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Sample records for metabolism microbial cell

  1. Kinetic modeling of cell metabolism for microbial production.

    Costa, Rafael S; Hartmann, Andras; Vinga, Susana

    2016-02-10

    Kinetic models of cellular metabolism are important tools for the rational design of metabolic engineering strategies and to explain properties of complex biological systems. The recent developments in high-throughput experimental data are leading to new computational approaches for building kinetic models of metabolism. Herein, we briefly survey the available databases, standards and software tools that can be applied for kinetic models of metabolism. In addition, we give an overview about recently developed ordinary differential equations (ODE)-based kinetic models of metabolism and some of the main applications of such models are illustrated in guiding metabolic engineering design. Finally, we review the kinetic modeling approaches of large-scale networks that are emerging, discussing their main advantages, challenges and limitations. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Microbial Metabolism in Serpentinite Fluids

    Crespo-Medina, M.; Brazelton, W. J.; Twing, K. I.; Kubo, M.; Hoehler, T. M.; Schrenk, M. O.

    2013-12-01

    Serpentinization is the process in which ultramafic rocks, characteristic of the upper mantle, react with water liberating mantle carbon and reducing power to potenially support chemosynthetic microbial communities. These communities may be important mediators of carbon and energy exchange between the deep Earth and the surface biosphere. Our work focuses on the Coast Range Ophiolite Microbial Observatory (CROMO) in Northern California where subsurface fluids are accessible through a series of wells. Preliminary analyses indicate that the highly basic fluids (pH 9-12) have low microbial diversity, but there is limited knowledge about the metabolic capabilities of these communties. Metagenomic data from similar serpentine environments [1] have identified Betaproteobacteria belonging to the order Burkholderiales and Gram-positive bacteria from the order Clostridiales as key components of the serpentine microbiome. In an effort to better characterize the microbial community, metabolism, and geochemistry at CROMO, fluids from two representative wells (N08B and CSWold) were sampled during recent field campaigns. Geochemical characterization of the fluids includes measurements of dissolved gases (H2, CO, CH4), dissolved inorganic and organic carbon, volatile fatty acids, and nutrients. The wells selected can be differentiated in that N08B had higher pH (10-11), lower dissolved oxygen, and cell counts ranging from 105-106 cells mL-1 of fluid, with an abundance of the betaproteobacterium Hydrogenophaga. In contrast, fluids from CSWold have slightly lower pH (9-9.5), DO, and conductivity, as well as higher TDN and TDP. CSWold fluid is also characterized for having lower cell counts (~103 cells mL-1) and an abundance of Dethiobacter, a taxon within the phylum Clostridiales. Microcosm experiments were conducted with the purpose of monitoring carbon fixation, methanotrophy and metabolism of small organic compounds, such as acetate and formate, while tracing changes in fluid

  3. New transposon tools tailored for metabolic engineering of Gram-negative microbial cell factories

    Esteban eMartínez-García

    2014-10-01

    Full Text Available Re-programming microorganisms to modify their existing functions and/or to bestow bacteria with entirely new-to-Nature tasks have largely relied so far on specialized molecular biology tools. Such endeavors are not only relevant in the burgeoning metabolic engineering arena, but also instrumental to explore the functioning of complex regulatory networks from a fundamental point of view. À la carte modification of bacterial genomes thus calls for novel tools to make genetic manipulations easier. We propose the use of a series of new broad-host-range mini-Tn5 vectors, termed pBAMDs, for the delivery of gene(s into the chromosome of Gram-negative bacteria and for generating saturated mutagenesis libraries in gene function studies. These delivery vectors endow the user with the possibility of easy cloning and subsequent insertion of functional cargoes with three different antibiotic resistance markers (kanamycin, streptomycin, and gentamicin. After validating the pBAMD vectors in the environmental bacterium Pseudomonas putida KT2440, their use was also illustrated by inserting the entire poly(3-hydroxybutyrate (PHB synthesis pathway from Cupriavidus necator in the chromosome of a phosphotransacetylase mutant of Escherichia coli. PHB is a completely biodegradable polyester with a number of industrial applications that make it attractive as a potential replacement of oil-based plastics. The non-selective nature of chromosomal insertions of the biosynthetic genes was evidenced by a large landscape of PHB synthesis levels in independent clones. One clone was selected and further characterized as a microbial cell factory for PHB accumulation, and it achieved polymer accumulation levels comparable to those of a plasmid-bearing recombinant. Taken together, our results demonstrate that the new mini-Tn5 vectors can be used to confer interesting phenotypes in Gram-negative bacteria that would be very difficult to engineer through direct manipulation of the

  4. New Transposon Tools Tailored for Metabolic Engineering of Gram-Negative Microbial Cell Factories

    Martínez-García, Esteban; Aparicio, Tomás; Lorenzo, Víctor de; Nikel, Pablo I.

    2014-01-01

    Re-programming microorganisms to modify their existing functions and/or to bestow bacteria with entirely new-to-Nature tasks have largely relied so far on specialized molecular biology tools. Such endeavors are not only relevant in the burgeoning metabolic engineering arena but also instrumental to explore the functioning of complex regulatory networks from a fundamental point of view. À la carte modification of bacterial genomes thus calls for novel tools to make genetic manipulations easier. We propose the use of a series of new broad-host-range mini-Tn5-vectors, termed pBAMDs, for the delivery of gene(s) into the chromosome of Gram-negative bacteria and for generating saturated mutagenesis libraries in gene function studies. These delivery vectors endow the user with the possibility of easy cloning and subsequent insertion of functional cargoes with three different antibiotic-resistance markers (kanamycin, streptomycin, and gentamicin). After validating the pBAMD vectors in the environmental bacterium Pseudomonas putida KT2440, their use was also illustrated by inserting the entire poly(3-hydroxybutyrate) (PHB) synthesis pathway from Cupriavidus necator in the chromosome of a phosphotransacetylase mutant of Escherichia coli. PHB is a completely biodegradable polyester with a number of industrial applications that make it attractive as a potential replacement of oil-based plastics. The non-selective nature of chromosomal insertions of the biosynthetic genes was evidenced by a large landscape of PHB synthesis levels in independent clones. One clone was selected and further characterized as a microbial cell factory for PHB accumulation, and it achieved polymer accumulation levels comparable to those of a plasmid-bearing recombinant. Taken together, our results demonstrate that the new mini-Tn5-vectors can be used to confer interesting phenotypes in Gram-negative bacteria that would be very difficult to engineer through direct manipulation of the structural genes.

  5. New Transposon Tools Tailored for Metabolic Engineering of Gram-Negative Microbial Cell Factories

    Martínez-García, Esteban; Aparicio, Tomás; Lorenzo, Víctor de; Nikel, Pablo I., E-mail: pablo.nikel@cnb.csic.es [Systems and Synthetic Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Madrid (Spain)

    2014-10-28

    Re-programming microorganisms to modify their existing functions and/or to bestow bacteria with entirely new-to-Nature tasks have largely relied so far on specialized molecular biology tools. Such endeavors are not only relevant in the burgeoning metabolic engineering arena but also instrumental to explore the functioning of complex regulatory networks from a fundamental point of view. À la carte modification of bacterial genomes thus calls for novel tools to make genetic manipulations easier. We propose the use of a series of new broad-host-range mini-Tn5-vectors, termed pBAMDs, for the delivery of gene(s) into the chromosome of Gram-negative bacteria and for generating saturated mutagenesis libraries in gene function studies. These delivery vectors endow the user with the possibility of easy cloning and subsequent insertion of functional cargoes with three different antibiotic-resistance markers (kanamycin, streptomycin, and gentamicin). After validating the pBAMD vectors in the environmental bacterium Pseudomonas putida KT2440, their use was also illustrated by inserting the entire poly(3-hydroxybutyrate) (PHB) synthesis pathway from Cupriavidus necator in the chromosome of a phosphotransacetylase mutant of Escherichia coli. PHB is a completely biodegradable polyester with a number of industrial applications that make it attractive as a potential replacement of oil-based plastics. The non-selective nature of chromosomal insertions of the biosynthetic genes was evidenced by a large landscape of PHB synthesis levels in independent clones. One clone was selected and further characterized as a microbial cell factory for PHB accumulation, and it achieved polymer accumulation levels comparable to those of a plasmid-bearing recombinant. Taken together, our results demonstrate that the new mini-Tn5-vectors can be used to confer interesting phenotypes in Gram-negative bacteria that would be very difficult to engineer through direct manipulation of the structural genes.

  6. Metabolic heterogeneity in clonal microbial populations.

    Takhaveev, Vakil; Heinemann, Matthias

    2018-02-21

    In the past decades, numerous instances of phenotypic diversity were observed in clonal microbial populations, particularly, on the gene expression level. Much less is, however, known about phenotypic differences that occur on the level of metabolism. This is likely explained by the fact that experimental tools probing metabolism of single cells are still at an early stage of development. Here, we review recent exciting discoveries that point out different causes for metabolic heterogeneity within clonal microbial populations. These causes range from ecological factors and cell-inherent dynamics in constant environments to molecular noise in gene expression that propagates into metabolism. Furthermore, we provide an overview of current methods to quantify the levels of metabolites and biomass components in single cells. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. A review of metabolic and enzymatic engineering strategies for designing and optimizing performance of microbial cell factories

    Amanda K. Fisher

    2014-08-01

    Full Text Available Microbial cell factories (MCFs are of considerable interest to convert low value renewable substrates to biofuels and high value chemicals. This review highlights the progress of computational models for the rational design of an MCF to produce a target bio-commodity. In particular, the rational design of an MCF involves: (i product selection, (ii de novo biosynthetic pathway identification (i.e., rational, heterologous, or artificial, (iii MCF chassis selection, (iv enzyme engineering of promiscuity to enable the formation of new products, and (v metabolic engineering to ensure optimal use of the pathway by the MCF host. Computational tools such as (i de novo biosynthetic pathway builders, (ii docking, (iii molecular dynamics (MD and steered MD (SMD, and (iv genome-scale metabolic flux modeling all play critical roles in the rational design of an MCF. Genome-scale metabolic flux models are of considerable use to the design process since they can reveal metabolic capabilities of MCF hosts. These can be used for host selection as well as optimizing precursors and cofactors of artificial de novo biosynthetic pathways. In addition, recent advances in genome-scale modeling have enabled the derivation of metabolic engineering strategies, which can be implemented using the genomic tools reviewed here as well.

  8. Host genes related to paneth cells and xenobiotic metabolism are associated with shifts in human ileum-associated microbial composition.

    Tianyi Zhang

    Full Text Available The aim of this study was to integrate human clinical, genotype, mRNA microarray and 16 S rRNA sequence data collected on 84 subjects with ileal Crohn's disease, ulcerative colitis or control patients without inflammatory bowel diseases in order to interrogate how host-microbial interactions are perturbed in inflammatory bowel diseases (IBD. Ex-vivo ileal mucosal biopsies were collected from the disease unaffected proximal margin of the ileum resected from patients who were undergoing initial intestinal surgery. Both RNA and DNA were extracted from the mucosal biopsy samples. Patients were genotyped for the three major NOD2 variants (Leufs1007, R702W, and G908R and the ATG16L1T300A variant. Whole human genome mRNA expression profiles were generated using Agilent microarrays. Microbial composition profiles were determined by 454 pyrosequencing of the V3-V5 hypervariable region of the bacterial 16 S rRNA gene. The results of permutation based multivariate analysis of variance and covariance (MANCOVA support the hypothesis that host mucosal Paneth cell and xenobiotic metabolism genes play an important role in host microbial interactions.

  9. Single-cell genomics reveal metabolic strategies for microbial growth and survival in an oligotrophic aquifer

    Wilkins, Michael J.; Kennedy, David W.; Castelle, Cindy; Field, Erin; Stepanauskas, Ramunas; Fredrickson, Jim K.; Konopka, Allan

    2014-02-09

    Bacteria from the genus Pedobacter are a major component of microbial assemblages at Hanford Site and have been shown to significantly change in abundance in response to the subsurface intrusion of Columbia River water. Here we employed single cell genomics techniques to shed light on the physiological niche of these microorganisms. Analysis of four Pedobacter single amplified genomes (SAGs) from Hanford Site sediments revealed a chemoheterotrophic lifestyle, with the potential to exist under both aerobic and microaerophilic conditions via expression of both aa3­-type and cbb3-type cytochrome c oxidases. These SAGs encoded a wide-range of both intra-and extra­-cellular carbohydrate-active enzymes, potentially enabling the degradation of recalcitrant substrates such as xylan and chitin, and the utilization of more labile sugars such as mannose and fucose. Coupled to these enzymes, a diversity of transporters and sugar-binding molecules were involved in the uptake of carbon from the extracellular local environment. The SAGs were enriched in TonB-dependent receptors (TBDRs), which play a key role in uptake of substrates resulting from degradation of recalcitrant carbon. CRISPR-Cas mechanisms for resisting viral infections were identified in all SAGs. These data demonstrate the potential mechanisms utilized for persistence by heterotrophic microorganisms in a carbon-limited aquifer, and hint at potential linkages between observed Pedobacter abundance shifts within the 300 Area subsurface and biogeochemical shifts associated with Columbia River water intrusion.

  10. Arabinoxylo-Oligosaccharides and Inulin Impact Inter-Individual Variation on Microbial Metabolism and Composition, Which Immunomodulates Human Cells.

    Van den Abbeele, Pieter; Taminiau, Bernard; Pinheiro, Iris; Duysburgh, Cindy; Jacobs, Heidi; Pijls, Loek; Marzorati, Massimo

    2018-02-07

    Fecal batch fermentations coupled to cocultures of epithelial cells and macrophages were used to compare how arabinoxylo-oligosaccharides (AXOS) and inulin modulate gut microbial activity and composition of three different human donors and subsequently the epithelial permeability and immune response. Both inulin and AXOS decreased the pH during incubation (-1.5 pH units), leading to increased productions of acetate, propionate, and butyrate. Differences in terms of metabolites production could be linked to specific microbial alterations at genus level upon inulin/AXOS supplementation (i.e., Bifidobacterium, Bacteroides, Prevotella and unclassified Erysipelotrichaceae), as shown by 16S-targeted Illumina sequencing. Both products stimulated gut barrier and immune function with increases in TEER, NF-KB, IL-10, and IL-6. Ingredients with different structures selectively modulate the microbiota of a specific donor leading to differential changes at metabolic level. The extent of this effect is donor specific and is linked to a final specific modulation of the host's immune system.

  11. Enhancing microbial production of biofuels by expanding microbial metabolic pathways.

    Yu, Ping; Chen, Xingge; Li, Peng

    2017-09-01

    Fatty acid, isoprenoid, and alcohol pathways have been successfully engineered to produce biofuels. By introducing three genes, atfA, adhE, and pdc, into Escherichia coli to expand fatty acid pathway, up to 1.28 g/L of fatty acid ethyl esters can be achieved. The isoprenoid pathway can be expanded to produce bisabolene with a high titer of 900 mg/L in Saccharomyces cerevisiae. Short- and long-chain alcohols can also be effectively biosynthesized by extending the carbon chain of ketoacids with an engineered "+1" alcohol pathway. Thus, it can be concluded that expanding microbial metabolic pathways has enormous potential for enhancing microbial production of biofuels for future industrial applications. However, some major challenges for microbial production of biofuels should be overcome to compete with traditional fossil fuels: lowering production costs, reducing the time required to construct genetic elements and to increase their predictability and reliability, and creating reusable parts with useful and predictable behavior. To address these challenges, several aspects should be further considered in future: mining and transformation of genetic elements related to metabolic pathways, assembling biofuel elements and coordinating their functions, enhancing the tolerance of host cells to biofuels, and creating modular subpathways that can be easily interconnected. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  12. MICROBIAL FUEL CELL

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  13. [Improving industrial microbial stress resistance by metabolic engineering: a review].

    Fu, Ruiyan; Li, Yin

    2010-09-01

    Metabolic engineering is a technologic platform for industrial strain improvement and aims not only at modifying microbial metabolic fluxes, but also improving the physiological performance of industrial microbes. Microbes will meet multiple stresses in industrial processes. Consequently, elicited gene responses might result in a decrease in overall cell fitness and the efficiency of biotransformation. Thus, it is crucial to develop robust and productive microbial strains that can be integrated into industrial-scale bioprocesses. In this review, we focus on the progress of these novel methods and strategies for engineering stress-tolerance phenotypes referring to rational metabolic engineering and inverse metabolic engineering in recent years. In addition, we also address problems existing in this area and future research needs of microbial physiological functionality engineering.

  14. Microbial Metabolism and Inhibition Studies of Phenobarbital

    Erah

    techniques, high performance liquid chromatography (HPLC), mass spectrometry (MS) ... Keywords: Microbial metabolism, Phenobarbital, Inhibition studies, Rhizopus stolonifer, CYP 2C9, .... 24 h of incubation 0.5 ml of drug solution was ... mode, positive: spray voltage, 3.5 KV: ... Rhizopus stolonifer showed an extra peak at.

  15. Microbial Cell Dynamics Lab (MCDL)

    Federal Laboratory Consortium — The Microbial Cell Dynamics Laboratory at PNNL enables scientists to study the molecular details of microbes under relevant environmental conditions. The MCDL seeks...

  16. Microbial Cell Imaging

    Doktycz, Mitchel John [ORNL; Sullivan, Claretta [Eastern Virginia Medical School; Mortensen, Ninell P [ORNL; Allison, David P [ORNL

    2011-01-01

    limitation on the maximum scan size (roughly 100 x 100 {mu}m) and the restricted movement of the cantilever in the Z (or height) direction. In most commercial AFMs, the Z range is restricted to roughly 10 {mu}m such that the height of cells to be imaged must be seriously considered. Nevertheless, AFM can provide structural-functional information at nanometer resolution and do so in physiologically relevant environments. Further, instrumentation for scanning probe microscopy continues to advance. Systems for high-speed imaging are becoming available, and techniques for looking inside the cells are being demonstrated. The ability to combine AFM with other imaging modalities is likely to have an even greater impact on microbiological studies. AFM studies of intact microbial cells started to appear in the literature in the 1990s. For example, AFM studies of Saccharomyces cerevisiae examined buddings cars after cell division and detailed changes related to cell growth processes. Also, the first AFM studies of bacterial biofilms appeared. In the late 1990s, AFM studies of intact fungal spores described clear changes in spore surfaces upon germination, and studies of individual bacterial cells were also described. These early bacterial imaging studies examined changes in bacterial morphology due to antimicrobial peptides exposure and bacterial adhesion properties. The majority of these early studies were carried out on dried samples and took advantage of the resolving power of AFM. The lack of cell mounting procedures presented an impediment for cell imaging studies. Subsequently, several approaches to mounting microbial cells have been developed, and these techniques are described later. Also highlighted are general considerations for microbial imaging and a description of some of the various applications of AFM to microbiology.

  17. Engineering microbial fatty acid metabolism for biofuels and biochemicals

    Marella, Eko Roy; Holkenbrink, Carina; Siewers, Verena

    2017-01-01

    microbial catalysis. This review summarizes the recent advances in the engineering of microbial metabolism for production of fatty acid-derived products. We highlight the efforts in engineering the central carbon metabolism, redox metabolism, controlling the chain length of the products, and obtaining...

  18. Microbial electrosynthetic cells

    May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

    2018-01-30

    Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

  19. Microbial population heterogeneity versus bioreactor heterogeneity: evaluation of Redox Sensor Green as an exogenous metabolic biosensor

    Baert, Jonathan; Delepierre, Anissa; Telek, Samuel

    2016-01-01

    Microbial heterogeneity in metabolic performances has attracted a lot of attention, considering its potential impact on industrial bioprocesses. However, little is known about the impact of extracellular perturbations (i.e. bioreactor heterogeneity) on cell-to-cell variability in metabolic...

  20. Mechanistic links between gut microbial community dynamics, microbial functions and metabolic health

    Ha, Connie WY; Lam, Yan Y; Holmes, Andrew J

    2014-01-01

    Gut microbes comprise a high density, biologically active community that lies at the interface of an animal with its nutritional environment. Consequently their activity profoundly influences many aspects of the physiology and metabolism of the host animal. A range of microbial structural components and metabolites directly interact with host intestinal cells and tissues to influence nutrient uptake and epithelial health. Endocrine, neuronal and lymphoid cells in the gut also integrate signals from these microbial factors to influence systemic responses. Dysregulation of these host-microbe interactions is now recognised as a major risk factor in the development of metabolic dysfunction. This is a two-way process and understanding the factors that tip host-microbiome homeostasis over to dysbiosis requires greater appreciation of the host feedbacks that contribute to regulation of microbial community composition. To date, numerous studies have employed taxonomic profiling approaches to explore the links between microbial composition and host outcomes (especially obesity and its comorbidities), but inconsistent host-microbe associations have been reported. Available data indicates multiple factors have contributed to discrepancies between studies. These include the high level of functional redundancy in host-microbiome interactions combined with individual variation in microbiome composition; differences in study design, diet composition and host system between studies; and inherent limitations to the resolution of rRNA-based community profiling. Accounting for these factors allows for recognition of the common microbial and host factors driving community composition and development of dysbiosis on high fat diets. New therapeutic intervention options are now emerging. PMID:25469018

  1. Advanced Microscopy of Microbial Cells

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    Growing awareness of heterogeneity in cells of microbial populations has emphasized the importance of advanced microscopy for visualization and understanding of the molecular mechanisms underlying cell-to-cell variation. In this review, we highlight some of the recent advances in confocal...... microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  2. Metabolic modelling of polyhydroxyalkanoate copolymers production by mixed microbial cultures

    Reis Maria AM

    2008-07-01

    Full Text Available Abstract Background This paper presents a metabolic model describing the production of polyhydroxyalkanoate (PHA copolymers in mixed microbial cultures, using mixtures of acetic and propionic acid as carbon source material. Material and energetic balances were established on the basis of previously elucidated metabolic pathways. Equations were derived for the theoretical yields for cell growth and PHA production on mixtures of acetic and propionic acid as functions of the oxidative phosphorylation efficiency, P/O ratio. The oxidative phosphorylation efficiency was estimated from rate measurements, which in turn allowed the estimation of the theoretical yield coefficients. Results The model was validated with experimental data collected in a sequencing batch reactor (SBR operated under varying feeding conditions: feeding of acetic and propionic acid separately (control experiments, and the feeding of acetic and propionic acid simultaneously. Two different feast and famine culture enrichment strategies were studied: (i either with acetate or (ii with propionate as carbon source material. Metabolic flux analysis (MFA was performed for the different feeding conditions and culture enrichment strategies. Flux balance analysis (FBA was used to calculate optimal feeding scenarios for high quality PHA polymers production, where it was found that a suitable polymer would be obtained when acetate is fed in excess and the feeding rate of propionate is limited to ~0.17 C-mol/(C-mol.h. The results were compared with published pure culture metabolic studies. Conclusion Acetate was more conducive toward the enrichment of a microbial culture with higher PHA storage fluxes and yields as compared to propionate. The P/O ratio was not only influenced by the selected microbial culture, but also by the carbon substrate fed to each culture, where higher P/O ratio values were consistently observed for acetate than propionate. MFA studies suggest that when mixtures of

  3. Colorful Microbial Cell Factories

    Petersen, Pia Damm

    Yeast cell factories are powerful tools used for the production of high-value natural compounds otherwise not easily available. Many bioactive and industrially important plant secondary metabolites can be produced in yeast by engineering their biosynthetic pathways into yeast cells, as these both...... anthocyanins. Yeast cell factories present a platform to circumvent the problem of low yields of interesting molecular structures in plant tissues, as hand-picking of desired enzyme activities allows for specific biosynthesis of the precise pigment of interest, as well as choosing more stable structures...... for heterologous biosynthesis is possible. In cell factories, great improvements in yields can be achieved through molecular engineering of flux from endogenous yeast precursors, e.g. by elimination of by-product formation, and by genetic optimization of pathway components, such as fine-tuning of expression levels...

  4. Engineering Robustness of Microbial Cell Factories.

    Gong, Zhiwei; Nielsen, Jens; Zhou, Yongjin J

    2017-10-01

    Metabolic engineering and synthetic biology offer great prospects in developing microbial cell factories capable of converting renewable feedstocks into fuels, chemicals, food ingredients, and pharmaceuticals. However, prohibitively low production rate and mass concentration remain the major hurdles in industrial processes even though the biosynthetic pathways are comprehensively optimized. These limitations are caused by a variety of factors unamenable for host cell survival, such as harsh industrial conditions, fermentation inhibitors from biomass hydrolysates, and toxic compounds including metabolic intermediates and valuable target products. Therefore, engineered microbes with robust phenotypes is essential for achieving higher yield and productivity. In this review, the recent advances in engineering robustness and tolerance of cell factories is described to cope with these issues and briefly introduce novel strategies with great potential to enhance the robustness of cell factories, including metabolic pathway balancing, transporter engineering, and adaptive laboratory evolution. This review also highlights the integration of advanced systems and synthetic biology principles toward engineering the harmony of overall cell function, more than the specific pathways or enzymes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Microbial Heat Recovery Cell (MHRC) System Concept

    None

    2017-09-01

    This factsheet describes a project that aimed to develop a microbial heat recovery cell (MHRC) system that combines a microbial reverse electrodialysis technology with waste heat recovery to convert industrial effluents into electricity and hydrogen.

  6. Microbial food web components, bulk metabolism, and single-cell physiology of piconeuston in surface microlayers of high-altitude lakes

    Hugo eSarmento

    2015-05-01

    Full Text Available Sharp boundaries in the physical environment are usually associated with abrupt shifts in organism’s abundance, activity and diversity. Aquatic surface microlayers (SML form a steep gradient between two contrasted environments, the atmosphere and surface waters, where they regulate the gas exchange between both environments. They usually harbor an abundant and active microbial life: the neuston. Few ecosystems are subjected to such a high UVR regime as high altitude lakes during summer. Here, we measured bulk estimates of heterotrophic activity, community structure and single-cell physiological properties by flow cytometry in 19 high-altitude remote Pyrenean lakes and compared the biological processes in the SML with those in the underlying surface waters. Phototrophic picoplankton (PPP populations, were generally present in high abundances and in those lakes containing PPP populations with phycoerythrin (PE, total PPP abundance was higher at the SML. Heterotrophic nanoflagellates (HNF were also more abundant in the SML. Bacteria in the SµL had lower leucine incorporation rates, lower percentages of live cells, and higher numbers of highly-respiring cells, likely resulting in a lower growth efficiency. No simple and direct linear relationships could be found between microbial abundances or activities and environmental variables, but factor analysis revealed that, despite their physical proximity, microbial life in SML and underlying waters was governed by different and independent processes. Overall, we demonstrate that piconeuston in high altitude lakes has specific features different from those of the picoplankton, and that they are highly affected by potential stressful environmental factors, such as high UVR radiation.

  7. Microbial heterotrophic metabolic rates constrain the microbial carbon pump

    Robinson, C.; Ramaiah, N.

    (2008). 10. P.A. del Giorgio, J. J. Cole, in MicrobialEcologyoftheOceans D. L. Kirchman Ed. (JohnWiley & Sons, Inc. NewYork ed. 1. 2000),pp. 289–325. 11. A. B. Burd etal., DeepSeaRes.II 57, 1557 (2010). 12. S. Martinez-García, E. Fernández, M.... R.A. Straza, D. L. Kirchman, Aquat.Microb.Ecol. 62, 267(2011). 16. O. Hoegh-Guldberg, J. F. Bruno, Science 328,1523 (2010). 17. J. Piontek, M. Lunau, N. Handel, C. Borchard, M.Wurst,A. Engel, Biogeosciences 7, 1615 (2010). 18. J. K.Apple, P.A. del...

  8. Gut Microbial Glycerol Metabolism as an Endogenous Acrolein Source

    Zhang, Jianbo; Sturla, Shana; Lacroix, Christophe; Schwab, Clarissa

    2018-01-01

    ABSTRACT Acrolein is a highly reactive electrophile causing toxic effects, such as DNA and protein adduction, oxidative stress, endoplasmic reticulum stress, immune dysfunction, and membrane damage. This Opinion/Hypothesis provides an overview of endogenous and exogenous acrolein sources, acrolein’s mode of action, and its metabolic fate. Recent reports underpin the finding that gut microbial glycerol metabolism leading to the formation of reuterin is an additional source of endogenous acrole...

  9. Microbial Development and Metabolic Engineering | Bioenergy | NREL

    Diversity Our genetically engineered microbes utilize a variety of feedstock including cellulose, xylan , syngas, simple sugars, organic acids, and carbon dioxide (CO2). We have modified the metabolic pathways

  10. Deep-Sea Hydrothermal Vent Viruses Compensate for Microbial Metabolism in Virus-Host Interactions.

    He, Tianliang; Li, Hongyun; Zhang, Xiaobo

    2017-07-11

    Viruses are believed to be responsible for the mortality of host organisms. However, some recent investigations reveal that viruses may be essential for host survival. To date, it remains unclear whether viruses are beneficial or harmful to their hosts. To reveal the roles of viruses in the virus-host interactions, viromes and microbiomes of sediment samples from three deep-sea hydrothermal vents were explored in this study. To exclude the influence of exogenous DNAs on viromes, the virus particles were purified with nuclease (DNase I and RNase A) treatments and cesium chloride density gradient centrifugation. The metagenomic analysis of viromes without exogenous DNA contamination and microbiomes of vent samples indicated that viruses had compensation effects on the metabolisms of their host microorganisms. Viral genes not only participated in most of the microbial metabolic pathways but also formed branched pathways in microbial metabolisms, including pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; nitrogen metabolism and assimilation pathways of the two-component system; selenocompound metabolism; aminoacyl-tRNA biosynthesis; and amino sugar and nucleotide sugar metabolism. As is well known, deep-sea hydrothermal vent ecosystems exist in relatively isolated environments which are barely influenced by other ecosystems. The metabolic compensation of hosts mediated by viruses might represent a very important aspect of virus-host interactions. IMPORTANCE Viruses are the most abundant biological entities in the oceans and have very important roles in regulating microbial community structure and biogeochemical cycles. The relationship between virus and host microbes is broadly thought to be that of predator and prey. Viruses can lyse host cells to control microbial population sizes and affect community structures of hosts by killing specific microbes. However, viruses also influence their hosts through manipulation of bacterial metabolism. We found

  11. Microbial diversity and metabolic networks in acid mine drainage habitats

    Celia eMendez-Garcia

    2015-05-01

    Full Text Available Acid mine drainage (AMD emplacements are low-complexity natural systems. Low-pH conditions appear to be the main factor underlying the limited diversity of the microbial populations thriving in these environments, although temperature, ionic composition, total organic carbon and dissolved oxygen are also considered to significantly influence their microbial life. This natural reduction in diversity driven by extreme conditions was reflected in several studies on the microbial populations inhabiting the various micro-environments present in such ecosystems. Early studies based on the physiology of the autochthonous microbiota and the growing success of omics technologies have enabled a better understanding of microbial ecology and function in low-pH mine outflows; however, complementary omics-derived data should be included to completely describe their microbial ecology. Furthermore, recent updates on the distribution of eukaryotes and ultra-micro-archaea demand their inclusion in the microbial characterisation of AMD systems. In this review, we present a complete overview of the bacterial, archaeal (including ultra-micro-archaeal and eukaryotic diversity in these ecosystems and include a thorough depiction of the metabolism and element cycling in AMD habitats. We also review different metabolic network structures at the organismal level, which is necessary to disentangle the role of each member of the AMD communities described thus far.

  12. Towards the understanding of microbial metabolism in relation to microbial enhanced oil recovery

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Nielsen, Kristian Fog

    2017-01-01

    In this study, Bacillus licheniformis 421 was used as a model organism to understand the effects of microbial cell growth and metabolite production under anaerobic conditions in relation to microbial enhanced oil recovery. The bacterium was able to grow anaerobically on different carbon compounds...

  13. Microbial Regulation of Glucose Metabolism and Insulin Resistance

    Silke Crommen

    2017-12-01

    Full Text Available Type 2 diabetes is a combined disease, resulting from a hyperglycemia and peripheral and hepatic insulin resistance. Recent data suggest that the gut microbiota is involved in diabetes development, altering metabolic processes including glucose and fatty acid metabolism. Thus, type 2 diabetes patients show a microbial dysbiosis, with reduced butyrate-producing bacteria and elevated potential pathogens compared to metabolically healthy individuals. Furthermore, probiotics are a known tool to modulate the microbiota, having a therapeutic potential. Current literature will be discussed to elucidate the complex interaction of gut microbiota, intestinal permeability and inflammation leading to peripheral and hepatic insulin resistance. Therefore, this review aims to generate a deeper understanding of the underlying mechanism of potential microbial strains, which can be used as probiotics.

  14. Microbial Metabolism and Inhibition Studies of Phenobarbital ...

    Purpose: Screening scale studies were performed with eight cultures for their ability to metabolize phenobarbital, an antiepileptic, sedative, hypnotic and substrate for CYP 2C9 and 2C19. Methods: The transformation of phenobarbital was confirmed and characterized by fermentation techniques, high performance liquid ...

  15. Nitrate metabolism in the gromiid microbial universe

    Høgslund, Signe; Risgaard-Petersen, Nils; Cedhagen, Tomas

    enclose and regulate a small biogeochemical universe within their cell. Their transparent proteinaceous cell wall surrounds a complex matrix consisting of sediment, bacteria and nitrate which is concentrated to hundreds of mM in the gromiid cell. The nitrate is respired to dinitrogen, but in contrast...

  16. Arsenic and selenium in microbial metabolism

    Stolz, John F.; Basu, Partha; Santini, Joanne M.; Oremland, Ronald S.

    2006-01-01

    Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environments. Respiratory arsenate reductases, arsenic methyltransferases, and new components in arsenic resistance have been recently described. The requirement for selenium stems primarily from its incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can serve as an electron acceptor in anaerobic respiration, forming distinct nanoparticles of elemental selenium that may be enriched in (76)Se. The biogenesis of selenoproteins has been elucidated, and selenium methyltransferases and a respiratory selenate reductase have also been described. This review highlights recent advances in ecology, biochemistry, and molecular biology and provides a prelude to the impact of genomics studies.

  17. Microbial community assembly and metabolic function during mammalian corpse decomposition

    Metcalf, J. L.; Xu, Z. Z.; Weiss, S.; Lax, S.; Van Treuren, W.; Hyde, E. R.; Song, S. J.; Amir, A.; Larsen, P.; Sangwan, N.; Haarmann, D.; Humphrey, G. C.; Ackermann, G.; Thompson, L. R.; Lauber, C.; Bibat, A.; Nicholas, C.; Gebert, M. J.; Petrosino, J. F.; Reed, S. C.; Gilbert, J. A.; Lynne, A. M.; Bucheli, S. R.; Carter, D. O.; Knight, R.

    2015-12-10

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.

  18. Microbial community assembly and metabolic function during mammalian corpse decomposition

    Metcalf, Jessica L; Xu, Zhenjiang Zech; Weiss, Sophie; Lax, Simon; Van Treuren, Will; Hyde, Embriette R.; Song, Se Jin; Amir, Amnon; Larsen, Peter; Sangwan, Naseer; Haarmann, Daniel; Humphrey, Greg C; Ackermann, Gail; Thompson, Luke R; Lauber, Christian; Bibat, Alexander; Nicholas, Catherine; Gebert, Matthew J; Petrosino, Joseph F; Reed, Sasha C.; Gilbert, Jack A; Lynne, Aaron M; Bucheli, Sibyl R; Carter, David O; Knight, Rob

    2016-01-01

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.

  19. The Role of Microbial Amino Acid Metabolism in Host Metabolism

    Evelien P. J. G. Neis

    2015-04-01

    Full Text Available Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous proteins. In turn, gut bacteria also provide amino acids to the host. This could have significant implications in the context of insulin resistance and type 2 diabetes mellitus, conditions associated with elevated systemic concentrations of certain amino acids, in particular the aromatic and branched-chain amino acids. Moreover, several amino acids released by gut bacteria can serve as precursors for the synthesis of short-chain fatty acids, which also play a role in the development of obesity. In this review, we aim to compile the available evidence on the contribution of microbial amino acids to host amino acid homeostasis, and to assess the role of the gut microbiota as a determinant of amino acid and short-chain fatty acid perturbations in human obesity and type 2 diabetes mellitus.

  20. Effects of introducing heterologous pathways on microbial metabolism with respect to metabolic optimality

    Kim, Hyun Uk; Kim, Byoungjin; Seung, Do Young

    2014-01-01

    reactions are more frequently introduced into various microbial hosts. The genome-scale metabolic simulations of Escherichia coli strains engineered to produce 1,4-butanediol, 1,3-propanediol, and amorphadiene suggest that microbial metabolism shows much different responses to the introduced heterologous...... reactions in a strain-specific manner than typical gene knockouts in terms of the energetic status (e.g., ATP and biomass generation) and chemical production capacity. The 1,4-butanediol and 1,3-propanediol producers showed greater metabolic optimality than the wild-type strains and gene knockout mutants...... for the energetic status, while the amorphadiene producer was metabolically less optimal. For the optimal chemical production capacity, additional gene knockouts were most effective for the strain producing 1,3-propanediol, but not for the one producing 1,4-butanediol. These observations suggest that strains having...

  1. Changes in Microbial Energy Metabolism Measured by Nanocalorimetry during Growth Phase Transitions

    Robador, Alberto; LaRowe, Douglas E.; Finkel, Steven E.; Amend, Jan P.; Nealson, Kenneth H.

    2018-01-01

    Calorimetric measurements of the change in heat due to microbial metabolic activity convey information about the kinetics, as well as the thermodynamics, of all chemical reactions taking place in a cell. Calorimetric measurements of heat production made on bacterial cultures have recorded the energy yields of all co-occurring microbial metabolic reactions, but this is a complex, composite signal that is difficult to interpret. Here we show that nanocalorimetry can be used in combination with enumeration of viable cell counts, oxygen consumption rates, cellular protein content, and thermodynamic calculations to assess catabolic rates of an isolate of Shewanella oneidensis MR-1 and infer what fraction of the chemical energy is assimilated by the culture into biomass and what fraction is dissipated in the form of heat under different limiting conditions. In particular, our results demonstrate that catabolic rates are not necessarily coupled to rates of cell division, but rather, to physiological rearrangements of S. oneidensis MR-1 upon growth phase transitions. In addition, we conclude that the heat released by growing microorganisms can be measured in order to understand the physiochemical nature of the energy transformation and dissipation associated with microbial metabolic activity in conditions approaching those found in natural systems. PMID:29449836

  2. Metabolic-flux dependent regulation of microbial physiology.

    Litsios, Athanasios; Ortega, Álvaro D; Wit, Ernst C; Heinemann, Matthias

    2018-04-01

    According to the most prevalent notion, changes in cellular physiology primarily occur in response to altered environmental conditions. Yet, recent studies have shown that changes in metabolic fluxes can also trigger phenotypic changes even when environmental conditions are unchanged. This suggests that cells have mechanisms in place to assess the magnitude of metabolic fluxes, that is, the rate of metabolic reactions, and use this information to regulate their physiology. In this review, we describe recent evidence for metabolic flux-sensing and flux-dependent regulation. Furthermore, we discuss how such sensing and regulation can be mechanistically achieved and present a set of new candidates for flux-signaling metabolites. Similar to metabolic-flux sensing, we argue that cells can also sense protein translation flux. Finally, we elaborate on the advantages that flux-based regulation can confer to cells. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Gut Microbial Glycerol Metabolism as an Endogenous Acrolein Source

    Jianbo Zhang

    2018-01-01

    Full Text Available Acrolein is a highly reactive electrophile causing toxic effects, such as DNA and protein adduction, oxidative stress, endoplasmic reticulum stress, immune dysfunction, and membrane damage. This Opinion/Hypothesis provides an overview of endogenous and exogenous acrolein sources, acrolein’s mode of action, and its metabolic fate. Recent reports underpin the finding that gut microbial glycerol metabolism leading to the formation of reuterin is an additional source of endogenous acrolein. Reuterin is an antimicrobial multicomponent system consisting of 3-hydroxypropionaldehyde, its dimer and hydrate, and also acrolein. The major conclusion is that gut microbes can metabolize glycerol to reuterin and that this transformation occurs in vivo. Given the known toxicity of acrolein, the observation that acrolein is formed in the gut necessitates further investigations on functional relevance for gut microbiota and the host.

  4. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

  5. Metabolic and demographic feedbacks shape the emergent spatial structure and function of microbial communities.

    Sylvie Estrela

    Full Text Available Microbes are predominantly found in surface-attached and spatially structured polymicrobial communities. Within these communities, microbial cells excrete a wide range of metabolites, setting the stage for interspecific metabolic interactions. The links, however, between metabolic and ecological interactions (functional relationships, and species spatial organization (structural relationships are still poorly understood. Here, we use an individual-based modelling framework to simulate the growth of a two-species surface-attached community where food (resource is traded for detoxification (service and investigate how metabolic constraints of individual species shape the emergent structural and functional relationships of the community. We show that strong metabolic interdependence drives the emergence of mutualism, robust interspecific mixing, and increased community productivity. Specifically, we observed a striking and highly stable emergent lineage branching pattern, generating a persistent lineage mixing that was absent when the metabolic exchange was removed. These emergent community properties are driven by demographic feedbacks, such that aid from neighbouring cells directly enhances focal cell growth, which in turn feeds back to neighbour fecundity. In contrast, weak metabolic interdependence drives conflict (exploitation or competition, and in turn greater interspecific segregation. Together, these results support the idea that species structural and functional relationships represent the net balance of metabolic interdependencies.

  6. Coupling Spatiotemporal Community Assembly Processes to Changes in Microbial Metabolism

    Graham, Emily B.; Crump, Alex R.; Resch, Charles T.; Fansler, Sarah; Arntzen, Evan; Kennedy, David W.; Fredrickson, Jim K.; Stegen, James C.

    2016-12-16

    Community assembly processes govern shifts in species abundances in response to environmental change, yet our understanding of assembly remains largely decoupled from ecosystem function. Here, we test hypotheses regarding assembly and function across space and time using hyporheic microbial communities as a model system. We pair sampling of two habitat types through hydrologic fluctuation with null modeling and multivariate statistics. We demonstrate that dual selective pressures assimilate to generate compositional changes at distinct timescales among habitat types, resulting in contrasting associations of Betaproteobacteria and Thaumarchaeota with selection and with seasonal changes in aerobic metabolism. Our results culminate in a conceptual model in which selection from contrasting environments regulates taxon abundance and ecosystem function through time, with increases in function when oscillating selection opposes stable selective pressures. Our model is applicable within both macrobial and microbial ecology and presents an avenue for assimilating community assembly processes into predictions of ecosystem function.

  7. Soil Microbial Community Contribution to Small Headwater Stream Metabolism.

    Clapcott, J. E.; Gooderham, J. P.; Barmuta, L. A.; Davies, P. E.

    2005-05-01

    The temporal dynamics of sediment respiration were examined in seven small headwater streams in forested catchments in 2004. A strong seasonal response was observed with higher respiration rates in depositional zones than in gravel runs. The data were also examined in the context of proportional habitat distributions that highlighted the importance of high flow events in shaping whole stream metabolic budgets. This study specifically examines the question of terrestrial soil respiration contribution to whole stream metabolism by the controlled inundation of terrestrial soils. The experiment included six experimentally inundated terrestrial zones, six terrestrial controls, and six in-stream depositional zones. Sediment bacterial respiration was measured using 14C leucine incorporation and cotton strip bioassays were also employed to provide an indicative measure of sediment microbial activity. Despite high variability and exhibiting significantly lower bacterial activity than in-stream sediments, modelling using flow data and habitat mapping illustrated the important contribution of terrestrial soil respiration to the whole stream metabolic budgets of small headwater streams. In addition, microbial community composition examined using phospholipid fatty acid analysis clearly differentiated between terrestrial and aquatic communities. Freshly inundated terrestrial communities remained similar to un-inundated controls after 28 days.

  8. Advanced Microscopy of Microbial Cells

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  9. Microbial production of antioxidant food ingredients via metabolic engineering.

    Lin, Yuheng; Jain, Rachit; Yan, Yajun

    2014-04-01

    Antioxidants are biological molecules with the ability to protect vital metabolites from harmful oxidation. Due to this fascinating role, their beneficial effects on human health are of paramount importance. Traditional approaches using solvent-based extraction from food/non-food sources and chemical synthesis are often expensive, exhaustive, and detrimental to the environment. With the advent of metabolic engineering tools, the successful reconstitution of heterologous pathways in Escherichia coli and other microorganisms provides a more exciting and amenable alternative to meet the increasing demand of natural antioxidants. In this review, we elucidate the recent progress in metabolic engineering efforts for the microbial production of antioxidant food ingredients - polyphenols, carotenoids, and antioxidant vitamins. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Pseudomonas putida as a microbial cell factory

    Wigneswaran, Vinoth

    for sustainable production of chemicals, which can be achieved by microbial cell factories. The work presented in this PhD thesis elucidates the application of Pseudomonas putida as a microbial cell factory for production of the biosurfactant rhamnolipid. The rhamnolipid production was achieved by heterologous...... phase. The genomic alterations were identified by genome sequencing and revealed parallel evolution. Glycerol was also shown to be able to support biofilm growth and as a result of this it can be used as an alternative substrate for producing biochemicals in conventional and biofilm reactors. The use...... of biofilm as a production platform and the usage of glycerol as a feedstock show the potential of using microbial cell factories in the transition toward sustainable production of chemicals. Particularly, the applicability of biofilm as a production platform can emerge as a promising alternative...

  11. Recent Advances in Microbial Single Cell Genomics Technology and Applications

    Stepanauskas, R.

    2016-02-01

    Single cell genomics is increasingly utilized as a powerful tool to decipher the metabolic potential, evolutionary histories and in situ interactions of environmental microorganisms. This transformative technology recovers extensive information from cultivation-unbiased samples of individual, unicellular organisms. Thus, it does not require data binning into arbitrary phylogenetic or functional groups and therefore is highly compatible with agent-based modeling approaches. I will present several technological advances in this field, which significantly improve genomic data recovery from individual cells and provide direct linkages between cell's genomic and phenotypic properties. I will also demonstrate how these new technical capabilities help understanding the metabolic potential and viral infections of the "microbial dark matter" inhabiting aquatic and subsurface environments.

  12. Balancing cellular redox metabolism in microbial electrosynthesis and electro fermentation - A chance for metabolic engineering.

    Kracke, Frauke; Lai, Bin; Yu, Shiqin; Krömer, Jens O

    2018-01-01

    More and more microbes are discovered that are capable of extracellular electron transfer, a process in which they use external electrodes as electron donors or acceptors for metabolic reactions. This feature can be used to overcome cellular redox limitations and thus optimizing microbial production. The technologies, termed microbial electrosynthesis and electro-fermentation, have the potential to open novel bio-electro production platforms from sustainable energy and carbon sources. However, the performance of reported systems is currently limited by low electron transport rates between microbes and electrodes and our limited ability for targeted engineering of these systems due to remaining knowledge gaps about the underlying fundamental processes. Metabolic engineering offers many opportunities to optimize these processes, for instance by genetic engineering of pathways for electron transfer on the one hand and target product synthesis on the other hand. With this review, we summarize the status quo of knowledge and engineering attempts around chemical production in bio-electrochemical systems from a microbe perspective. Challenges associated with the introduction or enhancement of extracellular electron transfer capabilities into production hosts versus the engineering of target compound synthesis pathways in natural exoelectrogens are discussed. Recent advances of the research community in both directions are examined critically. Further, systems biology approaches, for instance using metabolic modelling, are examined for their potential to provide insight into fundamental processes and to identify targets for metabolic engineering. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  13. Graphene-Based Flexible Micrometer-Sized Microbial Fuel Cell

    Mink, Justine E.; Qaisi, Ramy M.; Hussain, Muhammad Mustafa

    2013-01-01

    Microbial fuel cells harvest electrical energy produced by bacteria during the natural decomposition of organic matter. We report a micrometer-sized microbial fuel cell that is able to generate nanowatt-scale power from microliters of liquids

  14. Interval scanning photomicrography of microbial cell populations.

    Casida, L. E., Jr.

    1972-01-01

    A single reproducible area of the preparation in a fixed focal plane is photographically scanned at intervals during incubation. The procedure can be used for evaluating the aerobic or anaerobic growth of many microbial cells simultaneously within a population. In addition, the microscope is not restricted to the viewing of any one microculture preparation, since the slide cultures are incubated separately from the microscope.

  15. Ecophysiology of microorganisms in microbial elctrolysis cells

    Croese, E.

    2012-01-01

    One of the main challenges for improvement of the microbial electrolysis cell (MEC) has been the reduction of the cost of the cathode catalyst. As catalyst at the cathode, microorganisms offer great possibilities. Previous research has shown the principle possibilities for the biocathode for H2

  16. Microbial fuel cell: A green technology

    Jong Bor Chyan; Liew Pauline Woan Ying; Muhamad Lebai Juri; Ahmad Zainuri Mohd Dzomir; Leo Kwee Wah; Mat Rasol Awang

    2010-01-01

    Microbial Fuel Cell (MFC) was developed which was able to generate bio energy continuously while consuming wastewater containing organic matters. Even though the bio energy generated is not as high as hydrogen fuel cell, the MFC demonstrated great potential in bio-treating wastewater while using it as fuel source. Thus far, the dual-ability of the MFC to generate bio energy and bio-treating organic wastewater has been examined successfully using synthetic acetate and POME wastewaters. (author)

  17. Electricity production and microbial characterization of thermophilic microbial fuel cells.

    Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

    2017-11-01

    Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Integrated hydrogen production process from cellulose by combining dark fermentation, microbial fuel cells, and a microbial electrolysis cell

    Wang, Aijie; Sun, Dan; Cao, Guangli; Wang, Haoyu; Ren, Nanqi; Wu, Wei-Min; Logan, Bruce E.

    2011-01-01

    Hydrogen gas production from cellulose was investigated using an integrated hydrogen production process consisting of a dark fermentation reactor and microbial fuel cells (MFCs) as power sources for a microbial electrolysis cell (MEC). Two MFCs

  19. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  20. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  1. Use of genome-scale microbial models for metabolic engineering

    Patil, Kiran Raosaheb; Åkesson, M.; Nielsen, Jens

    2004-01-01

    Metabolic engineering serves as an integrated approach to design new cell factories by providing rational design procedures and valuable mathematical and experimental tools. Mathematical models have an important role for phenotypic analysis, but can also be used for the design of optimal metaboli...... network structures. The major challenge for metabolic engineering in the post-genomic era is to broaden its design methodologies to incorporate genome-scale biological data. Genome-scale stoichiometric models of microorganisms represent a first step in this direction....

  2. Microbial regulation of GLP-1 and L-cell biology

    Greiner, Thomas U; Bäckhed, Gert Fredrik

    2016-01-01

    BACKGROUND: The gut microbiota is associated with several of metabolic diseases, including obesity and type 2 diabetes and affects host physiology through distinct mechanisms. The microbiota produces a vast array of metabolites that signal to host cells in the intestine as well as in more distal...... organs. SCOPE OF REVIEW: Enteroendocrine cells acts as 'chemo sensors' of the intestinal milieu by expressing a large number of receptors, which respond to different metabolites and nutrients, and signal to host by a wide variety of hormones. However, enteroendocrine cells differ along the length...... of the gut in terms of hormones expressed and receptor repertoire. Also, the microbial ecology and dietary substrates differ along the length of the gut, providing further evidence for unique functions of specific subpopulations among enteroendocrine cells. Here we will review how the gut microbiota...

  3. Hydrodynamic chronoamperometry for probing kinetics of anaerobic microbial metabolism--case study of Faecalibacterium prausnitzii.

    Prévoteau, Antonin; Geirnaert, Annelies; Arends, Jan B A; Lannebère, Sylvain; Van de Wiele, Tom; Rabaey, Korneel

    2015-07-01

    Monitoring in vitro the metabolic activity of microorganisms aids bioprocesses and enables better understanding of microbial metabolism. Redox mediators can be used for this purpose via different electrochemical techniques that are either complex or only provide non-continuous data. Hydrodynamic chronoamperometry using a rotating disc electrode (RDE) can alleviate these issues but was seldom used and is poorly characterized. The kinetics of Faecalibacterium prausnitzii A2-165, a beneficial gut microbe, were determined using a RDE with riboflavin as redox probe. This butyrate producer anaerobically ferments glucose and reduces riboflavin whose continuous monitoring on a RDE provided highly accurate kinetic measurements of its metabolism, even at low cell densities. The metabolic reaction rate increased linearly over a broad range of cell concentrations (9 × 10(4) to 5 × 10(7) cells.mL(-1)). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM = 6 μM; kcat = 5.3 × 10(5) s(-1), at 37 °C) and glucose (KM = 6 μM; kcat = 2.4 × 10(5) s(-1)). The short temporal resolution allows continuous monitoring of fast cellular events such as kinetics inhibition with butyrate. Furthermore, we detected for the first time riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum. The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution.

  4. Exoelectrogenic bacteria that power microbial fuel cells

    Logan, Bruce E.

    2009-01-01

    There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

  5. Exoelectrogenic bacteria that power microbial fuel cells

    Logan, Bruce E.

    2009-03-30

    There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

  6. Solar energy powered microbial fuel cell with a reversible bioelectrode

    Strik, D.P.B.T.B.; Hamelers, H.V.M.; Buisman, C.J.N.

    2010-01-01

    The solar energy powered microbial fuel cell is an emerging technology for electricity generation via electrochemically active microorganisms fueled by solar energy via in situ photosynthesized metabolites from algae, cyanobacteria, or living higher plants. A general problem with microbial fuel

  7. Microbial pathways in colonic sulfur metabolism and links with health and disease

    Franck eCarbonero

    2012-11-01

    Full Text Available Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites or organic (e.g., dietary amino acids and host mucins origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria, which are common colonic inhabitants. Many other microbial pathways are likely to shape colonic sulfur metabolism as well as the composition and availability of sulfated compounds, and these interactions need to be examined in more detail. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in the context of colonic health, and the extent to which it is detrimental or beneficial remains in debate. Several lines of evidence point to sulfate-reducing bacteria or exogenous hydrogen sulfide as potential players in the etiology of intestinal disorders, inflammatory bowel diseases and colorectal cancer in particular. Generation of hydrogen sulfide via pathways other than dissimilatory sulfate reduction may be as, or more, important than those involving the sulfate-reducing bacteria. We suggest here that a novel axis of research is to assess the effects of hydrogen sulfide in shaping colonic microbiome structure. Clearly, in-depth characterization of the microbial pathways involved in colonic sulfur metabolism is necessary for a better understanding of its contribution to colonic disorders and development of therapeutic strategies.

  8. Application of biocathode in microbial fuel cells: cell performance and microbial community

    Guo-Wei, Chen [Pusan National Univ. (Korea). Dept. of Environmental Engineering; Hefei Univ. of Technology (China). School of Civil Engineering; Choi, Soo-Jung; Lee, Tae-Ho; Lee, Gil-Young; Cha, Jae-Hwan; Kim, Chang-Won [Pusan National Univ. (Korea). Dept. of Environmental Engineering

    2008-06-15

    Instead of the utilization of artificial redox mediators or other catalysts, a biocathode has been applied in a two-chamber microbial fuel cell in this study, and the cell performance and microbial community were analyzed. After a 2-month startup, the microorganisms of each compartment in microbial fuel cell were well developed, and the output of microbial fuel cell increased and became stable gradually, in terms of electricity generation. At 20 ml/min flow rate of the cathodic influent, the maximum power density reached 19.53 W/m{sup 3}, while the corresponding current and cell voltage were 15.36 mA and 223 mV at an external resistor of 14.9 {omega}, respectively. With the development of microorganisms in both compartments, the internal resistance decreased from initial 40.2 to 14.0 {omega}, too. Microbial community analysis demonstrated that five major groups of the clones were categorized among those 26 clone types derived from the cathode microorganisms. Betaproteobacteria was the most abundant division with 50.0% (37 of 74) of the sequenced clones in the cathode compartment, followed by 21.6% (16 of 74) Bacteroidetes, 9.5% (7 of 74) Alphaproteobacteria, 8.1% (6 of 74) Chlorobi, 4.1% (3 of 74) Deltaproteobacteria, 4.1% (3 of 74) Actinobacteria, and 2.6% (2 of 74) Gammaproteobacteria. (orig.)

  9. Microbial mutagenesis and cell division

    Adler, H.I.; Carrasco, A.; Nagel, R.; Gill, J.S.; Crow, W.D.

    1982-01-01

    Our group has been pursuing three related objectives. The first of these is a study of a mechanism by which the bacterium Escherichia coli repairs radiation-induced damage. In particular, we have observed that cells of certain strains of this bacterium, mutant at the lon locus, can be restored to viability after exposure to ionizing radiation if they are incubated in a nutrient medium to which a preparation of partially purified bacterial membranes has been added. These preparations stimulate division by producing chemical alterations in the nutrient medium and simultaneously creating a highly anaerobic environment. A second objective of the group was to make use of lon mutants for a rapid, sensitive, and inexpensive assay for chemical mutagens. Cells of lon mutants form long multinucleate filaments if exposed to a variety of agents that react with DNA. These filaments can readily be observed microscopically 2 to 3 h after exposure to the suspect agent. A third objective of our group has been to make use of the oxygen reducing properties of bacterial membrane preparations to stimulate the growth of anaerobic bacteria. Our general goal is to develop basic microbiological techniques that will facilitate the application of genetic manipulation methods to important anaerobic species. To this end, we have developed a method, based on the use of membranes, that allows us to grow liquid cultures of Clostridium acetobutylicum from very small inocula to high titers without elaborate chemical or physical methods for excluding oxygen. We have also developed efficient methods for plating this bacterium that do not require the use of anaerobic incubators

  10. Rumen microbial communities influence metabolic phenotypes in lambs

    Diego P. Morgavi

    2015-10-01

    Full Text Available The rumen microbiota is an essential part of ruminants forging their nutrition and health. Despite its importance, it is not fully understood how various groups of rumen microbes affect host-microbe relationships and functions. The aim of the study was to simultaneously explore the rumen microbiota and the metabolic phenotype of lambs for identifying host-microbe associations and potential biomarkers of digestive functions. Twin lambs, separated in two groups after birth were exposed to practices (isolation and gavage with rumen fluid with protozoa or protozoa-depleted that differentially restricted the acquisition of microbes. Rumen microbiota, fermentation parameters, digestibility and growth were monitored for up to 31 weeks of age. Microbiota assembled in isolation from other ruminants lacked protozoa and had low bacterial and archaeal diversity whereas digestibility was not affected. Exposure to adult sheep microbiota increased bacterial and archaeal diversity independently of protozoa presence. For archaea, Methanomassiliicoccales displaced Methanosphaera. Notwithstanding, protozoa induced differences in functional traits such as digestibility and significantly shaped bacterial community structure, notably Ruminococcaceae and Lachnospiraceae lower up to 6 folds, Prevotellaceae lower by ~40%, and Clostridiaceae and Veillonellaceae higher up to 10 folds compared to microbiota without protozoa. An orthogonal partial least squares-discriminant analysis of urinary metabolome matched differences in microbiota structure. Discriminant metabolites were mainly involved in amino acids and protein metabolic pathways while a negative interaction was observed between methylotrophic methanogens Methanomassiliicoccales and trimethylamine N-oxide. These results stress the influence of gut microbes on animal phenotype and show the potential of metabolomics for monitoring rumen microbial functions.

  11. Evolving Microbial Communities in Cellulose-Fed Microbial Fuel Cell

    Renata Toczyłowska-Mamińska

    2018-01-01

    Full Text Available The abundance of cellulosic wastes make them attractive source of energy for producing electricity in microbial fuel cells (MFCs. However, electricity production from cellulose requires obligate anaerobes that can degrade cellulose and transfer electrons to the electrode (exoelectrogens, and thus most previous MFC studies have been conducted using two-chamber systems to avoid oxygen contamination of the anode. Single-chamber, air-cathode MFCs typically produce higher power densities than aqueous catholyte MFCs and avoid energy input for the cathodic reaction. To better understand the bacterial communities that evolve in single-chamber air-cathode MFCs fed cellulose, we examined the changes in the bacterial consortium in an MFC fed cellulose over time. The most predominant bacteria shown to be capable electron generation was Firmicutes, with the fermenters decomposing cellulose Bacteroidetes. The main genera developed after extended operation of the cellulose-fed MFC were cellulolytic strains, fermenters and electrogens that included: Parabacteroides, Proteiniphilum, Catonella and Clostridium. These results demonstrate that different communities evolve in air-cathode MFCs fed cellulose than the previous two-chamber reactors.

  12. Compartmentalized metabolic network reconstruction of microbial communities to determine the effect of agricultural intervention on soils

    Álvarez-Yela, Astrid Catalina; Gómez-Cano, Fabio; Zambrano, María Mercedes; Husserl, Johana; Danies, Giovanna; Restrepo, Silvia; González-Barrios, Andrés Fernando

    2017-01-01

    Soil microbial communities are responsible for a wide range of ecological processes and have an important economic impact in agriculture. Determining the metabolic processes performed by microbial communities is crucial for understanding and managing ecosystem properties. Metagenomic approaches allow the elucidation of the main metabolic processes that determine the performance of microbial communities under different environmental conditions and perturbations. Here we present the first compartmentalized metabolic reconstruction at a metagenomics scale of a microbial ecosystem. This systematic approach conceives a meta-organism without boundaries between individual organisms and allows the in silico evaluation of the effect of agricultural intervention on soils at a metagenomics level. To characterize the microbial ecosystems, topological properties, taxonomic and metabolic profiles, as well as a Flux Balance Analysis (FBA) were considered. Furthermore, topological and optimization algorithms were implemented to carry out the curation of the models, to ensure the continuity of the fluxes between the metabolic pathways, and to confirm the metabolite exchange between subcellular compartments. The proposed models provide specific information about ecosystems that are generally overlooked in non-compartmentalized or non-curated networks, like the influence of transport reactions in the metabolic processes, especially the important effect on mitochondrial processes, as well as provide more accurate results of the fluxes used to optimize the metabolic processes within the microbial community. PMID:28767679

  13. Compartmentalized metabolic network reconstruction of microbial communities to determine the effect of agricultural intervention on soils.

