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Sample records for 6-acre anaerobic cell

  1. Anaerobic

    MedlinePlus

    ... shock. Anaerobic is the opposite of aerobic . In exercise, our bodies need to perform both anaerobic and aerobic reactions ... during shorter, more intense activities like sprinting. Anaerobic ... removing the lactic acid by providing oxygen to their bodies.

  2. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    EPA Science Inventory

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  3. Proteome analysis of aerobically and anaerobically grown Saccharomyces cerevisiae cells.

    PubMed

    Bruckmann, Astrid; Hensbergen, Paul J; Balog, Crina I A; Deelder, André M; Brandt, Raymond; Snoek, I S Ishtar; Steensma, H Yde; van Heusden, G Paul H

    2009-01-30

    The yeast Saccharomyces cerevisiae is able to grow under aerobic as well as anaerobic conditions. We and others previously found that transcription levels of approximately 500 genes differed more than two-fold when cells from anaerobic and aerobic conditions were compared. Here, we addressed the effect of anaerobic growth at the post-transcriptional level by comparing the proteomes of cells isolated from steady-state glucose-limited anaerobic and aerobic cultures. Following two-dimensional gel electrophoresis and mass spectrometry we identified 110 protein spots, corresponding to 75 unique proteins, of which the levels differed more than two-fold between aerobically and anaerobically-grown cells. For 21 of the 110 spots, the intensities decreased more than two-fold whereas the corresponding mRNA levels increased or did not change significantly under anaerobic conditions. The intensities of the other 89 spots changed in the same direction as the mRNA levels of the corresponding genes, although to different extents. For some genes of glycolysis a small increase in mRNA levels, 1.5-2 fold, corresponded to a 5-10 fold increase in protein levels. Extrapolation of our results suggests that transcriptional regulation is the major but not exclusive mechanism for adaptation of S. cerevisiae to anaerobic growth conditions.

  4. Single-Cell Analysis of Growth and Cell Division of the Anaerobe Desulfovibrio vulgaris Hildenborough.

    PubMed

    Fievet, Anouchka; Ducret, Adrien; Mignot, Tâm; Valette, Odile; Robert, Lydia; Pardoux, Romain; Dolla, Alain R; Aubert, Corinne

    2015-01-01

    Recent years have seen significant progress in understanding basic bacterial cell cycle properties such as cell growth and cell division. While characterization and regulation of bacterial cell cycle is quite well-documented in the case of fast growing aerobic model organisms, no data has been so far reported for anaerobic bacteria. This lack of information in anaerobic microorganisms can mainly be explained by the absence of molecular and cellular tools such as single cell microscopy and fluorescent probes usable for anaerobes and essential to study cellular events and/or subcellular localization of the actors involved in cell cycle. In this study, single-cell microscopy has been adapted to study for the first time, in real time, the cell cycle of a bacterial anaerobe, Desulfovibrio vulgaris Hildenborough (DvH). This single-cell analysis provides mechanistic insights into the cell division cycle of DvH, which seems to be governed by the recently discussed so-called incremental model that generates remarkably homogeneous cell sizes. Furthermore, cell division was reversibly blocked during oxygen exposure. This may constitute a strategy for anaerobic cells to cope with transient exposure to oxygen that they may encounter in their natural environment, thereby contributing to their aerotolerance. This study lays the foundation for the first molecular, single-cell assay that will address factors that cannot otherwise be resolved in bulk assays and that will allow visualization of a wide range of molecular mechanisms within living anaerobic cells.

  5. Single-Cell Analysis of Growth and Cell Division of the Anaerobe Desulfovibrio vulgaris Hildenborough

    PubMed Central

    Fievet, Anouchka; Ducret, Adrien; Mignot, Tâm; Valette, Odile; Robert, Lydia; Pardoux, Romain; Dolla, Alain R.; Aubert, Corinne

    2015-01-01

    Recent years have seen significant progress in understanding basic bacterial cell cycle properties such as cell growth and cell division. While characterization and regulation of bacterial cell cycle is quite well-documented in the case of fast growing aerobic model organisms, no data has been so far reported for anaerobic bacteria. This lack of information in anaerobic microorganisms can mainly be explained by the absence of molecular and cellular tools such as single cell microscopy and fluorescent probes usable for anaerobes and essential to study cellular events and/or subcellular localization of the actors involved in cell cycle. In this study, single-cell microscopy has been adapted to study for the first time, in real time, the cell cycle of a bacterial anaerobe, Desulfovibrio vulgaris Hildenborough (DvH). This single-cell analysis provides mechanistic insights into the cell division cycle of DvH, which seems to be governed by the recently discussed so-called incremental model that generates remarkably homogeneous cell sizes. Furthermore, cell division was reversibly blocked during oxygen exposure. This may constitute a strategy for anaerobic cells to cope with transient exposure to oxygen that they may encounter in their natural environment, thereby contributing to their aerotolerance. This study lays the foundation for the first molecular, single-cell assay that will address factors that cannot otherwise be resolved in bulk assays and that will allow visualization of a wide range of molecular mechanisms within living anaerobic cells. PMID:26696987

  6. Biomineralization mediated by anaerobic methane-consuming cell consortia.

    PubMed

    Chen, Ying; Li, Yi-Liang; Zhou, Gen-Tao; Li, Han; Lin, Yang-Ting; Xiao, Xiang; Wang, Feng-Ping

    2014-07-16

    Anaerobic methanotrophic archaea (ANME) play a significant role in global carbon cycles. These organisms consume more than 90% of ocean-derived methane and influence the landscape of the seafloor by stimulating the formation of carbonates. ANME frequently form cell consortia with sulfate-reducing bacteria (SRB) of the family Deltaproteobacteria. We investigated the mechanistic link between ANME and the natural consortium by examining anaerobic oxidation of methane (AOM) metabolism and the deposition of biogenetic minerals through high-resolution imaging analysis. All of the cell consortia found in a sample of marine sediment were encrusted by a thick siliceous envelope consisting of laminated and cementing substances, whereas carbonate minerals were not found attached to cells. Beside SRB cells, other bacteria (such as Betaproteobacteria) were found to link with the consortia by adhering to the siliceous crusts. Given the properties of siliceous minerals, we hypothesize that ANME cell consortia can interact with other microorganisms and their substrates via their siliceous envelope, and this mechanism of silicon accumulation may serve in clay mineral formation in marine sedimentary environments. A mechanism for biomineralization mediated by AOM consortia was suggested based on the above observations.

  7. Facilitated cell export and desorption of methylmercury by anaerobic bacteria

    NASA Astrophysics Data System (ADS)

    Gu, B.; Lu, X.; Liu, Y.; Lin, H.

    2015-12-01

    Neurotoxic methylmercury (MeHg), formed by certain anaerobic bacteria, is shown to be rapidly excreted from the cell, but the mechanism of this process is unclear. Using both G. sulfurreducens PCA and D. desulfuricans ND132 strains, we investigated the factors affecting export and distribution of MeHg in mercury [Hg(II)] methylation as well as MeHg sorption and desorption assays. Thiols, such as cysteine, were found to greatly facilitate desorption and export of MeHg, particularly by G. sulfurreducens PCA cells. In short-term cysteine-free assays, we found that >90% of the synthesized MeHg was associated with PCA, among which ~73% was sorbed on the cell surface and 19% remained inside the cells, leaving only a small fraction in the phosphate buffered solution. However, MeHg export by PCA increased with increasing cysteine concentrations (0.05-50 mM), and nearly 100% of the MeHg was in solution in the presence of 50 mM cysteine. In comparison, ND132 cells were much more efficient than PCA in producing and exporting MeHg. In the absence of cysteine, a majority of the MeHg (~70%) was exported in 4 h, leaving about 20% of the MeHg sorbed on the surface and 10% inside the cells. When MeHg was directly added to the cell suspensions, ND132 adsorbed much lower MeHg than PCA cells; however, ND132 cells took up more MeHg (20%) inside cells than PCA did (8%). Taken together, our results demonstrate that MeHg export efficiency is bacteria strain-specific and is influenced by the ligand concentration and complexation, which could be important in facilitating MeHg synthesis and bioavailability in anoxic water and sediments.

  8. Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells.

    PubMed

    Wunsch, Christopher M; Lewis, Janina P

    2015-12-17

    Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth. The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2',7'-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal

  9. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    EPA Science Inventory

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  10. Transient proton inflows during illumination of anaerobic Halobacterium halobium cells

    NASA Technical Reports Server (NTRS)

    Helgerson, S. L.; Stoeckenius, W.

    1985-01-01

    The roles of bacteriorhodopsin (bR), halorhodopsin (hR), and the H(+)-ATPase in the proton uptake in intact cells are examined. The Halobacterium halobium strains and solutions utilized in the experiment, and the techniques for measuring extracellular pH changes and intracellular K(+) concentrations are described. It is observed that in Halobacterium halobium strain R1, containing bR and hR, the light-driven proton uptake is divided into three transient inflows superimposed on the larger proton outflow. Under anaerobic conditions early proton uptake consists of an inflow which can be blocked with Dio-9 and a second inflow that can be eliminated by low concentrations (less than 125 nm) of triphenyltin chloride (TPT). The effects of Dio-9 and TPT on the passive proton-hydroxyl permeability of the cell membrane are investigated. A third transient light-driven proton flow observed at later times of illumination is studied. The data reveal that the first proton inflow correlates with proton dependent ATP synthesis; the second inflow is a passive uptake through an unidentified channel in response to electrogenic chloride pumping by bR and/or hR; and the third inflow correlates with the Na(+)/H(+) antiporter function.

  11. Plasmodesmal-mediated cell-to-cell transport in wheat roots is modulated by anaerobic stress

    NASA Technical Reports Server (NTRS)

    Cleland, R. E.; Fujiwara, T.; Lucas, W. J.

    1994-01-01

    Cell-to-cell transport of small molecules and ions occurs in plants through plasmodesmata. Plant roots are frequently subjected to localized anaerobic stress, with a resultant decrease in ATP. In order to determine the effect of this stress on plasmodesmal transport, fluorescent dyes of increasing molecular weight (0.46 to 1OkDa) were injected into epidermal and cortical cells of 3-day-old wheat roots, and their movement into neighboring cells was determined by fluorescence microscopy. Anaerobiosis was generated by N2 gas or simulated by the presence of sodium azide, both of which reduced the ATP levels in the tissue by over 80%. In the absence of such stress, the upper limit for movement, or size exclusion limit (SEL), of cortical plasmodesmata was <1 kDa. The ATP analogue TNP-ADP (mw 681) moved across the plasmodesmata of unstressed roots, indicating that plasmodesmata may be conduits for nucleotide (ATP and ADP) exchange between cells. Upon imposition of stress, the SEL rose to between 5 and 10 kDa. This response of plasmodesmata to a decrease in the level of ATP suggests that they are constricted by an ATP-dependent process so as to maintain a restricted SEL. When roots are subjected to anaerobic stress, an increase in SEL may permit enhanced delivery of sugars to the affected cells of the root where anaerobic respiration could regenerate the needed ATP.

  12. Effective ammonium removal by anaerobic oxidation in microbial fuel cells.

    PubMed

    Jadhav, Dipak A; Ghangrekar, Makarand M

    2015-01-01

    Dual-chamber microbial fuel cells (MFCs), made of clayware cylinder, were operated at different chemical oxygen demands: ammonium-nitrogen (COD:NH4+) ratio (1:1, 10:1 and 5:1) under batch mode for simultaneous removal of ammonia and organic matter from wastewater. Ammonium-N removal efficiencies of 63-32.66% were obtained for COD:NH4+ ratio of 1:10, respectively. Average COD removal efficiencies demonstrated by these MFCs were about 88%; indicating effective use of MFCs for treatment of wastewater containing organic matter and high ammonia concentration. MFCs operated with COD:NH4+ ratio of 10:1 produced highest volumetric power density of 752.88 mW/m3. The ammonium-N removal slightly increased when microbes were exposed to only ammonium as a source of electron when organic source was not supplemented. When this MFC was operated with imposed potential on cathode and without aeration in the cathode chamber, oxidation of ammonium ions at a faster rate confirmed anaerobic oxidation. During the non-turnover condition of cyclic voltammetry, MFC operated with COD:NH4+ ratio of 10:1 gave higher oxidative and reductive currents than MFC operated with COD:NH4+ ratio of 1:1 due to higher redox species. Successful application of such an anammox process for ammonium oxidation in MFCs will be useful for treatment of wastewater containing higher ammonium concentration and harvesting energy in the form of electricity.

  13. Anaerobic digestion of distillery spent wash: Influence of enzymatic pre-treatment of intact yeast cells.

    PubMed

    Mallick, P; Akunna, J C; Walker, G M

    2010-03-01

    The potential benefits of enzymatic digestion of intact yeast cells on anaerobic digestion of Scotch whisky distillery spent wash and pot ale were investigated. Various yeast cell wall hydrolytic enzymes were studied based on their effect on dissolution of cell wall glucan and mannoprotein. The synergistic activity of beta-glucanase and protease showed greater than 90% yeast cell digestion at 37 degrees C in 24h. The widely-used industrial enzyme papain showed 95% yeast cell digestion in spent wash at 1% enzyme concentration within 22h at 50 degrees C. Anaerobic digestion of pot ale residues containing intact yeast cells pre-treated with lytic enzymes showed COD reductions of 87%, compared with only 13% without enzymes. Similar results were observed with distillery spent wash centrate. The hydrolysis of intact yeast cells in distillery liquid residues was found to be a rate-limiting step in anaerobic treatment of such residues.

  14. Evaluation on direct interspecies electron transfer in anaerobic sludge digestion of microbial electrolysis cell.

    PubMed

    Zhao, Zisheng; Zhang, Yaobin; Quan, Xie; Zhao, Huimin

    2016-01-01

    Increase of methanogenesis in methane-producing microbial electrolysis cells (MECs) is frequently believed as a result of cathodic reduction of CO2. Recent studies indicated that this electromethanogenesis only accounted for a little part of methane production during anaerobic sludge digestion. Instead, direct interspecies electron transfer (DIET) possibly plays an important role in methane production. In this study, anaerobic digestion of sludge were investigated in a single-chamber MEC reactor, a carbon-felt supplemented reactor and a common anaerobic reactor to evaluate the effects of DIET on the sludge digestion. The results showed that adding carbon felt into the reactor increased 12.9% of methane production and 17.2% of sludge reduction. Imposing a voltage on the carbon felt further improved the digestion. Current calculation showed that the cathodic reduction only contributed to 27.5% of increased methane production. Microbial analysis indicated that DIET played an important role in the anaerobic sludge digestion in the MEC.

  15. Contribution of cell elongation to the biofilm formation of Pseudomonas aeruginosa during anaerobic respiration.

    PubMed

    Yoon, Mi Young; Lee, Kang-Mu; Park, Yongjin; Yoon, Sang Sun

    2011-01-18

    Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO(2) (-)) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process.

  16. Development of Electroactive and Anaerobic Ammonium-Oxidizing (Anammox) Biofilms from Digestate in Microbial Fuel Cells

    PubMed Central

    Di Domenico, Enea Gino; Petroni, Gianluca; Mancini, Daniele; Geri, Alberto; Palma, Luca Di; Ascenzioni, Fiorentina

    2015-01-01

    Microbial Fuel cells (MFCs) have been proposed for nutrient removal and energy recovery from different wastes. In this study the anaerobic digestate was used to feed H-type MFC reactors, one with a graphite anode preconditioned with Geobacter sulfurreducens and the other with an unconditioned graphite anode. The data demonstrate that the digestate acts as a carbon source, and even in the absence of anode preconditioning, electroactive bacteria colonise the anodic chamber, producing a maximum power density of 172.2 mW/m2. The carbon content was also reduced by up to 60%, while anaerobic ammonium oxidation (anammox) bacteria, which were found in the anodic compartment of the reactors, contributed to nitrogen removal from the digestate. Overall, these results demonstrate that MFCs can be used to recover anammox bacteria from natural sources, and it may represent a promising bioremediation unit in anaerobic digestor plants for the simultaneous nitrogen removal and electricity generation using digestate as substrate. PMID:26273609

  17. Development of Electroactive and Anaerobic Ammonium-Oxidizing (Anammox) Biofilms from Digestate in Microbial Fuel Cells.

    PubMed

    Di Domenico, Enea Gino; Petroni, Gianluca; Mancini, Daniele; Geri, Alberto; Di Palma, Luca; Ascenzioni, Fiorentina

    2015-01-01

    Microbial Fuel cells (MFCs) have been proposed for nutrient removal and energy recovery from different wastes. In this study the anaerobic digestate was used to feed H-type MFC reactors, one with a graphite anode preconditioned with Geobacter sulfurreducens and the other with an unconditioned graphite anode. The data demonstrate that the digestate acts as a carbon source, and even in the absence of anode preconditioning, electroactive bacteria colonise the anodic chamber, producing a maximum power density of 172.2 mW/m(2). The carbon content was also reduced by up to 60%, while anaerobic ammonium oxidation (anammox) bacteria, which were found in the anodic compartment of the reactors, contributed to nitrogen removal from the digestate. Overall, these results demonstrate that MFCs can be used to recover anammox bacteria from natural sources, and it may represent a promising bioremediation unit in anaerobic digestor plants for the simultaneous nitrogen removal and electricity generation using digestate as substrate.

  18. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator.

    PubMed

    Lam, Raymond H W; Kim, Min-Cheol; Thorsen, Todd

    2009-07-15

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen-nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated).

  19. Thermodynamics-based design of microbial cell factories for anaerobic product formation.

    PubMed

    Cueto-Rojas, Hugo F; van Maris, A J A; Wahl, S Aljoscha; Heijnen, J J

    2015-09-01

    The field of metabolic engineering has delivered new microbial cell factories and processes for the production of different compounds including biofuels, (di)carboxylic acids, alcohols, and amino acids. Most of these processes are aerobic, with few exceptions (e.g., alcoholic fermentation), and attention is focused on assembling a high-flux product pathway with a production limit usually set by the oxygen transfer rate. By contrast, anaerobic product synthesis offers significant benefits compared to aerobic systems: higher yields, less heat generation, reduced biomass production, and lower mechanical energy input, which can significantly reduce production costs. Using simple thermodynamic calculations, we demonstrate that many products can theoretically be produced under anaerobic conditions using several conventional and non-conventional substrates.

  20. Gene expression profiling of Corynebacterium glutamicum during Anaerobic nitrate respiration: induction of the SOS response for cell survival.

    PubMed

    Nishimura, Taku; Teramoto, Haruhiko; Inui, Masayuki; Yukawa, Hideaki

    2011-03-01

    The gene expression profile of Corynebacterium glutamicum under anaerobic nitrate respiration revealed marked differences in the expression levels of a number of genes involved in a variety of cellular functions, including carbon metabolism and respiratory electron transport chain, compared to the profile under aerobic conditions using DNA microarrays. Many SOS genes were upregulated by the shift from aerobic to anaerobic nitrate respiration. An elongated cell morphology, similar to that induced by the DivS-mediated suppression of cell division upon cell exposure to the DNA-damaging reagent mitomycin C, was observed in cells subjected to anaerobic nitrate respiration. None of these transcriptional and morphological differences were observed in a recA mutant strain lacking a functional RecA regulator of the SOS response. The recA mutant cells additionally showed significantly reduced viability compared to wild-type cells similarly grown under anaerobic nitrate respiration. These results suggest a role for the RecA-mediated SOS response in the ability of cells to survive any DNA damage that may result from anaerobic nitrate respiration in C. glutamicum.

  1. Concerning the role of cell lysis-cryptic growth in anaerobic side-stream reactors: the single-cell analysis of viable, dead and lysed bacteria.

    PubMed

    Foladori, P; Velho, V F; Costa, R H R; Bruni, L; Quaranta, A; Andreottola, G

    2015-05-01

    In the Anaerobic Side-Stream Reactor (ASSR), part of the return sludge undergoes alternating aerobic and anaerobic conditions with the aim of reducing sludge production. In this paper, viability, enzymatic activity, death and lysis of bacterial cells exposed to aerobic and anaerobic conditions for 16 d were investigated at single-cell level by flow cytometry, with the objective of contributing to the understanding of the mechanisms of sludge reduction in the ASSR systems. Results indicated that total and viable bacteria did not decrease during the anaerobic phase, indicating that anaerobiosis at ambient temperature does not produce a significant cell lysis. Bacteria decay and lysis occurred principally under aerobic conditions. The aerobic decay rate of total bacteria (bTB) was considered as the rate of generation of lysed bacteria. Values of bTB of 0.07-0.11 d(-1) were measured in anaerobic + aerobic sequence. The enzymatic activity was not particularly affected by the transition from anaerobiosis to aerobiosis. Large solubilisation of COD and NH4(+) was observed only under anaerobic conditions, as a consequence of hydrolysis of organic matter, but not due to cell lysis. The observations supported the proposal of two independent mechanisms contributing equally to sludge reduction: (1) under anaerobic conditions: sludge hydrolysis of non-bacterial material, (2) under aerobic conditions: bacterial cell lysis and oxidation of released biodegradable compounds.

