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Alastair W Tait, Emma J Gagen, Siobhan A Wilson, Andrew G Tomkins, Gordon Southam
Finding fresh, sterilized rocks provides ecologists with a clean slate to test ideas about first colonization and the evolution of soils de novo. Lava has been used previously in first colonizer studies due to the sterilizing heat required for its formation. However, fresh lava typically falls upon older volcanic successions of similar chemistry and modal mineral abundance. Given enough time, this results in the development of similar microbial communities in the newly erupted lava due to a lack of contrast between the new and old substrates...
2017: Frontiers in Microbiology
Brigitte Delord, Wilfrid Neri, Karen Bertaux, Alain Derre, Isabelle Ly, Nicolas Mano, Philippe Poulin
Novel carbon nanotube based electrodes of microbial fuel cells (MFC) have been developed. MFC is a promising technology for the wastewater treatment and the production of electrical energy from redox reactions of natural substrates. Performances of such bio-electrochemical systems depend critically on the structure and properties of the electrodes. The presently developed materials are made by weaving fibers solely comprised of carbon nanotubes. They exhibit a large scale porosity controlled by the weaving process...
July 1, 2017: Bioresource Technology
Yaohuan Gao, Jangho Lee, Josh D Neufeld, Joonhong Park, Bruce E Rittmann, Hyung-Sool Lee
Anaerobic oxidation of methane (AOM) is an important process for understanding the global flux of methane and its relation to the global carbon cycle. Although AOM is known to be coupled to reductions of sulfate, nitrite, and nitrate, evidence that AOM is coupled with extracellular electron transfer (EET) to conductive solids is relatively insufficient. Here, we demonstrate EET-dependent AOM in a biofilm anode dominated by Geobacter spp. and Methanobacterium spp. using carbon-fiber electrodes as the terminal electron sink...
July 11, 2017: Scientific Reports
Derek R Lovley
Direct interspecies electron transfer (DIET) has biogeochemical significance and practical applications that rely on DIET or DIET-based aspects of microbial physiology are growing. Mechanisms for DIET have primarily been studied in defined cocultures in which Geobacter species are one of the DIET partners. Electrically conductive pili (e-pili) can be an important electrical conduit for DIET. However, there may be instances in which electrical contacts are made between electron transport proteins associated with the outer membranes of the partners...
July 11, 2017: Annual Review of Microbiology
Enza Palma, Matteo Daghio, Andrea Franzetti, Marco Petrangeli Papini, Federico Aulenta
Groundwater contamination by petroleum hydrocarbons (PHs) is a widespread problem which poses serious environmental and health concerns. Recently, microbial electrochemical technologies (MET) have attracted considerable attention for remediation applications, having the potential to overcome some of the limiting factors of conventional in situ bioremediation systems. So far, field-scale application of MET has been largely hindered by the limited availability of scalable system configurations. Here, we describe the 'bioelectric well' a bioelectrochemical reactor configuration, which can be installed directly within groundwater wells and can be applied for in situ treatment of organic contaminants, such as PHs...
July 11, 2017: Microbial Biotechnology
Roman Moscoviz, Eric Trably, Nicolas Bernet
Electro-fermentation is a new technique that could be used to influence the global metabolism in mixed-culture fermentation. In this study, a mixed-culture cathodic electro-fermentation of glycerol was investigated. Both microbial community structure and metabolic patterns were altered when compared to standard fermentation. This microbial population shift was more significant when the working electrodes were pre-colonized by Geobacter sulfurreducens, before electro-fermentation. The electro-fermenting microbial community was more efficient for producing 1,3-propanediol with an improved yield of 10% when compared with fermentation controls...
July 11, 2017: Microbial Biotechnology
Junfeng Wang, Xinshan Song, Yuhui Wang, Junhong Bai, Manjie Li, Guoqiang Dong, Fanda Lin, Yanfeng Lv, Denghua Yan
Rhizodeposits excreted by various macrophytes might lead to the potential discrepancy of microbial community distribution in constructed wetland coupled with microbial fuel cell (CW-MFC), which has been considered as main factors for the variations of bioelectricity generation during wastewater treatment. In this study, CW-MFC has been associated with three macrophytes (J. effuses, T. orientalis and S. validus) for domestic sewage treatment, also unplanted CW-MFC was performed as a control system. Macrophyte T...