    María Camila Alvarez-Silva

    Full Text Available Soil microbial communities are responsible for a wide range of ecological processes and have an important economic impact in agriculture. Determining the metabolic processes performed by microbial communities is crucial for understanding and managing ecosystem properties. Metagenomic approaches allow the elucidation of the main metabolic processes that determine the performance of microbial communities under different environmental conditions and perturbations. Here we present the first compartmentalized metabolic reconstruction at a metagenomics scale of a microbial ecosystem. This systematic approach conceives a meta-organism without boundaries between individual organisms and allows the in silico evaluation of the effect of agricultural intervention on soils at a metagenomics level. To characterize the microbial ecosystems, topological properties, taxonomic and metabolic profiles, as well as a Flux Balance Analysis (FBA were considered. Furthermore, topological and optimization algorithms were implemented to carry out the curation of the models, to ensure the continuity of the fluxes between the metabolic pathways, and to confirm the metabolite exchange between subcellular compartments. The proposed models provide specific information about ecosystems that are generally overlooked in non-compartmentalized or non-curated networks, like the influence of transport reactions in the metabolic processes, especially the important effect on mitochondrial processes, as well as provide more accurate results of the fluxes used to optimize the metabolic processes within the microbial community.

  14. Unravelling core microbial metabolisms in the hypersaline microbial mats of Shark Bay using high-throughput metagenomics

    Ruvindy, Rendy; White III, Richard Allen; Neilan, Brett Anthony; Burns, Brendan Paul

    2015-05-29

    Modern microbial mats are potential analogues of some of Earth’s earliest ecosystems. Excellent examples can be found in Shark Bay, Australia, with mats of various morphologies. To further our understanding of the functional genetic potential of these complex microbial ecosystems, we conducted for the first time shotgun metagenomic analyses. We assembled metagenomic nextgeneration sequencing data to classify the taxonomic and metabolic potential across diverse morphologies of marine mats in Shark Bay. The microbial community across taxonomic classifications using protein-coding and small subunit rRNA genes directly extracted from the metagenomes suggests that three phyla Proteobacteria, Cyanobacteria and Bacteriodetes dominate all marine mats. However, the microbial community structure between Shark Bay and Highbourne Cay (Bahamas) marine systems appears to be distinct from each other. The metabolic potential (based on SEED subsystem classifications) of the Shark Bay and Highbourne Cay microbial communities were also distinct. Shark Bay metagenomes have a metabolic pathway profile consisting of both heterotrophic and photosynthetic pathways, whereas Highbourne Cay appears to be dominated almost exclusively by photosynthetic pathways. Alternative non-rubisco-based carbon metabolism including reductive TCA cycle and 3-hydroxypropionate/4-hydroxybutyrate pathways is highly represented in Shark Bay metagenomes while not represented in Highbourne Cay microbial mats or any other mat forming ecosystems investigated to date. Potentially novel aspects of nitrogen cycling were also observed, as well as putative heavy metal cycling (arsenic, mercury, copper and cadmium). Finally, archaea are highly represented in Shark Bay and may have critical roles in overall ecosystem function in these modern microbial mats.

  15. Anode microbial communities produced by changing from microbial fuel cell to microbial electrolysis cell operation using two different wastewaters

    Kiely, Patrick D.; Cusick, Roland; Call, Douglas F.; Selembo, Priscilla A.; Regan, John M.; Logan, Bruce E.

    2011-01-01

    Conditions in microbial fuel cells (MFCs) differ from those in microbial electrolysis cells (MECs) due to the intrusion of oxygen through the cathode and the release of H2 gas into solution. Based on 16S rRNA gene clone libraries, anode communities in reactors fed acetic acid decreased in species richness and diversity, and increased in numbers of Geobacter sulfurreducens, when reactors were shifted from MFCs to MECs. With a complex source of organic matter (potato wastewater), the proportion of Geobacteraceae remained constant when MFCs were converted into MECs, but the percentage of clones belonging to G. sulfurreducens decreased and the percentage of G. metallireducens clones increased. A dairy manure wastewater-fed MFC produced little power, and had more diverse microbial communities, but did not generate current in an MEC. These results show changes in Geobacter species in response to the MEC environment and that higher species diversity is not correlated with current. © 2010 Elsevier Ltd.

  16. Metaproteomics: extracting and mining proteome information to characterize metabolic activities in microbial communities.

    Abraham, Paul E; Giannone, Richard J; Xiong, Weili; Hettich, Robert L

    2014-06-17

    Contemporary microbial ecology studies usually employ one or more "omics" approaches to investigate the structure and function of microbial communities. Among these, metaproteomics aims to characterize the metabolic activities of the microbial membership, providing a direct link between the genetic potential and functional metabolism. The successful deployment of metaproteomics research depends on the integration of high-quality experimental and bioinformatic techniques for uncovering the metabolic activities of a microbial community in a way that is complementary to other "meta-omic" approaches. The essential, quality-defining informatics steps in metaproteomics investigations are: (1) construction of the metagenome, (2) functional annotation of predicted protein-coding genes, (3) protein database searching, (4) protein inference, and (5) extraction of metabolic information. In this article, we provide an overview of current bioinformatic approaches and software implementations in metaproteome studies in order to highlight the key considerations needed for successful implementation of this powerful community-biology tool. Copyright © 2014 John Wiley & Sons, Inc.

  17. Does canine inflammatory bowel disease influence gut microbial profile and host metabolism?

    Xu, Jia; Verbrugghe, Adronie; Louren?o, Marta; Janssens, Geert P. J.; Liu, Daisy J. X.; Van de Wiele, Tom; Eeckhaut, Venessa; Van Immerseel, Filip; Van de Maele, Isabel; Niu, Yufeng; Bosch, Guido; Junius, Greet; Wuyts, Brigitte; Hesta, Myriam

    2016-01-01

    Background Inflammatory bowel disease (IBD) refers to a diverse group of chronic gastrointestinal diseases, and gut microbial dysbiosis has been proposed as a modulating factor in its pathogenesis. Several studies have investigated the gut microbial ecology of dogs with IBD but it is yet unclear if this microbial profile can alter the nutrient metabolism of the host. The aim of the present study was to characterize the faecal bacterial profile and functionality as well as to determine host me...

  18. MICROBIAL CELL-SURFACE HYDROPHOBICITY - THE INVOLVEMENT OF ELECTROSTATIC INTERACTIONS IN MICROBIAL ADHESION TO HYDROCARBONS (MATH)

    GEERTSEMADOORNBUSCH, GI; VANDERMEI, HC; BUSSCHER, HJ

    Microbial adhesion to hydrocarbons (MATH) is the most commonly used method to determine microbial cell surface hydrophobicity. Since, however, the assay is based on adhesion, it is questionable whether the results reflect only the cell surface hydrophobicity or an interplay of hydrophobicity and

  19. Snail modulates cell metabolism in MDCK cells

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  20. Variation in antibiotic-induced microbial recolonization impacts on the host metabolic phenotypes of rats.

    Swann, Jonathan R; Tuohy, Kieran M; Lindfors, Peter; Brown, Duncan T; Gibson, Glenn R; Wilson, Ian D; Sidaway, James; Nicholson, Jeremy K; Holmes, Elaine

    2011-08-05

    The interaction between the gut microbiota and their mammalian host is known to have far-reaching consequences with respect to metabolism and health. We investigated the effects of eight days of oral antibiotic exposure (penicillin and streptomycin sulfate) on gut microbial composition and host metabolic phenotype in male Han-Wistar rats (n = 6) compared to matched controls. Early recolonization was assessed in a third group exposed to antibiotics for four days followed by four days recovery (n = 6). Fluorescence in situ hybridization analysis of the intestinal contents collected at eight days showed a significant reduction in all bacterial groups measured (control, 10(10.7) cells/g feces; antibiotic-treated, 10(8.4)). Bacterial suppression reduced the excretion of mammalian-microbial urinary cometabolites including hippurate, phenylpropionic acid, phenylacetylglycine and indoxyl-sulfate whereas taurine, glycine, citrate, 2-oxoglutarate, and fumarate excretion was elevated. While total bacterial counts remained notably lower in the recolonized animals (10(9.1) cells/g faeces) compared to the controls, two cage-dependent subgroups emerged with Lactobacillus/Enterococcus probe counts dominant in one subgroup. This dichotomous profile manifested in the metabolic phenotypes with subgroup differences in tricarboxylic acid cycle metabolites and indoxyl-sulfate excretion. Fecal short chain fatty acids were diminished in all treated animals. Antibiotic treatment induced a profound effect on the microbiome structure, which was reflected in the metabotype. Moreover, the recolonization process was sensitive to the microenvironment, which may impact on understanding downstream consequences of antibiotic consumption in human populations.

  1. Cancer Cell Metabolism: One Hallmark, Many Faces

    Cantor, Jason R.; Sabatini, David M.

    2012-01-01

    Cancer cells must rewire cellular metabolism to satisfy the demands of growth and proliferation. Although many of the metabolic alterations are largely similar to those in normal proliferating cells, they are aberrantly driven in cancer by a combination of genetic lesions and nongenetic factors such as the tumor microenvironment. However, a single model of altered tumor metabolism does not describe the sum of metabolic changes that can support cell growth. Instead, the diversity of such chang...

  2. Microbial electrolysis cells as innovative technology for hydrogen production

    Chorbadzhiyska, Elitsa; Hristov, Georgi; Mitov, Mario; Hubenova, Yolina

    2011-01-01

    Hydrogen production is becoming increasingly important in view of using hydrogen in fuel cells. However, most of the production of hydrogen so far comes from the combustion of fossil fuels and water electrolysis. Microbial Electrolysis Cell (MEC), also known as Bioelectrochemically Assisted Microbial Reactor, is an ecologically clean, renewable and innovative technology for hydrogen production. Microbial electrolysis cells produce hydrogen mainly from waste biomass assisted by various bacteria strains. The principle of MECs and their constructional elements are reviewed and discussed. Keywords: microbial Electrolysis Cells, hydrogen production, waste biomass purification

  3. Melphalan metabolism in cultured cells

    Seagrave, J.C.; Valdez, J.G.; Tobey, R.A.; Gurley, L.R.

    1985-06-01

    Procedures are presented for the adaptation of reversed-phase-HPLC methods to accomplish separation and isolation of the cancer therapeutic drug melphalan (L-phenylalanine mustard) and its metabolic products from whole cells. Five major degradation products of melphalan were observed following its hydrolysis in phosphate buffer in vitro. The two most polar of these products (or modifications of them) were also found in the cytosol of Chinese hamster CHO cells. The amounts of these two polar products (shown not to be mono- or dihydroxymelphalan) were significantly changed by the pretreatment of cells with ZnC1 2 , one being increased in amount while the other was reduced to an insignificant level. In ZnC1 2 -treated cells, there was also an increased binding of melphalan (or its derivatives) to one protein fraction resolved by gel filtration-HPLC. These observations suggest that changes in polar melphalan products, and perhaps their interaction with a protein, may by involved in the reduction of melphalan cytotoxicity observed in ZnC1 2 -treated cells. While ZnC1 2 is also known to increase the level of glutathione in cells, no significant amounts of glutathione-melphalan derivatives of the type formed non-enzymatically in vitro could be detected in ZnC1 2 -treated or untreated cells. Formation of derivatives of melphalan with glutathione catabolic products in ZnC1 2 -treated cells has not yet been eliminated, however. 17 refs., 5 figs., 1 tab

  4. Shape recognition of microbial cells by colloidal cell imprints

    Borovicka, J.; Stoyanov, S.D.; Paunov, V.N.

    2013-01-01

    We have engineered a class of colloids which can recognize the shape and size of targeted microbial cells and selectively bind to their surfaces. These imprinted colloid particles, which we called "colloid antibodies", were fabricated by partial fragmentation of silica shells obtained by templating

  5. Energy Harvesting From River Sediment Using a Microbial Fuel Cell: Preliminary Results

    Philippe Namour

    2014-05-01

    Full Text Available We have built a sedimentary fuel cell or Sediment Microbial Fuel Cell (SMFC. The device works on the principle of microbial fuel cells by exploiting directly the energy contained in sedimentary organic matter. It converts in electricity the sediment potential, thanks to microorganisms able to waste electrons from their metabolism directly to a solid anode instead of their natural electron acceptors, such as oxygen or nitrate. The sediment microbial fuel cell was made of a non-corrodible anode (graphite buried in anoxic sediments layer and connected via an electrical circuit to a cathode installed in surface water. We present the first results of laboratory sedimentary fuel cell and a prototype installed in the river.

  6. Alternative Cell Death Pathways and Cell Metabolism

    Simone Fulda

    2013-01-01

    Full Text Available While necroptosis has for long been viewed as an accidental mode of cell death triggered by physical or chemical damage, it has become clear over the last years that necroptosis can also represent a programmed form of cell death in mammalian cells. Key discoveries in the field of cell death research, including the identification of critical components of the necroptotic machinery, led to a revised concept of cell death signaling programs. Several regulatory check and balances are in place in order to ensure that necroptosis is tightly controlled according to environmental cues and cellular needs. This network of regulatory mechanisms includes metabolic pathways, especially those linked to mitochondrial signaling events. A better understanding of these signal transduction mechanisms will likely contribute to open new avenues to exploit our knowledge on the regulation of necroptosis signaling for therapeutic application in the treatment of human diseases.

  7. A role for programmed cell death in the microbial loop.

    Mónica V Orellana

    Full Text Available The microbial loop is the conventional model by which nutrients and minerals are recycled in aquatic eco-systems. Biochemical pathways in different organisms become metabolically inter-connected such that nutrients are utilized, processed, released and re-utilized by others. The result is that unrelated individuals end up impacting each others' fitness directly through their metabolic activities. This study focused on the impact of programmed cell death (PCD on a population's growth as well as its role in the exchange of carbon between two naturally co-occurring halophilic organisms. Flow cytometric, biochemical, ¹⁴C radioisotope tracing assays, and global transcriptomic analyses show that organic algal photosynthate released by Dunalliela salina cells undergoing PCD complements the nutritional needs of other non-PCD D. salina cells. This occurs in vitro in a carbon limited environment and enhances the growth of the population. In addition, a co-occurring heterotroph Halobacterium salinarum re-mineralizes the carbon providing elemental nutrients for the mixoheterotrophic chlorophyte. The significance of this is uncertain and the archaeon can also subsist entirely on the lysate of apoptotic algae. PCD is now well established in unicellular organisms; however its ecological relevance has been difficult to decipher. In this study we found that PCD in D. salina causes the release of organic nutrients such as glycerol, which can be used by others in the population as well as a co-occurring halophilic archaeon. H. salinarum also re-mineralizes the dissolved material promoting algal growth. PCD in D. salina was the mechanism for the flow of dissolved photosynthate between unrelated organisms. Ironically, programmed death plays a central role in an organism's own population growth and in the exchange of nutrients in the microbial loop.

  8. Hydrodynamic chronoamperometry for probing kinetics of anaerobic microbial metabolism - case study of Faecalibacterium prausnitzii

    Prévoteau, Antonin; Geirnaert, Annelies; Arends, Jan B. A.; Lannebère, Sylvain; van de Wiele, Tom; Rabaey, Korneel

    2015-07-01

    Monitoring in vitro the metabolic activity of microorganisms aids bioprocesses and enables better understanding of microbial metabolism. Redox mediators can be used for this purpose via different electrochemical techniques that are either complex or only provide non-continuous data. Hydrodynamic chronoamperometry using a rotating disc electrode (RDE) can alleviate these issues but was seldom used and is poorly characterized. The kinetics of Faecalibacterium prausnitzii A2-165, a beneficial gut microbe, were determined using a RDE with riboflavin as redox probe. This butyrate producer anaerobically ferments glucose and reduces riboflavin whose continuous monitoring on a RDE provided highly accurate kinetic measurements of its metabolism, even at low cell densities. The metabolic reaction rate increased linearly over a broad range of cell concentrations (9 × 104 to 5 × 107 cells.mL-1). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM = 6 μM kcat = 5.3×105 s-1, at 37 °C) and glucose (KM = 6 μM kcat = 2.4 × 105 s-1). The short temporal resolution allows continuous monitoring of fast cellular events such as kinetics inhibition with butyrate. Furthermore, we detected for the first time riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum. The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution.

  9. Metabolic network modeling of microbial interactions in natural and engineered environmental systems

    Octavio ePerez-Garcia

    2016-05-01

    Full Text Available We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains. To date however, such models have been rarely applied to analyze and control the metabolism of more complex microbial communities. This is largely attributed to the diversity of microbial community functions, metabolisms and interactions. Here, we firstly review different types of microbial interaction and describe their relevance for natural and engineered environmental processes. Next, we provide a general description of the essential methods of the SMN modeling workflow including the steps of network reconstruction, simulation through Flux Balance Analysis (FBA, experimental data gathering, and model calibration. Then we broadly describe and compare four approaches to model microbial interactions using metabolic networks, i.e. i lumped networks, ii compartment per guild networks, iii bi-level optimization simulations and iv dynamic-SMN methods. These approaches can be used to integrate and analyze diverse microbial physiology, ecology and molecular community data. All of them (except the lumped approach are suitable for incorporating species abundance data but so far they have been used only to model simple communities of two to eight different species. Interactions based on substrate exchange and competition can be directly modeled using the above approaches. However, interactions based on metabolic feedbacks, such as product inhibition and synthropy require extensions to current models, incorporating gene regulation and compounding accumulation mechanisms. SMN models of microbial

  10. Penanganan limbah industri dengan cara immobilisasi microbial cell

    Prayitno Prayitno

    1997-12-01

    Full Text Available An immobilized microbial cell is a physical confinement or localization of intact cell to a certain defined region of space with the preservation of some desired catalytic activity. The immobilization cell process has been increasingly used, one of those is for waste water treatment industry. Microbial entrapping process one of the method for the microbial cell immobilization by using some carrier such as collagen, gelatin, alginate, carragena and cellulose tri acetat at the time being is commonly used. Immobilization cell is effective enough for waste water treatment containing toxic substance such as phenol and by using immobilization cell, secondary sedimentation tanks is no longer used.

  11. GENOME-BASED MODELING AND DESIGN OF METABOLIC INTERACTIONS IN MICROBIAL COMMUNITIES

    Radhakrishnan Mahadevan

    2012-10-01

    With the advent of genome sequencing, omics technologies, bioinformatics and genome-scale modeling, researchers now have unprecedented capabilities to analyze and engineer the metabolism of microbial communities. The goal of this review is to summarize recent applications of genome-scale metabolic modeling to microbial communities. A brief introduction to lumped community models is used to motivate the need for genome-level descriptions of individual species and their metabolic interactions. The review of genome-scale models begins with static modeling approaches, which are appropriate for communities where the extracellular environment can be assumed to be time invariant or slowly varying. Dynamic extensions of the static modeling approach are described, and then applications of genome-scale models for design of synthetic microbial communities are reviewed. The review concludes with a summary of metagenomic tools for analyzing community metabolism and an outlook for future research.

  12. Microbial Fuel Cells under Extreme Salinity

    Monzon del Olmo, Oihane

    I developed a Microbial Fuel Cell (MFC) that unprecedentedly works (i.e., produces electricity) under extreme salinity (≈ 100 g/L NaCl). Many industries, such as oil and gas extraction, generate hypersaline wastewaters with high organic strength, accounting for about 5% of worldwide generated effluents, which represent a major challenge for pollution control and resource recovery. This study assesses the potential for microbial fuel cells (MFCs) to treat such wastewaters and generate electricity under extreme saline conditions. Specifically, the focus is on the feasibility to treat hypersaline wastewater generated by the emerging unconventional oil and gas industry (hydraulic fracturing) and so, with mean salinity of 100 g/L NaCl (3-fold higher than sea water). The success of this novel technology strongly depends on finding a competent and resilient microbial community that can degrade the waste under extreme saline conditions and be able to use the anode as their terminal electron acceptor (exoelectrogenic capability). I demonstrated that MFCs can produce electricity at extremely high salinity (up to 250 g/l NaCl) with a power production of 71mW/m2. Pyrosequencing analysis of the anode population showed the predominance of Halanaerobium spp. (85%), which has been found in shale formations and oil reservoirs. Promoting Quorum sensing (QS, cell to cell communication between bacteria to control gene expression) was used as strategy to increase the attachment of bacteria to the anode and thus improve the MFC performance. Results show that the power output can be bolstered by adding 100nM of quinolone signal with an increase in power density of 30%, for the first time showing QS in Halanaerobium extremophiles. To make this technology closer to market applications, experiments with real wastewaters were also carried out. A sample of produced wastewater from Barnet Shale, Texas (86 g/L NaCl) produced electricity when fed in an MFC, leading to my discovery of another

  13. Cancer cell metabolism: one hallmark, many faces.

    Cantor, Jason R; Sabatini, David M

    2012-10-01

    Cancer cells must rewire cellular metabolism to satisfy the demands of growth and proliferation. Although many of the metabolic alterations are largely similar to those in normal proliferating cells, they are aberrantly driven in cancer by a combination of genetic lesions and nongenetic factors such as the tumor microenvironment. However, a single model of altered tumor metabolism does not describe the sum of metabolic changes that can support cell growth. Instead, the diversity of such changes within the metabolic program of a cancer cell can dictate by what means proliferative rewiring is driven, and can also impart heterogeneity in the metabolic dependencies of the cell. A better understanding of this heterogeneity may enable the development and optimization of therapeutic strategies that target tumor metabolism.

  14. ELECTRICITY GENERATION FROM SWINE WASTEWATER USING MICROBIAL FUEL CELL

    Chimezie Jason Ogugbue

    2015-11-01

    Full Text Available Electricity generation from swine wastewater using microbial fuel cell (MFC was investigated. Swine wastewater was collected into dual-chambered (aerobic and anaerobic fuel cell. The maximum power output using copper and carbon electrodes were 250.54 and 52.33 µW, while 10.0 and 5.0 cm salt bridge length between the cathode and anode were 279.50 and 355.26 µW, respectively. Potassium permanganate and ordinal water gave a maximum power output of 1287.8 and 13 9.18 µW. MFCs utilize microbial communities to degrade organic materials found within wastewater and converted stored chemical energy to electrical energy in a single step. The initial bacterial and fungal counts were 7.4×106 and 1.1×103 CFU ml-1. Bacterial counts steadily increased with time to 1.40×107 CFU ml-1 while fungal count declined to 4.4×106 CFU ml-1 after day 60. The declined in microbial counts may be attributed to the time necessary for acclimatization of microbes to the anode. The genera identified were Bacillus, Citrobacter, Pseudomonas, Lactobacillus, Escherichia coli, Aspergillus and Rhizopus. These microbes acted as primary and secondary utilizers, utilizing carbon and other organics of the wastewater. Chemical parameters indicated that the biochemical oxygen demand ranged from 91.4–23.2 mg/L, giving 75% while the chemical oxygen demand ranged from 243.1–235.2 mg/L, representing 3.3%. Although, the metabolic activities of microbes were responsible for the observed degradation, leading to electricity, the overall power output depended on the distance between the anode and cathode compartment, types of electrode materials and mediators and oxygen reaction at the cathode.

  15. Endotoxins, Glucans and Other Microbial Cell Wall Agents

    Basinas, Ioannis; Elholm, Grethe; Wouters, Inge M.

    2017-01-01

    During the last decades an increasing interest in microbial cell wall agents has been established, since exposure to these agents has been linked to a wide range of adverse and beneficial health effects. The term microbial cell wall agents refers to a group of molecules of different composition that

  16. Energy from algae using microbial fuel cells

    Velasquez-Orta, Sharon B.

    2009-08-15

    Bioelectricity production froma phytoplankton, Chlorella vulgaris, and a macrophyte, Ulva lactuca was examined in single chamber microbial fuel cells (MFCs). MFCs were fed with the two algae (as powders), obtaining differences in energy recovery, degradation efficiency, and power densities. C. vulgaris produced more energy generation per substrate mass (2.5 kWh/kg), but U. lactuca was degraded more completely over a batch cycle (73±1% COD). Maximum power densities obtained using either single cycle or multiple cycle methods were 0.98 W/m2 (277 W/m3) using C. vulgaris, and 0.76 W/m2 (215 W/m3) using U. lactuca. Polarization curves obtained using a common method of linear sweep voltammetry (LSV) overestimated maximum power densities at a scan rate of 1 mV/s. At 0.1 mV/s, however, the LSV polarization data was in better agreement with single- and multiple-cycle polarization curves. The fingerprints of microbial communities developed in reactors had only 11% similarity to inocula and clustered according to the type of bioprocess used. These results demonstrate that algae can in principle, be used as a renewable source of electricity production in MFCs. © 2009 Wiley Periodicals, Inc.

  17. Energy from algae using microbial fuel cells

    Velasquez-Orta, Sharon B.; Curtis, Tom P.; Logan, Bruce E.

    2009-01-01

    Bioelectricity production froma phytoplankton, Chlorella vulgaris, and a macrophyte, Ulva lactuca was examined in single chamber microbial fuel cells (MFCs). MFCs were fed with the two algae (as powders), obtaining differences in energy recovery, degradation efficiency, and power densities. C. vulgaris produced more energy generation per substrate mass (2.5 kWh/kg), but U. lactuca was degraded more completely over a batch cycle (73±1% COD). Maximum power densities obtained using either single cycle or multiple cycle methods were 0.98 W/m2 (277 W/m3) using C. vulgaris, and 0.76 W/m2 (215 W/m3) using U. lactuca. Polarization curves obtained using a common method of linear sweep voltammetry (LSV) overestimated maximum power densities at a scan rate of 1 mV/s. At 0.1 mV/s, however, the LSV polarization data was in better agreement with single- and multiple-cycle polarization curves. The fingerprints of microbial communities developed in reactors had only 11% similarity to inocula and clustered according to the type of bioprocess used. These results demonstrate that algae can in principle, be used as a renewable source of electricity production in MFCs. © 2009 Wiley Periodicals, Inc.

  18. Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

    Peng, Qiannan; Jiang, Shuaiming; Chen, Jieling; Ma, Chenchen; Huo, Dongxue; Shao, Yuyu; Zhang, Jiachao

    2018-01-01

    Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing tropical microbial

  19. Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

    Qiannan Peng

    2018-03-01

    Full Text Available Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing

  20. Engineering microbial cell factories for the production of plant natural products: from design principles to industrial-scale production.

    Liu, Xiaonan; Ding, Wentao; Jiang, Huifeng

    2017-07-19

    Plant natural products (PNPs) are widely used as pharmaceuticals, nutraceuticals, seasonings, pigments, etc., with a huge commercial value on the global market. However, most of these PNPs are still being extracted from plants. A resource-conserving and environment-friendly synthesis route for PNPs that utilizes microbial cell factories has attracted increasing attention since the 1940s. However, at the present only a handful of PNPs are being produced by microbial cell factories at an industrial scale, and there are still many challenges in their large-scale application. One of the challenges is that most biosynthetic pathways of PNPs are still unknown, which largely limits the number of candidate PNPs for heterologous microbial production. Another challenge is that the metabolic fluxes toward the target products in microbial hosts are often hindered by poor precursor supply, low catalytic activity of enzymes and obstructed product transport. Consequently, despite intensive studies on the metabolic engineering of microbial hosts, the fermentation costs of most heterologously produced PNPs are still too high for industrial-scale production. In this paper, we review several aspects of PNP production in microbial cell factories, including important design principles and recent progress in pathway mining and metabolic engineering. In addition, implemented cases of industrial-scale production of PNPs in microbial cell factories are also highlighted.

  1. Microbial fuel cell as new technol

    Mostafa Rahimnejad

    2015-09-01

    Full Text Available Recently, great attentions have been paid to microbial fuel cells (MFCs due to their mild operating conditions and using variety of biodegradable substrates as fuel. The traditional MFC consisted of anode and cathode compartments but there are single chamber MFCs. Microorganisms actively catabolize substrate, and bioelectricities are generated. MFCs could be utilized as power generator in small devices such as biosensor. Besides the advantages of this technology, it still faces practical barriers such as low power and current density. In the present article different parts of MFC such as anode, cathode and membrane have been reviewed and to overcome the practical challenges in this field some practical options have been suggested. Also, this research review demonstrates the improvement of MFCs with summarization of their advantageous and possible applications in future application. Also, Different key factors affecting bioelectricity generation on MFCs were investigated and these key parameters are fully discussed.

  2. Hydrocarbon fermentation: kinetics of microbial cell growth

    Goma, G [Institut National des Sciences Appliquees, Toulouse; Ribot, D

    1978-11-01

    Modeling of microbial growth using nonmiscible substrate is studied when kinetics of substrate dissolution is rate limiting. When the substrate concentration is low, the growth rate is described by an analytical relation that can be identified as a Contois relationship. If the substrate concentration is greater than a critical value S/sub crit/, the potentially useful hydrocarbon S* concentration is described by S* = S/sub crit//(1 + S/sub crit//S). A relationship was found between S/sub crit/ and the biomass concentration X. When X increased, S/sub crit/ decreased. The cell growth rate is related to a relation ..mu.. = ..mu../sub m/(A(X/S/sub crit/)(1 + S/sub crit//S) + 1)/sup -1/. This model describes the evolution of the growth rate when exponential or linear growth occurs, which is related to physico-chemical properties and hydrodynamic fermentation conditions. Experimental data to support the model are presented.

  3. Electrospinning of microbial polyester for cell culture

    Kwon, Oh Hyeong [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Lee, Ik Sang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Ko, Young-Gwang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Meng, Wan [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Jung, Kyung-Hye [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kang, Inn-Kyu [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Ito, Yoshihiro [Kanagawa Academy of Science and Technology, KSP East 309, Sakado 3-2-1, Takatsu-ku, Kawasaki 213-0012 (Japan)

    2007-03-01

    Biodegradable and biocompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a copolymer of microbial polyester, was fabricated as a nanofibrous mat by electrospinning. The specific surface area and the porosity of electrospun PHBV nanofibrous mat were determined. When the mechanical properties of flat film and electrospun PHBV nanofibrous mats were investigated, both the tensile modulus and strength of electrospun PHBV were less than those of cast PHBV film. However, the elongation ratio of nanofiber mat was higher than that of the cast film. The structure of electrospun nanofibers using PHBV-trifluoroethanol solutions depended on the solution concentrations. When x-ray diffraction patterns of bulk PHBV before and after electrospinning were compared, the crystallinity of PHBV was not significantly affected by the electrospinning process. Chondrocytes adhered and grew on the electrospun PHBV nanofibrous mat better than on the cast PHBV film. Therefore, the electrospun PHBV was considered to be suitable for cell culture.

  4. Microbial fuel cells and microbial electrolysis cells for the production of bioelectricity and biomaterials.

    Zhou, Minghua; Yang, Jie; Wang, Hongyu; Jin, Tao; Xu, Dake; Gu, Tingyue

    2013-01-01

    Today's global energy crisis requires a multifaceted solution. Bioenergy is an important part of the solution. The microbial fuel cell (MFC) technology stands out as an attractive potential technology in bioenergy. MFCs can convert energy stored in organic matter directly into bioelectricity. MFCs can also be operated in the electrolysis mode as microbial electrolysis cells to produce bioproducts such as hydrogen and ethanol. Various wastewaters containing low-grade organic carbons that are otherwise unutilized can be used as feed streams for MFCs. Despite major advances in the past decade, further improvements in MFC power output and cost reduction are needed for MFCs to be practical. This paper analysed MFC operating principles using bioenergetics and bioelectrochemistry. Several major issues were explored to improve the MFC performance. An emphasis was placed on the use of catalytic materials for MFC electrodes. Recent advances in the production of various biomaterials using MFCs were also investigated.

  5. Microbial electro-catalysis in fuel cell

    Dumas, Claire

    2007-01-01

    Microbial fuel cells (MFC) are devices that ensure the direct conversion of organic matter into electricity using bacterial bio-films as the catalysts of the electrochemical reactions. This study aims at improving the comprehension of the mechanisms involved in electron transfer pathways between the adhered bacteria and the electrodes. This optimization of the MFC power output could be done, for example, in exploring and characterizing various electrode materials. The electrolysis experiments carried out on Geobacter sulfurreducens deal with the microbial catalysis of the acetate oxidation, on the one hand, and the catalysis of the fumarate reduction on the other hand. On the anodic side, differences in current densities appeared on graphite, DSA R and stainless steel (8 A/m 2 , 5 A/m 2 and 0.7 A/m 2 respectively). These variations were explained more by materials roughness differences rather than their nature. Impedance spectroscopy study shows that the electro-active bio-film developed on stainless steel does not seem to modify the evolution of the stainless steel oxide layer, only the imposed potential remains determining. On the cathodic side, stainless steel sustained current densities more than twenty times higher than those obtained with graphite electrodes. The adhesion study of G. sulfurreducens on various materials in a flow cell, suggests that the bio-films resist to the hydrodynamic constraints and are not detached under a shear stress threshold value. The installation of two MFC prototypes, one in a sea station and the other directly in Genoa harbour (Italy) confirms some results obtained in laboratory and were promising for a MFC scale-up. (author) [fr

  6. Luminescence materials for pH and oxygen sensing in microbial cells - structures, optical properties, and biological applications.

    Zou, Xianshao; Pan, Tingting; Chen, Lei; Tian, Yanqing; Zhang, Weiwen

    2017-09-01

    Luminescence including fluorescence and phosphorescence sensors have been demonstrated to be important for studying cell metabolism, and diagnosing diseases and cancer. Various design principles have been employed for the development of sensors in different formats, such as organic molecules, polymers, polymeric hydrogels, and nanoparticles. The integration of the sensing with fluorescence imaging provides valuable tools for biomedical research and applications at not only bulk-cell level but also at single-cell level. In this article, we critically reviewed recent progresses on pH, oxygen, and dual pH and oxygen sensors specifically for their application in microbial cells. In addition, we focused not only on sensor materials with different chemical structures, but also on design and applications of sensors for better understanding cellular metabolism of microbial cells. Finally, we also provided an outlook for future materials design and key challenges in reaching broad applications in microbial cells.

  7. Microbial Metabolic Roles in Bedrock Degradation and the Genesis of Biomineral and Biopattern Biosignatures in Caves and Mines

    Boston, P. J.

    2016-12-01

    In subsurface environments like natural or anthropogenic caves (aka mines), microorganisms facilitate considerable bedrock degradation under a variety of circumstances. Mobilization of materials from these processes frequently produces distinctive biominerals, identifiable biotextures, and unique biopatterns. Microbial activities can even determine the form of speleothems (secondary mineral cave decorations), thus providing highly conspicuous macroscopic biosignatures. It is critical to understand microbial-mineral interactions, recognizing that while the lithology controls important aspects of the environment, in turn, the geochemistry is greatly affected by the biology. Microbial communities can contribute to the actual formation of cavities (speleogenesis), and subsequent enlargement of caves and vugs and the mineral deposits that enrich many subterranean spaces. A major challenge is to quantify such influences. Genetic analysis is revealing a vast but highly partitioned biodiversity in the overall rock fracture habitat of Earth's crust especially in caves and mines where the three phases of matter (solid rock, fluids, and gases) typically interact producing high niche richness. Lessons learned from the microbial/geochemical systems that we have studied include: 1) significant similarities in metabolic functions between different geochemical systems, 2) ubiquity of metal oxidation for energy, 3) ubiquity of biofilms, some highly mineralized, 4) highly interdependent, multi-species communities that can only transform materials in consortia, 5) complex ecological succession including characteristic pioneer species, 6) often very slow growth rates in culture, 7) prevalence of very small cell sizes, ( 100 - 500 nm diam.), 8) mineral reprecipitation of mobilized materials, often dependent on the presence of live microbial communities to produce initial amorphous compounds followed by gradual crystallization, and 9) resultant in situ self-fossilization. Microbial

  8. Metabolic engineering for the microbial production of isoprenoids: Carotenoids and isoprenoid-based biofuels

    Fu-Xing Niu

    2017-09-01

    Full Text Available Isoprenoids are the most abundant and highly diverse group of natural products. Many isoprenoids have been used for pharmaceuticals, nutraceuticals, flavors, cosmetics, food additives and biofuels. Carotenoids and isoprenoid-based biofuels are two classes of important isoprenoids. These isoprenoids have been produced microbially through metabolic engineering and synthetic biology efforts. Herein, we briefly review the engineered biosynthetic pathways in well-characterized microbial systems for the production of carotenoids and several isoprenoid-based biofuels.

  9. An integrated study to analyze soil microbial community structure and metabolic potential in two forest types.

    Zhang, Yuguang; Cong, Jing; Lu, Hui; Yang, Caiyun; Yang, Yunfeng; Zhou, Jizhong; Li, Diqiang

    2014-01-01

    Soil microbial metabolic potential and ecosystem function have received little attention owing to difficulties in methodology. In this study, we selected natural mature forest and natural secondary forest and analyzed the soil microbial community and metabolic potential combing the high-throughput sequencing and GeoChip technologies. Phylogenetic analysis based on 16S rRNA sequencing showed that one known archaeal phylum and 15 known bacterial phyla as well as unclassified phylotypes were presented in these forest soils, and Acidobacteria, Protecobacteria, and Actinobacteria were three of most abundant phyla. The detected microbial functional gene groups were related to different biogeochemical processes, including carbon degradation, carbon fixation, methane metabolism, nitrogen cycling, phosphorus utilization, sulfur cycling, etc. The Shannon index for detected functional gene probes was significantly higher (PThe regression analysis showed that a strong positive (Pthe soil microbial functional gene diversity and phylogenetic diversity. Mantel test showed that soil oxidizable organic carbon, soil total nitrogen and cellulose, glucanase, and amylase activities were significantly linked (Pthe relative abundance of corresponded functional gene groups. Variance partitioning analysis showed that a total of 81.58% of the variation in community structure was explained by soil chemical factors, soil temperature, and plant diversity. Therefore, the positive link of soil microbial structure and composition to functional activity related to ecosystem functioning was existed, and the natural secondary forest soil may occur the high microbial metabolic potential. Although the results can't directly reflect the actual microbial populations and functional activities, this study provides insight into the potential activity of the microbial community and associated feedback responses of the terrestrial ecosystem to environmental changes.

  10. Kinetic modeling of microbially-driven redox chemistry of radionuclides in subsurface environments: Coupling transport, microbial metabolism and geochemistry

    WANG,YIFENG; PAPENGUTH,HANS W.

    2000-05-04

    Microbial degradation of organic matter is a driving force in many subsurface geochemical systems, and therefore may have significant impacts on the fate of radionuclides released into subsurface environments. In this paper, the authors present a general reaction-transport model for microbial metabolism, redox chemistry, and radionuclide migration in subsurface systems. The model explicitly accounts for biomass accumulation and the coupling of radionuclide redox reactions with major biogeochemical processes. Based on the consideration that the biomass accumulation in subsurface environments is likely to achieve a quasi-steady state, they have accordingly modified the traditional microbial growth kinetic equation. They justified the use of the biogeochemical models without the explicit representation of biomass accumulation, if the interest of modeling is in the net impact of microbial reactions on geochemical processes. They then applied their model to a scenario in which an oxic water flow containing both uranium and completing organic ligands is recharged into an oxic aquifer in a carbonate formation. The model simulation shows that uranium can be reduced and therefore immobilized in the anoxic zone created by microbial degradation.

  11. Kinetic modeling of microbially-driven redox chemistry of radionuclides in subsurface environments: Coupling transport, microbial metabolism and geochemistry

    Wang, Yifeng; Papenguth, Hans W.

    2000-01-01

    Microbial degradation of organic matter is a driving force in many subsurface geochemical systems, and therefore may have significant impacts on the fate of radionuclides released into subsurface environments. In this paper, the authors present a general reaction-transport model for microbial metabolism, redox chemistry, and radionuclide migration in subsurface systems. The model explicitly accounts for biomass accumulation and the coupling of radionuclide redox reactions with major biogeochemical processes. Based on the consideration that the biomass accumulation in subsurface environments is likely to achieve a quasi-steady state, they have accordingly modified the traditional microbial growth kinetic equation. They justified the use of the biogeochemical models without the explicit representation of biomass accumulation, if the interest of modeling is in the net impact of microbial reactions on geochemical processes. They then applied their model to a scenario in which an oxic water flow containing both uranium and completing organic ligands is recharged into an oxic aquifer in a carbonate formation. The model simulation shows that uranium can be reduced and therefore immobilized in the anoxic zone created by microbial degradation

  12. Characterization of Microbial Fuel Cells at Microbially and Electrochemically Meaningful Time scales

    Ren, Zhiyong; Yan, Hengjing; Wang, Wei; Mench, Matthew M.; Regan, John M.

    2011-01-01

    The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant

  13. [Advances in metabolic engineering for the microbial production of naturally occurring terpenes-limonene and bisabolene: a mini review].

    Pang, Yaru; Hu, Zhihui; Xiao, Dongguang; Yu, Aiqun

    2018-01-25

    Limonene (C₁₀H₁₆) and bisabolene (C₁₅H₂₄) are both naturally occurring terpenes in plants. Depending on the number of C₅ units, limonene and bisabolene are recognized as representative monoterpenes and sesquiterpenes, respectively. Limonene and bisabolene are important pharmaceutical and nutraceutical products used in the prevention and treatment of cancer and many other diseases. In addition, they can be used as starting materials to produce a range of commercially valuable products, such as pharmaceuticals, nutraceuticals, cosmetics, and biofuels. The low abundance or yield of limonene and bisabolene in plants renders their isolation from plant sources non-economically viable. Isolation of limonene and bisabolene from plants also suffers from low efficiency and often requires harsh reaction conditions, prolonged reaction times, and expensive equipment cost. Recently, the rapid developments in metabolic engineering of microbes provide a promising alternative route for producing these plant natural products. Therefore, producing limonene and bisabolene by engineering microbial cells into microbial factories is becoming an attractive alternative approach that can overcome the bottlenecks, making it more sustainable, environmentally friendly and economically competitive. Here, we reviewed the status of metabolic engineering of microbes that produce limonene and bisabolene including microbial hosts, key enzymes, metabolic pathways and engineering of limonene/bisabolene biosynthesis. Furthermore, key challenges and future perspectives were discussed.

  14. Genome-based Modeling and Design of Metabolic Interactions in Microbial Communities.

    Mahadevan, Radhakrishnan; Henson, Michael A

    2012-01-01

    Biotechnology research is traditionally focused on individual microbial strains that are perceived to have the necessary metabolic functions, or the capability to have these functions introduced, to achieve a particular task. For many important applications, the development of such omnipotent microbes is an extremely challenging if not impossible task. By contrast, nature employs a radically different strategy based on synergistic combinations of different microbial species that collectively achieve the desired task. These natural communities have evolved to exploit the native metabolic capabilities of each species and are highly adaptive to changes in their environments. However, microbial communities have proven difficult to study due to a lack of suitable experimental and computational tools. With the advent of genome sequencing, omics technologies, bioinformatics and genome-scale modeling, researchers now have unprecedented capabilities to analyze and engineer the metabolism of microbial communities. The goal of this review is to summarize recent applications of genome-scale metabolic modeling to microbial communities. A brief introduction to lumped community models is used to motivate the need for genome-level descriptions of individual species and their metabolic interactions. The review of genome-scale models begins with static modeling approaches, which are appropriate for communities where the extracellular environment can be assumed to be time invariant or slowly varying. Dynamic extensions of the static modeling approach are described, and then applications of genome-scale models for design of synthetic microbial communities are reviewed. The review concludes with a summary of metagenomic tools for analyzing community metabolism and an outlook for future research.

  15. Metagenomic approach reveals microbial diversity and predictive microbial metabolic pathways in Yucha, a traditional Li fermented food.

    Zhang, Jiachao; Wang, Xiaoru; Huo, Dongxue; Li, Wu; Hu, Qisong; Xu, Chuanbiao; Liu, Sixin; Li, Congfa

    2016-08-31

    Yucha is a typical traditional fermented food of the Li population in the Hainan province of China, and it is made up of cooked rice and fresh fish. In the present study, metagenomic approach and culture-dependent technology were applied to describe the diversity of microbiota and identify beneficial microbes in the Yucha. At the genus level, Lactobacillus was the most abundant genus (43.82% of the total reads), followed by Lactococcus, Enterococcus, Vibrio, Weissella, Pediococcus, Enterobacter, Salinivibrio, Acinetobacter, Macrococcus, Kluyvera and Clostridium; this result was confirmed by q-PCR. PCoA based on Weighted UniFrac distances showed an apparent clustering pattern for Yucha samples from different locations, and Lactobacillus sakei, Lactobacillus saniviri and Staphylococcus sciuri represented OTUs according to the major identified markers. At the microbial functional level, it was observed that there was an enrichment of metabolic functional features, including amino acid and carbohydrate metabolism, which implied that the microbial metabolism in the Yucha samples tended to be vigorous. Accordingly, we further investigated the correlation between the predominant microbes and metabolic functional features. Thirteen species of Lactobacillus (147 strains) were isolated, and Lactobacillus plantarum (60 isolates) and Lactobacillus pentosus (34 isolates) were isolated from every sample.

  16. Metabolomic applications to decipher gut microbial metabolic influence in health and disease

    Francois-Pierre eMartin

    2012-04-01

    Full Text Available Dietary preferences and nutrients composition have been shown to influence human and gut microbial metabolism, which ultimately has specific effects on health and diseases’ risk. Increasingly, results from molecular biology and microbiology demonstrate the key role of the gut microbiota metabolic interface to the overall mammalian host’s health status. There is therefore raising interest in nutrition research to characterize the molecular foundations of the gut microbial mammalian cross-talk at both physiological and biochemical pathway levels. Tackling these challenges can be achieved through systems biology approaches, such as metabolomics, to underpin the highly complex metabolic exchanges between diverse biological compartments, including organs, systemic biofluids and microbial symbionts. By the development of specific biomarkers for prediction of health and disease, metabolomics is increasingly used in clinical applications as regard to disease aetiology, diagnostic stratification and potentially mechanism of action of therapeutical and nutraceutical solutions. Surprisingly, an increasing number of metabolomics investigations in pre-clinical and clinical studies based on proton nuclear magnetic resonance (1H NMR spectroscopy and mass spectrometry (MS provided compelling evidence that system wide and organ-specific biochemical processes are under the influence of gut microbial metabolism. This review aims at describing recent applications of metabolomics in clinical fields where main objective is to discern the biochemical mechanisms under the influence of the gut microbiota, with insight into gastrointestinal health and diseases diagnostics and improvement of homeostasis metabolic regulation.

  17. The Importance of Transition Metals in the Expanding Network of Microbial Metabolism in the Archean Eon

    Moore, E. K.; Jelen, B. I.; Giovannelli, D.; Prabhu, A.; Raanan, H.; Falkowski, P. G.

    2017-12-01

    Deep time changes in Earth surface redox conditions, particularly due to global oxygenation, has impacted the availability of different metals and substrates that are central in biology. Oxidoreductase proteins are molecular nanomachines responsible for all biological electron transfer processes across the tree of life. These enzymes largely contain transition metals in their active sites. Microbial metabolic pathways form a global network of electron transfer, which expanded throughout the Archean eon. Older metabolisms (sulfur reduction, methanogenesis, anoxygenic photosynthesis) accessed negative redox potentials, while later evolving metabolisms (oxygenic photosynthesis, nitrification/denitrification, aerobic respiration) accessed positive redox potentials. The incorporation of different transition metals facilitated biological innovation and the expansion of the network of microbial metabolism. Network analysis was used to examine the connections between microbial taxa, metabolic pathways, crucial metallocofactors, and substrates in deep time by incorporating biosignatures preserved in the geologic record. Nitrogen fixation and aerobic respiration have the highest level of betweenness among metabolisms in the network, indicating that the oldest metabolisms are not the most central. Fe has by far the highest betweenness among metals. Clustering analysis largely separates High Metal Bacteria (HMB), Low Metal Bacteria (LMB), and Archaea showing that simple un-weighted links between taxa, metabolism, and metals have phylogenetic relevance. On average HMB have the highest betweenness among taxa, followed by Archaea and LMB. There is a correlation between the number of metallocofactors and metabolic pathways in representative bacterial taxa, but Archaea do not follow this trend. In many cases older and more recently evolved metabolisms were clustered together supporting previous findings that proliferation of metabolic pathways is not necessarily chronological.

  18. Cathodic microbial community adaptation to the removal of chlorinated herbicide in soil microbial fuel cells.

    Li, Yue; Li, Xiaojing; Sun, Yang; Zhao, Xiaodong; Li, Yongtao

    2018-04-05

    The microbial fuel cell (MFC) that uses a solid electrode as the inexhaustible electron acceptor is an innovative remediation technology that simultaneously generates bioelectricity. Chlorinated pollutants are better metabolized by reductive dechlorination in proximity to the cathode. Here, the removal efficiency of the herbicide metolachlor (ML) increased by 262 and 176% in soil MFCs that were spiked with 10 (C10) and 20 mg/kg (C20) of ML, respectively, relative to the non-electrode controls. The bioelectricity output of the C10 and C20 increased by over two- and eightfold, respectively, compared to that of the non-ML control, with maximum current densities of 49.6 ± 2.5 (C10) and 78.9 ± 0.6 mA/m 2 (C20). Based on correlations between ML concentrations and species abundances in the MFCs, it was inferred that Azohydromonas sp., Sphingomonas sp., and Pontibacter sp. play a major role in ML removal around the cathode, with peak removal efficiencies of 56 ± 1% (C10) and 58 ± 1% (C20). Moreover, Clostridium sp., Geobacter sp., Bacillus sp., Romboutsia sp., and Terrisporobacter sp. may be electricigens or closely related microbes due to the significant positive correlation between the bioelectricity generation levels and their abundances around the anode. This study suggests that a directional adaptation of the microbial community has taken place to increase both the removal of chlorinated herbicides around the cathode and the generation of bioelectricity around the anode in bioelectrochemical remediation systems.

  19. An overview of electron acceptors in microbial fuel cells

    Ucar, Deniz; Zhang, Yifeng; Angelidaki, Irini

    2017-01-01

    Microbial fuel cells (MFC) have recently received increasing attention due to their promising potential in sustainable wastewater treatment and contaminant removal. In general, contaminants can be removed either as an electron donor via microbial catalyzed oxidization at the anode or removed at t...... acceptors (e.g., nitrate, iron, copper, perchlorate) and mediators....

  20. Connecting Mitochondria, Metabolism, and Stem Cell Fate

    Wanet, Anaïs; Arnould, Thierry; Najimi, Mustapha

    2015-01-01

    As sites of cellular respiration and energy production, mitochondria play a central role in cell metabolism. Cell differentiation is associated with an increase in mitochondrial content and activity and with a metabolic shift toward increased oxidative phosphorylation activity. The opposite occurs during reprogramming of somatic cells into induced pluripotent stem cells. Studies have provided evidence of mitochondrial and metabolic changes during the differentiation of both embryonic and somatic (or adult) stem cells (SSCs), such as hematopoietic stem cells, mesenchymal stem cells, and tissue-specific progenitor cells. We thus propose to consider those mitochondrial and metabolic changes as hallmarks of differentiation processes. We review how mitochondrial biogenesis, dynamics, and function are directly involved in embryonic and SSC differentiation and how metabolic and sensing pathways connect mitochondria and metabolism with cell fate and pluripotency. Understanding the basis of the crosstalk between mitochondria and cell fate is of critical importance, given the promising application of stem cells in regenerative medicine. In addition to the development of novel strategies to improve the in vitro lineage-directed differentiation of stem cells, understanding the molecular basis of this interplay could lead to the identification of novel targets to improve the treatment of degenerative diseases. PMID:26134242

  1. Combining microbial cultures for efficient production of electricity from butyrate in a microbial electrochemical cell

    Miceli, Joseph F.; Garcia-Peña, Ines; Parameswaran, Prathap; Torres, César I.; Krajmalnik-Brown, Rosa

    2014-01-01

    Butyrate is an important product of anaerobic fermentation; however, it is not directly used by characterized strains of the highly efficient anode respiring bacteria (ARB) Geobacter sulfurreducens in microbial electrochemical cells. By combining a butyrate-oxidizing community with a Geobacter rich culture, we generated a microbial community which outperformed many naturally derived communities found in the literature for current production from butyrate and rivaled the highest performing natural cultures in terms of current density (~11 A/m2) and Coulombic efficiency (~70%). Microbial community analyses support the shift in the microbial community from one lacking efficient ARB in the marine hydrothermal vent community to a community consisting of ~80% Geobacter in the anode biofilm. This demonstrates the successful production and adaptation of a novel microbial culture for generating electrical current from butyrate with high current density and high Coulombic efficiency, by combining two mixed micro bial cultures containing complementing biochemical pathways. PMID:25048958

  2. Photochemical alteration of organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration.

    Ward, Collin P; Nalven, Sarah G; Crump, Byron C; Kling, George W; Cory, Rose M

    2017-10-03

    In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO 2 . This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO 2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure. Using high-resolution chemical and microbial approaches, we show that rates of DOC processing by microbes are likely governed by a combination of the abundance and lability of DOC exported from land to water and produced by photochemical processes, and the capacity and timescale that microbial communities have to adapt to metabolize photo-altered DOC.The role of dissolved organic carbon (DOC) photo-alteration in the microbial respiration of DOC to CO 2 is unclear. Here, the authors show that the impact of this mechanism depends on whether photo-alteration of DOC produces or removes molecules used by native microbial communities prior to light exposure.

  3. Cell-free protein synthesis enabled rapid prototyping for metabolic engineering and synthetic biology

    Lihong Jiang

    2018-06-01

    Full Text Available Advances in metabolic engineering and synthetic biology have facilitated the manufacturing of many valuable-added compounds and commodity chemicals using microbial cell factories in the past decade. However, due to complexity of cellular metabolism, the optimization of metabolic pathways for maximal production represents a grand challenge and an unavoidable barrier for metabolic engineering. Recently, cell-free protein synthesis system (CFPS has been emerging as an enabling alternative to address challenges in biomanufacturing. This review summarizes the recent progresses of CFPS in rapid prototyping of biosynthetic pathways and genetic circuits (biosensors to speed up design-build-test (DBT cycles of metabolic engineering and synthetic biology. Keywords: Cell-free protein synthesis, Metabolic pathway optimization, Genetic circuits, Metabolic engineering, Synthetic biology

  4. Microbial physiology-based model of ethanol metabolism in subsurface sediments

    Jin, Qusheng; Roden, Eric E.

    2011-07-01

    A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

  5. Metabolic engineering of microbial competitive advantage for industrial fermentation processes.

    Shaw, A Joe; Lam, Felix H; Hamilton, Maureen; Consiglio, Andrew; MacEwen, Kyle; Brevnova, Elena E; Greenhagen, Emily; LaTouf, W Greg; South, Colin R; van Dijken, Hans; Stephanopoulos, Gregory

    2016-08-05

    Microbial contamination is an obstacle to widespread production of advanced biofuels and chemicals. Current practices such as process sterilization or antibiotic dosage carry excess costs or encourage the development of antibiotic resistance. We engineered Escherichia coli to assimilate melamine, a xenobiotic compound containing nitrogen. After adaptive laboratory evolution to improve pathway efficiency, the engineered strain rapidly outcompeted a control strain when melamine was supplied as the nitrogen source. We additionally engineered the yeasts Saccharomyces cerevisiae and Yarrowia lipolytica to assimilate nitrogen from cyanamide and phosphorus from potassium phosphite, and they outcompeted contaminating strains in several low-cost feedstocks. Supplying essential growth nutrients through xenobiotic or ecologically rare chemicals provides microbial competitive advantage with minimal external risks, given that engineered biocatalysts only have improved fitness within the customized fermentation environment. Copyright © 2016, American Association for the Advancement of Science.

  6. Heterotrophic Anodic Denitrification in Microbial Fuel Cells

    Jakub Drewnowski

    2016-06-01

    Full Text Available Nowadays, pollution caused by energy production systems is a major environmental concern. Therefore, the development of sustainable energy sources is required. Amongst others, the microbial fuel cell (MFC seems to be a possible solution because it can produce clean energy at the same time that waste is stabilized. Unfortunately, mainly due to industrial discharges, the wastes could contain nitrates, or nitrates precursors such ammonia, which could lead to lower performance in terms of electricity production. In this work, the feasibility of coupling anodic denitrification process with electricity production in MFC and the effect of the nitrates over the MFC performance were studied. During the experiments, it was observed that the culture developed in the anodic chamber of the MFC presented a significant amount of denitrificative microorganisms. The MFC developed was able to denitrify up to 4 ppm, without affecting the current density exerted, of about 1 mA/cm2. Regarding the denitrification process, it must be highlighted that the maximum denitrification rate achieved with the culture was about 60 mg·NO3−·L−1·h−1. Based on these results, it can be stated that it is possible to remove nitrates and to produce energy, without negatively affecting the electrical performance, when the nitrate concentration is low.

  7. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell.

    Timmers, Ruud A; Rothballer, Michael; Strik, David P B T B; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

    2012-04-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors.

  8. COD removal characteristics in air-cathode microbial fuel cells

    Zhang, Xiaoyuan; He, Weihua; Ren, Lijiao; Stager, Jennifer; Evans, Patrick J.; Logan, Bruce E.

    2015-01-01

    © 2014 Elsevier Ltd. Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs

  9. Design, Modeling, and Development of Microbial Cell Factories

    Kodzius, Rimantas

    2014-03-26

    Using Metagenomic analysis, computational modeling, single cell and genome editing technologies, we will express desired microbial genes and their networks in suitable hosts for mass production of energy, food, and fine chemicals.

  10. Design, Modeling, and Development of Microbial Cell Factories

    Kodzius, Rimantas; Behzad, H.; Archer, John A.C.; Bajic, Vladimir B.; Gojobori, Takashi

    2014-01-01

    Using Metagenomic analysis, computational modeling, single cell and genome editing technologies, we will express desired microbial genes and their networks in suitable hosts for mass production of energy, food, and fine chemicals.

  11. Microbial desalination cells for energy production and desalination

    Kim, Younggy; Logan, Bruce E.

    2013-01-01

    Microbial desalination cells (MDCs) are a new, energy-sustainable method for using organic matter in wastewater as the energy source for desalination. The electric potential gradient created by exoelectrogenic bacteria desalinates water by driving

  12. Microbial Fuel Cells for Organic-Contaminated Soil Remedial Applications

    Li, Xiaojing; Wang, Xin; Weng, Liping; Zhou, Qixing; Li, Yongtao

    2017-01-01

    Efficient noninvasive techniques are desired for repairing organic-contaminated soils. Bioelectrochemical technology, especially microbial fuel cells (MFCs), has been widely used to promote a polluted environmental remediation approach, and applications include wastewater, sludge, sediment, and

  13. Diagnosis of In Situ Metabolic State and Rates of Microbial Metabolism During In Situ Uranium Bioremediation with Molecular Techniques

    Lovley, Derek R. [University of Massachusetts, Amherst

    2012-11-28

    The goal of these projects was to develop molecule tools to tract the metabolic activity and physiological status of microorganisms during in situ uranium bioremediation. Such information is important in able to design improved bioremediation strategies. As summarized below, the research was highly successful with new strategies developed for estimating in situ rates of metabolism and diagnosing the physiological status of the predominant subsurface microorganisms. This is a first not only for groundwater bioremediation studies, but also for subsurface microbiology in general. The tools and approaches developed in these studies should be applicable to the study of microbial communities in a diversity of soils and sediments.

  14. Lactose Bioelectricity on a Microbial Fuel Cell System Parallel Circuit Using Lactobacillus Bulgaricus

    Putra, Adi; Nuryanto, Rahmad; Suyati, Linda

    2014-01-01

    Electrical energy needs in Indonesia is estimated to continue growing by 4.6% per year, and if there is nothing to be done to increase the production of electric energy, this figure will increase threefold by 2030. Microbial Fuel Cells (MFC) is one way to produce alternative electric energy by utilizing organic material as a substrate for bacterial metabolic activity that generate electricity. The aim of this study is to examine lactose bioelectricity in a parallel circuit MFC system using La...

  15. Detection of Metabolism Function of Microbial Community of Corpses by Biolog-Eco Method.

    Jiang, X Y; Wang, J F; Zhu, G H; Ma, M Y; Lai, Y; Zhou, H

    2016-06-01

    To detect the changes of microbial community functional diversity of corpses with different postmortem interval (PMI) and to evaluate forensic application value for estimating PMI. The cultivation of microbial community from the anal swabs of a Sus scrofa and a human corpse placed in field environment from 0 to 240 h after death was performed using the Biolog-Eco Microplate and the variations of the absorbance values were also monitored. Combined with the technology of forensic pathology and flies succession, the metabolic characteristics and changes of microbial community on the decomposed corpse under natural environment were also observed. The diversity of microbial metabolism function was found to be negatively correlated with the number of maggots in the corpses. The freezing processing had the greatest impact on average well color development value at 0 h and the impact almost disappeared after 48 h. The diversity of microbial metabolism of the samples became relatively unstable after 192 h. The principal component analysis showed that 31 carbon sources could be consolidated for 5 principal components (accumulative contribution ratio >90%).The carbon source tsquare-analysis showed that N -acetyl- D -glucosamine and L -serine were the dominant carbon sources for estimating the PMI (0=240 h) of the Sus scrofa and human corpse. The Biolog-Eco method can be used to reveal the metabolic differences of the carbon resources utilization of the microbial community on the corpses during 0-240 h after death, which could provide a new basis for estimating the PMI. Copyright© by the Editorial Department of Journal of Forensic Medicine

  16. Genome-resolved metagenomics reveals that sulfur metabolism dominates the microbial ecology of rising hydrothermal plumes

    Anantharaman, K.; Breier, J. A., Jr.; Jain, S.; Reed, D. C.; Dick, G.

    2015-12-01

    Deep-sea hydrothermal plumes occur when hot fluids from hydrothermal vents replete with chemically reduced elements and compounds like sulfide, methane, hydrogen, ammonia, iron and manganese mix with cold, oxic seawater. Chemosynthetic microbes use these reduced chemicals to power primary production and are pervasive throughout the deep sea, even at sites far removed from hydrothermal vents. Although neutrally-buoyant hydrothermal plumes have been well-studied, rising hydrothermal plumes have received little attention even though they represent an important interface in the deep-sea where microbial metabolism and particle formation processes control the transformation of important elements and impact global biogeochemical cycles. In this study, we used genome-resolved metagenomic analyses and thermodynamic-bioenergetic modeling to study the microbial ecology of rising hydrothermal plumes at five different hydrothermal vents spanning a range of geochemical gradients at the Eastern Lau Spreading Center (ELSC) in the Western Pacific Ocean. Our analyses show that differences in the geochemistry of hydrothermal vents do not manifest in microbial diversity and community composition, both of which display only minor variance across ELSC hydrothermal plumes. Microbial metabolism is dominated by oxidation of reduced sulfur species and supports a diversity of bacteria, archaea and viruses that provide intriguing insights into metabolic plasticity and virus-mediated horizontal gene transfer in the microbial community. The manifestation of sulfur oxidation genes in hydrogen and methane oxidizing organisms hints at metabolic opportunism in deep-sea microbes that would enable them to respond to varying redox conditions in hydrothermal plumes. Finally, we infer that the abundance, diversity and metabolic versatility of microbes associated with sulfur oxidation impart functional redundancy that could allow it to persist in the dynamic settings of hydrothermal plumes.

