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Microbial fuel cell (MFC) technology has been investigated for over a decade now and it has been deemed as a preferred technique for energy generation since it is environmentally benign and does not produce toxic by/end products. However, this technology is characterized by low power outputs, poor microbial diversity detection, and the presence of...
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... mediators are, therefore, employed to render electron transfer from the microbial cells to the electrode. It may be noted that the overall efficiency of the electron transfer mediators also depends on many other parameters, and in particular on the electrochemical rate constant of the mediator re-oxidation, which depends on the electrode material (Fig. ...
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... In the intracellular metabolic process, NADH and FADH2 undergo reduction by accepting electrons and protons. This reduction allows them to participate in the electron transfer chain, thereby generating the cell's energy currency [145]. Electrochemically active microbes employ various EET mechanisms, including nanowires (pili-like structures), c-type cytochromes (heme-containing proteins in the periplasm and outer membrane), and electron shuttles (organic molecules like flavins and pyocyanin, capable of redox reactions) [145] (Fig. 2). ...
... This reduction allows them to participate in the electron transfer chain, thereby generating the cell's energy currency [145]. Electrochemically active microbes employ various EET mechanisms, including nanowires (pili-like structures), c-type cytochromes (heme-containing proteins in the periplasm and outer membrane), and electron shuttles (organic molecules like flavins and pyocyanin, capable of redox reactions) [145] (Fig. 2). ...
... Microalgae other than Microcystis aeruginosa have been widely employed as electron donors or oxygen producers in photomicrobial fuel cells [25]. There have been very few studies that have reported MFCs' use of hazardous algal biomass [26][27][28]. For example, with the elimination of MC-LR, cyanobacteria were employed to power the single-chamber MFC [29]. ...
... Elshobary et al. [65] stated that the use of these photosynthetic organisms (algae) in MFC could improve efficiency and provide a cost-effective and renewable method for bioelectricity generation as shown in Fig. 4. Microalgae are frequently used in MFCs' anode and cathode compartments to produce electrons and oxygen, respectively. Likewise, Mekuto et al. [27] mentioned that microalgae-assisted MFC is a self-sustaining microbial fuel cell that uses a microalgae-assisted cathode to aid oxidation/reduction processes (ORR) while recycling the produced algal biomass to the anode compartment as a feedstock for increased energy output. ...
In recent years, the ecologically beneficial technique has attracted international interest as a cutting-edge technology for waste treatment and energy generation. Microbial fuel cells are devices that utilize microorganisms as biocatalysts to transform organic waste matterfor electricity generation. Recently algal biomass is getting attention by research proponents as a new innovative, sustainable source of bioenergy to fulfill the rising electricity demand with additional benefits such as bioenergy production, waste water treatment, the manufacturing of high-value products while also serving as a carbon sink. This chapter discusses the possible use of algae in bio-electrochemically oxidation processes in completely biotic MFCs for power generation, carbon sequestration and bioremediation. Furthermore, this chapter summarized current research aimed at generating various types of micro algal based MFCs. The many process aspects influencing the performance of the microalgae MFC system, as well as some technology impediments, are also discussed with a view to the future.
... The most selected biological combinations are cyanobacteria (generally Synechocystis sp. PCC6803, autotrophic organism) and Shewanella oneidensis (heterotrophs) (Tsujimura et al., 2001;Liu and Choi, 2017;Mekuto et al., 2020). closely attached the cyanobacteria species most commonly used in BPV research to Shewanella. ...
As the most suitable potential clean energy power generation technology, biophotovoltaics (BPV) not only inherits the advantages of traditional photovoltaics, such as safety, reliability and no noise, but also solves the disadvantages of high pollution and high energy consumption in the manufacturing process, providing new functions of self-repair and natural degradation. The basic idea of BPV is to collect light energy and generate electric energy by using photosynthetic autotrophs or their parts, and the core is how these biological materials can quickly and low-loss transfer electrons to the anode through mediators after absorbing light energy and generating electrons. In this mini-review, we summarized the biological materials widely used in BPV at present, mainly cyanobacteria, green algae, biological combinations (using multiple microorganisms in the same BPV system) and isolated products (purified thylakoids, chloroplasts, photosystem I, photosystem II), introduced how researchers overcome the shortcomings of low photocurrent output of BPV, pointed out the limitations that affected the development of BPV’ biological materials, and put forward reasonable assumptions accordingly.