  2. Limits to anaerobic energy and cytosolic concentration in the living cell

    NASA Astrophysics Data System (ADS)

    Paglietti, A.

    2015-11-01

    For many physical systems at any given temperature, the set of all states where the system's free energy reaches its largest value can be determined from the system's constitutive equations of internal energy and entropy, once a state of that set is known. Such an approach is fraught with complications when applied to a living cell, because the cell's cytosol contains thousands of solutes, and thus thousands of state variables, which makes determination of its state impractical. We show here that, when looking for the maximum energy that the cytosol can store and release, detailed information on cytosol composition is redundant. Compatibility with cell's life requires that a single variable that represents the overall concentration of cytosol solutes must fall between defined limits, which can be determined by dehydrating and overhydrating the cell to its maximum capacity. The same limits are shown to determine, in particular, the maximum amount of free energy that a cell can supply in fast anaerobic processes, starting from any given initial state. For a typical skeletal muscle in normal physiological conditions this energy, i.e., the maximum anaerobic capacity to do work, is calculated to be about 960 J per kg of muscular mass. Such energy decreases as the overall concentration of solutes in the cytosol is increased. Similar results apply to any kind of cell. They provide an essential tool to understand and control the macroscopic response of single cells and multicellular cellular tissues alike. The applications include sport physiology, cell aging, disease produced cell damage, drug absorption capacity, to mention the most obvious ones.

  3. Azo dye treatment with simultaneous electricity production in an anaerobic-aerobic sequential reactor and microbial fuel cell coupled system.

    PubMed

    Li, Zhongjian; Zhang, Xingwang; Lin, Jun; Han, Song; Lei, Lecheng

    2010-06-01

    A microbial fuel cell and anaerobic-aerobic sequential reactor coupled system was used for azo dye degradation with simultaneous electricity production. Electricity was produced during the co-metabolism process of glucose and azo dye. A microorganism cultured graphite-granular cathode effectively decreased the charge transfer resistance of the cathode and yielded higher power density. Operation parameters including glucose concentration and hydraulic retention time were optimized. The results indicated that recovering electricity during a sequential aerobic-anaerobic azo dye treatment process enhanced chemical oxygen demand removal and did not decrease azo dye removal. Moreover, UV-vis spectra and GC-MS illustrated that the azo bond was cleaved biologically in the anaerobic chamber and abiotically in the aerobic chamber. The toxic intermediates, aromatic amines, were removed by aerobic treatment. Our work demonstrated that the microbial fuel cell and sequential anode-cathode reactor coupled system could be applied to achieve electricity production with simultaneous azo dye degradation.

  4. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY

    EPA Science Inventory

    The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. The fuel cell is being used for this application becau...

  5. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS AT THE YONKERS, NY, WASTEWATER TREATMENT PLANT

    EPA Science Inventory

    The paper summarizes the results of a 2-year field test to assess the performance of a specially modified commercial phosphoric acid 200 kW fuel cell power plant to recover energy from anaerobic digester gas (ADG) which has been cleansed of contaminants (sulfur and halide compoun...

  6. Microcalorimetric study of the anaerobic growth of Escherichia coli: measurements of the affinity of whole cells for various energy substrates.

    PubMed Central

    Belaich, A; Belaich, J P

    1976-01-01

    Microcalorimetry has been used to determine the affinity of whole cells of Escherichia coli for glucose, galactose, fructose, and lactose. Anaerobic growth thermograms were analyzed, and the Km and Vmax values for these energy substrates were measured at pH 7.8. Results obtained with this technique using various organisms growing anaerobically on different sugars are compared. This comparison shows that in practically all cases the cellular rate of catabolic activity is a hyperbolic function of the energy substrate concentrations at low sugar concentrations. In some cases this technique also allows determination of kinetics at high sugar concentrations. PMID:1373

  7. Simultaneous anaerobic sulfide and nitrate removal coupled with electricity generation in Microbial Fuel Cell.

    PubMed

    Cai, Jing; Zheng, Ping; Zhang, Jiqiang; Xie, Zuofu; Li, Wei; Sun, Peide

    2013-02-01

    Two-chamber Microbial Fuel Cells (MFC) using graphite rods as electrodes were operated for simultaneous anaerobic sulfide and nitrate removal coupled with electricity generation. The MFC showed good ability to remove substrates. When the influent sulfide and nitrate concentrations were 780 mg/L and 135.49 mg/L, respectively, the removal percentages of sulfide and nitrate were higher than 90% and the main end products were nitrogen and sulfate. The MFC also showed good ability to generate electricity, and the voltage went up with the rise of influent substrate concentrations. When the external resistance was 1000 Ω, its highest steady voltage was 71 mV. Based on the linear relationship between the electrons released by substrates and accepted by electrode, it was concluded that the electricity generation was coupled with the substrate conversion in the MFC.

  8. Enhanced anaerobic digestion of organic contaminants containing diverse microbial population by combined microbial electrolysis cell (MEC) and anaerobic reactor under Fe(III) reducing conditions.

    PubMed

    Zhang, Jingxin; Zhang, Yaobin; Quan, Xie; Chen, Shuo; Afzal, Shahzad

    2013-05-01

    Microbial electrolysis cell (MEC) devices are efficient for wastewater treatment, but its application was limited due to low anode oxidation rate. The objective of this study was to improve anode performance of a MEC combined anaerobic reactor (R1) for high concentration industrial wastewater treatment via dosing Fe(OH)3. For the first 53 days without power, the addition of Fe(OH)3 in R1 enhanced the degradation of reactive brilliant red X-3B dye and sucrose. Applying a voltage of 0.8 V in R1 resulted in a higher decolorization and COD removal through driving the redox reactions at electrodes under Fe(III)-reducing conditions. Real-time PCR and enzyme activity analysis showed that the abundance and azoreductase activity of bacteria were improved in R1. Pyrosequencing revealed that dominant populations in anode biofilm and R1 were more diverse and abundant than the common anaerobic reactor (R2), and there was a significant distinction among anode film, R1 and R2 in microbial community structure.

  9. Direct production of organic acids from starch by cell surface-engineered Corynebacterium glutamicum in anaerobic conditions

    PubMed Central

    2013-01-01

    We produced organic acids, including lactate and succinate, directly from soluble starch under anaerobic conditions using high cell-density cultures of Corynebacterium glutamicum displaying α-amylase (AmyA) from Streptococcus bovis 148 on the cell surface. Notably, reactions performed under anaerobic conditions at 35 and 40°C, which are higher than the optimal growth temperature of 30°C, showed 32% and 19%, respectively, higher productivity of the organic acids lactate, succinate, and acetate compared to that at 30°C. However, α-amylase was not stably anchored and released into the medium from the cell surface during reactions at these higher temperatures, as demonstrated by the 61% and 85% decreases in activity, respectively, from baseline, compared to the only 8% decrease at 30°C. The AmyA-displaying C. glutamicum cells retained their starch-degrading capacity during five 10 h reaction cycles at 30°C, producing 107.8 g/l of total organic acids, including 88.9 g/l lactate and 14.0 g/l succinate. The applicability of cell surface-engineering technology for the production of organic acids from biomass by high cell-density cultures of C. glutamicum under anaerobic conditions was demonstrated. PMID:24342107

  10. The Pool of ADP and ATP Regulates Anaerobic Product Formation in Resting Cells of Lactococcus lactis

    PubMed Central

    Palmfeldt, Johan; Paese, Marco; Hahn-Hägerdal, Bärbel; van Niel, Ed W. J.

    2004-01-01

    Lactococcus lactis grows homofermentatively on glucose, while its growth on maltose under anaerobic conditions results in mixed acid product formation in which formate, acetate, and ethanol are formed in addition to lactate. Maltose was used as a carbon source to study mixed acid product formation as a function of the growth rate. In batch and nitrogen-limited chemostat cultures mixed acid product formation was shown to be linked to the growth rate, and homolactic fermentation occurred only in resting cells. Two of the four lactococcal strains investigated with maltose, L. lactis 65.1 and MG1363, showed more pronounced mixed acid product formation during growth than L. lactis ATCC 19435 or IL-1403. In resting cell experiments all four strains exhibited homolactic fermentation. In resting cells the intracellular concentrations of ADP, ATP, and fructose 1,6-bisphosphate were increased and the concentration of Pi was decreased compared with the concentrations in growing cells. Addition of an ionophore (monensin or valinomycin) to resting cultures of L. lactis 65.1 induced mixed acid product formation concomitant with decreases in the ADP, ATP, and fructose 1,6-bisphosphate concentrations. ADP and ATP were shown to inhibit glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alcohol dehydrogenase in vitro. Alcohol dehydrogenase was the most sensitive enzyme and was totally inhibited at an adenine nucleotide concentration of 16 mM, which is close to the sum of the intracellular concentrations of ADP and ATP of resting cells. This inhibition of alcohol dehydrogenase might be partially responsible for the homolactic behavior of resting cells. A hypothesis regarding the level of the ATP-ADP pool as a regulating mechanism for the glycolytic flux and product formation in L. lactis is discussed. PMID:15345435

  11. Anaerobic bacteria

    MedlinePlus

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  12. Mathematical model for microbial fuel cells with anodic biofilms and anaerobic digestion.

    PubMed

    Picioreanu, C; van Loosdrecht, M C M; Katuri, K P; Scott, K; Head, I M

    2008-01-01

    This study describes the integration of IWA's anaerobic digestion model (ADM1) within a computational model of microbial fuel cells (MFCs). Several populations of methanogenic and electroactive microorganisms coexist suspended in the anolyte and in the biofilm attached to the anode. A number of biological, chemical and electrochemical reactions occur in the bulk liquid, in the biofilm and at the electrode surface, involving glucose, organic acids, H2 and redox mediators. Model output includes the evolution in time of important measurable MFC parameters (current production, consumption of substrates, suspended and attached biomass growth). Two- and three-dimensional model simulations reveal the importance of current and biomass heterogeneous distribution over the planar anode surface. Voltage- and power-current characteristics can be calculated at different moments in time to evaluate the limiting regime in which the MFC operates. Finally, model simulations are compared with experimental results showing that, in a batch MFC, smaller electrical resistance of the circuit leads to selection of electroactive bacteria. Higher coulombic yields are so obtained because electrons from substrate are transferred to anode rather than following the methanogenesis pathway. In addition to higher currents, faster COD consumption rates are so achieved. The potential of this general modelling framework is in the understanding and design of more complex cases of wastewater-fed microbial fuel cells.

  13. Innovative self-powered submersible microbial electrolysis cell (SMEC) for biohydrogen production from anaerobic reactors.

    PubMed

    Zhang, Yifeng; Angelidaki, Irini

    2012-05-15

    A self-powered submersible microbial electrolysis cell (SMEC), in which a specially designed anode chamber and external electricity supply were not needed, was developed for in situ biohydrogen production from anaerobic reactors. In batch experiments, the hydrogen production rate reached 17.8 mL/L/d at the initial acetate concentration of 410 mg/L (5 mM), while the cathodic hydrogen recovery ( [Formula: see text] ) and overall systemic coulombic efficiency (CE(os)) were 93% and 28%, respectively, and the systemic hydrogen yield ( [Formula: see text] ) peaked at 1.27 mol-H(2)/mol-acetate. The hydrogen production increased along with acetate and buffer concentration. The highest hydrogen production rate of 32.2 mL/L/d and [Formula: see text] of 1.43 mol-H(2)/mol-acetate were achieved at 1640 mg/L (20 mM) acetate and 100 mM phosphate buffer. Further evaluation of the reactor under single electricity-generating or hydrogen-producing mode indicated that further improvement of voltage output and reduction of electron losses were essential for efficient hydrogen generation. In addition, alternate exchanging the electricity-assisting and hydrogen-producing function between the two cell units of the SMEC was found to be an effective approach to inhibit methanogens. Furthermore, 16S rRNA genes analysis showed that this special operation strategy resulted same microbial community structures in the anodic biofilms of the two cell units. The simple, compact and in situ applicable SMEC offers new opportunities for reactor design for a microbial electricity-assisted biohydrogen production system.

  14. Coupling of anaerobic digester and microbial fuel cell for COD removal and ammonia recovery.

    PubMed

    Kim, Taeyoung; An, Junyeong; Jang, Jae Kyung; Chang, In Seop

    2015-11-01

    Microbial fuel cells (MFCs) were investigated for use in removing total ammonia nitrogen (TAN) and residual COD from effluent digested in an anaerobic digester (AD) fed with actual swine wastewater for 32 days in batch mode. Cumulative COD removal in the AD was as high as 59,647±2096 mg/L (80.5% removed), whereas TAN removal in the AD was negligible at 296±116 mg-N/L (5.8% removed), causing a decrease in the COD/TAN ratio from 14.5 to 3.0. In a subsequent MFC system, 77.5% of TAN was removed at 36 days, leading to an increase in COD/TAN ratio from 4.6 to 8.1. As a result, the COD in the anode was further reduced from 19,319±417 mg/L to 7519±554 mg/L (61.1% removed). From these results, removing the TAN in MFCs was found to increase the COD/TAN ratio, with the COD being further degraded.

  15. Separation of competitive microorganisms using anaerobic membrane bioreactors as pretreatment to microbial electrochemical cells.

    PubMed

    Dhar, Bipro Ranjan; Gao, Yaohuan; Yeo, Hyeongu; Lee, Hyung-Sool

    2013-11-01

    Anaerobic membrane bioreactors (AnMBRs) as pretreatment to microbial electrochemical cells (MECs) were first assessed for improving energy recovery. A dual-chamber MEC was operated at hydraulic retention time (HRT) ranging from 1 to 8d, while operating conditions for an AnMBR were fixed. Current density was increased from 7.5 ± 0 to 14 ± 1A/m(2) membrane with increasing HRT. MEC tests with AnMBR permeate (mainly propionate and acetate) and propionate medium confirmed that propionate was fermented to acetate and hydrogen gas, and anode-respiring bacteria (ARB) utilized these fermentation products as substrate. Membrane separation in the AnMBR excluded fermenters and methanogens from the MEC, and thus no methane production was found in the MEC. The lack of fermenters, however, slowed down propionate fermentation rate, which limited current density in the MEC. To symphonize fermenters, H2-consumers, and ARB in biofilm anode is essential for improving current density, and COD removal.

  16. Performance of anaerobic fluidized membrane bioreactors using effluents of microbial fuel cells treating domestic wastewater.

    PubMed

    Kim, Kyoung-Yeol; Yang, Wulin; Ye, Yaoli; LaBarge, Nicole; Logan, Bruce E

    2016-05-01

    Anaerobic fluidized membrane bioreactors (AFMBRs) have been mainly developed as a post-treatment process to produce high quality effluent with very low energy consumption. The performance of an AFMBR was examined using the effluent from a microbial fuel cell (MFC) treating domestic wastewater, as a function of AFMBR hydraulic retention times (HRTs) and organic matter loading rates. The MFC-AFMBR achieved 89 ± 3% removal of the chemical oxygen demand (COD), with an effluent of 36 ± 6 mg-COD/L over 112 days operation. The AFMBR had very stable operation, with no significant changes in COD removal efficiencies, for HRTs ranging from 1.2 to 3.8h, although the effluent COD concentration increased with organic loading. Transmembrane pressure (TMP) was low, and could be maintained below 0.12 bar through solids removal. This study proved that the AFMBR could be operated with a short HRT but a low COD loading rate was required to achieve low effluent COD.

  17. Counteracting ammonia inhibition during anaerobic digestion by recovery using submersible microbial desalination cell.

    PubMed

    Zhang, Yifeng; Angelidaki, Irini

    2015-07-01

    Ammonia inhibition is one of the most frequent and serious problems in biogas plants. In this study, a novel hybrid system consisting of a submersible microbial desalination cell (SMDC) and a continuous stirred tank reactor (CSTR) was developed for counteracting ammonia inhibition during anaerobic digestion (AD) with simultaneous in situ ammonia recovery and electricity production. The SMDC was powered by acetate in a buffer solution, while synthetic ammonia-rich wastewater was used as the feeding of the CSTR. Under continuous operation, ammonia recovery rate of 86 g-N/m(2) /day and current density of 4.33 A/m(2) were achieved at steady-state condition. As a result, 112% extra biogas was produced due to ammonia recovery by the SMDC. High-throughput sequencing showed that ammonia recovery had an impact on the microbial community structures in the SMDC and CSTR. Considering the additional economic benefits of biogas enhancement and possible wastewater treatment, the SMDC may represent a cost-effective and environmentally friendly method for waste resources recovery and biomethanation of ammonia-rich residues.

  18. Remediation of acid mine drainage using microbial fuel cell based on sludge anaerobic fermentation.

    PubMed

    Peng, Xiang; Tang, Tianle; Zhu, Xiaoqiao; Jia, Gaohui; Ding, Yanran; Chen, Yawen; Yang, Yang; Tang, Wenhao

    2016-11-30

    The aim of this work is to utilize the microbial fuel cell for removing metals and sulfate from acid mine drainage using sewage sludge organics and simultaneous electricity generation. The enriched sulfate-reducing mixed culture was used as the cathodic biofilm and the sludge as the substrate. Under anaerobic conditions, 71.2% sulfate, 99.7% heavy metals, and 51.6% total chemical oxygen demand are removed at an electrode spacing of 4 cm and a sludge concentration of 30% (v/v) after 10-day treatment. A maximum power density of 51.3 mW/m(2) is obtained. Approximately 79.5% of the dissipated sulfate is converted to element sulfur or polysulfides. The sulfide concentration is kept at below 20 mg-S/L. The concentrations of heavy metals are in the range of 0.02-0.06 mg/L in the effluent, which are far below the levels required by Chinese legislation. Microbial community analysis reveals that sulfate-reducing bacteria in Desulfuromonadales are dominant on the cathodic biofilm at the end of experiments. This study shows the potential of synchronous degradation of residual sludge and treatment of AMD with electricity harvesting.

  19. Effects of ferric iron on the anaerobic treatment and microbial biodiversity in a coupled microbial electrolysis cell (MEC)--anaerobic reactor.

    PubMed

    Zhang, Jingxin; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2013-10-01

    Adding Fe(III) into a MEC - anaerobic reactor enhanced the degradation of organic matters. To clarify the respective effects of combining Fe(III) dosage and a MEC and Fe(III) dosage only on strengthening anaerobic digestion, three anaerobic reactors were operated in parallel: a MEC - anaerobic reactor with dosing Fe(OH)3 (R1), an anaerobic reactor with dosing Fe(OH)3 (R2) and a common anaerobic reactor (R3). With increasing influent COD from 1500 to 4000 mg/L, the COD removal in R1 was maintained at 88.3% under a voltage of 0.8 V, which was higher than that in reactor R2 and R3. When the power was cut off, the COD removal in R1 decreased by 5.9%. The addition of Fe(OH)3 enhanced both anaerobic digestion and anodic oxidation, resulting in the effective mineralization of volatile fatty acids (VFAs). The reduced Fe(II) combined with electric field resulted more extracellular polymeric substances (EPS) production. Quantitative real - time PCR showed a higher abundance of bacteria in the anodic biofilm and R1. Pyrosequencing and denaturing gradient gel electrophoresis (DGGE) analysis revealed that the dominant bacteria and archaea communities were richer and more abundant in the anode biofilm and R1.

  20. Analysis of organic compounds' degradation and electricity generation in anaerobic fluidized bed microbial fuel cell for coking wastewater treatment.