  17. Aerobic microbial metabolism of condensed thiophenes found in petroleum

    Kropp, K. G.

    1997-01-01

    The aerobic microbial degradation of 21 condensed thiophenes found in petroleum or synthetic fuels have been studied, motivated by recent research which showed that resistance to biodegradation increases with increasing methyl-substitution. The specific objective was to identify metabolites in pure cultures of aromatic hydrocarbon-degrading Pseudomonas spp. incubated in mineral medium in the presence of an aromatic growth substrate and a condensed thiophene. Over 80 metabolites of the condensed thiophenes were identified using gas chromatography analysis with an atomic emission detector. Among the metabolites identified were sulfoxides, sulfones, hydroxy- and carboxyl-substituted benzothiophenes, hydroxy-substituted dibenzothiophenes, substituted benzothiophene-2,3-diones, and 3-hydroxy-2-formylbenzothiophenes

  18. Visualization of Metabolic Interaction Networks in Microbial Communities Using VisANT 5.0.

    Brian R Granger

    2016-04-01

    Full Text Available The complexity of metabolic networks in microbial communities poses an unresolved visualization and interpretation challenge. We address this challenge in the newly expanded version of a software tool for the analysis of biological networks, VisANT 5.0. We focus in particular on facilitating the visual exploration of metabolic interaction between microbes in a community, e.g. as predicted by COMETS (Computation of Microbial Ecosystems in Time and Space, a dynamic stoichiometric modeling framework. Using VisANT's unique metagraph implementation, we show how one can use VisANT 5.0 to explore different time-dependent ecosystem-level metabolic networks. In particular, we analyze the metabolic interaction network between two bacteria previously shown to display an obligate cross-feeding interdependency. In addition, we illustrate how a putative minimal gut microbiome community could be represented in our framework, making it possible to highlight interactions across multiple coexisting species. We envisage that the "symbiotic layout" of VisANT can be employed as a general tool for the analysis of metabolism in complex microbial communities as well as heterogeneous human tissues. VisANT is freely available at: http://visant.bu.edu and COMETS at http://comets.bu.edu.

  19. Visualization of Metabolic Interaction Networks in Microbial Communities Using VisANT 5.0.

    Granger, Brian R; Chang, Yi-Chien; Wang, Yan; DeLisi, Charles; Segrè, Daniel; Hu, Zhenjun

    2016-04-01

    The complexity of metabolic networks in microbial communities poses an unresolved visualization and interpretation challenge. We address this challenge in the newly expanded version of a software tool for the analysis of biological networks, VisANT 5.0. We focus in particular on facilitating the visual exploration of metabolic interaction between microbes in a community, e.g. as predicted by COMETS (Computation of Microbial Ecosystems in Time and Space), a dynamic stoichiometric modeling framework. Using VisANT's unique metagraph implementation, we show how one can use VisANT 5.0 to explore different time-dependent ecosystem-level metabolic networks. In particular, we analyze the metabolic interaction network between two bacteria previously shown to display an obligate cross-feeding interdependency. In addition, we illustrate how a putative minimal gut microbiome community could be represented in our framework, making it possible to highlight interactions across multiple coexisting species. We envisage that the "symbiotic layout" of VisANT can be employed as a general tool for the analysis of metabolism in complex microbial communities as well as heterogeneous human tissues. VisANT is freely available at: http://visant.bu.edu and COMETS at http://comets.bu.edu.

  20. Functional Gene Diversity and Metabolic Potential of the Microbial Community in an Estuary-Shelf Environment

    Yu Wang

    2017-06-01

    Full Text Available Microbes play crucial roles in various biogeochemical processes in the ocean, including carbon (C, nitrogen (N, and phosphorus (P cycling. Functional gene diversity and the structure of the microbial community determines its metabolic potential and therefore its ecological function in the marine ecosystem. However, little is known about the functional gene composition and metabolic potential of bacterioplankton in estuary areas. The East China Sea (ECS is a dynamic marginal ecosystem in the western Pacific Ocean that is mainly affected by input from the Changjiang River and the Kuroshio Current. Here, using a high-throughput functional gene microarray (GeoChip, we analyzed the functional gene diversity, composition, structure, and metabolic potential of microbial assemblages in different ECS water masses. Four water masses determined by temperature and salinity relationship showed different patterns of functional gene diversity and composition. Generally, functional gene diversity [Shannon–Weaner’s H and reciprocal of Simpson’s 1/(1-D] in the surface water masses was higher than that in the bottom water masses. The different presence and proportion of functional genes involved in C, N, and P cycling among the bacteria of the different water masses showed different metabolic preferences of the microbial populations in the ECS. Genes involved in starch metabolism (amyA and nplT showed higher proportion in microbial communities of the surface water masses than of the bottom water masses. In contrast, a higher proportion of genes involved in chitin degradation was observed in microorganisms of the bottom water masses. Moreover, we found a higher proportion of nitrogen fixation (nifH, transformation of hydroxylamine to nitrite (hao and ammonification (gdh genes in the microbial communities of the bottom water masses compared with those of the surface water masses. The spatial variation of microbial functional genes was significantly correlated

  1. Rumen microbial communities influence metabolic phenotypes in lambs

    Morgavi, Diego P.; Rahahao-Paris, Estelle; Popova, Milka

    2015-01-01

    and the metabolic phenotype of lambs for identifying host-microbe associations and potential biomarkers of digestive functions. Twin lambs, separated in two groups after birth were exposed to practices (isolation and gavage with rumen fluid with protozoa or protozoa-depleted) that differentially restricted...

  2. Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

    Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

    2016-12-01

    Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Powering microbial electrolysis cells by capacitor circuits charged using microbial fuel cell

    Hatzell, Marta C.

    2013-05-01

    A microbial electrolysis cell (MEC) was powered by a capacitor based energy storage circuit using energy from a microbial fuel cell (MFC) to increase MEC hydrogen production rates compared to that possible by the MFC alone. To prevent voltage reversal, MFCs charged the capacitors in a parallel configuration, and then the capacitors were discharged in series to boost the voltage that was used to power the MECs. The optimal capacitance for charging was found to be ∼0.01 F for each MFC. The use of the capacitor charging system increased energy recoveries from 9 to 13%, and hydrogen production rates increased from 0.31 to 0.72 m3 m-3-day-1, compared to coupled systems without capacitors. The circuit efficiency (the ratio of the energy that was discharged to the MEC to the energy provided to the capacitor from the MFCs) was ∼90%. These results provide an improved method for linking MFCs to MECs for renewable hydrogen gas production. © 2012 Elsevier B.V. All rights reserved.

  4. Immobilization of microbial cells: A promising tool for treatment of ...

    The review articles on cell immobilization have been published since 1980 and reflect the general interest in this topic. Immobilized microbial cells create opportunities in a wide range of sectors including environmental pollution control. Compared with suspended microorganism technology, cell immobilization shows many ...

  5. Electricity generation using microbial fuel cells

    Mohan, Y.; Manoj Muthu Kumar, S.; Das, D. [Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302 (India)

    2008-01-15

    Conversion of biomass into electricity is possible using microbial fuel cells (MFCs). The present paper deals with the studies of a two-chambered salt bridge MFC using Enterobacter cloacae IIT-BT 08 in MYG medium. The effect of different electron mediators, concentration of the mediator, ionic strength (salt concentration) of the medium and the surface area of the salt-bridge in contact with the anode and cathode chambers on the power generation in MFCs are reported. In the case of methyl viologen (MV) (0.1 mM) as the electron mediator, the voltage generation was 0.4 V but no current was detected. Different concentrations of methylene blue (MB) were also studied as the mediator. A maximum voltage of 0.37 V was seen at 0.05 mM MB, whereas a maximum current and power of 56.7{mu} A and 19.2{mu} W, respectively, were observed in the case of 0.03 mM MB with a voltage of 0.34 V. The corresponding power density and current density of 9.3mW/m{sup 2} and 27.6mA/m{sup 2}, respectively, were obtained. When the surface area of the salt bridge in contact with the anode and cathode chambers was increased, a proportionate improvement in the power output from 19.2 to 708{mu} W was detected. The maximum power density and current density of 236mW/m{sup 2} and 666.7mA/m{sup 2}, respectively, which are found to be very promising for a salt bridge MFC were observed. (author)

  6. Metabolite secretion in microorganisms: the theory of metabolic overflow put to the test

    Pinu, Farhana R.; Granucci, Ninna; Daniell, James

    2018-01-01

    Introduction Microbial cells secrete many metabolites during growth, including important intermediates of the central carbon metabolism. This has not been taken into account by researchers when modeling microbial metabolism for metabolic engineering and systems biology studies. Materials and Meth...

  7. B-Cell Metabolic Remodeling and Cancer

    Franchina, Davide G.; Grusdat, Melanie; Brenner, Dirk

    2018-01-01

    Cells of the immune system display varying metabolic profiles to fulfill their functions. B lymphocytes overcome fluctuating energy challenges as they transition from the resting state and recirculation to activation, rapid proliferation, and massive antibody production. Only through a controlled...

  8. Microbial arsenic metabolism: New twists on an old poison

    Stolz, J.F.; Basu, P.; Oremland, R.S.

    2010-01-01

    Phylogenetically diverse microorganisms metabolize arsenic despite its toxicity and are part of its robust iogeochemical cycle. Respiratory arsenate reductase is a reversible enzyme, functioning in some microbes as an arsenate reductase but in others as an arsenite oxidase. As(III) can serve as an electron donor for anoxygenic photolithoautotrophy and chemolithoautotrophy. Organoarsenicals, such as the feed additive roxarsone, can be used as a source of energy, releasing inorganic arsenic.

  9. Characterization and Modeling Of Microbial Carbon Metabolism In Thawing Permafrost

    Graham, D. E.; Phelps, T. J.; Xu, X.; Carroll, S.; Jagadamma, S.; Shakya, M.; Thornton, P. E.; Elias, D. A.

    2012-12-01

    Increased annual temperatures in the Arctic are warming the surface and subsurface, resulting in thawing permafrost. Thawing exposes large pools of buried organic carbon to microbial degradation, increasing greenhouse gas generation and emission. Most global-scale land-surface models lack depth-dependent representations of carbon conversion and GHG transport; therefore they do not adequately describe permafrost thawing or microbial mineralization processes. The current work was performed to determine how permafrost thawing at moderately elevated temperatures and anoxic conditions would affect CO2 and CH4 generation, while parameterizing depth-dependent GHG production processes with respect to temperature and pH in biogeochemical models. These enhancements will improve the accuracy of GHG emission predictions and identify key biochemical and geochemical processes for further refinement. Three core samples were obtained from discontinuous permafrost terrain in Fairbanks, AK with a mean annual temperature of -3.3 °C. Each core was sectioned into surface/near surface (0-0.8 m), active layer (0.8-1.6 m), and permafrost (1.6-2.2 m) horizons, which were homogenized for physico-chemical characterization and microcosm construction. Surface samples had low pH values (6.0), low water content (18% by weight), low organic carbon (0.8%), and high C:N ratio (43). Active layer samples had higher pH values (6.4), higher water content (34%), more organic carbon (1.4%) and a lower C:N ratio (24). Permafrost samples had the highest pH (6.5), highest water content (46%), high organic carbon (2.5%) and the lowest C:N ratio (19). Most organic carbon was quantified as labile or intermediate pool versus stable pool in each sample, and all samples had low amounts of carbonate. Surface layer microcosms, containing 20 g sediment in septum-sealed vials, were incubated under oxic conditions, while similar active and permafrost layer samples were anoxic. These microcosms were incubated at -2

  10. Simultaneous efficient removal of oxyfluorfen with electricity generation in a microbial fuel cell and its microbial community analysis.

    Zhang, Qinghua; Zhang, Lei; Wang, Han; Jiang, Qinrui; Zhu, Xiaoyu

    2018-02-01

    The performance of a microbial fuel cell (MFC) to degrade oxyfluorfen was investigated. Approximately 77% of 50 mg/L oxyfluorfen was degraded within 24 h by anodic biofilm. The temperature, pH, and initial oxyfluorfen concentration had a significant effect on oxyfluorfen degrading, and a maximum degradation rate of 94.95% could theoretically be achieved at 31.96 °C, a pH of 7.65, and an initial oxyfluorfen concentration of 120.05 mg/L. Oxyfluorfen was further catabolized through various microbial metabolism pathways. Moreover, the anodic biofilm exhibited multiple catabolic capacities to 4-nitrophenol, chloramphenicol, pyraclostrobin, and sulfamethoxazole. Microbial community analysis indicated that functional bacteria Arcobacter, Acinetobacter, Azospirillum, Azonexus, and Comamonas were the predominant genera in the anodic biofilm. In terms of the efficient removal of various organic compounds and energy recovery, the MFC seemed to be a promising approach for the treatment of environmental contaminants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. MATHEMATICAL MODELING OF THE ELECTRIC CURRENT GENERATION IN A MICROBIAL FUEL CELL INOCULATED WITH MARINE SEDIMENT

    J. T. Teleken

    Full Text Available Abstract Microbial fuel cells (MFC are electrochemical devices that utilize the ability of some microorganisms to oxidize organic matter and transfer electrons resulting from their metabolism to an insoluble acceptor. The goal of the present study was to model the kinetics of electrical current generation from an MFC inoculated with marine sediment. For this purpose, a differential equation system was used, including the Nernst-Monod relationship and Ohm's Law, to describe the microbial metabolism and the mechanism of extracellular electron transfer (EET, respectively. The experimental data obtained by cyclic voltammetry analysis were properly described by the model. It was concluded that marine microorganisms preferably use a direct mechanism of EET by means of nanowires to establish the electrochemical contact with the anode. The mathematical modeling could help understand MFC operation and, consequently, contribute to improving power generation from this source.

  12. Generation of Electricity and Analysis of Microbial Communities in Wheat Straw Biomass-Powered Microbial Fuel Cells

    Zhang, Yifeng; Min, Booki; Huang, L.

    2009-01-01

    Electricity generation from wheat straw hydrolysate and the microbial ecology of electricity producing microbial communities developed in two chamber microbial fuel cells (MFCs) were investigated. Power density reached 123 mW/m2 with an initial hydrolysate concentration of 1000 mg-COD/L while...

  13. Genome-centric resolution of microbial diversity, metabolism and interactions in anaerobic digestion.

    Vanwonterghem, Inka; Jensen, Paul D; Rabaey, Korneel; Tyson, Gene W

    2016-09-01

    Our understanding of the complex interconnected processes performed by microbial communities is hindered by our inability to culture the vast majority of microorganisms. Metagenomics provides a way to bypass this cultivation bottleneck and recent advances in this field now allow us to recover a growing number of genomes representing previously uncultured populations from increasingly complex environments. In this study, a temporal genome-centric metagenomic analysis was performed of lab-scale anaerobic digesters that host complex microbial communities fulfilling a series of interlinked metabolic processes to enable the conversion of cellulose to methane. In total, 101 population genomes that were moderate to near-complete were recovered based primarily on differential coverage binning. These populations span 19 phyla, represent mostly novel species and expand the genomic coverage of several rare phyla. Classification into functional guilds based on their metabolic potential revealed metabolic networks with a high level of functional redundancy as well as niche specialization, and allowed us to identify potential roles such as hydrolytic specialists for several rare, uncultured populations. Genome-centric analyses of complex microbial communities across diverse environments provide the key to understanding the phylogenetic and metabolic diversity of these interactive communities. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Genome-driven evolutionary game theory helps understand the rise of metabolic interdependencies in microbial communities.

    Zomorrodi, Ali R; Segrè, Daniel

    2017-11-16

    Metabolite exchanges in microbial communities give rise to ecological interactions that govern ecosystem diversity and stability. It is unclear, however, how the rise of these interactions varies across metabolites and organisms. Here we address this question by integrating genome-scale models of metabolism with evolutionary game theory. Specifically, we use microbial fitness values estimated by metabolic models to infer evolutionarily stable interactions in multi-species microbial "games". We first validate our approach using a well-characterized yeast cheater-cooperator system. We next perform over 80,000 in silico experiments to infer how metabolic interdependencies mediated by amino acid leakage in Escherichia coli vary across 189 amino acid pairs. While most pairs display shared patterns of inter-species interactions, multiple deviations are caused by pleiotropy and epistasis in metabolism. Furthermore, simulated invasion experiments reveal possible paths to obligate cross-feeding. Our study provides genomically driven insight into the rise of ecological interactions, with implications for microbiome research and synthetic ecology.

  15. Solar energy powered microbial fuel cell with a reversible bioelectrode.

    Strik, David P B T B; Hamelers, Hubertus V M; Buisman, Cees J N

    2010-01-01

    The solar energy powered microbial fuel cell is an emerging technology for electricity generation via electrochemically active microorganisms fueled by solar energy via in situ photosynthesized metabolites from algae, cyanobacteria, or living higher plants. A general problem with microbial fuel cells is the pH membrane gradient which reduces cell voltage and power output. This problem is caused by acid production at the anode, alkaline production at the cathode, and the nonspecific proton exchange through the membrane. Here we report a solution for a new kind of solar energy powered microbial fuel cell via development of a reversible bioelectrode responsible for both biocatalyzed anodic and cathodic electron transfer. Anodic produced protons were used for the cathodic reduction reaction which held the formation of a pH membrane gradient. The microbial fuel cell continuously generated electricity and repeatedly reversed polarity dependent on aeration or solar energy exposure. Identified organisms within biocatalyzing biofilm of the reversible bioelectrode were algae, (cyano)bacteria and protozoa. These results encourage application of solar energy powered microbial fuel cells.

  16. Imaging microbial metal metabolism in situ under conditions of the deep-sea hydrothermal vents

    Oger, P. M.; Daniel, I.; Simionovici, A.; Picard, A.

    2006-12-01

    High-pressure biotopes are the most widely spread biotopes on Earth. They represent one possible location for the origin of life. They also share striking similarities with extraterrestrial biotopes such as those postulated for Europe or Mars. In absence of light, dissimilatory reduction of metals (DMR) is fueling the ecosystem. Monitoring the metabolism of the deep-sea hydrothermal vent microbial fauna under P, T and chemical conditions relevant to their isolation environment can be difficult because of the confinement and because most spectroscopic probes do not sense metallic ions in solution. We demonstrated the possibility to use Xray spectroscopy to monitor the speciation of metallic species in solution. Experiments were performed at The ESRF using Selenium (Se) detoxification by Agrobacterium tumefaciens as an analog of DMR. The reduction of Se from selenite to the metal was monitored by a combiantion of two Xray spectroscopic techniques (XANES and μXRF). Cells were incubated in the low pressure DAC in growth medium supplemented with 5mM Selenite and incubated under pressures up to 60 Mpa at 30°C for 24h. The evolution of the speciation can be easily monitored and the concentration of each Se species determined from the Xray spectra by linear combinations of standard spectra. Selenite is transformed by the bacterium into a mixture of metal Se and methylated Se after 24 hours. Se detoxification is observed in situ up to at least 25 MPa. The technique, developped for Se can be adapted to monitor other elements more relevant to DMR such as As, Fe or S, which should allow to monitor in situ under controlled pressure and temperature the metabolism of vent organisms. It is also amenable to the monitoring of toxic metals. Xray spectroscopy and the lpDAC are compatible with other spectroscopic techniques, such as Raman, UV or IR spectroscopies, allowing to probe other metabolic activities. Hence, enlarging the range of metabolic information that can be obtained in

  17. Voltage balancing strategies for serial connection of microbial fuel cells

    Khaled, Firas; Ondel, Olivier; Allard, Bruno; Buret, François

    2015-07-01

    The microbial fuel cell (MFC) converts electrochemically organic matter into electricity by means of metabolisms of bacteria. The MFC power output is limited by low voltage and low current characteristics in the range of microwatts or milliwatts per litre. In order to produce a sufficient voltage level (>1.5 V) and sufficient power to supply real applications such as autonomous sensors, it is necessary to either scale-up one single unit or to connect multiple units together. Many topologies of connection are possible as the serial association to improve the output voltage, or the parallel connection to improve the output current or the series/parallel connection to step-up both voltage and current. The association of MFCs in series is a solution to increase the voltage to an acceptable value and to mutualize the unit's output power. The serial association of a large number of MFCs presents several issues. The first one is the hydraulic coupling among MFCs when they share the same substrate. The second one is the dispersion between generators that lead to a non-optimal stack efficiency because the maximum power point (MPP) operation of all MFCs is not permitted. Voltage balancing is a solution to compensate non-uniformities towards MPP. This paper presents solutions to improve the efficiency of a stack of serially connected MFCs through a voltage-balancing circuit. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014)", edited by Adel Razek

  18. Summer investigations into the metabolic diversity of the microbial world

    Breznak, J.; Dworkin, M.

    1993-05-17

    The philosophy of the course described here is to underscore the essence of microbiology which is diversity>: diversity of morphology and cellular development, behavior, and metabolic and physiological functions. Emphasis is on microbes other than those customarily covered in conventional microbiology courses and includes: the archaebacteria, extremophiles, and array of obligate anaerobes, various phototrophs, and those microbes exhibiting complex developmental cycles. Also included are microbes carrying out a variety of transformations of organic and inorganic compounds, as well as those which normally occur in symbiotic association with other microbes or with higher forms of life.

  19. Carbon and nitrogen assimilation in deep subseafloor microbial cells

    Morono, Yuki; Terada, Takeshi; Nishizawa, Manabu; Ito, Motoo; Hillion, François; Takahata, Naoto; Sano, Yuji; Inagaki, Fumio

    2011-01-01

    Remarkable numbers of microbial cells have been observed in global shallow to deep subseafloor sediments. Accumulating evidence indicates that deep and ancient sediments harbor living microbial life, where the flux of nutrients and energy are extremely low. However, their physiology and energy requirements remain largely unknown. We used stable isotope tracer incubation and nanometer-scale secondary ion MS to investigate the dynamics of carbon and nitrogen assimilation activities in individua...

  20. Microbial electrolysis kinetics and cell design

    Sleutels, T.H.J.A.

    2010-01-01

    Large amounts of hydrogen are produced worldwide, which are nearly all from fossil origin. Use of biomass instead of fossil fuels to produce hydrogen can contribute to a reduction of greenhouse gas emissions. Therefore, the hydrogen has to be produced at high yield and efficiency. A Microbial

  1. A Status Report on the Global Research in Microbial Metabolic Engineering

    Joe, Min Ho; Lim, Sang Yong; Kim, Dong Ho

    2008-09-15

    Biotechnology industry is now a global 'Mega-Trend' and metabolic engineering technology has important role is this area. Therefore, many countries has made efforts in this field to produce top value added bio-products efficiently using microorganisms. It has been applied to increase the production of chemicals that are already produced by the host organism, to produce desired chemical substances from less expensive feedstock, and to generate products that are new to the host organism. Recent experimental advances, the so-called '-omics' technologies, mainly functional genomics, proteomics and metabolomics, have enabled wholesale generation of new genomic, transcriptomic, proteomic, and metabolomic data. This report provides the insights of the integrated view of metabolism generated by metabolic engineering for biotechnological applications of microbial metabolic engineering.

  2. A Status Report on the Global Research in Microbial Metabolic Engineering

    Joe, Min Ho; Lim, Sang Yong; Kim, Dong Ho

    2008-09-01

    Biotechnology industry is now a global 'Mega-Trend' and metabolic engineering technology has important role is this area. Therefore, many countries has made efforts in this field to produce top value added bio-products efficiently using microorganisms. It has been applied to increase the production of chemicals that are already produced by the host organism, to produce desired chemical substances from less expensive feedstock, and to generate products that are new to the host organism. Recent experimental advances, the so-called '-omics' technologies, mainly functional genomics, proteomics and metabolomics, have enabled wholesale generation of new genomic, transcriptomic, proteomic, and metabolomic data. This report provides the insights of the integrated view of metabolism generated by metabolic engineering for biotechnological applications of microbial metabolic engineering

  3. A Status Report on the Global Research in Microbial Metabolic Engineering

    Joe, Min Ho; Lim, Sang Yong; Kim, Dong Ho

    2008-09-15

    Biotechnology industry is now a global 'Mega-Trend' and metabolic engineering technology has important role is this area. Therefore, many countries has made efforts in this field to produce top value added bio-products efficiently using microorganisms. It has been applied to increase the production of chemicals that are already produced by the host organism, to produce desired chemical substances from less expensive feedstock, and to generate products that are new to the host organism. Recent experimental advances, the so-called '-omics' technologies, mainly functional genomics, proteomics and metabolomics, have enabled wholesale generation of new genomic, transcriptomic, proteomic, and metabolomic data. This report provides the insights of the integrated view of metabolism generated by metabolic engineering for biotechnological applications of microbial metabolic engineering.

  4. Effect of silver nanoparticles on growth performance, metabolism and microbial profile of broiler chickens

    Pineda, Lane Manalili; Chwalibog, André; Sawosz, Ewa

    2012-01-01

    and intestinal content were collected to evaluate the effects of AgNano on plasma concentration of immunoglobulins and the intestinal microflora, respectively. The provision of water solutions containing different concentrations of AgNano had no effect on postnatal growth performance and the energy metabolism...... (IgG) in the blood plasma of broilers supplemented with AgNano decreased at day 36 (p = 0.012). The results demonstrated that AgNano affects N utilisation and plasma IgG concentration; however, it does not influence the microbial populations in the digestive tract, the energy metabolism and growth...

  5. Metal availability and the expanding network of microbial metabolisms in the Archaean eon

    Moore, Eli K.; Jelen, Benjamin I.; Giovannelli, Donato; Raanan, Hagai; Falkowski, Paul G.

    2017-09-01

    Life is based on energy gained by electron-transfer processes; these processes rely on oxidoreductase enzymes, which often contain transition metals in their structures. The availability of different metals and substrates has changed over the course of Earth's history as a result of secular changes in redox conditions, particularly global oxygenation. New metabolic pathways using different transition metals co-evolved alongside changing redox conditions. Sulfur reduction, sulfate reduction, methanogenesis and anoxygenic photosynthesis appeared between about 3.8 and 3.4 billion years ago. The oxidoreductases responsible for these metabolisms incorporated metals that were readily available in Archaean oceans, chiefly iron and iron-sulfur clusters. Oxygenic photosynthesis appeared between 3.2 and 2.5 billion years ago, as did methane oxidation, nitrogen fixation, nitrification and denitrification. These metabolisms rely on an expanded range of transition metals presumably made available by the build-up of molecular oxygen in soil crusts and marine microbial mats. The appropriation of copper in enzymes before the Great Oxidation Event is particularly important, as copper is key to nitrogen and methane cycling and was later incorporated into numerous aerobic metabolisms. We find that the diversity of metals used in oxidoreductases has increased through time, suggesting that surface redox potential and metal incorporation influenced the evolution of metabolism, biological electron transfer and microbial ecology.

  6. Development of biologically modified anodes for energy harvesting using microbial fuel cells

    Sumner, James J.; Ganguli, Rahul; Chmelka, Brad

    2012-06-01

    Biological fuel cells hold promise as an alternative energy source to batteries for unattended ground sensor applications due to the fact that they can be extremely long lived. This lifetime can be extended over batteries by scavenging fuel from the deployed environment. Microbial fuel cells (MFC) are one class of such sources that produce usable energy from small organic compounds (i.e. sugars, alcohols, organic acids, and biopolymers) which can be easily containerized or scavenged from the environment. The use of microorganisms as the anodic catalysts is what makes these systems unique from other biofuel cell designs. One of the main drawbacks of engineering a sensor system powered by an MFC is that power densities and current flux are extremely low in currently reported systems. The power density is limited by the mass transfer of the fuel source to the catalyst, the metabolism of the microbial catalysts and the electron transfer from the organism to the anode. This presentation will focus on the development of a new style of microbially-modified anodes which will increase power density to a level where a practical power source can be engineered. This is being achieved by developing a three dimensional matrix as an artificial, conductive biofilm. These artificial biofilms will allow the capture of a consortium of microbes designed for efficient metabolism of the available fuel source. Also it will keep the microbes close to the electrode allowing ready access by fuel and providing a low resistance passage of the liberated electrons from fuel oxidation.

  7. A bioenergetics-kinetics coupled modeling study on subsurface microbial metabolism in a field biostimulation experiment

    Jin, Q.; Zheng, Z.; Zhu, C.

    2006-12-01

    Microorganisms in nature conserve energy by catalyzing various geochemical reactions. To build a quantitative relationship between geochemical conditions and metabolic rates, we propose a bioenergetics-kinetics coupled modeling approach. This approach describes microbial community as a metabolic network, i.e., fermenting microbes degrade organic substrates while aerobic respirer, nitrate reducer, metal reducer, sulfate reducer, and methanogen consume the fermentation products. It quantifies the control of substrate availability and biological energy conservation on the metabolic rates using thermodynamically consistent rate laws. We applied this simulation approach to study the progress of microbial metabolism during a field biostimulation experiment conducted in Oak Ridge, Tennessee. In the experiment, ethanol was injected into a monitoring well and groundwater was sampled to monitor changes in the chemistry. With time, concentrations of ethanol and SO42- decreased while those of NH4+, Fe2+, and Mn2+ increased. The simulation results fitted well to the observation, indicating simultaneous ethanol degradation and terminal electron accepting processes. The rates of aerobic respiration and denitrification were mainly controlled by substrate concentrations while those of ethanol degradation, sulfate reduction, and methanogenesis were controlled dominantly by the energy availability. The simulation results suggested two different microbial growth statuses in the subsurface. For the functional groups with significant growth, variations with time in substrate concentrations demonstrated a typical S curve. For the groups without significant growth, initial decreases in substrate concentrations were linear with time. Injecting substrates followed by monitoring environmental chemistry therefore provides a convenient approach to characterize microbial growth in the subsurface where methods for direct observation are currently unavailable. This research was funded by the

  8. Electronic Nose Technology to Measure Soil Microbial Activity and Classify Soil Metabolic Status

    Fabrizio De Cesare; Elena Di Mattia; Simone Pantalei; Emiliano Zampetti; Vittorio Vinciguerra; Antonella Macagnano

    2011-01-01

    The electronic nose (E-nose) is a sensing technology that has been widely used to monitor environments in the last decade. In the present study, the capability of an E-nose, in combination with biochemical and microbiological techniques, of both detecting the microbial activity and estimating the metabolic status of soil ecosystems, was tested by measuring on one side respiration, enzyme activities and growth of bacteria in natural but simplified soil ecosystems over 23 days of incubation thr...

  9. Stimulating soil microorganisms for mineralizing the herbicide isoproturon by means of microbial electroremediating cells.

    Rodrigo Quejigo, Jose; Dörfler, Ulrike; Schroll, Reiner; Esteve-Núñez, Abraham

    2016-05-01

    The absence of suitable terminal electron acceptors (TEA) in soil might limit the oxidative metabolism of environmental microbial populations. Microbial electroremediating cells (MERCs) consist in a variety of bioelectrochemical devices that aim to overcome electron acceptor limitation and maximize metabolic oxidation with the purpose of enhancing the biodegradation of a pollutant in the environment. The objective of this work was to use MERCs principles for stimulating soil bacteria to achieve the complete biodegradation of the herbicide (14) C-isoproturon (IPU) to (14) CO(2) in soils. Our study concludes that using electrodes at a positive potential [+600 mV (versus Ag/AgCl)] enhanced the mineralization by 20-fold respect the electrode-free control. We also report an overall profile of the (14) C-IPU metabolites and a (14) C mass balance in response to the different treatments. The remarkable impact of electrodes on the microbial activity of natural communities suggests a promising future for this emerging environmental technology that we propose to name bioelectroventing. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  10. Glutathione Primes T Cell Metabolism for Inflammation

    Mak, Tak W.; Grusdat, Melanie; Duncan, Gordon S.

    2017-01-01

    the activation of mammalian target of rapamycin-1 (mTOR) and expression of NFAT and Myc transcription factors, abrogating the energy utilization and Myc-dependent metabolic reprogramming that allows activated T cells to switch to glycolysis and glutaminolysis. In vivo, T-cell-specific ablation of murine Gclc...

  11. Batteryless, wireless sensor powered by a sediment microbial fuel cell.

    Donovan, Conrad; Dewan, Alim; Heo, Deukhyoun; Beyenal, Haluk

    2008-11-15

    Sediment microbial fuel cells (SMFCs) are considered to be an alternative renewable power source for remote monitoring. There are two main challenges to using SMFCs as power sources: 1) a SMFC produces a low potential at which most sensor electronics do not operate, and 2) a SMFC cannot provide continuous power, so energy from the SMFC must be stored and then used to repower sensor electronics intermittently. In this study, we developed a SMFC and a power management system (PMS) to power a batteryless, wireless sensor. A SMFC operating with a microbial anode and cathode, located in the Palouse River, Pullman, Washington, U.S.A., was used to demonstrate the utility of the developed system. The designed PMS stored microbial energy and then started powering the wireless sensor when the SMFC potential reached 320 mV. It continued powering until the SMFC potential dropped below 52 mV. The system was repowered when the SMFC potential increased to 320 mV, and this repowering continued as long as microbial reactions continued. We demonstrated that a microbial fuel cell with a microbial anode and cathode can be used as an effective renewable power source for remote monitoring using custom-designed electronics.

  12. Graphene-Based Flexible Micrometer-Sized Microbial Fuel Cell

    Mink, Justine E.

    2013-10-23

    Microbial fuel cells harvest electrical energy produced by bacteria during the natural decomposition of organic matter. We report a micrometer-sized microbial fuel cell that is able to generate nanowatt-scale power from microliters of liquids. The sustainable design is comprised of a graphene anode, an air cathode, and a polymer-based substrate platform for flexibility. The graphene layer was grown on a nickel thin film by using chemical vapor deposition at atmospheric pressure. Our demonstration provides a low-cost option to generate useful power for lab-on-chip applications and could be promising to rapidly screen and scale up microbial fuel cells for water purification without consuming excessive power (unlike other water treatment technologies).

  13. Microbial electrosynthesis of hydrogen peroxide in microbial reverse-electrodialysis electrolysis cell

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    Microbial reverse-electrodialysis electrolysis cell (MREC) as a novel type of microbial electrochemical technologies has been proposed to produce H2 and CH4. In this study, we developed MREC to produce the strong oxidant H2O2. In the MREC, electrical potential generated by the exoelectrogens...... and the salinity-gradient between sea water and river water were utilized to drive the high-rate H2O2 production without external power supply. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of high and low concentration solution were investigated. The optimal H2O2 production were...

  14. Improved genome recovery and integrated cell-size analyses of individual uncultured microbial cells and viral particles.

    Stepanauskas, Ramunas; Fergusson, Elizabeth A; Brown, Joseph; Poulton, Nicole J; Tupper, Ben; Labonté, Jessica M; Becraft, Eric D; Brown, Julia M; Pachiadaki, Maria G; Povilaitis, Tadas; Thompson, Brian P; Mascena, Corianna J; Bellows, Wendy K; Lubys, Arvydas

    2017-07-20

    Microbial single-cell genomics can be used to provide insights into the metabolic potential, interactions, and evolution of uncultured microorganisms. Here we present WGA-X, a method based on multiple displacement amplification of DNA that utilizes a thermostable mutant of the phi29 polymerase. WGA-X enhances genome recovery from individual microbial cells and viral particles while maintaining ease of use and scalability. The greatest improvements are observed when amplifying high G+C content templates, such as those belonging to the predominant bacteria in agricultural soils. By integrating WGA-X with calibrated index-cell sorting and high-throughput genomic sequencing, we are able to analyze genomic sequences and cell sizes of hundreds of individual, uncultured bacteria, archaea, protists, and viral particles, obtained directly from marine and soil samples, in a single experiment. This approach may find diverse applications in microbiology and in biomedical and forensic studies of humans and other multicellular organisms.Single-cell genomics can be used to study uncultured microorganisms. Here, Stepanauskas et al. present a method combining improved multiple displacement amplification and FACS, to obtain genomic sequences and cell size information from uncultivated microbial cells and viral particles in environmental samples.

  15. Influence of Wastewater Discharge on the Metabolic Potential of the Microbial Community in River Sediments.

    Li, Dong; Sharp, Jonathan O; Drewes, Jörg E

    2016-01-01

    To reveal the variation of microbial community functions during water filtration process in river sediments, which has been utilized widely in natural water treatment systems, this study investigates the influence of municipal wastewater discharge to streams on the phylotype and metabolic potential of the microbiome in upstream and particularly various depths of downstream river sediments. Cluster analyses based on both microbial phylogenetic and functional data collectively revealed that shallow upstream sediments grouped with those from deeper subsurface downstream regions. These sediment samples were distinct from those found in shallow downstream sediments. Functional genes associated with carbohydrate, xenobiotic, and certain amino acid metabolisms were overrepresented in upstream and deep downstream samples. In contrast, the more immediate contact with wastewater discharge in shallow downstream samples resulted in an increase in the relative abundance of genes associated with nitrogen, sulfur, purine and pyrimidine metabolisms, as well as restriction-modification systems. More diverse bacterial phyla were associated with upstream and deep downstream sediments, mainly including Actinobacteria, Planctomycetes, and Firmicutes. In contrast, in shallow downstream sediments, genera affiliated with Betaproteobacteria and Gammaproteobacteria were enriched with putative functions that included ammonia and sulfur oxidation, polyphosphate accumulation, and methylotrophic bacteria. Collectively, these results highlight the enhanced capabilities of microbial communities residing in deeper stream sediments for the transformation of water contaminants and thus provide a foundation for better design of natural water treatment systems to further improve the removal of contaminants.

  16. Genome-scale modelling of microbial metabolism with temporal and spatial resolution.

    Henson, Michael A

    2015-12-01

    Most natural microbial systems have evolved to function in environments with temporal and spatial variations. A major limitation to understanding such complex systems is the lack of mathematical modelling frameworks that connect the genomes of individual species and temporal and spatial variations in the environment to system behaviour. The goal of this review is to introduce the emerging field of spatiotemporal metabolic modelling based on genome-scale reconstructions of microbial metabolism. The extension of flux balance analysis (FBA) to account for both temporal and spatial variations in the environment is termed spatiotemporal FBA (SFBA). Following a brief overview of FBA and its established dynamic extension, the SFBA problem is introduced and recent progress is described. Three case studies are reviewed to illustrate the current state-of-the-art and possible future research directions are outlined. The author posits that SFBA is the next frontier for microbial metabolic modelling and a rapid increase in methods development and system applications is anticipated. © 2015 Authors; published by Portland Press Limited.

  17. Influence of Wastewater Discharge on the Metabolic Potential of the Microbial Community in River Sediments

    Li, Dong

    2015-09-24

    To reveal the variation of microbial community functions during water filtration process in river sediments, which has been utilized widely in natural water treatment systems, this study investigates the influence of municipal wastewater discharge to streams on the phylotype and metabolic potential of the microbiome in upstream and particularly various depths of downstream river sediments. Cluster analyses based on both microbial phylogenetic and functional data collectively revealed that shallow upstream sediments grouped with those from deeper subsurface downstream regions. These sediment samples were distinct from those found in shallow downstream sediments. Functional genes associated with carbohydrate, xenobiotic, and certain amino acid metabolisms were overrepresented in upstream and deep downstream samples. In contrast, the more immediate contact with wastewater discharge in shallow downstream samples resulted in an increase in the relative abundance of genes associated with nitrogen, sulfur, purine and pyrimidine metabolisms, as well as restriction–modification systems. More diverse bacterial phyla were associated with upstream and deep downstream sediments, mainly including Actinobacteria, Planctomycetes, and Firmicutes. In contrast, in shallow downstream sediments, genera affiliated with Betaproteobacteria and Gammaproteobacteria were enriched with putative functions that included ammonia and sulfur oxidation, polyphosphate accumulation, and methylotrophic bacteria. Collectively, these results highlight the enhanced capabilities of microbial communities residing in deeper stream sediments for the transformation of water contaminants and thus provide a foundation for better design of natural water treatment systems to further improve the removal of contaminants. © 2015, Springer Science+Business Media New York.

  18. Metagenomic analysis of an ecological wastewater treatment plant's microbial communities and their potential to metabolize pharmaceuticals.

    Balcom, Ian N; Driscoll, Heather; Vincent, James; Leduc, Meagan

    2016-01-01

    Pharmaceuticals and other micropollutants have been detected in drinking water, groundwater, surface water, and soil around the world. Even in locations where wastewater treatment is required, they can be found in drinking water wells, municipal water supplies, and agricultural soils. It is clear conventional wastewater treatment technologies are not meeting the challenge of the mounting pressures on global freshwater supplies. Cost-effective ecological wastewater treatment technologies have been developed in response. To determine whether the removal of micropollutants in ecological wastewater treatment plants (WWTPs) is promoted by the plant-microbe interactions, as has been reported for other recalcitrant xenobiotics, biofilm microbial communities growing on the surfaces of plant roots were profiled by whole metagenome sequencing and compared to the microbial communities residing in the wastewater. In this study, the concentrations of pharmaceuticals and personal care products (PPCPs) were quantified in each treatment tank of the ecological WWTP treating human wastewater at a highway rest stop and visitor center in Vermont. The concentrations of detected PPCPs were substantially greater than values reported for conventional WWTPs likely due to onsite recirculation of wastewater. The greatest reductions in PPCPs concentrations were observed in the anoxic treatment tank where Bacilli dominated the biofilm community. Benzoate degradation was the most abundant xenobiotic metabolic category identified throughout the system. Collectively, the microbial communities residing in the wastewater were taxonomically and metabolically more diverse than the immersed plant root biofilm. However, greater heterogeneity and higher relative abundances of xenobiotic metabolism genes was observed for the root biofilm.

  19. Actionable Metabolic Pathways in Heart Failure and Cancer—Lessons From Cancer Cell Metabolism

    Anja Karlstaedt

    2018-06-01

    Full Text Available Recent advances in cancer cell metabolism provide unprecedented opportunities for a new understanding of heart metabolism and may offer new approaches for the treatment of heart failure. Key questions driving the cancer field to understand how tumor cells reprogram metabolism and to benefit tumorigenesis are also applicable to the heart. Recent experimental and conceptual advances in cancer cell metabolism provide the cardiovascular field with the unique opportunity to target metabolism. This review compares cancer cell metabolism and cardiac metabolism with an emphasis on strategies of cellular adaptation, and how to exploit metabolic changes for therapeutic benefit.

  20. Microbial catabolic activities are naturally selected by metabolic energy harvest rate.

    González-Cabaleiro, Rebeca; Ofiţeru, Irina D; Lema, Juan M; Rodríguez, Jorge

    2015-12-01

    The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate.

  1. Microbially-reduced graphene scaffolds to facilitate extracellular electron transfer in microbial fuel cells.

    Yuan, Yong; Zhou, Shungui; Zhao, Bo; Zhuang, Li; Wang, Yueqiang

    2012-07-01

    A one-pot method is exploited by adding graphene oxide (GO) and acetate into an microbial fuel cell (MFC) in which GO is microbially reduced, leading to in situ construction of a bacteria/graphene network in the anode. The obtained microbially reduced graphene (MRG) exhibits comparable conductivity and physical characteristics to the chemically reduced graphene. Electrochemical measurements reveal that the number of exoelectrogens involved in extracellular electron transfer (EET) to the solid electrode, increases due to the presence of graphene scaffolds, and the EET is facilitated in terms of electron transfer kinetics. As a result, the maximum power density of the MFC is enhanced by 32% (from 1440 to 1905 mW m(-2)) and the coulombic efficiency is improved by 80% (from 30 to 54%). The results demonstrate that the construction of the bacteria/graphene network is an effective alternative to improve the MFC performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism.

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone; Dopson, Mark

    2017-08-09

    A key characteristic of eutrophication in coastal seas is the expansion of hypoxic bottom waters, often referred to as 'dead zones'. One proposed remediation strategy for coastal dead zones in the Baltic Sea is to mix the water column using pump stations, circulating oxygenated water to the sea bottom. Although microbial metabolism in the sediment surface is recognized as key in regulating bulk chemical fluxes, it remains unknown how the microbial community and its metabolic processes are influenced by shifts in oxygen availability. Here, coastal Baltic Sea sediments sampled from oxic and anoxic sites, plus an intermediate area subjected to episodic oxygenation, were experimentally exposed to oxygen shifts. Chemical, 16S rRNA gene, metagenomic, and metatranscriptomic analyses were conducted to investigate changes in chemistry fluxes, microbial community structure, and metabolic functions in the sediment surface. Compared to anoxic controls, oxygenation of anoxic sediment resulted in a proliferation of bacterial populations in the facultative anaerobic genus Sulfurovum that are capable of oxidizing toxic sulfide. Furthermore, the oxygenated sediment had higher amounts of RNA transcripts annotated as sqr, fccB, and dsrA involved in sulfide oxidation. In addition, the importance of cryptic sulfur cycling was highlighted by the oxidative genes listed above as well as dsvA, ttrB, dmsA, and ddhAB that encode reductive processes being identified in anoxic and intermediate sediments turned oxic. In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic matter degradation. These novel data emphasize that genetic expression analyses has the power to identify key molecular mechanisms that regulate microbial community responses

  3. Cell signalling and phospholipid metabolism

    Boss, W.F.

    1990-01-01

    These studies explored whether phosphoinositide (PI) has a role in plants analogous to its role in animal cells. Although no parallel activity of PI in signal transduction was found in plant cells, activity of inositol phospholipid kinase was found to be modulated by light and by cell wall degrading enzymes. These studies indicate a major role for inositol phospholipids in plant growth and development as membrane effectors but not as a source of second messengers.

  4. Central role of the cell in microbial ecology.

    Zengler, Karsten

    2009-12-01

    Over the last few decades, advances in cultivation-independent methods have significantly contributed to our understanding of microbial diversity and community composition in the environment. At the same time, cultivation-dependent methods have thrived, and the growing number of organisms obtained thereby have allowed for detailed studies of their physiology and genetics. Still, most microorganisms are recalcitrant to cultivation. This review not only conveys current knowledge about different isolation and cultivation strategies but also discusses what implications can be drawn from pure culture work for studies in microbial ecology. Specifically, in the light of single-cell individuality and genome heterogeneity, it becomes important to evaluate population-wide measurements carefully. An overview of various approaches in microbial ecology is given, and the cell as a central unit for understanding processes on a community level is discussed.

  5. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    Timmers, Ruud A.; Strik, David P.B.T.B.; Hamelers, Bert; Buisman, Cees [Wageningen Univ. (Netherlands). Sub-dept. of Environmental Technology; Rothballer, Michael; Hartmann, Anton [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Microbe-Plant Interactions; Engel, Marion; Schulz, Stephan; Schloter, Michael [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Terrestrial Ecogenetics

    2012-04-15

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors. (orig.)

  6. Recognition of microbial glycolipids by Natural Killer T cells

    Dirk Michael Zajonc

    2015-08-01

    Full Text Available T cells can recognize microbial antigens when presented by dedicated antigen-presenting molecules. While peptides are presented by classical members of the Major Histocompatibility (MHC family (MHC I and II, lipids, glycolipids and lipopeptides can be presented by the non-classical MHC member CD1. The best studied subset of lipid-reactive T cells are Type I Natural killer T (iNKT cells that recognize a variety of different antigens when presented by the non-classical MHCI homolog CD1d. iNKT cells have been shown to be important for the protection against various microbial pathogens, including B. burgdorferi the causative agents of Lyme disease and S. pneumoniae, which causes pneumococcal meningitis and community-acquired pneumonia. Both pathogens carry microbial glycolipids that can trigger the T cell antigen receptor (TCR, leading to iNKT cell activation. iNKT cells have an evolutionary conserved TCR alpha chain, yet retain the ability to recognize structurally diverse glycolipids. They do so using a conserved recognition mode, in which the TCR enforces a conserved binding orientation on CD1d. TCR binding is accompanied by structural changes within the TCR binding site of CD1d, as well as the glycolipid antigen itself. In addition to direct recognition of microbial antigens, iNKT cells can also be activated by a combination of cytokines (IL-12/IL-18 and TCR stimulation. Many microbes carry TLR antigens and microbial infections can lead to TLR activation. The subsequent cytokine response in turn lower the threshold of TCR mediated iNKT cell activation, especially when weak microbial or even self-antigens are presented during the cause of the infection. In summary, iNKT cells can be directly activated through TCR triggering of strong antigens, while cytokines produced by the innate immune response may be necessary for TCR triggering and iNKT cell activation in the presence of weak antigens. Here we will review the molecular basis of iNKT cell

  7. Evaluation of Kefir as a New Anodic Biocatalyst Consortium for Microbial Fuel Cell.

    Silveira, Gustavo; Schneedorf, José Maurício

    2018-02-21

    Kefir, a combined consortium of bacteria and yeast encapsulated by a polymeric matrix of exopolysaccharides, was used as anodic biocatalyst in a two-chamber microbial fuel cell (MFC). Fermentation was followed during 72 h and polarization curves were obtained from linear sweep voltammetry. The effect of methylene blue as charge-transfer mediator in the kefir metabolism was evaluated. UV/Vis spectrophotometry and cyclic voltammetry were applied to evaluate the redox state of the mediator and to characterize the electrochemical activity, whereas current interruption was used for internal resistance determination. Aiming to establish a relationship between the microbial development inside the anodic chamber with the generated power in the MFC, total titratable acidity, pH, viscosity, carbohydrate assimilation, and microbial counting were assayed. The kefir-based MFC demonstrated a maximum power density of 54 mW m -2 after 24 h fermentation, revealing the potential use of kefir as a biocatalyst for microbial fuel cells.

  8. Live Cell Discovery of Microbial Vitamin Transport and Enzyme-Cofactor Interactions

    Anderson, Lindsey N.; Koech, Phillip K.; Plymale, Andrew E.; Landorf, Elizabeth V.; Konopka, Allan; Collart, Frank; Lipton, Mary S.; Romine, Margaret F.; Wright, Aaron T.

    2016-02-02

    The rapid completion of microbial genomes is inducing a conundrum in functional gene discovery. Novel methods are critically needed to shorten the gap between characterizing a microbial genome and experimentally validating bioinformatically-predicted functions. Of particular importance are transport mechanisms, used to shuttle nutrients and metabolites across cell mem-branes, such as B vitamins, which are indispensable to metabolic reactions crucial to the survival of diverse microbes ranging from members of environmental microbial communities to human pathogens. Methods to accurately assign function and specificity for a wide range of experimentally unidentified and/or predicted membrane-embedded transport proteins, and characterization of intra-cellular enzyme-cofactor/nutrient associations are needed to enable a significantly improved understanding of microbial biochemis-try and physiology, how microbes associate with others, and how they sense and respond to environmental perturbations. Chemical probes derived from B vitamins B1, B2, and B7 have allowed us to experimentally address the aforementioned needs by identifying B vitamin transporters and intracellular protein-cofactor associations through live cell labeling of the filamentous anoxygenic pho-toheterotroph, Chloroflexus aurantiacus J-10-fl, known for both B vitamin biosynthesis and environmental salvage. Our probes provide a unique opportunity to directly link cellular activity and protein function back to ecosystem and/or host dynamics by iden-tifying B vitamin transport and disposition mechanisms required for survival.

  9. Treating refinery wastewaters in microbial fuel cells using separator electrode assembly or spaced electrode configurations

    Zhang, Fang; Ahn, Yongtae; Logan, Bruce E.

    2014-01-01

    The effectiveness of refinery wastewater (RW) treatment using air-cathode, microbial fuel cells (MFCs) was examined relative to previous tests based on completely anaerobic microbial electrolysis cells (MECs). MFCs were configured with separator

  10. Metatranscriptomic analysis of diverse microbial communities reveals core metabolic pathways and microbiome-specific functionality.

    Jiang, Yue; Xiong, Xuejian; Danska, Jayne; Parkinson, John

    2016-01-12

    Metatranscriptomics is emerging as a powerful technology for the functional characterization of complex microbial communities (microbiomes). Use of unbiased RNA-sequencing can reveal both the taxonomic composition and active biochemical functions of a complex microbial community. However, the lack of established reference genomes, computational tools and pipelines make analysis and interpretation of these datasets challenging. Systematic studies that compare data across microbiomes are needed to demonstrate the ability of such pipelines to deliver biologically meaningful insights on microbiome function. Here, we apply a standardized analytical pipeline to perform a comparative analysis of metatranscriptomic data from diverse microbial communities derived from mouse large intestine, cow rumen, kimchi culture, deep-sea thermal vent and permafrost. Sequence similarity searches allowed annotation of 19 to 76% of putative messenger RNA (mRNA) reads, with the highest frequency in the kimchi dataset due to its relatively low complexity and availability of closely related reference genomes. Metatranscriptomic datasets exhibited distinct taxonomic and functional signatures. From a metabolic perspective, we identified a common core of enzymes involved in amino acid, energy and nucleotide metabolism and also identified microbiome-specific pathways such as phosphonate metabolism (deep sea) and glycan degradation pathways (cow rumen). Integrating taxonomic and functional annotations within a novel visualization framework revealed the contribution of different taxa to metabolic pathways, allowing the identification of taxa that contribute unique functions. The application of a single, standard pipeline confirms that the rich taxonomic and functional diversity observed across microbiomes is not simply an artefact of different analysis pipelines but instead reflects distinct environmental influences. At the same time, our findings show how microbiome complexity and availability of

  11. Does canine inflammatory bowel disease influence gut microbial profile and host metabolism?

    Xu, Jia; Verbrugghe, Adronie; Lourenço, Marta; Janssens, Geert P J; Liu, Daisy J X; Van de Wiele, Tom; Eeckhaut, Venessa; Van Immerseel, Filip; Van de Maele, Isabel; Niu, Yufeng; Bosch, Guido; Junius, Greet; Wuyts, Brigitte; Hesta, Myriam

    2016-06-16

    Inflammatory bowel disease (IBD) refers to a diverse group of chronic gastrointestinal diseases, and gut microbial dysbiosis has been proposed as a modulating factor in its pathogenesis. Several studies have investigated the gut microbial ecology of dogs with IBD but it is yet unclear if this microbial profile can alter the nutrient metabolism of the host. The aim of the present study was to characterize the faecal bacterial profile and functionality as well as to determine host metabolic changes in IBD dogs. Twenty-three dogs diagnosed with IBD and ten healthy control dogs were included. Dogs with IBD were given a clinical score using the canine chronic enteropathy clinical activity index (CCECAI). Faecal short-chain fatty acids (SCFA) and ammonia concentrations were measured and quantitative PCR was performed. The concentration of plasma amino acids, acylcarnitines, serum folate, cobalamin, and indoxyl sulfate was determined. No significant differences in the abundance of a selection of bacterial groups and fermentation metabolites were observed between the IBD and control groups. However, significant negative correlations were found between CCECAI and the faecal proportion of Lactobacillus as well as between CCECAI and total SCFA concentration. Serum folate and plasma citrulline were decreased and plasma valine was increased in IBD compared to control dogs. Increased plasma free carnitine and total acylcarnitines were observed in IBD compared with control dogs, whereas short-chain acylcarnitines (butyrylcarnitine + isobutyrylcarnitine and, methylmalonylcarnitine) to free carnitine ratios decreased. Dogs with IBD had a higher 3-hydroxyisovalerylcarnitine + isovalerylcarnitine to leucine ratio compared to control dogs. Canine IBD induced a wide range of changes in metabolic profile, especially for the plasma concentrations of short-chain acylcarnitines and amino acids, which could have evolved from tissue damage and alteration in host metabolism. In

  12. Impact of metabolism and growth phase on the hydrogen isotopic composition of microbial fatty acids

    Heinzelmann, Sandra M.; Villanueva, Laura; Sinke-Schoen, Danielle; Sinninghe Damsté, Jaap S.; Schouten, Stefan; van der Meer, Marcel T. J.

    2015-01-01

    Microorganisms are involved in all elemental cycles and therefore it is important to study their metabolism in the natural environment. A recent technique to investigate this is the hydrogen isotopic composition of microbial fatty acids, i.e., heterotrophic microorganisms produce fatty acids enriched in deuterium (D) while photoautotrophic and chemoautotrophic microorganisms produce fatty acids depleted in D compared to the water in the culture medium (growth water). However, the impact of factors other than metabolism have not been investigated. Here, we evaluate the impact of growth phase compared to metabolism on the hydrogen isotopic composition of fatty acids of different environmentally relevant microorganisms with heterotrophic, photoautotrophic and chemoautotrophic metabolisms. Fatty acids produced by heterotrophs are enriched in D compared to growth water with εlipid/water between 82 and 359‰ when grown on glucose or acetate, respectively. Photoautotrophs (εlipid/water between −149 and −264‰) and chemoautotrophs (εlipid/water between −217 and −275‰) produce fatty acids depleted in D. Fatty acids become, in general, enriched by between 4 and 46‰ with growth phase which is minor compared to the influence of metabolisms. Therefore, the D/H ratio of fatty acids is a promising tool to investigate community metabolisms in nature. PMID:26005437

  13. Compost in plant microbial fuel cell for bioelectricity generation

    Moqsud, M.A.; Yoshitake, J.; Bushra, Q.S.; Hyodo, M.; Omine, K.; Strik, D.P.B.T.B.

    2015-01-01

    Recycling of organic waste is an important topic in developing countries as well as developed countries. Compost from organic waste has been used for soil conditioner. In this study, an experiment has been carried out to produce green energy (bioelectricity) by using paddy plant microbial fuel cells

  14. Optimized microbial cells for production of melatonin and other compounds

    2017-01-01

    Described herein are recombinant microbial host cells comprising biosynthetic pathways and their use in producing oxidation products and downstream products, e.g., melatonin and related compounds, as well as enzyme variants, nucleic acids, vectors and methods useful for preparing and using...

  15. Bioelectricity from students' hostel waste water using microbial fuel cell

    Microbial fuel was constructed using two liter plastic transparent chambers representing the cathode and anode poles. The electrodes used were carbon and copper which were utilized in producing a carboncarbon and copper-copper fuel cells respectively. A 1% sodium chloride and 2% agar proton exchange membrane ...

  16. Submersible microbial fuel cell for electricity production from sewage sludge

    Zhang, Yifeng; Olias, Lola Gonzalez; Kongjan, Prawit

    2010-01-01

    A submersible microbial fuel cell (SMFC) was utilized to treatment of sewage sludge and simultaneous generate electricity. Stable power generation (145±5 mW/m2) was produced continuously from raw sewage sludge for 5.5 days. The corresponding total chemical oxygen demand (TCOD) removal efficiency...... of an effective system to treatment of sewage sludge and simultaneous recover energy....

  17. [Effects of nitrogen application rate on faba bean fusarium wilt and rhizospheric microbial metabolic functional diversity].

    Dong, Yan; Yang, Zhi-xian; Dong, Kun; Tang, Li; Zheng, Yi; Hu, Guo-bin

    2013-04-01

    A field plot experiment was conducted to study the effects of different nitrogen (N) application rates on the microbial functional diversity in faba bean rhizosphere and the relationships between the microbial functional diversity and the occurrence of faba bean fusarium wilt. Four nitrogen application rates were installed, i. e. , N0(0 kg hm-2 , N1 (56. 25 kg hm-2) , N2(112. 5 kg hm-2), and N3 (168.75 kg hm-2), and Biolog microbial analysis system was applied to study the damage of faba bean fusarium wilt and the rhizospheric microbial metabolic functional diversity. Applying N (N1 N2, and N3) decreased the disease index of faba bean fusarium wilt and the quantity of Fusarium oxysporum significantly, and increased the quantities of bacteria and actinomyces and the ratios of bacteria/fungi and actinomyces/fungi significantly, with the peak values of bacteria and actinomyces, bacteria/fungi, and actinomyces/fungi, and the lowest disease index and F. oxysporum density in N2. As compared with N0, applying N increased the AWCD value significantly, but the effects of different N application rates on the ability of rhizospheric microbes in utilizing six types of carbon sources had definite differences. Under the application of N, the utilization rates of carbohydrates, carboxylic acids, and amino acids by the rhizospheric microbes were higher. Principal component analysis demonstrated that applying N changed the rhizospheric microbial community composition obviously, and the carbohydrates, carboxylic acids, and amino acids were the sensitive carbon sources differentiating the changes of the microbial community induced by N application. Applying N inhibited the utilization of carbohydrates and carboxylic acids but improved the utilization of amino acids and phenolic acids by the rhizospheric microbes, which could be one of the main reasons of applying N being able to reduce the harm of faba bean fusarium wilt. It was suggested that rationally applying N could increase the

  18. Carbon isotopic patterns of amino acids associated with various microbial metabolic pathways and physiological conditions

    Wang, P. L.; Hsiao, K. T.; Lin, L. H.

    2017-12-01

    Amino acids represent one of the most important categories of biomolecule. Their abundance and isotopic patterns have been broadly used to address issues related to biochemical processes and elemental cycling in natural environments. Previous studies have shown that various carbon assimilative pathways of microorganisms (e.g. autotrophy, heterotrophy and acetotrophy) could be distinguished by carbon isotopic patterns of amino acids. However, the taxonomic and catabolic coverage are limited in previous examination. This study aims to uncover the carbon isotopic patterns of amino acids for microorganisms remaining uncharacterized but bearing biogeochemical and ecological significance in anoxic environments. To fulfill the purpose, two anaerobic strains were isolated from riverine wetland and mud volcano in Taiwan. One strain is a sulfate reducing bacterium (related to Desulfovibrio marrakechensis), which is capable of utilizing either H2 or lactate, and the other is a methanogen (related to Methanolobus profundi), which grows solely with methyl-group compounds. Carbon isotope analyses of amino acids were performed on cells grown in exponential and stationary phase. The isotopic patterns were similar for all examined cultures, showing successive 13C depletion along synthetic pathways. No significant difference was observed for the methanogen and lactate-utilizing sulfate reducer harvested in exponential and stationary phases. In contrast, the H2-utilizing sulfate reducer harvested in stationary phase depleted and enriched 13C in aspartic acid and glycine, respectively when compared with that harvested in exponential phase. Such variations might infer the change of carbon flux during synthesis of these two amino acids in the reverse TCA cycle. In addition, the discriminant function analysis for all available data from culture studies further attests the capability of using carbon isotope patterns of amino acids in identifying microbial metabolisms.

