Electricity generation of bacterial communities changes with the mineralization of organic matter in microbial fuel cells (MFCs) (original) (raw)
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International Journal of Environmental Science and Technology
Microbial fuel cells is growing technology for energy production (electrical and gaseous) with potential electrochemically active bacteria from degradation of unwanted contaminants. Electrogenic [petroleum-contaminated soil (PCS) and hot spring water HSW)] and electrotrophic [activated sludge] bacterial communities were enriched and evaluated for electric current production in biocathode microbial fuel cells (MFC). Molecular phylogenetic (454 pyrosequencing) analysis of environmental samples revealed an overall change in bacterial density and diversity after second-stage enrichment. The predominant electrogenic bacteria grown at anodic biofilms belonged to phylum Proteobacteria (80-98%) in both MFC-1 (PCS) and MFC-2 (HSW) reactors. After enrichment, the major shift in the bacterial species on anodic surface was observed in case of Stenotrophomonas maltophilia (89%) and shewanella sp. (15%) in the respective reactors. Overall, among electrotrophic bacteria, the relative abundance (27-30%) of Pseudomonas aeruginosa was maximum on the cathodic biofilm in both fuel cells. Scanning electron and confocal laser scanning microscopies of biofilms revealed that anode and cathode surfaces were covered with different microcolonies and dispersed bacterial cells. Cyclic voltammetry (− 1 to 1 V vs. Ag/AgCl) further confirmed the presence of highly proficient electrogenic bacteria capable of generating high electricity ranging from ≥ 8 mA in MFC-1 and ≤ 0.37-Y in MFC-2. Maximum power density of 5500 mW m −2 at a current density of 100 mA m −2 (550 Ω)] was recorded in MFC-1 during enrichment stage 2; however, it (P max = 1201 mW m 2) remained 78% lower in MFC-2. Fourier transform infrared spectroscopy and COD removal [86% (SD = 8.3 ± 2.0)] of anolyte (PCS) confirmed active degradation of petroleum contaminants during the operation of MFC-1.
Biotechnology for Biofuels and Bioproducts
Background Microbial fuel cells (MFCs) are among the leading research topics in the field of alternative energy sources due to their multifunctional potential. However, their low bio-energy production rate and unstable performance limit their application in the real world. Therefore, optimization is needed to deploy MFCs beyond laboratory-scale experiments. In this study, we investigated the combined influence of electrode material (EM), electrode spacing (ES), and substrate feeding interval (SFI) on microbial community diversity and the electrochemical behavior of a soil MFC (S-MFC) for sustainable bio-electricity generation. Results Two EMs (carbon felt (CF) and stainless steel/epoxy/carbon black composite (SEC)) were tested in an S-MFC under three levels of ES (2, 4, and 8 cm) and SFI (4, 6, and 8 days). After 30 days of operation, all MFCs achieved open-circuit voltage in the range of 782 + 12.2 mV regardless of the treatment. However, the maximum power of the SEC–MFC was 3.6 ti...
Jurnal Kejuruteraan, 2019
Soil Microbial Fuel Cell (SMFC) is a device that using bacteria in soils as a biocatalyst. These bacteria, called exoelectrogenic bacteria are oxidizing organic substrates to release electrons, which then harvested in an external circuit to produce bioelectricity. Despite all the potential, the bioelectricity production from soils is still low and its relation with SMFC conditions is uncertain. Hence, the main objective in this study is to enhance and stabilize the bioelectricity production of SMFC by additional glucose, nutrient broth and Escherichia coli (E. coli) as exoelectrogenic bacteria. A number of factors of SMFC performance were first identified to be preliminary investigated, that is the type of electrode, water addition to soil and distance between anode to cathode. It has been established in this study to use SMFC with the configuration of 9.5 cm in diameter and 15 cm height of the plastic container, with the 12 cm distance between carbon felt of anode and cathode. The electricity produced was measured by using a multimeter in term of voltage reading (mV). From this study, the highest bioelectricity produced was obtained from SMFC using nutrient broth with a maximum voltage of 700 mV. It has found that the additional E. coli bacteria did not increase the bioelectricity production. The use of E. coli needed to be combined with nutrient broth in order to achieve high and stable bioelectricity. It can be suggested that the indigenous bacteria that exist in the soils possibly played the role in producing bioelectricity.
ChemSusChem, 2021
In memory of Dr. Alessandra Colombo A cross-laboratory study on microbial fuel cells (MFC) which involved different institutions around the world is presented. The study aims to assess the development of autochthone microbial pools enriched from domestic wastewater, cultivated in identical single-chamber MFCs, operated in the same way, thereby approaching the idea of developing common standards for MFCs. The MFCs are inoculated with domestic wastewater in different geographic locations. The acclimation stage and, consequently, the startup time are longer or shorter depending on the inoculum, but all MFCs reach similar maximum power outputs (55 � 22 μW cm À 2) and COD removal efficiencies (87 � 9 %), despite the diversity of the bacterial communities. It is inferred that the MFC performance starts when the syntrophic interaction of fermentative and electrogenic bacteria stabilizes under anaerobic conditions at the anode. The generated power is mostly limited by electrolytic conductivity, electrode overpotentials, and an unbalanced external resistance. The enriched microbial consortia, although composed of different bacterial groups, share similar functions both on the anode and the cathode of the different MFCs, resulting in similar electrochemical output.