    PubMed

    Liu, Xinmin; Wu, Jianjun; Guo, Qingjie

    2017-02-22

    A single-chambered packing-type anaerobic fluidized microbial fuel cell (AFBMFC) with coking wastewater (CWW) as fuel was built to treat CWW, which not only has high treating efficiency, but also can convert organic matter in wastewater into electricity. AFBMFC was constructed by using anaerobic sludge that was domesticated as inoculation sludge, which was used to biochemically treat CWW. The organic compounds in CWW were extracted by liquid-liquid extraction step by step every day. The extraction phase was concentrated by a rotary evaporator and a nitrogen sweeping device and was analyzed by GC-MS. And the electricity-generation performances of AFBMFC were investigated. The results show that the composition of CWW was complicated, which mainly contains hydrocarbons, phenols, nitrogenous organic compounds, alcohols and aldehydes, esters and acids and so on. After a cycle of anaerobic biochemical treatment, the content of organic compounds in the effluent decreased significantly. After the treatment of AFBMFC, 99.9% phenols, 98.4% alcohol and aldehydes and 95.3% nitrogenous compounds were biodegraded. In the effluent, some new compounds (such as tricosane and dibutyl phthalate) were produced. The chemical oxygen demand (COD) of CWW decreased from 3372 to 559 mg/L in the closed-circuit microbial fuel cell, and the COD removal was 83.4 ± 1.0%. The maximum power density of AFBMFC was 2.13 ± 0.01 mW m(-2).

  1. Development and application of an enzymatic and cell flotation treatment for the recovery of viable microbial cells from environmental matrices such as anaerobic sludge.

    PubMed

    Braun, Florence; Hamelin, Jérôme; Gévaudan, Gaëlle; Patureau, Dominique

    2011-12-01

    Efficient dissociation of microorganisms from their aggregate matrix is required to study the microorganisms without interaction with their native environment (e.g., biofilms, flocs, granules, etc.) and to assess their community composition through the application of molecular or microscopy techniques. To this end, we combined enzymatic treatments and a cell extraction by density gradient to efficiently recover anaerobic microorganisms from urban wastewater treatment plant sludge. The enzymes employed (amylase, cellulase, DNase, and pectinase) as a pretreatment softly disintegrated the extrapolymeric substances (EPS) interlocked with the microorganisms. The potential damaging effects of the applied procedure on bacterial and archaeal communities were assessed by studying the variations in density (using quantitative PCR), diversity (using capillary electrophoresis single-strand conformation polymorphism fingerprinting [CE-SSCP]), and activity (using a standard anaerobic activity test) of the extracted microorganisms. The protocol preserved the general capacity of the microbial community to produce methane under anaerobic conditions and its diversity; particularly the archaeal community was not affected in terms of either density or structure. This cell extraction procedure from the matrix materials offers interesting perspectives for metabolic, microscopic, and molecular assays of microbial communities present in complex matrices constituted by bioaggregates or biofilms.

  2. Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

    PubMed

    Zhang, Yifeng; Angelidaki, Irini

    2015-02-01

    High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation.

  3. Removal of volatile fatty acids and ammonia recovery from unstable anaerobic digesters with a microbial electrolysis cell.

    PubMed

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-11-01

    Continuous assays with a microbial electrolysis cell (MEC) fed with digested pig slurry were performed to evaluate its stability and robustness to malfunction periods of an anaerobic digestion (AD) reactor and its feasibility as a strategy to recover ammonia. When performing punctual pulses of volatile fatty acids (VFA) in the anode compartment of the MEC, simulating a malfunction of the AD process, an increase in the current density was produced (up to 14 times, reaching values of 3500mAm(-2)) as a result of the added chemical oxygen demand (COD), especially when acetate was used. Furthermore, ammonium diffusion from the anode to the cathode compartment was enhanced and the removal efficiency achieved up to 60% during daily basis VFA pulses. An AD-MEC combined system has proven to be a robust and stable configuration to obtain a high quality effluent, with a lower organic and ammonium content.

  4. Overcoming organic and nitrogen overload in thermophilic anaerobic digestion of pig slurry by coupling a microbial electrolysis cell.

    PubMed

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-09-01

    The combination of the anaerobic digestion (AD) process with a microbial electrolysis cell (MEC) coupled to an ammonia stripping unit as a post-treatment was assessed both in series operation, to improve the quality of the effluent, and in loop configuration recirculating the effluent, to increase the AD robustness. The MEC allowed maintaining the chemical oxygen demand removal of the whole system of 46±5% despite the AD destabilization after doubling the organic and nitrogen loads, while recovering 40±3% of ammonia. The AD-MEC system, in loop configuration, helped to recover the AD (55% increase in methane productivity) and attained a more stable and robust operation. The microbial population assessment revealed an enhancement of AD methanogenic archaea numbers and a shift in eubacterial population. The AD-MEC combined system is a promising strategy for stabilizing AD against organic and nitrogen overloads, while improving the quality of the effluent and recovering nutrients for their reutilization.

  5. Rhizomicrobium electricum sp. nov., a facultatively anaerobic, fermentative, prosthecate bacterium isolated from a cellulose-fed microbial fuel cell.

    PubMed

    Kodama, Yumiko; Watanabe, Kazuya

    2011-08-01

    A facultatively anaerobic, prosthecate bacterium, strain Mfc52(T), was isolated from a microbial fuel cell inoculated with soil and fed with cellulose as the sole fuel. Cells were Gram-negative, non-spore-forming, straight or slightly curved rods, and some of them had one or two polar prosthecae (stalks). Cells reproduced by binary fission or by budding from mother cells having prosthecae. Strain Mfc52(T) fermented various sugars and produced lactate, acetate and fumarate. Ferric iron, nitrate, oxygen and fumarate served as electron acceptors, while sulfate and malate did not. Nitrate was reduced to nitrite. The DNA G+C content was 64.7 mol%. On the basis of 16S rRNA gene sequence phylogeny, strain Mfc52(T) was affiliated with the genus Rhizomicrobium in the class Alphaproteobacteria and most closely related to Rhizomicrobium palustre with a sequence similarity of 97 %. Based on these physiological and phylogenetic characteristics, the name Rhizomicrobium electricum sp. nov. is proposed; the type strain is Mfc52(T) ( = JCM 15089(T)  = KCTC 5806(T)).

  6. Studies on some characteristics of hydrogen production by cell-free extracts of rumen anaerobic bacteria.

    PubMed

    Joyner, A E; Winter, W T; Godbout, D M

    1977-03-01

    Hydrogen production was studied in the following rumen anaerobes: Bacteroides clostridiiformis, Butyrivibrio fibrisolvens, Enbacterium limosum, Fusobacterium necrophorum, Megasphaera elsdenii, Ruminococcus albus, and Ruminococcus flavefaciens. Clostridium pasteurianum and Escherichia coli were included for comparative purposes. Hydrogen production from dithionite, dithionite-reduced methyl viologen, pyruvate, and formate was determined. All species tested produced hydrogen from dithionite-reduce methyl viologen, but only C. pasteurianum, B. clostridiiformis, E. limosum, and M. elsdenii produced hydrogen from dithionite. All species except E. coli produced hydrogen from pyruvate, but activity was low or absent in extracts of E. limosum, F. necrophorum, R. albus, and R. flavefaciens unless methyl viologen was added. Hydrogen was produced from formate only by E. coli, B. clostridiiformis, E. limosum, F. necrophorum, and R. flavefaciens. Extracts were subjected to ultracentrifugation in an effort to determine the solubility of hydrogenase. The hydrogenase of all species except E. coli appeared to be soluble, although variable amounts of hydrogenase activity were detected in the pellet. Treatment of extracts of the rumen microbial species with DEAE-cellulose resulted in loss ofhydrogen production from pyruvate. Activity was restored by the addition of methyl viologen. It is concluded that hydrogen production in these rumen microorganisms is similar to that in the saccharolytic clostridia.

  7. Hydrogen Photoproduction by Nutrient-Deprived Chalamydomonas reinhardtii Cells Immobilized Within Thin Alginate Films Under Aerobic and Anaerobic Conditions

    SciTech Connect

    Kosourov, S. N.; Seibert, M.

    2009-01-01

    A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells, entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 2} depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O{sub 2} in the liquid and headspace and restrict O{sub 2} diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications.

  8. Bioelectricity generation in microbial fuel cell using natural microflora and isolated pure culture bacteria from anaerobic palm oil mill effluent sludge.

    PubMed

    Nor, Muhamad Hanif Md; Mubarak, Mohd Fahmi Muhammad; Elmi, Hassan Sh Abdirahman; Ibrahim, Norahim; Wahab, Mohd Firdaus Abdul; Ibrahim, Zaharah

    2015-08-01

    A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.

  9. Sodium Nitroprusside Changed The Metabolism of Mesenchymal Stem Cells to An Anaerobic State while Viability and Proliferation Remained Intact

    PubMed Central

    Pari, Sadiyeh; Abnosi, Mohammad Hussein; Pakyari, Reza

    2017-01-01

    Objective We used sodium nitroprusside (SNP), a nitric oxide (NO) releasing molecule, to understand its effect on viability and proliferation of rat bone marrow mesenchymal stem cells (BM-MSCs). Materials and Methods This experimental study evaluated the viability and morphology of MSCs in the presence of SNP (100 to 2000 µM) at 1, 5, and 15 hours. We chose the 100, 1000, and 2000 µM concentrations of SNP for one hour exposure for further analyses. Cell proliferation was investigated by the colony forming assay and population doubling number (PDN). Na+, K+, and Ca2+ levels as well as activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate transaminase (AST), and alanine transaminase (ALT) were measured. Results The viability of MSCs dose-dependently reduced from 750 µM at one hour and 250 µM at 5 and 15 hours. The 100 µM caused no change in viability, however we observed a reduction in the cytoplasmic area at 5 and 15 hours. This change was not observed at one hour. The one hour treatment with 100 µM of SNP reduced the mean colony numbers but not the diameter when the cells were incubated for 7 and 14 days. In addition, one hour treatment with 100 µM of SNP significantly reduced ALT, AST, and ALP activities whereas the activity of LDH increased when incubated for 24 hours. The same treatment caused an increase in Ca2+ and reduction in Na+ content. The 1000 and 2000 µM concentrations reduced all the factors except Ca2+ and LDH which increased. Conclusion The high dose of SNP, even for a short time, was toxic. The low dose was safe with respect to viability and proliferation, especially over a short time. However elevated LDH activity might increase anaerobic metabolism. PMID:28367425

  10. Unravelling the active microbial community in a thermophilic anaerobic digester-microbial electrolysis cell coupled system under different conditions.

    PubMed

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2017-03-01

    Thermophilic anaerobic digestion (AD) of pig slurry coupled to a microbial electrolysis cell (MEC) with a recirculation loop was studied at lab-scale as a strategy to increase AD stability when submitted to organic and nitrogen overloads. The system performance was studied, with the recirculation loop both connected and disconnected, in terms of AD methane production, chemical oxygen demand removal (COD) and volatile fatty acid (VFA) concentrations. Furthermore, the microbial population was quantitatively and qualitatively assessed through DNA and RNA-based qPCR and high throughput sequencing (MiSeq), respectively to identify the RNA-based active microbial populations from the total DNA-based microbial community composition both in the AD and MEC reactors under different operational conditions. Suppression of the recirculation loop reduced the AD COD removal efficiency (from 40% to 22%) and the methane production (from 0.32 to 0.03 m(3) m(-3) d(-1)). Restoring the recirculation loop led to a methane production of 0.55 m(3) m(-3) d(-1) concomitant with maximum MEC COD and ammonium removal efficiencies of 29% and 34%, respectively. Regarding microbial analysis, the composition of the AD and MEC anode populations differed from really active microorganisms. Desulfuromonadaceae was revealed as the most active family in the MEC (18%-19% of the RNA relative abundance), while hydrogenotrophic methanogens (Methanobacteriaceae) dominated the AD biomass.

  11. Biomethane recovery from Egeria densa in a microbial electrolysis cell-assisted anaerobic system: Performance and stability assessment.

    PubMed

    Zhen, Guangyin; Kobayashi, Takuro; Lu, Xueqin; Kumar, Gopalakrishnan; Xu, Kaiqin

    2016-04-01

    Renewable energy recovery from submerged aquatic plants such as Egeria densa (E. densa) via continuous anaerobic digestion (AD) represents a bottleneck because of process instability. Here, a single-chamber membrane-free microbial electrolysis cell (MEC) equipped with a pair of Ti/RuO2 mesh electrodes (i.e. the combined MEC-AD system) was implemented at different applied voltages (0-1.0 V) to evaluate the potential effects of bioelectrochemical stimulation on methane production and process stability of E. densa fermentation. The application of MEC effectively stabilized E. densa fermentation and upgraded overall process performance, especially solid matters removal. E. densa AD process was operated steadily throughout bioelectrochemical process without any signs of imbalance. The solubilization-removal of solid matters and methane conversion efficiency gradually increased with increasing applied voltage, with an average methane yield of approximately 248.2 ± 21.0 mL L(-1) d(-1) at 1.0 V. Whereas, the stability of the process became worse immediately once the external power was removed, with weaken solid matters removal along with methane output, evidencing the favorable and indispensable role in maintaining process stability. The stabilizing effect was further quantitatively demonstrated by statistical analysis using standard deviation (SD), coefficient of variance (CV) and box-plots. The syntrophic and win-win interactions between fermenting bacteria and electroactive bacteria might have contributed to the improved process stability and bioenergy recovery.

  12. Enrichment of anodic biofilm inoculated with anaerobic or aerobic sludge in single chambered air-cathode microbial fuel cells.

    PubMed

    Gao, Chongyang; Wang, Aijie; Wu, Wei-Min; Yin, Yalin; Zhao, Yang-Guo

    2014-09-01

    Aerobic sludge after anaerobic pretreatment and anaerobic sludge were separately used as inoculum to start up air-cathode single-chamber MFCs. Aerobic sludge-inoculated MFCs arrived at 0.27 V with a maximum power density of 5.79 W m(-3), while anaerobic sludge-inoculated MFCs reached 0.21 V with 3.66 W m(-3). Microbial analysis with DGGE profiling and high-throughput sequencing indicated that aerobic sludge contained more diverse bacterial populations than anaerobic sludge. Nitrospira species dominated in aerobic sludge, while anaerobic sludge was dominated by Desulfurella and Acidithiobacillus species. Microbial community structure and composition in anodic biofilms enriched, respectively from aerobic and anaerobic sludges tended gradually to be similar. Potentially exoelectrogenic Geobacter and Anaeromusa species, biofilm-forming Zoogloea and Acinetobacter species were abundant in both anodic biofilms. This study indicated that aerobic sludge performed better for MFCs startup, and the enrichment of anodic microbial consortium with different inocula but same substrate resulted in uniformity of functional microbial communities.

  13. Anaerobic Digestion.

    PubMed

    Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

    2017-04-09

    The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

  14. Evaluation by electron microscopy and anaerobic culture of types of rumen bacteria associated with digestion of forage cell walls.

    PubMed Central

    Akin, D E

    1980-01-01

    Different morphological types of rumen bacteria which degraded cell walls of forage grasses with various in vitro digestibilities were evaluated with electron microscopy. The majority of these bacteria (i.e., about 70% or more) consisted of two distinct types: (i) encapsulated cocci and (ii) irregularly shaped bacteria, resembling major fiber digesters found in the rumen. Each type was capable of degrading structurally intact cell walls. Differences (P less than or equal to 0.02) in the percent ratio of encapsulated cocci to irregularly shaped bacteria were observed between Bermuda grass and fescue; the ratio of encapsulated cocci to irregularly shaped bacteria between Bermuda grass and orchard grass was similar and variations were high. The proportion of irregularly shaped bacteria usually increased with increased time of digestion. Differences (P greater than 0.1) were not found in the percentage ratio of encapsulated cocci to irregularly shaped bacteria attached to specific tissue types in either Bermuda grass or fescue. However, encapsulated cocci tended to be more prevalent on sclerenchyma than other tissues in Bermuda grass, but less prevalent on sclerenchyma than other tissues in fescue. Transmission electron microscopy of tissue digestion of rapidly degraded orchard grass blades revealed that mesophyll, parenchyma bundle sheath, and parts of the epidermal cell wall apparently were degraded without direct attachment of bacteria although bacteria were near the cell walls undergoing digestion. Anaerobic growth studies showed that the total culturable bacteria developing on medium 10 and media containing carbohydrates similar to those in forage cell walls (i.e., pectin, xylan, and cellobiose) were 80% higher from rumen bacterial populations adapted in vitro to cell walls of orchard grass compared to those from Bermuda grass; the number of colonies from the orchard grass-adapted population was significantly (P less than or equal to 0.05) greater on the medium

  15. Anaerobic Thermophiles

    PubMed Central

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has

  16. Enhancing uniformity and overall quality of red cell concentrate with anaerobic storage

    PubMed Central

    Yoshida, Tatsuro; Blair, Abbejane; D'Alessandro, Angelo; Nemkov, Travis; Dioguardi, Michael; Silliman, Christopher C.; Dunham, Andrew

    2017-01-01

    Background Recent research focused on understanding stored red blood cell (RBC) quality has demonstrated high variability in measures of RBC function and health across units. Studies have historically linked this high variability to variations in processing, storage method, and age. More recently, a large number of studies have focused on differences in donor demographics, donor iron sufficiency, and genetic predisposition of the donor to poor storage, particularly through mechanisms of accelerated oxidative damage. A study was undertaken to evaluate a potential additional source of unit to unit variation in stored RBC: the role of variable percent oxygen saturation (%SO2) levels on blood quality parameters during storage. Materials and methods %SO2 data from 492 LR-RBC/AS-3 units used for internal and external collaborative research was included in the analysis. Whole blood units were processed into red blood cells, AS-3 added, leucocyte reduced, in compliance with American Association of Blood Banks guidelines. LR-RBC/AS-3 products were subsequently analysed for %SO2 levels within 3–24 hours of phlebotomy using a co-oximeter. Separately, to evaluate the impact of pre-storage as well as increasing levels of %SO2 during storage, a pool-and-split study was performed. Four units of LR-RBC/AS-3 were split 6 ways; “as is” (control), hyperoxygenated to more than 90%, and four levels of pre-storage %SO2. The units were periodically sampled up to 42 days and analysed for %SO2, pCO2, methaemoglobin, ATP, 2,3-BPG as well as with the metabolomics workflow. Results The measured mean %SO2 in LR-RBC/AS-3 within 24 hours of collection was 45.9±17.5% with (32.7–61.0 IQR). %SO2 in all products increased to approximately 95–100% in three weeks. Measured blood quality parameters including ATP, % haemolysis, methaemoglobin, oxidised lipids, and GSH/GSSG indicated suppressed cellular metabolism and increased red cell degradation in response to higher %SO2 levels. Discussion

  17. Anaerobic microbial fuel cell treating combined industrial wastewater: Correlation of electricity generation with pollutants.

    PubMed

    Abbasi, Umara; Jin, Wang; Pervez, Arshid; Bhatti, Zulfiqar Ahmad; Tariq, Madiha; Shaheen, Shahida; Iqbal, Akhtar; Mahmood, Qaisar

    2016-01-01

    Microbial fuel cell (MFC) is a new technology that not only generates energy but treats wastewater as well. A dual chamber MFC was operated under laboratory conditions. Wastewater samples from vegetable oil industries, metal works, glass and marble industries, chemical industries and combined industrial effluents were collected and each was treated for 98h in MFC. The treatment efficiency for COD in MFC was in range of 85-90% at hydraulic retention time (HRT) of 96h and had significant impact on wastewater treatment as well. The maximum voltage of 890mV was generated when vegetable oil industries discharge was treated with columbic efficiency of 5184.7C. The minimum voltage was produced by Glass House wastewater which was 520mV. There was positive significant co-relation between COD concentration and generated voltage. Further research should be focused on the organic contents of wastewater and various ionic species affecting voltage generation in MFC.

  18. Effect of cathode electron acceptors on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell.

    PubMed

    Cai, Jing; Zheng, Ping; Mahmood, Qaisar

    2016-01-01

    The current investigation reports the effect of cathode electron acceptors on simultaneous sulfide and nitrate removal in two-chamber microbial fuel cells (MFCs). Potassium permanganate and potassium ferricyanide were common cathode electron acceptors and evaluated for substrate removal and electricity generation. The abiotic MFCs produced electricity through spontaneous electrochemical oxidation of sulfide. In comparison with abiotic MFC, the biotic MFC showed better ability for simultaneous nitrate and sulfide removal along with electricity generation. Keeping external resistance of 1,000 Ω, both MFCs showed good capacities for substrate removal where nitrogen and sulfate were the main end products. The steady voltage with potassium permanganate electrodes was nearly twice that of with potassium ferricyanide. Cyclic voltammetry curves confirmed that the potassium permanganate had higher catalytic activity than potassium ferricyanide. The potassium permanganate may be a suitable choice as cathode electron acceptor for enhanced electricity generation during simultaneous treatment of sulfide and nitrate in MFCs.

