alternative to fossil fuels. It has applications for electricity generation and transportation and is used for the manufacturing of ammonia and steel. However, today, H<jats:sub>2</jats:sub> is almost exclusively produced from coal and natural gas. As such, methods to produce H<jats:sub>2</jats:sub> that do not use fossil fuels need to be developed and adopted. The biological manufacturing of H<jats:sub>2</jats:sub> may be one promising solution as this process is clean and renewable. Hydrogen is produced biologically via enzymes called hydrogenases. There are three classes of hydrogenases namely [FeFe], [NiFe] and [Fe] hydrogenases. The [FeFe] hydrogenase HydA1 from the model unicellular algae <jats:italic>Chlamydomonas reinhardtii</jats:italic> has been studied extensively and belongs to the A1 subclass of [FeFe] hydrogenases that have the highest turnover frequencies amongst hydrogenases (21,000 ± 12,000 H<jats:sub>2</jats:sub> s<jats:sup>−1</jats:sup> for <jats:italic>Ca</jats:italic>HydA from <jats:italic>Clostridium acetobutyliticum</jats:italic>). Yet to date, limitations in <jats:italic>C. reinhardtii</jats:italic> H<jats:sub>2</jats:sub> production pathways have hampered commercial scale implementation, in part due to O<jats:sub>2</jats:sub> sensitivity of hydrogenases and competing metabolic pathways, resulting in low H<jats:sub>2</jats:sub> production efficiency. Here, we describe key processes in the biogenesis of HydA1 and H<jats:sub>2</jats:sub> production pathways in <jats:italic>C. reinhardtii</jats:italic>. We also summarize recent advancements of algal H<jats:sub>2</jats:sub> production using synthetic biology and describe valuable tools such as high‐throughput screening (HTS) assays to accelerate the process of engineering algae for commercial biological H<jats:sub>2</jats:sub> production.</jats:p>

Xinhui Wang, Hongyang Ren

Journal of Renewable and Sustainable Energy • 2014

<jats:p>Lipid accumulation in Rhodotorula glutinis CICC 31643 using sugar cane molasses as carbon source was studied. In the bath cultivation, the optimal sugar concentration and initial medium pH was 20% (w/w) and 6.0, respectively. The low C/N ratio (25 and 20) was more suitable for cell growth, while high C/N ratio (100 and 50) was more suitable for oil production. The C/N ratio 100 was the most beneficial for oil production of R. glutinis CICC 31643 with a notable lipid accumulation of 44.5% (w/w). 7.93 g/l lipid production was obtained during the fed-bath cultivation, whereas 6.31 g/l lipid production was obtained during the bath cultivation. Fatty acids produced by R. glutinis CICC 31643 were composed of oleic (C18:1), palmitic (C16:0), and stearic acid (C18:0) and the palmitic and oleic acid dominated the total of the fatty acids. It is suggested that the lipid production could be suitable for the production of good quality biodiesel.</jats:p>

Yumechris Amekan

International Journal of Renewable Energy Development • 2020

<jats:p>An essential component in sustainable energy development is the production of bioenergy from waste. The most successful bioenergy technology worldwide is anaerobic digestion (AD), which is a microbially-mediated process of organic feedstock conversion into energy-rich compounds (volatile fatty acids (VFA) and biogas) for renewable energy generation. AD is deployed in a range of situations including systems for on-farm energy recovery from animal and plant waste to the processing of food and municipal solid waste (with the additional benefit of land-fill reduction).Anaerobic digesters rely on a diverse microbial community working syntrophycally through a series of interrelated biochemical processes.Each stage in anaerobic digestion is carried out by different microbial groups. Thus, to optimise energy recovery from the AD process, the microbial community must have stable performance over time, balancing the various metabolic functions and taxonomic community composition in digesters. Complicating this balance, it has been found that the presence of ammonia, sulphate, and hydrogen sulphide in substantial concentrations often cause failure in the AD process. Thus, these substances cause adverse shifts in microbial community composition and/or inhibit bacterial growth, that influencing AD performance.  ©2020. CBIORE-IJRED. All rights reserved</jats:p>

Praveen C. Ramamurthy, Simranjeet Singh, Dhriti Kapoor et al.

