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https://www.readbyqxmd.com/read/28443365/enhanced-phosphorus-reduction-in-simulated-eutrophic-water-a-comparative-study-of-submerged-macrophytes-sediment-microbial-fuel-cells-and-their-combination
#1
Peng Xu, Enrong Xiao, Dan Xu, Juan Li, Yi Zhang, Zhigang Dai, Qiaohong Zhou, Zhenbin Wu
The phosphorus content reduction in overlying and sediment pore water was attempted by integrating sediment microbial fuel cells (SMFCs) with the submerged macrophyte Vallisneria spiralis. A comparative study was conducted to treat simulated water rich in phosphate with a control and three treatments: SMFC alone (SMFC), submerged macrophytes alone (macophyte), and combined macrophytes and fuel cells (M-SMFC). All treatments increased sediment Eh and pH of the overlying water, thus promoting phosphorus flux from water column to sediments...
April 26, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28442658/predominant-but-previously-overlooked-prokaryotic-drivers-of-reductive-nitrogen-transformation-in-paddy-soils-revealed-by-metatranscriptomics
#2
Yoko Masuda, Hideomi Itoh, Yutaka Shiratori, Kazuo Isobe, Shigeto Otsuka, Keishi Senoo
Waterlogged paddy soils possess anoxic zones in which microbes actively induce reductive nitrogen transformation (RNT). In the present study, a shotgun RNA sequencing analysis (metatranscriptomics) of paddy soil samples revealed that most RNT gene transcripts in paddy soils were derived from Deltaproteobacteria, particularly the genera Anaeromyxobacter and Geobacter. Despite the frequent detection of the rRNA of these microbes in paddy soils, their RNT-associated genes have rarely been identified in previous PCR-based studies...
April 22, 2017: Microbes and Environments
https://www.readbyqxmd.com/read/28431359/reconstruction-of-microbial-community-structures-as-evidences-for-soil-redox-coupled-reductive-dechlorination-of-pcp-in-a-mangrove-soil
#3
Yan Xu, Yan He, Xianjin Tang, Philip C Brookes, Jianming Xu
The aim was to investigate the influence of pentachlorophenol (PCP) on the soil microbial communities and the coupled mechanism between PCP reductive dechlorination and soil redox under anaerobic condition. Accordingly, a slurry incubation experiment was carried out in which bacterial and archaeal communities were detected by MiSeq amplicon sequencing. The original microbial community balance was gradually disrupted and new microbial structure was reconstructed subsequently through self-regulation and acclimation during PCP transformation, coupling with the changes of soil biogeochemical redox dynamics...
April 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28429471/formation-of-silver-nanoparticles-by-electron-transfer-in-peptides-and-c-cytochromes
#4
Serhii I Vasylevskyi, Sonja Kracht, Paula Corcosa, Katharina M Fromm, Bernd Giese, Michael Füeg
The reduction of Ag(+) ions to Ag(0) atoms is a highly endergonic reaction step, only the aggregation to Agn clusters leads to an exergonic process. These elementary chemical reactions play a decisive role if Ag nanoparticles (AgNPs) are generated by electron transfer (ET) reactions to Ag(+) ions. We studied the formation of AgNPs in peptides by photoinduced ET, and in c-cytochromes by ET from their Fe(2+) /hemes. Our earlier photoinduced experiments in peptides had demonstrated that histidine prevents AgNP formation...
April 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28402361/electronic-characterization-of-geobacter-sulfurreducens-pilins-in-self-assembled-monolayers-unmasks-tunnelling-and-hopping-conduction-pathways
#5
Krista M Cosert, Rebecca J Steidl, Angelines Castro-Forero, Robert M Worden, Gemma Reguera
The metal-reducing bacterium Geobacter sulfurreducens produces protein nanowires (pili) for fast discharge of respiratory electrons to extracellular electron acceptors such as iron oxides and uranium. Charge transport along the pili requires aromatic residues, which cluster once the peptide subunits (pilins) assemble keeping inter-aromic distances and geometries optimal for multistep hopping. The presence of intramolecular aromatic contacts and the predominantly α-helical conformation of the pilins has been proposed to contribute to charge transport and rectification...
