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Soroush Saheb-Alam, Abhijeet Singh, Malte Hermansson, Frank Persson, Anna Schnürer, Britt-Marie Wilén, Oskar Modin
The enrichment of CO2-reducing microbial bio-cathodes is challenging. Previous research has shown that a promising approach could be to first enrich bio-anodes and then lower the potential so the electrodes are converted into bio-cathodes. However, the effect of such a transition on the microbial community on the electrode has not been studied. The goal of this study was, thus, to compare the start-up of bio-cathodes from pre-enriched anodes with direct start-up from bare electrodes and to investigate changes in microbial community composition...
December 8, 2017: Applied and Environmental Microbiology
Clara Vieira de Faria, Tiago Palladino Delforno, Dagoberto Yukio Okada, Maria Bernadete Amâncio Varesche
An expanded granular sludge bed (EGSB) reactor was evaluated for the anaerobic digestion of commercial laundry wastewater and domestic sewage focused on the removal of linear alkylbenzene sulfonate (LAS). The reactor was operated in three stages, all under mesophilic conditions and with a hydraulic retention time (HRT) of 36 hours. At stage I, the laundry wastewater was diluted with tap water (influent: 15.3 ± 4.9 mg LAS/L); at stage II, 50% of the feed volume was domestic sewage and 50% was a mixture of tap water and laundry wastewater (influent: 15...
December 6, 2017: Environmental Technology
Jiang-Tao Qiao, Xiao-Min Li, Fang-Bai Li
Although biochar has great potential for heavy metal removal from sediments or soils, its impact on arsenic biogeochemistry in contaminated paddy fields remains poorly characterized. In this study, anaerobic microcosms were established with arsenic-contaminated paddy soil to investigate arsenic transformation as well as the potentially active microbial community and their transcriptional activities in the presence of biochar. The results demonstrated that biochar can simultaneously stimulate microbial reduction of As(V) and Fe(III), releasing high levels of As(III) into the soil solution relative to the control...
November 21, 2017: Journal of Hazardous Materials
Jiangtao Qiao, Xiaomin Li, Min Hu, Fangbai Li, Lily Y Young, Weimin Sun, Weilin Huang, Jianghu Cui
Organic substrates and biochar are important in controlling arsenic release from sediments and soils, however, little is known about their impacts on arsenic-reducing bacteria and genes during arsenic transformation in flooded paddy soils. In this study, microcosm experiments were established to profile transcriptional activity of As(V)-respiring gene (arrA) and arsenic resistance gene (arsC) as well as the associated bacteria regulated by lactate and/or biochar in anaerobic arsenic-contaminated paddy soils...
November 30, 2017: Environmental Science & Technology
Ji-Hoon Lee, Bong-Joo Lee
Agricultural demands continuously increased use of groundwater, causing drawdown of water table and need of artificial recharge using adjacent stream waters. River water intrusion into groundwater can alter the geochemical and microbiological characteristics in the aquifer and subsurface. In an effort to investigate the subsurface biogeochemical activities before operation of artificial recharge at the test site, established at the bank of Nakdong River, Changwon, South Korea, organic carbon transported from river water to groundwater was mimicked and the effect on the indigenous microbial communities was investigated with the microcosm incubations of the groundwater and subsurface sediments...
November 25, 2017: Microbial Ecology
Van Khanh Nguyen, Wonyoung Choi, Younghyun Park, Jaecheul Yu, Taeho Lee
This study aims to enrich Sb(V)-reducing bacterial communities from Sb-contaminated soils using various electron donors for bioremediation of Sb-contaminated sites and recovery of Sb from wastewater. When the organic electron donors were used, Sb(V) reduction rates were 2-24 times faster but electron recoveries were 24-59% lower compared to the culture using inorganic electron donor. The morphological crystallizations of the antimony-reduced precipitates were completely different depending on the electron donor...
November 22, 2017: Bioresource Technology
Irina V Khilyas, Anatoly A Sorokin, Larisa Kiseleva, David J W Simpson, V Fedorovich, Margarita R Sharipova, Mami Kainuma, Michael F Cohen, Igor Goryanin
Bioelectrochemical systems such as microbial fuel cells (MFCs) are promising new technologies for efficient removal of organic compounds from industrial wastewaters, including that generated from swine farming. We inoculated two pairs of laboratory-scale MFCs with sludge granules from a beer wastewater-treating anaerobic digester (IGBS) or from sludge taken from the bottom of a tank receiving swine wastewater (SS). The SS-inoculated MFC outperformed the IGBS-inoculated MFC with regard to COD and VFA removal and electricity production...