... also belongs. These results confirm the presence of Geobacteracea, one of the most common bacteria in the microbial consortium in MFC systems [75,76]. ...
The increased demand for alternative sustainable energy sources has boosted research in the field of fuel cells (FC). Among these, microbial fuel cells (MFC), based on microbial anodes and different types of cathodes, have been the subject of renewed interest due to their ability to simultaneously perform wastewater treatment and bioelectricity generation. Several different MFCs have been proposed in this work using different conditions and configurations, namely cathode materials, membranes, external resistances, and microbial composition, among other factors. This work reports the design and optimization of MFC performance and evaluates a hydrogel (Ion Jelly ®) modified air-breathing cathode, with and without an immobilized laccase enzyme. This MFC configuration was also compared with other MFC configuration performances, namely abiotic and biocathodes, concerning wastewater treatment and electricity generation. Similar efficiencies in COD reduction, voltage (375 mV), PD (48 mW/m 2), CD (130 mA/m 2), and OCP (534 mV) were obtained. The results point out the important role of Ion Jelly ® in improving the MFC air-breathing cathode performance as it has the advantage that its electroconductivity properties can be designed before modifying the cathode electrodes. The biofilm on MFC anodic electrodes presented a lower microbial diversity than the wastewater treatment effluent used as inocula, and inclusively Geobacteracea was also identified due to the high microbial selective niches constituted by MFC systems.
... Biomass and oxygen are produced during the light period and the algae consume the oxygen produced and reduce the organic matter during the dark period. Further, it was found that red light with high intensity (900 lux) gave better power output as compared to blue light with low intensity (100-600 lux) (Jaiswal et al., 2020;Mekuto et al., 2020). This occurs due to the high absorption of light energy by the photosynthetic system of algae at this wavelength. ...
... DO increases with an increased rate of photosynthesis, which resulted in an increase of cathodic resistance. In some cases, the anode department is covered to prevent the growth of algae along the anode (Mekuto et al., 2020). This system had a higher voltage and power density compared to uncovered anodic chamber (Jaiswal et al., 2020). ...
... Moreover, easily degradable substances cannot sustain long-term bioelectricity generation and hence long-release substrates should be explored that will help in self-sustained bioelectricity production (Qi et al., 2018). Besides supplying oxygen in the cathode, algae can also be used as substrate at anode in the form of either live cells or powdered form or as dead biomass or pretreated biomass or after extraction of lipids (Shukla & Kumar, 2018), which will reduce the cost sufficiently and create a closed-loop system (Mekuto et al., 2020). As this setup is being tested for wastewater remediation with simultaneous bioelectricity generation, various wastewater sources have also been used as substrates like swine wastewater (Zhang et al., 2019), kitchen wastewater (Naina Mohamed et al., 2020), anaerobic sludge (Ma et al., 2017), paper recycling wastewater (Radha & Kanmani, 2017), food-based wastewater (Saba et al., 2017), dye wastewater (Enamala et al., 2020), brewery wastewater (Harewood et al., 2017), landfill leachate (Hernández-Flores et al., 2017), fermentation effluents (Dai et al., 2021), dairy wastewater (Choudhury et al., 2021), oil refinery wastewater (Ng et al., 2021), pharmaceutical wastewater (Nayak & Ghosh, 2019) etc. ...
... In a PMFC, the light as well as the microbes jointly help in raising the cells voltage, resulting in more electricity production [15][16][17]. A variety of microorganisms have been used in PMFC, which photosynthesize and are characterized as anodic microbes that generally include cyanobacteria, the blue green algae which takes its energy from photosynthesis [18]. On the other hand, microalgae are operative at the cathodes, which besides generating bioelectricity can also produce O 2, biofuels, carbohydrates, proteins, and carotenoids [19][20][21]. ...