  19. Structural and metabolic responses of microbial community to sewage-borne chlorpyrifos in constructed wetlands.

    Zhang, Dan; Wang, Chuan; Zhang, Liping; Xu, Dong; Liu, Biyun; Zhou, Qiaohong; Wu, Zhenbin

    2016-06-01

    Long-term use of chlorpyrifos poses a potential threat to the environment that cannot be ignored, yet little is known about the succession of substrate microbial communities in constructed wetlands (CWs) under chlorpyrifos stress. Six pilot-scale CW systems receiving artificial wastewater containing 1mg/L chlorpyrifos were established to investigate the effects of chlorpyrifos and wetland vegetation on the microbial metabolism pattern of carbon sources and community structure, using BIOLOG and denaturing gradient gel electrophoresis (DGGE) approaches. Based on our samples, BIOLOG showed that Shannon diversity (H') and richness (S) values distinctly increased after 30days when chlorpyrifos was added. At the same time, differences between the vegetated and the non-vegetated systems disappeared. DGGE profiles indicated that H' and S had no significant differences among four different treatments. The effect of chlorpyrifos on the microbial community was mainly reflected at the physiological level. Principal component analysis (PCA) of both BIOLOG and DGGE showed that added chlorpyrifos made a difference on test results. Meanwhile, there was no difference between the vegetation and no-vegetation treatments after addition of chlorpyrifos at the physiological level. Moreover, the vegetation had no significant effect on the microbial community at the genetic level. Comparisons were made between bacteria in this experiment and other known chlorpyrifos-degrading bacteria. The potential chlorpyrifos-degrading ability of bacteria in situ may be considerable. Copyright © 2016. Published by Elsevier B.V.

  20. Quantitative Raman Spectroscopy to monitor microbial metabolism in situ under pressure

    Picard, A.; Daniel, I.; Oger, P.

    2006-12-01

    Although high hydrostatic pressure (HHP) biotopes are ubiquitous on Earth, little is known about the metabolism of piezophile organisms. Cell culture under HHP can be technically challenging, and equipment- dependent. In addition, the depressurization step required for analysis can lead to erroneous data. Therefore, to understand how piezophile organisms react to pressure, it is crucial to be able to monitor their activity in situ under HHP. We developed the use of Quantitative Raman Spectroscopy (QRS, 1) to monitor in situ the metabolism of organic molecules. This technique is based on the specific spectral signature of an analyte from which its concentration can be deduced. An application of this technique to the monitoring of alcoholic fermentation by the piezotolerant micro-eucaryote Saccharomyces cerevisiae is presented. Ethanol fermentation from glucose was monitored during 24h from ambient P up to 100 MPa in the low- pressure Diamond Anvil Cell (lpDAC, 2). The experimental compression chamber consisted in a 300 μm-thick Ni gasket in which a 500 μm-diameter hole was drilled. Early-stationnary yeast cells were inoculated into fresh low-fluorescence medium containing 0.15 M of glucose. Ethanol concentration was determined in situ by QRS using the symmetric C-C stretching mode of ethanol at 878 cm-1 normalizing the data to the intensity of the sulfate S-O stretching mode at 980 cm-1. In our setup, the detection limit of ethanol is lower than 0.05 mM with a precision below 1%. At ambient P, ethanol production in the lpDAC and in control experiments proceeds with the same kinetics. Thus, yeast is not affected by its confinement. This is further confirmed by its ability to bud with a generation time similar to control experiments performed in glass tubes at ambient pressure inside the lpDAC. Ethanol production by yeast occurs to at least 65 MPa (3). At 10 MPa, fermentation proceeds 3 times faster than at ambient P. Fermentation rates decrease linearly from 20 to

  1. Investigations into the metabolic diversity of microorganisms as part of microbial diversity

    Leadbetter, Jared [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-07-25

    DOE funds supported a key portion of the MBL Microbial Diversity (Woods Hole) program across 6 complete summers. The initial 4 years of the funded period were overseen by two co-Directors, Daniel Buckley (Cornell) and Steve Zinder (Cornell), who then completed their term. The final 2 summers were overseen by 2 new co-Directors, Jared R. Leadbetter (Caltech) and Dianne Newman (Caltech). The 6 funded summer iterations of the course included the incorporation of new themes such as single cell approaches applied to natural microbial communities (cell separation and sorting, genome amplification from single cells, and the use of Nano-SIMS to examine assimilation of carbon and nitrogen from isotopically labeled substrates into single cells), genetics and genomics on bacteria freshly isolated during the course of the programs, quantitative systems biology, and modern quantitative light microscopy.

  2. Copper removal and microbial community analysis in single-chamber microbial fuel cell.

    Wu, Yining; Zhao, Xin; Jin, Min; Li, Yan; Li, Shuai; Kong, Fanying; Nan, Jun; Wang, Aijie

    2018-04-01

    In this study, copper removal and electricity generation were investigated in a single-chamber microbial fuel cell (MFC). Result showed that copper was efficiently removed in the membrane-less MFC with removal efficiency of 98.3% at the tolerable Cu 2+ concentration of 12.5 mg L -1 , the corresponding open circuit voltage and maximum power density were 0.78 V and 10.2 W m -3 , respectively. The mechanism analysis demonstrated that microbial electrochemical reduction contributed to the copper removal with the products of Cu and Cu 2 O deposited at biocathode. Moreover, the microbial community analysis indicated that microbial communities changed with different copper concentrations. The dominant phyla were Proteobacteria and Bacteroidetes which could play key roles in electricity generation, while Actinobacteria and Acidobacteria were also observed which were responsible for Cu-resistant and copper removal. It will be of important guiding significance for the recovery of copper from low concentration wastewater through single-chamber MFC with simultaneous energy recovery. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Elimination of pyraclostrobin by simultaneous microbial degradation coupled with the Fenton process in microbial fuel cells and the microbial community.

    Zhao, Huanhuan; Kong, Chui-Hua

    2018-06-01

    The elimination of pyraclostrobin by simultaneous microbial degradation and Fenton oxidation was achieved in a microbial fuel cell (MFC) system. After 12 h of incubation, the removal rate of pyraclostrobin was 1.4 mg/L/h at the anode and 1.7 mg/L/h at the cathode. The pyraclostrobin concentration was less than the detection limit (0.1 mg/L) after 72 h at the anode and 24 h at the cathode. The air flow rate, temperature, and pH of the catholyte had significant effects on the generation of H 2 O 2 . The maximum production of H 2 O 2 was 1.2 mg/L after reaction for 20 h during the Fenton process. Microbial community analysis indicated that functional bacteria in the genera Chryseobacterium, Stenotrophomonas, Arcobacter, and Comamonas were predominant in the anodic biofilm. In conclusion, the MFC-Fenton system provides an effective approach for treating environmental contaminants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Hydrogen production profiles using furans in microbial electrolysis cells.

    Catal, Tunc; Gover, Tansu; Yaman, Bugra; Droguetti, Jessica; Yilancioglu, Kaan

    2017-06-01

    Microbial electrochemical cells including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are novel biotechnological tools that can convert organic substances in wastewater or biomass into electricity or hydrogen. Electroactive microbial biofilms used in this technology have ability to transfer electrons from organic compounds to anodes. Evaluation of biofilm formation on anode is crucial for enhancing our understanding of hydrogen generation in terms of substrate utilization by microorganisms. In this study, furfural and hydroxymethylfurfural (HMF) were analyzed for hydrogen generation using single chamber membrane-free MECs (17 mL), and anode biofilms were also examined. MECs were inoculated with mixed bacterial culture enriched using chloroethane sulphonate. Hydrogen was succesfully produced in the presence of HMF, but not furfural. MECs generated similar current densities (5.9 and 6 mA/cm 2 furfural and HMF, respectively). Biofilm samples obtained on the 24th and 40th day of cultivation using aromatic compounds were evaluated by using epi-fluorescent microscope. Our results show a correlation between biofilm density and hydrogen generation in single chamber MECs.

  5. Soil Metabolome and Metabolic Fate: Microbial Insights into Freshwater Tidal Wetland Redox Biogeochemistry

    Roy Chowdhury, T.; Bramer, L.; Hoyt, D. W.; Kim, Y. M.; Metz, T. O.; McCue, L. A.; Jansson, J.; Bailey, V. L.

    2017-12-01

    Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands will experience the immediate consequence of climate change as shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the structure and function of the soil microbial populations that in turn will alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of shifting hydrology on the soil microbiome and the role of antecedent moisture condition on redox active microbial processes in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. Our objectives were to characterize changes in the soil microbial community composition in response to soil moisture legacy effects, and to elucidate relationships between community response, geochemical signatures and metabolite profiles in this soil. The 16S rRNA gene sequencing showed significant decreases in bacterial abundance capable of anaerobic metabolism in response to drying, but quickly recovered to the antecedent moisture condition, as observed by redox processes. Metabolomics and biogeochemical process rates generated evidence for moisture-driven redox conditions as principal controls on the community and metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of these pools in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction in compared to methanogenesis. Our results show that anoxic conditions impact microbial communities in both permanently and temporarily saturated conditions and that rapid change in hydrology can increase substrate availability for both aerobic and anaerobic decomposition processes, including methanogenesis.

  6. Recent advances in engineering propionyl-CoA metabolism for microbial production of value-added chemicals and biofuels.

    Srirangan, Kajan; Bruder, Mark; Akawi, Lamees; Miscevic, Dragan; Kilpatrick, Shane; Moo-Young, Murray; Chou, C Perry

    2017-09-01

    Diminishing fossil fuel reserves and mounting environmental concerns associated with petrochemical manufacturing practices have generated significant interests in developing whole-cell biocatalytic systems for the production of value-added chemicals and biofuels. Although acetyl-CoA is a common natural biogenic precursor for the biosynthesis of numerous metabolites, propionyl-CoA is unpopular and non-native to most organisms. Nevertheless, with its C3-acyl moiety as a discrete building block, propionyl-CoA can serve as another key biogenic precursor to several biological products of industrial importance. As a result, engineering propionyl-CoA metabolism, particularly in genetically tractable hosts with the use of inexpensive feedstocks, has paved an avenue for novel biomanufacturing. Herein, we present a systematic review on manipulation of propionyl-CoA metabolism as well as relevant genetic and metabolic engineering strategies for microbial production of value-added chemicals and biofuels, including odd-chain alcohols and organic acids, bio(co)polymers and polyketides. [Formula: see text].

  7. A review on the bioenergetics of anaerobic microbial metabolism close to the thermodynamic limits and its implications for digestion applications.

    Leng, Ling; Yang, Peixian; Singh, Shubham; Zhuang, Huichuan; Xu, Linji; Chen, Wen-Hsing; Dolfing, Jan; Li, Dong; Zhang, Yan; Zeng, Huiping; Chu, Wei; Lee, Po-Heng

    2018-01-01

    The exploration of the energetics of anaerobic digestion systems can reveal how microorganisms cooperate efficiently for cell growth and methane production, especially under low-substrate conditions. The establishment of a thermodynamically interdependent partnership, called anaerobic syntrophy, allows unfavorable reactions to proceed. Interspecies electron transfer and the concentrations of electron carriers are crucial for maintaining this mutualistic activity. This critical review summarizes the functional microorganisms and syntroph partners, particularly in the metabolic pathways and energy conservation of syntrophs. The kinetics and thermodynamics of propionate degradation to methane, reversibility of the acetate oxidation process, and estimation of microbial growth are summarized. The various routes of interspecies electron transfer, reverse electron transfer, and Poly-β-hydroxyalkanoate formation in the syntrophic community are also reviewed. Finally, promising and critical directions of future research are proposed. Fundamental insight in the activities and interactions involved in AD systems could serve as a guidance for engineered systems optimization and upgrade. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea hydrothermal systems.

    Zhang, Yao; Zhao, Zihao; Chen, Chen-Tung Arthur; Tang, Kai; Su, Jianqiang; Jiao, Nianzhi

    2012-01-01

    To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea hydrothermal vent systems off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white hydrothermal vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different hydrothermal plumes. The bacterial and archaeal communities from the white hydrothermal plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow hydrothermal plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4)) concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4) was less tied to microbial processes in this shallow-sea hydrothermal system. We speculated that mixing between hydrothermal fluids and the sea or meteoric water leads to distinctly different CH(4) concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow hydrothermal systems off the coast of NE Taiwan.

  9. Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea hydrothermal systems.

    Yao Zhang

    Full Text Available To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea hydrothermal vent systems off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white hydrothermal vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different hydrothermal plumes. The bacterial and archaeal communities from the white hydrothermal plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow hydrothermal plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4 concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4 was less tied to microbial processes in this shallow-sea hydrothermal system. We speculated that mixing between hydrothermal fluids and the sea or meteoric water leads to distinctly different CH(4 concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow hydrothermal systems off the coast of NE Taiwan.

  10. Nitrogen metabolism and microbial production of dairy cows fed sugarcane and nitrogen compounds

    Gonçalves,Geógenes da Silva; Pedreira,Marcio dos Santos; Pereira,Mara Lúcia Albuquerque; Santos,Dimas Oliveira; Souza,Dicastro Dias de; Porto Junior,Antonio Ferraz

    2014-01-01

    The aim of this study was to evaluate the effect of dairy cow diets containing two different sources of urea on nitrogen metabolism and microbial synthesis. Eight crossbred cows were confined and distributed in two 4x4 Latin: FS - soybean meal (control), conventional urea (UC) 100%; ULL 44 UC = 56% / 44% ULL, ULL 88 UC = 12% / 88% ULL. Diets were offered to animals during 21 days with 14 days of adaptation. The N intake, retained nitrogen balance, nitrogen excretion in milk, urine, feces and ...

  11. Metabolic commensalism and competition in a two-species microbial consortium

    Christensen, Bjarke Bak; Haagensen, Janus Anders Juul; Heydorn, Arne

    2002-01-01

    We analyzed metabolic interactions and the importance of specific structural relationships in a benzyl alcohol-degrading microbial consortium comprising two species, Pseudomonas putida strain R1 and Acinetobacter strain C6, both of which are able to utilize benzyl alcohol as their sole carbon...... alcohol, which apparently gives Acinetobacter strain C6 a growth advantage, probably because it converts benzyl alcohol to benzoate with a higher yield per time unit than P. putida R1. In biofilms, however, the organisms establish structured, surface-attached consortia, in which heterogeneous ecological...... niches develop, and under these conditions competition for the primary carbon source is not the only determinant of biomass and population structure....

  12. The JBEI quantitative metabolic modeling library (jQMM): a python library for modeling microbial metabolism

    Birkel, Garrett W.; Ghosh, Amit; Kumar, Vinay S.

    2017-01-01

    analysis, new methods for the effective use of the ever more readily available and abundant -omics data (i.e. transcriptomics, proteomics and metabolomics) are urgently needed.Results: The jQMM library presented here provides an open-source, Python-based framework for modeling internal metabolic fluxes......, it introduces the capability to use C-13 labeling experimental data to constrain comprehensive genome-scale models through a technique called two-scale C-13 Metabolic Flux Analysis (2S-C-13 MFA). In addition, the library includes a demonstration of a method that uses proteomics data to produce actionable...... insights to increase biofuel production. Finally, the use of the jQMM library is illustrated through the addition of several Jupyter notebook demonstration files that enhance reproducibility and provide the capability to be adapted to the user's specific needs.Conclusions: jQMM will facilitate the design...

  13. Bioconversion of cellulose into electrical energy in microbial fuel cells

    Rismani-Yazdi, Hamid

    In microbial fuel cells (MFCs), bacteria generate electricity by mediating the oxidation of organic compounds and transferring the resulting electrons to an anode electrode. The first objective of this study was to test the possibility of generating electricity with rumen microorganisms as biocatalysts and cellulose as the electron donor in two-compartment MFCs. Maximum power density reached 55 mW/m2 (1.5 mA, 313 mV) with cellulose as the electron donor. Cellulose hydrolysis and electrode reduction were shown to support the production of current. The electrical current was sustained for over two months with periodic cellulose addition. Clarified rumen fluid and a soluble carbohydrate mixture, serving as the electron donors, could also sustain power output. The second objective was to analyze the composition of the bacterial communities enriched in the cellulose-fed MFCs. Denaturing gradient gel electrophoresis of PCR amplified 16S rRNA genes revealed that the microbial communities differed when different substrates were used in the MFCs. The anode-attached and the suspended consortia were shown to be different within the same MFC. Cloning and analysis of 16S rRNA gene sequences indicated that the most predominant bacteria in the anode-attached consortia were related to Clostridium spp., while Comamonas spp. was abundant in the suspended consortia. The external resistance affects the characteristic outputs of MFCs by controlling the flow of electrons from the anode to the cathode. The third objective of this study was to determine the effect of various external resistances on power output and coulombic efficiency of cellulose-fed MFCs. Four external resistances (20, 249, 480, and 1000 ohms) were tested with a systematic approach of operating parallel MFCs independently at constant circuit loads for three months. A maximum power density of 66 mWm-2 was achieved by MFCs with 20 ohms circuit load, while MFCs with 249, 480 and1000 ohms external resistances produced 57

  14. Reconstructing each cell's genome within complex microbial communities-dream or reality?

    Clingenpeel, Scott; Clum, Alicia; Schwientek, Patrick; Rinke, Christian; Woyke, Tanja

    2014-01-01

    As the vast majority of microorganisms have yet to be cultivated in a laboratory setting, access to their genetic makeup has largely been limited to cultivation-independent methods. These methods, namely metagenomics and more recently single-cell genomics, have become cornerstones for microbial ecology and environmental microbiology. One ultimate goal is the recovery of genome sequences from each cell within an environment to move toward a better understanding of community metabolic potential and to provide substrate for experimental work. As single-cell sequencing has the ability to decipher all sequence information contained in an individual cell, this method holds great promise in tackling such challenge. Methodological limitations and inherent biases however do exist, which will be discussed here based on environmental and benchmark data, to assess how far we are from reaching this goal.

  15. Nanomodification of the electrodes in microbial fuel cell: impact of nanoparticle density on electricity production and microbial community

    Al Atraktchi, Fatima Al-Zahraa; Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    The nano-decoration of electrode with nanoparticles is one effective way to enhance power output of microbial fuel cells (MFCs). However, the amount of nanoparticles used for decoration has not been optimized yet, and how it affects the microbial community is still unknown. In this study, differe...

  16. Electricity generation from the mud by using microbial fuel cell

    Idris Sitinoor Adeib

    2016-01-01

    Full Text Available Microbial fuel cells (MFCs is a bio-electrochemical device that harnesses the power of respiring microbes to convert organic substrates directly into electrical energy. This is achieved when bacteria transfer electrons to an electrode rather than directly to an electron acceptor. Their technical feasibility has recently been proven and there is great enthusiasm in the scientific community that MFCs could provide a source of “green electricity”. Microbial fuel cells work by allowing bacteria to do what they do best, oxidize and reduce organic molecules. Bacterial respiration is basically one big redox reaction in which electrons are being moved around. The objective is to generate electricity throughout the biochemical process using chemical waste basically sludge, via microbial fuel cells. The methodology includes collecting sludge from different locations, set up microbial fuel cells with the aid of salt bridge and observing the results in voltage measurement. The microbial fuel cells consist of two chambers, iron electrodes, copper wire, air pump (to increase the efficiency of electron transfer, water, sludge and salt bridge. After several observations, it is seen that this MFC can achieve up until 202 milivolts (0.202volts with the presence of air pump. It is proven through the experiments that sludge from different locations gives different results in term of the voltage measurement. This is basically because in different locations of sludge contain different type and amount of nutrients to provide the growth of bacteria. Apart from that, salt bridge also play an important role in order to transport the proton from cathode to anode. A longer salt bridge will give a higher voltage compared to a short salt bridge. On the other hand, the limitations that this experiment facing is the voltage that being produced did not last long as the bacteria activity slows down gradually and the voltage produced are not really great in amount. Lastly to

  17. Advances in metabolic engineering in the microbial production of fuels and chemicals from C1 gas.

    Humphreys, Christopher M; Minton, Nigel P

    2018-04-01

    The future sustainable production of chemicals and fuels from non-petrochemical sources, while at the same time reducing greenhouse gas (GHG) emissions, represent two of society's greatest challenges. Microbial chassis able to grow on waste carbon monoxide (CO) and carbon dioxide (CO 2 ) can provide solutions to both. Ranging from the anaerobic acetogens, through the aerobic chemoautotrophs to the photoautotrophic cyanobacteria, they are able to convert C1 gases into a range of chemicals and fuels which may be enhanced and extended through appropriate metabolic engineering. The necessary improvements will be facilitated by the increasingly sophisticated gene tools that are beginning to emerge as part of the Synthetic Biology revolution. These tools, in combination with more accurate metabolic and genome scale models, will enable C1 chassis to deliver their full potential. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Electricity production from microbial fuel cell by using yeast

    Vorasingha, A.; Souvakon, C.; Boonchom, K.

    2006-01-01

    The continuous search for methods to generate electricity from renewable sources such as water, solar energy, wind, nuclear or chemicals was discussed with particular focus on attaining the full power of the microbial fuel cell (MFC). Under ideal environmental conditions, the only byproducts of a biofuel cell would be water and carbon dioxide (CO 2 ). The production of energy from renewables such as biomass is important for sustainable development and reducing global emissions of CO 2 . Hydrogen can also be an important component of an energy infrastructure that reduces CO 2 emissions if the hydrogen is produced from renewable sources and used in fuel cells. Hydrogen gas can be biologically produced at high concentration from the fermentation of high sugar substrates such as glucose and sucrose. Some of the issues of MFC design were addressed, including the use of cheap substrates to derive microbial electricity. In the MFC, yeast donates electrons to a chemical electron mediator, which in turn transfers the electrons to an electrode, producing electricity. Experimental results showed that glucose yielded the highest peak voltage, but a semi-processed sugar and molasses were similar to glucose in the electricity production pattern. It was noted that this technology is only at the research stages, and more research is needed before household microbial fuel cells can be made available for producing power for prolonged periods of time. Future research efforts will focus on increasing the efficiency, finding alternatives to hazardous electron mediators and finding new microbes. 12 refs., 6 figs

  19. METABOLIC MODELLING IN THE DEVELOPMENT OF CELL FACTORIES BY SYNTHETIC BIOLOGY

    Paula Jouhten

    2012-10-01

    Full Text Available Cell factories are commonly microbial organisms utilized for bioconversion of renewable resources to bulk or high value chemicals. Introduction of novel production pathways in chassis strains is the core of the development of cell factories by synthetic biology. Synthetic biology aims to create novel biological functions and systems not found in nature by combining biology with engineering. The workflow of the development of novel cell factories with synthetic biology is ideally linear which will be attainable with the quantitative engineering approach, high-quality predictive models, and libraries of well-characterized parts. Different types of metabolic models, mathematical representations of metabolism and its components, enzymes and metabolites, are useful in particular phases of the synthetic biology workflow. In this minireview, the role of metabolic modelling in synthetic biology will be discussed with a review of current status of compatible methods and models for the in silico design and quantitative evaluation of a cell factory.

  20. Bioelectrochemical metal recovery with microbial fuel cells

    Rodenas Motos, Pau

    2017-01-01

    This thesis aims to explain the metal recovery through the study of their components using Copper as a model compound of the heavy metals. Different electrochemical cells distribution and sizes were used to improve efficiency and current density. Two different electron donors were tested, acetate

  1. Characterization of Microbial Fuel Cells at Microbially and Electrochemically Meaningful Time scales

    Ren, Zhiyong

    2011-03-15

    The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant time scales that are insufficient to account for these variable biocatalyst effects. This study investigated the electrochemical performance and the development of anode biofilm architecture under different external loadings, with duplicate acetate-fed singlechamber MFCs stabilized at each resistance for microbially relevant time scales. Power density curves from these steady-state reactors generally showed comparable profiles despite the fact that anode biofilm architectures and communities varied considerably, showing that steady-state biofilm differences had little influence on electrochemical performance until the steady-state external loading was much larger than the reactor internal resistance. Filamentous bacteria were dominant on the anodes under high external resistances (1000 and 5000 Ω), while more diverse rod-shaped cells formed dense biofilms under lower resistances (10, 50, and 265 Ω). Anode charge transfer resistance decreased with decreasing fixed external resistances, but was consistently 2 orders of magnitude higher than the resistance at the cathode. Cell counting showed an inverse exponential correlation between cell numbers and external resistances. This direct link ofMFCanode biofilm evolution with external resistance and electricity production offers several operational strategies for system optimization. © 2011 American Chemical Society.

  2. Computational design of auxotrophy-dependent microbial biosensors for combinatorial metabolic engineering experiments.

    Tepper, Naama; Shlomi, Tomer

    2011-01-21

    Combinatorial approaches in metabolic engineering work by generating genetic diversity in a microbial population followed by screening for strains with improved phenotypes. One of the most common goals in this field is the generation of a high rate chemical producing strain. A major hurdle with this approach is that many chemicals do not have easy to recognize attributes, making their screening expensive and time consuming. To address this problem, it was previously suggested to use microbial biosensors to facilitate the detection and quantification of chemicals of interest. Here, we present novel computational methods to: (i) rationally design microbial biosensors for chemicals of interest based on substrate auxotrophy that would enable their high-throughput screening; (ii) predict engineering strategies for coupling the synthesis of a chemical of interest with the production of a proxy metabolite for which high-throughput screening is possible via a designed bio-sensor. The biosensor design method is validated based on known genetic modifications in an array of E. coli strains auxotrophic to various amino-acids. Predicted chemical production rates achievable via the biosensor-based approach are shown to potentially improve upon those predicted by current rational strain design approaches. (A Matlab implementation of the biosensor design method is available via http://www.cs.technion.ac.il/~tomersh/tools).

  3. Hematopoietic stem cell fate through metabolic control.

    Ito, Kyoko; Ito, Keisuke

    2018-05-25

    Hematopoietic stem cells (HSCs) maintain a quiescent state in the bone marrow to preserve their self-renewal capacity, but also undergo cell divisions as required. Organelles such as the mitochondria sustain cumulative damage during these cell divisions, and this damage may eventually compromise the cells' self-renewal capacity. HSC divisions result in either self-renewal or differentiation, with the balance between the two directly impacting hematopoietic homeostasis; but the heterogeneity of available HSC-enriched fractions, together with the technical challenges of observing HSC behavior, has long hindered the analysis of individual HSCs, and prevented the elucidation of this process. However, recent advances in genetic models, metabolomics analyses and single-cell approaches have revealed the contributions made to HSC self-renewal by metabolic cues, mitochondrial biogenesis, and autophagy/mitophagy, which have highlighted mitochondrial quality as a key control factor in the equilibrium of HSCs. A deeper understanding of precisely how specific modes of metabolism control HSC fate at the single cell level is therefore not only of great biological interest, but will have clear clinical implications for the development of therapies for hematological disease. Copyright © 2018. Published by Elsevier Inc.

  4. Microbial metaproteomics for characterizing the range of metabolic functions and activities of human gut microbiota.

    Xiong, Weili; Abraham, Paul E; Li, Zhou; Pan, Chongle; Hettich, Robert L

    2015-10-01

    The human gastrointestinal tract is a complex, dynamic ecosystem that consists of a carefully tuned balance of human host and microbiota membership. The microbiome is not merely a collection of opportunistic parasites, but rather provides important functions to the host that are absolutely critical to many aspects of health, including nutrient transformation and absorption, drug metabolism, pathogen defense, and immune system development. Microbial metaproteomics provides the ability to characterize the human gut microbiota functions and metabolic activities at a remarkably deep level, revealing information about microbiome development and stability as well as their interactions with their human host. Generally, microbial and human proteins can be extracted and then measured by high performance MS-based proteomics technology. Here, we review the field of human gut microbiome metaproteomics, with a focus on the experimental and informatics considerations involved in characterizing systems ranging from low-complexity model gut microbiota in gnotobiotic mice, to the emerging gut microbiome in the GI tract of newborn human infants, and finally to an established gut microbiota in human adults. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Temporal Microbial Community Dynamics in Microbial Electrolysis Cells – Influence of Acetate and Propionate Concentration

    Rao, Hari Ananda

    2017-07-20

    Microbial electrolysis cells (MECs) are widely considered as a next generation wastewater treatment system. However, fundamental insight on the temporal dynamics of microbial communities associated with MEC performance under different organic types with varied loading concentrations is still unknown, nevertheless this knowledge is essential for optimizing this technology for real-scale applications. Here, the temporal dynamics of anodic microbial communities associated with MEC performance was examined at low (0.5 g COD/L) and high (4 g COD/L) concentrations of acetate or propionate, which are important intermediates of fermentation of municipal wastewaters and sludge. The results showed that acetate-fed reactors exhibited higher performance in terms of maximum current density (I: 4.25 ± 0.23 A/m), coulombic efficiency (CE: 95 ± 8%), and substrate degradation rate (98.8 ± 1.2%) than propionate-fed reactors (I: 2.7 ± 0.28 A/m; CE: 68 ± 9.5%; substrate degradation rate: 84 ± 13%) irrespective of the concentrations tested. Despite of the repeated sampling of the anodic biofilm over time, the high-concentration reactors demonstrated lower and stable performance in terms of current density (I: 1.1 ± 0.14 to 4.2 ± 0.21 A/m), coulombic efficiency (CE: 44 ± 4.1 to 103 ± 7.2%) and substrate degradation rate (64.9 ± 6.3 to 99.7 ± 0.5%), while the low-concentration reactors produced higher and dynamic performance (I: 1.1 ± 0.12 to 4.6 ± 0.1 A/m; CE: 52 ± 2.5 to 105 ± 2.7%; substrate degradation rate: 87.2 ± 0.2 to 99.9 ± 0.06%) with the different substrates tested. Correlating reactor\\'s performance with temporal dynamics of microbial communities showed that relatively similar anodic microbial community composition but with varying relative abundances was observed in all the reactors despite differences in the substrate and concentrations tested. Particularly, Geobacter was the predominant bacteria on the anode biofilm of all MECs over time suggesting its

  6. Enzyme Amplified Detection of Microbial Cell Wall Components

    Wainwright, Norman R.

    2004-01-01

    This proposal is MBL's portion of NASA's Johnson Space Center's Astrobiology Center led by Principal Investigator, Dr. David McKay, entitled: 'Institute for the Study of Biomarkers in Astromaterials.' Dr. Norman Wainwright is the principal investigator at MBL and is responsible for developing methods to detect trace quantities of microbial cell wall chemicals using the enzyme amplification system of Limulus polyphemus and other related methods.

  7. Sediment microbial fuel cells for wastewater treatment: challenges and opportunities

    Xu, Bojun; Ge, Zheng; He, Zhen

    2015-01-01

    Sediment microbial fuel cells (SMFCs) have been intensively investigated for the harvest of energy from natural sediment, but studies of their application for wastewater treatment mainly occurred in the past 2-3 years. SMFCs with simple structures can generate electrical energy while decontaminating wastewater. Most SMFCs used for wastewater treatment contain plants to mimic constructed wetlands. Both synthetic and real wastewaters have been used as substrates in SMFCs that achieved satisfact...

  8. Submersible microbial fuel cell for electricity production from sewage sludge

    Zhang, Yifeng; Olias, Lola Gonzalez; Kongjan, Prawit

    2011-01-01

    A submersible microbial fuel cell (SMFC) was utilized to treat sewage sludge and simultaneously generate electricity. Stable power generation (145± 5 mW/m2, 470 Ω) was produced continuously from raw sewage sludge for 5.5 days. The maximum power density reached 190±5 mW/m2. The corresponding total...... system to treat sewage sludge and simultaneously recover energy....

  9. Enhanced microbial reduction of vanadium (V) in groundwater with bioelectricity from microbial fuel cells

    Hao, Liting; Zhang, Baogang; Tian, Caixing; Liu, Ye; Shi, Chunhong; Cheng, Ming; Feng, Chuanping

    2015-08-01

    Bioelectricity generated from the microbial fuel cell (MFC) is applied to the bioelectrical reactor (BER) directly to enhance microbial reduction of vanadium (V) (V(V)) in groundwater. With the maximum power density of 543.4 mW m-2 from the MFC, V(V) removal is accelerated with efficiency of 93.6% during 12 h operation. Higher applied voltage can facilitate this process. V(V) removals decrease with the increase of initial V(V) concentration, while extra addition of chemical oxygen demand (COD) has little effect on performance improvement. Microbial V(V) reduction is enhanced and then suppressed with the increase of conductivity. High-throughput 16S rRNA gene pyrosequencing analysis implies the accumulated Enterobacter and Lactococcus reduce V(V) with products from fermentative microorganisms such as Macellibacteroides. The presentation of electrochemically active bacteria as Enterobacter promotes electron transfers. This study indicates that application of bioelectricity from MFCs is a promising strategy to improve the efficiency of in-situ bioremediation of V(V) polluted groundwater.

  10. Micropillar arrays enabling single microbial cell encapsulation in hydrogels.

    Park, Kyun Joo; Lee, Kyoung G; Seok, Seunghwan; Choi, Bong Gill; Lee, Moon-Keun; Park, Tae Jung; Park, Jung Youn; Kim, Do Hyun; Lee, Seok Jae

    2014-06-07

    Single microbial cell encapsulation in hydrogels is an important task to find valuable biological resources for human welfare. The conventional microfluidic designs are mainly targeted only for highly dispersed spherical bioparticles. Advanced structures should be taken into consideration for handling such aggregated and non-spherical microorganisms. Here, to address the challenge, we propose a new type of cylindrical-shaped micropillar array in a microfluidic device for enhancing the dispersion of cell clusters and the isolation of individual cells into individual micro-hydrogels for potential practical applications. The incorporated micropillars act as a sieve for the breaking of Escherichia coli (E. coli) clusters into single cells in a polymer mixture. Furthermore, the combination of hydrodynamic forces and a flow-focusing technique will improve the probability of encapsulation of a single cell into each hydrogel with a broad range of cell concentrations. This proposed strategy and device would be a useful platform for genetically modified microorganisms for practical applications.

  11. Effects of Pheretima Guillelmi Cultivation Time on Microbial Community Diversity and Characteristics of Carbon Metabolism in Vegetable Soil

    ZHENG Xian-qing

    2015-12-01

    Full Text Available In order to study the effect of different biological tillage time (Pheretima guillelmi on soil microbial community metabolic functions in different soil depths, we set a location test in vegetable field at Chongming Island in Shanghai to analyze the changes of soil microbial community and carbon utilization abilities (Average well- color development, AWCD by using biolog eco-plate method. The three-year results showed that: Bio-tillage significantly improved microbial community activity, and with the increase of tillage years, biological tillage could make the average AWCD 3 to 7 times higher. The Simpson index and Shannon index of the biological tillage treatments were significantly higher than that of the control. The cumulative increase of 0~5 cm soil layer was 49 and 6.28 respectively, and the cumulative increase of 5~20 cm soil layer was 31 and 2.55 respectively. Earthworm bio-tillage significantly increased the soil microbial metabolic ability of 6 kinds of carbon sources, and increased the carbohydrate metabolism activity. In this study, earthworm bio-tillage is an effective way to increase the microbial activity of microbial soil.

  12. Bioelectricity Production from Microalgae-Microbial Fuel Cell Technology (MMFC

    da Costa Carlito

    2018-01-01

    Full Text Available Microbial fuel cell is an ecological innovative technology producing bioelectricity by utilizing microbes activity. Substituent energy is produced by changing the chemical energy to electrical energy through the catalytic reaction of microorganism. The research aims to find out the potency of bioelectricity produced by microalgae microbial fuel cell technology by utilizing the combination of tapioca wastewater and microalgae cultivation. This research is conducted through the ingredients preparation stage – microalgae culture, wastewater characterization, membrane and graphite activation, and the providing of other supporting equipment. The next stage is the MMFC arrangement, while the last one is bioelectricity measurement. The result of optimal bioelectricity production on the comparison of electrode 2 : 2, the power density is 44,33 mW/m2 on day 6, meanwhile, on that of 1 : 1, 20,18 mW/m2 power density on day 1 is obtained. It shows that bioelectricity can be produced from the combination of tapioca wastewater and microalgae culture through the microalgae-microbial fuel cell (MMFC technology.This research is expected to be a reference for the next research particularly the one that observes the utilizing of microalgae as the part of new and renewable energy sources.

  13. Using isotopic tracers to assess the impact of tillage and straw management on the microbial metabolic network in soil

    Van Groenigen, K.; Forristal, D.; Jones, M. B.; Schwartz, E.; Hungate, B. A.; Dijkstra, P.

    2013-12-01

    By decomposing soil organic matter, microbes gain energy and building blocks for biosynthesis and release CO2 to the atmosphere. Therefore, insight into the effect of management practices on microbial metabolic pathways and C use efficiency (CUE; microbial C produced per substrate C utilized) may help to predict long term changes in soil C stocks. We studied the effects of reduced (RT) and conventional tillage (CT) on the microbial central C metabolic network, using soil samples from a 12-year-old field experiment in an Irish winter wheat cropping system. Each year after harvest, straw was removed from half of the RT and CT plots or incorporated into the soil in the other half, resulting in four treatment combinations. We added 1-13C and 2,3-13C pyruvate and 1-13C and U-13C glucose as metabolic tracer isotopomers to composite soil samples taken at two depths (0-15 cm and 15-30 cm) from each treatment and used the rate of position-specific respired 13CO2 to parameterize a metabolic model. Model outcomes were then used to calculate CUE of the microbial community. We found that the composite samples differed in CUE, but the changes were small, with values ranging between 0.757-0.783 across treatments and soil depth. Increases in CUE were associated with a decrease in tricarboxylic acid cycle and reductive pentose phosphate pathway activity and increased consumption of metabolic intermediates for biosynthesis. Our results indicate that RT and straw incorporation promote soil C storage without substantially changing CUE or any of the microbial metabolic pathways. This suggests that at our site, RT and straw incorporation promote soil C storage mostly through direct effects such as increased soil C input and physical protection from decomposition, rather than by feedback responses of the microbial community.

  14. Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

    Kim, Daehee; Chang, In Seop

    2009-10-01

    A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

  15. Performance of microbial fuel cell double chamber using mozzarella cheese whey substrate

    Darmawan, M. D.; Hawa, L. C.; Argo, B. D.

    2018-03-01

    Nowadays the availability of electric energy is decreasing, hence there is a need for innovation of electric energy producer alternative; one of them is microbial fuel cell (MFC). MFC is a bioelectrochemical system generated by bacterial metabolism that utilizes organic substrate. One of the substrates that can be used is whey, a waste generated from cheese production. Therefore, this study aimed to determine the power of potential current and voltage generated from the use of whey cheese as a substrate for bacterial metabolism. In this research, double chamber system was used in microbial fuel cell reactor by using cheese whey as substrate at anode and potassium permanganate as cathode and utilizing membrane nafion 212 as membrane of proton exchange. The variable of experiment was bacteria type. The types of bacteria used in this study were Lactobacillus bulgaricus, Streptococcus thermophillus and Lactobacillus casei. While the operating time used was 100 hours. The highest current produced was 74.6 μA and the highest voltage was 529.3 mV produced by Lactobacillus bulgaricus bacteria. In this study, it was also found that the death phase of the three bacteria was at 70-80 hours.

  16. Pyruvate Kinase Triggers a Metabolic Feedback Loop that Controls Redox Metabolism in Respiring Cells

    Grüning, N.M.; Rinnerthaler, M.; Bluemlein, K.; Mulleder, M.; Wamelink, M.M.C.; Lehrach, H.; Jakobs, C.A.J.M.; Breitenbach, M.; Ralser, M.

    2011-01-01

    In proliferating cells, a transition from aerobic to anaerobic metabolism is known as the Warburg effect, whose reversal inhibits cancer cell proliferation. Studying its regulator pyruvate kinase (PYK) in yeast, we discovered that central metabolism is self-adapting to synchronize redox metabolism

  17. Metabolic features of the cell danger response.

    Naviaux, Robert K

    2014-05-01

    The cell danger response (CDR) is the evolutionarily conserved metabolic response that protects cells and hosts from harm. It is triggered by encounters with chemical, physical, or biological threats that exceed the cellular capacity for homeostasis. The resulting metabolic mismatch between available resources and functional capacity produces a cascade of changes in cellular electron flow, oxygen consumption, redox, membrane fluidity, lipid dynamics, bioenergetics, carbon and sulfur resource allocation, protein folding and aggregation, vitamin availability, metal homeostasis, indole, pterin, 1-carbon and polyamine metabolism, and polymer formation. The first wave of danger signals consists of the release of metabolic intermediates like ATP and ADP, Krebs cycle intermediates, oxygen, and reactive oxygen species (ROS), and is sustained by purinergic signaling. After the danger has been eliminated or neutralized, a choreographed sequence of anti-inflammatory and regenerative pathways is activated to reverse the CDR and to heal. When the CDR persists abnormally, whole body metabolism and the gut microbiome are disturbed, the collective performance of multiple organ systems is impaired, behavior is changed, and chronic disease results. Metabolic memory of past stress encounters is stored in the form of altered mitochondrial and cellular macromolecule content, resulting in an increase in functional reserve capacity through a process known as mitocellular hormesis. The systemic form of the CDR, and its magnified form, the purinergic life-threat response (PLTR), are under direct control by ancient pathways in the brain that are ultimately coordinated by centers in the brainstem. Chemosensory integration of whole body metabolism occurs in the brainstem and is a prerequisite for normal brain, motor, vestibular, sensory, social, and speech development. An understanding of the CDR permits us to reframe old concepts of pathogenesis for a broad array of chronic, developmental

  18. Microbial fuel cells for clogging assessment in constructed wetlands

    Corbella, Clara; García, Joan; Puigagut, Jaume

    2016-01-01

    Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20 kg TS·m"− "3 CW·year"− "1 at the beginning of the study period up to ca. 250 kg TS·m"− "3 CW·year"− "1 at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2 years (ca. 0.5 kg TS·m"–"3CW) to ca. 5 years (ca. 10 kg TS·m"–"3CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5 years of clogging (ca. 10 kg TS·m"–"3CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. - Highlights: • Microbial fuel cells are used as tool for clogging assessment in constructed wetlands. • Microbial fuel cells were loaded with sludge from constructed wetlands. • Sludge retained within the systems simulated a clogging time ranging from 0.2 to ca. 5 years. • Electrons transferred decreased potentially as function of sludge loading. • Microbial fuel cells have potential for clogging assessment

  19. Microbial fuel cells for clogging assessment in constructed wetlands

    Corbella, Clara; García, Joan; Puigagut, Jaume, E-mail: jaume.puigagut@upc.edu

    2016-11-01

    Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the beginning of the study period up to ca. 250 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2 years (ca. 0.5 kg TS·m{sup –3}CW) to ca. 5 years (ca. 10 kg TS·m{sup –3}CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5 years of clogging (ca. 10 kg TS·m{sup –3}CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. - Highlights: • Microbial fuel cells are used as tool for clogging assessment in constructed wetlands. • Microbial fuel cells were loaded with sludge from constructed wetlands. • Sludge retained within the systems simulated a clogging time ranging from 0.2 to ca. 5 years. • Electrons transferred decreased potentially as function of sludge loading.

  20. Electrically conductive, immobilized bioanodes for microbial fuel cells

    Ganguli, R; Dunn, B

    2012-01-01

    The power densities of microbial fuel cells with yeast cells as the anode catalyst were significantly increased by immobilizing the yeast in electrically conductive alginate electrodes. The peak power densities measured as a function of the electrical conductivity of the immobilized electrodes show that although power increases with rising electrical conductivity, it tends to saturate beyond a certain point. Changing the pH of the anode compartment at that point seems to further increase the power density, suggesting that proton transport limitations and not electrical conductivity will limit the power density from electrically conductive immobilized anodes. (paper)

  1. Assessment of Microbial Fuel Cell Configurations and Power Densities

    Logan, Bruce E.

    2015-07-30

    Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

  2. Microbial fuel cell based on electroactive sulfate-reducing biofilm

    Angelov, Anatoliy; Bratkova, Svetlana; Loukanov, Alexandre

    2013-01-01

    Highlights: ► Regulation and management of electricity generation by variation of residence time. ► Design of microbial fuel cell based on electroactive biofilm on zeolite. ► Engineering solution for removing of the obtained elemental sulfur. - abstract: A two chambered laboratory scale microbial fuel cell (MFC) has been developed, based on natural sulfate-reducing bacterium consortium in electroactive biofilm on zeolite. The MFC utilizes potassium ferricyanide in the cathode chamber as an electron acceptor that derives electrons from the obtained in anode chamber H 2 S. The molecular oxygen is finally used as a terminal electron acceptor at cathode compartment. The generated power density was 0.68 W m −2 with current density of 3.2 A m −2 at 150 Ω electrode resistivity. The hydrogen sulfide itself is produced by microbial dissimilative sulfate reduction process by utilizing various organic substrates. Finally, elemental sulfur was identified as the predominant final oxidation product in the anode chamber. It was removed from MFC through medium circulation and gathering in an external tank. This report reveals dependence relationship between the progress of general electrochemical parameters and bacterial sulfate-reduction rate. The presented MFC design can be used for simultaneous sulfate purification of mining drainage wastewater and generation of renewable electricity

  3. One cell, one love: a journal for microbial research

    Didac Carmona-Gutierrez

    2014-01-01

    Full Text Available With their broad utility for biotechnology, their continuous menace as infectious pathogens, and as an integral part of our bodies (intestinal flora, unicellular organisms remain in the focus of global research. This interest has been further stimulated by the challenge to counteract the emergence of multi-resistant microbes, as well as by the recent advances in establishing unicellular organisms as valid models for human diseases. It is our great pleasure to launch the inaugural issue of Microbial Cell (MIC, an international, open-access, peer-reviewed journal dedicated to microbial research. MIC is committed to the publication of articles that deal with the characterization of unicellular organisms (or multicellular microorganisms in their response to internal and external stimuli and/or in the context of human health and disease. Thus, MIC covers heterogeneous topics in diverse areas ranging from microbial and general cell biology to molecular signaling, disease modeling and pathogen targeting. MIC’s Editorial Board counts with world-class leaders in a wide variety of fields, including microbiology, aging, evolution, biotechnology, ecology, biochemistry, infection biology, and human pathophysiology. We are convinced that MIC will appeal to readers from a broad scientific and medical background, including basic researchers, microbiologists, clinicians, educators and – we hope – policy makers as well as to any interested individual.

  4. Assessment of Microbial Fuel Cell Configurations and Power Densities

    Logan, Bruce E.; Wallack, Maxwell J; Kim, Kyoung-Yeol; He, Weihua; Feng, Yujie; Saikaly, Pascal

    2015-01-01

    Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

  5. Genome-enabled Modeling of Microbial Biogeochemistry using a Trait-based Approach. Does Increasing Metabolic Complexity Increase Predictive Capabilities?

    King, E.; Karaoz, U.; Molins, S.; Bouskill, N.; Anantharaman, K.; Beller, H. R.; Banfield, J. F.; Steefel, C. I.; Brodie, E.

    2015-12-01

    The biogeochemical functioning of ecosystems is shaped in part by genomic information stored in the subsurface microbiome. Cultivation-independent approaches allow us to extract this information through reconstruction of thousands of genomes from a microbial community. Analysis of these genomes, in turn, gives an indication of the organisms present and their functional roles. However, metagenomic analyses can currently deliver thousands of different genomes that range in abundance/importance, requiring the identification and assimilation of key physiologies and metabolisms to be represented as traits for successful simulation of subsurface processes. Here we focus on incorporating -omics information into BioCrunch, a genome-informed trait-based model that represents the diversity of microbial functional processes within a reactive transport framework. This approach models the rate of nutrient uptake and the thermodynamics of coupled electron donors and acceptors for a range of microbial metabolisms including heterotrophs and chemolithotrophs. Metabolism of exogenous substrates fuels catabolic and anabolic processes, with the proportion of energy used for cellular maintenance, respiration, biomass development, and enzyme production based upon dynamic intracellular and environmental conditions. This internal resource partitioning represents a trade-off against biomass formation and results in microbial community emergence across a fitness landscape. Biocrunch was used here in simulations that included organisms and metabolic pathways derived from a dataset of ~1200 non-redundant genomes reflecting a microbial community in a floodplain aquifer. Metagenomic data was directly used to parameterize trait values related to growth and to identify trait linkages associated with respiration, fermentation, and key enzymatic functions such as plant polymer degradation. Simulations spanned a range of metabolic complexities and highlight benefits originating from simulations

  6. Enhancement of electricity production by graphene oxide in soil microbial fuel cells and plant microbial fuel cells

    Yuko eGoto

    2015-04-01

    Full Text Available The effects of graphene oxide (GO on electricity generation in soil microbial fuel cells (SMFCs and plant microbial fuel cell (PMFCs were investigated. GO at concentrations ranging from 0 to 1.9 g•kg-1 was added to soil and reduced for 10 days under anaerobic incubation. All SMFCs (GO-SMFCs utilizing the soils incubated with GO produced electricity at a greater rate and in higher quantities than the SMFCs which did not contain GO. In fed-batch operations, the overall average electricity generation in GO-SMFCs containing 1.0 g•kg-1 of GO was 40 ± 19 mW•m-2, which was significantly higher than the value of 6.6 ± 8.9 mW•m-2 generated from GO-free SMFCs (p -2 of electricity after 27 days of operation. Collectively, this study demonstrates that GO added to soil can be microbially reduced in soil, and facilitates electron transfer to the anode in both SMFCs and PMFCs.

  7. Succession of the functional microbial communities and the metabolic functions in maize straw composting process.

    Wei, Huawei; Wang, Liuhong; Hassan, Muhammad; Xie, Bing

    2018-05-01

    Illumina MiSeq sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) were applied to study the dynamic changes and effects of microbial community structures as well as the metabolic function of bacterial community in maize straw composting process. Results showed that humic acid contents in loosely combined humus (HA1) and stably combined humus (HA2) increased after composting and Staphylococcus, Cellulosimicrobium and Ochrobactrum possibly participated in the transformation of the process. The bacterial communities differed in different stages of the composting. Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria were reported the dominant phyla throughout the process and the relative abundance of the dominant phyla varied significantly (p composting. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Influences of dissolved oxygen concentration on biocathodic microbial communities in microbial fuel cells.

    Rago, Laura; Cristiani, Pierangela; Villa, Federica; Zecchin, Sarah; Colombo, Alessandra; Cavalca, Lucia; Schievano, Andrea

    2017-08-01

    Dissolved oxygen (DO) at cathodic interface is a critical factor influencing microbial fuel cells (MFC) performance. In this work, three MFCs were operated with cathode under different DO conditions: i) air-breathing (A-MFC); ii) water-submerged (W-MFC) and iii) assisted by photosynthetic microorganisms (P-MFC). A plateau of maximum current was reached at 1.06±0.03mA, 1.48±0.06mA and 1.66±0.04mA, increasing respectively for W-MFC, P-MFC and A-MFC. Electrochemical and microbiological tools (Illumina sequencing, confocal microscopy and biofilm cryosectioning) were used to explore anodic and cathodic biofilm in each MFC type. In all cases, biocathodes improved oxygen reduction reaction (ORR) as compared to abiotic condition and A-MFC was the best performing system. Photosynthetic cultures in the cathodic chamber supplied high DO level, up to 16mg O2 L -1 , which sustained aerobic microbial community in P-MFC biocathode. Halomonas, Pseudomonas and other microaerophilic genera reached >50% of the total OTUs. The presence of sulfur reducing bacteria (Desulfuromonas) and purple non-sulfur bacteria in A-MFC biocathode suggested that the recirculation of sulfur compounds could shuttle electrons to sustain the reduction of oxygen as final electron acceptor. The low DO concentration limited the cathode in W-MFC. A model of two different possible microbial mechanisms is proposed which can drive predominantly cathodic ORR. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. IMGMD: A platform for the integration and standardisation of In silico Microbial Genome-scale Metabolic Models.

    Ye, Chao; Xu, Nan; Dong, Chuan; Ye, Yuannong; Zou, Xuan; Chen, Xiulai; Guo, Fengbiao; Liu, Liming

    2017-04-07

    Genome-scale metabolic models (GSMMs) constitute a platform that combines genome sequences and detailed biochemical information to quantify microbial physiology at the system level. To improve the unity, integrity, correctness, and format of data in published GSMMs, a consensus IMGMD database was built in the LAMP (Linux + Apache + MySQL + PHP) system by integrating and standardizing 328 GSMMs constructed for 139 microorganisms. The IMGMD database can help microbial researchers download manually curated GSMMs, rapidly reconstruct standard GSMMs, design pathways, and identify metabolic targets for strategies on strain improvement. Moreover, the IMGMD database facilitates the integration of wet-lab and in silico data to gain an additional insight into microbial physiology. The IMGMD database is freely available, without any registration requirements, at http://imgmd.jiangnan.edu.cn/database.

  10. High power density yeast catalyzed microbial fuel cells

    Ganguli, Rahul

    Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density

  11. Metabolic enzyme cost explains variable trade-offs between microbial growth rate and yield.

    Meike T Wortel

    2018-02-01

    Full Text Available Microbes may maximize the number of daughter cells per time or per amount of nutrients consumed. These two strategies correspond, respectively, to the use of enzyme-efficient or substrate-efficient metabolic pathways. In reality, fast growth is often associated with wasteful, yield-inefficient metabolism, and a general thermodynamic trade-off between growth rate and biomass yield has been proposed to explain this. We studied growth rate/yield trade-offs by using a novel modeling framework, Enzyme-Flux Cost Minimization (EFCM and by assuming that the growth rate depends directly on the enzyme investment per rate of biomass production. In a comprehensive mathematical model of core metabolism in E. coli, we screened all elementary flux modes leading to cell synthesis, characterized them by the growth rates and yields they provide, and studied the shape of the resulting rate/yield Pareto front. By varying the model parameters, we found that the rate/yield trade-off is not universal, but depends on metabolic kinetics and environmental conditions. A prominent trade-off emerges under oxygen-limited growth, where yield-inefficient pathways support a 2-to-3 times higher growth rate than yield-efficient pathways. EFCM can be widely used to predict optimal metabolic states and growth rates under varying nutrient levels, perturbations of enzyme parameters, and single or multiple gene knockouts.

  12. Cadmium (II) removal mechanisms in microbial electrolysis cells

    Colantonio, Natalie; Kim, Younggy, E-mail: younggy@mcmaster.ca

    2016-07-05

    Highlights: • Rapid removal of Cd(II) was achieved in 24 h using microbial electrolysis cells. • Cathodic reduction (electrodeposition) of Cd(II) cannot explain the rapid removal. • H{sub 2} evolution in microbial electrolysis cells increases local pH near the cathode. • High local pH induces Cd(OH){sub 2} and CdCO{sub 3} precipitation only with electric current. • Neutral pH caused by low current and depleted substrate dissolves the precipitated Cd. - Abstract: Cadmium is a toxic heavy metal, causing serious environmental and human health problems. Conventional methods for removing cadmium from wastewater are expensive and inefficient for low concentrations. Microbial electrolysis cells (MECs) can simultaneously treat wastewater, produce hydrogen gas, and remove heavy metals with low energy requirements. Lab-scale MECs were operated to remove cadmium under various electric conditions: applied voltages of 0.4, 0.6, 0.8, and 1.0 V; and a fixed cathode potential of −1.0 V vs. Ag/AgCl. Regardless of the electric condition, rapid removal of cadmium was demonstrated (50–67% in 24 h); however, cadmium concentration in solution increased after the electric current dropped with depleted organic substrate under applied voltage conditions. For the fixed cathode potential, the electric current was maintained even after substrate depletion and thus cadmium concentration did not increase. These results can be explained by three different removal mechanisms: cathodic reduction; Cd(OH){sub 2} precipitation; and CdCO{sub 3} precipitation. When the current decreased with depleted substrates, local pH at the cathode was no longer high due to slowed hydrogen evolution reaction (2H{sup +} + 2e{sup −} → H{sub 2}); thus, the precipitated Cd(OH){sub 2} and CdCO{sub 3} started dissolving. To prevent their dissolution, sufficient organic substrates should be provided when MECs are used for cadmium removal.

  13. Microbial electricity generation in rice paddy fields: recent advances and perspectives in rhizosphere microbial fuel cells.

    Kouzuma, Atsushi; Kaku, Nobuo; Watanabe, Kazuya

    2014-12-01

    Microbial fuel cells (MFCs) are devices that use living microbes for the conversion of organic matter into electricity. MFC systems can be applied to the generation of electricity at water/sediment interfaces in the environment, such as bay areas, wetlands, and rice paddy fields. Using these systems, electricity generation in paddy fields as high as ∼80 mW m(-2) (based on the projected anode area) has been demonstrated, and evidence suggests that rhizosphere microbes preferentially utilize organic exudates from rice roots for generating electricity. Phylogenetic and metagenomic analyses have been conducted to identify the microbial species and catabolic pathways that are involved in the conversion of root exudates into electricity, suggesting the importance of syntrophic interactions. In parallel, pot cultures of rice and other aquatic plants have been used for rhizosphere MFC experiments under controlled laboratory conditions. The findings from these studies have demonstrated the potential of electricity generation for mitigating methane emission from the rhizosphere. Notably, however, the presence of large amounts of organics in the rhizosphere drastically reduces the effect of electricity generation on methane production. Further studies are necessary to evaluate the potential of these systems for mitigating methane emission from rice paddy fields. We suggest that paddy-field MFCs represent a promising approach for harvesting latent energy of the natural world.

  14. Design of a microbial fuel cell and its transition to microbial electrolytic cell for hydrogen production by electrohydrogenesis.

    Gupta, Pratima; Parkhey, Piyush; Joshi, Komal; Mahilkar, Anjali

    2013-10-01

    Anaerobic bacteria were isolated from industrial wastewater and soil samples and tested for exoelectrogenic activity by current production in double chambered microbial fuel cell (MFC), which was further transitioned into a single chambered microbial electrolytic cell to test hydrogen production by electrohydrogenesis. Of all the cultures, the isolate from industrial water sample showed the maximum values for current = 0.161 mA, current density = 108.57 mA/m2 and power density = 48.85 mW/m2 with graphite electrode. Maximum voltage across the cell, however, was reported by the isolate from sewage water sample (506 mv) with copper as electrode. Tap water with KMnO4 was the best cathodic electrolyte as the highest values for all the measured MFC parameters were reported with it. Once the exoelectrogenic activity of the isolates was confirmed by current production, these were tested for hydrogen production in a single chambered microbial electrolytic cell (MEC) modified from the MFC. Hydrogen production was reported positive from co-culture of isolates of both the water samples and co-culture of one soil and one water sample. The maximum rate and yield of hydrogen production was 0.18 m3H2/m3/d and 3.2 mol H2/mol glucose respectively with total hydrogen production of 42.4 mL and energy recovery of 57.4%. Cumulative hydrogen production for a five day cycle of MEC operation was 0.16 m3H2/m3/d.

  15. Progress of air-breathing cathode in microbial fuel cells

    Wang, Zejie; Mahadevan, Gurumurthy Dummi; Wu, Yicheng; Zhao, Feng

    2017-07-01

    Microbial fuel cell (MFC) is an emerging technology to produce green energy and vanquish the effects of environmental contaminants. Cathodic reactions are vital for high electrical power density generated from MFCs. Recently tremendous attentions were paid towards developing high performance air-breathing cathodes. A typical air-breathing cathode comprises of electrode substrate, catalyst layer, and air-diffusion layer. Prior researches demonstrated that each component influenced the performance of air-breathing cathode MFCs. This review summarized the progress in development of the individual component and elaborated main factors to the performance of air-breathing cathode.

  16. Innovative microbial fuel cell for electricity production from anaerobic reactors

    Min, Booki; Angelidaki, Irini

    2008-01-01

    A submersible microbial fuel cell (SMFC) was developed by immersing an anode electrode and a cathode chamber in an anaerobic reactor. Domestic wastewater was used as the medium and the inoculum in the experiments. The SMFC could successfully generate a stable voltage of 0.428 ± 0.003 V with a fixed......, a large portion of voltage drop was caused by the ohmic (electrolyte) resistance of the medium present between two electrodes, although the two electrodes were closely positioned (about 3 cm distance; internal resistance = 35 ± 2 Ω). The open circuit potential (0.393 V vs. a standard hydrogen electrode...

  17. Reply to 'Comment on kinetic modeling of microbially-driven redox chemistry of subsurface environments: coupling transport, microbial metabolism and geochemistry' by J. Griffioen

    Hunter, K. S.; Van Cappellen, P.

    2000-01-01

    Our paper, 'Kinetic modeling of microbially-driven redox chemistry of subsurface environments: coupling transport, microbial metabolism and geochemistry' (Hunter et al., 1998), presents a theoretical exploration of biogeochemical reaction networks and their importance to the biogeochemistry of groundwater systems. As with any other model, the kinetic reaction-transport model developed in our paper includes only a subset of all physically, biologically and chemically relevant processes in subsurface environments. It considers aquifer systems where the primary energy source driving microbial activity is the degradation of organic matter. In addition to the primary biodegradation pathways of organic matter (i.e. respiration and fermentation), the redox chemistry of groundwaters is also affected by reactions not directly involving organic matter oxidation. We refer to the latter as secondary reactions. By including secondary redox reactions which consume reduced reaction products (e.g., Mn2+, FeS, H2S), and in the process compete with microbial heterotrophic populations for available oxidants (i.e. O2, NO3-, Mn(IV), Fe(III), SO42-), we predict spatio-temporal distributions of microbial activity which differ significantly from those of models which consider only the biodegradation reactions. That is, the secondary reactions have a significant impact on the distributions of the rates of heterotrophic and chemolithotrophic metabolic pathways. We further show that secondary redox reactions, as well as non-redox reactions, significantly influence the acid-base chemistry of groundwaters. The distributions of dissolved inorganic redox species along flowpaths, however, are similar in simulations with and without secondary reactions (see Figs. 3(b) and 7(b) in Hunter et al., 1998), indicating that very different biogeochemical reaction dynamics may lead to essentially the same chemical redox zonation of a groundwater system.

  18. Unusual metabolic diversity of hyperalkaliphilic microbial communities associated with subterranean serpentinization at The Cedars.