July 4, 2017: Science of the Total Environment
Chi Ho Chan, Caleb E Levar, Fernanda Jiménez-Otero, Daniel R Bond
Geobacter sulfurreducens generates electrical current by coupling intracellular oxidation of organic acids to reduction of proteins on the cell surface that are able to interface with electrodes. This ability is attributed to the bacterium's capacity to respire other extracellular electron acceptors that require contact, such as insoluble metal oxides. To directly investigate the genetic basis of electrode-based respiration, we constructed Geobacter sulfurreducens transposon-insertion sequencing (Tn-Seq) libraries for growth with soluble fumarate or an electrode as the electron acceptor...
July 3, 2017: Journal of Bacteriology
Yi-Nan Liu, Feng Zhang, Jie Li, Dao-Bo Li, Dong-Feng Liu, Wen-Wei Li, Han-Qing Yu
Azo dyes are a class of recalcitrant organic pollutants causing severe environmental pollution. For their biodecolorization, the azo reductase system was considered as the major molecular basis in bacteria. However, the intracellular localization of azo reductase limits their function for efficient azo dye decolorization. This limitation may be circumvented by electrochemically active bacteria (EAB) which is capable of extracellular respiration. To verify the essential role of extracellular respiration in azo dye decolorization, Geobacter sulfurreducens PCA, a model EAB, was used for the bioreduction of methyl orange (MO), a typical azo dye...
July 3, 2017: Environmental Science & Technology
Nweze Julius Eyiuche, Shiho Asakawa, Takahiro Yamashita, Atsuo Ikeguchi, Yutaka Kitamura, Hiroshi Yokoyama
BACKGROUND: The flame-oxidized stainless steel anode (FO-SSA) is a newly developed electrode that enhances microbial fuel cell (MFC) power generation; however, substrate preference and community structure of the biofilm developed on FO-SSA have not been well characterized. Herein, we investigated the community on FO-SSA using high-throughput sequencing of the 16S rRNA gene fragment in acetate-, starch-, glucose-, and livestock wastewater-fed MFCs. Furthermore, to analyze the effect of the anode material, the acetate-fed community formed on a common carbon-based electrode-carbon-cloth anode (CCA)-was examined for comparison...
June 29, 2017: BMC Microbiology
Shun'ichi Ishii, Shino Suzuki, Yuko Yamanaka, Angela Wu, Kenneth H Nealson, Orianna Bretschger
Microbial fuel cells (MFCs) are one of the bioelectrochemical systems that exploit microorganisms as biocatalysts to degrade organic matters and recover energy as electric power. Here, we explored how the established electrogenic microbial communities were influenced by three different inoculum sources; anaerobic sludge of the wastewater plant, rice paddy field soil, and coastal lagoon sediment. We periodically characterized both electricity generation with sucrose consumption and 16S rRNA-basis microbial community composition...
June 15, 2017: Bioelectrochemistry
Qian Liu, Bingfeng Liu, Wei Li, Xin Zhao, Wenjing Zuo, Defeng Xing
The performance of microbial electrochemical cells depends upon microbial community structure and metabolic activity of the electrode biofilms. Iron as a signal affects biofilm development and enrichment of exoelectrogenic bacteria. In this study, the effect of ferrous iron on microbial communities of the electrode biofilms in microbial fuel cells (MFCs) was investigated. Voltage production showed that ferrous iron of 100 μM facilitated MFC start-up compared to 150 μM, 200 μM, and without supplement of ferrous iron...
2017: Frontiers in Microbiology
Yaohuan Gao, Hodon Ryu, Bruce E Rittmann, Abid Hussain, Hyung-Sool Lee
A biofilm anode acclimated with growth media containing acetate, then acetate+methane, and finally methane alone produced electrical current in a microbial electrochemical cell (MxC) fed with methane as the sole electron donor. Geobacter was the dominant genus for the bacterial domain (93%) in the biofilm anode, while methanogens (Methanocorpusculum labreanum and Methanosaeta concilii) accounted for 82% of the total archaeal clones in the biofilm. Fluorescence in situ hybridization (FISH) imaging clearly showed a biofilm of mixed bacteria and archaea, suggesting a syntrophic interaction between them for performing anaerobic oxidation of methane (AOM) in the biofilm anode...
October 2017: Bioresource Technology
Tomo Aoyagi, Hideaki Koike, Tomotake Morita, Yuya Sato, Hiroshi Habe, Tomoyuki Hori
Here, we report a draft genome sequence of Geobacter pelophilus strain Dfr2, a ferric iron-reducing bacterium. This genome information will further our understanding of the mechanisms underlying electron transfer from microorganisms to ferric iron oxides.