Microbial Cell Factories • 2021

<jats:title>Abstract</jats:title><jats:p>The accelerating energy demands of the increasing global population and industrialization has become a matter of great concern all over the globe. In the present scenario, the world is witnessing a considerably huge energy crisis owing to the limited availability of conventional energy resources and rapid depletion of non-renewable fossil fuels. Therefore, there is a dire need to explore the alternative renewable fuels that can fulfil the energy requirements of the growing population and overcome the intimidating environmental issues like greenhouse gas emissions, global warming, air pollution etc. The use of microorganisms such as bacteria has captured significant interest in the recent era for the conversion of the chemical energy reserved in organic compounds into electrical energy. The versatility of the microorganisms to generate renewable energy fuels from multifarious biological and biomass substrates can abate these ominous concerns to a great extent. For instance, most of the microorganisms can easily transform the carbohydrates into alcohol. Establishing the microbial fuel technology as an alternative source for the generation of renewable energy sources can be a state of art technology owing to its reliability, high efficiency, cleanliness and production of minimally toxic or inclusively non-toxic byproducts. This review paper aims to highlight the key points and techniques used for the employment of bacteria to generate, biofuels and bioenergy, and their foremost benefits.</jats:p>

Michael R. Hays, Jeffrey Morton, William S. Oates et al.

ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, Volume 1 • 2011

<jats:p>Electrically controlled adaptive materials are ideal candidates for developing high agility micro-air-vehicles (MAV) due to their intrinsic multi-functionality. The dielectric elastomer VHB 4910 is one such material, where deformation occurs with an applied electric field. Here, we study the aerostructural response and control authority of a VHB 4910 membrane wing. An experimental membrane-wing platform was constructed by stretching VHB 4910 over a rigid elliptical wing-frame. The low Reynolds number (chord Reynolds number &lt; 106) aerodynamics of the elliptical wing were characterized with different electrostatic fields applied. We observe an overall increase in lift with maximum gains of 20% at 4.5 kV, and demonstrate the ability to delay stall. Aerodynamic effects are investigated with membrane displacement and strain data obtained through visual image correlation (VIC). The VIC data is compared to a finite deforming finite element shell model to help understand structural shape changes under electrostatic fields and low Reynolds number aerodynamic flows. The model is formulated to directly input three dimensional membrane displacements to quantify aerodynamic loads on the electroactive membrane surface.</jats:p>

David Gonzalez Rodriguez, Cole Maynard, Julio Hernandez et al.

ASME 2022 Conference on Smart Materials, Adaptive Structures and Intelligent Systems • 2022

<jats:title>Abstract</jats:title> <jats:p>Flexible sensors have demonstrated great potential for utilization in many industrial applications due to their ability to be produced in complex shapes. Sensors are employed to monitor and detect changes in the surrounding environment or the structure itself. A great majority of these flexible structures are produced by casting processes, since they are generally composed of silicone materials due to their high elasticity and flexibility. Unfortunately, the casting process is time consuming, and it limits the development of complex geometries reducing the advantages of silicone materials. 3D printed flexible sensors have demonstrated great potential for utilization in a variety of different applications including healthcare, environmental sensing, and industrial applications. In recent years, research on these topics has increased to meet low-cost sensing needs due to the development of innovative materials and printing techniques that reduce cost, production time, and enhance the electrical and mechanical properties of the sensors. This paper presents a 3D printed flexible dielectric electroactive polymer (DEAP) sensor capable of producing an output signal based on the deformation caused by external forces. Three different conductive flexible filaments were tested, using one commercial filament and two custom-made filaments, a comparison of its sensing behavior is also presented herein. Additionally, computational simulations were done to evaluate the performance of the produced sensors, evaluating the capacitance change of the entire structure. This work demonstrates the production of 3D printed flexible sensors and studies the behavior of new customizable conductive flexible filaments. Both manufactured sensors were produced using fused deposition modeling (FDM) techniques.</jats:p>

Carlo Santoro, Sofia Babanova, Plamen Atanassov et al.