    Suzuki, Shino; Ishii, Shun'ichi; Hoshino, Tatsuhiko; Rietze, Amanda; Tenney, Aaron; Morrill, Penny L; Inagaki, Fumio; Kuenen, J Gijs; Nealson, Kenneth H

    2017-11-01

    Water from The Cedars springs that discharge from serpentinized ultramafic rocks feature highly basic (pH=~12), highly reducing (E h serpentinizing system, was dominated by several bacterial taxa from the phyla OD1 ('Parcubacteria') and Chloroflexi. Members of the GPS1 community had, for the most part, the smallest genomes reported for their respective taxa, and encoded only archaeal (A-type) ATP synthases or no ATP synthases at all. Furthermore, none of the members encoded respiration-related genes and some of the members also did not encode key biosynthesis-related genes. In contrast, BS5, fed by shallow water, appears to have a community driven by hydrogen metabolism and was dominated by a diverse group of Proteobacteria similar to those seen in many terrestrial serpentinization sites. Our findings indicated that the harsh ultrabasic geological setting supported unexpectedly diverse microbial metabolic strategies and that the deep-water-fed springs supported a community that was remarkable in its unusual metagenomic and genomic constitution.

  19. The effect of gluten on the host-microbial metabolism assessed by urinary metabolomics

    Roager, Henrik Munch; Frandsen, Henrik Lauritz; Gøbel, Rikke Juul

    A gluten-free diet clearly improves the life of patients with celiac disease, but the scientific evidence supporting possible health benefits of a gluten-free diet for non-celiac adults is limited. Therefore, as urine reflects the host and gut microbial metabolism, the study aimed to assess...... a gluten-rich (21.6±5.7g/day) or a gluten-poor (~1g/day) diet for 8 weeks, crossing over to the other diet after 6 weeks washout. Urine samples were standardised collected at the beginning and end of each diet intervention period and were analysed by gas chromatography mass spectrometry (GC-MS) and liquid...... the long-term metabolic effect of gluten on the urine metabolome of non-celiac individuals by a cross-over intervention study (gluten-poor and gluten rich, respectively) using a non-targeted metabolomics approach. Fifty-one non-celiac adult participants (30 female, 21 male) were randomized to either...

  20. In situ metabolism in halite endolithic microbial communities of the hyperarid Atacama Desert

    Alfonso F Davila

    2015-10-01

    Full Text Available The Atacama Desert of northern Chile is one of the driest regions on Earth, with areas that exclude plants and where soils have extremely low microbial biomass. However, in the driest parts of the desert there are microorganisms that colonize the interior of halite nodules in fossil continental evaporites, where they are sustained by condensation of atmospheric water triggered by the salt substrate. Using a combination of in situ observations of variable chlorophyll fluorescence and controlled laboratory experiments, we show that this endolithic community is capable of carbon fixation both through oxygenic photosynthesis and potentially ammonia oxidation. We also present evidence that photosynthetic activity is finely tuned to moisture availability and solar insolation and can be sustained for days, and perhaps longer, after a wetting event. This is the first demonstration of in situ active metabolism in the hyperarid core of the Atacama Desert, and it provides the basis for proposing a self-contained, endolithic community that relies exclusively on non-rainfall sources of water. Our results contribute to an increasing body of evidence that even in hyperarid environments active metabolism, adaptation and growth can occur in highly specialized microhabitats.

  1. Microbial Reverse Electrodialysis Cells for Synergistically Enhanced Power Production

    Kim, Younggy

    2011-07-01

    A new type of bioelectrochemical system for producing electrical power, called a microbial reverse-electrodialysis cell (MRC), was developed to increase voltages and power densities compared to those generated individually by microbial fuel cells (MFCs) or reverse electrodialysis (RED) systems. In RED systems, electrode overpotentials create significant energy losses due to thermodynamically unfavorable electrode reactions, and therefore a large number of stacked cells must be used to have significant energy recovery. This results in high capital costs for the large number of membranes, and increases energy losses from pumping water through a large number of cells. In an MRC, high overpotentials are avoided through oxidation of organic matter by exoelectrogenic bacteria on the anode and oxygen reduction on the cathode. An MRC containing only five pairs of RED cells, fed solutions typical of seawater (600 mM NaCl) and river water (12 mM NaCl) at 0.85 mL/min, produced up to 3.6 W/m2 (cathode surface area) and 1.2-1.3 V with acetate as a substrate. Pumping accounted for <2% of the produced power. A higher flow rate (1.55 mL/min) increased power densities up to 4.3 W/m2. COD removal was 98% with a Coulombic efficiency of 64%. Power production by the individual components was substantially lower with 0.7 W/m2 without salinity driven energy, and <0.015 W/m2 with reduced exoelectrogenic activity due to substrate depletion. These results show that the combination of an MFC and a RED stack synergistically increases performance relative to the individual systems, producing a new type of system that can be used to more efficiently capture salinity driven energy from seawater and river water. © 2011 American Chemical Society.

  2. Metabolic Potential and Activity in Fluids of the Coast Range Ophiolite Microbial Observatory, California, USA

    Hoehler, T.; Som, S.; Schrenk, M.; McCollom, T.; Cardace, D.

    2016-01-01

    Metabolic potential and activity associated with hydrogen and carbon monoxide were characterized in fluids sampled from the the Coast Range Ophiolite Microbial Observatory (CROMO). CROMO consists of two clusters of science-dedicated wells drilled to varying depths up to 35m in the actively serpentinizing, Jurassic-age Coast Range Ophiolite of Northern California, along with a suite of pre-existing monitoring wells at the same site. Consistent with the fluid chemistry observed in other serpentinizing systems, CROMO fluids are highly alkaline, with pH up to 12.5, high in methane, with concentrations up 1600 micromolar, and low in dissolved inorganic carbon (DIC), with concentrations of 10's to 100's of micromolar. CROMO is conspicuous for fluid H2 concentrations that are consistently sub-micromolar, orders of magnitude lower than is typical of other systems. However, higher H2 concentrations (10's -100's of micromolar) at an earlier stage of fluid chemical evolution are predicted by, or consistent with: thermodynamic models for fluid chemistry based on parent rock composition equivalent to local peridotite and with water:rock ratio constrained by observed pH; the presence of magnetite at several wt% in CROMO drill cores; and concentrations of formate and carbon monoxide that would require elevated H2 if formed in equilibrium with H2 and DIC. Calculated Gibbs energy changes for reaction of H2 and CO in each of several metabolisms, across the range of fluid composition encompassed by the CROMO wells, range from bioenergetically feasible (capable of driving ATP synthesis) to thermodynamically unfavorable. Active consumption relative to killed controls was observed for both CO and H2 during incubation of fluids from the pre-existing monitoring wells; in incubations of freshly cored solids, consumption was only observed in one sample set (corresponding to the lowest pH) out of three. The specific metabolisms by which H2 and CO are consumed remain to be determined.

  3. Microbial metabolic potential for carbon degradation and nutrient (nitrogen and phosphorus) acquisition in an ombrotrophic peatland.

    Lin, Xueju; Tfaily, Malak M; Green, Stefan J; Steinweg, J Megan; Chanton, Patrick; Imvittaya, Aopeau; Chanton, Jeffrey P; Cooper, William; Schadt, Christopher; Kostka, Joel E

    2014-06-01

    This study integrated metagenomic and nuclear magnetic resonance (NMR) spectroscopic approaches to investigate microbial metabolic potential for organic matter decomposition and nitrogen (N) and phosphorus (P) acquisition in soils of an ombrotrophic peatland in the Marcell Experimental Forest (MEF), Minnesota, USA. This analysis revealed vertical stratification in key enzymatic pathways and taxa containing these pathways. Metagenomic analyses revealed that genes encoding laccases and dioxygenases, involved in aromatic compound degradation, declined in relative abundance with depth, while the relative abundance of genes encoding metabolism of amino sugars and all four saccharide groups increased with depth in parallel with a 50% reduction in carbohydrate content. Most Cu-oxidases were closely related to genes from Proteobacteria and Acidobacteria, and type 4 laccase-like Cu-oxidase genes were >8 times more abundant than type 3 genes, suggesting an important and overlooked role for type 4 Cu-oxidase in phenolic compound degradation. Genes associated with sulfate reduction and methanogenesis were the most abundant anaerobic respiration genes in these systems, with low levels of detection observed for genes of denitrification and Fe(III) reduction. Fermentation genes increased in relative abundance with depth and were largely affiliated with Syntrophobacter. Methylocystaceae-like small-subunit (SSU) rRNA genes, pmoA, and mmoX genes were more abundant among methanotrophs. Genes encoding N2 fixation, P uptake, and P regulons were significantly enriched in the surface peat and in comparison to other ecosystems, indicating N and P limitation. Persistence of inorganic orthophosphate throughout the peat profile in this P-limiting environment indicates that P may be bound to recalcitrant organic compounds, thus limiting P bioavailability in the subsurface. Comparative metagenomic analysis revealed a high metabolic potential for P transport and starvation, N2 fixation, and

  4. Water type and irrigation time effects on microbial metabolism of a soil cultivated with Bermuda-grass Tifton 85

    Sandra Furlan Nogueira

    2011-06-01

    Full Text Available This study investigated the microbial metabolism in Bermuda-grass Tifton 85 areas after potable-water and effluent irrigation treatments. The experiment was carried out in Lins/SP with samples taken in the rainy and dry seasons (2006 after one year and three years of irrigation management, and set up on an entirely randomized block design with four treatments: C (control, without irrigation or fertilization, PW (potable water + 520 kg of N ha-1 year-1; TE3 and TE0 (treated effluent + 520 kg of N ha-1 year-1 for three years and one year, respectively. The parameters determined were: microbial biomass carbon, microbial activity, and metabolic quotient. Irrigation with wastewater after three years indicated no alteration in soil quality for C and ET3; for PW, a negative impact on soil quality (microbial biomass decrease suggested that water-potable irrigation in Lins is not an adequate option. Microbial activity alterations observed in TE0 characterize a priming effect.

  5. Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

    Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

    2017-03-01

    This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community.

  6. Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

    Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

    2017-01-01

    This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community. PMID:28300176

  7. In Situ Ecophysiology of Microbial Biofilm Communities Analyzed by CMEIAS Computer-Assisted Microscopy at Single-Cell Resolution

    Youssef G. Yanni

    2013-06-01

    Full Text Available This paper describes the utility of CMEIAS (Center for Microbial Ecology Image Analysis System computer-assisted microscopy to extract data from accurately segmented images that provide 63 different insights into the ecophysiology of microbial populations and communities within biofilms and other habitats. Topics include quantitative assessments of: (i morphological diversity as an indicator of impacts that substratum physicochemistries have on biofilm community structure and dominance-rarity relationships among populations; (ii morphotype-specific distributions of biovolume body size that relate microbial allometric scaling, metabolic activity and growth physiology; (iii fractal geometry of optimal cellular positioning for efficient utilization of allocated nutrient resources; (iv morphotype-specific stress responses to starvation, environmental disturbance and bacteriovory predation; (v patterns of spatial distribution indicating positive and negative cell–cell interactions affecting their colonization behavior; and (vi significant methodological improvements to increase the accuracy of color-discriminated ecophysiology, e.g., differentiation of cell viability based on cell membrane integrity, cellular respiratory activity, phylogenetically differentiated substrate utilization, and N-acyl homoserine lactone-mediated cell–cell communication by bacteria while colonizing plant roots. The intensity of these ecophysiological attributes commonly varies at the individual cell level, emphasizing the importance of analyzing them at single-cell resolution and the proper spatial scale at which they occur in situ.

  8. Electrode materials for microbial fuel cells: nanomaterial approach

    Mustakeem, Mustakeem

    2015-11-05

    Microbial fuel cell (MFC) technology has the potential to become a major renewable energy resource by degrading organic pollutants in wastewater. The performance of MFC directly depends on the kinetics of the electrode reactions within the fuel cell, with the performance of the electrodes heavily influenced by the materials they are made from. A wide range of materials have been tested to improve the performance of MFCs. In the past decade, carbon-based nanomaterials have emerged as promising materials for both anode and cathode construction. Composite materials have also shown to have the potential to become materials of choice for electrode manufacture. Various transition metal oxides have been investigated as alternatives to conventional expensive metals like platinum for oxygen reduction reaction. In this review, different carbon-based nanomaterials and composite materials are discussed for their potential use as MFC electrodes.

  9. Electrode materials for microbial fuel cells: nanomaterial approach

    Mustakeem, Mustakeem

    2015-01-01

    Microbial fuel cell (MFC) technology has the potential to become a major renewable energy resource by degrading organic pollutants in wastewater. The performance of MFC directly depends on the kinetics of the electrode reactions within the fuel cell, with the performance of the electrodes heavily influenced by the materials they are made from. A wide range of materials have been tested to improve the performance of MFCs. In the past decade, carbon-based nanomaterials have emerged as promising materials for both anode and cathode construction. Composite materials have also shown to have the potential to become materials of choice for electrode manufacture. Various transition metal oxides have been investigated as alternatives to conventional expensive metals like platinum for oxygen reduction reaction. In this review, different carbon-based nanomaterials and composite materials are discussed for their potential use as MFC electrodes.

  10. The Role of Soil Organic Matter, Nutrients, and Microbial Community Structure on the Performance of Microbial Fuel Cells

    Rooney-Varga, J. N.; Dunaj, S. J.; Vallino, J. J.; Hines, M. E.; Gay, M.; Kobyljanec, C.

    2011-12-01

    Microbial fuel cells (MFCs) offer the potential for generating electricity, mitigating greenhouse gas emissions, and bioremediating pollutants through utilization of a plentiful, natural, and renewable resource: soil organic carbon. In the current study, we analyzed microbial community structure, MFC performance, and soil characteristics in different microhabitats (bulk soil, anode, and cathode) within MFCs constructed from agricultural or forest soils in order to determine how soil type and microbial dynamics influence MFC performance. MFCs were constructed with soils from agricultural and hardwood forest sites at Harvard Forest (Petersham, MA). The bulk soil characteristics were analyzed, including polyphenols, short chain fatty acids, total organic C and N, abiotic macronutrients, N and P mineralization rates, CO2 respiration rates, and MFC power output. Microbial community structure of the anodes, cathodes, and bulk soils was determined with molecular fingerprinting methods, which included terminal restriction length polymorphism (T-RFLP) analysis and 16S rRNA gene sequencing analysis. Our results indicated that MFCs constructed from agricultural soil had power output about 17 times that of forest soil-based MFCs and respiration rates about 10 times higher than forest soil MFCs. Agricultural soil MFCs had lower C:N ratios, polyphenol content, and acetate concentrations than forest soil MFCs, suggesting that active agricultural MFC microbial communities were supported by higher quality organic carbon. Microbial community profile data indicate that the microbial communities at the anode of the high power MFCs were less diverse than in low power MFCs and were dominated by Deltaproteobacteria, Geobacter, and, to a lesser extent, Clostridia, while low-power MFC anode communities were dominated by Clostridia. These data suggest that the presence of organic carbon substrate (acetate) was not the major limiting factor in selecting for highly electrogenic microbial

  11. From gametogenesis and stem cells to cancer: common metabolic themes.

    Pereira, Sandro L; Rodrigues, Ana Sofia; Sousa, Maria Inês; Correia, Marcelo; Perestrelo, Tânia; Ramalho-Santos, João

    2014-01-01

    Both pluripotent stem cells (PSCs) and cancer cells have been described as having similar metabolic pathways, most notably a penchant for favoring glycolysis even under aerobiosis, suggesting common themes that might be explored for both stem cell differentiation and anti-oncogenic purposes. A search of the scientific literature available in the PubMed/Medline was conducted for studies on metabolism and mitochondrial function related to gametogenesis, early development, stem cells and cancers in the reproductive system, notably breast, prostate, ovarian and testicular cancers. Both PSCs and some types of cancer cells, particularly reproductive cancers, were found to obtain energy mostly by glycolysis, often reducing mitochondrial activity and oxidative phosphorylation. This strategy links proliferating cells, allowing for the biosynthesis reactions necessary for cell division. Interventions that affect metabolic pathways, and force cells to change their preferences, can lead to shifts in cell status, increasing either pluripotency or differentiation of stem cells, and causing cancer cells to become more or less aggressive. Interestingly metabolic changes in many cases seemed to lead to cell transformation, not necessarily follow it, suggesting a direct role of metabolic choices in influencing the (epi)genetic program of different cell types. There are uncanny similarities between PSCs and cancer cells at the metabolic level. Furthermore, metabolism may also play a direct role in cell status and targeting metabolic pathways could therefore be a promising strategy for both the control of cancer cell proliferation and the regulation of stem cell physiology, in terms of manipulating stem cells toward relevant phenotypes that may be important for tissue engineering, or making cancer cells become less tumorigenic. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For

  12. Mineralogical controls on surface colonization by sulfur-metabolizing microbial communities

    Jones, A. A.; Bennett, P.

    2012-12-01

    When characterizing microbial diversity and the microbial ecosystem of the shallow subsurface the mineral matrix is generally assumed to be homogenous and unreactive. We report here experimental evidence that microorganisms colonize rock surfaces according to the rock's chemistry and the organism's metabolic requirements and tolerances. We investigated this phenomenon using laboratory biofilm reactors with both a pure culture of sulfur-oxidizing Thiothrix unzii and a mixed environmental sulfur-metabolizing community from Lower Kane, Cave, WY, USA. Reactors contained rock and mineral chips (calcite, albite, microcline, quartz, chert, Madison Limestone (ML), Madison Dolostone (MD), and basalt) amended with one of the two inoculants. Biomass of attached microorganisms on each mineral surface was quantified. The 16S rRNA of attached microbial communities were compared using Roche FLX and Titanium 454 next generation pyrosequencing. A primary controlling factor on taxonomy of attached microorganisms in both pure and mixed culture experiments was mineral buffering capacity. In mixed culture experiments acid-buffering carbonates were preferentially colonized by neutrophilic sulfur-oxidizing microorganisms (~18% to ~27% of microorganisms), while acidophilic sulfur-oxidizing microorganisms colonized non-buffering quartz exclusively (~46% of microorganisms). The nutrient content of the rock was a controlling factor on biomass accumulation, with neutrophilic organisms selecting between carbonate surfaces of equivalent buffer capacities according to the availability of phosphate. Dry biomass on ML was 17.8 ± 2.3 mg/cm2 and MD was 20.6 ± 6.8 mg/cm2; while nutrient poor calcite accumulated 2.4 ± 0.3 mg/cm2. Biomass accumulation was minimal on non-buffering nutrient-limited surfaces. These factors are countered by the competitive exclusion of some populations. A pure culture of T. unzii preferentially colonizes carbonates while a very closely related Thiothrix spp is excluded

  13. Aging, metabolism and stem cells: Spotlight on muscle stem cells.

    García-Prat, Laura; Muñoz-Cánoves, Pura

    2017-04-15

    All tissues and organs undergo a progressive regenerative decline as they age. This decline has been mainly attributed to loss of stem cell number and/or function, and both stem cell-intrinsic changes and alterations in local niches and/or systemic environment over time are known to contribute to the stem cell aging phenotype. Advancing in the molecular understanding of the deterioration of stem cell cells with aging is key for targeting the specific causes of tissue regenerative dysfunction at advanced stages of life. Here, we revise exciting recent findings on why stem cells age and the consequences on tissue regeneration, with a special focus on regeneration of skeletal muscle. We also highlight newly identified common molecular pathways affecting diverse types of aging stem cells, such as altered proteostasis, metabolism, or senescence entry, and discuss the questions raised by these findings. Finally, we comment on emerging stem cell rejuvenation strategies, principally emanating from studies on muscle stem cells, which will surely burst tissue regeneration research for future benefit of the increasing human aging population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Nitrification-driven forms of nitrogen metabolism in microbial mat communities thriving along an ammonium-enriched subsurface geothermal stream

    Nishizawa, Manabu; Koba, Keisuke; Makabe, Akiko; Yoshida, Naohiro; Kaneko, Masanori; Hirao, Shingo; Ishibashi, Jun-ichiro; Yamanaka, Toshiro; Shibuya, Takazo; Kikuchi, Tohru; Hirai, Miho; Miyazaki, Junichi; Nunoura, Takuro; Takai, Ken

    2013-07-01

    We report here the concurrence and interaction among forms of nitrogen metabolism in thermophilic microbial mat communities that developed in an ammonium-abundant subsurface geothermal stream. First, the physical and chemical conditions of the stream water at several representative microbial mat habitats (including upper, middle and downstream sites) were characterized. A thermodynamic calculation using these physical and chemical conditions predicted that nitrification consisting of ammonia and nitrite oxidations would provide one of the largest energy yields of chemolithotrophic metabolisms. Second, near-complete prokaryotic 16S rRNA gene clone analysis was conducted for representative microbial mat communities at the upper, middle and downstream sites. The results indicated a dynamic shift in the 16S rRNA gene phylotype composition through physical and chemical variations of the stream water. The predominant prokaryotic components varied from phylotypes related to hydrogeno (H2)- and thio (S)-trophic Aquificales, thermophilic methanotrophs and putative ammonia-oxidizing Archaea (AOA) located upstream (72 °C) to the phylotypes affiliated with putative AOA and nitrite-oxidizing bacteria (NOB) located at the middle and downstream sites (65 and 57 °C, respectively). In addition, the potential in situ metabolic activities of different forms of nitrogen metabolism were estimated through laboratory experiments using bulk microbial mat communities. Finally, the compositional and isotopic variation in nitrogen compounds was investigated in the stream water flowing over the microbial mats and in the interstitial water inside the mats. Although the stream water was characterized by a gradual decrease in the total ammonia concentration (ΣNH3: the sum of ammonia and ammonium concentrations) and a gradual increase in the total concentration of nitrite and nitrate (NO2- + NO3-), the total inorganic nitrogen concentration (TIN: the sum of ΣNH3, NO2- and NO3- concentrations

  15. Soil microbial metabolic quotient (qCO2) of twelve ecosystems of Mt. Kilimanjaro

    Pabst, Holger; Gerschlauer, Friederike; Kiese, Ralf; Kuzyakov, Yakov

    2014-05-01

    Soil organic carbon, microbial biomass carbon (MBC) and the metabolic quotient qCO2 - as sensitive and important parameters for soil fertility and C turnover - are strongly affected by land-use changes all over the world. These effects are particularly distinct upon conversion of natural to agricultural ecosystems due to very fast carbon (C) and nutrient cycles and high vulnerability, especially in the tropics. In this study, we used an elevational gradient on Mt. Kilimanjaro to investigate the effects of land-use change and elevation on Corg, MBC and qCO2. Down to a soil depth of 18 cm we compared 4 natural (Helichrysum, Erica forest, Podocarpus forest, Ocotea forest), 5 seminatural (disturbed Podocarpus forest, disturbed Ocotea forest, lower montane forest, grassland, savannah), 1 sustainably used (homegarden) and 2 intensively used ecosystems (coffee plantation, maize field) on an elevation gradient from 950 to 3880 m a.s.l.. Using an incubation device, soil CO2-efflux of 18 cm deep soil cores was measured under field moist conditions and mean annual temperature. MBC to Corg ratios varied between 0.7 and 2.3%. qCO2 increased with magnitude of the disturbance, albeit this effect decreased with elevation. Following the annual precipitation of the ecosystems, both, Corg and MBC showed a hum-shaped distribution with elevation, whereas their maxima were between 2500 and 3000 m a.s.l.. Additionaly, Corg and MBC contents were significantly reduced in intensively used agricultural systems. We conclude that the soil microbial biomass and its activity in Mt. Kilimanjaro ecosystems are strongly altered by land-use. This effect is more distinct in lower than in higher elevated ecosystems and strongly dependent on the magnitude of disturbance.

  16. Genomic Sequencing of Single Microbial Cells from Environmental Samples

    Ishoey, Thomas; Woyke, Tanja; Stepanauskas, Ramunas; Novotny, Mark; Lasken, Roger S.

    2008-02-01

    Recently developed techniques allow genomic DNA sequencing from single microbial cells [Lasken RS: Single-cell genomic sequencing using multiple displacement amplification, Curr Opin Microbiol 2007, 10:510-516]. Here, we focus on research strategies for putting these methods into practice in the laboratory setting. An immediate consequence of single-cell sequencing is that it provides an alternative to culturing organisms as a prerequisite for genomic sequencing. The microgram amounts of DNA required as template are amplified from a single bacterium by a method called multiple displacement amplification (MDA) avoiding the need to grow cells. The ability to sequence DNA from individual cells will likely have an immense impact on microbiology considering the vast numbers of novel organisms, which have been inaccessible unless culture-independent methods could be used. However, special approaches have been necessary to work with amplified DNA. MDA may not recover the entire genome from the single copy present in most bacteria. Also, some sequence rearrangements can occur during the DNA amplification reaction. Over the past two years many research groups have begun to use MDA, and some practical approaches to single-cell sequencing have been developed. We review the consensus that is emerging on optimum methods, reliability of amplified template, and the proper interpretation of 'composite' genomes which result from the necessity of combining data from several single-cell MDA reactions in order to complete the assembly. Preferred laboratory methods are considered on the basis of experience at several large sequencing centers where >70% of genomes are now often recovered from single cells. Methods are reviewed for preparation of bacterial fractions from environmental samples, single-cell isolation, DNA amplification by MDA, and DNA sequencing.

  17. Systems Level Dissection of Anaerobic Methane Cycling: Quantitative Measurements of Single Cell Ecophysiology, Genetic Mechanisms, and Microbial Interactions

    Orphan, Victoria [California Inst. of Technology (CalTech), Pasadena, CA (United States); Tyson, Gene [University of Queensland, Brisbane Australia; Meile, Christof [University of Georgia, Athens, Georgia; McGlynn, Shawn [California Inst. of Technology (CalTech), Pasadena, CA (United States); Yu, Hang [California Inst. of Technology (CalTech), Pasadena, CA (United States); Chadwick, Grayson [California Inst. of Technology (CalTech), Pasadena, CA (United States); Marlow, Jeffrey [California Inst. of Technology (CalTech), Pasadena, CA (United States); Trembath-Reichert, Elizabeth [California Inst. of Technology (CalTech), Pasadena, CA (United States); Dekas, Anne [California Inst. of Technology (CalTech), Pasadena, CA (United States); Hettich, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pan, Chongle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellisman, Mark [University of California San Diego; Hatzenpichler, Roland [California Inst. of Technology (CalTech), Pasadena, CA (United States); Skennerton, Connor [California Inst. of Technology (CalTech), Pasadena, CA (United States); Scheller, Silvan [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2017-12-25

    The global biological CH4 cycle is largely controlled through coordinated and often intimate microbial interactions between archaea and bacteria, the majority of which are still unknown or have been only cursorily identified. Members of the methanotrophic archaea, aka ‘ANME’, are believed to play a major role in the cycling of methane in anoxic environments coupled to sulfate, nitrate, and possibly iron and manganese oxides, frequently forming diverse physical and metabolic partnerships with a range of bacteria. The thermodynamic challenges overcome by the ANME and their bacterial partners and corresponding slow rates of growth are common characteristics in anaerobic ecosystems, and, in stark contrast to most cultured microorganisms, this type of energy and resource limited microbial lifestyle is likely the norm in the environment. While we have gained an in-depth systems level understanding of fast-growing, energy-replete microorganisms, comparatively little is known about the dynamics of cell respiration, growth, protein turnover, gene expression, and energy storage in the slow-growing microbial majority. These fundamental properties, combined with the observed metabolic and symbiotic versatility of methanotrophic ANME, make these cooperative microbial systems a relevant (albeit challenging) system to study and for which to develop and optimize culture-independent methodologies, which enable a systems-level understanding of microbial interactions and metabolic networks. We used an integrative systems biology approach to study anaerobic sediment microcosms and methane-oxidizing bioreactors and expanded our understanding of the methanotrophic ANME archaea, their interactions with physically-associated bacteria, ecophysiological characteristics, and underlying genetic basis for cooperative microbial methane-oxidation linked with different terminal electron acceptors. Our approach is inherently multi-disciplinary and multi-scaled, combining transcriptional and

  18. Energy-positive wastewater treatment and desalination in an integrated microbial desalination cell (MDC)-microbial electrolysis cell (MEC)

    Li, Yan; Styczynski, Jordyn; Huang, Yuankai; Xu, Zhiheng; McCutcheon, Jeffrey; Li, Baikun

    2017-07-01

    Simultaneous removal of nitrogen in municipal wastewater, metal in industrial wastewater and saline in seawater was achieved in an integrated microbial desalination cell-microbial electrolysis cell (MDC-MEC) system. Batch tests showed that more than 95.1% of nitrogen was oxidized by nitrification in the cathode of MDC and reduced by heterotrophic denitrification in the anode of MDC within 48 h, leading to the total nitrogen removal rate of 4.07 mg L-1 h-1. Combining of nitrogen removal and desalination in MDC effectively solved the problem of pH fluctuation in anode and cathode, and led to 63.7% of desalination. Power generation of MDC (293.7 mW m-2) was 2.9 times higher than the one without salt solution. The electric power of MDC was harvested by a capacitor circuit to supply metal reduction in a MEC, and 99.5% of lead (II) was removed within 48 h. A kinetic MDC model was developed to elucidate the correlation of voltage output and desalination efficiency. Ratio of wastewater and sea water was calculated for MDC optimal operation. Energy balance of nutrient removal, metal removal and desalination in the MDC-MEC system was positive (0.0267 kW h m-3), demonstrating the promise of utilizing low power output of MDCs.

  19. Integrated hydrogen production process from cellulose by combining dark fermentation, microbial fuel cells, and a microbial electrolysis cell

    Wang, Aijie

    2011-03-01

    Hydrogen gas production from cellulose was investigated using an integrated hydrogen production process consisting of a dark fermentation reactor and microbial fuel cells (MFCs) as power sources for a microbial electrolysis cell (MEC). Two MFCs (each 25mL) connected in series to an MEC (72mL) produced a maximum of 0.43V using fermentation effluent as a feed, achieving a hydrogen production rate from the MEC of 0.48m 3 H 2/m 3/d (based on the MEC volume), and a yield of 33.2mmol H 2/g COD removed in the MEC. The overall hydrogen production for the integrated system (fermentation, MFC and MEC) was increased by 41% compared with fermentation alone to 14.3mmol H 2/g cellulose, with a total hydrogen production rate of 0.24m 3 H 2/m 3/d and an overall energy recovery efficiency of 23% (based on cellulose removed) without the need for any external electrical energy input. © 2010 Elsevier Ltd.

  20. Integrated hydrogen production process from cellulose by combining dark fermentation, microbial fuel cells, and a microbial electrolysis cell.

    Wang, Aijie; Sun, Dan; Cao, Guangli; Wang, Haoyu; Ren, Nanqi; Wu, Wei-Min; Logan, Bruce E

    2011-03-01

    Hydrogen gas production from cellulose was investigated using an integrated hydrogen production process consisting of a dark fermentation reactor and microbial fuel cells (MFCs) as power sources for a microbial electrolysis cell (MEC). Two MFCs (each 25 mL) connected in series to an MEC (72 mL) produced a maximum of 0.43 V using fermentation effluent as a feed, achieving a hydrogen production rate from the MEC of 0.48 m(3) H(2)/m(3)/d (based on the MEC volume), and a yield of 33.2 mmol H(2)/g COD removed in the MEC. The overall hydrogen production for the integrated system (fermentation, MFC and MEC) was increased by 41% compared with fermentation alone to 14.3 mmol H(2)/g cellulose, with a total hydrogen production rate of 0.24 m(3) H(2)/m(3)/d and an overall energy recovery efficiency of 23% (based on cellulose removed) without the need for any external electrical energy input. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Biotechnological Aspects of Microbial Extracellular Electron Transfer

    Kato, Souichiro

    2015-01-01

    Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

  2. MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process.

    Araujo, Pablo Granda; Gras, Anna; Ginovart, Marta

    2016-01-01

    Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs) using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics) can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4 (+), NO3 (-), NO2 (-), N2) to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc). MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

  3. MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process

    Pablo Araujo Granda

    2016-01-01

    Full Text Available Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4+, NO3−, NO2−, N2 to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc. MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

  4. The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent

    Li, Xiaohu; Zhang, Ruizhe; Qian, Yawei

    2017-01-01

    The impact of different anode acclimation methods for enhancing hydrogen production in microbial electrolysis cell (MEC) was investigated in this study. The anodes were first acclimated in microbial fuel cells using acetate, butyrate and corn stalk fermentation effluent (CSFE) as substrate before...

  5. Microfabricated microbial fuel cell arrays reveal electrochemically active microbes.

    Huijie Hou

    Full Text Available Microbial fuel cells (MFCs are remarkable "green energy" devices that exploit microbes to generate electricity from organic compounds. MFC devices currently being used and studied do not generate sufficient power to support widespread and cost-effective applications. Hence, research has focused on strategies to enhance the power output of the MFC devices, including exploring more electrochemically active microbes to expand the few already known electricigen families. However, most of the MFC devices are not compatible with high throughput screening for finding microbes with higher electricity generation capabilities. Here, we describe the development of a microfabricated MFC array, a compact and user-friendly platform for the identification and characterization of electrochemically active microbes. The MFC array consists of 24 integrated anode and cathode chambers, which function as 24 independent miniature MFCs and support direct and parallel comparisons of microbial electrochemical activities. The electricity generation profiles of spatially distinct MFC chambers on the array loaded with Shewanella oneidensis MR-1 differed by less than 8%. A screen of environmental microbes using the array identified an isolate that was related to Shewanella putrefaciens IR-1 and Shewanella sp. MR-7, and displayed 2.3-fold higher power output than the S. oneidensis MR-1 reference strain. Therefore, the utility of the MFC array was demonstrated.

  6. Control of malodorous hydrogen sulfide compounds using microbial fuel cell.

    Eaktasang, Numfon; Min, Hyeong-Sik; Kang, Christina; Kim, Han S

    2013-10-01

    In this study, a microbial fuel cell (MFC) was used to control malodorous hydrogen sulfide compounds generated from domestic wastewaters. The electricity production demonstrated a distinct pattern of a two-step increase during 170 h of system run: the first maximum current density was 118.6 ± 7.2 mA m⁻² followed by a rebound of current density increase, reaching the second maximum of 176.8 ± 9.4 mA m⁻². The behaviors of the redox potential and the sulfate level in the anode compartment indicated that the microbial production of hydrogen sulfide compounds was suppressed in the first stage, and the hydrogen sulfide compounds generated from the system were removed effectively as a result of their electrochemical oxidation, which contributed to the additional electricity production in the second stage. This was also directly supported by sulfur deposits formed on the anode surface, which was confirmed by analyses on those solids using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy as well as an elemental analyzer. To this end, the overall reduction efficiencies for HS⁻ and H₂S(g) were as high as 67.5 and 96.4 %, respectively. The correlations among current density, redox potential, and sulfate level supported the idea that the electricity signal generated in the MFC can be utilized as a potential indicator of malodor control for the domestic wastewater system.

  7. Random distribution of nucleoli in metabolic cells

    Beckman, R.J.; Waterman, M.S.

    1977-01-01

    Hasofer (1974) has studied a probabilistic model for the fusion of nucleoli in metabolic cells. The nucleoli are uniformly distributed at points in the nucleus, assumed to be a sphere. The nucleoli grow from a point to a maximum size during interphase, and fusion is said to occur if the nucleoli touch. For this model, Hasofer calculated the probability of fusion and found it much smaller than experimental data would indicate. Experimental data of this type is taken by use of a microscope where a two-dimensional view or projection of the three-dimensional cell is obtained. Hasofer implicitly assumes that actual fusion can be distinguished from the case where the two nucleoli do not touch but their two-dimensional projections overlap. It is assumed, in this letter, that these two cases cannot be distinguished. The probability obtained by Beckman and Waterman is larger than Hasofer's and a much better fit to the experimental data is obtained. Even if true fusion can be unfailingly distinguished from overlap of the two-dimensional projections, it is hoped that these calculations will allow someone to propose the correct (non-uniform) model. It is concluded, for the assumptions used, that there is not sufficient evidence to reject the hypothesis of uniform distribution of the nucleoli.

  8. A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production.

    Liu, Guangli; Zhou, Ying; Luo, Haiping; Cheng, Xing; Zhang, Renduo; Teng, Wenkai

    2015-12-01

    The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4 ± 0.6 mmol/Lh) and the lowest energy consumption (0.35 ± 0.14 kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Conjugated oligoelectrolyte represses hydrogen oxidation by Geobacter sulfurreducens in microbial electrolysis cells

    Liu, Jia; Hou, Huijie; Chen, Xiaofen; Bazan, Guillermo C.; Kashima, Hiroyuki; Logan, Bruce

    2015-01-01

    © 2015 Elsevier B.V. A conjugated oligoelectrolyte (COE), which spontaneously aligns within cell membranes, was shown to completely inhibit H2 uptake by Geobacter sulfurreducens in microbial electrolysis cells. Coulombic efficiencies that were 490

  10. Polymer Separators for High-Power, High-Efficiency Microbial Fuel Cells

    Chen, Guang; Wei, Bin; Luo, Yong; Logan, Bruce E.; Hickner, Michael A.

    2012-01-01

    Microbial fuel cells (MFCs) with hydrophilic poly(vinyl alcohol) (PVA) separators showed higher Coulombic efficiencies (94%) and power densities (1220 mW m-2) than cells with porous glass fiber separators or reactors without a separator after 32

  11. Microbial fuel cell treatment of ethanol fermentation process water

    Borole, Abhijeet P [Knoxville, TN

    2012-06-05

    The present invention relates to a method for removing inhibitor compounds from a cellulosic biomass-to-ethanol process which includes a pretreatment step of raw cellulosic biomass material and the production of fermentation process water after production and removal of ethanol from a fermentation step, the method comprising contacting said fermentation process water with an anode of a microbial fuel cell, said anode containing microbes thereon which oxidatively degrade one or more of said inhibitor compounds while producing electrical energy or hydrogen from said oxidative degradation, and wherein said anode is in electrical communication with a cathode, and a porous material (such as a porous or cation-permeable membrane) separates said anode and cathode.

  12. Applications of Graphene-Modified Electrodes in Microbial Fuel Cells

    Fei Yu

    2016-09-01

    Full Text Available Graphene-modified materials have captured increasing attention for energy applications due to their superior physical and chemical properties, which can significantly enhance the electricity generation performance of microbial fuel cells (MFC. In this review, several typical synthesis methods of graphene-modified electrodes, such as graphite oxide reduction methods, self-assembly methods, and chemical vapor deposition, are summarized. According to the different functions of the graphene-modified materials in the MFC anode and cathode chambers, a series of design concepts for MFC electrodes are assembled, e.g., enhancing the biocompatibility and improving the extracellular electron transfer efficiency for anode electrodes and increasing the active sites and strengthening the reduction pathway for cathode electrodes. In spite of the challenges of MFC electrodes, graphene-modified electrodes are promising for MFC development to address the reduction in efficiency brought about by organic waste by converting it into electrical energy.

  13. Study of charge transfer reactions in a microbial fuel cell

    Martin, E.; Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Chimique; National Research Council of Canada, Montreal, PQ (Canada). Biotechnology Research Inst.; Tartakovsky, B. [National Research Council of Canada, Montreal, PQ (Canada). Biotechnology Research Inst.

    2008-07-01

    Electron transfer reactions in a microbial fuel cell (MFC) were evaluated. The MFC was inoculated with anaerobic mesophilic sludge and operated with carbon felt, carbon cloth, and platinum (Pt) coated carbon cloth. The MFC was then fed with either acetate or glucose as a source of fuel and operated at a temperature of 25 degrees C and a pH of 7. Scanning electron microscopy (SEM) micrographs demonstrated that the micro-organisms colonized the anodes. Cyclic voltammetry and polarization tests were conducted using different fractions of the anodophilic biofilm in order to determine charge transfer routes. The study characterized the electron transfer mechanisms used by the exoelectrogenic micro-organisms to produce electricity. It was concluded that further research is needed to characterize reaction transfer routes. 2 refs., 1 fig.

  14. COD removal characteristics in air-cathode microbial fuel cells

    Zhang, Xiaoyuan

    2015-01-01

    © 2014 Elsevier Ltd. Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs), substrate removal rates were compared in MFCs fed a single, readily biodegradable compound (acetate) or domestic wastewater (WW). Removal rates based on initial test conditions fit first-order kinetics, but rate constants varied with circuit resistance. With filtered WW (100Ω), the rate constant was 0.18h- 1, which was higher than acetate or filtered WW with an open circuit (0.10h- 1), but CEs were much lower (15-24%) than acetate. With raw WW (100Ω), COD removal proceeded in two stages: a fast removal stage with high current production, followed by a slower removal with little current. While using MFCs increased COD removal rate due to current generation, secondary processes will be needed to reduce COD to levels suitable for discharge.

  15. Scaling up microbial fuel cells and other bioelectrochemical systems

    Logan, Bruce E.

    2009-12-15

    Scientific research has advanced on different microbial fuel cell (MFC) technologies in the laboratory at an amazing pace, with power densities having reached over 1 kW/m3 (reactor volume) and to 6.9 W/m2 (anode area) under optimal conditions. The main challenge is to bring these technologies out of the laboratory and engineer practical systems for bioenergy production at larger scales. Recent advances in new types of electrodes, a better understanding of the impact of membranes and separators on performance of these systems, and results from several new pilot-scale tests are all good indicators that commercialization of the technology could be possible within a few years. Some of the newest advances and future challenges are reviewed here with respect to practical applications of these MFCs for renewable energy production and other applications. © 2009 Springer-Verlag.

  16. Energy harvesting influences electrochemical performance of microbial fuel cells

    Lobo, Fernanda Leite; Wang, Xin; Ren, Zhiyong Jason

    2017-07-01

    Microbial fuel cells (MFCs) can be effective power sources for remote sensing, wastewater treatment and environmental remediation, but their performance needs significant improvement. This study systematically analyzes how active harvesting using electrical circuits increased MFC system outputs as compared to passive resistors not only in the traditional maximal power point (MPP) but also in other desired operating points such as the maximum current point (MCP) and the maximum voltage point (MVP). Results show that active harvesting in MPP increased power output by 81-375% and active harvesting in MCP increased Coulombic efficiency by 207-805% compared with resisters operated at the same points. The cyclic voltammograms revealed redox potential shifts and supported the performance data. The findings demonstrate that active harvesting is a very effective approach to improve MFC performance across different operating points.

  17. Microbial Fuel Cell Possibilities on American Indian Tribal Lands

    Cameron, Kimberlynn [South Dakota School of Mines and Technology, Rapid City, SD (United States)

    2016-10-01

    The purpose of this paper is to present a brief background of tribal reservations, the process of how Microbial Fuel Cells (MFCs) work, and the potential benefits of using MFCs on tribal reservations to convert waste water to energy as a means to sustainably generate electricity. There have been no known studies conducted on tribal lands that would be able to add to the estimated percentage of all renewable energy resources identified. Not only does MFC technology provide a compelling, innovative solution, it could also address better management of wastewater, using it as a form of energy generation. Using wastewater for clean energy generation could provide a viable addition to community infrastructure systems improvements.

  18. Performance of denitrifying microbial fuel cell with biocathode over nitrite

    Zhao eHuimin

    2016-03-01

    Full Text Available Microbial fuel cell (MFC with nitrite as an electron acceptor in cathode provided a new technology for nitrogen removal and electricity production simultaneously. The influences of influent nitrite concentration and external resistance on the performance of denitrifying MFC were investigated. The optimal effectiveness were obtained with the maximum total nitrogen (TN removal rate of 54.80±0.01 g m-3 d-1. It would be rather desirable for the TN removal than electricity generation at lower external resistance. Denaturing gradient gel electrophoresis suggested that Proteobacteria was the predominant phylum, accounting for 35.72%. Thiobacillus and Afipia might benefit to nitrite removal. The presence of nitrifying Devosia indicated that nitrite was oxidized to nitrate via a biochemical mechanism in the cathode. Ignavibacterium and Anaerolineaceae was found in the cathode as a heterotrophic bacterium with sodium acetate as substrate, which illustrated that sodium acetate in anode was likely permeated through proton exchange membrane to the cathode .

  19. Tofu wastewater treatment by sediment microbial fuel cells

    Rinaldi, W.; Abubakar; Rahmi, R. F.; Silmina

    2018-03-01

    This research aimed to measure power density generated by sediment microbial fuel cells (SMFCs) by varying anode position and wastewater concentration. Anode position was varied at 2 cm and 4 cm under the surface of sediment, while wastewater concentration varied into 25%, 50%, 75% and 100%. The electrodes employed was stainless steel mesh, while the organic subtrate source was taken from wastewater of soybean washing and boiling process. The sediment was taken from the Lamnyong River around the outlet of tofu industry wastewater. SMFCs was run until the power density was relatively small. The produced electricity represented in power density. The results of this research showed that power density was decreased over time. Generated power density by varying 2 cm and 4 cm position of anode under the sediment surface was not significantly different, while the lowest wastewater concentration, 25%, gave the highest power density.

  20. Scaling up microbial fuel cells and other bioelectrochemical systems

    Logan, Bruce E.

    2009-01-01

    Scientific research has advanced on different microbial fuel cell (MFC) technologies in the laboratory at an amazing pace, with power densities having reached over 1 kW/m3 (reactor volume) and to 6.9 W/m2 (anode area) under optimal conditions. The main challenge is to bring these technologies out of the laboratory and engineer practical systems for bioenergy production at larger scales. Recent advances in new types of electrodes, a better understanding of the impact of membranes and separators on performance of these systems, and results from several new pilot-scale tests are all good indicators that commercialization of the technology could be possible within a few years. Some of the newest advances and future challenges are reviewed here with respect to practical applications of these MFCs for renewable energy production and other applications. © 2009 Springer-Verlag.

  1. Metabolism

    ... lin), which signals cells to increase their anabolic activities. Metabolism is a complicated chemical process, so it's not ... how those enzymes or hormones work. When the metabolism of body chemicals is ... Hyperthyroidism (pronounced: hi-per-THIGH-roy-dih-zum). Hyperthyroidism ...

  2. Effect of Bioprocessing on the In Vitro Colonic Microbial Metabolism of Phenolic Acids from Rye Bran Fortified Breads

    Koistinen, Ville M; Nordlund, Emilia; Katina, Kati

    2017-01-01

    in an in vitro colon model, the metabolites were analyzed using two different methods applying mass spectrometry. While phenolic acids were released more extensively from the bioprocessed bran bread and ferulic acid had consistently higher concentrations in the bread type during fermentation, there were only......Cereal bran is an important source of dietary fiber and bioactive compounds, such as phenolic acids. We aimed to study the phenolic acid metabolism of native and bioprocessed rye bran fortified refined wheat bread and to elucidate the microbial metabolic route of phenolic acids. After incubation...

  3. Stem cell metabolism in tissue development and aging

    Shyh-Chang, Ng; Daley, George Q.; Cantley, Lewis C.

    2013-01-01

    Recent advances in metabolomics and computational analysis have deepened our appreciation for the role of specific metabolic pathways in dictating cell fate. Once thought to be a mere consequence of the state of a cell, metabolism is now known to play a pivotal role in dictating whether a cell proliferates, differentiates or remains quiescent. Here, we review recent studies of metabolism in stem cells that have revealed a shift in the balance between glycolysis, mitochondrial oxidative phosphorylation and oxidative stress during the maturation of adult stem cells, and during the reprogramming of somatic cells to pluripotency. These insights promise to inform strategies for the directed differentiation of stem cells and to offer the potential for novel metabolic or pharmacological therapies to enhance regeneration and the treatment of degenerative disease. PMID:23715547

  4. Microbial metabolism alters pore water chemistry and increases consolidation of oil sands tailings.

    Arkell, Nicholas; Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

    2015-01-01

    Tailings produced during bitumen extraction from surface-mined oil sands ores (tar sands) comprise an aqueous suspension of clay particles that remain dispersed for decades in tailings ponds. Slow consolidation of the clays hinders water recovery for reuse and retards volume reduction, thereby increasing the environmental footprint of tailings ponds. We investigated mechanisms of tailings consolidation and revealed that indigenous anaerobic microorganisms altered porewater chemistry by producing CO and CH during metabolism of acetate added as a labile carbon amendment. Entrapped biogenic CO decreased tailings pH, thereby increasing calcium (Ca) and magnesium (Mg) cations and bicarbonate (HCO) concentrations in the porewater through dissolution of carbonate minerals. Soluble ions increased the porewater ionic strength, which, with higher exchangeable Ca and Mg, decreased the diffuse double layer of clays and increased consolidation of tailings compared with unamended tailings in which little microbial activity was observed. These results are relevant to effective tailings pond management strategies. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  5. 2004 Molecular Basis of Microbial One-Carbon Metabolism Gordon Conference - August 1-6, 2004

    Joseph A. Krzycki

    2005-09-15

    The Gordon Research Conference (GRC) on 2004 Molecular Basis of Microbial One-Carbon Metabolism Gordon Conference - August 1-6, 2004 was held at Mount Holyoke College, South Hadley, MA from August 1-6, 2004. The Conference was well-attended with 117 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, 'free time' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.

  6. Genetic and metabolic engineering for microbial production of poly-γ-glutamic acid.

    Cao, Mingfeng; Feng, Jun; Sirisansaneeyakul, Sarote; Song, Cunjiang; Chisti, Yusuf

    2018-05-28

    Poly-γ-glutamic acid (γ-PGA) is a natural biopolymer of glutamic acid. The repeating units of γ-PGA may be derived exclusively from d-glutamic acid, or l-glutamic acid, or both. The monomer units are linked by amide bonds between the α-amino group and the γ-carboxylic acid group. γ-PGA is biodegradable, edible and water-soluble. It has numerous existing and emerging applications in processing of foods, medicines and cosmetics. This review focuses on microbial production of γ-PGA via genetically and metabolically engineered recombinant bacteria. Strategies for improving production of γ-PGA include modification of its biosynthesis pathway, enhancing the production of its precursor (glutamic acid), and preventing loss of the precursor to competing byproducts. These and other strategies are discussed. Heterologous synthesis of γ-PGA in industrial bacterial hosts that do not naturally produce γ-PGA is discussed. Emerging trends and the challenges affecting the production of γ-PGA are reviewed. Copyright © 2018. Published by Elsevier Inc.

  7. Diversity, metabolism and microbial ecology of butyrate-producing bacteria from the human large intestine.

    Louis, Petra; Flint, Harry J

    2009-05-01

    Butyrate-producing bacteria play a key role in colonic health in humans. This review provides an overview of the current knowledge of the diversity, metabolism and microbial ecology of this functionally important group of bacteria. Human colonic butyrate producers are Gram-positive firmicutes, but are phylogenetically diverse, with the two most abundant groups related to Eubacterium rectale/Roseburia spp. and to Faecalibacterium prausnitzii. Five different arrangements have been identified for the genes of the central pathway involved in butyrate synthesis, while in most cases butyryl-CoA : acetate CoA-transferase, rather than butyrate kinase, appears to perform the final step in butyrate synthesis. Mechanisms have been proposed recently in non-gut Clostridium spp. whereby butyrate synthesis can result in energy generation via both substrate-level phosphorylation and proton gradients. Here we suggest that these mechanisms also apply to the majority of butyrate producers from the human colon. The roles of these bacteria in the gut community and their influence on health are now being uncovered, taking advantage of the availability of cultured isolates and molecular methodologies. Populations of F. prausnitzii are reported to be decreased in Crohn's disease, for example, while populations of Roseburia relatives appear to be particularly sensitive to the diet composition in human volunteer studies.

  8. Elevated CO2 shifts the functional structure and metabolic potentials of soil microbial communities in a C4 agroecosystem.

    Xiong, Jinbo; He, Zhili; Shi, Shengjing; Kent, Angela; Deng, Ye; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong

    2015-03-20

    Atmospheric CO2 concentration is continuously increasing, and previous studies have shown that elevated CO2 (eCO2) significantly impacts C3 plants and their soil microbial communities. However, little is known about effects of eCO2 on the compositional and functional structure, and metabolic potential of soil microbial communities under C4 plants. Here we showed that a C4 maize agroecosystem exposed to eCO2 for eight years shifted the functional and phylogenetic structure of soil microbial communities at both soil depths (0-5 cm and 5-15 cm) using EcoPlate and functional gene array (GeoChip 3.0) analyses. The abundances of key genes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were significantly stimulated under eCO2 at both soil depths, although some differences in carbon utilization patterns were observed between the two soil depths. Consistently, CO2 was found to be the dominant factor explaining 11.9% of the structural variation of functional genes, while depth and the interaction of depth and CO2 explained 5.2% and 3.8%, respectively. This study implies that eCO2 has profound effects on the functional structure and metabolic potential/activity of soil microbial communities associated with C4 plants, possibly leading to changes in ecosystem functioning and feedbacks to global change in C4 agroecosystems.

  9. Metabolic Plasticity of Stem Cells and Macrophages in Cancer

    Jelena Krstic

    2017-08-01

    Full Text Available In addition to providing essential molecules for the overall function of cells, metabolism plays an important role in cell fate and can be affected by microenvironmental stimuli as well as cellular interactions. As a specific niche, tumor microenvironment (TME, consisting of different cell types including stromal/stem cells and immune cells, is characterized by distinct metabolic properties. This review will be focused on the metabolic plasticity of mesenchymal stromal/stem cells (MSC and macrophages in TME, as well as on how the metabolic state of cancer stem cells (CSC, as key drivers of oncogenesis, affects their generation and persistence. Namely, heterogenic metabolic phenotypes of these cell populations, which include various levels of dependence on glycolysis or oxidative phosphorylation are closely linked to their complex roles in cancer progression. Besides well-known extrinsic factors, such as cytokines and growth factors, the differentiation and activation states of CSC, MSC, and macrophages are coordinated by metabolic reprogramming in TME. The significance of mutual metabolic interaction between tumor stroma and cancer cells in the immune evasion and persistence of CSC is currently under investigation.

  10. Microbial fuel cells for clogging assessment in constructed wetlands.

    Corbella, Clara; García, Joan; Puigagut, Jaume

    2016-11-01

    Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20kgTS·m(-3)CW·year(-1) at the beginning of the study period up to ca. 250kgTS·m(-3)CW·year(-1) at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2years (ca. 0.5kgTS·m(-3)CW) to ca. 5years (ca. 10kgTS·m(-3)CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5years of clogging (ca. 10kgTS·m(-3)CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. Copyright © 2016. Published by Elsevier B.V.

  11. A New Method for Water Desalination Using Microbial Desalination Cells

    Cao, Xiaoxin

    2009-09-15

    Current water desalination techniques are energy intensive and some use membranes operated at high pressures. It is shownhere that water desalination can be accomplished without electrical energy input or high water pressure by using a source of organic matter as the fuel to desalinate water. A microbial fuel cell was modified by placing two membranes between the anode and cathode, creating a middle chamber for water desalination between the membranes. An anion exchange membrane was placed adjacent to the anode, and a cation exchange membrane was positioned next to the cathode. When current was produced by bacteria on the anode, ionic species in the middle chamber were transferred into the two electrode chambers, desalinating the water in the middle chamber. Proof-of-concept experiments for this approach, using what we call a microbial desalination cell (MDC), was demonstrated using water at different initial salt concentrations (5, 20, and 35 g/L) with acetate used as the substrate for the bacteria. The MDC produced a maximum of 2 W/m2 (31 W/m3) while at the same time removing about 90% of the salt in a single desalination cycle. As the salt was removed from the middle chamber the ohmic resistance of the MDC (measured using electrochemical impedance spectroscopy) increased from 25 Ω to 970 Ω at the end of the cycle. This increased resistance was reflected by a continuous decrease in the voltage produced over the cycle. These results demonstrate for the first time the possibility for a new method for water desalination and power production that uses only a source of biodegradable organic matter and bacteria. © 2009 American Chemical Society.

  12. Microbial metagenomes from three aquifers in the Fennoscandian shield terrestrial deep biosphere reveal metabolic partitioning among populations.

    Wu, Xiaofen; Holmfeldt, Karin; Hubalek, Valerie; Lundin, Daniel; Åström, Mats; Bertilsson, Stefan; Dopson, Mark

    2016-05-01

    Microorganisms in the terrestrial deep biosphere host up to 20% of the earth's biomass and are suggested to be sustained by the gases hydrogen and carbon dioxide. A metagenome analysis of three deep subsurface water types of contrasting age (from 86% coverage. The populations were dominated by Proteobacteria, Candidate divisions, unclassified archaea and unclassified bacteria. The estimated genome sizes of the biosphere. The data were finally used to create a combined metabolic model of the deep terrestrial biosphere microbial community.

  13. A monetary comparison of energy recovered from microbial fuel cells and microbial electrolysis cells fed winery or domestic wastewaters

    Cusick, Roland D.; Kiely, Patrick D.; Logan, Bruce E. [Department of Civil and Environmental Engineering, H2E Center, Penn State University, University Park, PA 16802 (United States)

    2010-09-15

    Microbial fuel (MFCs) and electrolysis cells (MECs) can be used to recover energy directly as electricity or hydrogen from organic matter. Organic removal efficiencies and values of the different energy products were compared for MFCs and MECs fed winery or domestic wastewater. TCOD removal (%) and energy recoveries (kWh/kg-COD) were higher for MFCs than MECs with both wastewaters. At a cost of 4.51/kg-H{sub 2} for winery wastewater and 3.01/kg-H{sub 2} for domestic wastewater, the hydrogen produced using MECs cost less than the estimated merchant value of hydrogen (6/kg-H{sub 2}). 16S rRNA clone libraries indicated the predominance of Geobacter species in anodic microbial communities in MECs for both wastewaters, suggesting low current densities were the result of substrate limitations. The results of this study show that energy recovery and organic removal from wastewater are more effective with MFCs than MECs, but that hydrogen production from wastewater fed MECs can be cost effective. (author)

  14. Inhibition of fatty acid metabolism reduces human myeloma cells proliferation.

    José Manuel Tirado-Vélez

    Full Text Available Multiple myeloma is a haematological malignancy characterized by the clonal proliferation of plasma cells. It has been proposed that targeting cancer cell metabolism would provide a new selective anticancer therapeutic strategy. In this work, we tested the hypothesis that inhibition of β-oxidation and de novo fatty acid synthesis would reduce cell proliferation in human myeloma cells. We evaluated the effect of etomoxir and orlistat on fatty acid metabolism, glucose metabolism, cell cycle distribution, proliferation, cell death and expression of G1/S phase regulatory proteins in myeloma cells. Etomoxir and orlistat inhibited β-oxidation and de novo fatty acid synthesis respectively in myeloma cells, without altering significantly glucose metabolism. These effects were associated with reduced cell viability and cell cycle arrest in G0/G1. Specifically, etomoxir and orlistat reduced by 40-70% myeloma cells proliferation. The combination of etomoxir and orlistat resulted in an additive inhibitory effect on cell proliferation. Orlistat induced apoptosis and sensitized RPMI-8226 cells to apoptosis induction by bortezomib, whereas apoptosis was not altered by etomoxir. Finally, the inhibitory effect of both drugs on cell proliferation was associated with reduced p21 protein levels and phosphorylation levels of retinoblastoma protein. In conclusion, inhibition of fatty acid metabolism represents a potential therapeutic approach to treat human multiple myeloma.

  15. Three-Dimensional Carbon Nanotube−Textile Anode for High-Performance Microbial Fuel Cells

    Xie, Xing; Hu, Liangbing; Pasta, Mauro; Wells, George F.; Kong, Desheng; Criddle, Craig S.; Cui, Yi

    2011-01-01

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater. © 2011 American Chemical Society.

  16. Three-Dimensional Carbon Nanotube−Textile Anode for High-Performance Microbial Fuel Cells

    Xie, Xing

    2011-01-12

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater. © 2011 American Chemical Society.

  17. Electricity generation and microbial community analysis of alcohol powered microbial fuel cells.

    Kim, Jung Rae; Jung, Sok Hee; Regan, John M; Logan, Bruce E

    2007-09-01

    Two different microbial fuel cell (MFC) configurations were investigated for electricity production from ethanol and methanol: a two-chambered, aqueous-cathode MFC; and a single-chamber direct-air cathode MFC. Electricity was generated in the two-chamber system at a maximum power density typical of this system (40+/-2 mW/m2) and a Coulombic efficiency (CE) ranging from 42% to 61% using ethanol. When bacteria were transferred into a single-chamber MFC known to produce higher power densities with different substrates, the maximum power density increased to 488+/-12 mW/m2 (CE = 10%) with ethanol. The voltage generated exhibited saturation kinetics as a function of ethanol concentration in the two-chambered MFC, with a half-saturation constant (Ks) of 4.86 mM. Methanol was also examined as a possible substrate, but it did not result in appreciable electricity generation. Analysis of the anode biofilm and suspension from a two-chamber MFC with ethanol using 16S rDNA-based techniques indicated that bacteria with sequences similar to Proteobacterium Core-1 (33.3% of clone library sequences), Azoarcus sp. (17.4%), and Desulfuromonas sp. M76 (15.9%) were significant members of the anode chamber community. These results indicate that ethanol can be used for sustained electricity generation at room temperature using bacteria on the anode in a MFC.

  18. Gut Microbial Metabolism of Polyphenols from Black Tea and Red Wine/Grape Juice Is Source-Specific and Colon-Region Dependent

    Dorsten, van F.A.; Peters, S.; Gross, G.; Gomez-Roldan, V.; Klinkenberg, M.; Vos, de Ric; Vaughan, E.E.; Duynhoven, van J.P.M.; Possemiers, S.; Wiele, van der T.; Jacobs, D.M.

    2012-01-01

    The colonic microbial degradation of a polyphenol-rich black tea extract (BTE) and red wine/grape juice extract (RWGE) was compared in a five-stage in vitro gastrointestinal model (TWINSHIME). Microbial metabolism of BTE and RWGE polyphenols in the TWINSHIME was studied subsequently in single- and

  19. Microbial communities from different subsystems in biological heap leaching system play different roles in iron and sulfur metabolisms.

    Xiao, Yunhua; Liu, Xueduan; Ma, Liyuan; Liang, Yili; Niu, Jiaojiao; Gu, Yabing; Zhang, Xian; Hao, Xiaodong; Dong, Weiling; She, Siyuan; Yin, Huaqun

    2016-08-01

    The microbial communities are important for minerals decomposition in biological heap leaching system. However, the differentiation and relationship of composition and function of microbial communities between leaching heap (LH) and leaching solution (LS) are still unclear. In this study, 16S rRNA gene sequencing was used to assess the microbial communities from the two subsystems in ZiJinShan copper mine (Fujian province, China). Results of PCoA and dissimilarity test showed that microbial communities in LH samples were significantly different from those in LS samples. The dominant genera of LH was Acidithiobacillus (57.2 ∼ 87.9 %), while Leptospirillum (48.6 ∼ 73.7 %) was predominant in LS. Environmental parameters (especially pH) were the major factors to influence the composition and structure of microbial community by analysis of Mantel tests. Results of functional test showed that microbial communities in LH utilized sodium thiosulfate more quickly and utilized ferrous sulfate more slowly than those in LS, which further indicated that the most sulfur-oxidizing processes of bioleaching took place in LH and the most iron-oxidizing processes were in LS. Further study found that microbial communities in LH had stronger pyrite leaching ability, and iron extraction efficiency was significantly positively correlated with Acidithiobacillus (dominated in LH), which suggested that higher abundance ratio of sulfur-oxidizing microbes might in favor of minerals decomposition. Finally, a conceptual model was designed through the above results to better exhibit the sulfur and iron metabolism in bioleaching systems.