  19. Effect of operating modes on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell.

    PubMed

    Cai, Jing; Zheng, Ping; Qaisar, Mahmood; Xing, Yajuan

    2014-05-01

    The effect of operating modes on the simultaneous sulfide and nitrate removal were studied in two-chamber microbial fuel cells (MFCs). The batch and continuous operating modes were compared and evaluated in terms of substrate removal and electricity generation. Upon gradual increase in the influent sulfide concentration from 60 to 1,020 S mg L(-1), and the hydraulic retention time decrease from 17.2 to 6 h, the MFC accomplished a good substrate removal efficiency whereby nitrogen and sulfate were the main end products. The removal efficiency of the MFC in the continuous mode was much higher than that in the batch mode, and its current densities in the continuous mode were more stable and higher than in the batch mode, which could be explained by the linear relationship between electrons released by the substrates and accepted on the electrodes. The electricity output in the continuous mode of the MFC was higher than that in the batch mode. MFC's operation in the continuous mode was a better strategy for the simultaneous treatment of sulfide and nitrate.

  20. G(-) anaerobes-reactive CD4+ T-cells trigger RANKL-mediated enhanced alveolar bone loss in diabetic NOD mice.

    PubMed

    Mahamed, Deeqa A; Marleau, Annette; Alnaeeli, Mawadda; Singh, Bhagirath; Zhang, Xiaoxia; Penninger, Joseph M; Teng, Yen-Tung A

    2005-05-01

    Diabetic patients experience a higher risk for severe periodontitis; however, the underlying mechanism remains unclear. We investigated the contribution of antibacterial T-cell-mediated immunity to enhanced alveolar bone loss during periodontal infection in nonobese diabetic (NOD) mice by oral inoculation with Actinobacillus actinomycetemcomitans, a G(-) anaerobe responsible for juvenile and severe periodontitis. The results show that 1) inoculation with A. actinomycetemcomitans in pre-diabetic NOD mice does not alter the onset, incidence, and severity of diabetes; 2) after A. actinomycetemcomitans inoculation, diabetic NOD mice (blood glucose >200 mg/dl and with severe insulitis) exhibit significantly higher alveolar bone loss compared with pre-diabetic and nondiabetic NOD mice; and 3) A. actinomycetemcomitans-reactive CD4+ T-cells in diabetic mice exhibit significantly higher proliferation and receptor activator of nuclear factor kappaB ligand (RANKL) expression. When diabetic mice are treated with the RANKL antagonist osteoprotegerin (OPG), there is a significant reversal of alveolar bone loss, as well as reduced RANKL expression in A. actinomycetemcomitans-reactive CD4+ T-cells. This study clearly describes the impact of autoimmunity to anaerobic infection in an experimental periodontitis model of type 1 diabetes. Thus, microorganism-reactive CD4+ T-cells and the RANKL-OPG axis provide the molecular basis of the advanced periodontal breakdown in diabetes and, therefore, OPG may hold therapeutic potential for treating bone loss in diabetic subjects at high risk.

  1. Aerobically respiring prokaryotic strains exhibit a broader temperature–pH–salinity space for cell division than anaerobically respiring and fermentative strains

    PubMed Central

    Harrison, Jesse P.; Dobinson, Luke; Freeman, Kenneth; McKenzie, Ross; Wyllie, Dale; Nixon, Sophie L.; Cockell, Charles S.

    2015-01-01

    Biological processes on the Earth operate within a parameter space that is constrained by physical and chemical extremes. Aerobic respiration can result in adenosine triphosphate yields up to over an order of magnitude higher than those attained anaerobically and, under certain conditions, may enable microbial multiplication over a broader range of extremes than other modes of catabolism. We employed growth data published for 241 prokaryotic strains to compare temperature, pH and salinity values for cell division between aerobically and anaerobically metabolizing taxa. Isolates employing oxygen as the terminal electron acceptor exhibited a considerably more extensive three-dimensional phase space for cell division (90% of the total volume) than taxa using other inorganic substrates or organic compounds as the electron acceptor (15% and 28% of the total volume, respectively), with all groups differing in their growth characteristics. Understanding the mechanistic basis of these differences will require integration of research into microbial ecology, physiology and energetics, with a focus on global-scale processes. Critical knowledge gaps include the combined impacts of diverse stress parameters on Gibbs energy yields and rates of microbial activity, interactions between cellular energetics and adaptations to extremes, and relating laboratory-based data to in situ limits for cell division. PMID:26354829

  2. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    NASA Astrophysics Data System (ADS)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  3. Livestock Anaerobic Digester Database

    EPA Pesticide Factsheets

    The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

  4. Performance of a microbial fuel cell-based biosensor for online monitoring in an integrated system combining microbial fuel cell and upflow anaerobic sludge bed reactor.

    PubMed

    Jia, Hui; Yang, Guang; Wang, Jie; Ngo, Huu Hao; Guo, Wenshan; Zhang, Hongwei; Zhang, Xinbo

    2016-10-01

    A hybrid system integrating a microbial fuel cell (MFC)-based biosensor with upflow anaerobic sludge blanket (UASB) was investigated for real-time online monitoring of the internal operation of the UASB reactor. The features concerned were its rapidity and steadiness with a constant operation condition. In addition, the signal feedback mechanism was examined by the relationship between voltage and time point of changed COD concentration. The sensitivity of different concentrations was explored by comparing the signal feedback time point between the voltage and pH. Results showed that the electrical signal feedback was more sensitive than pH and the thresholds of sensitivity were S=3×10(-5)V/(mg/L) and S=8×10(-5)V/(mg/L) in different concentration ranges, respectively. Although only 0.94% of the influent COD was translated into electricity and applied for biosensing, this integrated system indicated great potential without additional COD consumption for real-time monitoring.

  5. Persistence and cell culturability of biocontrol strain Pseudomonas fluorescens CHA0 under plough pan conditions in soil and influence of the anaerobic regulator gene anr.

    PubMed

    Mascher, Fabio; Schnider-Keel, Ursula; Haas, Dieter; Défago, Geneviève; Moënne-Loccoz, Yvan

    2003-02-01

    Certain fluorescent pseudomonads can protect plants from soil-borne pathogens, and it is important to understand how these biocontrol agents survive in soil. The persistence of the biocontrol strain Pseudomonas fluorescens CHA0-Rif under plough pan conditions was assessed in non-sterile soil microcosms by counting total cells (immunofluorescence microscopy), intact cells (BacLight membrane permeability test), viable cells (Kogure's substrate-responsiveness test) and culturable cells (colony counts on selective plates) of the inoculant. Viable but non-culturable cells of CHA0-Rif (106 cells g-1 soil) were found in flooded microcosms amended with fermentable organic matter, in which the soil redox potential was low (plough pan conditions), in agreement with previous observations of plough pan samples from a field inoculated with CHA0-Rif. However, viable but non-culturable cells were not found in unamended flooded, amended unflooded or unamended unflooded (i.e. control) microcosms, suggesting that such cells resulted from exposure of CHA0-Rif to a combination of low redox potential and oxygen limitation in soil. CHA0-Rif is strictly aerobic. Its anaerobic regulator ANR is activated by low oxygen concentrations and it controls production of the biocontrol metabolite hydrogen cyanide under microaerophilic conditions. Under plough pan conditions, an anr-deficient mutant of CHA0-Rif and its complemented derivative displayed the same persistence pattern as CHA0-Rif, indicating that anr was not implicated in the formation of viable but non-culturable cells of this strain at the plough pan.

  6. Anaerobic bioprocessing of organic wastes.

    PubMed

    Verstraete, W; de Beer, D; Pena, M; Lettinga, G; Lens, P

    1996-05-01

    Anaerobic digestion of dissolved, suspended and solid organics has rapidly evolved in the last decades but nevertheless still faces several scientific unknowns. In this review, some fundamentals of bacterial conversions and adhesion are addressed initially. It is argued in the light of ΔG-values of reactions, and in view of the minimum energy quantum per mol, that anaerobic syntrophs must have special survival strategies in order to support their existence: redistributing the available energy between the partners, reduced end-product fermentation reactions and special cell-to-cell physiological interactions. In terms of kinetics, it appears that both reaction rates and residual substrate thresholds are strongly related to minimum ΔG-values. These new fundamental insights open perspectives for efficient design and operation of anaerobic bioprocesses. Subsequently, an overview is given of the current anaerobic biotechnology. For treating wastewaters, a novel and high performance new system has been introduced during the last decade; the upflow anaerobic sludge blanket system (UASB). This reactor concept requires anaerobic consortia to grow in a dense and eco-physiologically well-organized way. The microbial principles of such granular sludge growth are presented. Using a thermodynamic approach, the formation of different types of aggregates is explained. The application of this bioprocess in worldwide wastewater treatment is indicated. Due to the long retention times of the active biomass, the UASB is also suitable for the development of bacterial consortia capable of degrading xenobiotics. Operating granular sludge reactors at high upflow velocities (5-6 m/h) in expanded granular sludge bed (EGSB) systems enlarges the application field to very low strength wastewaters (chemical oxygen demand < 1 g/l) and psychrophilic temperatures (10°C). For the treatment of organic suspensions, there is currently a tendency to evolve from the conventional mesophilic

  7. Anaerobic Metabolism of Indoleacetate

    PubMed Central

    Ebenau-Jehle, Christa; Thomas, Markus; Scharf, Gernot; Kockelkorn, Daniel; Knapp, Bettina; Schühle, Karola; Heider, Johann

    2012-01-01

    The anaerobic metabolism of indoleacetate (indole-3-acetic acid [IAA]) in the denitrifying betaproteobacterium Azoarcus evansii was studied. The strain oxidized IAA completely and grew with a generation time of 10 h. Enzyme activities that transformed IAA were present in the soluble cell fraction of IAA-grown cells but were 10-fold downregulated in cells grown on 2-aminobenzoate or benzoate. The transformation of IAA did not require molecular oxygen but required electron acceptors like NAD+ or artificial dyes. The first products identified were the enol and keto forms of 2-oxo-IAA. Later, polar products were observed, which could not yet be identified. The first steps likely consist of the anaerobic hydroxylation of the N-heterocyclic pyrrole ring to the enol form of 2-oxo-IAA, which is catalyzed by a molybdenum cofactor-containing dehydrogenase. This step is probably followed by the hydrolytic ring opening of the keto form, which is catalyzed by a hydantoinase-like enzyme. A comparison of the proteome of IAA- and benzoate-grown cells identified IAA-induced proteins. Owing to the high similarity of A. evansii with strain EbN1, whose genome is known, we identified a cluster of 14 genes that code for IAA-induced proteins involved in the early steps of IAA metabolism. These genes include a molybdenum cofactor-dependent dehydrogenase of the xanthine oxidase/aldehyde dehydrogenase family, a hydantoinase, a coenzyme A (CoA) ligase, a CoA transferase, a coenzyme B12-dependent mutase, an acyl-CoA dehydrogenase, a fusion protein of an enoyl-CoA hydratase and a 3-hydroxyacyl-CoA dehydrogenase, a beta-ketothiolase, and a periplasmic substrate binding protein for ABC transport as well as a transcriptional regulator of the GntR family. Five predicted enzymes form or act on CoA thioesters, indicating that soon after the initial oxidation of IAA and possibly ring opening, CoA thioesters are formed, and the carbon skeleton is rearranged, followed by a CoA-dependent thiolytic

  8. Characterization of anaerobic sulfite reduction by Salmonella typhimurium and purification of the anaerobically induced sulfite reductase

    SciTech Connect

    Hallenbeck, P.C. ); Clark, M.A.; Barrett, E.L. )

    1989-06-01

    Mutants of Salmonella typhimurium that lack the biosynthetic sulfite reductase (cysI and cysJ mutants) retain the ability to reduce sulfite for growth under anaerobic conditions. Here we report studies of sulfite reduction by a cysI mutant of S. typhimurium and purification of the associated anaerobic sulfite reductase. Sulfite reduction for anaerobic growth did not require a reducing atmosphere but was prevented by an argon atmosphere contaminated with air (<0.33%). It was also prevented by the presence of 0.1 mM nitrate. Anaerobic growth in liquid minimal medium, but not on agar, was found to require additions of trace amounts (10{sup {minus}7} M) of cysteine. Spontaneous mutants that grew under the argon contaminated with air also lost the requirement for 10{sup {minus}7}M cysteine for anaerobic growth in liquid. A role for sulfite reduction in anaerobic energy generation was contraindicated by the findings that sulfite reduction did not improve cell yields, and anaerobic sulfite reductase activity was greatest during the stationary phase of growth. Sulfite reductase was purified from the cytoplasmic fraction of the anaerobically grown cysI mutant and was purified 190-fold. The most effective donor in crude extracts was NADH. NADHP and methyl viologen were, respectively, 40 and 30% as effective as NADH. Oxygen reversibly inhibited the enzyme. The anaerobic sulfite reductase showed some resemblance to the biosynthetic sulfite reductase, but apparently it has a unique, as yet unidentified function.

  9. Transcriptomic and Physiological Insights into the Robustness of Long Filamentous Cells of Methanosaeta harundinacea, Prevalent in Upflow Anaerobic Sludge Blanket Granules

    PubMed Central

    Zhou, Liguang; Yu, Haiying; Ai, Guomin; Zhang, Bo; Hu, Songnian

    2014-01-01

    Methanosaeta spp. are widely distributed in natural environments, and their filamentous cells contribute significantly to sludge granulation and the good performance of anaerobic reactors. A previous study indicated that Methanosaeta harundinacea 6Ac displays a quorum sensing-regulated morphological transition from short to long filaments, and more acetate is channeled into methane production in long filaments, whereas more is channeled into biomass synthesis in short filaments. Here, we performed transcriptomic and physiological analysis to gain insights into active methanogenesis in long filaments of M. harundinacea 6Ac. Both RNA sequencing (RNA-seq) and quantitative reverse transcription-PCR indicated that transcription of the genes involved in aceticlastic methanogenesis and energy metabolism was upregulated 1.2- to 10.3-fold in long filaments, while transcription of the genes for the methyl oxidative shunt was upregulated in short filaments. [2-13C]acetate trace experiments demonstrated that a relatively higher portion of the acetate methyl group was oxidized to CO2 in short filaments than in long filaments. The long filaments exhibited higher catalase activity and oxygen tolerance than the short ones, which is consistent with increased transcription of the oxidant-scavenging genes. Moreover, transcription of genes for cell surface structures was upregulated in the long filaments, and transmission electron microscopy revealed a thicker cell envelope in the filaments. RNA-seq determined a >2-fold upregulation of a variety of antistress genes in short filaments, like those encoding chaperones and DNA repair systems, which implies that the short filaments can be stressed. This study reveals the genetic basis for the prevalence of the long filamentous morphology of M. harundinacea cells in upflow anaerobic sludge blanket granules. PMID:25398869

  10. Transcriptomic and physiological insights into the robustness of long filamentous cells of Methanosaeta harundinacea, prevalent in upflow anaerobic sludge blanket granules.

    PubMed

    Zhou, Liguang; Yu, Haiying; Ai, Guomin; Zhang, Bo; Hu, Songnian; Dong, Xiuzhu

    2015-02-01

    Methanosaeta spp. are widely distributed in natural environments, and their filamentous cells contribute significantly to sludge granulation and the good performance of anaerobic reactors. A previous study indicated that Methanosaeta harundinacea 6Ac displays a quorum sensing-regulated morphological transition from short to long filaments, and more acetate is channeled into methane production in long filaments, whereas more is channeled into biomass synthesis in short filaments. Here, we performed transcriptomic and physiological analysis to gain insights into active methanogenesis in long filaments of M. harundinacea 6Ac. Both RNA sequencing (RNA-seq) and quantitative reverse transcription-PCR indicated that transcription of the genes involved in aceticlastic methanogenesis and energy metabolism was upregulated 1.2- to 10.3-fold in long filaments, while transcription of the genes for the methyl oxidative shunt was upregulated in short filaments. [2-(13)C]acetate trace experiments demonstrated that a relatively higher portion of the acetate methyl group was oxidized to CO2 in short filaments than in long filaments. The long filaments exhibited higher catalase activity and oxygen tolerance than the short ones, which is consistent with increased transcription of the oxidant-scavenging genes. Moreover, transcription of genes for cell surface structures was upregulated in the long filaments, and transmission electron microscopy revealed a thicker cell envelope in the filaments. RNA-seq determined a >2-fold upregulation of a variety of antistress genes in short filaments, like those encoding chaperones and DNA repair systems, which implies that the short filaments can be stressed. This study reveals the genetic basis for the prevalence of the long filamentous morphology of M. harundinacea cells in upflow anaerobic sludge blanket granules.

  11. Integrating microbial fuel cells with anaerobic acidification and forward osmosis membrane for enhancing bio-electricity and water recovery from low-strength wastewater.

    PubMed

    Liu, Jinmeng; Wang, Xinhua; Wang, Zhiwei; Lu, Yuqin; Li, Xiufen; Ren, Yueping

    2017-03-01

    Microbial fuel cells (MFCs) and forward osmosis (FO) are two emerging technologies with great potential for energy-efficient wastewater treatment. In this study, anaerobic acidification and FO membrane were simultaneously integrated into an air-cathode MFC (AAFO-MFC) for enhancing bio-electricity and water recovery from low-strength wastewater. During a long-term operation of approximately 40 days, the AAFO-MFC system achieved a continuous and relatively stable power generation, and the maximum power density reached 4.38 W/m(3). The higher bio-electricity production in the AAFO-MFC system was mainly due to the accumulation of ethanol resulted from anaerobic acidification process and the rejection of FO membrane. In addition, a proper salinity environment in the system controlled by the addition of MF membrane enhanced the electricity production. Furthermore, the AAFO-MFC system produced a high quality effluent, with the removal rates of organic matters and total phosphorus of more than 97%. However, the nitrogen removal was limited for the lower rejection of FO membrane. The combined biofouling and inorganic fouling were responsible for the lower water flux of FO membrane, and the Desulfuromonas sp. utilized the ethanol for bio-electricity production was observed in the anode. These results substantially improve the prospects for simultaneous wastewater treatment and energy recovery, and further studies are needed to optimize the system integration and operating parameters.

  12. Enhanced methane production in an anaerobic digestion and microbial electrolysis cell coupled system with co-cultivation of Geobacter and Methanosarcina.

    PubMed

    Yin, Qi; Zhu, Xiaoyu; Zhan, Guoqiang; Bo, Tao; Yang, Yanfei; Tao, Yong; He, Xiaohong; Li, Daping; Yan, Zhiying

    2016-04-01

    The anaerobic digestion (AD) and microbial electrolysis cell (MEC) coupled system has been proved to be a promising process for biomethane production. In this paper, it was found that by co-cultivating Geobacter with Methanosarcina in an AD-MEC coupled system, methane yield was further increased by 24.1%, achieving to 360.2 mL/g-COD, which was comparable to the theoretical methane yield of an anaerobic digester. With the presence of Geobacter, the maximum chemical oxygen demand (COD) removal rate (216.8 mg COD/(L·hr)) and current density (304.3A/m(3)) were both increased by 1.3 and 1.8 fold compared to the previous study without Geobacter, resulting in overall energy efficiency reaching up to 74.6%. Community analysis demonstrated that Geobacter and Methanosarcina could coexist together in the biofilm, and the electrochemical activities of both were confirmed by cyclic voltammetry. Our study observed that the carbon dioxide content in total gas generated from the AD reactor with Geobacter was only half of that generated from the same reactor without Geobacter, suggesting that Methanosarcina may obtain the electron transferred from Geobacter for the reduction of carbon dioxide to methane. Taken together, Geobacter not only can improve the performance of the MEC system, but also can enhance methane production.

  13. Treatment of anaerobic digestate supernatant in microbial fuel cell coupled constructed wetlands: Evaluation of nitrogen removal, electricity generation, and bacterial community response.

    PubMed

    Wu, Shubiao; Lv, Tao; Lu, Qimin; Ajmal, Zeeshan; Dong, Renjie

    2017-02-15

    The objective of this study was to assess whether the improved configuration of vertical upflow constructed wetlands (CWs) coupled with aeration in the centre part and effluent recirculation can strengthen the treatment performance of high strength anaerobic digestate supernatant. Moreover, electricity generation and bacterial community characteristics were also examined. The results indicated that intermittent aeration in vertical upflow CWs significantly enhanced organic matter (>69%, 214-401g/m(2)d) and ammonium (>92%, 62-138g/m(2)d) removal, regardless of aeration position. However, the removal efficiency of total nitrogen (TN) was limited to 24%-40%. Effluent recirculation was examined to enhance TN removal up to 69% in the central aerated CW, as compared to 44% observed in the bottom aerated CW. Accordingly, significantly higher abundances of denitrifiers (nirK and nirS) and anaerobic ammonium oxidation bacteria (anammox) were found in the bottom layer of the central aerated CW. In addition, the central aerated CW coupled with effluent recirculation generated significantly higher electricity (maximum power density of 112mW/m(2)) than traditional bottom aerated CWs when integrated with a microbial fuel cell (MFC). Results confirmed the application potential of this new configuration of upflow CW integrated with central aeration and effluent recirculation.