ECS Meeting Abstracts • 2014

<jats:p>Microbial fuel cell (MFC) is a bioelectrochemical capable of oxidizing organics compounds and generating electricity simultaneously. The ultimate goal would be to realize a low cost treatment system that would work in self-sustainable. In order to achieve that, our groups are moving towards materials study, characterization, modification and development and optimization with the vision of scaling up BES. </jats:p> <jats:p>Several sets of anodes carbonaceous and metallic materials have been investigated. Carbonaceous materials have been investigated and functionalized with chemical and electrochemical technique in order to increase oxygen and nitrogen functional groups that allow faster and higher bacteria attachment enhancing the biofilm electro-activity and electrons generation. Unfortunately, carbonaceous materials are very expensive and not enough robust to be deployed in long terms operation. As alternative, stainless steel (SS304) commercially available plain sheet has been investigated achieving similar performances compared to carbonaceous-based electrodes. The establishment of strictly anaerobic conditions in a short amount of time guaranteed also the conditions necessary to avoid metal corrosion. SS304 looks to be promising for large-scale applications due to the materials robustness and very reduced cost (order of magnitudes lower than carbonaceous-based groups). Further studies are currently in progress towards the direction of optimizing the SS304 material adding functional groups, hierarchically organized carbon structures and protecting the SS from long term possible deterioration and corrosion. </jats:p> <jats:p>Several sets of cathodes have been deployed also in order to replace the more expensive and utilized platinum and guarantee long terms conditions. Cathodes based on cheap and high surface area activated carbon has been deployed for treating wastewaters. Other efficient, highly active and low cost catalysts based on non-PGM catalysts have been also studied with high performances and actually better behavior of platinum in SCMFC due to the establishment of highly alkaline conditions in proximity of the cathode. Moreover, those catalysts showed a better resistance to get pollutants from toxic compounds naturally present into wastewater. The low cost, high performance and reduced possibility to get poisoned make non-PGM a suitable choice of catalysts to be deployed in BESs.</jats:p> <jats:p> </jats:p>

Irene S. Asetre, L. Tayo

2021 10th International Conference on Renewable Energy Research and Application (ICRERA) • 2021

Microbial fuel cell (MFC) systems are promising technologies that pose as an efficient alternative renewable energy source. This study evaluated the performance of MFCs inoculated with active soil microorganisms and fed with crab meat processing wastewater, using different proton exchange membranes and different electrode materials, in the production of bioelectricity and chemical oxygen demand (COD) reduction. MFC’s performance were analysed in terms of power density, energy output and COD reduction. COD concentrations were measured using standard Hach® COD kit Method 8000 with high range mercury vials. MFC reactors using titanium mesh wire electrodes demonstrated high open circuit potential (OCP) with peak values of 967 mV and 960 mV for MFC with Nafion membrane (MFC-Nafion) and MFC with gelatinised tapioca starch (MFC-GTS), respectively. Average power density output in closed circuit conditions peaked to as high as 9,908.52 mW/m3 for MFC-GTS reactor using carbon fiber brush electrodes. Energy plotted peaked at 235.88 J for MFC-GTS as a function of time calculated from geometric areal power density. COD reduction in MFC-GTS reactor was 31.05% and 36.06% using titanium wire mesh and carbon fiber brush electrodes, respectively. These results revealed that MFCs inoculated with active soil microbes using organic GTS membrane is a promising technology for bioenergy generation and COD reduction.

M. Then, S. Ramesh, M. Asrul et al.

IOP Conference Series: Materials Science and Engineering • 2021

Hydrogen has a great potential as an alternative energy and produces zero emissions, but most of hydrogen is produced from non-renewable fossil fuels via reforming. Thus, biomass is a promising replacement to fossil fuels where hydrogen can be sourced from. In this project, sago waste is chosen as raw material in a microbial electrolysis cell (MEC) to produce hydrogen fuel. A mathematical model with the integration of MEC with photo-fermentation has been developed and modified by using sago effluent as a substrate in a batch process. The main parameter such as concentration of microbial community has been observed in this project as it gives a huge influence on the gas product of MEC. In conclusion, the develop model was to observe the behavior of the microbial electrolysis cell where a maximum of 3.8 L/day (t = 4 days) of hydrogen production and 0.38A of MEC current were obtained.