  20. Metabolic engineering of Saccharomyces cerevisiae: a key cell factory platform for future biorefineries.

    Hong, Kuk-Ki; Nielsen, Jens

    2012-08-01

    Metabolic engineering is the enabling science of development of efficient cell factories for the production of fuels, chemicals, pharmaceuticals, and food ingredients through microbial fermentations. The yeast Saccharomyces cerevisiae is a key cell factory already used for the production of a wide range of industrial products, and here we review ongoing work, particularly in industry, on using this organism for the production of butanol, which can be used as biofuel, and isoprenoids, which can find a wide range of applications including as pharmaceuticals and as biodiesel. We also look into how engineering of yeast can lead to improved uptake of sugars that are present in biomass hydrolyzates, and hereby allow for utilization of biomass as feedstock in the production of fuels and chemicals employing S. cerevisiae. Finally, we discuss the perspectives of how technologies from systems biology and synthetic biology can be used to advance metabolic engineering of yeast.

  1. INO80 Chromatin Remodeling Coordinates Metabolic Homeostasis with Cell Division

    Graeme J. Gowans

    2018-01-01

    Full Text Available Adaptive survival requires the coordination of nutrient availability with expenditure of cellular resources. For example, in nutrient-limited environments, 50% of all S. cerevisiae genes synchronize and exhibit periodic bursts of expression in coordination with respiration and cell division in the yeast metabolic cycle (YMC. Despite the importance of metabolic and proliferative synchrony, the majority of YMC regulators are currently unknown. Here, we demonstrate that the INO80 chromatin-remodeling complex is required to coordinate respiration and cell division with periodic gene expression. Specifically, INO80 mutants have severe defects in oxygen consumption and promiscuous cell division that is no longer coupled with metabolic status. In mutant cells, chromatin accessibility of periodic genes, including TORC1-responsive genes, is relatively static, concomitant with severely attenuated gene expression. Collectively, these results reveal that the INO80 complex mediates metabolic signaling to chromatin to restrict proliferation to metabolically optimal states.

  2. Colonization Habitat Controls Biomass, Composition, and Metabolic Activity of Attached Microbial Communities in the Columbia River Hyporheic Corridor

    Stern, Noah; Ginder-Vogel, Matthew; Stegen, James C.; Arntzen, Evan; Kennedy, David W.; Larget, Bret R.; Roden, Eric E.; Kostka, Joel E.

    2017-06-09

    Hydrologic exchange plays a critical role in biogeochemical cycling within the hyporheic zone (the interface between river water and groundwater) of riverine ecosystems. Such exchange may set limits on the rates of microbial metabolism and impose deterministic selection on microbial communities that adapt to dynamically changing dissolved organic carbon (DOC) sources. This study examined the response of attached microbial communities (in situcolonized sand packs) from groundwater, hyporheic, and riverbed habitats within the Columbia River hyporheic corridor to “cross-feeding” with either groundwater, river water, or DOC-free artificial fluids. Our working hypothesis was that deterministic selection duringin situcolonization would dictate the response to cross-feeding, with communities displaying maximal biomass and respiration when supplied with their native fluid source. In contrast to expectations, the major observation was that the riverbed colonized sand had much higher biomass and respiratory activity, as well as a distinct community structure, compared with those of the hyporheic and groundwater colonized sands. 16S rRNA gene amplicon sequencing revealed a much higher proportion of certain heterotrophic taxa as well as significant numbers of eukaryotic algal chloroplasts in the riverbed colonized sand. Significant quantities of DOC were released from riverbed sediment and colonized sand, and separate experiments showed that the released DOC stimulated respiration in the groundwater and piezometer colonized sand. These results suggest that the accumulation and degradation of labile particulate organic carbon (POC) within the riverbed are likely to release DOC, which may enter the hyporheic corridor during hydrologic exchange, thereby stimulating microbial activity and imposing deterministic selective pressure on the microbial community composition.

    IMPORTANCEThe influence of river water

  3. Electricity generation from tetrathionate in microbial fuel cells by acidophiles

    Sulonen, Mira L.K.; Kokko, Marika E.; Lakaniemi, Aino-Maija; Puhakka, Jaakko A.

    2015-01-01

    Highlights: • Electricity can be generated from tetrathionate in MFCs at pH below 2.5. • Tetrathionate disproportionated to sulfate and elemental sulfur. • Biohydrometallurgical process waters contained electrochemically active bacteria. • Acidithiobacillus spp. and Ferroplasma spp. were identified from the MFCs. - Abstract: Inorganic sulfur compounds, such as tetrathionate, are often present in mining process and waste waters. The biodegradation of tetrathionate was studied under acidic conditions in aerobic batch cultivations and in anaerobic anodes of two-chamber flow-through microbial fuel cells (MFCs). All four cultures originating from biohydrometallurgical process waters from multimetal ore heap bioleaching oxidized tetrathionate aerobically at pH below 3 with sulfate as the main soluble metabolite. In addition, all cultures generated electricity from tetrathionate in MFCs at pH below 2.5 with ferric iron as the terminal cathodic electron acceptor. The maximum current and power densities during MFC operation and in the performance analysis were 79.6 mA m −2 and 13.9 mW m −2 and 433 mA m −2 and 17.6 mW m −2 , respectively. However, the low coulombic efficiency (below 5%) indicates that most of the electrons were directed to other processes, such as aerobic oxidation of tetrathionate and unmeasured intermediates. The microbial community analysis revealed that the dominant species both in the anolyte and on the anode electrode surface of the MFCs were Acidithiobacillus spp. and Ferroplasma spp. This study provides a proof of concept that tetrathionate serves as electron donor for biological electricity production in the pH range of 1.2–2.5

  4. Convergent development of anodic bacterial communities in microbial fuel cells.

    Yates, Matthew D

    2012-05-10

    Microbial fuel cells (MFCs) are often inoculated from a single wastewater source. The extent that the inoculum affects community development or power production is unknown. The stable anodic microbial communities in MFCs were examined using three inocula: a wastewater treatment plant sample known to produce consistent power densities, a second wastewater treatment plant sample, and an anaerobic bog sediment. The bog-inoculated MFCs initially produced higher power densities than the wastewater-inoculated MFCs, but after 20 cycles all MFCs on average converged to similar voltages (470±20 mV) and maximum power densities (590±170 mW m(-2)). The power output from replicate bog-inoculated MFCs was not significantly different, but one wastewater-inoculated MFC (UAJA3 (UAJA, University Area Joint Authority Wastewater Treatment Plant)) produced substantially less power. Denaturing gradient gel electrophoresis profiling showed a stable exoelectrogenic biofilm community in all samples after 11 cycles. After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%). While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses. These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

  5. Electricity generation from tetrathionate in microbial fuel cells by acidophiles

    Sulonen, Mira L.K., E-mail: mira.sulonen@tut.fi; Kokko, Marika E.; Lakaniemi, Aino-Maija; Puhakka, Jaakko A.

    2015-03-02

    Highlights: • Electricity can be generated from tetrathionate in MFCs at pH below 2.5. • Tetrathionate disproportionated to sulfate and elemental sulfur. • Biohydrometallurgical process waters contained electrochemically active bacteria. • Acidithiobacillus spp. and Ferroplasma spp. were identified from the MFCs. - Abstract: Inorganic sulfur compounds, such as tetrathionate, are often present in mining process and waste waters. The biodegradation of tetrathionate was studied under acidic conditions in aerobic batch cultivations and in anaerobic anodes of two-chamber flow-through microbial fuel cells (MFCs). All four cultures originating from biohydrometallurgical process waters from multimetal ore heap bioleaching oxidized tetrathionate aerobically at pH below 3 with sulfate as the main soluble metabolite. In addition, all cultures generated electricity from tetrathionate in MFCs at pH below 2.5 with ferric iron as the terminal cathodic electron acceptor. The maximum current and power densities during MFC operation and in the performance analysis were 79.6 mA m{sup −2} and 13.9 mW m{sup −2} and 433 mA m{sup −2} and 17.6 mW m{sup −2}, respectively. However, the low coulombic efficiency (below 5%) indicates that most of the electrons were directed to other processes, such as aerobic oxidation of tetrathionate and unmeasured intermediates. The microbial community analysis revealed that the dominant species both in the anolyte and on the anode electrode surface of the MFCs were Acidithiobacillus spp. and Ferroplasma spp. This study provides a proof of concept that tetrathionate serves as electron donor for biological electricity production in the pH range of 1.2–2.5.

  6. Genome-Enabled Modeling of Biogeochemical Processes Predicts Metabolic Dependencies that Connect the Relative Fitness of Microbial Functional Guilds

    Brodie, E.; King, E.; Molins, S.; Karaoz, U.; Steefel, C. I.; Banfield, J. F.; Beller, H. R.; Anantharaman, K.; Ligocki, T. J.; Trebotich, D.

    2015-12-01

    Pore-scale processes mediated by microorganisms underlie a range of critical ecosystem services, regulating carbon stability, nutrient flux, and the purification of water. Advances in cultivation-independent approaches now provide us with the ability to reconstruct thousands of genomes from microbial populations from which functional roles may be assigned. With this capability to reveal microbial metabolic potential, the next step is to put these microbes back where they belong to interact with their natural environment, i.e. the pore scale. At this scale, microorganisms communicate, cooperate and compete across their fitness landscapes with communities emerging that feedback on the physical and chemical properties of their environment, ultimately altering the fitness landscape and selecting for new microbial communities with new properties and so on. We have developed a trait-based model of microbial activity that simulates coupled functional guilds that are parameterized with unique combinations of traits that govern fitness under dynamic conditions. Using a reactive transport framework, we simulate the thermodynamics of coupled electron donor-acceptor reactions to predict energy available for cellular maintenance, respiration, biomass development, and enzyme production. From metagenomics, we directly estimate some trait values related to growth and identify the linkage of key traits associated with respiration and fermentation, macromolecule depolymerizing enzymes, and other key functions such as nitrogen fixation. Our simulations were carried out to explore abiotic controls on community emergence such as seasonally fluctuating water table regimes across floodplain organic matter hotspots. Simulations and metagenomic/metatranscriptomic observations highlighted the many dependencies connecting the relative fitness of functional guilds and the importance of chemolithoautotrophic lifestyles. Using an X-Ray microCT-derived soil microaggregate physical model combined

  7. Energy sustainability of Microbial Fuel Cell (MFC): A case study

    Tommasi, Tonia; Lombardelli, Giorgia

    2017-07-01

    Energy sustainability analysis and durability of Microbial Fuel Cells (MFCs) as energy source are necessary in order to move from the laboratory scale to full-scale application. This paper focus on these two aspects by considering the energy performances of an original experimental test with MFC conducted for six months under an external load of 1000 Ω. Energy sustainability is quantified using Energy Payback Time, the time necessary to produce the energy already spent to construct the MFC device. The results of experiment reveal that the energy sustainability of this specific MFC is never reached due to energy expenditure (i.e. for pumping) and to the low amount of energy produced. Hence, different MFC materials and architectures were analysed to find guidelines for future MFC development. Among these, only sedimentary fuel cells (Benthic MFCs) seem sustainable from an energetic point of view, with a minimum duration of 2.7 years. An energy balance approach highlights the importance of energy calculation. However, this is very often not taken into account in literature. This study outlines promising methodology for the design of an alternative layout of energy sustainable MFC and wastewater management systems.

  8. Microbial fuel cells with highly active aerobic biocathodes

    Milner, Edward M.; Popescu, Dorin; Curtis, Tom; Head, Ian M.; Scott, Keith; Yu, Eileen H.

    2016-08-01

    Microbial fuel cells (MFCs), which convert organic waste to electricity, could be used to make the wastewater infrastructure more energy efficient and sustainable. However, platinum and other non-platinum chemical catalysts used for the oxygen reduction reaction (ORR) at the cathode of MFCs are unsustainable due to their high cost and long-term degradation. Aerobic biocathodes, which use microorganisms as the biocatalysts for cathode ORR, are a good alternative to chemical catalysts. In the current work, high-performing aerobic biocathodes with an onset potential for the ORR of +0.4 V vs. Ag/AgCl were enriched from activated sludge in electrochemical half-cells poised at -0.1 and + 0.2 V vs. Ag/AgCl. Gammaproteobacteria, distantly related to any known cultivated gammaproteobacterial lineage, were identified as dominant in these working electrode biofilms (23.3-44.3% of reads in 16S rRNA gene Ion Torrent libraries), and were in very low abundance in non-polarised control working electrode biofilms (0.5-0.7%). These Gammaproteobacteria were therefore most likely responsible for the high activity of biologically catalysed ORR. In MFC tests, a high-performing aerobic biocathode increased peak power 9-fold from 7 to 62 μW cm-2 in comparison to an unmodified carbon cathode, which was similar to peak power with a platinum-doped cathode at 70 μW cm-2.

  9. Impact of anti-acidification microbial consortium on carbohydrate metabolism of key microbes during food waste composting.

    Song, Caihong; Li, Mingxiao; Qi, Hui; Zhang, Yali; Liu, Dongming; Xia, Xunfeng; Pan, Hongwei; Xi, Beidou

    2018-07-01

    This study investigated the effect of anti-acidification microbial consortium (AAMC), which act synergistically for rapid bioconversion of organic acids on carbohydrate metabolism of key microbes in the course of food waste (FW) composting by metaproteomics. AAMC was inoculated to the composting mass and compared with treatment with alkaline compounds and the control without any amendment. Inoculating AAMC could effectively accelerate carbohydrate degradation process and improve composting efficiency. Carbohydrate metabolic network profiles showed the inoculation with AAMC could increase significantly the types of enzymes catalysing the degradation of lignin, cellulose and hemicellulose. Furthermore, AAMC inoculum could increase not only diversities of microbes producing key enzymes in metabolism pathways of acetic and propionic acids, but also the amounts of these key enzymes. The increase of diversities of microbes could disperse the pressure from acidic adversity on microorganisms which were capable to degrade acetic and propionic acids. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Improved performance of microbial fuel cells enriched with natural microbial inocula and treated by electrical current

    Lin, Hongjian; Wu, Xiao; Miller, Curtis; Zhu, Jun

    2013-01-01

    Microbial fuel cells (MFCs) are increasingly attracting attention as a sustainable technology as they convert chemical energy in organic wastes to electricity. In this study, the effects of different inoculum sources (river sediment, activated sludge and anaerobic sludge) and electrical current stimulation were evaluated using single-chamber air-cathode MFCs as model reactors based on performance in enrichment process and electrochemical characteristics of the reactors. The result revealed the rapid anodic biofilm development and substrate utilization of the anaerobic sludge-inoculated MFC. It was also found that the river sediment-inoculated MFC achieved the highest power output of 195 μW, or 98 mW m −2 , due to better developed anodic biofilm confirmed by scanning electron microscopy. The current stimulation enhanced the anodic biofilm attachment over time, and therefore reduced the MFC internal resistance by 27%, increased the electrical capacitance by four folds, and improved the anodic biofilm resilience against substrate deprivation. For mature MFCs, a transient application of a negative voltage (−3 V) improved the cathode activity and maximum power output by 37%. This improvement was due to the bactericidal effect of the electrode potential higher than +1.5 V vs. SHE, demonstrating a substantial benefit of treating MFC cathode after long-term operation using suitable direct electrical current. -- Highlights: •Voltage stimulation (+2 V) during inoculation reduced MFC internal resistance and improved biofilm resilience. •Voltage stimulation increased biofilm electrical capacitance by 5-fold. •Negative voltage stimulation (−3 V) enhanced the maximum power output by 37%. •River sediment MFC obtained higher power due to better anodic biofilm coverage. •Anaerobic sludge quickly developed anodic biofilm for MFC and quickly utilized volatile fatty acids

  11. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    Logan, B.E.; Call, D.; Cheng, S.; Hamelers, H.V.M.; Sleutels, T.H.J.A.; Jeremiasse, A.W.; Rozendal, R.A.

    2008-01-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few

  12. Dysregulation of Iron Metabolism in Cholangiocarcinoma Stem-like Cells

    Raggi, Chiara; Gammella, Elena; Correnti, Margherita

    2017-01-01

    Cholangiocarcinoma (CCA) is a devastating liver tumour arising from malignant transformation of bile duct epithelial cells. Cancer stem cells (CSC) are a subset of tumour cells endowed with stem-like properties, which play a role in tumour initiation, recurrence and metastasis. In appropriate con...... compartment as a novel metabolic factor involved in CCA growth, may have implications for a better therapeutic approach....

  13. Vitamin K metabolism in Chinese Hamster Ovary cells

    Hoffman, H.S.

    1986-01-01

    Recent investigations suggest that vitamin K may have functions other than in blood coagulation and calcification. The present study was undertaken to investigate this hypothesis using cells in culture. Chinese Hamster Ovary (CHO) cells were chosen due to their active metabolism and growth and lack of similarity to liver and bone cells, in which vitamin K metabolism is well known. Cells were adapted to serum-free media, incubated in media containing the appropriate concentrations of vitamin K for specified times, scraped from plates, pelleted, extensively washed to remove adhering vitamin K, extracted with chloroform:methanol (2:1, v/v) and analyzed on C18 HPLC columns. Uptake of vitamin K by CHO cells follows saturation kinetics at vitamin K concentrations up to 25 μ M and is transported into cells at the rate of 10 pmol/min. 10 6 cells. After 24 hours, 3 H vitamin K is metabolized by CHO cells to several compounds, the major of which was isolated and identified as vitamin K epoxide. In 3 experiments, after 24 hours, the average cellular uptake of vitamin K was 8% with approximately half being metabolized to vitamin K epoxide. These results demonstrate that vitamin K is metabolized in cells with widely different functions and suggest a generalized function for vitamin K which has yet to be elucidated

  14. Does canine inflammatory bowel disease influence gut microbial profile and host metabolism?

    Xu, Jia; Verbrugghe, Adronie; Lourenço, Marta; Janssens, Geert P.J.; Liu, Daisy J.X.; Wiele, Van de Tom; Eeckhaut, Venessa; Immerseel, Van Filip; Maele, Van de Isabel; Niu, Yufeng; Bosch, Guido; Junius, Greet; Wuyts, Brigitte; Hesta, Myriam

    2016-01-01

    Background: Inflammatory bowel disease (IBD) refers to a diverse group of chronic gastrointestinal diseases, and gut microbial dysbiosis has been proposed as a modulating factor in its pathogenesis. Several studies have investigated the gut microbial ecology of dogs with IBD but it is yet unclear

  15. Metabolic rate determines haematopoietic stem cell self-renewal.

    Sastry, P S R K

    2004-01-01

    The number of haematopoietic stem cells (HSCs) per animal is conserved across species. This means the HSCs need to maintain hematopoiesis over a longer period in larger animals. This would result in the requirement of stem cell self-renewal. At present the three existing models are the stochastic model, instructive model and the third more recently proposed is the chiaro-scuro model. It is a well known allometric law that metabolic rate scales to the three quarter power. Larger animals have a lower metabolic rate, compared to smaller animals. Here it is being hypothesized that metabolic rate determines haematopoietic stem cell self-renewal. At lower metabolic rate the stem cells commit for self-renewal, where as at higher metabolic rate they become committed to different lineages. The present hypothesis can explain the salient features of the different models. Recent findings regarding stem cell self-renewal suggest an important role for Wnt proteins and their receptors known as frizzleds, which are an important component of cell signaling pathway. The role of cGMP in the Wnts action provides further justification for the present hypothesis as cGMP is intricately linked to metabolic rate. One can also explain the telomere homeostasis by the present hypothesis. One prediction of the present hypothesis is with reference to the limit of cell divisions known as Hayflick limit, here it is being suggested that this is the result of metabolic rate in laboratory conditions and there can be higher number of cell divisions in vivo if the metabolic rate is lower. Copyright 2004 Elsevier Ltd.

  16. Polymer coatings as separator layers for microbial fuel cell cathodes

    Watson, Valerie J.

    2011-03-01

    Membrane separators reduce oxygen flux from the cathode into the anolyte in microbial fuel cells (MFCs), but water accumulation and pH gradients between the separator and cathode reduces performance. Air cathodes were spray-coated (water-facing side) with anion exchange, cation exchange, and neutral polymer coatings of different thicknesses to incorporate the separator into the cathode. The anion exchange polymer coating resulted in greater power density (1167 ± 135 mW m-2) than a cation exchange coating (439 ± 2 mW m-2). This power output was similar to that produced by a Nafion-coated cathode (1114 ± 174 mW m-2), and slightly lower than the uncoated cathode (1384 ± 82 mW m-2). Thicker coatings reduced oxygen diffusion into the electrolyte and increased coulombic efficiency (CE = 56-64%) relative to an uncoated cathode (29 ± 8%), but decreased power production (255-574 mW m-2). Electrochemical characterization of the cathodes ex situ to the MFC showed that the cathodes with the lowest charge transfer resistance and the highest oxygen reduction activity produced the most power in MFC tests. The results on hydrophilic cathode separator layers revealed a trade off between power and CE. Cathodes coated with a thin coating of anion exchange polymer show promise for controlling oxygen transfer while minimally affecting power production. © 2010 Elsevier B.V. All rights reserved.

  17. Microbial fuel cell as a free-radical scavenging tool

    Koleva, Ralitza; Yemendzhiev, Hyusein; Nenov, Valentin

    2017-01-01

    Microbial fuel cells (MFCs) are known for their capability to directly convert organic substrates into electricity by the biochemical activity of specific microorganisms. Availability of a proper terminal electron acceptor is crucial for this process. Free radicals, with their one or more unpaired electrons, are extremely reducible and could be considered as electron acceptors in terms of cathodic processes in MFC. During this reduction, free radicals could be transformed in the same manner as they are transformed by antioxidants. The present study investigated this opportunity by utilization of 2,2-diphenyl-1-picrylhydrazyl (150 mmol/dm"3 methanol solution) as a free-radical molecule. During the studied process, over 90% radical neutralization was observed in less than 16 hours. The results obtained demonstrate for the first time the potential of MFC type bioelectrochemical systems to serve as a free-radical scavenging tool and to provide antioxidant and anti-radical activity. In this way, this study opens a completely new field of research and application of bio-electrochemical systems

  18. Microbial desalination cells for energy production and desalination

    Kim, Younggy

    2013-01-01

    Microbial desalination cells (MDCs) are a new, energy-sustainable method for using organic matter in wastewater as the energy source for desalination. The electric potential gradient created by exoelectrogenic bacteria desalinates water by driving ion transport through a series of ion-exchange membranes (IEMs). The specific MDC architecture and current conditions substantially affect the amount of wastewater needed to desalinate water. Other baseline conditions have varied among studies making comparisons of the effectiveness of different designs problematic. The extent of desalination is affected by water transport through IEMs by both osmosis and electroosmosis. Various methods have been used, such as electrolyte recirculation, to avoid low pH that can inhibit exoelectrogenic activity. The highest current density in an MDC to date is 8.4A/m2, which is lower than that produced in other bioelectrochemical systems. This implies that there is a room for substantial improvement in desalination rates and overall performance. We review here the state of the art in MDC design and performance, safety issues related to the use of MDCs with wastewater, and areas that need to be examined to achieve practical application of this new technology. © 2012 Elsevier B.V.

  19. Copper anode corrosion affects power generation in microbial fuel cells

    Zhu, Xiuping; Logan, Bruce E.

    2013-01-01

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  20. [Electricity generation from corn steepwater using microbial fuel cell technology].

    Lu, Na; Zhou, Shun-Gui; Zhang, Jin-Tao; Ni, Jin-Ren

    2009-02-15

    Corn steepwater containing 49,732.2 mg/L of chemical oxygen demand (COD) was used as fuel for a membrane electrode assembly microbial fuel cell (MEA-MFC), which could generate electricity and treat the wastewater at the same time. During a batch experiment of 94 days with a fixed 1,000 Omega external resistance, the maximum voltage output of 525.0 mV and power density of 169.6 mW/m2 were obtained after 17 days, corresponding to the current density, internal resistance and open voltage of 440.2 mA/m2, 350 Omega and 619.5 mV, respectively. However, data showed that the coulombic efficiency was only 1.6%, suggesting very limited COD was utilized for electricity generation. At the conclusion of the test, the removals of COD and ammonia-nitrogen were achieved 51.6% and 25.8%, respectively. This study demonstrates that corn steepwater can be used for power generation in MFC with simultaneous accomplishments of wastewater treatment, providing a novel approach for the safe disposal and recycle of corn steepwater.

  1. Copper anode corrosion affects power generation in microbial fuel cells

    Zhu, Xiuping

    2013-07-16

    Non-corrosive, carbon-based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m-2). Higher power was produced with microbes using SS (12 mW m-2) or carbon cloth (880 mW m-2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. © 2013 Society of Chemical Industry.

  2. Methanobacterium Dominates Biocathodic Archaeal Communities in Methanogenic Microbial Electrolysis Cells

    Siegert, Michael

    2015-07-06

    © 2015 American Chemical Society. Methane is the primary end product from cathodic current in microbial electrolysis cells (MECs) in the absence of methanogenic inhibitors, but little is known about the archaeal communities that develop in these systems. MECs containing cathodes made from different materials (carbon brushes, or plain graphite blocks or blocks coated with carbon black and platinum, stainless steel, nickel, ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide) were inoculated with anaerobic digester sludge and acclimated at a set potential of -600 mV (versus a standard hydrogen electrode). The archaeal communities on all cathodes, except those coated with platinum, were predominated by Methanobacterium (median 97% of archaea). Cathodes with platinum contained mainly archaea most similar to Methanobrevibacter. Neither of these methanogens were abundant (<0.1% of archaea) in the inoculum, and therefore their high abundance on the cathode resulted from selective enrichment. In contrast, bacterial communities on the cathode were more diverse, containing primarily δ-Proteobacteria (41% of bacteria). The lack of a consistent bacterial genus on the cathodes indicated that there was no similarly selective enrichment of bacteria on the cathode. These results suggest that the genus Methanobacterium was primarily responsible for methane production in MECs when cathodes lack efficient catalysts for hydrogen gas evolution. (Figure Presented).

  3. A novel microbial fuel cell sensor with biocathode sensing element.

    Jiang, Yong; Liang, Peng; Liu, Panpan; Wang, Donglin; Miao, Bo; Huang, Xia

    2017-08-15

    The traditional microbial fuel cell (MFC) sensor with bioanode as sensing element delivers limited sensitivity to toxicity monitoring, restricted application to only anaerobic and organic rich water body, and increased potential fault warning to the combined shock of organic matter/toxicity. In this study, the biocathode for oxygen reduction reaction was employed for the first time as the sensing element in MFC sensor for toxicity monitoring. The results shown that the sensitivity of MFC sensor with biocathode sensing element (7.4±2.0 to 67.5±4.0mA% -1 cm -2 ) was much greater than that showed by bioanode sensing element (3.4±1.5 to 5.5±0.7mA% -1 cm -2 ). The biocathode sensing element achieved the lowest detection limit reported to date using MFC sensor for formaldehyde detection (0.0005%), while the bioanode was more applicable for higher concentration (>0.0025%). There was a quicker response of biocathode sensing element with the increase of conductivity and dissolved oxygen (DO). The biocathode sensing element made the MFC sensor directly applied to clean water body monitoring, e.g., drinking water and reclaimed water, without the amending of background organic matter, and it also decreased the warning failure when challenged by a combined shock of organic matter/toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Carbon nanotube fiber mats for microbial fuel cell electrodes.

    Delord, Brigitte; Neri, Wilfrid; Bertaux, Karen; Derre, Alain; Ly, Isabelle; Mano, Nicolas; Poulin, Philippe

    2017-11-01

    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. This porosity allows an easy colonization by electroactive bacteria. In addition, the fibers display a nanostructuration that promotes excellent growth and adhesion of the bacteria at the surface of the electrodes. This unique combination of large scale porosity and nanostructuration allows the present electrodes to perform better than carbon reference. When used as anode in a bioelectrochemical reactor in presence of Geobacter sulfurreducens bacteria, the present electrodes show a maximal current density of about 7.5mA/cm 2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Models for Microbial Fuel Cells: A critical review

    Xia, Chengshuo; Zhang, Daxing; Pedrycz, Witold; Zhu, Yingmin; Guo, Yongxian

    2018-01-01

    Microbial fuel cells (MFCs) have been widely viewed as one of the most promising alternative sources of renewable energy. A recognition of needs of efficient development methods based on multidisciplinary research becomes crucial for the optimization of MFCs. Modeling of MFCs is an effective way for not only gaining a thorough understanding of the effects of operation conditions on the performance of power generation but also becomes of essential interest to the successful implementation of MFCs. The MFC models encompass the underlying reaction process and limiting factors of the MFC. The models come in various forms, such as the mathematical equations or the equivalent circuits. Different modeling focuses and approaches of the MFC have emerged. In this study, we present a state of the art of MFCs modeling; the past modeling methods are reviewed as well. Models and modeling methods are elaborated on based on the classification provided by Mechanism-based models and Application-based models. Mechanisms, advantages, drawbacks, and application fields of different models are illustrated as well. We exhibit a complete and comprehensive exposition of the different models for MFCs and offer further guidance to promote the performance of MFCs.

  6. Simultaneous electricity production and antibiotics removal by microbial fuel cells.

    Zhou, Ying; Zhu, Nengwu; Guo, Wenying; Wang, Yun; Huang, Xixian; Wu, Pingxiao; Dang, Zhi; Zhang, Xiaoping; Xian, Jinchan

    2018-04-07

    The removal of antibiotics is crucial for improvement of water quality in animal wastewater treatment. In this paper, the performance of microbial fuel cell (MFC) in terms of degradation of typical antibiotics was investigated. Electricity was successfully produced by using sludge supernatant mixtures and synthesized animal wastewater as inoculation in MFC. Results demonstrated that the stable voltage, the maximum power density and internal resistance of anaerobic self-electrolysis (ASE) -112 and ASE-116 without antibiotics addition were 0.574 V, 5.78 W m -3 and 28.06 Ω, and 0.565 V, 5.82 W m -3 and 29.38 Ω, respectively. Moreover, when adding aureomycin, sulfadimidine, roxithromycin and norfloxacin into the reactors, the performance of MFC was inhibited (0.51 V-0.41 V), while the output voltage was improved with the decreased concentration of antibiotics. However, the removal efficiency of ammonia nitrogen (NH 3 -N) and total phosphorus (TP) were both obviously enhanced. Simultaneously, LC-MS analysis showed that the removal efficiency of aureomycin, roxithromycin and norfloxacin were all 100% and the removal efficiency of sulfadimidine also reached 99.9%. These results indicated that antibiotics displayed significantly inhibitions for electricity performance but improved the quality of water simultaneously. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. The Dark Side of the Mushroom Spring Microbial Mat: Life in the Shadow of Chlorophototrophs. II. Metabolic Functions of Abundant Community Members Predicted from Metagenomic Analyses.

    Thiel, Vera; Hügler, Michael; Ward, David M; Bryant, Donald A

    2017-01-01

    Microbial mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin of Yellowstone National Park have been extensively characterized. Previous studies have focused on the chlorophototrophic organisms of the phyla Cyanobacteria and Chloroflexi . However, the diversity and metabolic functions of the other portion of the community in the microoxic/anoxic region of the mat are poorly understood. We recently described the diverse but extremely uneven microbial assemblage in the undermat of Mushroom Spring based on 16S rRNA amplicon sequences, which was dominated by Roseiflexus members, filamentous anoxygenic chlorophototrophs. In this study, we analyzed the orange-colored undermat portion of the community of Mushroom Spring mats in a genome-centric approach and discuss the metabolic potentials of the major members. Metagenome binning recovered partial genomes of all abundant community members, ranging in completeness from ~28 to 96%, and allowed affiliation of function with taxonomic identity even for representatives of novel and Candidate phyla. Less complete metagenomic bins correlated with high microdiversity. The undermat portion of the community was found to be a mixture of phototrophic and chemotrophic organisms, which use bicarbonate as well as organic carbon sources derived from different cell components and fermentation products. The presence of rhodopsin genes in many taxa strengthens the hypothesis that light energy is of major importance. Evidence for the usage of all four bacterial carbon fixation pathways was found in the metagenome. Nitrogen fixation appears to be limited to Synechococcus spp. in the upper mat layer and Thermodesulfovibrio sp. in the undermat, and nitrate/nitrite metabolism was limited. A closed sulfur cycle is indicated by biological sulfate reduction combined with the presence of genes for sulfide oxidation mainly in phototrophs. Finally, a variety of undermat microorganisms have genes for

  8. The Dark Side of the Mushroom Spring Microbial Mat: Life in the Shadow of Chlorophototrophs. II. Metabolic Functions of Abundant Community Members Predicted from Metagenomic Analyses

    Vera Thiel

    2017-06-01

    Full Text Available Microbial mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin of Yellowstone National Park have been extensively characterized. Previous studies have focused on the chlorophototrophic organisms of the phyla Cyanobacteria and Chloroflexi. However, the diversity and metabolic functions of the other portion of the community in the microoxic/anoxic region of the mat are poorly understood. We recently described the diverse but extremely uneven microbial assemblage in the undermat of Mushroom Spring based on 16S rRNA amplicon sequences, which was dominated by Roseiflexus members, filamentous anoxygenic chlorophototrophs. In this study, we analyzed the orange-colored undermat portion of the community of Mushroom Spring mats in a genome-centric approach and discuss the metabolic potentials of the major members. Metagenome binning recovered partial genomes of all abundant community members, ranging in completeness from ~28 to 96%, and allowed affiliation of function with taxonomic identity even for representatives of novel and Candidate phyla. Less complete metagenomic bins correlated with high microdiversity. The undermat portion of the community was found to be a mixture of phototrophic and chemotrophic organisms, which use bicarbonate as well as organic carbon sources derived from different cell components and fermentation products. The presence of rhodopsin genes in many taxa strengthens the hypothesis that light energy is of major importance. Evidence for the usage of all four bacterial carbon fixation pathways was found in the metagenome. Nitrogen fixation appears to be limited to Synechococcus spp. in the upper mat layer and Thermodesulfovibrio sp. in the undermat, and nitrate/nitrite metabolism was limited. A closed sulfur cycle is indicated by biological sulfate reduction combined with the presence of genes for sulfide oxidation mainly in phototrophs. Finally, a variety of undermat

  9. Metabolism during ECM Detachment: Achilles Heel of Cancer Cells?

    Mason, Joshua A; Hagel, Kimberly R; Hawk, Mark A; Schafer, Zachary T

    2017-07-01

    Integrin-mediated attachment to the extracellular matrix (ECM) is required to combat the induction of programmed cell death in a variety of distinct cell types. If cells fail to maintain proper ECM attachment, they become subject to elimination via an apoptotic cell death program known as anoikis. However, anoikis inhibition is not sufficient to promote the long-term survival of ECM-detached cells. Several recent studies have unveiled the profound (anoikis-independent) impact of cell metabolism on the viability of ECM-detached cells. Thus, we posit that, during metastatic dissemination (when cancer cells are exposed to periods of ECM detachment), cancer cells must alter their metabolism in a fashion that promotes survival and ultimately contributes to metastatic outgrowth. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Anaerobic 4-hydroxyproline utilization: Discovery of a new glycyl radical enzyme in the human gut microbiome uncovers a widespread microbial metabolic activity.

    Huang, Yolanda Y; Martínez-Del Campo, Ana; Balskus, Emily P

    2018-02-06

    The discovery of enzymes responsible for previously unappreciated microbial metabolic pathways furthers our understanding of host-microbe and microbe-microbe interactions. We recently identified and characterized a new gut microbial glycyl radical enzyme (GRE) responsible for anaerobic metabolism of trans-4-hydroxy-l-proline (Hyp). Hyp dehydratase (HypD) catalyzes the removal of water from Hyp to generate Δ 1 -pyrroline-5-carboxylate (P5C). This enzyme is encoded in the genomes of a diverse set of gut anaerobes and is prevalent and abundant in healthy human stool metagenomes. Here, we discuss the roles HypD may play in different microbial metabolic pathways as well as the potential implications of this activity for colonization resistance and pathogenesis within the human gut. Finally, we present evidence of anaerobic Hyp metabolism in sediments through enrichment culturing of Hyp-degrading bacteria, highlighting the wide distribution of this pathway in anoxic environments beyond the human gut.

  11. Controlling the occurrence of power overshoot by adapting microbial fuel cells to high anode potentials

    Zhu, Xiuping; Tokash, Justin C.; Hong, Yiying; Logan, Bruce E.

    2013-01-01

    Power density curves for microbial fuel cells (MFCs) often show power overshoot, resulting in inaccurate estimation of MFC performance at high current densities. The reasons for power overshoot are not well understood, but biofilm acclimation

  12. Energy harvesting from organic liquids in micro-sized microbial fuel cells

    Mink, J.E.; Qaisi, R.M.; Logan, B.E.; Hussain, Muhammad Mustafa

    2014-01-01

    Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using

  13. Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells

    Nam, Joo-Youn; Kim, Hyun-Woo; Lim, Kyeong-Ho; Shin, Hang-Sik; Logan, Bruce E.

    2010-01-01

    Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers

  14. Carbon nanotube-coated macroporous sponge for microbial fuel cell electrodes

    Xie, Xing; Ye, Meng; Hu, Liangbing; Liu, Nian; McDonough, James R.; Chen, Wei; Alshareef, Husam N.; Criddle, Craig S.; Cui, Yi

    2012-01-01

    The materials that are used to make electrodes and their internal structures significantly affect microbial fuel cell (MFC) performance. In this study, we describe a carbon nanotube (CNT)-sponge composite prepared by coating a sponge with CNTs

  15. Graphene–sponges as high-performance low-cost anodes for microbial fuel cells

    Xie, Xing; Yu, Guihua; Liu, Nian; Bao, Zhenan; Criddle, Craig S.; Cui, Yi

    2012-01-01

    A high-performance microbial fuel cell (MFC) anode was constructed from inexpensive materials. Key components were a graphene-sponge (G-S) composite and a stainless-steel (SS) current collector. Anode fabrication is simple, scalable

  16. Improving startup performance with carbon mesh anodes in separator electrode assembly microbial fuel cells

    Zhang, Fang; Xia, Xue; Luo, Yong; Sun, Dan; Call, Douglas F.; Logan, Bruce E.

    2013-01-01

    In a separator electrode assembly microbial fuel cell, oxygen crossover from the cathode inhibits current generation by exoelectrogenic bacteria, resulting in poor reactor startup and performance. To determine the best approach for improving startup

  17. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    Logan, Bruce E.; Call, Douglas; Cheng, Shaoan; Hamelers, Hubertus V. M.; Sleutels, Tom H. J. A.; Jeremiasse, Adriaan W.; Rozendal, René A.

    2008-01-01

    production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here

  18. Microbial electrolysis desalination and chemical-production cell for CO2 sequestration

    Zhu, Xiuping; Logan, Bruce E.

    2014-01-01

    Mineral carbonation can be used for CO2 sequestration, but the reaction rate is slow. In order to accelerate mineral carbonation, acid generated in a microbial electrolysis desalination and chemical-production cell (MEDCC) was examined to dissolve

  19. Concomitant use of polarization and positive phase contrast microscopy for the study of microbial cells

    Žižka, Zdeněk; Gabriel, Jiří

    2014-01-01

    Roč. 60, č. 6 (2014), s. 545-550 ISSN 0015-5632 Institutional support: RVO:61388971 Keywords : microbial cells * microscopy * microorganism Subject RIV: EE - Microbiology, Virology Impact factor: 1.000, year: 2014

  20. Novel anti-flooding poly(dimethylsiloxane) (PDMS) catalyst binder for microbial fuel cell cathodes

    Zhang, Fang; Chen, Guang; Hickner, Michael A.; Logan, Bruce E.

    2012-01-01

    Poly(dimethylsiloxane) (PDMS) was investigated as an alternative to Nafion as an air cathode catalyst binder in microbial fuel cells (MFCs). Cathodes were constructed around either stainless steel (SS) mesh or copper mesh using PDMS as both catalyst

  1. Concomitant use of polarization and positive phase contrast microscopy for the study of microbial cells

    Žižka, Zdeněk; Gabriel, Jiří

    2015-01-01

    Roč. 60, č. 6 (2015), s. 545-550 ISSN 0015-5632 Institutional support: RVO:61388971 Keywords : polarization microscopy * microbial cells * positive phase contrast Subject RIV: EE - Microbiology, Virology Impact factor: 1.335, year: 2015

  2. Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

    Zhu, Xiuping; Hatzell, Marta C.; Cusick, Roland D.; Logan, Bruce E.

    2013-01-01

    A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions

  3. Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells

    Liu, Jia; Geise, Geoffrey M.; Luo, Xi; Hou, Huijie; Zhang, Fang; Feng, Yujie; Hickner, Michael A.; Logan, Bruce E.

    2014-01-01

    Power production in microbial reverse-electrodialysis cells (MRCs) can be limited by the internal resistance of the reverse electrodialysis stack. Typical MRC stacks use non-conductive spacers that block ion transport by the so-called spacer shadow

  4. Impact of salinity on cathode catalyst performance in microbial fuel cells (MFCs)

    Wang, Xi; Cheng, Shaoan; Zhang, Xiaoyuan; Li, Xiao-yan; Logan, Bruce E.

    2011-01-01

    Several alternative cathode catalysts have been proposed for microbial fuel cells (MFCs), but effects of salinity (sodium chloride) on catalyst performance, separate from those of conductivity on internal resistance, have not been previously

  5. A quantitative method to evaluate microbial electrolysis cell effectiveness for energy recovery and wastewater treatment

    Ivanov, Ivan; Ren, Lijiao; Siegert, Michael; Logan, Bruce E.

    2013-01-01

    Microbial electrolysis cells (MECs) are potential candidates for sustainable wastewater treatment as they allow for recovery of the energy input by producing valuable chemicals such as hydrogen gas. Evaluating the effectiveness of MEC treatment

  6. Synthetic Biology and Microbial Fuel Cells: Towards Self-Sustaining Life Support Systems

    National Aeronautics and Space Administration — NASA ARC and the J. Craig Venter Institute (JCVI) collaborated to investigate the development of advanced microbial fuels cells (MFCs) for biological wastewater...

  7. Electricity generation of single-chamber microbial fuel cells at low temperatures

    Cheng, Shaoan; Xing, Defeng; Logan, Bruce E.

    2011-01-01

    Practical applications of microbial fuel cells (MFCs) for wastewater treatment will require operation of these systems over a wide range of wastewater temperatures. MFCs at room or higher temperatures (20-35°C) are relatively well studied compared

  8. Hydrogen Generation in Microbial Reverse-Electrodialysis Electrolysis Cells Using a Heat-Regenerated Salt Solution

    Nam, Joo-Youn; Cusick, Roland D.; Kim, Younggy; Logan, Bruce E.

    2012-01-01

    Hydrogen gas can be electrochemically produced in microbial reverse-electrodialysis electrolysis cells (MRECs) using current derived from organic matter and salinity-gradient energy such as river water and seawater solutions. Here, it is shown

  9. Nano-watt fueling from a micro-scale microbial fuel cell using black tea waste

    Rojas, Jhonathan Prieto; Alqarni, Wejdan Mohammed Mofleh; Kalantan, Kalthom Kamil Saleh; Hussain, Muhammad Mustafa; Mink, Justine E.

    2016-01-01

    In this report, we show the rapid assessment of black tea as potential fuel to power up nanopower systems using a microsized, simplistic and sustainable air-cathode microbial fuel cell. It was found that tea produced more power compared

  10. Investigation of the microbial metabolism of carbon dioxide and hydrogen in the kangaroo foregut by stable isotope probing.

    Godwin, Scott; Kang, Alicia; Gulino, Lisa-Maree; Manefield, Mike; Gutierrez-Zamora, Maria-Luisa; Kienzle, Marco; Ouwerkerk, Diane; Dawson, Kerri; Klieve, Athol V

    2014-09-01

    Kangaroos ferment forage material in an enlarged forestomach analogous to the rumen, but in contrast to ruminants, they produce little or no methane. The objective of this study was to identify the dominant organisms and pathways involved in hydrogenotrophy in the kangaroo forestomach, with the broader aim of understanding how these processes are able to predominate over methanogenesis. Stable isotope analysis of fermentation end products and RNA stable isotope probing (RNA-SIP) were used to investigate the organisms and biochemical pathways involved in the metabolism of hydrogen and carbon dioxide in the kangaroo forestomach. Our results clearly demonstrate that the activity of bacterial reductive acetogens is a key factor in the reduced methane output of kangaroos. In in vitro fermentations, the microbial community of the kangaroo foregut produced very little methane, but produced a significantly greater proportion of acetate derived from carbon dioxide than the microbial community of the bovine rumen. A bacterial operational taxonomic unit closely related to the known reductive acetogen Blautia coccoides was found to be associated with carbon dioxide and hydrogen metabolism in the kangaroo foregut. Other bacterial taxa including members of the genera Prevotella, Oscillibacter and Streptococcus that have not previously been reported as containing hydrogenotrophic organisms were also significantly associated with metabolism of hydrogen and carbon dioxide in the kangaroo forestomach.

  11. Establishment and metabolic analysis of a model microbial community for understanding trophic and electron accepting interactions of subsurface anaerobic environments

    Yang Zamin K

    2010-05-01

    Full Text Available Abstract Background Communities of microorganisms control the rates of key biogeochemical cycles, and are important for biotechnology, bioremediation, and industrial microbiological processes. For this reason, we constructed a model microbial community comprised of three species dependent on trophic interactions. The three species microbial community was comprised of Clostridium cellulolyticum, Desulfovibrio vulgaris Hildenborough, and Geobacter sulfurreducens and was grown under continuous culture conditions. Cellobiose served as the carbon and energy source for C. cellulolyticum, whereas D. vulgaris and G. sulfurreducens derived carbon and energy from the metabolic products of cellobiose fermentation and were provided with sulfate and fumarate respectively as electron acceptors. Results qPCR monitoring of the culture revealed C. cellulolyticum to be dominant as expected and confirmed the presence of D. vulgaris and G. sulfurreducens. Proposed metabolic modeling of carbon and electron flow of the three-species community indicated that the growth of C. cellulolyticum and D. vulgaris were electron donor limited whereas G. sulfurreducens was electron acceptor limited. Conclusions The results demonstrate that C. cellulolyticum, D. vulgaris, and G. sulfurreducens can be grown in coculture in a continuous culture system in which D. vulgaris and G. sulfurreducens are dependent upon the metabolic byproducts of C. cellulolyticum for nutrients. This represents a step towards developing a tractable model ecosystem comprised of members representing the functional groups of a trophic network.

  12. Modified Gold Electrode and Hollow Mn3O4 Nanoparticles as Electrode Materials for Microbial Fuel Cell Applications

    Dhungana, Pramod

    Microbial fuel cell (MFC) technology has attracted great attention in the scientific community as it offers the possibility of extraction of electricity from wide range of soluble and dissolved organic waste or renewable biomass, including sludge, waste water and cellulosic biomass. Microbial fuel cells are devices that utilize microbial metabolic processes to convert chemical energy via the oxidation of organic substances to produce electric current. MFCs consist of two chambers, an anode and cathode, separated by ion-permeable materials. The efficiency of producing electricity using the MFC depends on several factors such as immobilization of microorganisms on anode, mode of electron transfer, types of substrate/fuel and effectiveness of cathode materials for oxygen reduction reaction (ORR). In this work, in order to immobilize the microorganisms on anode materials, we have investigated the surface modification of gold electrode (anode) using alkyl dithiol and aryl thiol with glucose. The modification processes were characterized by using contact angle measurements and proton nuclear magnetic resonance (NMR). In order to study the effectiveness of cathode materials for ORR, we have synthesized hollow Mn3O 4 nanoparticles which are electrically very poor. Therefore, the hollow nanoparticles were mixed with electrically conductive multi-walled carbon nanotube as support and optimized the mixing process. This composite material shows enhanced ORR activity in all types of pH conditions. In future, we will focus to integrate anode and cathode in MFC to check its efficiency to produce electricity.

  13. Neutral hydrophilic cathode catalyst binders for microbial fuel cells

    Saito, Tomonori

    2011-01-01

    Improving oxygen reduction in microbial fuel cell (MFC) cathodes requires a better understanding of the effects of the catalyst binder chemistry and properties on performance. A series of polystyrene-b-poly(ethylene oxide) (PS-b-PEO) polymers with systematically varying hydrophilicity were designed to determine the effect of the hydrophilic character of the binder on cathode performance. Increasing the hydrophilicity of the PS-b-PEO binders enhanced the electrochemical response of the cathode and MFC power density by ∼15%, compared to the hydrophobic PS-OH binder. Increased cathode performance was likely a result of greater water uptake by the hydrophilic binder, which would increase the accessible surface area for oxygen reduction. Based on these results and due to the high cost of PS-b-PEO, the performance of an inexpensive hydrophilic neutral polymer, poly(bisphenol A-co-epichlorohydrin) (BAEH), was examined in MFCs and compared to a hydrophilic sulfonated binder (Nafion). MFCs with BAEH-based cathodes with two different Pt loadings initially (after 2 cycles) had lower MFC performance (1360 and 630 mW m-2 for 0.5 and 0.05 mg Pt cm-2) than Nafion cathodes (1980 and 1080 mW m -2 for 0.5 and 0.05 mg Pt cm-2). However, after long-term operation (22 cycles, 40 days), power production of each cell was similar (∼1200 and 700-800 mW m-2 for 0.5 and 0.05 mg Pt cm-2) likely due to cathode biofouling that could not be completely reversed through physical cleaning. While binder chemistry could improve initial electrochemical cathode performance, binder materials had less impact on overall long-term MFC performance. This observation suggests that long-term operation of MFCs will require better methods to avoid cathode biofouling. © 2011 The Royal Society of Chemistry.

  14. A Kinetic Modelling of Enzyme Inhibitions in the Central Metabolism of Yeast Cells

    Kasbawati; Kalondeng, A.; Aris, N.; Erawaty, N.; Azis, M. I.

    2018-03-01

    Metabolic regulation plays an important role in the metabolic engineering of a cellular process. It is conducted to improve the productivity of a microbial process by identifying the important regulatory nodes of a metabolic pathway such as fermentation pathway. Regulation of enzymes involved in a particular pathway can be held to improve the productivity of the system. In the central metabolism of yeast cell, some enzymes are known as regulating enzymes that can be inhibited to increase the production of ethanol. In this research we study the kinetic modelling of the enzymes in the central pathway of yeast metabolism by taking into consideration the enzyme inhibition effects to the ethanol production. The existence of positive steady state solution and the stability of the system are also analysed to study the property and dynamical behaviour of the system. One stable steady state of the system is produced if some conditions are fulfilled. The conditions concern to the restriction of the maximum reactions of the enzymes in the pyruvate and acetaldehyde branch points. There exists a certain time of fermentation reaction at which a maximum and a minimum ethanol productions are attained after regulating the system. Optimal ethanol concentration is also produced for a certain initial concentration of inhibitor.

  15. Mitochondrial metabolism in hematopoietic stem cells requires functional FOXO3

    Rimmelé, Pauline; Liang, Raymond; Bigarella, Carolina L; Kocabas, Fatih; Xie, Jingjing; Serasinghe, Madhavika N; Chipuk, Jerry; Sadek, Hesham; Zhang, Cheng Cheng; Ghaffari, Saghi

    2015-01-01

    Hematopoietic stem cells (HSC) are primarily dormant but have the potential to become highly active on demand to reconstitute blood. This requires a swift metabolic switch from glycolysis to mitochondrial oxidative phosphorylation. Maintenance of low levels of reactive oxygen species (ROS), a by-product of mitochondrial metabolism, is also necessary for sustaining HSC dormancy. Little is known about mechanisms that integrate energy metabolism with hematopoietic stem cell homeostasis. Here, we identify the transcription factor FOXO3 as a new regulator of metabolic adaptation of HSC. ROS are elevated in Foxo3−/− HSC that are defective in their activity. We show that Foxo3−/− HSC are impaired in mitochondrial metabolism independent of ROS levels. These defects are associated with altered expression of mitochondrial/metabolic genes in Foxo3−/− hematopoietic stem and progenitor cells (HSPC). We further show that defects of Foxo3−/− HSC long-term repopulation activity are independent of ROS or mTOR signaling. Our results point to FOXO3 as a potential node that couples mitochondrial metabolism with HSC homeostasis. These findings have critical implications for mechanisms that promote malignant transformation and aging of blood stem and progenitor cells. PMID:26209246

  16. Microbial Metabolism in Soil at Subzero Temperatures: Adaptation Mechanisms Revealed by Position-Specific 13C Labeling

    Ezekiel K. Bore

    2017-05-01

    Full Text Available Although biogeochemical models designed to simulate carbon (C and nitrogen (N dynamics in high-latitude ecosystems incorporate extracellular parameters, molecular and biochemical adaptations of microorganisms to freezing remain unclear. This knowledge gap hampers estimations of the C balance and ecosystem feedback in high-latitude regions. To analyze microbial metabolism at subzero temperatures, soils were incubated with isotopomers of position-specifically 13C-labeled glucose at three temperatures: +5 (control, -5, and -20°C. 13C was quantified in CO2, bulk soil, microbial biomass, and dissolved organic carbon (DOC after 1, 3, and 10 days and also after 30 days for samples at -20°C. Compared to +5°C, CO2 decreased 3- and 10-fold at -5 and -20°C, respectively. High 13C recovery in CO2 from the C-1 position indicates dominance of the pentose phosphate pathway at +5°C. In contrast, increased oxidation of the C-4 position at subzero temperatures implies a switch to glycolysis. A threefold higher 13C recovery in microbial biomass at -5 than +5°C points to synthesis of intracellular compounds such as glycerol and ethanol in response to freezing. Less than 0.4% of 13C was recovered in DOC after 1 day, demonstrating complete glucose uptake by microorganisms even at -20°C. Consequently, we attribute the fivefold higher extracellular 13C in soil than in microbial biomass to secreted antifreeze compounds. This suggests that with decreasing temperature, intracellular antifreeze protection is complemented by extracellular mechanisms to avoid cellular damage by crystallizing water. The knowledge of sustained metabolism at subzero temperatures will not only be useful for modeling global C dynamics in ecosystems with periodically or permanently frozen soils, but will also be important in understanding and controlling the adaptive mechanisms of food spoilage organisms.

  17. Methane Metabolizing Microbial Communities in the Cold Seep Areas in the Northern Continental Shelf of South China Sea

    Wang, F.; Liang, Q.

    2016-12-01

    Marine sediment contains large amount of methane, estimated approximately 500-2500 gigatonnes of dissolved and hydrated methane carbon stored therein, mainly in continental margins. In localized specific areas named cold seeps, hydrocarbon (mainly methane) containing fluids rise to the seafloor, and support oases of ecosystem composed of various microorganisms and faunal assemblages. South China Sea (SCS) is surrounded by passive continental margins in the west and north and convergent margins in the south and east. Thick organic-rich sediments have accumulated in the SCS since the late Mesozoic, which are continuing sources to form gas hydrates in the sediments of SCS. Here, Microbial ecosystems, particularly those involved in methane transformations were investigated in the cold seep areas (Qiongdongnan, Shenhu, and Dongsha) in the northern continental shelf of SCS. Multiple interdisciplinary analytic tools such as stable isotope probing, geochemical analysis, and molecular ecology, were applied for a comprehensive understanding of the microbe mediated methane transformation in this project. A variety of sediments cores have been collected, the geochemical profiles and the associated microbial distribution along the sediment cores were recorded. The major microbial groups involved in the methane transformation in these sediment cores were revealed, known methane producing and oxidizing archaea including Methanosarcinales, anaerobic methane oxidizing groups ANME-1, ANME-2 and their niche preference in the SCS sediments were found. In-depth comparative analysis revealed the presence of SCS-specific archaeal subtypes which probably reflected the evolution and adaptation of these methane metabolizing microbes to the SCS environmental conditions. Our work represents the first comprehensive analysis of the methane metabolizing microbial communities in the cold seep areas along the northern continental shelf of South China Sea, would provide new insight into the

  18. Perspectives on research and development of microbial fuel cells

    Ortega-Martinez, A.; Vazquez Larios, A.L.; Solorza-Feria, O.; Poggi Varaldo, H.M. [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: hectorpoggi2001@gmail.com; rareli@hotmail.com

    2009-09-15

    Microbial fuel cells (MFC), is an anoxic electrochemical bioreactor where bacteria grow in the absence of oxygen in a chamber containing an anode which it may be covered by a biofilm. Microorganisms anoxically oxidize the organic substrate and electrons generated are released to the anode. Released protons are transferred to the cathode. Natural or forced aeration of the cathode supplies the oxygen for the final reaction 2H{sup +} + 2e{sup -} + (1/2) O{sub 2} = H{sub 2}O. In this work, we present a critical review on MFC focused on subjects that are receiving a growing interest from the research and technological communities: (i) types of MFC, their relative advantages and disadvantages and ranges of application; (ii) development of biocathodes; (iii) enrichment procedures of microbial communities in MFC. Recent research shows that one-chamber fitted with cathode aerated by natural aeration, and other special types of high performance MFC, have displaced the historical two-chamber MFC. Recent studies showed that electrochemically active bacteria (EAB) can be successfully enriched in MFC. The cost and eventual poisoning of the platinum catalyst used at the cathode is a major limitation to MFC application and economic viability. Researchers have started working on the concept of biocathodes that would use bacteria instead of platinum as a biocatalyst. Microbial enrichment of inocula seeded to MFC may provide a way to enrich the consortium with EAB, thus substantially increasing the transfer of electrons to the anode. Bioaugmentation of consortia in MFC with strains EAB, could contribute to the same goal. [Spanish] Las celdas de combustible microbianas (CCM) son un biorrector anoxico donde las bacterias crecen en ausencia de oxigeno en una camara que contiene un anodo que puede cubrirse con una biopelicula. Los microorganismos oxidan onoxicamente el sustrato organico y los electrones generados se liberan al anodo. Los protones liberados se transfieren al catodo. La

  19. Influence of different yeast cell wall preparations and their components on performance and immune and metabolic pathways in Clostridium perfringens-challenged broiler chicks

    A study was conducted to evaluate the influence of purification of yeast cell wall (YCW) preparations on broiler performance, and immunogenic and metabolic pathways under microbial challenge. A total of 240 day-of-hatch chicks were distributed among two battery brooder units (48 pens; 5 birds/pen; ...

  20. 2012 Molecular Basis of Microbial One-Carbon Metabolism Gordon Research Conferences and Gordon Research Seminar, August 4-10,2012

    Hanson, Thomas

    2012-08-10

    The 2012 Gordon Conference will present and discuss cutting-edge research in the field of microbial metabolism of C1 compounds. The conference will feature the roles and application of C1 metabolism in natural and synthetic systems at scales from molecules to ecosystems. The conference will stress molecular aspects of the unique metabolism exhibited by autotrophic bacteria, methanogens, methylotrophs, aerobic and anaerobic methanotrophs, and acetogens.

  1. Size and Carbon Content of Sub-seafloor Microbial Cells at Landsort Deep, Baltic Sea

    Braun, Stefan; Morono, Yuki; Littmann, Sten

    2016-01-01

    determined the volume and the carbon content of microbial cells from a marine sediment drill core retrieved by the Integrated Ocean Drilling Program (IODP), Expedition 347, at Landsort Deep, Baltic Sea. To determine their shape and volume, cells were separated from the sediment matrix by multi-layer density......-specific carbon content was 19–31 fg C cell−1, which is at the lower end of previous estimates that were used for global estimates of microbial biomass. The cell-specific carbon density increased with sediment depth from about 200 to 1000 fg C μm−3, suggesting that cells decrease their water content and grow...... small cell sizes as adaptation to the long-term subsistence at very low energy availability in the deep biosphere. We present for the first time depth-related data on the cell volume and carbon content of sedimentary microbial cells buried down to 60 m below the seafloor. Our data enable estimates...

  2. Bacterial communities associated with Shinkaia crosnieri from the Iheya North, Okinawa Trough: Microbial diversity and metabolic potentials

    Zhang, Jian; Zeng, Zhi-gang; Chen, Shuai; Sun, Li

    2018-04-01

    Shinkaia crosnieri is a galatheid crab endemic to the deep-sea hydrothermal systems in the Okinawa Trough. In this study, we systematically analyzed and compared the diversity and metabolic potentials of the microbial communities in different tissues (setae, gill, and intestine) of S. crosnieri by high-throughput sequencing technology and quantitative real-time polymerase chain reaction. Sequence analysis based on the V3-V4 regions of the 16S rRNA gene obtained 408,079 taxon tags, which covered 15 phyla, 22 classes, 32 orders, 42 families, and 25 genera. Overall, the microbial communities in all tissues were dominated by Epsilonproteobacteria and Gammaproteobacteria, of which Epsilonproteobacteria was the largest class and accounted for 85.24% of the taxon tags. In addition, 20 classes of bacteria were discovered for the first time to be associated with S. crosnieri and no archaea were detected. Comparative analysis showed that (i) bacteria from different tissues fell into different groups by β-diversity analysis, (ii) bacterial communities in intestine were similar to that in gill and much more diverse than that in setae, and the sulfur-oxidizing genus Sulfurovum was markedly enriched in intestine and gill. Furthermore, bacteria potentially involved in methane, nitrogen, and metal metabolisms were detected in all samples. The key genes of aprA/dsrA and pmoA involved in sulfate reducing and methane oxidization, respectively, were detected in the gill and gut communities for the first time, and pmoA was significantly more abundant in gill and setae than in intestine. These results provide the first comparative and relatively complete picture of the diversity and metabolic potentials of the bacteria in different tissues of S. crosnieri. These results also indicate that the composition of the microbial communities in hydrothermal fauna changes with time, suggesting the importance of environmental influence.