... Several studies have examined the different types of the algal photosynthetic organism such as Chlorella, Desmodesmus, Scenedismus, blue-green algae, marine algae, Laminaria, Chlamydomonas reinhardtii, and mixed cultures as biocathode (Gadhamshetty et al. 2013;Gonzalez Del Campo et al. 2015;Uggetti and Puigagut 2016;Saba et al. 2017;Kakarla and Min 2019;Arun et al. 2020) and reported a maximum power density of 110 mW/m 2 in using mixed algae in catholyte (Strik et al. 2011). Additionally, algae can be used in anolyte since its biomass contains carbohydrates, vitamins, and lipids and is a rich feed for anode microbes (Khandelwal et al. 2018;Mekuto et al. 2020). In fact, the growth of anode microbes accelerates the electron transfer on the anode electrode by various mechanisms (Mekuto et al. 2020). ...
... Additionally, algae can be used in anolyte since its biomass contains carbohydrates, vitamins, and lipids and is a rich feed for anode microbes (Khandelwal et al. 2018;Mekuto et al. 2020). In fact, the growth of anode microbes accelerates the electron transfer on the anode electrode by various mechanisms (Mekuto et al. 2020). A power density of 2.7 W/m 3 was recorded by employing microalgae biomass in the anode (Khandelwal et al. 2018). ...
... This experiment was performed in batch-fed mode and investigated the simultaneous use of Synechococcus sp. in both the cathode (as an electron acceptor) and the anode chambers (as an electron donor). As a novel idea, the application of Synechococcus in the anodic chamber can be useful for producing electricity, while Synechococcus is the nutrition source for microbes and an electron donor acting as a catalyst (Gude 2016;Shukla and Kumar 2018;Mekuto et al. 2020). As exhibited, the primary open-circuit voltage was about 183.5 mV, which became stable at 452.2 mV over 6 days. ...
Photosynthetic microbial fuel cell (PMFC) is a novel technology, which employs organic pollutants and organisms to produce electrons and biomass and capture CO2 by bio-reactions. In this study, a new PMFC was developed based on Synechococcus sp. as a biocathode, and dairy wastewater was used in the anode chamber. Different experiments including batch feed mode, semi-continuous feed mode, Synechococcus feedstock to the anode chamber, Synechococcus-Chlorella mixed system, the feedstock of treated wastewater to the cathode chamber, and use of extra nutrients in the anodic chamber were performed to investigate the behavior of the PMFC system. The results indicated that the PMFC with a semi-continuous feed mode is more effective than a batch mode for electricity generation and pollutant removal. Herein, maximum power density, chemical oxygen demand removal, and Coulombic efficiency were 6.95 mW/m2 (450 Ω internal resistance), 62.94, and 43.16%, respectively, through mixing Synechococcus sp. and Chlorella algae in the batch-fed mode. The maximum nitrate and orthophosphate removal rates were 98.83 and 68.5%, respectively, wherein treated wastewater in the anode was added to the cathode. No significant difference in Synechococcus growth rate was found between the cathodic chamber of PMFC and the control cultivation cell. The heating value of the biocathode biomass at maximum Synechococcus growth rate (adding glucose into the anode chamber) was 0.2235 MJ/Kg, indicating the cell’s high ability for carbon dioxide recovery. This study investigated not only simultaneous bioelectricity production and dairy wastewater in a new PMFC using Synechococcus sp. but also studied several operational parameters and presented useful information about their effect on PMFC performance.
... Research has been reported focused on increasing the output current. One of the main strategies reported to increase potency has been the modification of anodic and cathode materials [32][33][34][35]. However, no evidence has been found of strategies implemented to guarantee the quality of the sediments used in SMFCs. ...
Bioenergy production from sediment microbial fuel cells has gained special attention for its application as a power source for environmental sensors. A sediment microbial fuel cell is a device capable of generating energy from sediments and electrolytes present in water bodies. Numerous factors must be considered to improve cell efficiency. However, a little considered factor is the quality of the sediment that is used to feed a SMFC. This research focused on the study of sediment quality and the influence of hydrological season on the production of electrical energy. A non-divided SMFC was designed with Unidirectional Carbon Fiber as electrodes. Four SMFC were prepared for the experimental work. Two cells were fed with marine and fluvial sediments collected in the rainy season and two others with sediments, of the same origins, collected in the dry season. The electrical energy of each cell was quantified during a period of 30 days. The results showed that the season influences the production of electricity. In the rainy season, the marine sediments produce greater energy with an average of 407.83 mV. In the dry season highlighted the fluvial sediments with 700.7 mV. Power densities of 141 and 70 mW cm⁻² were achieved for marine and fluvial sediments, respectively. A preliminary identification of the microbial communities was carried out for both sediments. Correlation studies showed that electrical conductivity and salinity have a positive influence on the voltage, while temperature and dissolved oxygen have no significance.