  14. Effect of operating temperatures on the microbial community profiles in a high cell density hybrid anaerobic bioreactor.

    PubMed

    Kundu, Kankana; Sharma, Shilpi; Sreekrishnan, T R

    2012-08-01

    Lack of knowledge about the microbial consortia involved in wastewater treatment at different operating temperatures, is a major reason for failure of anaerobic reactors in field applications. Present study was undertaken to correlate performance of hybrid anaerobic reactors operating at different temperatures (37, 45 and 55 °C) to structures of archaeal and bacterial communities involved. Self-immobilized granules were developed in the reactors continuously fed with synthetic wastewater (10,000 mg COD l(-1)) and operated at an organic loading rate of 2.22 kg COD m(-3) day(-1) and hydraulic retention time of 5 days. The reactor operated at 37 °C showed the best performance as well as the most diverse microbial community revealed by PCR-denaturing gradient gel electrophoresis analysis using 16S rRNA gene amplicons. Sequences derived from reactors operating at higher temperatures revealed presence of different methanogens, but lesser diversity caused a drop in COD degradation capability of the system indicating successful operation at low loading conditions.

  15. Metabolic determinants in Listeria monocytogenes anaerobic listeriolysin O production.

    PubMed

    Wallace, Nathan; Newton, Eric; Abrams, Elizabeth; Zani, Ashley; Sun, Yvonne

    2017-03-13

    Listeria monocytogenes is a human pathogen and a facultative anaerobe. To better understand how anaerobic growth affects L. monocytogenes pathogenesis, we first showed that anaerobic growth led to decreased growth and changes in surface morphology. Moreover, compared to aerobically grown bacteria, anaerobically grown L. monocytogenes established higher level of invasion but decreased intracellular growth and actin polymerization in cultured cells. The production of listeriolysin O (LLO) was significantly lower in anaerobic cultures-a phenotype observed in wild type and isogenic mutants lacking transcriptional regulators SigB or CodY or harboring a constitutively active PrfA. To explore potential regulatory mechanisms, we established that the addition of central carbon metabolism intermediates, such as acetate, citrate, fumarate, pyruvate, lactate, and succinate, led to an increase in LLO activity in the anaerobic culture supernatant. These results highlight the regulatory role of central carbon metabolism in L. monocytogenes pathogenesis under anaerobic conditions.

  16. Constitutive expression of Campylobacter jejuni truncated hemoglobin CtrHb improves the growth of Escherichia coli cell under aerobic and anaerobic conditions.

    PubMed

    Yang, Jiang-Ke; Xiong, Wei; Xu, Li; Li, Jia; Zhao, Xiu-Ju

    2015-01-01

    Bacteria hemoglobin could bind to the oxygen, transfer it from the intracellular microenvironment to the respiration process and sustain the energy for the metabolism and reproduction of cells. Heterologous expression of bacteria hemoglobin gene could improve the capacity of the host on oxygen-capturing and allow it to grow even under microaerophilic condition. To develop a system based on hemoglobin to help bacteria cells overcome the oxygen shortage in fermentation, in this study, Campylobacter jejuni truncated hemoglobin (CtrHb) gene was synthesized and expressed under the control of constitutive expression promoters P2 and P(SPO1-II) in Escherichia coli. As showed by the growth curves of the two recombinants P2-CtrHb and P(SPO1-II)-CtrHb, constitutive expression of CtrHb improved cell growth under aerobic shaking-flasks, anaerobic capped-bottles and bioreactor conditions. According to the NMR analysis, this improvement might come from the expression of hemoglobin which could boost the metabolism of cells by supplying more oxygen to the respiratory chain processes. Through semi-quantitative RT-PCR and CO differential spectrum assays, we further discussed the connection between the growth patterns of the recombinants, the expression level of CtrHb and oxygen binding capacity of CtrHb in cells. Based on the growth patterns of these recombinants in bioreactor, a possible choice on different type of recombinants under specific fermentation conditions was also suggested in this study.

  17. Identification, distribution, and toxigenicity of obligate anaerobes in polluted waters.

    PubMed Central

    Daily, O P; Joseph, S W; Gillmore, J D; Colwell, R R; Seidler, R J

    1981-01-01

    A seasonal occurrence of obligately anaerobic bacteria, predominantly of the genera Bacteroides and Clostridium, in a polluted water site has been observed. The number of anaerobes varied from 1.8 X 10(3) cells/ml in the warmer months to 10 cells/ml in winter. Several isolates were toxigenic, indicating a potential human health hazard. PMID:7235706

  18. Anaerobic Degradation of the Benzene Nucleus by a Facultatively Anaerobic Microorganism1

    PubMed Central

    Taylor, Barrie F.; Campbell, William L.; Chinoy, Ira

    1970-01-01

    A bacterium was isolated by elective culture with p-hydroxybenzoate as substrate and nitrate as electron acceptor. It grew either aerobically or anaerobically, by nitrate respiration, on a range of aromatic compounds. The organism was identified as a pseudomonad and was given the trivial name Pseudomonas PN-1. Benzoate and p-hydroxybenzoate were metabolized aerobically via protocatechuate, followed by meta cleavage catalyzed by protocatechuic acid-4,5-oxygenase, to yield α-hydroxy-γ-carboxymuconic semialdehyde. Pseudomonas PN-1 grew rapidly on p-hydroxybenzoate under strictly anaerobic conditions, provided nitrate was present, even though protocatechuic acid-4,5-oxygenase was repressed. Suspensions of cells grown anaerobically on p-hydroxybenzoate oxidized benzoate with nitrate and produced 4 to 5 μmoles of CO2 per μmole of benzoate added; these cells did not oxidize benzoate aerobically. The patterns of the oxidation of aromatic substrates with oxygen or nitrate by cells grown aerobically or anaerobically on different aromatic compounds indicated that benzoate rather than protocatechuate was a key intermediate in the early stages of anaerobic metabolism. It was concluded that the pathway for the anaerobic breakdown of the aromatic ring is different and quite distinct from the aerobic pathway. Mechanisms for the anaerobic degradation of the benzene nucleus by Pseudomonas PN-1 are discussed. PMID:5419260

  19. Anaerobic thermophilic culture

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A newly discovered thermophilic anaerobe is described that was isolated in a biologically pure culture and designated Thermoanaerobacter ethanolicus ATCC 3/550. T. Ethanolicus is cultured in aqueous nutrient medium under anaerobic, thermophilic conditions and is used in a novel process for producing ethanol by subjecting carbohydrates, particularly the saccharides, to fermentation action of the new microorganism in a biologically pure culture.

  20. Anaerobic glycolysis and specific gravity of the red blood cells of rats exposed to pure oxygen at 600 torr.

    NASA Technical Reports Server (NTRS)

    Sabine, J. C.; Leon, H. A.

    1971-01-01

    Rats were exposed to 100% oxygen at 600 torr for up to 8 days. Highly significant increases in RBC anaerobic glycolysis occurred during the first 4 days of exposure and then subsided. Two significant peaks were found, one on days 1 and 2 and one on day 4. The first peak is attributed to reticulocytosis, which was maximal after 90 minutes and had disappeared by day 3. A second mechanism must account for the peak on day 4. An interpretation of the second peak is provided by existing evidence that selective removal of older RBCs occurs during the first few days of exposure to hypobaric oxygen, with maximum effect on day 4. Results in splenectomized, sham-operated and intact animals were indistinguishable from each other. A significant decrease in RBC specific gravity was found in exposed animals with spleens intact, but not in splenectomized animals. Theoretical aspects of age-related parameters as an aid to continuous detection and evaluation of changes in RBC populations are discussed.

  1. Anaerobic performance at altitude.

    PubMed

    Coudert, J

    1992-10-01

    Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax). Conflicting results are reported on anaerobic capacity evaluated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wmax measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7-10 s sprints (i.e. force-velocity test) which solicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance. In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease.

  2. Anaerobic Digestion and its Applications

    EPA Science Inventory

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  3. Examination of various cell culture techniques for co-incubation of virulent Treponema pallidum (Nichols I strain) under anaerobic conditions.

    PubMed Central

    Sandok, P L; Knight, S T; Jenkin, H M

    1976-01-01

    Treponema pallidum (Nichols virulent) was incubated with and without cells in cell culture medium reduced to -275 mV Ecal, pH 7.3, under deoxygenated conditions. Five to ten percent of the treponemes attached to cells and remained motile for at least 120 h in cell-treponeme systems of co-incubation. Virulent treponemes could be detected after 120 to 144 h in the supernatant fluids of cell-treponeme co-incubation cultures and in cell-free tubes containing medium harvested from aerobically cultivated mammalian cells. Medium supplemented with ox serum ultrafiltrate, pyruvate, and sodium thioglycolate and gas mixtures containing H2 and CO2 enhanced treponemal survival. Increases in treponemal numbers were observed using dark-field microscopy but were not substantiated using the rabbit lesion test. Continuous passage of the treponeme was not achieved in vitro. PMID:789395

  4. Degradative capacities and 16S rRNA-targeted whole-cell hybridization of sulfate-reducing bacteria in an anaerobic enrichment culture utilizing alkylbenzenes from crude oil.

    PubMed Central

    Rabus, R; Fukui, M; Wilkes, H; Widdle, F

    1996-01-01

    A mesophilic sulfate-reducing enrichment culture growing anaerobically on crude oil was used as a model system to study which nutritional types of sulfate-reducing bacteria may develop on original petroleum constituents in oil wells, tanks, and pipelines. Chemical analysis of oil hydrocarbons during growth revealed depletion of toluene and o-xylene within 1 month and of m-xylene, o-ethyltoluene, m-ethyltoluene, m-propyltoluene, and m-isopropyltoluene within approximately 2 months. In anaerobic counting series, the highest numbers of CFU (6 x 10(6) to 8 x 10(6) CFU ml-1) were obtained with toluene and benzoate. Almost the same numbers were obtained with lactate, a substrate often used for detection of the vibrio-shaped, incompletely oxidizing Desulfovibrio sp. In the present study, however, lactate yielded mostly colonies of oval to rod-shaped, completely oxidizing, sulfate-reducing bacteria which were able to grow slowly on toluene or crude oil. Desulfovibrio species were detected only at low numbers (3 x 10(5) CFU ml-1). In agreement with this finding, a fluorescently labeled, 16S rRNA-targeted oligonucleotide probe described in the literature as specific for members of the Desulfovibrionaceae (suggested family) hybridized only with a small portion (< 5%) of the cells in the enrichment culture. These results are consistent with the observation that known Desulfovibrio species do not utilize aromatic hydrocarbons, the predominant substrates in the enrichment culture. All known sulfate-reducing bacteria which utilize aromatic compounds belong to a separate branch, the Desulfobacteriaceae (suggested family). Most members of this family are complete oxidizers. For specific hybridization with members of this branch, the probe had to be modified by a nucleotide exchange. Indeed, this modified probe hybridized with more than 95% of the cells in the enrichment culture. The results show that completely oxidizing, alkylbenzene-utilizing sulfate-reducing bacteria rather than

  5. Anaerobic brain abscess

    PubMed Central

    Sudhaharan, Sukanya; Chavali, Padmasri

    2016-01-01

    Background and Objectives: Brain abscess remains a potentially fatal central nervous system (CNS) disease, especially in developing countries. Anaerobic abscess is difficult to diagnose because of cumbersome procedures associated with the isolation of anaerobes. Materials and Methods: This is a hospital-based retrospective microbiological analysis of 430 brain abscess materials (purulent aspirates and/or tissue), for anaerobic organisms, that were received between 1987–2014, by the Microbiology Laboratory in our Institute. Results: Culture showed growth of bacteria 116/430 (27%) of the cases of which anaerobes were isolated in 48/116 (41.1%) of the cases. Peptostreptococcus (51.4 %), was the predominant organism isolated in four cases followed by Bacteroides and Peptococcus species. Conclusion: Early diagnosis and detection of these organisms would help in the appropriate management of these patients. PMID:27307977

  6. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: UTC FUEL CELLS' PC25C POWER PLANT - GAS PROCESSING UNIT PERFORMANCE FOR ANAEROBIC DIGESTER GAS

    EPA Science Inventory

    Under EPA’s Environmental Technology Verification program, which provides objective and scientific third party analysis of new technology that can benefit the environment, a combined heat and power system based on the UTC Fuel Cell's PC25C Fuel Cell Power Plant was evaluated. The...

  7. Anaerobic respiration sustains mitochondrial membrane potential in a prolyl hydroxylase pathway-activated cancer cell line in a hypoxic microenvironment.

    PubMed

    Takahashi, Eiji; Sato, Michihiko

    2014-02-15

    To elucidate how tumor cells produce energy in oxygen-depleted microenvironments, we studied the possibility of mitochondrial electron transport without oxygen. We produced well-controlled oxygen gradients (ΔO2) in monolayer-cultured cells. We then visualized oxygen levels and mitochondrial membrane potential (ΔΦm) in individual cells by using the red shift of green fluorescent protein (GFP) fluorescence and a cationic fluorescent dye, respectively. In this two-dimensional tissue model, ΔΦm was abolished in cells >500 μm from the oxygen source [the anoxic front (AF)], indicating limitations in diffusional oxygen delivery. This result perfectly matched GFP-determined ΔO2. In cells pretreated with dimethyloxaloylglycine (DMOG), a prolyl hydroxylase domain-containing protein (PHD) inhibitor, the AF was expanded to 1,500-2,000 μm from the source. In these cells, tissue ΔO2 was substantially decreased, indicating that PHD pathway activation suppressed mitochondrial respiration. The expansion of the AF and the reduction of ΔO2 were much more prominent in a cancer cell line (Hep3B) than in the equivalent fibroblast-like cell line (COS-7). Hence, the results indicate that PHD pathway-activated cells can sustain ΔΦm, despite significantly decreased electron flux to complex IV. Complex II inhibition abolished the effect of DMOG in expanding the AF, although tissue ΔO2 remained shallow. Separate experiments demonstrated that complex II plays a substantial role in sustaining ΔΦm in DMOG-pretreated Hep3B cells with complex III inhibition. From these results, we conclude that PHD pathway activation can sustain ΔΦm in an otherwise anoxic microenvironment by decreasing tissue ΔO2 while activating oxygen-independent electron transport in mitochondria.

  8. Correlation between Phylogroups and Intracellular Proteomes of Propionibacterium acnes and Differences in the Protein Expression Profiles between Anaerobically and Aerobically Grown Cells

    PubMed Central

    Dekio, Itaru; Culak, Renata; Ball, Graham; Gharbia, Saheer; Shah, Haroun N.

    2013-01-01

    Propionibacterium acnes is one of the dominant commensals on the human skin and also an opportunistic pathogen in relation to acne, sarcoidosis, prostate cancer, and various infections. Recent investigations using housekeeping and virulence genes have revealed that the species consists of three major evolutionary clades (types I, II, and III). In order to investigate protein expression differences between these phylogroups, proteomic profiles of 21 strains of P. acnes were investigated. The proteins extracted from cells cultured under anaerobic and aerobic conditions were analysed using a SELDI-TOF mass spectrometer, high-resolution capillary gel electrophoresis, and LC-MS/ MS. The SELDI spectral profiles were visualised as a heat map and a dendrogram, which resulted in four proteomic groups. Strains belonging to type I were represented in the proteome Group A, while Group B contained type III strains. Groups C and D contained mixtures of types I and II. Each of these groups was not influenced by differences in culture conditions. Under anoxic growth conditions, a type IB strain yielded high expressions of some proteins, such as methylmalonyl-CoA epimerase and the Christie-Atkins-Munch-Petersen (CAMP) factor. The present study revealed good congruence between genomic and proteomic data suggesting that the microenvironment of each subtype may influence protein expression. PMID:23878795

  9. Optimization of wastewater feeding for single-cell protein production in an anaerobic wastewater treatment process utilizing purple non-sulfur bacteria in mixed culture condition.

    PubMed

    Honda, Ryo; Fukushi, Kensuke; Yamamoto, Kazuo

    2006-10-01

    Impacts of operation timing of feeding and withdrawal on anaerobic wastewater treatment utilizing purple non-sulfur bacteria have been investigated in mixed culture condition with acidogenic bacteria. Simulated wastewater containing glucose was treated in a laboratory-scale chemostat reactor, changing the timing of wastewater feeding and withdrawal. Rhodopseudomonas palustris, which does not utilize glucose as a substrate, was inoculated in the reactor. Rps. palustris was detected by a fluorescent in situ hybridization (FISH) technique using the specific Rpal686 probe. As a result, population ratios of Rps. palustris were over 20% through the operation. Rps. palustris could grow by utilizing metabolites of acidogenic bacteria that coexisted in the reactor. A morning feed was effective for a good growth of purple non-sulfur bacteria. A protein content of cultured bacteria was the highest when wastewater was fed in the morning. Dissolved organic carbon (DOC) removal was 94% independent of the timing control. Consequently, feeding in the morning is the optimum feed-timing control from the aspects of growth of purple non-sulfur bacteria and single-cell protein production.

  10. Features of Golenkinia sp. and microbial fuel cells used for the treatment of anaerobically digested effluent from kitchen waste at different dilutions.

    PubMed

    Hou, Qingjie; Cheng, Juan; Nie, Changliang; Pei, Haiyan; Jiang, Liqun; Zhang, Lijie; Yang, Zhigang

    2017-02-23

    The aim of this work was to study Golenkinia sp. and microbial fuel cells (MFCs) for the treatment of anaerobically digested effluent from kitchen waste (ADE-KW) with different dilution factors. A dual-chamber MFC was fabricated for treating ADE-KW in the two chambers of the MFC and harvesting Golenkinia sp. All the anodic TN was removed more than 80%. COD removal efficiency increased from 48.2% to 76% when the dilution factor increased from 1 to 4. Maximum COD and TN removal rates were 3.56 and 3.71mg·L(-1)·h(-1) when ADE-KW was treated without dilution in the anodic chamber. All the cathodic TN and TP removal efficiencies were approximately 90%. The highest open circuit voltage (OCV) and power density were approximately 400mV and 400mW when ADE-KW was treated directly (undiluted) in the MFC, with the highest biomass and total lipid content production of Golenkinia sp. in the cathodic chamber.

  11. Effect of mean cell residence time on transmembrane flux, mixed-liquor characteristics and overall performance of a submerged anaerobic membrane bioreactor.

    PubMed

    Pacheco-Ruiz, Santiago; Heaven, Sonia; Banks, Charles J

    2017-05-01

    Kinetic control of Mean Cell Residence Time (MCRT) was shown to have a significant impact on membrane flux under steady-state conditions. Two laboratory-scale flat-plate submerged anaerobic membrane bioreactors were operated for 245 days on a low-to-intermediate strength substrate with high suspended solids. Transmembrane pressure was maintained at 2.2 kPa throughout four experimental phases, while MCRT in one reactor was progressively reduced. This allowed very accurate measurement of sustainable membrane flux rates at different MCRTs, and hence the degree of membrane fouling. Performance data were gathered on chemical oxygen demand (COD) removal efficiency, and a COD mass balance was constructed accounting for carbon converted into new biomass and that lost in the effluent as dissolved methane. Measurements of growth yield at each MCRT were made, with physical characterisation of each mixed liquor based on capillary suction time. The results showed membrane flux and MLSS filterability was highest at short MCRT, although specific methane production (SMP) was lower since a proportion of COD removal was accounted for by higher biomass yield. There was no advantage in operating at an MCRT <25 days. When considering the most suitable MCRT there is thus a trade-off between membrane performance, SMP and waste sludge yield.

  12. Microbiological mechanism of the improved nitrogen and phosphorus removal by embedding microbial fuel cell in Anaerobic-Anoxic-Oxic wastewater treatment process.