2017: Scientifica
Lu Wang, Yulei Liu, Chao Wang, Xiaodan Zhao, Gurumurthy Dummi Mahadeva, Yicheng Wu, Jun Ma, Feng Zhao
Triclosan (TCS) is an emerging organic contaminant in the environment. Here, the anoxic bio-degradation of TCS in microbial fuel cells (MFCs) was explored. It was found that anoxic biodegradation of TCS could be achieved in MFC, and the removal rate of TCS was accelerated after reactor acclimation. After 7 months of operation, 10mg/L TCS could be removed within 8days in MFCs. Fluorescence microscopy results revealed that the microbe cells in the reactors were intact, and the microbes were in active state. Flow cytometry test showed that the proliferation of inoculated microbe was higher in MFC effluent than that in TCS solution...
October 13, 2017: Journal of Hazardous Materials
Laura Rago, Sarah Zecchin, Stefania Marzorati, Andrea Goglio, Lucia Cavalca, Pierangela Cristiani, Andrea Schievano
Recently, terracotta has attracted interest as low-cost and biocompatible material to build separators in microbial fuel cells (MFCs). However, the influence of a non-conductive material like terracotta on electroactive microbiological communities remains substantially unexplored. This study aims at describing the microbial pools developed from two different seed inocula (bovine and swine sewage) in terracotta-based air-breathing MFC. A statistical approach on microbiological data confirmed different community enrichment in the MFCs, depending mainly on the inoculum...
November 11, 2017: Bioelectrochemistry
Brodie Sutcliffe, Anthony A Chariton, Andrew J Harford, Grant C Hose, Sarah Stephenson, Paul Greenfield, David J Midgley, Ian T Paulsen
Elevated uranium dose (4 g kg(-1)) causes a shift in billabong sediment communities that result in the enrichment of five bacterial species. These taxa include Geobacter, Geothrix and Dyella species, as well as a novel-potentially predatory-Bacteroidetes species, and a new member of class Anaerolineae (Chloroflexi). Additionally, a population of methanogenic Methanocella species was also identified. Genomic reconstruction and metabolic examination of these taxa reveal a host of divergent life strategies and putative niche partitioning...
November 11, 2017: Microbial Ecology
Yanping Bao, Chuling Guo, Guining Lu, Xiaoyun Yi, Han Wang, Zhi Dang
Fe(III) hydroxysulfate minerals are secondary minerals commonly found in acid mine drainage (AMD) sites and have a major impact on water and soil quality in these environments. While previous studies showed that the Fe(III) hydroxysulfate mineral transformation could be mediated by some bacterial strains under laboratory conditions, the role of indigenous microbial activity in Fe(III) hydroxysulfate mineral transformation in natural environment has received little attention. In this study, microcosms were constructed with AMD-affected river water and sediment from the Dabaoshan Mine that was either left unamended or enriched with nutrients (lactate, nitrogen, and phosphorus (LNP)) and biosynthetic minerals (schwertmannite or jarosite)...
November 2, 2017: Science of the Total Environment
Shiling Zheng, Fanghua Liu, Meng Li, Leilei Xiao, Oumei Wang
Both activated carbon and magnetite have been reported to promote the syntrophic growth of Geobacter metallireducens and Geobacter sulfurreducens co-cultures, the first model to show direct interspecies electron transfer (DIET); however, differential transcriptomics of the promotion on co-cultures with these two conductive materials are unknown. Here, the comparative transcriptomic analysis of G. metallireducens and G. sulfurreducens co-cultures with granular activated carbon (GAC) and magnetite was reported...
October 31, 2017: Science China. Life Sciences
Manoj Kumar, Jan Dirk van Elsas, Riitta Nissinen
Arctic and alpine biomes are most often strongly nitrogen-limited, and hence biological nitrogen fixation is a strong driver of these ecosystems. Both biomes are characterized by low temperatures and short growing seasons, but they differ in seasonality of solar radiation and in soil water balance due to underlying permafrost in the Arctic. Arcto-alpine plant species are well-adapted to the low temperatures that prevail in their habitats, and plant growth is mainly limited by the availability of nutrients, in particular nitrogen, due to slow mineralization...
2017: Frontiers in Microbiology
Cheng Li, Keaton Larson Lesnik, Hong Liu
Extracellular electron transfer between syntrophic partners needs to be efficiently maintained in methanogenic environments. Direct extracellular electron transfer via electrical current is an alternative to indirect hydrogen transfer but requires construction of conductive extracellular structures. Conductive mechanisms and relationship between conductivity and the community composition in mixed-species methanogenic biofilms are not well understood. The present study investigated conductive behaviors of methanogenic biofilms and examined the correlation between biofilm conductivity and community composition between different anaerobic biofilms enriched from the same inoculum...