June 15, 2017: Genome Announcements
Clara Corbella, Rebecca P Steidl, Jaume Puigagut, Gemma Reguera
Power generation in microbial fuel cells implemented in constructed wetlands (CW-MFCs) is low despite the enrichment of anode electricigens most closely related to Geobacter lovleyi. Using the model representative G. lovleyi strain SZ, we show that acetate, but not formate or lactate, can be oxidized efficiently but growth is limited by the high sensitivity of the bacterium to oxygen. Acetate and highly reducing conditions also supported the growth of anode biofilms but only at optimal anode potentials (450 mV vs...
June 2017: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Xiaoxue Mei, Defeng Xing, Yang Yang, Qian Liu, Huihui Zhou, Changhong Guo, Nanqi Ren
Temperature as an important ecological factor affects biofilm development and microbial metabolic activity. Here, the performances and microbial communities of microbial fuel cells (MFCs) at different temperature were analyzed. As the temperature decreased, the power output of MFCs declined. A maximum power density of 894.3±48.6mW/m(2) was obtained in MFCs operating at 30°C, which was 18.5% and 64.5% higher than that in MFCs at 20°C and 10°C, respectively. Illumina sequencing of 16S rRNA gene amplicons showed that a distinct difference in microbial community structure of the anode biofilms occurred...
May 24, 2017: Bioelectrochemistry
Junfeng Chen, Lihua Zhang, Yongyou Hu, Wantang Huang, Zhuyu Niu, Jian Sun
In this work, bacterial community shift and incurred performance of graphene modified bioelectrode (GM-BE) in microbial fuel cell (MFC) were illustrated by high throughput sequencing technology and electrochemical analysis. The results showed that Firmicutes occupied 48.75% in graphene modified bioanode (GM-BA), while Proteobacteria occupied 62.99% in graphene modified biocathode (GM-BC), both were dominant bacteria in phylum level respectively. Typical exoelectrogens, including Geobacter, Clostridium, Pseudomonas, Geothrix and Hydrogenophaga, were counted 26...
October 2017: Bioresource Technology
Richen Lin, Jun Cheng, Jiabei Zhang, Junhu Zhou, Kefa Cen, Jerry D Murphy
Interspecies electron transfer between bacteria and archaea plays a vital role in enhancing energy efficiency of anaerobic digestion (AD). Conductive carbon materials (i.e. graphene nanomaterial and activated charcoal) were assessed to enhance AD of ethanol (a key intermediate product after acidogenesis of algae). The addition of graphene (1.0g/L) resulted in the highest biomethane yield (695.0±9.1mL/g) and production rate (95.7±7.6mL/g/d), corresponding to an enhancement of 25.0% in biomethane yield and 19...
September 2017: Bioresource Technology
Michael J McAnulty, Venkata G Poosarla, Kyoung-Yeol Kim, Ricardo Jasso-Chávez, Bruce E Logan, Thomas K Wood
Given our vast methane reserves and the difficulty in transporting methane without substantial leaks, the conversion of methane directly into electricity would be beneficial. Microbial fuel cells harness electrical power from a wide variety of substrates through biological means; however, the greenhouse gas methane has not been used with much success previously as a substrate in microbial fuel cells to generate electrical current. Here we construct a synthetic consortium consisting of: (i) an engineered archaeal strain to produce methyl-coenzyme M reductase from unculturable anaerobic methanotrophs for capturing methane and secreting acetate; (ii) micro-organisms from methane-acclimated sludge (including Paracoccus denitrificans) to facilitate electron transfer by providing electron shuttles (confirmed by replacing the sludge with humic acids), and (iii) Geobacter sulfurreducens to produce electrons from acetate, to create a microbial fuel cell that converts methane directly into significant electrical current...
May 17, 2017: Nature Communications
Eveline M van den Berg, Julius L Rombouts, J Gijs Kuenen, Robbert Kleerebezem, Mark C M van Loosdrecht
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two microbial processes that compete for oxidized nitrogen compounds in the environment. The objective of this work was to determine the role of nitrite versus nitrate as terminal electron acceptor on the competition between DNRA and denitrification. Initially, a mixed culture chemostat was operated under nitrate limitation and performed DNRA. Stepwise, the influent nitrate was replaced with nitrite until nitrite was the sole electron acceptor and N-source present...
December 2017: AMB Express
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