April 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28401700/silica-immobilization-of-geobacter-sulfurreducens-for-constructing-ready-to-use-artificial-bioelectrodes
#6
Marta Estevez-Canales, David Pinto, Thibaud Coradin, Christel Laberty-Robert, Abraham Esteve-Núñez
Microbial electrochemical technologies (METs) rely on the control of interactions between microorganisms and electronic devices, enabling to transform chemical energy into electricity. We report a new approach to construct ready-to-use artificial bioelectrodes by immobilizing Geobacter sulfurreducens cells in composite materials associating silica gel and carbon felt fibres. Viability test confirmed that the majority of bacteria (ca. 70 ± 5%) survived the encapsulation process in silica and that cell density did not increase in 96 h...
April 11, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28391101/control-of-vocs-from-printing-press-air-emissions-by-anaerobic-bioscrubber-performance-and-microbial-community-of-an-on-site-pilot-unit
#7
D Bravo, P Ferrero, J M Penya-Roja, F J Álvarez-Hornos, C Gabaldón
A novel process consisted of an anaerobic bioscrubber was studied at the field scale for the removal of volatile organic compounds (VOCs) emitted from a printing press facility. The pilot unit worked under high fluctuating waste gas emissions containing ethanol, ethyl acetate, and 1-ethoxy-2-propanol as main pollutants, with airflows ranging between 184 and 1253 m(3) h(-1) and an average concentration of 1126 ± 470 mg-C Nm(-3). Three scrubber configurations (cross-flow and vertical-flow packings and spray tower) were tested, and cross-flow packing was found to be the best one...
April 6, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28377068/solution-structure-and-dynamics-of-the-outer-membrane-cytochrome-omcf-from-geobacter-sulfurreducens
#8
Joana M Dantas, Marta A Silva, David Pantoja-Uceda, David L Turner, Marta Bruix, Carlos A Salgueiro
Gene knock-out studies on Geobacter sulfurreducens cells showed that the outer membrane-associated monoheme cytochrome OmcF is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI). In addition, microarray analysis of an OmcF-deficient mutant revealed that many of the genes with decreased transcript level were those whose expression is up-regulated in cells grown with a graphite electrode as electron acceptor, suggesting that OmcF also regulates the electron transfer to electrode surfaces and the concomitant electricity production by G...
April 1, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28374997/ecological-and-transcriptional-responses-of-anode-respiring-communities-to-nitrate-in-a-microbial-fuel-cell
#9
Varun N Srinivasan, Caitlyn S Butler
A poorly understood phenomenon with a potentially significant impact on electron recovery is competition in microbial fuel cells (MFC) between anode-respiring bacteria and microorganisms that use other electron acceptors. Nitrate is a constituent of different wastewaters and can act as a competing electron acceptor in the anode. Studies investigating the impact of competition on population dynamics in mixed communities in the anode are lacking. Here, we investigated the impact of nitrate at different C/N ratios of 1...
April 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28362850/chemical-property-based-sequence-characterization-of-ppca-and-its-homolog-proteins-ppcb-e-a-mathematical-approach
#10
Jayanta Kumar Das, Pabitra Pal Choudhury
Periplasmic c7 type cytochrome A (PpcA) protein is determined in Geobacter sulfurreducens along with its other four homologs (PpcB-E). From the crystal structure viewpoint the observation emerges that PpcA protein can bind with Deoxycholate (DXCA), while its other homologs do not. But it is yet to be established with certainty the reason behind this from primary protein sequence information. This study is primarily based on primary protein sequence analysis through the chemical basis of embedded amino acids...