    PubMed

    Xie, Beizhen; Liu, Bojie; Yi, Yue; Yang, Lige; Liang, Dawei; Zhu, Ying; Liu, Hong

    2016-05-01

    Anaerobic-Anoxic-Oxic (AA/O) wastewater treatment process is a widely used wastewater treatment process for simultaneous nitrogen and phosphorus removal. Microbial fuel cell (MFC) can generate electricity and treat the organic wastewater simultaneously. Our previous research showed that embedding MFC in AA/O wastewater treatment process could enhance the pollutants removal efficiency. However, the mechanism was not clear. In this study, a lab-scale corridor-style AA/O reactor with MFC embedded was operated and both the total nitrogen and total phosphorus removal efficiencies were enhanced. DGGE and Illumina Miseq results demonstrated that both the microbial community structures on the surface of the cathode and in the suspensions of cathode chamber have been changed. The percentage of Thauera and Emticicia, identified as denitrifying bacteria, increased significantly in the suspension liquid when the MFC was embedded in the AA/O reactor. Moreover, the genus Rheinheimera were significantly enriched on the cathode surface, which might contribute to both the nitrogen removal enhancement and electricity generation.

  13. Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

    PubMed

    Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

    2013-02-01

    Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.

  14. A two-stage microbial fuel cell and anaerobic fluidized bed membrane bioreactor (MFC-AFMBR) system for effective domestic wastewater treatment.

    PubMed

    Ren, Lijiao; Ahn, Yongtae; Logan, Bruce E

    2014-04-01

    Microbial fuel cells (MFCs) are a promising technology for energy-efficient domestic wastewater treatment, but the effluent quality has typically not been sufficient for discharge without further treatment. A two-stage laboratory-scale combined treatment process, consisting of microbial fuel cells and an anaerobic fluidized bed membrane bioreactor (MFC-AFMBR), was examined here to produce high quality effluent with minimal energy demands. The combined system was operated continuously for 50 days at room temperature (∼25 °C) with domestic wastewater having a total chemical oxygen demand (tCOD) of 210 ± 11 mg/L. At a combined hydraulic retention time (HRT) for both processes of 9 h, the effluent tCOD was reduced to 16 ± 3 mg/L (92.5% removal), and there was nearly complete removal of total suspended solids (TSS; from 45 ± 10 mg/L to <1 mg/L). The AFMBR was operated at a constant high permeate flux of 16 L/m(2)/h over 50 days, without the need or use of any membrane cleaning or backwashing. Total electrical energy required for the operation of the MFC-AFMBR system was 0.0186 kWh/m(3), which was slightly less than the electrical energy produced by the MFCs (0.0197 kWh/m(3)). The energy in the methane produced in the AFMBR was comparatively negligible (0.005 kWh/m(3)). These results show that a combined MFC-AFMBR system could be used to effectively treat domestic primary effluent at ambient temperatures, producing high effluent quality with low energy requirements.

  15. Gender comparisons in anaerobic power and anaerobic capacity tests.

    PubMed Central

    Maud, P J; Shultz, B B

    1986-01-01

    The purpose of the study was to compare anaerobic power and anaerobic capacity test scores between young active men and women. Three performance measures of anaerobic power and two of anaerobic capacity were administered to a sample comprising 52 male and 50 female college students (means age = 21.4 yrs). Results indicated significant differences between men and women in body height, weight and per cent fat, in fat free mass (FFM), anaerobic power, and anaerobic capacity when recorded as gross work completed and relative to body weight. However, these differences are reduced when data is adjusted for body weight and further reduced when corrected for FFM. The study found no significant differences between men and women in either anaerobic power or anaerobic capacity when values were given relative to FFM. PMID:3730753

  16. Microbial fuel cell using anaerobic respiration as an anodic reaction and biomineralized manganese as a cathodic reactant.

    PubMed

    Rhoads, Allison; Beyenal, Haluk; Lewandowski, Zbigniew

    2005-06-15

    We have operated a microbial fuel cell in which glucose was oxidized by Klebsiella pneumoniae in the anodic compartment, and biomineralized manganese oxides, deposited by Leptothrix discophora, were electrochemically reduced in the cathodic compartment. In the anodic compartment, to facilitate the electron transfer from glucose to the graphite electrode, we added a redox mediator, 2-hydroxy-1,4-naphthoquinone. We did not add any redox mediator to the cathodic compartment because the biomineralized manganese oxides were deposited on the surface of a graphite electrode and were reduced directly by electrons from the electrode. We have demonstrated that biomineralized manganese oxides are superiorto oxygen when used as cathodic reactants in microbial fuel cells. The current density delivered by using biomineralized manganese oxides as the cathodic reactant was almost 2 orders of magnitude higher than that delivered using oxygen. Several fuel cells were operated for 500 h, reaching anodic potentials of -441.5 +/- 31 mVscE and cathodic potentials of +384.5 +/- 64 mVscE. When the electrodes were connected by a 50 Ohms resistor, the fuel cell delivered the peak power density of 126.7 +/- 31.5 mW/m2.

  17. Fabrication of niobium-based oxides/oxynitrides/nitrides and their applications in dye-sensitized solar cells and anaerobic digestion

    NASA Astrophysics Data System (ADS)

    Zhang, Taihong; Yun, Sining; Li, Xue; Huang, Xinlei; Hou, Yuzhi; Liu, Yanfang; Li, Jing; Zhou, Xiao; Fang, Wen

    2017-02-01

    Transition metal compounds (TMCs), as a representative family of functional materials, have attracted great attention in the field of renewable energy. Herein, Nb3.49N4.56O0.44 and NbN are prepared from the nitridation of NbO2 in an NH3 atmosphere. These dual-functional Nb-based compounds were applied to dye-sensitized solar cells (DSSCs) and anaerobic digestion (AD), and the efficiency and stability of these DSSCs and AD systems were systematically evaluated. The Nb3.49N4.56O0.44 counter electrode (CE) exhibited considerable electrocatalytic activity and stability in I3- reduction in DSSCs, achieving photovoltaic performance comparable with Pt (6.36% vs. 7.19%). Furthermore, as accelerants, Nb-based compounds can greatly improve the AD environment, increasing substrate utilization and decreasing the hazards in the digestate. Compared with the control sample (409.2 mL/g·VS and 29.55%), substantially higher cumulative biogas production (437.1-522.7 mL/g·VS) and chemical oxygen demand removal rates (56.08%-65.19%) were achieved using Nb-based accelerants in the AD system. The nitridation technique is an effective and general means of converting Nb-based oxides into oxynitrides and nitrides. The Nb-based compounds with high electrocatalytic activities showed promise for DSSCs applications, while greatly enhancing the biodegradability of the AD system as accelerants. These findings could pave the way for multifunctional applications of TMCs in renewable energy fields.

  18. Anaerobic benzene oxidation by Geobacter species.

    PubMed

    Zhang, Tian; Bain, Timothy S; Nevin, Kelly P; Barlett, Melissa A; Lovley, Derek R

    2012-12-01

    The abundance of Geobacter species in contaminated aquifers in which benzene is anaerobically degraded has led to the suggestion that some Geobacter species might be capable of anaerobic benzene degradation, but this has never been documented. A strain of Geobacter, designated strain Ben, was isolated from sediments from the Fe(III)-reducing zone of a petroleum-contaminated aquifer in which there was significant capacity for anaerobic benzene oxidation. Strain Ben grew in a medium with benzene as the sole electron donor and Fe(III) oxide as the sole electron acceptor. Furthermore, additional evaluation of Geobacter metallireducens demonstrated that it could also grow in benzene-Fe(III) medium. In both strain Ben and G. metallireducens the stoichiometry of benzene metabolism and Fe(III) reduction was consistent with the oxidation of benzene to carbon dioxide with Fe(III) serving as the sole electron acceptor. With benzene as the electron donor, and Fe(III) oxide (strain Ben) or Fe(III) citrate (G. metallireducens) as the electron acceptor, the cell yields of strain Ben and G. metallireducens were 3.2 × 10(9) and 8.4 × 10(9) cells/mmol of Fe(III) reduced, respectively. Strain Ben also oxidized benzene with anthraquinone-2,6-disulfonate (AQDS) as the sole electron acceptor with cell yields of 5.9 × 10(9) cells/mmol of AQDS reduced. Strain Ben serves as model organism for the study of anaerobic benzene metabolism in petroleum-contaminated aquifers, and G. metallireducens is the first anaerobic benzene-degrading organism that can be genetically manipulated.

  19. Anaerobic thermophilic culture system

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A mixed culture system of the newly discovered microorganism Thermoanaerobacter ethanolicus ATCC31550 and the microorganism Clostridium thermocellum ATCC31549 is described. In a mixed nutrient culture medium that contains cellulose, these microorganisms have been coupled and cultivated to efficiently ferment cellulose to produce recoverable quantities of ethanol under anaerobic, thermophilic conditions.

  20. The anaerobic digestion process

    SciTech Connect

    Rivard, C.J.; Boone, D.R.

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  1. Electricity generation from cattle dung using microbial fuel cell technology during anaerobic acidogenesis and the development of microbial populations.

    PubMed

    Zhao, Guang; Ma, Fang; Wei, Li; Chua, Hong; Chang, Chein-Chi; Zhang, Xiao-Jun

    2012-09-01

    A microbial fuel cell (MFC) was constructed to investigate the possible generation of electricity using cattle dung as a substrate. After 30 days of operation, stable electricity was generated, and the maximum volumetric power density was 0.220 W/m(3). The total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of the MFC reached 73.9±1.8% and 2.79±0.6%, respectively, after 120 days of operation. Acetate was the main metabolite in the anolyte, and other volatile fatty acids (VFAs) (propionate and butyrate) were present in minor amounts. The PCR-DGGE analysis indicated that the following five groups of microbes were present: Proteobacteria, Bacteroides, Chloroflexi, Actinobacteria and Firmicutes. Proteobacteria and Firmicutes were the dominant phyla in the sample; specifically, 36.3% and 24.2% of the sequences obtained were Proteobacteria and Firmicutes, respectively. Clostridium sp., Pseudomonas luteola and Ochrobactrum pseudogrignonense were the most dominant groups during the electricity generation process. The diversity of archaea dramatically decreased after 20 days of operation. The detected archaea were hydrogenotrophic methanogens, and the Methanobacterium genus disappeared during the periods of stable electricity generation via acidogenesis.

  2. The effect of salinity, redox mediators and temperature on anaerobic biodegradation of petroleum hydrocarbons in microbial fuel cells.

    PubMed

    Adelaja, Oluwaseun; Keshavarz, Tajalli; Kyazze, Godfrey

    2015-01-01

    Microbial fuel cells (MFCs) need to be robust if they are to be applied in the field for bioremediation. This study investigated the effect of temperature (20-50°C), salinity (0.5-2.5% (w/v) as sodium chloride), the use of redox mediators (riboflavin and anthraquinone-2-sulphonate, AQS) and prolonged fed-batch operation (60 days) on biodegradation of a petroleum hydrocarbon mix (i.e. phenanthrene and benzene) in MFCs. The performance criteria were degradation efficiency, % COD removal and electrochemical performance. Good electrochemical and degradation performance were maintained up to a salinity of 1.5% (w/v) but deteriorated by 35-fold and 4-fold respectively as salinity was raised to 2.5%w/v. Degradation rates and maximum power density were both improved by approximately 2-fold at 40°C compared to MFC performance at 30°C but decreased sharply by 4-fold when operating temperature was raised to 50°C. The optimum reactor performance obtained at 40°C was 1.15 mW/m(2) maximum power density, 89.1% COD removal and a degradation efficiency of 97.10%; at moderately saline (1% w/v) conditions the maximum power density was 1.06 mW/m(2), 79.1% COD removal and 91.6% degradation efficiency. This work suggests the possible application of MFC technology in the effective treatment of petroleum hydrocarbons contaminated site and refinery effluents.

  3. Anaerobic digestion process

    SciTech Connect

    Ishida, M.; Haga, R.; Odawara, Y.

    1982-10-19

    An algae culture grown on the water from the digested slurry of a biogasification plant serves as a means of removing CO/sub 2/ from the methane stream while purifying the wastewater and providing more biomass for the anaerobic digestion plant. Tested on a sewage-sludge digestion system, the proposed process improved the methane yield by 32% and methane concentration by 53-98 vol % while lowering the concentration of nitrogen and phosphorus in the final water.

  4. Anaerobic Degradation of Cyanuric Acid, Cysteine, and Atrazine by a Facultative Anaerobic Bacterium

    PubMed Central

    Jessee, J. A.; Benoit, R. E.; Hendricks, A. C.; Allen, G. C.; Neal, J. L.

    1983-01-01

    A facultative anaerobic bacterium that rapidly degrades cyanuric acid (CA) was isolated from the sediment of a stream that received industrial wastewater effluent. CA decomposition was measured throughout the growth cycle by using a high-performance liquid chromatography assay, and the concomitant production of ammonia was also measured. The bacterium used CA or cysteine as a major, if not the sole, carbon and energy source under anaerobic, but not aerobic, conditions in a defined medium. The cell yield was greatly enhanced by the simultaneous presence of cysteine and CA in the medium. Cysteine was preferentially used rather than CA early in the growth cycle, but all of the CA was used without an apparent lag after the cysteine was metabolized. Atrazine was also degraded by this bacterium under anaerobic conditions in a defined medium. PMID:16346187

  5. Early anaerobic metabolisms

    PubMed Central

    Canfield, Don E; Rosing, Minik T; Bjerrum, Christian

    2006-01-01

    Before the advent of oxygenic photosynthesis, the biosphere was driven by anaerobic metabolisms. We catalogue and quantify the source strengths of the most probable electron donors and electron acceptors that would have been available to fuel early-Earth ecosystems. The most active ecosystems were probably driven by the cycling of H2 and Fe2+ through primary production conducted by anoxygenic phototrophs. Interesting and dynamic ecosystems would have also been driven by the microbial cycling of sulphur and nitrogen species, but their activity levels were probably not so great. Despite the diversity of potential early ecosystems, rates of primary production in the early-Earth anaerobic biosphere were probably well below those rates observed in the marine environment. We shift our attention to the Earth environment at 3.8 Gyr ago, where the earliest marine sediments are preserved. We calculate, consistent with the carbon isotope record and other considerations of the carbon cycle, that marine rates of primary production at this time were probably an order of magnitude (or more) less than today. We conclude that the flux of reduced species to the Earth surface at this time may have been sufficient to drive anaerobic ecosystems of sufficient activity to be consistent with the carbon isotope record. Conversely, an ecosystem based on oxygenic photosynthesis was also possible with complete removal of the oxygen by reaction with reduced species from the mantle. PMID:17008221

  6. Simple Method for Culturing Anaerobes

    PubMed Central

    Davis, C. E.; Hunter, W. J.; Ryan, J. L.; Braude, A. I.

    1973-01-01

    A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO2. Gentamicin sulfate (50 μg/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use. Images PMID:4571657

  7. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    NASA Astrophysics Data System (ADS)

    Hassan, Siti Roshayu; Dahlan, Irvan

    2013-09-01

    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  8. Economic viability of anaerobic digestion

    SciTech Connect

    Wellinger, A.

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  9. FCPP application to utilize anaerobic digester gas

    SciTech Connect

    Nakayama, Yoshio; Kusama, Nobuyuki; Wada, Katsuya

    1996-12-31

    Toshiba and a municipal organization of Yokohama city are jointly conducting a program to utilize ADG (Anaerobic Digester Gas) more effectively. ADG which contains about 60% methane is produced by anaerobic digestion of waste water treatment sludge and has been used as an energy source for heating digestion tanks in sewage treatment plants and/or for combustion engine fuel. This program is focused on operating a commercial Phosphoric Acid Fuel Cell (PAFC) power plant on ADG because of its inherently high fuel efficiency and low emissions characteristics. According to the following joint program, we have successfully demonstrated an ADG fueled FCPP The success of this study promises that the ADG fueled FCPP, an environment-friendly power generation system, will be added to the line-up of PC25{trademark}C applications.

  10. Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools.

    PubMed

    Mamo, Gashaw

    Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these

  11. The global anaerobic regulator Anr, is involved in cell attachment and aggregation influencing the first stages of biofilm development in Pseudomonas extremaustralis.

    PubMed

    Tribelli, Paula M; Hay, Anthony G; López, Nancy I

    2013-01-01

    Pseudomonas extremaustralis is a versatile Antarctic bacterium, able to grow under microaerobic and anaerobic conditions and is related to several non-pathogenic Pseudomonads. Here we report on the role of the global anaerobic regulator Anr, in the early steps of P. extremaustralis biofilm development. We found that the anr mutant was reduced in its ability to attach, to form aggregates and to display twitching motility but presented higher swimming motility than the wild type. In addition, microscopy revealed that the wild type biofilm contained more biomass and was thicker, but were less rough than that of the anr mutant. In silico analysis of the P. extremaustralis genome for Anr-like binding sites led to the identification of two biofilm-related genes as potential targets of this regulator. When measured using Quantitative Real Time PCR, we found that the anr mutant expressed lower levels of pilG, which encodes a component of Type IV pili and has been previously implicated in cellular adhesion. Levels of morA, involved in signal transduction and flagella development, were also lower in the mutant. Our data suggest that under low oxygen conditions, such as those encountered in biofilms, Anr differentially regulates aggregation and motility thus affecting the first stages of biofilm formation.

  12. The Global Anaerobic Regulator Anr, Is Involved in Cell Attachment and Aggregation Influencing the First Stages of Biofilm Development in Pseudomonas extremaustralis

    PubMed Central

    Tribelli, Paula M.; Hay, Anthony G.; López, Nancy I.

    2013-01-01

    Pseudomonas extremaustralis is a versatile Antarctic bacterium, able to grow under microaerobic and anaerobic conditions and is related to several non-pathogenic Pseudomonads. Here we report on the role of the global anaerobic regulator Anr, in the early steps of P. extremaustralis biofilm development. We found that the anr mutant was reduced in its ability to attach, to form aggregates and to display twitching motility but presented higher swimming motility than the wild type. In addition, microscopy revealed that the wild type biofilm contained more biomass and was thicker, but were less rough than that of the anr mutant. In silico analysis of the P. extremaustralis genome for Anr-like binding sites led to the identification of two biofilm-related genes as potential targets of this regulator. When measured using Quantitative Real Time PCR, we found that the anr mutant expressed lower levels of pilG, which encodes a component of Type IV pili and has been previously implicated in cellular adhesion. Levels of morA, involved in signal transduction and flagella development, were also lower in the mutant. Our data suggest that under low oxygen conditions, such as those encountered in biofilms, Anr differentially regulates aggregation and motility thus affecting the first stages of biofilm formation. PMID:24146909

  13. Characterizing the Anaerobic Response of Chlamydomonas reinhardtii by Quantitative Proteomics

    PubMed Central

    Terashima, Mia; Specht, Michael; Naumann, Bianca; Hippler, Michael

    2010-01-01

    The versatile metabolism of the green alga Chlamydomonas reinhardtii is reflected in its complex response to anaerobic conditions. The anaerobic response is also remarkable in the context of renewable energy because C. reinhardtii is able to produce hydrogen under anaerobic conditions. To identify proteins involved during anaerobic acclimation as well as to localize proteins and pathways to the powerhouses of the cell, chloroplasts and mitochondria from C. reinhardtii in aerobic and anaerobic (induced by 8 h of argon bubbling) conditions were isolated and analyzed using comparative proteomics. A total of 2315 proteins were identified. Further analysis based on spectral counting clearly localized 606 of these proteins to the chloroplast, including many proteins of the fermentative metabolism. Comparative quantitative analyses were performed with the chloroplast-localized proteins using stable isotopic labeling of amino acids ([13C6]arginine/[12C6]arginine in an arginine auxotrophic strain). The quantitative data confirmed proteins previously characterized as induced at the transcript level as well as identified several new proteins of unknown function induced under anaerobic conditions. These proteins of unknown function provide new candidates for further investigation, which could bring insights for the engineering of hydrogen-producing alga strains. PMID:20190198

  14. Anaerobic benzene oxidation via phenol in Geobacter metallireducens.

    PubMed

    Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar; Smith, Jessica A; Bain, Timothy S; Lovley, Derek R

    2013-12-01

    Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (<0.5 μM) of phenol accumulated in cultures of Geobacter metallireducens anaerobically oxidizing benzene to carbon dioxide with the reduction of Fe(III). Phenol was not detected in cell-free controls or in Fe(II)- and benzene-containing cultures of Geobacter sulfurreducens, a Geobacter species that cannot metabolize benzene. The phenol produced in G. metallireducens cultures was labeled with (18)O during growth in H2(18)O, as expected for anaerobic conversion of benzene to phenol. Analysis of whole-genome gene expression patterns indicated that genes for phenol metabolism were upregulated during growth on benzene but that genes for benzoate or toluene metabolism were not, further suggesting that phenol was an intermediate in benzene metabolism. Deletion of the genes for PpsA or PpcB, subunits of two enzymes specifically required for the metabolism of phenol, removed the capacity for benzene metabolism. These results demonstrate that benzene hydroxylation to phenol is an alternative to carboxylation for anaerobic benzene activation and suggest that this may be an important metabolic route for benzene removal in petroleum-contaminated groundwaters, in which Geobacter species are considered to play an important role in anaerobic benzene degradation.