October 19, 2017: Bioelectrochemistry
Huihui Zhou, Bingfeng Liu, Qisong Wang, Jianmin Sun, Guojun Xie, Nanqi Ren, Zhiyong Jason Ren, Defeng Xing
BACKGROUND: Microbial extracellular electron transfer (EET) is essential in driving the microbial interspecies interaction and redox reactions in bioelectrochemical systems (BESs). Magnetite (Fe3O4) and magnetic fields (MFs) were recently reported to promote microbial EET, but the mechanisms of MFs stimulation of EET and current generation in BESs are not known. This study investigates the behavior of current generation and EET in a state-of-the-art pulse electromagnetic field (PEMF)-assisted magnetic BES (PEMF-MBES), which was equipped with magnetic carbon particle (Fe3O4@N-mC)-coated electrodes...
2017: Biotechnology for Biofuels
Francesca Simonte, Gunnar Sturm, Johannes Gescher, Katrin Sturm-Richter
This chapter summarizes in the beginning our current understanding of extracellular electron transport processes in organisms belonging to the genera Shewanella and Geobacter. Organisms belonging to these genera developed strategies to transport respiratory electrons to the cell surface that are defined by modules of which some seem to be rather unique for one or the other genus while others are similar. We use this overview regarding our current knowledge of extracellular electron transfer to explain the physiological interaction of microorganisms in direct interspecies electron transfer, a process in which one organism basically comprises the electron acceptor for another microbe and that depends also on extended electron transport chains...
October 26, 2017: Advances in Biochemical Engineering/biotechnology
R M Alonso, M I San-Martín, A Sotres, A Escapa
This study seeks to assess the impact that the anodic electrodeposition of graphene oxide (GO) has on the start-up process and on the development of microbial communities on the anode of BESs. The GO electrodeposited electrodes were characterised in abiotic conditions to verify the extent of the modification and were then transferred to a bioelectrochemical reactor. Results showed that the modified electrode allowed for a reduced start-up time compared to the control electrode. After three months, high throughput sequencing was performed, revealing that electrochemically reduced graphene oxide acts as a selective agent toward exoelectrogenic bacteria as Geobacter...
October 23, 2017: Scientific Reports
Bipro Ranjan Dhar, Junyoung Sim, Hodon Ryu, Hao Ren, Jorge W Santo Domingo, Junseok Chae, Hyung-Sool Lee
This study assessed the conductivity of a Geobacter-enriched biofilm anode in a microbial electrochemical cell (MxC) equipped with two gold anodes (25 mM acetate medium), as different proton gradients were built throughout the biofilm. There was no pH gradient across the biofilm anode at 100 mM phosphate buffer (current density 2.38 A/m(2)) and biofilm conductivity (Kbio) was as high as 0.87 mS/cm. In comparison, an inner biofilm became acidic at 2.5 mM phosphate buffer in which dead cells were accumulated at ∼80 μm of the inner biofilm anode...
October 13, 2017: Water Research
Lucie Semenec, Andrew E Laloo, Benjamin L Schulz, Ismael A Vergara, Philip L Bond, Ashley E Franks
Interspecies electron transfer (IET) occurs in many microbial communities, enabling extracellular electron exchange for syntrophic utilization of mixed resources. Various mechanisms of IET have been characterized including direct IET (DIET) and hydrogen IET (HIT) but their evolution throughout syntrophic adaptation has not been investigated through an omics approach. A syntrophic coculture of Geobacter sulfurreducens and Pseudomonas aeruginosa was established and evolved in restricted medium. The medium required cooperative metabolism due to preferential utilization of formate and fumarate by P...
October 3, 2017: Bioelectrochemistry
Matthew D Yates, Brian J Eddie, Nikolai Lebedev, Nicholas J Kotloski, Sarah M Strycharz-Glaven, Leonard M Tender
The ability of certain microorganisms to live in a multi-cell thick, electrode-grown biofilm by utilizing the electrode as a metabolic electron acceptor or donor requires electron transfer across cell membranes, through the biofilm, and across the biofilm/electrode interface. Even for the most studied system, anode-grown Geobacter sulfurreducens, the mechanisms underpinning each process and how they connect is largely unresolved. Here we report on G. sulfurreducens biofilms grown across the gap separating two electrodes by maintaining one electrode at 0...
September 18, 2017: Bioelectrochemistry
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