A. Rosmalia, N. Dewi, I. Permana et al.

IOP Conference Series: Earth and Environmental Science • 2022

Asynchronous releasing rumen degradable protein (RDP) and energy reduces rumen microbial protein synthesis (MPS) and increases excess nutrients to the environment. Moreover, the ratio of RDP to rumen undegradable protein (RUP) was also important in improving the utilization of protein, especially for high-producing cows. However, the issue has not been a concern of most dairy concentrate manufacturers in tropical areas. The objective of this study was to determine the optimal ratio of RDP to RUP (RDUP) at different energy levels (TDN) of dairy cattle concentrate using in vitro method. The study used a 4 × 3 factorial randomized block design. The first factor was RDUP (1.50; 1.22; 1.00; 0.82) and the second factor was TDN levels (65%; 70%; 75%). Data were analyzed using ANOVA and followed by Duncan’s test. RDUP and TDN treatments affected NH3 concentration without interaction. Total VFA concentration, rumen bacteria, and protozoa population did not affect by the treatments. Dry matter and organic matter digestibility increased with increasing RDUP and TDN levels with an average of 71.58% and 70.67%, respectively. It is concluded that dairy concentrate based on RDP:RUP ratio at 1.50 (60:40) and 75% TDN improves fermentability and in vitro digestibility.

Attila Tókos, Monica Jipa, G. Cîrciumaru et al.

2022 International Conference on Electrical, Computer and Energy Technologies (ICECET) • 2022

In this paper, a system to stimulate in extremely low frequency (ELF) electric field the microbiological activity of the microbial flora in the active sludge of a wastewater treatment plant is presented. The designed and realized system was tested in industrial environment with and without ELF electric field stimulation. By comparing the two cases for the same degree of pollutants elimination from the wastewater, it resulted that the ELF electric field application significantly reduces the processing times in the biological treatment stages (to approximately half). Thus, the energy consumption in the biological treatment stage is reduced by approx. 50%, representing approx. 30% of the wastewater treatment plant energy consumption.

T. Luong, Stewart J. Thomas

Proceedings of the 20th ACM Conference on Embedded Networked Sensor Systems • 2022

With an ongoing search for alternative energy sources, plants may serve as a viable means for operating low-power digital circuits. Biopotential, the electrical signals found within the body due to electrochemical activity, can be monitored and harnessed within plants and vegetables. Measuring plant biopotential, in combination with electrogenic microbial fuel cell (MFC) technology [14], suggests that a self-sufficient and micro-power generation system can be made using a microbial fuel cell in tandem with a living plant [18]. This research presents ongoing work in proposed sub-systems within this power generation system and their compatibility with low-power electronics, a project inspired from works focused on converting plants into batteries [7, 8]. The power harvesting aspect of the project consists of long deployment experiments with mud based MFCs using MudWatt kits, as well as a plant based MFC. The plant sensing aspect of the project is depending on thigmonastic reactions from the plant specie Mimosa pudica.

Nan Xiao, Rong Wu, J. Huang et al.

2019 IEEE SENSORS • 2019

The rapid quantification of biological oxygen demand (BOD) plays an important role in monitoring water quality as well as its management in municipal wastewater treatment. Conventional methods based on consumption of dissolved oxygen over 5 days are slow, labor-intensive and usually require skilled personnel and a well-equipped laboratory. Microbial fuel cells (MFCs) have the ability to convert energy from the chemical form to electrical form and could be used directly measure BOD in an automated way. Nevertheless, these transducers are large, expensive and have a relatively long response time which limits their application as BOD sensors. Here, we use xurographic fabrication technology to rapidly fabricate a low cost micro-MFC and demonstrate its suitability to measure BOD. The miniaturized sensor was fabricated in 10 min, with small reaction volume of only 1.8 µL resulting in a faster response time of only 1.1 min and a larger detection range of 18492 mg/L BOD. These findings demonstrate that the use of xurographic methods to fabricate MFCs can enable low cost measurement of BOD in a rapid manner. These sensors have potential for application in wastewater treatment plants for both monitoring as well as control.

P. Serra, A. Espírito-Santo, A. Albuquerque

2015 IEEE International Conference on Industrial Technology (ICIT) • 2015

The improvement of methods to harvest the energy produced by a Microbial Fuel Cells is receiving growing attention from the scientific community. The motive is related with the possibility to join the wastewater treatment process with the production of energy. This last process is strongly dependent from several biochemical parameters that can affect the energetic efficiency of the MFC. The experimental setup here proposed allows the correlation of MFC's operating conditions with the energetic productivity. The mechanisms that manage the mode how energy is extracted from the cell can be improved based on the experimental information obtained from the proposed setup.