  3. Cell-selective metabolic labeling of biomolecules with bioorthogonal functionalities.

    Xie, Ran; Hong, Senlian; Chen, Xing

    2013-10-01

    Metabolic labeling of biomolecules with bioorthogonal functionalities enables visualization, enrichment, and analysis of the biomolecules of interest in their physiological environments. This versatile strategy has found utility in probing various classes of biomolecules in a broad range of biological processes. On the other hand, metabolic labeling is nonselective with respect to cell type, which imposes limitations for studies performed in complex biological systems. Herein, we review the recent methodological developments aiming to endow metabolic labeling strategies with cell-type selectivity. The cell-selective metabolic labeling strategies have emerged from protein and glycan labeling. We envision that these strategies can be readily extended to labeling of other classes of biomolecules. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. New paradigms for metabolic modeling of human cells

    Mardinoglu, Adil; Nielsen, Jens

    2015-01-01

    review recent work on reconstruction of GEMs for human cell/tissue types and cancer, and the use of GEMs for identification of metabolic changes occurring in response to disease development. We further discuss how GEMs can be used for the development of efficient therapeutic strategies. Finally......, challenges in integration of cell/tissue models for simulation of whole body functions as well as integration of GEMs with other biological networks for generating complete cell/tissue models are presented.......Abnormalities in cellular functions are associated with the progression of human diseases, often resulting in metabolic reprogramming. GEnome-scale metabolic Models (GEMs) have enabled studying global metabolic reprogramming in connection with disease development in a systematic manner. Here we...

  5. Cell adsorption and selective desorption for separation of microbial cells by using chitosan-immobilized silica.

    Kubota, Munehiro; Matsui, Masayoshi; Chiku, Hiroyuki; Kasashima, Nobuyuki; Shimojoh, Manabu; Sakaguchi, Kengo

    2005-12-01

    Cell adsorption and selective desorption for separation of microbial cells were conducted by using chitosan-immobilized silica (CIS). When chitosan was immobilized onto silica surfaces with glutaraldehyde, bacterial cells adsorbed well and retained viability. Testing of the adsorption and desorption ability of CIS using various microbes such as Escherichia coli, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus casei, Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Saccharomyces cerevisiae, Saccharomyces ludwigii, and Schizosaccharomyces pombe revealed that most microbes could be adsorbed and selectively desorbed under different conditions. In particular, recovery was improved when L-cysteine was added. A mixture of two bacterial strains adsorbed onto CIS could also be successfully separated by use of specific solutions for each strain. Most of the desorbed cells were alive. Thus, quantitative and selective fractionation of cells is readily achievable by employing chitosan, a known antibacterial material.

  6. Microbial Communities and Their Predicted Metabolic Functions in Growth Laminae of a Unique Large Conical Mat from Lake Untersee, East Antarctica

    Hyunmin Koo

    2017-08-01

    Full Text Available In this study, we report the distribution of microbial taxa and their predicted metabolic functions observed in the top (U1, middle (U2, and inner (U3 decadal growth laminae of a unique large conical microbial mat from perennially ice-covered Lake Untersee of East Antarctica, using NextGen sequencing of the 16S rRNA gene and bioinformatics tools. The results showed that the U1 lamina was dominated by cyanobacteria, specifically Phormidium sp., Leptolyngbya sp., and Pseudanabaena sp. The U2 and U3 laminae had high abundances of Actinobacteria, Verrucomicrobia, Proteobacteria, and Bacteroidetes. Closely related taxa within each abundant bacterial taxon found in each lamina were further differentiated at the highest taxonomic resolution using the oligotyping method. PICRUSt analysis, which determines predicted KEGG functional categories from the gene contents and abundances among microbial communities, revealed a high number of sequences belonging to carbon fixation, energy metabolism, cyanophycin, chlorophyll, and photosynthesis proteins in the U1 lamina. The functional predictions of the microbial communities in U2 and U3 represented signal transduction, membrane transport, zinc transport and amino acid-, carbohydrate-, and arsenic- metabolisms. The Nearest Sequenced Taxon Index (NSTI values processed through PICRUSt were 0.10, 0.13, and 0.11 for U1, U2, and U3 laminae, respectively. These values indicated a close correspondence with the reference microbial genome database, implying high confidence in the predicted metabolic functions of the microbial communities in each lamina. The distribution of microbial taxa observed in each lamina and their predicted metabolic functions provides additional insight into the complex microbial ecosystem at Lake Untersee, and lays the foundation for studies that will enhance our understanding of the mechanisms responsible for the formation of these unique mat structures and their evolutionary significance.

  7. Metabolic Regulation of a Bacterial Cell System with Emphasis on Escherichia coli Metabolism

    Shimizu, Kazuyuki

    2013-01-01

    It is quite important to understand the overall metabolic regulation mechanism of bacterial cells such as Escherichia coli from both science (such as biochemistry) and engineering (such as metabolic engineering) points of view. Here, an attempt was made to clarify the overall metabolic regulation mechanism by focusing on the roles of global regulators which detect the culture or growth condition and manipulate a set of metabolic pathways by modulating the related gene expressions. For this, it was considered how the cell responds to a variety of culture environments such as carbon (catabolite regulation), nitrogen, and phosphate limitations, as well as the effects of oxygen level, pH (acid shock), temperature (heat shock), and nutrient starvation. PMID:25937963

  8. Diversity and function of the microbial community on anodes of sediment microbial fuel cells fueled by root exudates

    Cabezas da Rosa, Angela

    2010-11-26

    Anode microbial communities are essential for current production in microbial fuel cells. Anode reducing bacteria are capable of using the anode as final electron acceptor in their respiratory chain. The electrons delivered to the anode travel through a circuit to the cathode where they reduce oxygen to water generating an electric current. A novel type of sediment microbial fuel cell (SMFC) harvest energy from photosynthetically derived compounds released through the roots. Nothing is known about anode microbial communities of this type of microbial fuel cell. This work consists of three parts. The first part focuses on the study of bacterial and archaeal community compositions on anodes of SMFCs fueled by rice root exudates. By using terminal restriction fragment length polymorphism (T-RFLP), a profiling technique, and cloning / sequencing of 16S rRNA, we determined that the support type used for the plant (vermiculite, potting soil or rice field soil) is an important factor determining the composition of the microbial community. Finally, by comparing microbial communities of current producing anodes and non-current producing controls we determined that Desulfobulbus- and Geobacter-related populations were probably most important for current production in potting soil and rice field soil SMFCs, respectively. However, {delta}-proteobacterial Anaeromyxobacter spp., unclassified {delta}-proteobacteria and Anaerolineae were also part of the anode biofilm in rice field soil SMFCs and these populations might also play a role in current production. Moreover, distinct clusters of Geobacter and Anaeromyxobacter populations were stimulated by rice root exudates. Regarding Archaea, uncultured Euryarchaea were abundant on anodes of potting soil SMFCs indicating a potential role in current production. In both, rice field soil and potting soil SMFCs, a decrease of Methanosaeta, an acetotrophic methanogen, was detected on current producing anodes. In the second part we focused

  9. The woodrat gut microbiota as an experimental system for understanding microbial metabolism of dietary toxins

    Kevin D. Kohl

    2016-07-01

    Full Text Available The microbial communities inhabiting the alimentary tracts of mammals, particularly those of herbivores, are estimated to be one of the densest microbial reservoirs on Earth. The significance of these gut microbes in influencing the physiology, ecology and evolution of their hosts is only beginning to be realized. To understand the microbiome of herbivores with a focus on nutritional ecology, while evaluating the roles of host evolution and environment in sculpting microbial diversity, we have developed an experimental system consisting of the microbial communities of several species of herbivorous woodrats (genus Neotoma that naturally feed on a variety of dietary toxins. We designed this system to investigate the long-standing, but experimentally neglected hypothesis that ingestion of toxic diets by herbivores is facilitated by the gut microbiota. Like several other rodent species, the woodrat stomach has a sacculated, nongastric foregut portion. We have documented a dense and diverse community of microbes in the woodrat foregut, with several genera potentially capable of degrading dietary toxins and/or playing a role in stimulating hepatic detoxification enzymes of the host. The biodiversity of these gut microbes appears to be a function of host evolution, ecological experience and diet, such that dietary toxins increase microbial diversity in hosts with experience with these toxins while novel toxins depress microbial diversity. These microbial communities are critical to the ingestion of a toxic diet as reducing the microbial community with antibiotics impairs the host’s ability to feed on dietary toxins. Furthermore, the detoxification capacity of gut microbes can be transferred from Neotoma both intra and interspecifically to naïve animals that lack ecological and evolutionary history with these toxins. In addition to advancing our knowledge of complex host-microbes interactions, this system holds promise for identifying microbes that

  10. Molecular Basis of Microbial One-Carbon Metabolism 2008 Gordon Research Conference (July 20-25, 2008)

    Stephen W. Ragsdale

    2009-08-12

    One-carbon (C-1) compounds play a central role in microbial metabolism. C-1 compounds include methane, carbon monoxide, CO2, and methanol as well as coenzyme-bound one-carbon compounds (methyl-B12, CH3-H4folate, etc). Such compounds are of broad global importance because several C-1 compounds (e.g., CH4) are important energy sources, some (e.g., CO2 and CH4) are potent greenhouse gases, and others (e.g., CH2Cl2) are xenobiotics. They are central in pathways of energy metabolism and carbon fixation by microbes and many are of industrial interest. Research on the pathways of one-carbon metabolism has added greatly to our understanding of evolution, structural biology, enzyme mechanisms, gene regulation, ecology, and applied biology. The 2008 meeting will include recent important findings in the following areas: (a) genomics, metagenomics, and proteomic studies that have expanded our understanding of autotrophy and C-1 metabolism and the evolution of these pathways; (b) redox regulation of carbon cycles and the interrelationship between the carbon cycle and other biogeochemical cycles (sulfur, nitrogen, oxygen); (c) novel pathways for carbon assimilation; (d) biotechnology related to C-1 metabolism; (e) novel enzyme mechanisms including channeling of C-1 intermediates during metabolism; and (f) the relationship between metal homeostasis and the global carbon cycle. The conference has a diverse and gender-balanced slate of speakers and session leaders. The wide variety of disciplines brought to the study of C-1 metabolism make the field an excellent one in which to train young researchers.

  11. Analysis of the functional gene structure and metabolic potential of microbial community in high arsenic groundwater.

    Li, Ping; Jiang, Zhou; Wang, Yanhong; Deng, Ye; Van Nostrand, Joy D; Yuan, Tong; Liu, Han; Wei, Dazhun; Zhou, Jizhong

    2017-10-15

    Microbial functional potential in high arsenic (As) groundwater ecosystems remains largely unknown. In this study, the microbial community functional composition of nineteen groundwater samples was investigated using a functional gene array (GeoChip 5.0). Samples were divided into low and high As groups based on the clustering analysis of geochemical parameters and microbial functional structures. The results showed that As related genes (arsC, arrA), sulfate related genes (dsrA and dsrB), nitrogen cycling related genes (ureC, amoA, and hzo) and methanogen genes (mcrA, hdrB) in groundwater samples were correlated with As, SO 4 2- , NH 4 + or CH 4 concentrations, respectively. Canonical correspondence analysis (CCA) results indicated that some geochemical parameters including As, total organic content, SO 4 2- , NH 4 + , oxidation-reduction potential (ORP) and pH were important factors shaping the functional microbial community structures. Alkaline and reducing conditions with relatively low SO 4 2- , ORP, and high NH 4 + , as well as SO 4 2- and Fe reduction and ammonification involved in microbially-mediated geochemical processes could be associated with As enrichment in groundwater. This study provides an overall picture of functional microbial communities in high As groundwater aquifers, and also provides insights into the critical role of microorganisms in As biogeochemical cycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Continuous power generation and microbial community structure of the anode biofilms in a three-stage microbial fuel cell system

    Chung, Kyungmi; Okabe, Satoshi [Hokkaido Univ., Sapporo (Japan). Dept. of Urban and Environmental Engineering

    2009-07-15

    A mediator-less three-stage two-chamber microbial fuel cell (MFC) system was developed and operated continuously for more than 1.5 years to evaluate continuous power generation while treating artificial wastewater containing glucose (10 mM) concurrently. A stable power density of 28 W/m3 was attained with an anode hydraulic retention time of 4.5 h and phosphate buffer as the cathode electrolyte. An overall dissolved organic carbon removal ratio was about 85%, and coulombic efficiency was about 46% in this MFC system. We also analyzed the microbial community structure of anode biofilms in each MFC. Since the environment in each MFC was different due to passing on the products to the next MFC in series, the microbial community structure was different accordingly. The anode biofilm in the first MFC consisted mainly of bacteria belonging to the Gammaproteobacteria, identified as Aeromonas sp., while the Firmicutes dominated the anode biofilms in the second and third MFCs that were mainly fed with acetate. Cyclic voltammetric results supported the presence of a redox compound(s) associated with the anode biofilm matrix, rather than mobile (dissolved) forms, which could be responsible for the electron transfer to the anode. Scanning electron microscopy revealed that the anode biofilms were comprised of morphologically different cells that were firmly attached on the anode surface and interconnected each other with anchor-like filamentous appendages, which might support the results of cyclic voltammetry. (orig.)

  13. Environmental spread of microbes impacts the development of metabolic phenotypes in mice transplanted with microbial communities from humans

    Zhang, Li; Bahl, Martin Iain; Roager, Henrik Munch

    2017-01-01

    Microbiota transplantation to germ-free animals is a powerful method to study involvement of gut microbes in the aetiology of metabolic syndrome. Owing to large interpersonal variability in gut microbiota, studies with broad coverage of donors are needed to elucidate the establishment of human......, thereby allowing us to explore the extent of microbial spread between cages in a well-controlled environment. Despite high group-wise similarity between obese and control human microbiotas, transplanted mice in the four isolators developed distinct gut bacterial composition and activity, body mass gain......, and insulin resistance. Spread of microbes between cages within isolators interacted with establishment of the transplanted microbiotas in mice, and contributed to the transmission of metabolic phenotypes. Our findings highlight the impact of donor variability and reveal that inter-individual spread...

  14. Pluripotent Stem Cell Metabolism and Mitochondria: Beyond ATP

    Jarmon G. Lees

    2017-01-01

    Full Text Available Metabolism is central to embryonic stem cell (ESC pluripotency and differentiation, with distinct profiles apparent under different nutrient milieu, and conditions that maintain alternate cell states. The significance of altered nutrient availability, particularly oxygen, and metabolic pathway activity has been highlighted by extensive studies of their impact on preimplantation embryo development, physiology, and viability. ESC similarly modulate their metabolism in response to altered metabolite levels, with changes in nutrient availability shown to have a lasting impact on derived cell identity through the regulation of the epigenetic landscape. Further, the preferential use of glucose and anaplerotic glutamine metabolism serves to not only support cell growth and proliferation but also minimise reactive oxygen species production. However, the perinuclear localisation of spherical, electron-poor mitochondria in ESC is proposed to sustain ESC nuclear-mitochondrial crosstalk and a mitochondrial-H2O2 presence, to facilitate signalling to support self-renewal through the stabilisation of HIFα, a process that may be favoured under physiological oxygen. The environment in which a cell is grown is therefore a critical regulator and determinant of cell fate, with metabolism, and particularly mitochondria, acting as an interface between the environment and the epigenome.

  15. Glucose metabolism regulates T cell activation, differentiation and functions

    Clovis Steve Palmer

    2015-01-01

    Full Text Available The adaptive immune system is equipped to eliminate both tumors and pathogenic microorganisms. It requires a series of complex and coordinated signals to drive the activation, proliferation and differentiation of appropriate T cell subsets. It is now established that changes in cellular activation are coupled to profound changes in cellular metabolism. In addition, emerging evidence now suggest that specific metabolic alterations associated with distinct T cell subsets may be ancillary to their differentiation and influential in their immune functions. The Warburg effect originally used to describe a phenomenon in which most cancer cells relied on aerobic glycolysis for their growth is a key process that sustain T cell activation and differentiation. Here we review how different aspects of metabolism in T cells influence their functions, focusing on the emerging role of key regulators of glucose metabolism such as HIF-1α. A thorough understanding of the role of metabolism in T cell function could provide insights into mechanisms involved in inflammatory-mediated conditions, with the potential for developing novel therapeutic approaches to treat these diseases.

  16. Ammonia removal via microbial fuel cell (MFC) dynamic reactor

    Alabiad, I.; Ali, U. F. M.; Zakarya, I. A.; Ibrahim, N.; Radzi, R. W.; Zulkurnai, N. Z.; Azmi, N. H.

    2017-06-01

    Landfill leachate is generally known as high-strength wastewater that is difficult to handle and contains dissolved extracts and suspended matter. Microbial fuel cells (MFCs) were designed to treat landfill leachate while continuously producing power (voltage output). Three different anodes were tested in MFC reactors: carbon black, activated carbon, and zinc electrodes. Movements in the MFC reactor during treatment were also a key factor for testing. Results showed a difference in ammonia levels in the three anodes used. The study compared the efficiency of static and dynamic modes of MFC in removing ammonia. Continual leachate movement in the reactor could increase the rate of removal of the ammonia components. The setup provided a viable condition for maximum removal because the reactor movement caused the sludge to disintegrate, which allowed ammonia to separate easily from the parent leachate. Ammonia removal also resulted from the transfer of ammonium through the membrane or from ammonia loss. Constant exchange of ionic content benefited the MFC performance by increasing power production and decreasing internal electrode material resistance. This paper presents the results of the analyses of leachate treatment from the solid waste landfill located in Padang Siding Landfill, Perlis. The performance of ammonia removal was enhanced using different types of electrodes. In both modes, activated carbon performed better than black carbon and zinc. The respective percentages of ammonia removal for activated carbon of dynamic over static were 96.6%, 66.6%, and 92.8% for activated carbon, zinc, and black carbon. The results provide further information on the possibility of using MFCs in landfill leachate treatment systems.

  17. Power generation from furfural using the microbial fuel cell

    Luo, Yong; Liu, Guangli; Zhang, Renduo; Zhang, Cuiping [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275 (China)

    2010-01-01

    Furfural is a typical inhibitor in the ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In the literature, no report has shown that furfural can be utilized as the fuel to produce electricity in the microbial fuel cell (MFC), a device that uses microbes to convert organic compounds to generate electricity. In this study, we demonstrated that electricity was successfully generated using furfural as the sole fuel in both the ferricyanide-cathode MFC and the air-cathode MFC. In the ferricyanide-cathode MFC, the maximum power densities reached 45.4, 81.4, and 103 W m{sup -3}, respectively, when 1000 mg L{sup -1} glucose, a mixture of 200 mg L{sup -1} glucose and 5 mM furfural, and 6.68 mM furfural were used as the fuels in the anode solution. The corresponding Coulombic efficiencies (CE) were 4.0, 7.1, and 10.2% for the three treatments, respectively. For pure furfural as the fuel, the removal efficiency of furfural reached up to 95% within 12 h. In the air-cathode MFC using 6.68 mM furfural as the fuel, the maximum values of power density and CE were 361 mW m{sup -2} (18 W m{sup -3}) and 30.3%, respectively, and the COD removal was about 68% at the end of the experiment (about 30 h). Increase in furfural concentrations from 6.68 to 20 mM resulted in increase in the maximum power densities from 361 to 368 mW m{sup -2}, and decrease in CEs from 30.3 to 20.6%. These results indicated that some toxic and biorefractory organics such as furfural might still be suitable resources for electricity generation using the MFC technology. (author)

  18. Ovarian tumor-initiating cells display a flexible metabolism

    Anderson, Angela S. [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Roberts, Paul C. [Biomedical Science and Pathobiology, Virginia Tech, Blacksburg, VA (United States); Frisard, Madlyn I. [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Hulver, Matthew W., E-mail: hulvermw@vt.edu [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States); Schmelz, Eva M., E-mail: eschmelz@vt.edu [Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA (United States)

    2014-10-15

    An altered metabolism during ovarian cancer progression allows for increased macromolecular synthesis and unrestrained growth. However, the metabolic phenotype of cancer stem or tumor-initiating cells, small tumor cell populations that are able to recapitulate the original tumor, has not been well characterized. In the present study, we compared the metabolic phenotype of the stem cell enriched cell variant, MOSE-L{sub FFLv} (TIC), derived from mouse ovarian surface epithelial (MOSE) cells, to their parental (MOSE-L) and benign precursor (MOSE-E) cells. TICs exhibit a decrease in glucose and fatty acid oxidation with a concomitant increase in lactate secretion. In contrast to MOSE-L cells, TICs can increase their rate of glycolysis to overcome the inhibition of ATP synthase by oligomycin and can increase their oxygen consumption rate to maintain proton motive force when uncoupled, similar to the benign MOSE-E cells. TICs have an increased survival rate under limiting conditions as well as an increased survival rate when treated with AICAR, but exhibit a higher sensitivity to metformin than MOSE-E and MOSE-L cells. Together, our data show that TICs have a distinct metabolic profile that may render them flexible to adapt to the specific conditions of their microenvironment. By better understanding their metabolic phenotype and external environmental conditions that support their survival, treatment interventions can be designed to extend current therapy regimens to eradicate TICs. - Highlights: • Ovarian cancer TICs exhibit a decreased glucose and fatty acid oxidation. • TICs are more glycolytic and have highly active mitochondria. • TICs are more resistant to AICAR but not metformin. • A flexible metabolism allows TICs to adapt to their microenvironment. • This flexibility requires development of specific drugs targeting TIC-specific changes to prevent recurrent TIC outgrowth.

  19. Ovarian tumor-initiating cells display a flexible metabolism

    Anderson, Angela S.; Roberts, Paul C.; Frisard, Madlyn I.; Hulver, Matthew W.; Schmelz, Eva M.

    2014-01-01

    An altered metabolism during ovarian cancer progression allows for increased macromolecular synthesis and unrestrained growth. However, the metabolic phenotype of cancer stem or tumor-initiating cells, small tumor cell populations that are able to recapitulate the original tumor, has not been well characterized. In the present study, we compared the metabolic phenotype of the stem cell enriched cell variant, MOSE-L FFLv (TIC), derived from mouse ovarian surface epithelial (MOSE) cells, to their parental (MOSE-L) and benign precursor (MOSE-E) cells. TICs exhibit a decrease in glucose and fatty acid oxidation with a concomitant increase in lactate secretion. In contrast to MOSE-L cells, TICs can increase their rate of glycolysis to overcome the inhibition of ATP synthase by oligomycin and can increase their oxygen consumption rate to maintain proton motive force when uncoupled, similar to the benign MOSE-E cells. TICs have an increased survival rate under limiting conditions as well as an increased survival rate when treated with AICAR, but exhibit a higher sensitivity to metformin than MOSE-E and MOSE-L cells. Together, our data show that TICs have a distinct metabolic profile that may render them flexible to adapt to the specific conditions of their microenvironment. By better understanding their metabolic phenotype and external environmental conditions that support their survival, treatment interventions can be designed to extend current therapy regimens to eradicate TICs. - Highlights: • Ovarian cancer TICs exhibit a decreased glucose and fatty acid oxidation. • TICs are more glycolytic and have highly active mitochondria. • TICs are more resistant to AICAR but not metformin. • A flexible metabolism allows TICs to adapt to their microenvironment. • This flexibility requires development of specific drugs targeting TIC-specific changes to prevent recurrent TIC outgrowth

  20. Controlling cell-free metabolism through physiochemical perturbations.

    Karim, Ashty S; Heggestad, Jacob T; Crowe, Samantha A; Jewett, Michael C

    2018-01-01

    Building biosynthetic pathways and engineering metabolic reactions in cells can be time-consuming due to complexities in cellular metabolism. These complexities often convolute the combinatorial testing of biosynthetic pathway designs needed to define an optimal biosynthetic system. To simplify the optimization of biosynthetic systems, we recently reported a new cell-free framework for pathway construction and testing. In this framework, multiple crude-cell extracts are selectively enriched with individual pathway enzymes, which are then mixed to construct full biosynthetic pathways on the time scale of a day. This rapid approach to building pathways aids in the study of metabolic pathway performance by providing a unique freedom of design to modify and control biological systems for both fundamental and applied biotechnology. The goal of this work was to demonstrate the ability to probe biosynthetic pathway performance in our cell-free framework by perturbing physiochemical conditions, using n-butanol synthesis as a model. We carried out three unique case studies. First, we demonstrated the power of our cell-free approach to maximize biosynthesis yields by mapping physiochemical landscapes using a robotic liquid-handler. This allowed us to determine that NAD and CoA are the most important factors that govern cell-free n-butanol metabolism. Second, we compared metabolic profile differences between two different approaches for building pathways from enriched lysates, heterologous expression and cell-free protein synthesis. We discover that phosphate from PEP utilization, along with other physiochemical reagents, during cell-free protein synthesis-coupled, crude-lysate metabolic system operation inhibits optimal cell-free n-butanol metabolism. Third, we show that non-phosphorylated secondary energy substrates can be used to fuel cell-free protein synthesis and n-butanol biosynthesis. Taken together, our work highlights the ease of using cell-free systems to explore

  1. Polyamine metabolism in synchronously growing mammalian cells

    Heby, O.; Marton, L.J.; Gray, J.W.; Lindl, P.A.; Wilson, C.B.

    1976-03-02

    The times of synthesis of the polyamines putrescine, spermidine and spermine in relation to the cell cycle have been examined in Chinese hamster ovary (CHO) cells synchronized by selective detachment of mitotic cells. This technique produced cell populations with narrow age distributions. Following plating, the cells grew with high synchrony for more than one cell cycle in monolayer culture. At various times after plating, the distribution of cells among the G1, S and G2M phases of the cell cycle was calculated from DNA histograms obtained by flow microfluorometric analysis. At these same times L-ornithine decarboxylase assays and polyamine determinations showed that the synthesis of the polyamines was initiated in mid-G1 and that the polyamines started to accumulate towards the end of the G1 phase. Maximal rate of synthesis was obtained as the cells started to synthesize DNA and the highest polyamine content was obtained in the beginning of the S phase. Synthesis and accumulation of the polyamines decreased significantly during mid-S but towards the end of the S phase they increased again. The polyamine biosynthetic activity and the concentration of the polyamines reached a second maximum prior to cell division. The role of the polyamines in the traverse of the cell cycle and especially in the initiation or continuation of DNA synthesis is indicated also by the fact that fewer cells were found in the S phase when spermidine and spermine synthesis was inhibited by methylglyoxal-bis(guanylhydrazone).

  2. The Influence of Tallow on Rumen Metabolism, Microbial Biomass Synthesis and Fatty Acid Composition of Bacteria and Protozoa

    Weisbjerg, Martin Riis; Børsting, Christian Friis; Hvelplund, Torben

    1992-01-01

    Rumen metabolism, microbial biomass synthesis and microbial long chain fatty acid composition were studied in lactating cows fed at two levels of dry matter intake (L, 8.6 kg DM and H, 12.6 kg DM) with 0, 4 and 6% added tallow at the low feed level (L0, L4 and L6) and 0, 2, 4 and 6% at the high...... feed level (H0, H2, H4 and H6). Fibre digestibility was not significantly affected by tallow addition. Increasing tallow level in the diet decreased the total VFA concentration, the ratio of acetic acid to propionic acid and the ammonia concentration in the rumen. Crude fat and fatty acid content...... in bacterial and protozoal dry matter increased with increased tallow level, especially due to an increase in fatty acids originating from the feeds. Microbial synthesis in the rumen and flow of amino acids to the duodenum was highest for medium fat intake at the high feed level....

  3. Characterization of microbial metabolism of Syrah grape products in an in vitro colon model using targeted and non-targeted analytical approaches

    Aura, Anna-Marja; Mattila, Ismo; Hyötyläinen, Tuulia; Gopalacharyulu, Peddinti; Cheynier, Veronique; Souquet, Jean-Marc; Bes, Magali; Le Bourvellec, Carine; Guyot, Sylvain; Orešič, Matej

    2012-01-01

    Purpose Syrah red grapes are used in the production of tannin-rich red wines. Tannins are high molecular weight molecules, proanthocyanidins (PAs), and poorly absorbed in the upper intestine. In this study, gut microbial metabolism of Syrah grape phenolic compounds was investigated. Methods Syrah grape pericarp was subjected to an enzymatic in vitro digestion model, and red wine and grape skin PA fraction were prepared. Microbial conversion was screened using an in vitro colon model with faec...

  4. Starter Culture Selection for Making Chinese Sesame-Flavored Liquor Based on Microbial Metabolic Activity in Mixed-Culture Fermentation

    Wu, Qun; Ling, Jie

    2014-01-01

    Selection of a starter culture with excellent viability and metabolic activity is important for inoculated fermentation of traditional food. To obtain a suitable starter culture for making Chinese sesame-flavored liquor, the yeast and bacterium community structures were investigated during spontaneous and solid-state fermentations of this type of liquor. Five dominant species in spontaneous fermentation were identified: Saccharomyces cerevisiae, Pichia membranaefaciens, Issatchenkia orientalis, Bacillus licheniformis, and Bacillus amyloliquefaciens. The metabolic activity of each species in mixed and inoculated fermentations of liquor was investigated in 14 different cocultures that used different combinations of these species. The relationships between the microbial species and volatile metabolites were analyzed by partial least-squares (PLS) regression analysis. We found that S. cerevisiae was positively correlated to nonanal, and B. licheniformis was positively associated with 2,3-butanediol, isobutyric acid, guaiacol, and 4-vinyl guaiacol, while I. orientalis was positively correlated to butyric acid, isovaleric acid, hexanoic acid, and 2,3-butanediol. These three species are excellent flavor producers for Chinese liquor. Although P. membranaefaciens and B. amyloliquefaciens were not efficient flavor producers, the addition of them alleviated competition among the other three species and altered their growth rates and flavor production. As a result, the coculture of all five dominant species produced the largest amount of flavor compounds. The result indicates that flavor producers and microbial interaction regulators are important for inoculated fermentation of Chinese sesame-flavored liquor. PMID:24814798

  5. Influence of the Tumor Microenvironment on Cancer Cells Metabolic Reprogramming

    Victoire Gouirand

    2018-04-01

    Full Text Available As with castles, tumor cells are fortified by surrounding non-malignant cells, such as cancer-associated fibroblasts, immune cells, but also nerve fibers and extracellular matrix. In most cancers, this fortification creates a considerable solid pressure which limits oxygen and nutrient delivery to the tumor cells and causes a hypoxic and nutritional stress. Consequently, tumor cells have to adapt their metabolism to survive and proliferate in this harsh microenvironment. To satisfy their need in energy and biomass, tumor cells develop new capacities to benefit from metabolites of the microenvironment, either by their uptake through the macropinocytosis process or through metabolite transporters, or by a cross-talk with stromal cells and capture of extracellular vesicles that are released by the neighboring cells. However, the microenvironments of primary tumor and metastatic niches differ tremendously in their cellular/acellular components and available nutrients. Therefore, cancer cells must develop a metabolic flexibility conferring on them the ability to satisfy their biomass and energetic demands at both primary and metastasis sites. In this review, we propose a brief overview of how proliferating cancer cells take advantage of their surrounding microenvironment to satisfy their high metabolic demand at both primary and metastasis sites.

  6. MicroScope—an integrated microbial resource for the curation and comparative analysis of genomic and metabolic data

    Vallenet, David; Belda, Eugeni; Calteau, Alexandra; Cruveiller, Stéphane; Engelen, Stefan; Lajus, Aurélie; Le Fèvre, François; Longin, Cyrille; Mornico, Damien; Roche, David; Rouy, Zoé; Salvignol, Gregory; Scarpelli, Claude; Thil Smith, Adam Alexander; Weiman, Marion; Médigue, Claudine

    2013-01-01

    MicroScope is an integrated platform dedicated to both the methodical updating of microbial genome annotation and to comparative analysis. The resource provides data from completed and ongoing genome projects (automatic and expert annotations), together with data sources from post-genomic experiments (i.e. transcriptomics, mutant collections) allowing users to perfect and improve the understanding of gene functions. MicroScope (http://www.genoscope.cns.fr/agc/microscope) combines tools and graphical interfaces to analyse genomes and to perform the manual curation of gene annotations in a comparative context. Since its first publication in January 2006, the system (previously named MaGe for Magnifying Genomes) has been continuously extended both in terms of data content and analysis tools. The last update of MicroScope was published in 2009 in the Database journal. Today, the resource contains data for >1600 microbial genomes, of which ∼300 are manually curated and maintained by biologists (1200 personal accounts today). Expert annotations are continuously gathered in the MicroScope database (∼50 000 a year), contributing to the improvement of the quality of microbial genomes annotations. Improved data browsing and searching tools have been added, original tools useful in the context of expert annotation have been developed and integrated and the website has been significantly redesigned to be more user-friendly. Furthermore, in the context of the European project Microme (Framework Program 7 Collaborative Project), MicroScope is becoming a resource providing for the curation and analysis of both genomic and metabolic data. An increasing number of projects are related to the study of environmental bacterial (meta)genomes that are able to metabolize a large variety of chemical compounds that may be of high industrial interest. PMID:23193269

  7. Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

    Lin, Xiaoxi B.; Gänzle, Michael G.

    2014-01-01

    This study determined the effects of specific metabolic traits of Lactobacillus reuteri on its competitiveness in sourdoughs. The competitiveness of lactobacilli in sourdough generally depends on their growth rate; acid resistance additionally contributes to competitiveness in sourdoughs with long fermentation times. Glycerol metabolism via glycerol dehydratase (gupCDE) accelerates growth by the regeneration of reduced cofactors; glutamate metabolism via glutamate decarboxylase (gadB) increas...

  8. Application of Stable Isotope-Assisted Metabolomics for Cell Metabolism Studies

    You, Le; Zhang, Baichen; Tang, Yinjie J.

    2014-01-01

    The applications of stable isotopes in metabolomics have facilitated the study of cell metabolisms. Stable isotope-assisted metabolomics requires: (1) properly designed tracer experiments; (2) stringent sampling and quenching protocols to minimize isotopic alternations; (3) efficient metabolite separations; (4) high resolution mass spectrometry to resolve overlapping peaks and background noises; and (5) data analysis methods and databases to decipher isotopic clusters over a broad m/z range (mass-to-charge ratio). This paper overviews mass spectrometry based techniques for precise determination of metabolites and their isotopologues. It also discusses applications of isotopic approaches to track substrate utilization, identify unknown metabolites and their chemical formulas, measure metabolite concentrations, determine putative metabolic pathways, and investigate microbial community populations and their carbon assimilation patterns. In addition, 13C-metabolite fingerprinting and metabolic models can be integrated to quantify carbon fluxes (enzyme reaction rates). The fluxome, in combination with other “omics” analyses, may give systems-level insights into regulatory mechanisms underlying gene functions. More importantly, 13C-tracer experiments significantly improve the potential of low-resolution gas chromatography-mass spectrometry (GC-MS) for broad-scope metabolism studies. We foresee the isotope-assisted metabolomics to be an indispensable tool in industrial biotechnology, environmental microbiology, and medical research. PMID:24957020

  9. Cell signalling and phospholipid metabolism. Final report

    Boss, W.F.

    1990-12-31

    These studies explored whether phosphoinositide (PI) has a role in plants analogous to its role in animal cells. Although no parallel activity of PI in signal transduction was found in plant cells, activity of inositol phospholipid kinase was found to be modulated by light and by cell wall degrading enzymes. These studies indicate a major role for inositol phospholipids in plant growth and development as membrane effectors but not as a source of second messengers.

  10. Marked Response in Microbial Community and Metabolism in the Ileum and Cecum of Suckling Piglets After Early Antibiotics Exposure

    Miao Yu

    2018-05-01

    Full Text Available In modern swine husbandry systems, antibiotics have been used as growth promoters for piglets during suckling or weaning period. However, while early colonization of intestinal microbiota has been regarded crucial for the host’s later life performance and well-being, little is known about the impact of antibiotics on intestinal microbiota in suckling piglets. The present study aimed to investigate the effects of early antibiotics exposure on gut microbiota and microbial metabolism of suckling piglets. Sixteen litters of suckling piglets were fed a creep feed diet with (Antibiotic or without (Control antibiotics from postnatal days 7–23 (n = 8. The ileal and cecal digesta were obtained for microbial composition and microbial metabolites analysis. The results showed that the antibiotics significantly altered the bacterial community composition by decreasing (P < 0.05 the diversity and richness in the ileum. The antibiotics significantly reduced the abundance of Lactobacillus in both the ileum and cecum, increased the abundance of Streptococcus, unclassified Enterococcaceae, unclassified Fusobacteriales, and Corynebacterium in the ileum, and the abundance of unclassified Ruminococcaceae and unclassified Erysipelotrichaceae in the cecum. The antibiotics decreased (P < 0.05 ileal lactate concentration and cecal concentration of total short-chain fatty acids (SCFAs. But the antibiotics enhanced protein fermentation (P < 0.05 in the ileum and cecum, as ileal concentrations of putrescine and cadaverine, and cecal concentrations of isobutyrate, isovalerate, putrescine, cadaverine, spermine, and spermidine were significantly increased (P < 0.05. These results indicated that early antibiotics exposure significantly altered the microbial composition of suckling piglets toward a vulnerable and unhealthy gut environment. The findings provide a new insight on the antibiotics impact on neonates and may provide new framework for designing alternatives to the

  11. Microbial metabolism and community structure in response to bioelectrochemically enhanced remediation of petroleum hydrocarbon-contaminated soil.

    Lu, Lu; Huggins, Tyler; Jin, Song; Zuo, Yi; Ren, Zhiyong Jason

    2014-04-01

    This study demonstrates that electrodes in a bioelectrochemical system (BES) can potentially serve as a nonexhaustible electron acceptor for in situ bioremediation of hydrocarbon contaminated soil. The deployment of BES not only eliminates aeration or supplement of electron acceptors as in contemporary bioremediation but also significantly shortens the remediation period and produces sustainable electricity. More interestingly, the study reveals that microbial metabolism and community structure distinctively respond to the bioelectrochemically enhanced remediation. Tubular BESs with carbon cloth anode (CCA) or biochar anode (BCA) were inserted into raw water saturated soils containing petroleum hydrocarbons for enhancing in situ remediation. Results show that total petroleum hydrocarbon (TPH) removal rate almost doubled in soils close to the anode (63.5-78.7%) than that in the open circuit positive controls (37.6-43.4%) during a period of 64 days. The maximum current density from the BESs ranged from 73 to 86 mA/m(2). Comprehensive microbial and chemical characterizations and statistical analyses show that the residual TPH has a strongly positive correlation with hydrocarbon-degrading microorganisms (HDM) numbers, dehydrogenase activity, and lipase activity and a negative correlation with soil pH, conductivity, and catalase activity. Distinctive microbial communities were identified at the anode, in soil with electrodes, and soil without electrodes. Uncommon electrochemically active bacteria capable of hydrocarbon degradation such as Comamonas testosteroni, Pseudomonas putida, and Ochrobactrum anthropi were selectively enriched on the anode, while hydrocarbon oxidizing bacteria were dominant in soil samples. Results from genus or phylum level characterizations well agree with the data from cluster analysis. Data from this study suggests that a unique constitution of microbial communities may play a key role in BES enhancement of petroleum hydrocarbons

  12. Bacillus licheniformis affects the microbial community and metabolic profile in the spontaneous fermentation of Daqu starter for Chinese liquor making.

    Wang, Peng; Wu, Qun; Jiang, Xuejian; Wang, Zhiqiang; Tang, Jingli; Xu, Yan

    2017-06-05

    Chinese liquor is produced from spontaneous fermentation starter (Daqu) that provides the microbes, enzymes and flavors for liquor fermentation. To improve the flavor character of Daqu, we inoculated Bacillus licheniformis and studied the effect of this strain on the community structure and metabolic profile in Daqu fermentation. The microbial relative abundance changed after the inoculation, including the increase in Bacillus, Clavispora and Aspergillus, and the decrease in Pichia, Saccharomycopsis and some other genera. This variation was also confirmed by pure culture and coculture experiments. Seventy-three metabolites were identified during Daqu fermentation process. After inoculation, the average content of aromatic compounds were significantly enriched from 0.37mg/kg to 0.90mg/kg, and the average content of pyrazines significantly increased from 0.35mg/kg to 5.71mg/kg. The increase in pyrazines was positively associated with the metabolism of the inoculated Bacillus and the native genus Clavispora, because they produced much more pyrazines in their cocultures. Whereas the increase in aromatic compounds might be related to the change of in situ metabolic activity of several native genera, in particular, Aspergillus produced more aromatic compounds in cocultures with B. licheniformis. It indicated that the inoculation of B. licheniformis altered the flavor character of Daqu by both its own metabolic activity and the variation of in situ metabolic activity. Moreover, B. licheniformis inoculation influenced the enzyme activity of Daqu, including the significant increase in amylase activity (from 1.3gstarch/g/h to 1.7gstarch/g/h), and the significant decrease in glucoamylase activity (from 627.6mgglucose/g/h to 445.6mgglucose/g/h) and esterase activity (from 28.1mgethylcaproate/g/100h to 17.2mgethylcaproate/g/100h). These effects of inoculation were important factors for regulating the metabolism of microbial communities, hence for improving the flavor profile

  13. Set anode potentials affect the electron fluxes and microbial community structure in propionate-fed microbial electrolysis cells

    Rao, Hari Ananda

    2016-12-09

    Anode potential has been shown to be a critical factor in the rate of acetate removal in microbial electrolysis cells (MECs), but studies with fermentable substrates and set potentials are lacking. Here, we examined the impact of three different set anode potentials (SAPs; −0.25, 0, and 0.25 V vs. standard hydrogen electrode) on the electrochemical performance, electron flux to various sinks, and anodic microbial community structure in two-chambered MECs fed with propionate. Electrical current (49–71%) and CH4 (22.9–41%) were the largest electron sinks regardless of the potentials tested. Among the three SAPs tested, 0 V showed the highest electron flux to electrical current (71 ± 5%) and the lowest flux to CH4 (22.9 ± 1.2%). In contrast, the SAP of −0.25 V had the lowest electron flux to current (49 ± 6%) and the highest flux to CH4 (41.1 ± 2%). The most dominant genera detected on the anode of all three SAPs based on 16S rRNA gene sequencing were Geobacter, Smithella and Syntrophobacter, but their relative abundance varied among the tested SAPs. Microbial community analysis implies that complete degradation of propionate in all the tested SAPs was facilitated by syntrophic interactions between fermenters and Geobacter at the anode and ferementers and hydrogenotrophic methanogens in suspension.

  14. Comparative Metagenomic Analysis of Electrogenic Microbial Communities in Differentially Inoculated Swine Wastewater-Fed Microbial Fuel Cells

    Irina V. Khilyas

    2017-01-01

    Full Text Available 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. Using a metagenomic approach, we describe the microbial diversity of the MFC planktonic and anodic communities derived from the different inocula. Proteobacteria (mostly Deltaproteobacteria became the predominant phylum in both MFC anodic communities with amplification of the electrogenic genus Geobacter being the most pronounced. Eight dominant and three minor species of Geobacter were found in both MFC anodic communities. The anodic communities of the SS-inoculated MFCs had a higher proportion of Clostridium and Bacteroides relative to those of the IGBS-inoculated MFCs, which were enriched with Pelobacter. The archaeal populations of the SS- and IGBS-inoculated MFCs were dominated by Methanosarcina barkeri and Methanothermobacter thermautotrophicus, respectively. Our results show a long-term influence of inoculum type on the performance and microbial community composition of swine wastewater-treating MFCs.

  15. Series Assembly of Microbial Desalination Cells Containing Stacked Electrodialysis Cells for Partial or Complete Seawater Desalination

    Kim, Younggy

    2011-07-01

    A microbial desalination cell (MDC) is a new approach for desalinating water based on using the electrical current generated by exoelectrogenic bacteria. Previously developed MDCs have used only one or two desalination chambers with substantial internal resistance, and used low salinity catholytes containing a buffered or acid solution. Here we show that substantially improved MDC performance can be obtained even with a nonbuffered, saline catholyte, by using an electrodialysis stack consisting of 5 pairs of desalting and concentrating cells. When 4 stacked MDCs were used in series (20 total pairs of desalination chambers), the salinity of 0.06 L of synthetic seawater (35 g/L NaCl) was reduced by 44% using 0.12 L of anode solution (2:1). The resistive loss in the electrodialysis stack was negligible due to minimization of the intermembrane distances, and therefore the power densities produced by the MDC were similar to those produced by single chamber microbial fuel cells (MFCs) lacking desalination chambers. The observed current efficiency was 86%, indicating separation of 4.3 pairs of sodium and chloride ions for every electron transferred through the circuit. With two additional stages (total of 3.8 L of anolyte), desalination was increased to 98% salt removal, producing 0.3 L of fresh water (12.6:1). These results demonstrate that stacked MDCs can be used for efficient desalination of seawater while at the same time achieving power densities comparable to those obtained in MFCs. © 2011 American Chemical Society.

  16. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone

    2017-01-01

    . In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic...... efforts, depend largely on the oxygenation history of sites. Furthermore, it was shown that re-oxygenation efforts to remediate dead zones could ultimately be facilitated by in situ microbial molecular mechanisms involved in removal of toxic H2S and the potent greenhouse gas methane....

  17. Salt removal using multiple microbial desalination cells under continuous flow conditions

    Qu, Youpeng

    2013-05-01

    Four microbial desalination cells (MDCs) were hydraulically connected and operated under continuous flow conditions. The anode solution from the first MDC flowed into the cathode, and then on to the anode of the next reactor, which avoided pH imbalances that inhibit bacterial metabolism. The salt solution also moved through each desalination chamber in series. Increasing the hydraulic retention times (HRTs) of the salt solution from 1 to 2. days increased total NaCl removal from 76 ± 1% to 97 ± 1%, but coulombic efficiencies decreased from 49 ± 4% to 35 ± 1%. Total COD removals were similar at both HRTs (60 ± 2%, 2. days; 59 ± 2%, 1. day). Community analysis of the anode biofilms showed that bacteria most similar to the xylose fermenting bacterium Klebsiella ornithinolytica predominated in the anode communities, and sequences most similar to Geobacter metallireducens were identified in all MDCs except the first one. These results demonstrated successful operation of a series of hydraulically connected MDCs and good desalination rates. © 2013 Elsevier B.V..

  18. Metabolic adaptations of Azospirillum brasilense to oxygen stress by cell-to-cell clumping and flocculation.

    Bible, Amber N; Khalsa-Moyers, Gurusahai K; Mukherjee, Tanmoy; Green, Calvin S; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Hurst, Gregory B; Alexandre, Gladys

    2015-12-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  19. Microbial electrolysis cells turning to be versatile technology: recent advances and future challenges

    Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    and achieve high-yield hydrogen production from wide range of organic matters at relatively mild conditions. This approach greatly reduces the electric energy cost for hydrogen production in contrast to direct water electrolysis. In addition to hydrogen production, MECs may also support several energetically......Microbial electrolysis cells (MECs) are an electricity-mediated microbial bioelectrochemical technology, which is originally developed for high-efficiency biological hydrogen production from waste streams. Compared to traditional biological technologies, MECs can overcome thermodynamic limitations...

  20. Metabolism of murine TH 17 cells: Impact on cell fate and function.

    Wang, Ran; Solt, Laura A

    2016-04-01

    An effective adaptive immune response relies on the ability of lymphocytes to rapidly act upon a variety of insults. In T lymphocytes, this response includes cell growth, clonal expansion, differentiation, and cytokine production, all of which place a significant energy burden on the cell. Recent evidence shows that T-cell metabolic reprogramming is an essential component of the adaptive immune response and specific metabolic pathways dictate T-cell fate decisions, including the development of TH 17 versus T regulatory (Treg) cells. TH 17 cells have garnered significant attention due to their roles in the pathology of immune-mediated inflammatory diseases. Attempts to characterize TH 17 cells have demonstrated that they are highly dynamic, adjusting their function to environmental cues, which dictate their metabolic program. In this review, we highlight recent data demonstrating the impact of cellular metabolism on the TH 17/Treg balance and present factors that mediate TH 17-cell metabolism. Some examples of these include the differential impact of the mTOR signaling complexes on T-helper-cell differentiation, hypoxia inducible factor 1 alpha (HIF1α) promotion of glycolysis to favor TH 17-cell development, and ACC1-dependent de novo fatty acid synthesis favoring TH 17-cell development over Treg cells. Finally, we discuss the potential therapeutic options and the implications of modulating TH 17-cell metabolism for the treatment of TH 17-mediated diseases. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. SYSTEMS BIOLOGY AND METABOLIC ENGINEERING OF ARTHROSPIRA CELL FACTORIES

    Amornpan Klanchui

    2012-10-01

    Full Text Available Arthrospira are attractive candidates to serve as cell factories for production of many valuable compounds useful for food, feed, fuel and pharmaceutical industries. In connection with the development of sustainable bioprocessing, it is a challenge to design and develop efficient Arthrospira cell factories which can certify effective conversion from the raw materials (i.e. CO2 and sun light into desired products. With the current availability of the genome sequences and metabolic models of Arthrospira, the development of Arthrospira factories can now be accelerated by means of systems biology and the metabolic engineering approach. Here, we review recent research involving the use of Arthrospira cell factories for industrial applications, as well as the exploitation of systems biology and the metabolic engineering approach for studying Arthrospira. The current status of genomics and proteomics through the development of the genome-scale metabolic model of Arthrospira, as well as the use of mathematical modeling to simulate the phenotypes resulting from the different metabolic engineering strategies are discussed. At the end, the perspective and future direction on Arthrospira cell factories for industrial biotechnology are presented.

  2. Natural Compounds as Regulators of the Cancer Cell Metabolism

    Claudia Cerella

    2013-01-01

    Full Text Available Even though altered metabolism is an “old” physiological mechanism, only recently its targeting became a therapeutically interesting strategy and by now it is considered an emerging hallmark of cancer. Nevertheless, a very poor number of compounds are under investigation as potential modulators of cell metabolism. Candidate agents should display selectivity of action towards cancer cells without side effects. This ideal favorable profile would perfectly overlap the requisites of new anticancer therapies and chemopreventive strategies as well. Nature represents a still largely unexplored source of bioactive molecules with a therapeutic potential. Many of these compounds have already been characterized for their multiple anticancer activities. Many of them are absorbed with the diet and therefore possess a known profile in terms of tolerability and bioavailability compared to newly synthetized chemical compounds. The discovery of important cross-talks between mediators of the most therapeutically targeted aberrancies in cancer (i.e., cell proliferation, survival, and migration and the metabolic machinery allows to predict the possibility that many anticancer activities ascribed to a number of natural compounds may be due, in part, to their ability of modulating metabolic pathways. In this review, we attempt an overview of what is currently known about the potential of natural compounds as modulators of cancer cell metabolism.

  3. Minimal RED Cell Pairs Markedly Improve Electrode Kinetics and Power Production in Microbial Reverse Electrodialysis Cells

    Cusick, Roland D.

    2013-12-17

    Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m 2-cat) and wastewater (WW: 0.3 to 1.7 W/m2), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m2; WW: 1.9 W/m2). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m2-mem; WW: 1.7 W/m2) and 2-CP (Acetate: 1.3 W/m2-mem; WW: 0.6 W/m2) reactors were much higher than previous MRCs (0.3-0.5 W/m2-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment. © 2013 American Chemical Society.

  4. Minimal RED Cell Pairs Markedly Improve Electrode Kinetics and Power Production in Microbial Reverse Electrodialysis Cells

    Cusick, Roland D.; Hatzell, Marta; Zhang, Fang; Logan, Bruce E.

    2013-01-01

    Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m 2-cat) and wastewater (WW: 0.3 to 1.7 W/m2), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m2; WW: 1.9 W/m2). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m2-mem; WW: 1.7 W/m2) and 2-CP (Acetate: 1.3 W/m2-mem; WW: 0.6 W/m2) reactors were much higher than previous MRCs (0.3-0.5 W/m2-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment. © 2013 American Chemical Society.

  5. Separator Characteristics for Increasing Performance of Microbial Fuel Cells

    Zhang, Xiaoyuan

    2009-11-01

    Two challenges for improving the performance of air cathode, single-chamber microbial fuel cells (MFCs) include increasing Coulombic efficiency (CE) and decreasing internal resistance. Nonbiodegradable glass fiber separators between the two electrodes were shown to increase power and CE, compared to cloth separators (J-cloth) that were degraded over time. MFCtestswereconductedusing glass fibermatswith thicknesses of 1.0mm (GF1) or 0.4 mm (GF0.4), a cation exchange membrane (CEM), and a J-cloth (JC), using reactors with different configurations. Higher power densities were obtained with either GF1 (46 ± 4 W/m3) or JC (46 ± 1 W/m3) in MFCs with a 2 cm electrode spacing, when the separator was placed against the cathode (S-configuration), rather than MFCs with GF0.4 (36 ± 1 W/m3) or CEM (14 ± 1 W/m3). Power was increased to 70 ± 2 W/m3 by placing the electrodes on either side of the GF1 separator (single separator electrode assembly, SSEA) and further to 150 ± 6 W/m3 using two sets of electrodes spaced 2 cm a part (double separator electrode assembly, DSEA). Reducing the DSEA electrode spacing to 0.3 cm increased power to 696 ± 26 W/m3 as a result of a decrease in the ohmic resistance from 5.9 to 2.2 Ω. The main advantages of a GF1 separator compared to JC were an improvement in the CE from 40% to 81% (S-configuration), compared to only 20-40% for JC under similar conditions, and the fact that GF1 was not biodegradable. The high CE for the GF1 separator was attributed to a low oxygen mass transfer coefficient (ko ) 5.0 x 10-5 cm/s). The GF1 andJCmaterials differed in the amount of biomass that accumulated on the separator and its biodegradability, which affected long-term power production and oxygen transport. These results show that materials and mass transfer properties of separators are important factors for improving power densities, CE, and long-term performance of MFCs. © 2009 American Chemical Society.

  6. Cationic fluorinated polymer binders for microbial fuel cell cathodes

    Chen, Guang; Wei, Bin; Logan, Bruce E.; Hickner, Michael A.

    2012-01-01

    Fluorinated quaternary ammonium-containing polymers were used as catalyst binders in microbial fuel cell (MFC) cathodes. The performance of the cathodes was examined and compared to NAFION ® and other sulfonated aromatic cathode catalyst binders using linear sweep voltammetry (LSV), impedance spectroscopy, and performance tests in single chamber air-cathode MFCs. The cathodes with quaternary ammonium functionalized fluorinated poly(arylene ether) (Q-FPAE) binders showed similar current density and charge transfer resistance (R ct) to cathodes with NAFION ® binders. Cathodes containing either of these fluorinated binders exhibited better electrochemical responses than cathodes with sulfonated or quaternary ammonium-functionalized RADEL ® poly(sulfone) (S-Radel or Q-Radel) binders. After 19 cycles (19 d), the power densities of all the MFCs declined compared to the initial cycles due to biofouling at the cathode. MFC cathodes with fluorinated polymer binders (1445 mW m -2, Q-FPAE-1.4-H; 1397 mW m -2, Q-FPAE-1.4-Cl; 1277 mW m -2, NAFION ®; and 1256 mW m -2, Q-FPAE-1.0-Cl) had better performance than those with non-fluorinated polymer binders (880 mW m -2, S-Radel; 670 mW m -2, Q-Radel). There was a 15% increase in the power density using the Q-FPAE binder with a 40% higher ion exchange capacity (Q-FPAE-1.4-H compared to Q-FPAE-1.0-Cl) after 19 cycles of operation, but there was no effect on the power production due to counter ions in the binder (Cl -vs. HCO 3 -). The highest-performance cathodes (NAFION ® and Q-FPAE binders) had the lowest charge transfer resistances (R ct) in fresh and in fouled cathodes despite the presence of thick biofilms on the surface of the electrodes. These results show that fluorinated binders may decrease the penetration of the biofilm and associated biopolymers into the cathode structure, which helps to combat MFC performance loss over time. © 2012 The Royal Society of Chemistry.

  7. Modular spectral imaging system for discrimination of pigments in cells and microbial communities.

    Polerecky, Lubos; Bissett, Andrew; Al-Najjar, Mohammad; Faerber, Paul; Osmers, Harald; Suci, Peter A; Stoodley, Paul; de Beer, Dirk

    2009-02-01

    Here we describe a spectral imaging system for minimally invasive identification, localization, and relative quantification of pigments in cells and microbial communities. The modularity of the system allows pigment detection on spatial scales ranging from the single-cell level to regions whose areas are several tens of square centimeters. For pigment identification in vivo absorption and/or autofluorescence spectra are used as the analytical signals. Along with the hardware, which is easy to transport and simple to assemble and allows rapid measurement, we describe newly developed software that allows highly sensitive and pigment-specific analyses of the hyperspectral data. We also propose and describe a number of applications of the system for microbial ecology, including identification of pigments in living cells and high-spatial-resolution imaging of pigments and the associated phototrophic groups in complex microbial communities, such as photosynthetic endolithic biofilms, microbial mats, and intertidal sediments. This system provides new possibilities for studying the role of spatial organization of microorganisms in the ecological functioning of complex benthic microbial communities or for noninvasively monitoring changes in the spatial organization and/or composition of a microbial community in response to changing environmental factors.

  8. A Consensus Genome-scale Reconstruction of Chinese Hamster Ovary Cell Metabolism

    Hefzi, Hooman; Ang, Kok Siong; Hanscho, Michael

    2016-01-01

    Chinese hamster ovary (CHO) cells dominate biotherapeutic protein production and are widely used in mammalian cell line engineering research. To elucidate metabolic bottlenecks in protein production and to guide cell engineering and bioprocess optimization, we reconstructed the metabolic pathways...

  9. Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation

    Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

    2017-01-01

    Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food

  10. Immobilization of microbial cells: A promising tool for treatment of ...

    Suzana

    2013-07-10

    Jul 10, 2013 ... (zeolite, clay, anthracite, porous glass, activated char- coal, and ceramics) and organic polymers. Inorganic carriers were selected to immobilize microorganisms because they can resist microbial degradation and are thermostable (Cassidy et al., 1996; Verma et al., 2006). The organic polymeric carriers are ...

  11. Microbial Metabolism. Part 10. Metabolites of 7,8 Dimethoxyflavone and 5-Methoxyflavone

    Microbial transformation of 7, 8-dimethoxyflavone (1) by Mucor ramannianus (ATCC 9628) produced five metabolites: 7, 8-dimethoxy-4'-hydroxyflavone (2), 3', 4'-dihydroxy-7, 8-dimethoxyflavone (3), 7, 3'-dihydroxy-8-methoxyflavone (4), 7, 4'-dihydroxy-8-methoxyflavone (5) and 8-methoxy-7, 3', 4'-trihy...

  12. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    1987-01-01

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells. (author)

  13. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

  14. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2...

  15. Choosing the right platform for the right product: Sustainable production of chemicals in microbial cell factories

    Herrgard, Markus

    The Novo Nordisk Foundation Center for Biosustainability (CFB) is a new non-profit research center focused on sustainable production of biochemicals and therapeutic proteins using microbial and mammalian cell factories. The work at CFB is organized around an iterative loop where cell factories...

  16. Frozen in Time? Microbial strategies for survival and carbon metabolism over geologic time in a Pleistocene permafrost chronosequence

    Mackelprang, R.; Douglas, T. A.; Waldrop, M. P.

    2014-12-01

    Permafrost soils have received tremendous interest due to their importance as a global carbon store with the potential to be thawed over the coming centuries. Instead of being 'frozen in time,' permafrost contains active microbes. Most metagenomic studies have focused on Holocene aged permafrost. Here, we target Pleistocene aged ice and carbon rich permafrost (Yedoma), which can differ in carbon content and stage of decay. Our aim was to understand how microbes in the permafrost transform organic matter over geologic time and to identify physiological and biochemical adaptations that enable long-term survival. We used next-generation sequencing to characterize microbial communities along a permafrost age gradient. Samples were collected from the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel near Fox, AK, which penetrates a hillside providing access to permafrost ranging in age from 12 to 40 kyr. DNA was extracted directly from unthawed samples. 16S rRNA amplicon (16S) and shotgun metagenome sequencing revealed significant age-driven differences. First, microbial diversity declines with permafrost age, likely due to long-term exposure to environmental stresses and a reduction in metabolic resources. Second, we observed taxonomic differences among ages, with an increasing abundance of Firmicutes (endospore-formers) in older samples, suggesting that dormancy is a common survival strategy in older permafrost. Ordination of 16S and metagenome data revealed age-based clustering. Genes differing significantly between age categories included those involved in lipopolysaccharide assembly, cold-response, and carbon processing. These data point to the physiological adaptations to long-term frozen conditions and to the metabolic processes utilized in ancient permafrost. In fact, a gene common in older samples is involved in cadaverine production, which could potentially explain the putrefied smell of Pleistocene aged permafrost. Coupled with soil

  17. Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion.

    Sousa, Cristovão M; Biancur, Douglas E; Wang, Xiaoxu; Halbrook, Christopher J; Sherman, Mara H; Zhang, Li; Kremer, Daniel; Hwang, Rosa F; Witkiewicz, Agnes K; Ying, Haoqiang; Asara, John M; Evans, Ronald M; Cantley, Lewis C; Lyssiotis, Costas A; Kimmelman, Alec C

    2016-08-25

    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by an intense fibrotic stromal response and deregulated metabolism. The role of the stroma in PDAC biology is complex and it has been shown to play critical roles that differ depending on the biological context. The stromal reaction also impairs the vasculature, leading to a highly hypoxic, nutrient-poor environment. As such, these tumours must alter how they capture and use nutrients to support their metabolic needs. Here we show that stroma-associated pancreatic stellate cells (PSCs) are critical for PDAC metabolism through the secretion of non-essential amino acids (NEAA). Specifically, we uncover a previously undescribed role for alanine, which outcompetes glucose and glutamine-derived carbon in PDAC to fuel the tricarboxylic acid (TCA) cycle, and thus NEAA and lipid biosynthesis. This shift in fuel source decreases the tumour’s dependence on glucose and serum-derived nutrients, which are limited in the pancreatic tumour microenvironment. Moreover, we demonstrate that alanine secretion by PSCs is dependent on PSC autophagy, a process that is stimulated by cancer cells. Thus, our results demonstrate a novel metabolic interaction between PSCs and cancer cells, in which PSC-derived alanine acts as an alternative carbon source. This finding highlights a previously unappreciated metabolic network within pancreatic tumours in which diverse fuel sources are used to promote growth in an austere tumour microenvironment.

