Raoultella electrica sp. nov., isolated from anodic biofilms of a glucose-fed microbial fuel cell (original) (raw)
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Genetics and Molecular Research, 2013
DNA extraction of bacterial consortium in MFC from an MFC. The protocol that achieved the best results was based on a previous study, but was modified by eliminating a chaotropic salt and the special columns used for nucleic acid purification. The efficiency of this less expensive and more straightforward protocol was confirmed by PCR amplification of the 16S rRNA gene and denaturing gradient gel electrophoresis analysis, which confirmed the extraction of multiple genomes. The sequences of 10 clones revealed the presence of phyla, Proteobacteria, Firmicutes and Actinobacteria, comprising both Gramnegative and Gram-positive bacteria. Some of these bacteria were identified at the genus level, e.g., Clostridium, Pseudoxanthomonas, Tistrella, and Enterobacter; these genera have been described in active sludges from wastewater treatment, supporting the congruency of our results. Therefore, this protocol is a useful tool for analysis of the bacteria responsible for energy production in MFCs.
A novel ecological role of the Firmicutes identified in thermophilic microbial fuel cells
The ISME Journal, 2008
Significant effort is currently focused on microbial fuel cells (MFCs) as a source of renewable energy. Most studies concentrate on operation at mesophilic temperatures. However, anaerobic digestion studies have reported on the superiority of thermophilic operation and demonstrated a net energy gain in terms of methane yield. As such, our studies focused on MFC operation and microbiology at 55 1C. Over a 100-day operation, these MFCs were stable and achieved a power density of 37 mW m À2 with a coulombic efficiency of 89%. To infer activity and taxonomic identity of dominant members of the electricity-producing community, we performed phylogenetic microarray and clone library analysis with small subunit ribosomal RNA (16S rRNA) and ribosomal RNA gene (16S rDNA). The results illustrated the dominance (80% of clone library sequences) of the Firmicutes in electricity production. Similarly, rRNA sequences from Firmicutes accounted for 50% of those taxa that increased in relative abundance from current-producing MFCs, implying their functional role in current production. We complemented these analyses by isolating the first organisms from a thermophilic MFC. One of the isolates, a Firmicutes Thermincola sp. strain JR, not only produced more current than known organisms (0.42 mA) in an H-cell system but also represented the first demonstration of direct anode reduction by a member of this phylum. Our research illustrates the importance of using a variety of molecular and culture-based methods to reliably characterize bacterial communities. Consequently, we revealed a previously unidentified functional role for Gram-positive bacteria in MFC current generation.
International Journal of Advance Research and Innovative Ideas in Education, 2019
Energy is the most fundamental requirement of today’s era. Energy is consumed very rapidly. The energy requirements are very increasing. Our population, abundant energy resources and industrial diversity make our self proficient enough in producing and consuming energy. This will definitely leads in contributing to the national economy. It is the fact that initially there is a cost issue with every new technology but gradually developing mind we can cope up with it. The need for optimization in cost and efficiency can create systems which are cost effective, non- hazardous in nature, commercially available, clean fuel, compete with regular ongoing systems, inherently safe in handling, having renewable power and sustainable to nature. We envision a future where industries can fulfil the growing demands in an environmentally sustainable way. Hydrogen fuel cells have the real potential to be the future technology in terms of applicability. This technology has the solution to the proble...
Electricity generation and microbial community analysis of alcohol powered microbial fuel cells
Bioresource Technology, 2007
Keywords: Biomass energy Microbial fuel cell Organic fraction of municipal solid waste 16S rRNA gene pyrosequencing a b s t r a c t The organic fraction of municipal solid waste (OFMSW), normally exceeding 60% of the waste stream in developing countries, could constitute a valuable source of feed for microbial fuel cells (MFCs). This study tested the start-up of two sets of OFMSW-fed aircathode MFCs inoculated with wastewater sludge or cattle manure. The maximum power density obtained was 123 AE 41 mW m À2 in the manure-seeded MFCs and 116 AE 29 mW m À2 in the wastewater-seeded MFCs. Coulombic efficiencies ranged between 24 AE 5% (manureseeded MFCs) and 23 AE 2% (wastewater-seeded MFCs). Chemical oxygen demand removal was >86% in all the MFCs and carbohydrate removal >98%. Microbial community analysis using 16S rRNA gene pyrosequencing demonstrated the dominance of the phylum Firmicutes (67%) on the anode suggesting the possible role of members of this phylum in electricity generation. Principal coordinate analysis showed that the microbial community structure in replicate MFCs converged regardless of the inoculum source. This study demonstrates efficient electricity production coupled with organic treatment in OFMSWfueled MFCs inoculated with manure or wastewater. ª ScienceDirect ht tp://www.elsevier.com/locate/biombioe b i o m a s s a n d b i o e n e r g y 6 7 ( 2 0 1 4 ) 2 4 e3 1 http://dx.