Ghaibulna Abdol Lajis, J. Jasni, Mohd Faizuddin Kamaruddin et al.

2022 IEEE International Conference on Power and Energy (PECon) • 2022

Sustainability has been one of the most important topics discussed lately-part of sustain ability strategies focusing on global warming and food security issues. Alternative energy sources of various kinds have been explored and applied to mitigate the impact of fossil fuels in the last decade. The electricity generation from living plants has evolved as a new alternative renewable energy source known as a plant microbial fuel cell (PMFC). This paper investigated the bioelectricity generation in economic crops at aquaponics systems using PMFC. The result reveals that economic crops could generate bioelectricity using the PMFC. In the experiment, a single-chamber PMFC configuration was conducted on two economic crops, chilli and okra, with graphite felt as an electrode. As a result, chilli generated 19.58 nW while okra generated 17.00 n W, where chilli outperformed the okra in terms of power generation.

J. Prasad, R. K. Tripathi

2018 2nd IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems (ICPEICES) • 2018

This paper presents sediment microbial fuel cell (SMFC) and a Dc-Dc boost converter. In which, an SMFC generates a maximum voltage of 1.16V, which is not sufficient to drive the low power electronic device. Therefore, a self-sustainable Dc-Dc boost converter is designed to boost up the SMFC voltage from 1.161V to 3.289V. This is simulated in the LTspice software by using an LTC3108 integrated circuit (IC). The performance of this proposed boost converter is analyzed at different load resistance. During the analysis, we found that output voltage and current of the boost converter are almost constant when the load resistance made equal to the internal resistance of the SMFC. The energy harvester Dc-Dc boost converter can deliver upto 3.289V, which is sufficient to power sensor devices, remote water sensing and other remote broadcasts etc. The proposed Dc-Dc boost converter is self-sustainable because it is powered entirely from harvested energy without requiring extra external power sources.

M. Shahparasti, J. Rocabert, R. Muñoz et al.

2018 7th International Conference on Renewable Energy Research and Applications (ICRERA) • 2018

In this paper, a new type of single-stage interlinking converters for Microbial Electrosynthesis (MES) energy storage applications connected to the three-phase grid is presented, in which impedance source network (ZSN) is employed to reduce cost and volume, and meanwhile improve the efficiency. Impedance source converter (ISC) with buck-boost characteristic is able to feed MES with a wide range of voltages in DC side, also, converter grid distortion in AC side is reduced because there is no need to dead time for switching. Different ZSNs are studied and discussed for MES energy application. The applicable ones are selected and a comprehensive comparison is presented. Also, the proposed efficient control for ISC consists of two parts, first ZSN capacitor control plus reactive power control are done by controlling modulation index, and second the objective of tracking active power reference can be achieved by means of controlling shoot-through duty cycle. Simulation results are presented to certify the comparison between ZSNs and to verify the merit of the proposed control scheme.

E. M. Putri, M. Zain, L. Warly et al.

IOP Conference Series: Earth and Environmental Science • 2024

The traditional approach to feeding ruminant is based on the needs of protein and energy to enhance production and productivity. It is crucial to note the protein degradability in feed as microbial rumen needs ammonia from rumen degradable protein (RDP), while ruminant needs bypass protein also known as rumen undegradable protein (RUP) alongside microbial crude protein. Through the use of an in vitro technique, the recent study aimed to determine the optimal level of protein, energy, and RDP:RUP ratio in the diet of beef cattle by observing VFA partial production, protozoa population, and methane gas emissions. Various dietary treatments were formulated (based on dry matter content) comprised three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels(55:45 for low RDP, 60:40 for medium RDP, and 65:35 for high RDP). The study followed 3x3x2 factorial randomized block design with three replications. The dietary treatments were incubated with buffered rumen fluid. This study showed acetic, propionic, and butyric acid production were influenced by protein, energy, RD:RUP ratio (P<0.05). Meanwhile, protozoa population and methane gas emission were reduce by dietary protein, energy, and RDP:RUP ratio. In summary, dietary protein, energy, and RDP:RUP ratio impacts the production of VFA, protozoa population, and methane gas emissions. The diet comprising 14% dietary protein, 70% energy, and 60%:40% of RDP: RUP optimizes the production of VFA, while simultaneously reducing protozoa population and methane gas emissions.