... According to the previous research [18], the PMFC achieved a maximal OCV value of 0.81 V and a power density of 3.8 mW m -2 . Recently, microalgae have been used to develop self-sustainable MFC technology, whereas the S. platensis acted as an electrogenic microorganism and the feedstock in an anode chamber [19]. Additionally, algae's biomass contains many proteins, antioxidants, vitamins, and microelements, including iron and copper, thus being commercialized as a food supplement. ...
In this study, the GC/PEI/CNT/S.p./GOx bioanode was successfully designed using the chemical oxidized multi-walled carbon nanotubes (CNT) and Spirulina platensis-based lysates that facilitate the electron transfer and reduce the open circuit potential (OCP) drop along the electron transfer pathway. Composition, morphology and chemical modification efficiency of CNT was examined using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and simultaneous thermal analysis (STA) coupled with mass spectrometric (MS) analysis of evolving gaseous species (TG/DTA–MS). The power density generated by GC/PEI/CNT/S.p./GOx bioelectrode was 21.8 times higher if S. platensis-based lysates were applied in bioanode design (than GC/PEI/CNT/GOx bioelectrode). The magnitude of maximal power density evaluated by linear sweep voltammetry (LSV) measurements was estimated to be 3.2 μW cm−2 at 213 mV voltage, whereas the bioelectrode act as a bioanode and bare glassy carbon as a cathode in a single-compartment biofuel cell design. Furthermore, the GC/PEI/CNT/S.p./GOx bioanode shows high long-term stability, while the magnitude of power density after seven days achieved approximately 89.6 % (2.87 μW cm−2) of its initial value. The initial OCP value of bioanode with S. platensis-based lysates was found to be -156 mV, which was reduced after the addition of 12.5 mM glucose. The equilibrated average value of OCP (-259 mV vs Ag/AgCl (3 M KCl)) indicates that glucose oxidase (GOx) immobilized on CNT functionalized with S. platensis-based lysates possess superior electron transfer and reduce the OCP drop along the electron transfer pathway.
... Particularly, both the extracted oil content and the carbohydrates and protein-containing in residual microalgae biomass can serve as the anode in the fuel cell system. Particularly, both the extracted oil content and the carbohydrates and protein-containing in residual microalgae biomass can serve as the anode in the fuel cell system (Ndayisenga et al. 2018;Mekuto et al. 2020). According to a close-circuit microbial fuel cell system developed by Kakarla and Min (Kakarla and Min 2019), the CO 2 produced from the residual microalgae biomass at the anode is transferred to the cathode chamber where the CO 2 can be fixed by the fresh microalgae. ...
The inherent capability and increased efficiency of microalgae to convert sunlight into solar chemical energy are further enhanced by the higher amount of oils stored in microalgae compared to other land-based plant species. Therefore, the widespread interest in producing biofuels from microalgae has gained considerable interest among leading energy experts and researchers due to the burgeoning global issues stemming from the depletion of fossil fuel reserves, future energy security, increasing greenhouse gas emissions, and the competition for limited resources between food crops and conventional biomass feedstock. This paper aims to present the recent advances in biofuel production from microalgae and the potential benefits of microalgae in the energy and environmental sectors, as well as sustainable development. Besides, bottlenecks and challenges mainly relating to techniques of cultivation and harvesting, as well as downstream processes are completely presented. Promising solutions and novel trends for realizing strategies of producing biofuels from microalgae on an industrial and commercial scale are also discussed in detail. Alternatively, the role of microalgae in the circular economy is thoroughly analyzed, indicating that the potential of scaling up current microalgae-based production could benefit from the waste-to-energy strategy with microalgae as a key intermediate. In the future, further research into combining different microalgae biomass pretreatment techniques, separating the microalgae feedstock from the cultured media, developing new species, and optimizing the biofuel production process should be carried out to reduce the prices of microalgae biofuels.