  15. Anaerobically expressed Escherichia coli genes identified by operon fusion techniques.

    PubMed Central

    Choe, M; Reznikoff, W S

    1991-01-01

    Genes that are expressed under anaerobic conditions were identified by operon fusion techniques with a hybrid bacteriophage of lambda and Mu, lambda placMu53, which creates transcriptional fusions to lacZY. Cells were screened for anaerobic expression on XG medium. Nine strains were selected, and the insertion point of the hybrid phage in each strain was mapped on the Escherichia coli chromosome linkage map. The anaerobic and aerobic expression levels of these genes were measured by beta-galactosidase assays in different medium conditions and in the presence of three regulatory mutations (fnr, narL, and rpoN). The anaerobically expressed genes (aeg) located at minute 99 (aeg-99) and 75 (aeg-75) appeared to be partially regulated by fnr, and aeg-93 is tightly regulated by fnr. aeg-60 requires a functional rpoN gene for its anaerobic expression. aeg-46.5 is repressed by narL. aeg-65A and aeg-65C are partially controlled by fnr but only in media containing nitrate or fumarate. aeg-47.5 and aeg-48.5 were found to be anaerobically induced only in rich media. The effects of a narL mutation on aeg-46.5 expression were observed in all medium conditions regardless of the presence or absence of nitrate. This suggests that narL has a regulatory function in the absence of exogenously added nitrate. PMID:1917846

  16. PCB breakdown by anaerobic microorganisms

    SciTech Connect

    Not Available

    1989-03-01

    Recently, altered PCB cogener distribution patterns observed in anaerobic sediment samples from the upper Hudson River are being attributed to biologically mediated reductive dechlorination. The authors report their successful demonstration of biologically mediated reductive dechlorination of an Aroclor mixture. In their investigation, they assessed the ability of microorganisms from PCB-contaminated Hudson River sediments (60-562 ppm PCBs) to dechlorinate Aroclor 1242 under anaerobic conditions by eluting microorganisms from the PCB- contaminated sediments and transferring them to a slurry of reduced anaerobic mineral medium and PCB-free sediments in tightly stoppered bottles. They observed dechlorination to be the most rapid at the highest PCB concentration tried by them.

  17. Alternating Current Influences Anaerobic Electroactive Biofilm Activity.

    PubMed

    Wang, Xin; Zhou, Lean; Lu, Lu; Lobo, Fernanda Leite; Li, Nan; Wang, Heming; Park, Jaedo; Ren, Zhiyong Jason

    2016-09-06

    Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network. Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology.

  18. Anaerobic O-demethylation of phenylmethylethers

    SciTech Connect

    Frazer, A.C.; Young, L.Y.

    1990-01-01

    Anaerobic O-demethylation (AOD) of phenylmethylethers is a process of both basic and applied significance. The aryl-O-methyl ethers are abundant in natural products, particularly as components of lignin. They are present as methoxylated lignin monomers in anaerobic environments and can be completely degraded there by mixed microbial populations. AOD is an essential early step in this process, and it is also a key reaction in the utilization of the O-methyl substituent as a C-one substrate by acetogens. An understanding of the AOD reaction mechanism might suggest new ways in which chemicals could be derived from lignocellulosic materials. The biochemical mechanism for the anaerobic cleavage of the aryl-O-methyl ether bond is an intriguing, but relatively unexplored process. In contrast to aerobic O-demethylating enzymes, AOD appears to involve methyl group transfer. Thus, novel biochemical information on an important biotransformation reaction will be gained from the research proposed. Recently, we have shown that AOD activity is inducible and have developed an assay for detecting AOD activity in cell-free extracts of Acetobacterium woodii. AOD activity is stimulated in vitro by the addition of ATP (1mM) and pyruvate (30 mM), the K{sub M} for vanillate being 0.4 mM. In collaboration with protein purification experts, we proposed to purify the AOD enzyme and characterize the protein(s) and the enzymatic reaction involved. 8 figs., 5 tabs.

  19. Energy positive domestic wastewater treatment: the roles of anaerobic and phototrophic technologies.

    PubMed

    Shoener, B D; Bradley, I M; Cusick, R D; Guest, J S

    2014-05-01

    The negative energy balance of wastewater treatment could be reversed if anaerobic technologies were implemented for organic carbon oxidation and phototrophic technologies were utilized for nutrient recovery. To characterize the potential for energy positive wastewater treatment by anaerobic and phototrophic biotechnologies we performed a comprehensive literature review and analysis, focusing on energy production (as kJ per capita per day and as kJ m(-3) of wastewater treated), energy consumption, and treatment efficacy. Anaerobic technologies included in this review were the anaerobic baffled reactor (ABR), anaerobic membrane bioreactor (AnMBR), anaerobic fluidized bed reactor (AFB), upflow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), microbial electrolysis cell (MEC), and microbial fuel cell (MFC). Phototrophic technologies included were the high rate algal pond (HRAP), photobioreactor (PBR), stirred tank reactor, waste stabilization pond (WSP), and algal turf scrubber (ATS). Average energy recovery efficiencies for anaerobic technologies ranged from 1.6% (MFC) to 47.5% (ABR). When including typical percent chemical oxygen demand (COD) removals by each technology, this range would equate to roughly 40-1200 kJ per capita per day or 110-3300 kJ m(-3) of treated wastewater. The average bioenergy feedstock production by phototrophic technologies ranged from 1200-4700 kJ per capita per day or 3400-13 000 kJ m(-3) (exceeding anaerobic technologies and, at times, the energetic content of the influent organic carbon), with usable energy production dependent upon downstream conversion to fuels. Energy consumption analysis showed that energy positive anaerobic wastewater treatment by emerging technologies would require significant reductions of parasitic losses from mechanical mixing and gas sparging. Technology targets and critical barriers for energy-producing technologies are identified, and the role of integrated anaerobic and

  20. Towards a hybrid anaerobic digester-microbial fuel cell integrated energy recovery system: an overview of the development of an electrogenic biofilm.

    PubMed

    Higgins, Scott R; Lopez, Ryan J; Pagaling, Eulyn; Yan, Tao; Cooney, Michael J

    2013-05-10

    An electrogenic biofilm was developed on a macroporous chitosan-carbon nanotube (CHIT-CNT) electrode under constant poised potential (-0.25V versus Ag/AgCl reference electrode) and flow through conditions utilizing the effluent of an anaerobic digester as both the inoculant and substrate for the electrogenic biofilm. After 125 days of inoculation the bioelectrode demonstrated an open circuit potential of -0.62V and a current density of 9.43μAcm(-3) (at -0.25V). Scanning electron microscopy images indicate thorough surface coverage of the biofilm with a high density of bacterial nanowires physically connecting bacteria to bacteria and bacteria to carbon nanotube (electrode surface) suggesting the nanowires are electrically conductive. DGGE was used to identify the major bacterial and archaeal populations.

  1. TM0486 from the hyperthermophilic anaerobe Thermotoga maritima is a thiamin-binding protein involved in response of the cell to oxidative conditions.

    PubMed

    Dermoun, Zorah; Foulon, Amélie; Miller, Mitchell D; Harrington, Daniel J; Deacon, Ashley M; Sebban-Kreuzer, Corinne; Roche, Philippe; Lafitte, Daniel; Bornet, Olivier; Wilson, Ian A; Dolla, Alain

    2010-07-16

    The COG database was used for a comparative genome analysis with genomes from anaerobic and aerobic microorganisms with the aim of identifying proteins specific to the anaerobic way of life. A total of 33 COGs were identified, five of which correspond to proteins of unknown function. We focused our study on TM0486 from Thermotoga maritima, which belongs to one of these COGs of unknown function, namely COG0011. The crystal structure of the protein was determined at 2 A resolution. The structure adopts a beta alpha beta beta alpha beta ferredoxin-like fold and assembles as a homotetramer. The structure also revealed the presence of a pocket in each monomer that bound an unidentified ligand. NMR and calorimetry revealed that TM0486 specifically bound thiamin with a K(d) of 1.58 microM, but not hydroxymethyl pyrimidine (HMP), which has been implicated as a potential ligand. We demonstrated that the TM0486 gene belongs to the same multicistronic unit as TM0483, TM0484 and TM0485. Although these three genes have been assigned to the transport of HMP, with TM0484 being the periplasmic thiamin/HMP-binding protein and TM0485 and TM0483 the transmembrane and the ATPase components, respectively, our results led us to conclude that this operon encodes an ABC transporter dedicated to thiamin, with TM0486 transporting charged thiamin in the cytoplasm. Given that this transcriptional unit was up-regulated when T. maritima was exposed to oxidative conditions, we propose that, by chelating cytoplasmic thiamin, TM0486 and, by extension, proteins belonging to COG0011 are involved in the response mechanism to stress that could arise during aerobic conditions.

  2. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  3. Implementing Livestock Anaerobic Digestion Projects

    EPA Pesticide Factsheets

    Page provides information to help make an informed decision about installing an anaerobic digester. Is it a good match for a farm’s organic waste, project financing, development guidelines and permit requirements?

  4. Impaired mitochondrial Ca{sup 2+} homeostasis in respiratory chain-deficient cells but efficient compensation of energetic disadvantage by enhanced anaerobic glycolysis due to low ATP steady state levels

    SciTech Connect

    Kleist-Retzow, Juergen-Christoph von ||. E-mail: juergen-christoph.vonkleist@uk-koeln.de; Hue-Tran Hornig-Do; Schauen, Matthias; Eckertz, Sabrina; Tuan Anh Duong Dinh; Stassen, Frank; Lottmann, Nadine; Bust, Maria; Galunska, Bistra; Wielckens, Klaus; Hein, Wolfgang; Beuth, Joseph; Braun, Jan-Matthias; Fischer, Juergen H.; Ganitkevich, Vladimir Y. |; Maniura-Weber, Katharina; Wiesner, Rudolf J. |

    2007-08-15

    Energy-producing pathways, adenine nucleotide levels, oxidative stress response and Ca{sup 2+} homeostasis were investigated in cybrid cells incorporating two pathogenic mitochondrial DNA point mutations, 3243A > G and 3302A > G in tRNA{sup Leu(UUR)}, as well as Rho{sup 0} cells and compared to their parental 143B osteosarcoma cell line. All cells suffering from a severe respiratory chain deficiency were able to proliferate as fast as controls. The major defect in oxidative phosphorylation was efficiently compensated by a rise in anaerobic glycolysis, so that the total ATP production rate was preserved. This enhancement of glycolysis was enabled by a considerable decrease of cellular total adenine nucleotide pools and a concomitant shift in the AMP + ADP/ATP ratios, while the energy charge potential was still in the normal range. Further important consequences were an increased production of superoxide which, however, was neither escorted by major changes in the antioxidative defence systems nor was it leading to substantial oxidative damage. Most interestingly, the lowered mitochondrial membrane potential led to a disturbed intramitochondrial calcium homeostasis, which most likely is a major pathomechanism in mitochondrial diseases.

  5. Bacterial Drug Tolerance under Clinical Conditions Is Governed by Anaerobic Adaptation but not Anaerobic Respiration

    PubMed Central

    Hemsley, Claudia M.; Luo, Jamie X.; Andreae, Clio A.; Butler, Clive S.; Soyer, Orkun S.

    2014-01-01

    Noninherited antibiotic resistance is a phenomenon whereby a subpopulation of genetically identical bacteria displays phenotypic tolerance to antibiotics. We show here that compared to Escherichia coli, the clinically relevant genus Burkholderia displays much higher levels of cells that tolerate ceftazidime. By measuring the dynamics of the formation of drug-tolerant cells under conditions that mimic in vivo infections, we show that in Burkholderia bacteria, oxygen levels affect the formation of these cells. The drug-tolerant cells are characterized by an anaerobic metabolic signature and can be eliminated by oxygenating the system or adding nitrate. The transcriptome profile suggests that these cells are not dormant persister cells and are likely to be drug tolerant as a consequence of the upregulation of anaerobic nitrate respiration, efflux pumps, β-lactamases, and stress response proteins. These findings have important implications for the treatment of chronic bacterial infections and the methodologies and conditions that are used to study drug-tolerant and persister cells in vitro. PMID:25049258

  6. Bacterial drug tolerance under clinical conditions is governed by anaerobic adaptation but not anaerobic respiration.

    PubMed

    Hemsley, Claudia M; Luo, Jamie X; Andreae, Clio A; Butler, Clive S; Soyer, Orkun S; Titball, Richard W

    2014-10-01

    Noninherited antibiotic resistance is a phenomenon whereby a subpopulation of genetically identical bacteria displays phenotypic tolerance to antibiotics. We show here that compared to Escherichia coli, the clinically relevant genus Burkholderia displays much higher levels of cells that tolerate ceftazidime. By measuring the dynamics of the formation of drug-tolerant cells under conditions that mimic in vivo infections, we show that in Burkholderia bacteria, oxygen levels affect the formation of these cells. The drug-tolerant cells are characterized by an anaerobic metabolic signature and can be eliminated by oxygenating the system or adding nitrate. The transcriptome profile suggests that these cells are not dormant persister cells and are likely to be drug tolerant as a consequence of the upregulation of anaerobic nitrate respiration, efflux pumps, β-lactamases, and stress response proteins. These findings have important implications for the treatment of chronic bacterial infections and the methodologies and conditions that are used to study drug-tolerant and persister cells in vitro.

  7. The effect of algae species on the bioelectricity and biodiesel generation through open-air cathode microbial fuel cell with kitchen waste anaerobically digested effluent as substrate.

    PubMed

    Hou, Qingjie; Nie, Changliang; Pei, Haiyan; Hu, Wenrong; Jiang, Liqun; Yang, Zhigang

    2016-10-01

    Five strains algae (Golenkinia sp. SDEC-16, Chlorella vulgaris, Selenastrum capricornutum, Scenedesmus SDEC-8 and Scenedesmus SDEC-13) were screened as an effective way to promote recover electricity from MFC for kitchen waste anaerobically digested effluent (KWADE) treatment. The highest OCV, power density, biomass concentration and total lipid content were obtained with Golenkinia sp. SDEC-16 as the co-inoculum, which were 170mV, 6255mWm(-3), 325mgL(-1) and 38%, respectively. Characteristics of the organics in KWADE were analyzed, and the result showed that the hydrophilic and acidic fractions were more readily degraded, compared to the neutral fractions during the operation. Maximum COD and TN removal efficiency were 43.59% and 37.39% when inoculated with Golenkinia sp. SDEC-16, which were roughly 3.22 and 3.04 times higher than that of S. capricornutum. This study demonstrated that Golenkinia sp. SDEC-16 was a promising species for bioelectricity generation, lipid production and KWADE treatment.

  8. Apparent posttranscriptional block to anaerobic induction of endogenous leukemia virus.

    PubMed Central

    Whitaker-Dowling, P A; Marotti, K R; Anderson, G R

    1979-01-01

    Uninfected Fischer rat cells were induced by anaerobic stress to transcribe high levels of endogenous type C leukemia virus RNA. Complete 35S virus RNA with attached polyadenylic acid sequences was found associated with polysomes, indicating functional mRNA. Since no mature virus was released under these conditions, the presence of a posttranscriptional block to complete virus synthesis is strongly indicated. PMID:232174

  9. Improved anaerobic use of arginine by Saccharomyces cerevisiae.

    PubMed

    Martin, Olga; Brandriss, Marjorie C; Schneider, Gisbert; Bakalinsky, Alan T

    2003-03-01

    Anaerobic arginine catabolism in Saccharomyces cerevisiae was genetically modified to allow assimilation of all four rather than just three of the nitrogen atoms in arginine. This was accomplished by bypassing normal formation of proline, an unusable nitrogen source in the absence of oxygen, and causing formation of glutamate instead. A pro3 ure2 strain expressing a PGK1 promoter-driven PUT2 allele encoding Delta(1)-pyrroline-5-carboxylate dehydrogenase lacking a mitochondrial targeting sequence produced significant cytoplasmic activity, accumulated twice as much intracellular glutamate, and produced twice as much cell mass as the parent when grown anaerobically on limiting arginine as sole nitrogen source.

  10. Anaerobic benzene degradation by bacteria

    PubMed Central

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the ‘key players’ of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. PMID:21450012

  11. Anaerobic Fungi and Their Potential for Biogas Production.

    PubMed

    Dollhofer, Veronika; Podmirseg, Sabine Marie; Callaghan, Tony Martin; Griffith, Gareth Wyn; Fliegerová, Kateřina

    2015-01-01

    Plant biomass is the largest reservoir of environmentally friendly renewable energy on earth. However, the complex and recalcitrant structure of these lignocellulose-rich substrates is a severe limitation for biogas production. Microbial pro-ventricular anaerobic digestion of ruminants can serve as a model for improvement of converting lignocellulosic biomass into energy. Anaerobic fungi are key players in the digestive system of various animals, they produce a plethora of plant carbohydrate hydrolysing enzymes. Combined with the invasive growth of their rhizoid system their contribution to cell wall polysaccharide decomposition may greatly exceed that of bacteria. The cellulolytic arsenal of anaerobic fungi consists of both secreted enzymes, as well as extracellular multi-enzyme complexes called cellulosomes. These complexes are extremely active, can degrade both amorphous and crystalline cellulose and are probably the main reason of cellulolytic efficiency of anaerobic fungi. The synergistic use of mechanical and enzymatic degradation makes anaerobic fungi promising candidates to improve biogas production from recalcitrant biomass. This chapter presents an overview about their biology and their potential for implementation in the biogas process.

  12. Anaerobic Metabolism in Haloferax Genus: Denitrification as Case of Study.

    PubMed

    Torregrosa-Crespo, J; Martínez-Espinosa, R M; Esclapez, J; Bautista, V; Pire, C; Camacho, M; Richardson, D J; Bonete, M J

    2016-01-01

    A number of species of Haloferax genus (halophilic archaea) are able to grow microaerobically or even anaerobically using different alternative electron acceptors such as fumarate, nitrate, chlorate, dimethyl sulphoxide, sulphide and/or trimethylamine. This metabolic capability is also shown by other species of the Halobacteriaceae and Haloferacaceae families (Archaea domain) and it has been mainly tested by physiological studies where cell growth is observed under anaerobic conditions in the presence of the mentioned compounds. This work summarises the main reported features on anaerobic metabolism in the Haloferax, one of the better described haloarchaeal genus with significant potential uses in biotechnology and bioremediation. Special attention has been paid to denitrification, also called nitrate respiration. This pathway has been studied so far from Haloferax mediterranei and Haloferax denitrificans mainly from biochemical point of view (purification and characterisation of the enzymes catalysing the two first reactions). However, gene expression and gene regulation is far from known at the time of writing this chapter.

  13. Acetate Metabolism in Anaerobes from the Domain Archaea

    PubMed Central

    Ferry, James G.

    2015-01-01

    Acetate and acetyl-CoA play fundamental roles in all of biology, including anaerobic prokaryotes from the domains Bacteria and Archaea, which compose an estimated quarter of all living protoplasm in Earth’s biosphere. Anaerobes from the domain Archaea contribute to the global carbon cycle by metabolizing acetate as a growth substrate or product. They are components of anaerobic microbial food chains converting complex organic matter to methane, and many fix CO2 into cell material via synthesis of acetyl-CoA. They are found in a diversity of ecological habitats ranging from the digestive tracts of insects to deep-sea hydrothermal vents, and synthesize a plethora of novel enzymes with biotechnological potential. Ecological investigations suggest that still more acetate-metabolizing species with novel properties await discovery. PMID:26068860

  14. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  15. Arsenic, Anaerobes, and Astrobiology

    NASA Astrophysics Data System (ADS)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  16. Factors involved in anaerobic growth of Saccharomyces cerevisiae.