2017: PloS One
https://www.readbyqxmd.com/read/28348867/the-electrically-conductive-pili-of-geobacter-species-are-a-recently-evolved-feature-for-extracellular-electron-transfer
#11
Dawn E Holmes, Yan Dang, David J F Walker, Derek R Lovley
The electrically conductive pili (e-pili) of Geobactersulfurreducens have environmental and practical significance because they can facilitate electron transfer to insoluble Fe(III) oxides; to other microbial species; and through electrically conductive biofilms. E-pili conductivity has been attributed to the truncated PilA monomer, which permits tight packing of aromatic amino acids to form a conductive path along the length of e-pili. In order to better understand the evolution and distribution of e-pili in the microbial world, type IVa PilA proteins from various Gram-negative and Gram-positive bacteria were examined with a particular emphasis on Fe(III)-respiring bacteria...
August 2016: Microbial Genomics
https://www.readbyqxmd.com/read/28341095/nano-graphene-induced-positive-effects-on-methanogenesis-in-anaerobic-digestion
#12
Tian Tian, Sen Qiao, Xue Li, Meijiao Zhang, Jiti Zhou
The effects of nano-graphene on methanogenesis in anaerobic digestion was investigated. Short-term results showed that graphene (30 and 120mg/L) had significantly positive effects on methane production rate, which increased by 17.0% and 51.4%. Further investigation indicated that acetate-consuming methanogenesis was enhanced. The failure of quinones to replicate graphene stimulation effects on methanogenesis suggested that graphene did not function as electron shuttles. After 55 day's operation at room temperature (from 20 to 10°C, the methane production rate with 30mg/L graphene was 14...
January 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28340434/potentially-direct-interspecies-electron-transfer-of-methanogenesis-for-syntrophic-metabolism-under-sulfate-reducing-conditions-with-stainless-steel
#13
Yue Li, Yaobin Zhang, Yafei Yang, Xie Quan, Zhiqiang Zhao
Direct interspecies electron transfer (DIET) is an alternative to syntrophic metabolism in natural carbon cycle as well as in anaerobic digesters, but its function in anaerobic treatment of sulfate-containing wastewater have not yet to be described. Here, conductive stainless steel was added into anaerobic digesters for treating sulfate-containing wastewater to investigate the potential role of DIET in the response to the sulfate impact. Results showed that adding the conductive stainless steel made the anaerobic digestion less affected by the sulfate reduction than adding insulative plastic material...
March 12, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28337937/evaluation-of-methanogenic-microbial-electrolysis-cells-mecs-under-closed-open-circuit-operations
#14
Liwen Luo, Suyun Xu, Yueqing Jin, Runqi Han, Hongbo Liu, Fan Lü
This study investigated the independent roles of biofilm and external power supply for volatile fatty acids (VFAs) degradation and methane production in the microbial electrolysis cell (MEC). Reactors were operated in fed-batch mode in the presence of graphite felt(GF) or titanium-rod (Ti) as electrodes, in open circuit (OC, without applied voltage) or closed circuit (CC) conditions, i.e. R1 (Ti+CC), R2 (GF+CC) and R3 (GF+OC). The first-order kinetic analysis of acetate degradation indicated that the presence of GF biofilm and applied voltage in R2 improved the acetate degradation rate by 23% as compared to R1, while it was only 7% increment in R3 with GF biofilm...
March 24, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28330093/exploration-of-nifh-gene-through-soil-metagenomes-of-the-western-indian-himalayas
#15
Ravindra Soni, Deep Chandra Suyal, Santosh Sai, Reeta Goel
This group has previously highlighted the prevalence of Csp genes from cold Himalayan environments. However, this study has explored the uncultured diazotrophs from metagenomes of western Indian Himalayas. The metagenomic nifH gene clone library was constructed from the Temperate, Subtropical and Tarai soils of Western Himalaya, India followed by polymerase chain reaction (PCR) amplification. After preliminary screening, selected clones were sequenced. In silico analysis of the clones was done, which documented 83...