Do Microbial Fuel Cells have Antipathogenic Properties
Journal of Computer Science & Systems Biology, 2019
During 2015-2017 we have conducted experiments in Japan to test the capacity of microbial fuel cells (MFC) to treat different types of wastewaters (swine farm, domestic, yeast fermentation, winery, etc.) and concomitantly collecting DNA samples from MFC anodic and planktonic bacterial communities. W e analyzed these metagenomes in UK, using our new bioinformatics tool (ASAR) that allow integration of phylogenetic and functional data. Characteristic MFC communities and the associated functional signatures were shown to reflect effective waste water treatment. We also found that the fraction of opportunistic pathogenic bacteria DNA was reduced in metagenomes from MFC communities during swine waste treatment. The highest loss was recorded for Enterobacteriaceae family (such as Yersinia, Vibrio, and Shigella). The abundance of virulent genes responsible for adhesion, secretion systems, invasion and intracellular survival, as well as antibiotic resistance, associated with Firmicutes and ...
Applied Microbiology and Biotechnology, 2010
Microbial fuel cell (MFC) anode communities often reveal just a few genera, but it is not known to what extent less abundant bacteria could be important for improving performance. We examined the microbial community in an MFC fed with formic acid for more than 1 year and determined using 16S rRNA gene cloning and fluorescent in situ hybridization that members of the Paracoccus genus comprised most (~30%) of the anode community. A Paracoccus isolate obtained from this biofilm (Paracoccus denitrificans strain PS-1) produced only 5.6 mW/m 2 , whereas the original mixed culture produced up to 10 mW/m 2. Despite the absence of any Shewanella species in the clone library, we isolated a strain of Shewanella putrefaciens (strain PS-2) from the same biofilm capable of producing a higher-power density (17.4 mW/m 2) than the mixed culture, although voltage generation was variable. Our results suggest that the numerical abundance of microorganisms in biofilms cannot be assumed a priori to correlate to capacities of these predominant species for high-power production. Detailed screening of bacterial biofilms may therefore be needed to identify important strains capable of high-power generation for specific substrates.
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.
International Journal of Systematic and Evolutionary Microbiology, 2018
Abacterial strain, designated MMFC1 T , was isolated from a methanol-fed microbial fuel cell that had been inoculated with sludge obtained from a wastewater-treatment facility in a chemical plant. The strain grows by fermenting methanol to produce acetate under anaerobic conditions, while homoacetogenic growth is not observed. MMFC1 T also grows on pyruvate and lactate but not on sugars and other organic acids. Cells are curved rods and motile, have peritrichous flagella, and form endospores. The genome sequence of strain MMFC1 T supports the physiological data. Phylogenetic analysis based on the 16S rRNA gene sequence shows that strain MMFC1 T is affiliated with the family Sporomusaceae, while the closest relative is Sporomusa ovata with nucleotide-sequence similarity of 93.5 %. Major fatty acids are iso-C 13 : 0 3-OH, C 16 : 1 !9 and iso-C 17 : 0. On the basis of its physiological, genomic and phylogenetic features, a novel genus and species are proposed to accommodate strain MMFC1 T , with the name Methylomusa anaerophila gen. nov., sp. nov. The type strain of Methylomusa anaerophila is MMFC1 T (=JCM 31821 T = KCTC 15592 T).
Bacterial community structure, compartmentalization and activity in a microbial fuel cell
Journal of Applied Microbiology, 2006
Aims: To characterize bacterial populations and their activities within a microbial fuel cell (MFC), using cultivation-independent and cultivation approaches. Methods and Results: Electron microscopic observations showed that the fuel cell electrode had a microbial biofilm attached to its surface with loosely associated microbial clumps. Bacterial 16S rRNA gene libraries were constructed and analysed from each of four compartments within the fuel cell: the planktonic community; the membrane biofilm; bacterial clumps (BC) and the anode biofilm. Results showed that the bacterial community structure varied significantly between these compartments. It was observed that Gammaproteobacteria phylotypes were present at higher numbers within libraries from the BC and electrode biofilm compared with other parts of the fuel cell. Community structure of the MFC determined by analyses of bacterial 16S rRNA gene libraries and anaerobic cultivation showed excellent agreement with community profiles from denaturing gradient gel electrophoresis (DGGE) analysis. Conclusions: Members of the family Enterobacteriaceae, such as Klebsiella sp. and Enterobacter sp. and other Gammaproteobacteria with Fe(III)-reducing and electrochemical activity had a significant potential for energy generation in this system. Significance and Impact of the Study: This study has shown that electrochemically active bacteria can be enriched using an electrochemical fuel cell.
2013
The number of investigation of alternative energy sources to fossil fuel is a testimony of the global awareness of the risk of air pollution. The microbial fuel cells (MFC) system contributes to the approach of green and cheap energy. The system operates with microorganisms responsible of the degradation of organic matters for production of electron and protons require in the generation of electricity. The performance of the MFC is mainly dependent on the nature of the microorganisms present and their ability to actively use the nutrients. In this study the determination of the strain composition of the microbial community in the MFC was mainly done using gene sequencing and the level of intermediate metabolites was simultaneously assessed to both monitor microbial activities and the effect of these metabolites on their growth. Several strains of microorganisms (46 in total) were identified in the anode compartment with potential of carbohydrate oxidation and electron transfer. The ...