Journal of Bioscience and Bioengineering, 2013
It is important for practical use of microbial fuel cells (MFCs) to not only develop electrodes and proton exchange membranes but also to understand the bacterial community structure related to electricity generation. Four lactate fed MFCs equipped with different membrane electrode assemblies (MEAs) were constructed with paddy field soil as inoculum. The MEAs significantly affected the electricity-generating properties of the MFCs. MEA-I was made with Nafion 117 solution and the other MEAs were made with different configurations of three kinds of polymers. MFC-I equipped with MEA-I exhibited the highest performance with a stable current density of 55 ± 3 mA m L2 . MFC-III equipped with MEA-III with the highest platinum concentration, exhibited the lowest performance with a stable current density of 1.7 ± 0.1 mA m L2 . SEM observation revealed that there were cracks on MEA-III. These results demonstrated that it is significantly important to prevent oxygen-intrusion for improved MFC performance. By comparing the data of DGGE and phylogenetic analyzes, it was suggested that the dominant bacterial communities of MFC-I were constructed with lactate-fermenters and Fe(III)-reducers, which consisted of bacteria affiliated with the genera of Enterobacter, Dechlorosoma, Pelobacter, Desulfovibrio, Propioniferax, Pelosinus, and Firmicutes. A bacterium sharing 100% similarity to one of the DGGE bands was isolated from MFC-I. The 16S rRNA gene sequence of the isolate shared 98% similarity to grampositive Propioniferax sp. P7 and it was confirmed that the isolate produced electricity in an MFC. These results suggested that these bacteria are valuable for constructing the electron transfer network in MFC.
Electrical Stress-Directed Evolution of Biocatalyst Texcoco Soil Community for Microbial Fuel Cell
ECS Transactions, 2019
Anode-respiring bacteria (ARB) perform an unusual form of respiration in which their electron acceptor is a solid anode. The focus of this study was to characterize the electrical stress direct evolution of biocatalysts as a way of enriching the community with ARB for microbial fuel cell. The original microbial consortium was sampled from a sodic-saline soil (Texcoco Lake). Interestingly, the most probable number of iron (III) reducing bacteria in the original consortium was 8500 ± 15 MPN/100 mL, since iron (III) is reported to be associated to anode-respiring capabilities. Cyclic voltammetry studies of electrochemical stressed biofilm-ARB were conducted at 135 th day, and an irreversible electron transfer reaction of alkaliphilic cytochrome, due to the electrode fouling was found. The electrochemical impedance spectroscopy results revealed that the resistance of the biofilm-ARB decreases with the time, associated to the adaptability of electroactive biofilm on the graphite electrode surface. Confocal microscopy revealed that the biofilm-ARB attained ~40 µm thickness. Electrical stressed-ARB gave a maximum power density of 79.44 mW/m 2 , which was greater than that obtained by the chemical stressed-ARB (48.48mW/m 2) in a single-chamber microbial fuel cell (SCMFC).
Assessing the effect of the electrode orientation on the performance of soil microbial fuel cells
E3S Web of Conferences, 2022
Soil microbial fuel cells (SMFCs) are a sub-class of the microbial fuel cells family, in which the soil acts as the electrolyte, and as the source of microorganisms and organic fuel. Given the great simplicity of the system design, SMFCs show a promising avenue for energy generation in remote areas. In this study, we investigate the influence that geometrical factors, such as the electrode orientation, have on the electrochemical performance of SMFCs. Two types of electrode orientations: horizontal and vertical, were tested. Additionally, the influence of anode and cathode immersion in soil was explored too. Our results demonstrate that vertical positioning of the cathode in soil is not a viable option. The increase in cathodic immersion leads to a more rapid performance decay, attributed to more anaerobic conditions along soil’s depth. The increase in anode immersion has a positive effect on the evolution of the negative electrode potential. However, with the increase in electrode ...
Energy, 2016
Microbial Fuel Cells (MFC) are bio-electrochemical systems that convert chemical energy into electrical energy from the respiratory metabolic profit of electrochemically active bacteria. In order to contribute to a greater understanding regarding the MFCs performance, real-time quantitative PCR was applied to determining typical planktonic bacteria in the production of electricity in MFCs, evaluating their relations with different carbon-based anode materials: carbon felt (C-FELT), carbon felt with polyaniline (C-PANI) and carbon-coated Berl saddles (C-SADDLES). Bacteria distribution among the three different MFC anode materials was evaluated: statistically significant differences were detectable for total bacteria (p < 0.01), Geobacter (p < 0.05) and Shewanella (p < 0.05), due to a greater abundance in C-FELT anode MFC. Significant difference (p < 0.001) was shown for maximum power density: C-PANI showed a maximum power density of 28.5 W/m3 with respect to C-FELT (4.7 W/m3) and C-SADDLES (4.6 W/m3). In general the largest electrochemically active planktonic microbes was present in the C-FELT while the best carbon-based anode materials results C-PANI.