June 2016: 3 Biotech
https://www.readbyqxmd.com/read/28295106/structure-electrocatalysis-and-dynamics-of-immobilized-cytochrome-pcch-and-its-microperoxidase
#16
Célia M Silveira, María A Castro, Joana M Dantas, Carlos Salgueiro, Daniel H Murgida, Smilja Todorovic
Geobacter sulfurreducens cells have the ability to exchange electrons with conductive materials, and the periplasmic cytochrome PccH plays an essential role in the direct electrode-to-cell electron transfer in this bacterium. It has atypically low redox potential and unique structural features that differ from those observed in other c-type cytochromes. We report surface enhanced resonance Raman spectroscopic and electrochemical characterization of the immobilized PccH, together with molecular dynamics simulations that allow for the rationalization of experimental observations...
March 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28287150/cooperative-growth-of-geobacter-sulfurreducens-and-clostridium-pasteurianum-with-subsequent-metabolic-shift-in-glycerol-fermentation
#17
Roman Moscoviz, Florence de Fouchécour, Gaëlle Santa-Catalina, Nicolas Bernet, Eric Trably
Interspecies electron transfer is a common way to couple metabolic energy balances between different species in mixed culture consortia. Direct interspecies electron transfer (DIET) mechanism has been recently characterised with Geobacter species which couple the electron balance with other species through physical contacts. Using this mechanism could be an efficient and cost-effective way to directly control redox balances in co-culture fermentation. The present study deals with a co-culture of Geobacter sulfurreducens and Clostridium pasteurianum during glycerol fermentation...
March 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28279910/response-of-microbial-community-structure-to-pre-acclimation-strategies-in-microbial-fuel-cells-for-domestic-wastewater-treatment
#18
Younghyun Park, Hyunwoo Cho, Jaechul Yu, Booki Min, Hong Suck Kim, Byung Goon Kim, Taeho Lee
Microbial community structures and performance of air-cathode microbial fuel cells (MFCs) inoculated with activated sludge from domestic wastewater were investigated to evaluate the effects of three substrate pre-acclimation strategies: 1, serial pre-acclimation with acetate and glucose before supplying domestic wastewater; 2, one step pre-acclimation with acetate before supplying domestic wastewater; and 3, direct supply of domestic wastewater without any pre-acclimation. Strategy 1 showed much higher current generation (1...
February 27, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28273578/polarity-inversion-of-bioanode-for-biocathodic-reduction-of-aromatic-pollutants
#19
Hui Yun, Bin Liang, De-Yong Kong, Hao-Yi Cheng, Zhi-Ling Li, Ya-Bing Gu, Hua-Qun Yin, Ai-Jie Wang
The enrichment of specific pollutant-reducing consortium is usually required prior to the startup of biocathode bioelectrochemical system (BES) and the whole process is time consuming. To rapidly establish a non-specific functional biocathode, direct polar inversion from bioanode to biocathode is proposed in this study. Based on the diverse reductases and electron transfer related proteins of anode-respiring bacteria (ARB), the acclimated electrochemically active biofilm (EAB) may catalyze reduction of different aromatic pollutants...
February 27, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28258137/metatranscriptomic-evidence-for-direct-interspecies-electron-transfer-between-geobacter-and-methanothrix-species-in-methanogenic-rice-paddy-soils
#20
Dawn E Holmes, Pravin M Shrestha, David J F Walker, Yan Dang, Kelly P Nevin, Trevor L Woodard, Derek R Lovley
The possibility that Methanothrix (formerly Methanosaeta) and Geobacter species cooperate via direct interspecies electron transfer (DIET) in terrestrial methanogenic environments was investigated in rice paddy soils. Genes with high sequence similarity to the gene for the PilA pilin monomer of the electrically conductive pili (e-pili) of Geobacter sulfurreducens accounted for over half of the PilA gene sequences in metagenomic libraries and 42% of the mRNA transcripts in RNA sequencing (RNA-seq) libraries...
May 1, 2017: Applied and Environmental Microbiology
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