  18. Performance of Microbial Fuel Cell for Wastewater Treatment and Electricity Generation

    Z Yavari

    2013-06-01

    Full Text Available Renewable energy will have an important role as a resource of energy in the future. Microbial fuel cell (MFC is a promising method to obtain electricity from organic matter andwastewater treatment simultaneously. In a pilot study, use of microbial fuel cell for wastewater treatment and electricity generation investigated. The bacteria of ruminant used as inoculums. Synthetic wastewater used at different organic loading rate. Hydraulic retention time was aneffective factor in removal of soluble COD and more than 49% removed. Optimized HRT to achieve the maximum removal efficiency and sustainable operation could be regarded 1.5 and 2.5 hours. Columbic efficiency (CE affected by organic loading rate (OLR and by increasing OLR, CE reduced from 71% to 8%. Maximum voltage was 700mV. Since the microbial fuel cell reactor considered as an anaerobic process, it may be an appropriate alternative for wastewater treatment

  19. Are pathogenic bacteria just looking for food? Metabolism and microbial pathogenesis

    Rohmer, Laurence; Hocquet, Didier; Miller, Samuel I.

    2011-01-01

    It is interesting to speculate that the evolutionary drive of microbes to develop pathogenic characteristics was to access the nutrient resources that animals provided. Environments in animals that pathogens colonize have also driven the evolution of new bacterial characteristics to maximize these new nutritional opportunities. This review focuses on genomic and functional aspects of pathogen metabolism that allow efficient utilization of nutrient resources provided by animals. Similar to genes encoding specific virulence traits, some genes encoding metabolic functions have been horizontally acquired by pathogens to provide a selective advantage in host tissues. Selective advantage in host tissues can also be gained in some circumstances by loss of function due to mutations that alter metabolic capabilities. Greater understanding of bacterial metabolism within host tissues should be important for increased understanding of host-pathogen interactions and the development of future therapeutic strategies. PMID:21600774

  20. Influence of Wastewater Discharge on the Metabolic Potential of the Microbial Community in River Sediments

    Li, Dong; Sharp, Jonathan O.; Drewes, Jorg

    2015-01-01

    , sulfur, purine and pyrimidine metabolisms, as well as restriction–modification systems. More diverse bacterial phyla were associated with upstream and deep downstream sediments, mainly including Actinobacteria, Planctomycetes, and Firmicutes. In contrast

  1. Natural Killer Cell Activity and Interleukin-12 in Metabolically Healthy versus Metabolically Unhealthy Overweight Individuals

    Kim, Minjoo; Kim, Minkyung; Yoo, Hye Jin; Lee, Jong Ho

    2017-01-01

    The purpose of this study was to determine whether the immune system is involved in the different metabolic circumstances in healthy and unhealthy overweight individuals. We examined the metabolic and immune characteristics of 117 overweight individuals. Subjects were classified as metabolically healthy overweight (MHO, n = 72) or metabolically unhealthy overweight (MUO, n = 45). The immune response was measured by circulating levels of natural killer (NK) cell activity and cytokines. Both groups were comparable with regards to age, sex distribution, smoking and drinking status, and body mass index. When compared to the MHO group, the MUO group showed higher systolic and diastolic blood pressure, serum levels of triglyceride, glucose, glucose-related markers, and lower levels of HDL cholesterol. Compared to the MHO group, the MUO group showed 39% lower interferon-γ levels (not significant) and 41% lower interleukin (IL)-12 levels (significant). The MUO group also showed lower NK cell activity at E:T ratios of 10:1, 5:1, 2.5:1, and 1.25:1 (all Ps < 0.05) than the MHO group. This study indicates that individuals displaying the MUO phenotype present an unfavorable immune system with lower NK cell activities under all assay conditions and lower serum levels of IL-12 than the activities and levels in similarly overweight MHO individuals. This result suggests that the immune system may be altered in overweight individuals who are at risk for overweight/obesity-related comorbidities. PMID:29238351

  2. Natural Killer Cell Activity and Interleukin-12 in Metabolically Healthy versus Metabolically Unhealthy Overweight Individuals

    Minjoo Kim

    2017-11-01

    Full Text Available The purpose of this study was to determine whether the immune system is involved in the different metabolic circumstances in healthy and unhealthy overweight individuals. We examined the metabolic and immune characteristics of 117 overweight individuals. Subjects were classified as metabolically healthy overweight (MHO, n = 72 or metabolically unhealthy overweight (MUO, n = 45. The immune response was measured by circulating levels of natural killer (NK cell activity and cytokines. Both groups were comparable with regards to age, sex distribution, smoking and drinking status, and body mass index. When compared to the MHO group, the MUO group showed higher systolic and diastolic blood pressure, serum levels of triglyceride, glucose, glucose-related markers, and lower levels of HDL cholesterol. Compared to the MHO group, the MUO group showed 39% lower interferon-γ levels (not significant and 41% lower interleukin (IL-12 levels (significant. The MUO group also showed lower NK cell activity at E:T ratios of 10:1, 5:1, 2.5:1, and 1.25:1 (all Ps < 0.05 than the MHO group. This study indicates that individuals displaying the MUO phenotype present an unfavorable immune system with lower NK cell activities under all assay conditions and lower serum levels of IL-12 than the activities and levels in similarly overweight MHO individuals. This result suggests that the immune system may be altered in overweight individuals who are at risk for overweight/obesity-related comorbidities.

  3. Metabolic behavior of cell surface biotinylated proteins

    Hare, J.F.; Lee, E.

    1989-01-01

    The turnover of proteins on the surface of cultured mammalian cells was measured by a new approach. Reactive free amino or sulfhydryl groups on surface-accessible proteins were derivatized with biotinyl reagents and the proteins solubilized from culture dishes with detergent. Solubilized, biotinylated proteins were then adsorbed onto streptavidin-agarose, released with sodium dodecyl sulfate and mercaptoethanol, and separated on polyacrylamide gels. Biotin-epsilon-aminocaproic acid N-hydroxysuccinimide ester (BNHS) or N-biotinoyl-N'-(maleimidohexanoyl)hydrazine (BM) were the derivatizing agents. Only 10-12 bands were adsorbed onto streptavidin-agarose from undervatized cells or from derivatized cells treated with free avidin at 4 degrees C. Two-dimensional isoelectric focusing-sodium dodecyl sulfate gel electrophoresis resolved greater than 100 BNHS-derivatized proteins and greater than 40 BM-derivatized proteins. There appeared to be little overlap between the two groups of derivatized proteins. Short-term pulse-chase studies showed an accumulation of label into both groups of biotinylated proteins up until 1-2 h of chase and a rapid decrease over the next 1-5 h. Delayed appearance of labeled protein at the cell surface was attributed to transit time from site of synthesis. The unexpected and unexplained rapid disappearance of pulse-labeled proteins from the cell surface was invariant for all two-dimensionally resolved proteins and was sensitive to temperature reduction to 18 degrees C. Long-term pulse-chase experiments beginning 4-8 h after the initiation of chase showed the disappearance of derivatized proteins to be a simple first-order process having a half-life of 115 h in the case of BNHS-derivatized proteins and 30 h in the case of BM-derivatized proteins

  4. Microbial food webs and metabolic state across oligotrophic waters of the Mediterranean Sea during summer

    U. Christaki

    2011-07-01

    Full Text Available The abundance and activity of the major members of the heterotrophic microbial community – from viruses to ciliates – were studied along a longitudinal transect across the Mediterranean Sea in the summer of 2008. The Mediterranean Sea is characterized by a west to-east gradient of deepening of DCM (deep chlorophyll maximum and increasing oligotrophy reflected in gradients of biomass and production. However, within this well documented longitudinal trend, hydrological mesoscale features exist and likely influence microbial dynamics. Here we present data from a W-E transect of 17 stations during the period of summer stratification. Along the transect the production and fate of organic matter was investigated at three selected sites each one located in the centre of an anticyclonic eddy: in the Algero-Provencal Basin (St. A, the Ionian Basin (St. B, and the Levantine Basin (St. C. The 3 geographically distant eddies showed low values of the different heterotrophic compartments of the microbial food web, and except for viruses in site C, all integrated (0–150 m stocks were higher in reference stations located in the same basin outside the eddies. During our study the 3 eddies showed equilibrium between GPP (Gross Primary Production and DCR (Dark Community Respiration. Integrated PPp (Particulate Primary Production values at A, B and C varied from ~140 to ~190 mg C m−2.

  5. Melatonin redirects carbohydrates metabolism during sugar starvation in plant cells.

    Kobylińska, Agnieszka; Borek, Sławomir; Posmyk, Małgorzata M

    2018-05-01

    Recent studies have shown that melatonin is an important molecule in plant physiology. It seems that the most important is that melatonin efficacy eliminates oxidative stress (direct and indirect antioxidant) and moreover induce plant stress reaction and switch on different defence strategies (preventively and interventively actions). In this report, the impact of exogenous melatonin on carbohydrate metabolism in Nicotiana tabacum L. line Bright Yellow 2 (BY-2) suspension cells during sugar starvation was examined. We analysed starch concentration, α-amylase and PEPCK activity as well as proteolytic activity in culture media. It has been shown that BY-2 cell treatment with 200 nM of melatonin improved viability of sugar-starved cells. It was correlated with higher starch content and phosphoenolpyruvate carboxykinase (PEPCK) activity. The obtained results revealed that exogenous melatonin under specific conditions (stress) can play regulatory role in sugar metabolism, and it may modulate carbohydrate concentration in etiolated BY-2 cells. Moreover, our results confirmed the hypothesis that if the starch is synthesised even in sugar-starved cells, it is highly probable that melatonin shifts the BY-2 cell metabolism on gluconeogenesis pathway and allows for synthesis of carbohydrates from nonsugar precursors, that is amino acids. These points to another defence strategy that was induced by exogenous melatonin applied in plants to overcome adverse environmental conditions. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Effect of Temperature on Precipitation Rate of Calcium Carbonate Produced through Microbial Metabolic Process of Bio Materials

    Prima Yane Putri

    2016-09-01

    Full Text Available Concrete is the most widely used construction material in civil engineering. But plain concrete is a brittle material and has little resistance to cracking. The cracking in concrete promotes deterioration such as the corrosion of reinforcing rebar, therefore, repair in filling the crack is often carried out. Recently, repair methods using bio-based materials associated with microbial metabolic processes leading to precipitation of calcium carbonate have been intensively studied. In this study, influencing factors on the precipitation rate depending on the constituents of bio-based material comprising yeast, glucose and calcium acetate mixed in tris buffer solution was examined for improving the rate of initial reactions. In addition, effect of temperature change on the amount of calcium carbonate precipitation was also investigated. The precipitates were identified by X-ray diffraction. It was shown that the increase of temperature lead to a change on calcium carbonate precipitation and caused the pH decrease under 7.0.

  7. The Oxidative Metabolism of Fossil Hydrocarbons and Sulfide Minerals by the Lithobiontic Microbial Community Inhabiting Deep Subterrestrial Kupferschiefer Black Shale

    Agnieszka Włodarczyk

    2018-05-01

    Full Text Available Black shales are one of the largest reservoirs of fossil organic carbon and inorganic reduced sulfur on Earth. It is assumed that microorganisms play an important role in the transformations of these sedimentary rocks and contribute to the return of organic carbon and inorganic sulfur to the global geochemical cycles. An outcrop of deep subterrestrial ~256-million-year-old Kupferschiefer black shale was studied to define the metabolic processes of the deep biosphere important in transformations of organic carbon and inorganic reduced sulfur compounds. This outcrop was created during mining activity 12 years ago and since then it has been exposed to the activity of oxygen and microorganisms. The microbial processes were described based on metagenome and metaproteome studies as well as on the geochemistry of the rock. The microorganisms inhabiting the subterrestrial black shale were dominated by bacterial genera such as Pseudomonas, Limnobacter, Yonghaparkia, Thiobacillus, Bradyrhizobium, and Sulfuricaulis. This study on black shale was the first to detect archaea and fungi, represented by Nitrososphaera and Aspergillus genera, respectively. The enzymatic oxidation of fossil aliphatic and aromatic hydrocarbons was mediated mostly by chemoorganotrophic bacteria, but also by archaea and fungi. The dissimilative enzymatic oxidation of primary reduced sulfur compounds was performed by chemolithotrophic bacteria. The geochemical consequences of microbial activity were the oxidation and dehydrogenation of kerogen, as well as oxidation of sulfide minerals.

  8. Metabolic and phylogenetic analysis of microbial communities during phytoremediation of soil contaminated with weathered hydrocarbons and heavy metals.

    Palmroth, Marja R T; Koskinen, Perttu E P; Kaksonen, Anna H; Münster, Uwe; Pichtel, John; Puhakka, Jaakko A

    2007-12-01

    In the current study, the microbial ecology of weathered hydrocarbon and heavy metal contaminated soil undergoing phytoremediation was studied. The relationship of functional diversity, measured as carbon source utilisation in Biolog plates and extracellular enzymatic activities, and genetic diversity of bacteria was evaluated. Denaturing gradient gel electrophoresis was used for community analyses at the species level. Bulk soil and rhizosphere soil from pine and poplar plantations were analysed separately to determine if the plant rhizosphere impacted hydrocarbon degradation. Prevailing microbial communities in the field site were both genetically and metabolically diverse. Furthermore, both tree rhizosphere and fertilisation affected the compositions of these communities and increased activities of extracellular aminopeptidases. In addition, the abundance of alkane hydroxylase and naphthalene dioxygenase genes in the communities was low, but the prevalence of these genes was increased by the addition of bioavailable hydrocarbons. Tree rhizosphere communities had greater hydrocarbon degradation potential than those of bulk soil. Hydrocarbon utilising communities were dominated generally by the species Ralstonia eutropha and bacteria belonging to the genus Burkholderia. Despite the presence of viable hydrocarbon-degrading microbiota, decomposition of hydrocarbons from weathered hydrocarbon contaminated soil over four years, regardless of the presence of vegetation, was low in unfertilised soil. Compost addition enhanced the removal of hydrocarbons.

  9. Methane-metabolizing microbial communities in sediments of the Haima cold seep area, northwest slope of the South China Sea.

    Niu, Mingyang; Fan, Xibei; Zhuang, Guangchao; Liang, Qianyong; Wang, Fengping

    2017-09-01

    Cold seeps are widespread chemosynthetic ecosystems in the deep-sea environment, and cold seep microbial communities of the South China Sea are poorly constrained. Here we report on the archaeal communities, particularly those involved in methane metabolization, in sediments of a newly discovered cold seep (named 'Haima') on the northwest slope of the South China Sea. Archaeal diversity, abundance and distribution were investigated in two piston cores collected from a seep area (QDN-14B) and a non-seep control site (QDN-31B). Geochemical investigation of the QDN-14B core identified an estimated sulfate-methane transition zone (Estimated SMTZ) at 300-400 cm below sea floor (cmbsf), where a high abundance of anaerobic methane-oxidizing archaea (ANME) occurred, as revealed by analysis of the 16S rRNA gene and the gene (mcrA) encoding the α-subunit of the key enzyme methyl-coenzyme M reductase. ANME-2a/b was predominant in the upper and middle layers of the estimated SMTZ, whereas ANME-1b outcompeted ANME-2 in the sulfate-depleted bottom layers of the estimated SMTZ and the methanogenic zone. Fine-scale phylogenetic analysis further divided the ANME-1b group into three subgroups with different distribution patterns: ANME-1bI, ANME-1bII and ANME-1bIII. Multivariate analyses indicated that dissolved inorganic carbon and sulfate may be important factors controlling the composition of the methane-metabolizing community. Our study on ANME niche separation and interactions with other archaeal groups improves our understanding of the metabolic diversity and flexibility of ANME, and the findings further suggest that ANME subgroups may have evolved diversified/specified metabolic capabilities other than syntrophic anaerobic oxidation of methane coupled with sulfate reduction in marine sediments. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Molecular Imaging Of Metabolic Reprogramming In Mutant IDH Cells

    Pavithra eViswanath

    2016-03-01

    Full Text Available Mutations in the metabolic enzyme isocitrate dehydrogenase (IDH have recently been identified as drivers in the development of several tumor types. Most notably, cytosolic IDH1 is mutated in 70-90% of low-grade gliomas and upgraded glioblastomas, and mitochondrial IDH2 is mutated in ~20% of acute myeloid leukemia cases. Wild-type IDH catalyzes the interconversion of isocitrate to α-ketoglutarate (α-KG. Mutations in the enzyme lead to loss of wild-type enzymatic activity and a neomorphic activity that converts α-KG to 2-hydroxyglutarate (2-HG. In turn, 2-HG, which has been termed an oncometabolite, inhibits key α-KG- dependent enzymes, resulting in alterations of the cellular epigenetic profile and, subsequently, inhibition of differentiation and initiation of tumorigenesis. In addition, it is now clear that the IDH mutation also induces a broad metabolic reprogramming that extends beyond 2-HG production, and this reprogramming often differs from what has been previously reported in other cancer types. In this review we will discuss in detail what is known to date about the metabolic reprogramming of mutant IDH cells and how this reprogramming has been investigated using molecular metabolic imaging. We will describe how metabolic imaging has helped shed light on the basic biology of mutant IDH cells and how this information can be leveraged to identify new therapeutic targets and to develop new clinically translatable imaging methods to detect and monitor mutant IDH tumors in vivo.

  11. Recent Updates on Treatment of Ocular Microbial Infections by Stem Cell Therapy: A Review

    Seoh Wei Teh

    2018-02-01

    Full Text Available Ocular microbial infection has emerged as a major public health crisis during the past two decades. A variety of causative agents can cause ocular microbial infections; which are characterized by persistent and destructive inflammation of the ocular tissue; progressive visual disturbance; and may result in loss of visual function in patients if early and effective treatments are not received. The conventional therapeutic approaches to treat vision impairment and blindness resulting from microbial infections involve antimicrobial therapy to eliminate the offending pathogens or in severe cases; by surgical methods and retinal prosthesis replacing of the infected area. In cases where there is concurrent inflammation, once infection is controlled, anti-inflammatory agents are indicated to reduce ocular damage from inflammation which ensues. Despite advances in medical research; progress in the control of ocular microbial infections remains slow. The varying level of ocular tissue recovery in individuals and the incomplete visual functional restoration indicate the chief limitations of current strategies. The development of a more extensive therapy is needed to help in healing to regain vision in patients. Stem cells are multipotent stromal cells that can give rise to a vast variety of cell types following proper differentiation protocol. Stem cell therapy shows promise in reducing inflammation and repairing tissue damage on the eye caused by microbial infections by its ability to modulate immune response and promote tissue regeneration. This article reviews a selected list of common infectious agents affecting the eye; which include fungi; viruses; parasites and bacteria with the aim of discussing the current antimicrobial treatments and the associated therapeutic challenges. We also provide recent updates of the advances in stem cells studies on sepsis therapy as a suggestion of optimum treatment regime for ocular microbial infections.

  12. Recent Updates on Treatment of Ocular Microbial Infections by Stem Cell Therapy: A Review.

    Teh, Seoh Wei; Mok, Pooi Ling; Abd Rashid, Munirah; Bastion, Mae-Lynn Catherine; Ibrahim, Normala; Higuchi, Akon; Murugan, Kadarkarai; Mariappan, Rajan; Subbiah, Suresh Kumar

    2018-02-13

    Ocular microbial infection has emerged as a major public health crisis during the past two decades. A variety of causative agents can cause ocular microbial infections; which are characterized by persistent and destructive inflammation of the ocular tissue; progressive visual disturbance; and may result in loss of visual function in patients if early and effective treatments are not received. The conventional therapeutic approaches to treat vision impairment and blindness resulting from microbial infections involve antimicrobial therapy to eliminate the offending pathogens or in severe cases; by surgical methods and retinal prosthesis replacing of the infected area. In cases where there is concurrent inflammation, once infection is controlled, anti-inflammatory agents are indicated to reduce ocular damage from inflammation which ensues. Despite advances in medical research; progress in the control of ocular microbial infections remains slow. The varying level of ocular tissue recovery in individuals and the incomplete visual functional restoration indicate the chief limitations of current strategies. The development of a more extensive therapy is needed to help in healing to regain vision in patients. Stem cells are multipotent stromal cells that can give rise to a vast variety of cell types following proper differentiation protocol. Stem cell therapy shows promise in reducing inflammation and repairing tissue damage on the eye caused by microbial infections by its ability to modulate immune response and promote tissue regeneration. This article reviews a selected list of common infectious agents affecting the eye; which include fungi; viruses; parasites and bacteria with the aim of discussing the current antimicrobial treatments and the associated therapeutic challenges. We also provide recent updates of the advances in stem cells studies on sepsis therapy as a suggestion of optimum treatment regime for ocular microbial infections.

  13. Influence of diet and microbial activity in the digestive tract on digestibility, and nitrogen and energy metabolism in rats and pigs

    Eggum, B O; Thorbek, G; Beames, R M

    1982-01-01

    -55 kg. Measurements were made on the influence of microbial activity in the digestive tract on digestibility and nitrogen and energy metabolism. Dietary inclusion of the antibiotic Nebacitin was the method used to reduce the microbial population. 2. The microbial activity in the hind-gut (mumol ATP....../g air-dry contents) of antibiotic-treated rats was reduced to approximately one-tenth of that of untreated rats. 3. Live-weight gain was not significantly affected in either species by a reduction in the microbial activity, in spite of a reduction in dry matter digestibility in animals with reduced...... microflora. 4. For rats on low-crude-fibre diets, a reduction in microflora reduced digestibility of all nutrients and energy and metabolizability of digestible energy by approximately 5.4%. All differences were highly significant. On high-crude-fibre diets the decrease was approximately 5.9%. In pigs...

  14. Oral Gingival Cell Cigarette Smoke Exposure Induces Muscle Cell Metabolic Disruption

    Andrea C. Baeder

    2016-01-01

    Full Text Available Cigarette smoke exposure compromises health through damaging multiple physiological systems, including disrupting metabolic function. The purpose of this study was to determine the role of oral gingiva in mediating the deleterious metabolic effects of cigarette smoke exposure on skeletal muscle metabolic function. Using an in vitro conditioned medium cell model, skeletal muscle cells were incubated with medium from gingival cells treated with normal medium or medium containing suspended cigarette smoke extract (CSE. Following incubation of muscle cells with gingival cell conditioned medium, muscle cell mitochondrial respiration and insulin signaling and action were determined as an indication of overall muscle metabolic health. Skeletal muscle cells incubated with conditioned medium of CSE-treated gingival cells had a profound reduction in mitochondrial respiration and respiratory control. Furthermore, skeletal muscle cells had a greatly reduced response in insulin-stimulated Akt phosphorylation and glycogen synthesis. Altogether, these results provide a novel perspective on the mechanism whereby cigarette smoke affects systemic metabolic function. In conclusion, we found that oral gingival cells treated with CSE create an altered milieu that is sufficient to both disrupted skeletal muscle cell mitochondrial function and insulin sensitivity.

  15. Metabolism and the Control of Cell Fate Decisions and Stem Cell Renewal

    Ito, Kyoko; Ito, Keisuke

    2016-01-01

    Although the stem cells of various tissues remain in the quiescent state to maintain their undifferentiated state, they also undergo cell divisions as required, and if necessary, even a single stem cell is able to provide for lifelong tissue homeostasis. Stem cell populations are precisely controlled by the balance between their symmetric and asymmetric divisions, with their division patterns determined by whether the daughter cells involved retain their self-renewal capacities. Recent studies have reported that metabolic pathways and the distribution of mitochondria are regulators of the division balance of stem cells and that metabolic defects can shift division balance toward symmetric commitment, which leads to stem cell exhaustion. It has also been observed that in asymmetric division, old mitochondria, which are central metabolic organelles, are segregated to the daughter cell fated to cell differentiation, whereas in symmetric division, young and old mitochondria are equally distributed between both daughter cells. Thus, metabolism and mitochondrial biology play important roles in stem cell fate decisions. As these decisions directly affect tissue homeostasis, understanding their regulatory mechanisms in the context of cellular metabolism is critical. PMID:27482603

  16. Electricity generation and microbial community in response to short-term changes in stack connection of self-stacked submersible microbial fuel cell powered by glycerol

    Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

    2017-01-01

    community. In this study, a self-stacked submersible microbial fuel cell (SSMFC) powered by glycerol was tested to elucidate this important issue. In series connection, the maximum voltage output reached to 1.15 V, while maximum current density was 5.73 mA in parallel. In both connections, the maximum power......Stack connection (i.e., in series or parallel) of microbial fuel cell (MFC) is an efficient way to boost the power output for practical application. However, there is little information available on short-term changes in stack connection and its effect on the electricity generation and microbial...... density increased with the initial glycerol concentration. However, the glycerol degradation was even faster in parallel connection. When the SSMFC was shifted from series to parallel connection, the reactor reached to a stable power output without any lag phase. Meanwhile, the anodic microbial community...

  17. Submersible microbial fuel cell sensor for monitoring microbial activity and BOD in groundwater: Focusing on impact of anodic biofilm on sensor applicability

    Zhang, Yifeng; Angelidaki, Irini

    2011-01-01

    was required for application of the sensor for microbial activity measurement, while biofilm‐colonized anode was needed for utilizing the sensor for BOD content measurement. The current density of SUMFC sensor equipped with a biofilm‐colonized anode showed linear relationship with BOD content, to up to 250 mg......A sensor, based on a submersible microbial fuel cell (SUMFC), was developed for in situ monitoring of microbial activity and biochemical oxygen demand (BOD) in groundwater. Presence or absence of a biofilm on the anode was a decisive factor for the applicability of the sensor. Fresh anode...

  18. Role of innate lymphoid cells in obesity and metabolic disease

    Saetang, Jirakrit; Sangkhathat, Surasak

    2018-01-01

    The immune system has previously been demonstrated to be associated with the pathophysiological development of metabolic abnormalities. However, the mechanisms linking immunity to metabolic disease remain to be fully elucidated. It has previously been suggested that innate lymphoid cells (ILCs) may be involved in the progression of numerous types of metabolic diseases as these cells act as suppressors and promoters for obesity and associated conditions, and are particularly involved in adipose tissue inflammation, which is a major feature of metabolic imbalance. Group 2 ILCs (ILC2s) have been revealed as anti-obese immune regulators by secreting anti-inflammatory cytokines and promoting the polarization of M2 macrophages, whereas group 1 ILCs (ILC1s), including natural killer cells, may promote adipose tissue inflammation via production of interferon-γ, which in turn polarizes macrophages toward the M1 type. The majority of studies to date have demonstrated the pathological association between ILCs and obesity in the context of adipose tissue inflammation, whereas the roles of ILCs in other organs which participate in obesity development have not been fully characterized. Therefore, identifying the roles of all types of ILCs as central components mediating obesity-associated inflammation, is of primary concern, and may lead to the discovery of novel preventative and therapeutic interventions. PMID:29138853

  19. Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation.

    Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

    2017-12-20

    Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food fermentation processes. Saccharomyces cerevisiae was dominant in gene transcription for urea biosynthesis and degradation. Lysinibacillus sphaericus was dominant for urea degradation. S. cerevisiae degraded 18% and L. sphaericus degraded 13% of urea in their corresponding single cultures, whereas they degraded 56% of urea in coculture after 12 h. Compared to single cultures, transcription of CAR1, DAL2, and argA, which are related to urea biosynthesis, decreased by 51, 36, and 69% in coculture, respectively. Transcription of DUR1 and ureA, which are related to urea degradation, increased by 227 and 70%, respectively. Thus, coexistence of the two strains promoted degradation of urea via transcriptional regulation of genes related to urea metabolism.

  20. Tumor microenvironment derived exosomes pleiotropically modulate cancer cell metabolism.

    Zhao, Hongyun; Yang, Lifeng; Baddour, Joelle; Achreja, Abhinav; Bernard, Vincent; Moss, Tyler; Marini, Juan C; Tudawe, Thavisha; Seviour, Elena G; San Lucas, F Anthony; Alvarez, Hector; Gupta, Sonal; Maiti, Sourindra N; Cooper, Laurence; Peehl, Donna; Ram, Prahlad T; Maitra, Anirban; Nagrath, Deepak

    2016-02-27

    Cancer-associated fibroblasts (CAFs) are a major cellular component of tumor microenvironment in most solid cancers. Altered cellular metabolism is a hallmark of cancer, and much of the published literature has focused on neoplastic cell-autonomous processes for these adaptations. We demonstrate that exosomes secreted by patient-derived CAFs can strikingly reprogram the metabolic machinery following their uptake by cancer cells. We find that CAF-derived exosomes (CDEs) inhibit mitochondrial oxidative phosphorylation, thereby increasing glycolysis and glutamine-dependent reductive carboxylation in cancer cells. Through 13C-labeled isotope labeling experiments we elucidate that exosomes supply amino acids to nutrient-deprived cancer cells in a mechanism similar to macropinocytosis, albeit without the previously described dependence on oncogenic-Kras signaling. Using intra-exosomal metabolomics, we provide compelling evidence that CDEs contain intact metabolites, including amino acids, lipids, and TCA-cycle intermediates that are avidly utilized by cancer cells for central carbon metabolism and promoting tumor growth under nutrient deprivation or nutrient stressed conditions.

  1. Tumor microenvironment derived exosomes pleiotropically modulate cancer cell metabolism

    Zhao, Hongyun; Yang, Lifeng; Baddour, Joelle; Achreja, Abhinav; Bernard, Vincent; Moss, Tyler; Marini, Juan C; Tudawe, Thavisha; Seviour, Elena G; San Lucas, F Anthony; Alvarez, Hector; Gupta, Sonal; Maiti, Sourindra N; Cooper, Laurence; Peehl, Donna; Ram, Prahlad T; Maitra, Anirban; Nagrath, Deepak

    2016-01-01

    Cancer-associated fibroblasts (CAFs) are a major cellular component of tumor microenvironment in most solid cancers. Altered cellular metabolism is a hallmark of cancer, and much of the published literature has focused on neoplastic cell-autonomous processes for these adaptations. We demonstrate that exosomes secreted by patient-derived CAFs can strikingly reprogram the metabolic machinery following their uptake by cancer cells. We find that CAF-derived exosomes (CDEs) inhibit mitochondrial oxidative phosphorylation, thereby increasing glycolysis and glutamine-dependent reductive carboxylation in cancer cells. Through 13C-labeled isotope labeling experiments we elucidate that exosomes supply amino acids to nutrient-deprived cancer cells in a mechanism similar to macropinocytosis, albeit without the previously described dependence on oncogenic-Kras signaling. Using intra-exosomal metabolomics, we provide compelling evidence that CDEs contain intact metabolites, including amino acids, lipids, and TCA-cycle intermediates that are avidly utilized by cancer cells for central carbon metabolism and promoting tumor growth under nutrient deprivation or nutrient stressed conditions. DOI: http://dx.doi.org/10.7554/eLife.10250.001 PMID:26920219

  2. Metformin Decouples Phospholipid Metabolism in Breast Cancer Cells.

    Tim A D Smith

    Full Text Available The antidiabetic drug metformin, currently undergoing trials for cancer treatment, modulates lipid and glucose metabolism both crucial in phospholipid synthesis. Here the effect of treatment of breast tumour cells with metformin on phosphatidylcholine (PtdCho metabolism which plays a key role in membrane synthesis and intracellular signalling has been examined.MDA-MB-468, BT474 and SKBr3 breast cancer cell lines were treated with metformin and [3H-methyl]choline and [14C(U]glucose incorporation and lipid accumulation determined in the presence and absence of lipase inhibitors. Activities of choline kinase (CK, CTP:phosphocholine cytidylyl transferase (CCT and PtdCho-phospholipase C (PLC were also measured. [3H] Radiolabelled metabolites were determined using thin layer chromatography.Metformin-treated cells exhibited decreased formation of [3H]phosphocholine but increased accumulation of [3H]choline by PtdCho. CK and PLC activities were decreased and CCT activity increased by metformin-treatment. [14C] incorporation into fatty acids was decreased and into glycerol was increased in breast cancer cells treated with metformin incubated with [14C(U]glucose.This is the first study to show that treatment of breast cancer cells with metformin induces profound changes in phospholipid metabolism.

  3. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    Logan, Bruce E.

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment. © 2008 American Chemical Society.

  4. Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light

    Xing, Defeng

    2009-09-01

    Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8-10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  5. Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light

    Xing, Defeng; Cheng, Shaoan; Regan, John M.; Logan, Bruce E.

    2009-01-01

    Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8-10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  6. Polymer Separators for High-Power, High-Efficiency Microbial Fuel Cells

    Chen, Guang

    2012-12-26

    Microbial fuel cells (MFCs) with hydrophilic poly(vinyl alcohol) (PVA) separators showed higher Coulombic efficiencies (94%) and power densities (1220 mW m-2) than cells with porous glass fiber separators or reactors without a separator after 32 days of operation. These remarkable increases in both the coublomic efficiency and the power production of the microbial fuel cells were made possible by the separator\\'s unique characteristics of fouling mitigation of the air cathode without a large increase in ionic resistance in the cell. This new type of polymer gel-like separator design will be useful for improving MFC reactor performance by enabling compact cell designs. © 2012 American Chemical Society.

  7. Laminar shear stress inhibits endothelial cell metabolism via KLF2-mediated repression of PFKFB3

    Doddaballapur, Anuradha; Michalik, Katharina M.; Manavski, Yosif; Lucas, Tina; Houtkooper, Riekelt H.; You, Xintian; Chen, Wei; Zeiher, Andreas M.; Potente, Michael; Dimmeler, Stefanie; Boon, Reinier A.

    2015-01-01

    Cellular metabolism was recently shown to regulate endothelial cell phenotype profoundly. Whether the atheroprotective biomechanical stimulus elicited by laminar shear stress modulates endothelial cell metabolism is not known. Here, we show that laminar flow exposure reduced glucose uptake and

  8. Probiotic modulation of symbiotic gut microbial-host metabolic interactions in a humanized microbiome mouse model

    Martin, F.P.J.; Wang, Y.; Sprenger, N.; Yap, K.S.; Rezzi, S.; Ramadan, Z.; Peré-Trepat, E.; Rochat, F.; Cherbut, C.; Bladeren, van P.J.; Fay, L.B.; Kochhar, S.; LindOn, J.C.; Holmes, E.; Nicholson, J.K.

    2008-01-01

    The transgenomic metabolic effects of exposure to either Lactobacillus paracasei or Lactobacillus rhamnosus probiotics have been measured and mapped in humanized extended genome mice (germ-free mice colonized with human baby flora). Statistical analysis of the compartmental fluctuations in diverse

  9. ReacKnock: identifying reaction deletion strategies for microbial strain optimization based on genome-scale metabolic network.

    Zixiang Xu

    Full Text Available Gene knockout has been used as a common strategy to improve microbial strains for producing chemicals. Several algorithms are available to predict the target reactions to be deleted. Most of them apply mixed integer bi-level linear programming (MIBLP based on metabolic networks, and use duality theory to transform bi-level optimization problem of large-scale MIBLP to single-level programming. However, the validity of the transformation was not proved. Solution of MIBLP depends on the structure of inner problem. If the inner problem is continuous, Karush-Kuhn-Tucker (KKT method can be used to reformulate the MIBLP to a single-level one. We adopt KKT technique in our algorithm ReacKnock to attack the intractable problem of the solution of MIBLP, demonstrated with the genome-scale metabolic network model of E. coli for producing various chemicals such as succinate, ethanol, threonine and etc. Compared to the previous methods, our algorithm is fast, stable and reliable to find the optimal solutions for all the chemical products tested, and able to provide all the alternative deletion strategies which lead to the same industrial objective.

  10. Type II NKT Cells in Inflammation, Autoimmunity, Microbial Immunity, and Cancer.

    Marrero, Idania; Ware, Randle; Kumar, Vipin

    2015-01-01

    Natural killer T cells (NKT) recognize self and microbial lipid antigens presented by non-polymorphic CD1d molecules. Two major NKT cell subsets, type I and II, express different types of antigen receptors (TCR) with distinct mode of CD1d/lipid recognition. Though type II NKT cells are less frequent in mice and difficult to study, they are predominant in human. One of the major subsets of type II NKT cells reactive to the self-glycolipid sulfatide is the best characterized and has been shown to induce a dominant immune regulatory mechanism that controls inflammation in autoimmunity and in anti-cancer immunity. Recently, type II NKT cells reactive to other self-glycolipids and phospholipids have been identified suggesting both promiscuous and specific TCR recognition in microbial immunity as well. Since the CD1d pathway is highly conserved, a detailed understanding of the biology and function of type II NKT cells as well as their interplay with type I NKT cells or other innate and adaptive T cells will have major implications for potential novel interventions in inflammatory and autoimmune diseases, microbial immunity, and cancer.

  11. Metabolic shift in lung alveolar cell mitochondria following acrolein exposure.

    Agarwal, Amit R; Yin, Fei; Cadenas, Enrique

    2013-11-15

    Acrolein, an α,β unsaturated electrophile, is an environmental pollutant released in ambient air from diesel exhausts and cooking oils. This study examines the role of acrolein in altering mitochondrial function and metabolism in lung-specific cells. RLE-6TN, H441, and primary alveolar type II (pAT2) cells were exposed to acrolein for 4 h, and its effect on mitochondrial oxygen consumption rates was studied by XF Extracellular Flux analysis. Low-dose acrolein exposure decreased mitochondrial respiration in a dose-dependent manner because of alteration in the metabolism of glucose in all the three cell types. Acrolein inhibited glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, leading to decreased substrate availability for mitochondrial respiration in RLE-6TN, H441, and pAT2 cells; the reduced GAPDH activity was compensated in pAT2 cells by an increase in the activity of glucose-6-phosphate dehydrogenase, the regulatory control of the pentose phosphate pathway. The decrease in pyruvate from glucose metabolism resulted in utilization of alternative sources to support mitochondrial energy production: palmitate-BSA complex increased mitochondrial respiration in RLE-6TN and pAT2 cells. The presence of palmitate in alveolar cells for surfactant biosynthesis may prove to be the alternative fuel source for mitochondrial respiration. Accordingly, a decrease in phosphatidylcholine levels and an increase in phospholipase A2 activity were found in the alveolar cells after acrolein exposure. These findings have implications for understanding the decrease in surfactant levels frequently observed in pathophysiological situations with altered lung function following exposure to environmental toxicants.

  12. Exploiting immune cell metabolic machinery for functional HIV cure and the prevention of inflammaging

    Palmer, Clovis S.; Palchaudhuri, Riya; Albargy, Hassan; Abdel-Mohsen, Mohamed; Crowe, Suzanne M.

    2018-01-01

    An emerging paradigm in immunology suggests that metabolic reprogramming and immune cell activation and functions are intricately linked. Viral infections, such as HIV infection, as well as cancer force immune cells to undergo major metabolic challenges. Cells must divert energy resources in order to mount an effective immune response. However, the fact that immune cells adopt specific metabolic programs to provide host defense against intracellular pathogens and how this metabolic shift impa...

  13. Long-term cathode performance and the microbial communities that develop in microbial fuel cells fed different fermentation endproducts

    Kiely, Patrick D.

    2011-01-01

    To better understand how cathode performance and substrates affected communities that evolved in these reactors over long periods of time, microbial fuel cells were operated for more than 1year with individual endproducts of lignocellulose fermentation (acetic acid, formic acid, lactic acid, succinic acid, or ethanol). Large variations in reactor performance were primarily due to the specific substrates, with power densities ranging from 835±21 to 62±1mW/m3. Cathodes performance degraded over time, as shown by an increase in power of up to 26% when the cathode biofilm was removed, and 118% using new cathodes. Communities that developed on the anodes included exoelectrogenic families, such as Rhodobacteraceae, Geobacteraceae, and Peptococcaceae, with the Deltaproteobacteria dominating most reactors. Pelobacter propionicus was the predominant member in reactors fed acetic acid, and it was abundant in several other MFCs. These results provide valuable insights into the effects of long-term MFC operation on reactor performance. © 2010 Elsevier Ltd.

  14. Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

    Yang, Fei; Ren, Lijiao; Pu, Yuepu; Logan, Bruce E.

    2013-01-01

    Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5

  15. Syntrophic interactions drive the hydrogen production from glucose at low temperature in microbial electrolysis cells

    Lu, Lu; Xing, Defeng; Ren, Nanqi; Logan, Bruce E.

    2012-01-01

    H2 can be obtained from glucose by fermentation at mesophilic temperatures, but here we demonstrate that hydrogen can also be obtained from glucose at low temperatures using microbial electrolysis cells (MECs). H2 was produced from glucose at 4°C

  16. High hydrogen production from glycerol or glucose by electrohydrogenesis using microbial electrolysis cells

    Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

    2009-01-01

    The use of glycerol for hydrogen gas production was examined via electrohydrogenesis using microbial electrolysis cells (MECs). A hydrogen yield of 3.9 mol-H2/mol was obtained using glycerol, which is higher than that possible by fermentation

  17. Improving the cathode of a microbial fuel cell for efficient electricity production

    Heijne, ter A.

    2010-01-01

    The worldwide demand for energy is increasing. At the same time, energy rich wastewaters are currently purified by oxygen supply, which costs a lot of energy. The Microbial Fuel Cell is a new technology that offers advantages in both directions: it produces electricity while purifying wastewaters.

  18. Renewable sustainable biocatalyzed electricity production in a photosynthetic algal microbial fuel cell (PAMFC)

    Strik, D.P.B.T.B.; Terlouw, H.; Hamelers, H.V.M.; Buisman, C.J.N.

    2008-01-01

    Electricity production via solar energy capturing by living higher plants and microalgae in combination with microbial fuel cells are attractive because these systems promise to generate useful energy in a renewable, sustainable, and efficient manner. This study describes the proof of principle of a

  19. The importance of OH − transport through anion exchange membrane in microbial electrolysis cells

    Ye, Yaoli; Logan, Bruce

    2018-01-01

    In two-chamber microbial electrolysis cells (MECs) with anion exchange membranes (AEMs), a phosphate buffer solution (PBS) is typically used to avoid increases in catholyte pH as Nernst equation calculations indicate that high pHs adversely impact

  20. Optimization of catholyte concentration and anolyte pHs in two chamber microbial electrolysis cells

    Nam, Joo-Youn; Logan, Bruce E.

    2012-01-01

    The hydrogen production rate in a microbial electrolysis cell (MEC) using a non-buffered saline catholyte (NaCl) can be optimized through proper control of the initial anolyte pH and catholyte NaCl concentration. The highest hydrogen yield of 3

  1. Microbial Electrodialysis Cell for Simultaneous Water Desalination and Hydrogen Gas Production

    Mehanna, Maha; Kiely, Patrick D.; Call, Douglas F.; Logan, Bruce. E.

    2010-01-01

    A new approach to water desalination is to use exoelectrogenic bacteria to generate electrical power from the biodegradation of organic matter, moving charged ions from a middle chamber between two membranes in a type of microbial fuel cell called a microbial desalination cell. Desalination efficiency using this approach is limited by the voltage produced by the bacteria. Here we examine an alternative strategy based on boosting the voltage produced by the bacteria to achieve hydrogen gas evolution from the cathode using a three-chambered system we refer to as a microbial electrodialysis cell (MEDC). We examined the use of the MEDC process using two different initial NaCl concentrations of 5 g/L and 20 g/L. Conductivity in the desalination chamber was reduced by up to 68 ± 3% in a single fed-batch cycle, with electrical energy efficiencies reaching 231 ± 59%, and maximum hydrogen production rates of 0.16 ± 0.05 m3 H2/m3 d obtained at an applied voltage of 0.55 V. The advantage of this system compared to a microbial fuel cell approach is that the potentials between the electrodes can be better controlled, and the hydrogen gas that is produced can be used to recover energy to make the desalination process self-sustaining with respect to electrical power requirements. © 2010 American Chemical Society.

  2. The potential of whey in driving microbial fuel cells: A dual prospect ...

    Renewable and green energy resources are paramount to environmental sustainability. Microbial fuel cells (MFCs) are potential candidates for these alternatives but there is need to search for cheaper fuels to drive the MFCs for realistic large scale applications. A high strength effluent such as whey, which poses a serious ...

  3. Microbial Electrodialysis Cell for Simultaneous Water Desalination and Hydrogen Gas Production

    Mehanna, Maha

    2010-12-15

    A new approach to water desalination is to use exoelectrogenic bacteria to generate electrical power from the biodegradation of organic matter, moving charged ions from a middle chamber between two membranes in a type of microbial fuel cell called a microbial desalination cell. Desalination efficiency using this approach is limited by the voltage produced by the bacteria. Here we examine an alternative strategy based on boosting the voltage produced by the bacteria to achieve hydrogen gas evolution from the cathode using a three-chambered system we refer to as a microbial electrodialysis cell (MEDC). We examined the use of the MEDC process using two different initial NaCl concentrations of 5 g/L and 20 g/L. Conductivity in the desalination chamber was reduced by up to 68 ± 3% in a single fed-batch cycle, with electrical energy efficiencies reaching 231 ± 59%, and maximum hydrogen production rates of 0.16 ± 0.05 m3 H2/m3 d obtained at an applied voltage of 0.55 V. The advantage of this system compared to a microbial fuel cell approach is that the potentials between the electrodes can be better controlled, and the hydrogen gas that is produced can be used to recover energy to make the desalination process self-sustaining with respect to electrical power requirements. © 2010 American Chemical Society.

  4. Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell

    Deng, Qian; Li, Xinyang; Zuo, Jiane.; Ling, Alison; Logan, Bruce E.

    2010-01-01

    An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m-2, compared to lower values with cathodes made of plain carbon paper

  5. Resilience of roof-top Plant-Microbial Fuel Cells during Dutch winter

    Helder, M.; Strik, D.P.B.T.B.; Timmers, R.A.; Reas, S.M.T.; Hamelers, H.V.M.; Buisman, C.J.N.

    2013-01-01

    The Plant-Microbial Fuel Cell (P-MFC) is in theory a technology that could produce sustainable electricity continuously. We operated two designs of the P-MFC under natural roof-top conditions in the Netherlands for 221 days, including winter, to test its resilience. Current and power densities are

  6. Power output of microbial fuel cell emphasizing interaction of anodic binder with bacteria

    Li, Hongying; Liao, Bo; Xiong, Juan; Zhou, Xingwang; Zhi, Huozhen; Liu, Xiang; Li, Xiaoping; Li, Weishan

    2018-03-01

    Electrochemically active biofilm is necessary for the electron transfer between bacteria and anodic electrode in microbial fuel cells and selecting the type of anodic electrode material that favours formation of electrochemically active biofilm is crucial for the microbial fuel cell operation. We report a new finding that the interaction of anodic binder with bacteria plays more important role than its hydrophilicity for forming an electrochemically active biofilm, which is emphasized by applying poly(bisphenol A-co-epichorohydrin) as an anodic binder of the microbial fuel cell based on carbon nanotubes as anodic electrode and Escherichia coli as bacterium. The physical characterizations and electrochemical measurements demonstrate that poly(bisphenol A-co-epichorohydrin) exhibits a strong interaction with bacteria and thus provides the microbial fuel cell with excellent power density output. The MFC using poly(bisphenol A-co-epichorohydrin) reaches a maximum power density output of 3.8 W m-2. This value is larger than that of the MFCs using polytetrafluoroethylene that has poorer hydrophilicity, or polyvinyl alcohol that has better hydrophilicity but exhibits weaker interaction with bacteria than poly(bisphenol A-co-epichorohydrin).

  7. Use of a Burkholderia cenocepacia ABTS Oxidizer in a Microbial Fuel Cell

    Microbial fuel cells (MFCs) often use biological processes to generate electrons from organic material contained in the anode chamber and abiotic processes employing atmospheric oxygen as the oxidant in the cathode chamber. This study investigated the accumulation of an oxidant in bacterial cultures...

  8. DESHARKY: automatic design of metabolic pathways for optimal cell growth.

    Rodrigo, Guillermo; Carrera, Javier; Prather, Kristala Jones; Jaramillo, Alfonso

    2008-11-01

    The biological solution for synthesis or remediation of organic compounds using living organisms, particularly bacteria and yeast, has been promoted because of the cost reduction with respect to the non-living chemical approach. In that way, computational frameworks can profit from the previous knowledge stored in large databases of compounds, enzymes and reactions. In addition, the cell behavior can be studied by modeling the cellular context. We have implemented a Monte Carlo algorithm (DESHARKY) that finds a metabolic pathway from a target compound by exploring a database of enzymatic reactions. DESHARKY outputs a biochemical route to the host metabolism together with its impact in the cellular context by using mathematical models of the cell resources and metabolism. Furthermore, we provide the sequence of amino acids for the enzymes involved in the route closest phylogenetically to the considered organism. We provide examples of designed metabolic pathways with their genetic load characterizations. Here, we have used Escherichia coli as host organism. In addition, our bioinformatic tool can be applied for biodegradation or biosynthesis and its performance scales with the database size. Software, a tutorial and examples are freely available and open source at http://soft.synth-bio.org/desharky.html

  9. Effects of 3-styrylchromones on metabolic profiles and cell death in oral squamous cell carcinoma cells

    Hiroshi Sakagami

    2015-01-01

    Full Text Available 4H-1-benzopyran-4-ones (chromones are important naturally-distributing compounds. As compared with flavones, isoflavones and 2-styrylchromones, there are only few papers of 3-styrylchromones that have been published. We have previously reported that among fifteen 3-styrylchromone derivatives, three new synthetic compounds that have OCH3 group at the C-6 position of chromone ring, (E-3-(4-hydroxystyryl-6-methoxy-4H-chromen-4-one (compound 11, (E-6-methoxy-3-(4-methoxystyryl-4H-chromen-4-one (compound 4, (E-6-methoxy-3-(3,4,5-trimethoxystyryl-4H-chromen-4-one (compound 6 showed much higher cytotoxicities against four epithelial human oral squamous cell carcinoma (OSCC lines than human normal oral mesenchymal cells. In order to further confirm the tumor specificities of these compounds, we compared their cytotoxicities against both human epithelial malignant and non-malignant cells, and then investigated their effects on fine cell structures and metabolic profiles and cell death in human OSCC cell line HSC-2. Cytotoxicities of compounds 4, 6, 11 were assayed with MTT method. Fine cell structures were observed under transmission electron microscope. Cellular metabolites were extracted with methanol and subjected to CE-TOFMS analysis. Compounds 4, 6, 11 showed much weaker cytotoxicity against human oral keratinocyte and primary human gingival epithelial cells, as compared with HSC-2, confirming their tumor-specificity, whereas doxorubicin and 5-FU were highly cytotoxic to these normal epithelial cells, giving unexpectedly lower tumor-specificity. The most cytotoxic compound 11, induced the mitochondrial vacuolization, autophagy suppression followed by apoptosis induction, and changes in the metabolites involved in amino acid and glycerophospholipid metabolisms. Chemical modification of lead compound 11 may be a potential choice for designing new type of anticancer drugs.

  10. Transforming Lactococcus lactis into a microbial cell factory

    Petersen, Kia Vest

    the potential of Lactococcus lactis as a platform organism for production of biofuels and-chemicals with a focus on characterization and optimization of the xylose metabolism. The plant isolate L. lactis KF147 was selected as the potential platform organism due to its natural ability to utilize both the pentose....... To simplify further analysis arcA encoding the arginine deiminase was deleted, thus eliminating the arginine catabolism. We found that in L. lactis KF147 xylose is metabolized through two pathways namely the phosphoketolase pathway and the non-oxidative part of the pentose phosphate pathway. The only products......, and ethanol. Three adaptive mutations were identified in AD29. Two is by all accounts involved in regulatory mechanisms either to stress (yhfB) or more globally (ytgF), and the last facilitate improved uptake of xylose (ptnC). Based on the above findings we conclude that L. lactis KF147 possesses many...

  11. Cross-reactive microbial peptides can modulate HIV-specific CD8+ T cell responses.

    Christopher W Pohlmeyer

    Full Text Available Heterologous immunity is an important aspect of the adaptive immune response. We hypothesized that this process could modulate the HIV-1-specific CD8+ T cell response, which has been shown to play an important role in HIV-1 immunity and control. We found that stimulation of peripheral blood mononuclear cells (PBMCs from HIV-1-positive subjects with microbial peptides that were cross-reactive with immunodominant HIV-1 epitopes resulted in dramatic expansion of HIV-1-specific CD8+ T cells. Interestingly, the TCR repertoire of HIV-1-specific CD8+ T cells generated by ex vivo stimulation of PBMCs using HIV-1 peptide was different from that of cells stimulated with cross-reactive microbial peptides in some HIV-1-positive subjects. Despite these differences, CD8+ T cells stimulated with either HIV-1 or cross-reactive peptides effectively suppressed HIV-1 replication in autologous CD4+ T cells. These data suggest that exposure to cross-reactive microbial antigens can modulate HIV-1-specific immunity.

  12. A defined co-culture of Geobacter sulfurreducens and Escherichia coli in a membrane-less microbial fuel cell.

    Bourdakos, Nicholas; Marsili, Enrico; Mahadevan, Radhakrishnan

    2014-04-01

    Wastewater-fed microbial fuel cells (MFCs) are a promising technology to treat low-organic carbon wastewater and recover part of the chemical energy in wastewater as electrical power. However, the interactions between electrochemically active and fermentative microorganisms cannot be easily studied in wastewater-fed MFCs because of their complex microbial communities. Defined co-culture MFCs provide a detailed understanding of such interactions. In this study, we characterize the extracellular metabolites in laboratory-scale membrane-less MFCs inoculated with Geobacter sulfurreducens and Escherichia coli co-culture and compare them with pure culture MFCs. G. sulfurreducens MFCs are sparged to maintain anaerobic conditions, while co-culture MFCs rely on E. coli for oxygen removal. G. sulfurreducens MFCs have a power output of 128 mW m(-2) , compared to 63 mW m(-2) from the co-culture MFCs. Analysis of metabolites shows that succinate production in co-culture MFCs decreases current production by G. sulfurreducens and that the removal of succinate is responsible for the increased current density in the late co-culture MFCs. Interestingly, pH adjustment is not required for co-culture MFCs but a base addition is necessary for E. coli MFCs and cultures in vials. Our results show that defined co-culture MFCs provide clear insights into metabolic interactions among bacteria while maintaining a low operational complexity. © 2013 Wiley Periodicals, Inc.

  13. Unfolding Role of a Danger Molecule Adenosine Signaling in Modulation of Microbial Infection and Host Cell Response

    Jaden S. Lee

    2018-01-01

    Full Text Available Ectonucleotidases CD39 and CD73, specific nucleotide metabolizing enzymes located on the surface of the host, can convert a pro-inflammatory environment driven by a danger molecule extracellular-ATP to an adenosine-mediated anti-inflammatory milieu. Accordingly, CD39/CD73 signaling has been strongly implicated in modulating the intensity, duration, and composition of purinergic danger signals delivered to host. Recent studies have eluted potential roles for CD39 and CD73 in selective triggering of a variety of host immune cells and molecules in the presence of pathogenic microorganisms or microbial virulence molecules. Growing evidence also suggests that CD39 and CD73 present complimentary, but likely differential, actions against pathogens to shape the course and severity of microbial infection as well as the associated immune response. Similarly, adenosine receptors A2A and A2B have been proposed to be major immunomodulators of adenosine signaling during chronic inflammatory conditions induced by opportunistic pathogens, such as oral colonizer Porphyromonas gingivalis. Therefore, we here review the recent studies that demonstrate how complex network of molecules in the extracellular adenosine signaling machinery and their interactions can reshape immune responses and may also be targeted by opportunistic pathogens to establish successful colonization in human mucosal tissues and modulate the host immune response.

  14. Dynamics of Panax ginseng Rhizospheric Soil Microbial Community and Their Metabolic Function

    Yong Li

    2014-01-01

    Full Text Available The bacterial communities of 1- to 6-year ginseng rhizosphere soils were characterized by culture-independent approaches, random amplified polymorphic DNA (RAPD, and amplified ribosomal DNA restriction analysis (ARDRA. Culture-dependent method (Biolog was used to investigate the metabolic function variance of microbe living in rhizosphere soil. Results showed that significant genetic and metabolic function variance were detected among soils, and, with the increasing of cultivating years, genetic diversity of bacterial communities in ginseng rhizosphere soil tended to be decreased. Also we found that Verrucomicrobia, Acidobacteria, and Proteobacteria were the dominants in rhizosphere soils, but, with the increasing of cultivating years, plant disease prevention or plant growth promoting bacteria, such as Pseudomonas, Burkholderia, and Bacillus, tended to be rare.

  15. Effect of lineage-specific metabolic traits of Lactobacillus reuteri on sourdough microbial ecology.

    Lin, Xiaoxi B; Gänzle, Michael G

    2014-09-01

    This study determined the effects of specific metabolic traits of Lactobacillus reuteri on its competitiveness in sourdoughs. The competitiveness of lactobacilli in sourdough generally depends on their growth rate; acid resistance additionally contributes to competitiveness in sourdoughs with long fermentation times. Glycerol metabolism via glycerol dehydratase (gupCDE) accelerates growth by the regeneration of reduced cofactors; glutamate metabolism via glutamate decarboxylase (gadB) increases acid resistance by generating a proton motive force. Glycerol and glutamate metabolisms are lineage-specific traits in L. reuteri; therefore, this study employed glycerol dehydratase-positive sourdough isolates of human-adapted L. reuteri lineage I, glutamate decarboxylase-positive strains of rodent-adapted L. reuteri lineage II, as well as mutants with deletions in gadB or gupCDE. The competitivenesses of the strains were quantified by inoculation of wheat and sorghum sourdoughs with defined strains, followed by propagation of doughs with a 10% inoculum and 12-h or 72-h fermentation cycles. Lineage I L. reuteri strains dominated sourdoughs propagated with 12-h fermentation cycles; lineage II L. reuteri strains dominated sourdoughs propagated with 72-h fermentation cycles. L. reuteri 100-23ΔgadB was outcompeted by its wild-type strain in sourdoughs fermented with 72-h fermentation cycles; L. reuteri FUA3400ΔgupCDE was outcompeted by its wild-type strain in sourdoughs fermented with both 12-h and 72-h fermentation cycles. Competition experiments with isogenic pairs of strains resulted in a constant rate of strain displacement of the less competitive mutant strain. In conclusion, lineage-specific traits of L. reuteri determine the competitiveness of this species in sourdough fermentations. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  16. Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

    Qiannan Peng; Shuaiming Jiang; Jieling Chen; Chenchen Ma; Dongxue Huo; Yuyu Shao; Jiachao Zhang; Jiachao Zhang

    2018-01-01

    Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria we...

  17. Metabolic reprogramming in the tumour microenvironment: a hallmark shared by cancer cells and T lymphocytes.

    Allison, Katrina E; Coomber, Brenda L; Bridle, Byram W

    2017-10-01

    Altered metabolism is a hallmark of cancers, including shifting oxidative phosphorylation to glycolysis and up-regulating glutaminolysis to divert carbon sources into biosynthetic pathways that promote proliferation and survival. Therefore, metabolic inhibitors represent promising anti-cancer drugs. However, T cells must rapidly divide and survive in harsh microenvironments to mediate anti-cancer effects. Metabolic profiles of cancer cells and activated T lymphocytes are similar, raising the risk of metabolic inhibitors impairing the immune system. Immune checkpoint blockade provides an example of how metabolism can be differentially impacted to impair cancer cells but support T cells. Implications for research with metabolic inhibitors are discussed. © 2017 John Wiley & Sons Ltd.

  18. Inhibition of microbial metabolism in anaerobic lagoons by selected sulfonamides, tetracyclines, lincomycin, and tylosin tartrate

    Loftin, Keith A.; Henny, Cynthia; Adams, Craig D.; Surampali, Rao; Mormile, Melanie R.

    2005-01-01

    Antibiotics are used to maintain healthy livestock and to promote weight gain in concentrated animal feed operations. Antibiotics rarely are metabolized completely by livestock and, thus, are often present in livestock waste and in waste-treatment lagoons. The introduction of antibiotics into anaerobic lagoons commonly used for swine waste treatment has the potential for negative impacts on lagoon performance, which relies on a consortium of microbes ranging from fermentative microorganisms to methanogens. To address this concern, the effects of eight common veterinary antibiotics on anaerobic activity were studied. Anaerobic microcosms, prepared from freshly collected lagoon slurries, were amended with individual antibiotics at 10 mg/L for the initial screening study and at 1, 5, and 25 mg/L for the dose-response study. Monitored metabolic indicators included hydrogen, methane, and volatile fatty acid concentrations as well as chemical oxygen demand. The selected antibiotics significantly inhibited methane production relative to unamended controls, thus indicating that antibiotics at concentrations commonly found in swine lagoons can negatively impact anaerobic metabolism. Additionally, historical antibiotic usage seems to be a potential factor in affecting methane production. Specifically, less inhibition of methane production was noted in samples taken from the lagoon with a history of multiple-antibiotic use.

  19. Inhibition of microbial metabolism in anaerobic lagoons by selected sulfonamides, tetracyclines, lincomycin, and tylosin tartrate.

    Loftin, Keith A; Henny, Cynthia; Adams, Craig D; Surampali, Rao; Mormile, Melanie R

    2005-04-01

    Antibiotics are used to maintain healthy livestock and to promote weight gain in concentrated animal feed operations. Antibiotics rarely are metabolized completely by livestock and, thus, are often present in livestock waste and in waste-treatment lagoons. The introduction of antibiotics into anaerobic lagoons commonly used for swine waste treatment has the potential for negative impacts on lagoon performance, which relies on a consortium of microbes ranging from fermentative microorganisms to methanogens. To address this concern, the effects of eight common veterinary antibiotics on anaerobic activity were studied. Anaerobic microcosms, prepared from freshly collected lagoon slurries, were amended with individual antibiotics at 10 mg/L for the initial screening study and at 1, 5, and 25 mg/L for the dose-response study. Monitored metabolic indicators included hydrogen, methane, and volatile fatty acid concentrations as well as chemical oxygen demand. The selected antibiotics significantly inhibited methane production relative to unamended controls, thus indicating that antibiotics at concentrations commonly found in swine lagoons can negatively impact anaerobic metabolism. Additionally, historical antibiotic usage seems to be a potential factor in affecting methane production. Specifically, less inhibition of methane production was noted in samples taken from the lagoon with a history of multiple-antibiotic use.

  20. Rapid prototyping of microbial cell factories via genome-scale engineering.

    Si, Tong; Xiao, Han; Zhao, Huimin

    2015-11-15

    Advances in reading, writing and editing genetic materials have greatly expanded our ability to reprogram biological systems at the resolution of a single nucleotide and on the scale of a whole genome. Such capacity has greatly accelerated the cycles of design, build and test to engineer microbes for efficient synthesis of fuels, chemicals and drugs. In this review, we summarize the emerging technologies that have been applied, or are potentially useful for genome-scale engineering in microbial systems. We will focus on the development of high-throughput methodologies, which may accelerate the prototyping of microbial cell factories. Copyright © 2014 Elsevier Inc. All rights reserved.