    PubMed

    Ishtar Snoek, I S; Yde Steensma, H

    2007-01-01

    Life in the absence of molecular oxygen requires several adaptations. Traditionally, the switch from respiratory metabolism to fermentation has attracted much attention in Saccharomyces cerevisiae, as this is the basis for the use of this yeast in the production of alcohol and in baking. It has also been clear that under anaerobic conditions the yeast is not able to synthesize sterols and unsaturated fatty acids and that for anaerobic growth these have to be added to the media. More recently it has been found that many more factors play a role. Several other biosynthetic reactions also require molecular oxygen and the yeast must have alternatives for these. In addition, the composition of the cell wall and cell membrane show major differences when aerobic and anaerobic cells are compared. All these changes are reflected by the observation that the transcription of more than 500 genes changes significantly between aerobically and anaerobically growing cultures. In this review we will give an overview of the factors that play a role in the survival in the absence of molecular oxygen.

  17. How anaerobic is the Wingate Anaerobic Test for humans?

    PubMed

    Beneke, R; Pollmann, C; Bleif, I; Leithäuser, R M; Hütler, M

    2002-08-01

    The Wingate Anaerobic Test (WAnT) is generally used to evaluate anaerobic cycling performance, but knowledge of the metabolic profile of WAnT is limited. Therefore the energetics of WAnT was analysed with respect to working efficiency and performance. A group of 11 male subjects [mean (SD), age 21.6 (3.8) years, height 178.6 (6.6) cm, body mass 82.2 (12.1) kg] performed a maximal incremental exercise test and a WAnT. Lactic and alactic anaerobic energy outputs were calculated from net lactate production and the fast component of the kinetics of post-exercise oxygen uptake. Aerobic metabolism was determined from oxygen uptake during exercise. The WAnT mean power of 683 (96.0) W resulted from a total energy output above the value at rest of 128.1 (23.2) kJ x 30 s(-1) [mean metabolic power=4.3 (0.8) kW] corresponding to a working efficiency of 16.2 (1.6)%. The WAnT working efficiency was lower (P < 0.01) than the corresponding value of 24.1 (1.7)% at 362 (41) W at the end of an incremental exercise test. During WAnT the fractions of the energy from aerobic, anaerobic alactic and lactic acid metabolism were 18.6 (2.5)%, 31.1 (4.6)%, and 50.3 (5.1)%, respectively. Energy from metabolism of anaerobic lactic acid explained 83% and 81% of the variance of WAnT peak and mean power, respectively. The results indicate firstly that WAnT requires the use of more anaerobically derived energy than previously estimated, secondly that anaerobic metabolism is dominated by glycolysis, thirdly that WAnT mechanical efficiency is lower than that found in aerobic exercise tests, and fourthly that the latter finding partly explains discrepancies between previously published and the present data about the metabolic profile of WAnT.

  18. Response of anaerobic granular sludge to single-wall carbon nanotube exposure.

    PubMed

    Li, Ling-Li; Tong, Zhong-Hua; Fang, Cai-Yun; Chu, Jian; Yu, Han-Qing

    2015-03-01

    Rapid development and application of nanotechnology have introduced various nanopaticles, such as single-walled carbon nanotubes (SWCNTs), whose negative effects on aquatic organisms and cultured cells have been reported, into anaerobic wastewater treatment systems. In this study, the response of methanogenic sludge exposed to SWCNTs in anaerobic digestion process was investigated. Results show that SWCNTs, at a concentration up to 1000 mg/L, had no significant impact on the maximum methane yield. In contrast, they induced much faster substrate utilization and methane production rates. Scanning electron microscopy examination shows that more extracellular polymeric substances (EPS) were excreted from the anaerobic sludge and closely interacted with SWCNTs. Such an interaction prevented nanoparticles from piercing into cells, and thus reduced their cytotoxicity. In the compact anaerobic granule structure, SWCNTs exposure enhanced the electrical conductance of the sludge, which might promote direct interspecies electron transfer among anaerobic fermentative bacteria and methanogens in the anaerobic digestion process. Our results provide useful information to understand the response of anaerobic microorganisms to CNTs in complex environmental matrix.

  19. Processing anaerobic sludge for extended storage as anaerobic digester inoculum.

    PubMed

    Li, Jiajia; Zicari, Steven M; Cui, Zongjun; Zhang, Ruihong

    2014-08-01

    Thermophilic anaerobic sludge was processed to reduce the volume and moisture content in order to reduce costs for storing and transporting the sludge as microbial inoculum for anaerobic digester startup. The moisture content of the sludge was reduced from 98.7% to 82.0% via centrifugation and further to 71.5% via vacuum evaporation. The processed sludge was stored for 2 and 4 months and compared with the fresh sludge for the biogas and methane production using food waste and non-fat dry milk as substrates. It was found that fresh unprocessed sludge had the highest methane yield and the yields of both unprocessed and processed sludges decreased during storage by 1-34%, however processed sludges seemed to regain some activity after 4 months of storage as compared to samples stored for only 2 months. Maximum methane production rates obtained from modified Gompertz model application also increased between the 2-month and 4-month processed samples.

  20. Benzylsuccinate Formation as a Means of Anaerobic Toluene Activation by Sulfate-Reducing Strain PRTOL1

    PubMed Central

    Beller, H. R.; Spormann, A. M.

    1997-01-01

    Permeabilized cells of toluene-mineralizing, sulfate-reducing strain PRTOL1 catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. Recent in vitro studies with two toluene-mineralizing, denitrifying bacteria demonstrated the same fumarate addition reaction and indicated that it may be the first step of anaerobic toluene degradation. This study with strain PRTOL1 shows that anaerobic toluene activation by fumarate addition occurs in bacteria as disparate as sulfate-reducing and denitrifying species (members of the delta and beta subclasses of the Proteobacteria, respectively). PMID:16535701

  1. Enzyme Systems of Anaerobes for Biomass Conversion.

    PubMed

    Munir, Riffat; Levin, David B

    Biofuels from abundantly available cellulosic biomass are an attractive alternative to current petroleum-based fuels (fossil fuels). Although several strategies exist for commercial production of biofuels, conversion of biomass to biofuels via consolidated bioprocessing offers the potential to reduce production costs and increase processing efficiencies. In consolidated bioprocessing (CBP), enzyme production, cellulose hydrolysis, and fermentation are all carried out in a single-step by microorganisms that efficiently employ a multitude of intricate enzymes which act synergistically to breakdown cellulose and its associated cell wall components. Various strategies employed by anaerobic cellulolytic bacteria for biomass hydrolysis are described in this chapter. In addition, the regulation of CAZymes, the role of "omics" technologies in assessing lignocellulolytic ability, and current strategies for improving biomass hydrolysis for optimum biofuel production are highlighted.

  2. Assessment of hydrogen metabolism in commercial anaerobic digesters.

    PubMed

    Kern, Tobias; Theiss, Juliane; Röske, Kerstin; Rother, Michael

    2016-05-01

    Degradation of biomass in the absence of exogenous electron acceptors via anaerobic digestion involves a syntrophic association of a plethora of anaerobic microorganisms. The commercial application of this process is the large-scale production of biogas from renewable feedstock as an alternative to fossil fuels. After hydrolysis of polymers, monomers are fermented to short-chain fatty acids and alcohols, which are further oxidized to acetate. Carbon dioxide, molecular hydrogen (H2), and acetate generated during the process are converted to methane by methanogenic archaea. Since many of the metabolic pathways as well as the syntrophic interactions and dependencies during anaerobic digestion involve formation, utilization, or transfer of H2, its metabolism and the methanogenic population were assessed in various samples from three commercial biogas plants. Addition of H2 significantly increased the rate of methane formation, which suggested that hydrogenotrophic methanogenesis is not a rate-limiting step during biogas formation. Methanoculleus and Methanosarcina appeared to numerically dominate the archaeal population of the three digesters, but their proportion and the Bacteria-to-Archaea ratio did not correlate with the methane productivity. Instead, hydrogenase activity in cell-free extracts from digester sludge correlated with methane productivity in a positive fashion. Since most microorganisms involved in biogas formation contain this activity, it approximates the overall anaerobic metabolic activity and may, thus, be suitable for monitoring biogas reactor performance.

  3. Anaerobic glycerol production by Saccharomyces cerevisiae strains under hyperosmotic stress.

    PubMed

    Modig, Tobias; Granath, Katarina; Adler, Lennart; Lidén, Gunnar

    2007-05-01

    Glycerol formation is vital for reoxidation of nicotinamide adenine dinucleotide (reduced form; NADH) under anaerobic conditions and for the hyperosmotic stress response in the yeast Saccharomyces cerevisiae. However, relatively few studies have been made on hyperosmotic stress under anaerobic conditions. To study the combined effect of salt stress and anaerobic conditions, industrial and laboratory strains of S. cerevisiae were grown anaerobically on glucose in batch-cultures containing 40 g/l NaCl. The time needed for complete glucose conversion increased considerably, and the specific growth rates decreased by 80-90% when the cells were subjected to the hyperosmotic conditions. This was accompanied by an increased yield of glycerol and other by-products and reduced biomass yield in all strains. The slowest fermenting strain doubled its glycerol yield (from 0.072 to 0.148 g/g glucose) and a nearly fivefold increase in acetate formation was seen. In more tolerant strains, a lower increase was seen in the glycerol and in the acetate, succinate and pyruvate yields. Additionally, the NADH-producing pathway from acetaldehyde to acetate was analysed by overexpressing the stress-induced gene ALD3. However, this had no or very marginal effect on the acetate and glycerol yields. In the control experiments, the production of NADH from known sources well matched the glycerol formation. This was not the case for the salt stress experiments in which the production of NADH from known sources was insufficient to explain the formed glycerol.

  4. A Radiochemical Biotechnological Approach: Preliminary Study of Lactose Uptake Rate by Kefir Cells, Using {sup 14}C-labeled Lactose, in Anaerobic Fermentation

    SciTech Connect

    Golfinopoulos, A.; Soupioni, M.; Kanellaki, M.; Koutinas, A. A.

    2008-08-14

    The effect of initial lactose concentration on lactose uptake rate by kefir free cells, during the lactose fermentation, was studied in this work. For the investigation {sup 14}C-labelled lactose was used due to the fact that labeled and unlabeled molecules are fermented in the same way. The results illustrated lactose uptake rates are about up to two fold higher at lower initial (convolution sign)Be densities as compared with higher initial (convolution sign)Be densities.

  5. Anaerobic digestion of aliphatic polyesters.

    PubMed

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry.

  6. Naphthalecin, a novel antibiotic produced by the anaerobic bacterium, Sporotalea colonica sp. nov.

    PubMed

    Ezaki, Masami; Muramatsu, Hideyuki; Takase, Shigehiro; Hashimoto, Michizane; Nagai, Koji

    2008-04-01

    A novel antibiotic naphthalecin was purified and isolated from the cells of an anaerobic bacterium isolated from a soil sample. This antibiotic contained a naphthalene moiety, so named as naphthalecin, and showed antibacterial activity against gram positive species. The producing strain, an obligate anaerobe, was identified as a new species of the genus Sporotalea. Identification of the bacterium, cultivation, purification, structure determination, and antibacterial activity are shown.

  7. Anaerobic treatment performance and microbial population of thermophilic upflow anaerobic filter reactor treating awamori distillery wastewater.

    PubMed

    Tang, Yue-Qin; Fujimura, Yutaka; Shigematsu, Toru; Morimura, Shigeru; Kida, Kenji

    2007-10-01

    Distillery wastewater from awamori making was anaerobically treated for one year using thermophilic upflow anaerobic filter (UAF) reactors packed with pyridinium group-containing nonwoven fabric material. The microbial structure and spatial distribution of microorganisms on the support material were characterized using molecular biological methods. The reactor steadily achieved a high TOC loading rate of 18 g/l/d with approximately 80% TOC removal efficiency when non-diluted wastewater was fed. The maximum TOC loading rate increased to 36 g/l/d when treating thrice-diluted wastewater. However, the TOC removal efficiency and gas evolution rate decreased compared with that when non-diluted wastewater was used. Methanogens closely related to Methanosarcina thermophila and Methanoculleus bourgensis and bacteria in the phyla Firmicutes and Bacteroidetes were predominant methanogens and bacteria in the thermophilic UFA reactor, as indicated by 16S rRNA gene clone analysis. Fluorescence in situ hybridization (FISH) results showed that a large quantity of bacterial cells adhered throughout the whole support, and Methanosarcina-like methanogens existed mainly in the relative outside region while Methanoculleus cells were located in the relative inner part of the support. The support material used proved to be an excellent carrier for microorganisms, and a UAF reactor using this kind of support can be used for high-rate treatment of awamori/shochu distillery wastewater.

  8. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1991-06-01

    This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

  9. Infected Pneumatocele Following Anaerobic Pneumonia in Adult

    PubMed Central

    Chung, Yeon Tae; Lee, Kyung Duk; Seon, Kyoung Youn; Lee, Jong Hyun; Lee, Sung Ho; Choi, Se Ho

    2005-01-01

    We report a case of an infected pneumatocele in the course of anaerobic pneumonia in an adult. To the best of our knowledge, anaerobic pneumonia complicated by a pneumatocele in an adult has not previously been described. The pneumatocele occurred on the fifth day of hospitalization, and rapidly increased in size, with the development of a subsequent mixed anaerobe infection. A pig-tail catheter was inserted and the pus drained. The bacterial culture from the pus was positive for three anaerobes: Bacteroid species, Peptostreptococcus asaccharolyticus and Fusobacterium species. Intravenous antibiotics and percutaneous catheter drainage resulted in a successful treatment. PMID:16491835

  10. Bioconversion of selenate in methanogenic anaerobic granular sludge.

    PubMed

    Astratinei, Violeta; van Hullebusch, Eric; Lens, Piet

    2006-01-01

    The capacity of anaerobic granular sludge to remove selenate from contaminated wastewater was investigated. The potential of different types of granular sludge to remove selenate from the liquid phase was compared to that of suspended sludge and contaminated soil and sediment samples. The selenate removal rates ranged from 400 to 1500 microg g VSS(-1) h(-1), depending on the source of biomass, electron donor, and the initial selenate concentration. The granular structure protects the microorganisms when exposed to high selenate concentrations (0.1 to 1 mM). Anaerobic granular sludge "Eerbeek," originating from a UASB reactor treating paper mill wastewater, removed about 90, 50, and 36% of 0.1, 0.5, and 1 mM of Se, respectively, from the liquid phase when incubated with 20 mM lactate at 30 degrees C and pH 7.5. Selenite, elemental Se (Se(o)), and metal selenide precipitates were the conversion products. Enrichments from the anaerobic granular sludge "Eerbeek" were able to convert 90% of the 10-mM selenate to Se(o) at a rate of 1505 microg Se(VI) g cells(-1) h(-1), a specific growth rate of 0.0125 g cells h(-1), and a yield of 0.083 g cells mg Se(-1). Both microbial metabolic processes (e.g dissimilatory reduction) as well as microbially mediated physicochemical mechanisms (adsorption and precipitation) contribute to the removal of selenate from the Se-containing medium.

  11. Metabolic regulation as a consequence of anaerobic 5-methylthioadenosine recycling in Rhodospirillum rubrum

    DOE PAGES

    North, Justin A.; Sriram, Jaya; Chourey, Karuna; ...

    2016-07-12

    Rhodospirillum rubrum possesses a novel oxygen-independent, aerobic methionine salvage pathway (MSP) for recycling methionine from 5-methylthioadenosine (MTA), the MTA-isoprenoid shunt. This organism can also metabolize MTA as a sulfur source under anaerobic conditions, suggesting that the MTA-isoprenoid shunt may also function anaerobically as well. In this study, deep proteomics profiling, directed metabolite analysis, and reverse transcriptase quantitative PCR (RT-qPCR) revealed metabolic changes in response to anaerobic growth on MTA versus sulfate as sole sulfur source. The abundance of protein levels associated with methionine transport, cell motility, and chemotaxis increased in the presence of MTA over that in the presence ofmore » sulfate. Purine salvage from MTA resulted primarily in hypoxanthine accumulation and a decrease in protein levels involved in GMP-to-AMP conversion to balance purine pools. Acyl coenzyme A (acyl-CoA) metabolic protein levels for lipid metabolism were lower in abundance, whereas poly-β-hydroxybutyrate synthesis and storage were increased nearly 10-fold. The known R. rubrum aerobic MSP was also shown to be upregulated, to function anaerobically, and to recycle MTA. This suggested that other organisms with gene homologues for the MTA-isoprenoid shunt may also possess a functioning anaerobic MSP. In support of our previous findings that ribulose-1,5-carboxylase/oxygenase (RubisCO) is required for an apparently purely anaerobic MSP, RubisCO transcript and protein levels both increased in abundance by over 10-fold in cells grown anaerobically on MTA over those in cells grown on sulfate, resulting in increased intracellular RubisCO activity. Lastly, these results reveal for the first time global metabolic responses as a consequence of anaerobic MTA metabolism compared to using sulfate as the sulfur source.« less

  12. Metabolic Regulation as a Consequence of Anaerobic 5-Methylthioadenosine Recycling in Rhodospirillum rubrum

    PubMed Central

    North, Justin A.; Sriram, Jaya; Chourey, Karuna; Ecker, Christopher D.; Sharma, Ritin; Wildenthal, John A.; Hettich, Robert L.

    2016-01-01

    ABSTRACT Rhodospirillum rubrum possesses a novel oxygen-independent, aerobic methionine salvage pathway (MSP) for recycling methionine from 5-methylthioadenosine (MTA), the MTA-isoprenoid shunt. This organism can also metabolize MTA as a sulfur source under anaerobic conditions, suggesting that the MTA-isoprenoid shunt may also function anaerobically as well. In this study, deep proteomics profiling, directed metabolite analysis, and reverse transcriptase quantitative PCR (RT-qPCR) revealed metabolic changes in response to anaerobic growth on MTA versus sulfate as sole sulfur source. The abundance of protein levels associated with methionine transport, cell motility, and chemotaxis increased in the presence of MTA over that in the presence of sulfate. Purine salvage from MTA resulted primarily in hypoxanthine accumulation and a decrease in protein levels involved in GMP-to-AMP conversion to balance purine pools. Acyl coenzyme A (acyl-CoA) metabolic protein levels for lipid metabolism were lower in abundance, whereas poly-β-hydroxybutyrate synthesis and storage were increased nearly 10-fold. The known R. rubrum aerobic MSP was also shown to be upregulated, to function anaerobically, and to recycle MTA. This suggested that other organisms with gene homologues for the MTA-isoprenoid shunt may also possess a functioning anaerobic MSP. In support of our previous findings that ribulose-1,5-carboxylase/oxygenase (RubisCO) is required for an apparently purely anaerobic MSP, RubisCO transcript and protein levels both increased in abundance by over 10-fold in cells grown anaerobically on MTA over those in cells grown on sulfate, resulting in increased intracellular RubisCO activity. These results reveal for the first time global metabolic responses as a consequence of anaerobic MTA metabolism compared to using sulfate as the sulfur source. PMID:27406564

  13. Anaerobic bacteria from hypersaline environments.

    PubMed Central

    Ollivier, B; Caumette, P; Garcia, J L; Mah, R A

    1994-01-01

    Strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. To date, six anaerobic fermentative genera, containing nine species, have been described. Two of them are homoacetogens. Six species belong to the family Haloanaerobiaceae, as indicated by their unique 16S rRNA oligonucleotide sequences. Desulfohalobium retbaense and Desulfovibrio halophilus represent the only two moderately halophilic sulfate reducers so far reported. Among anoxygenic phototrophic anaerobes, a few purple bacteria with optimal growth at salinities between 6 and 11% NaCl have been isolated from hypersaline habitats. They belong to the genera Rhodospirillum, Chromatium, Thiocapsa, and Ectothiorhodospira. The commonest organisms isolated so far are Chromatium salexigens, Thiocapsa halophila, and Rhodospirillum salinarum. Extremely halophilic purple bacteria have most commonly been isolated from alkaline brines and require about 20 to 25% NaCl for optimal growth. They belong to the family Ectothiorodhospiraceae. Their osmoregulation involves synthesis or uptake of compatible solutes such as glycine-betaine that accumulate in their cytoplasm. The existence of methanogens in hypersaline environments is related to the presence of noncompetitive substrates such as methylamines, which originate mainly from the breakdown of osmoregulatory amines. Methanogenesis probably does not contribute to the mineralization of carbohydrates at NaCl concentrations higher than 15%. Above this concentration, sulfate reduction is probably the main way to oxidize H2 (although at rates too low to use up all the H2 formed) and occupies a terminal function kn the degradation of carbohydrates. Three genera and five species of halophilic methylotrophic methanogens have been reported. A bloom of phototrophic bacteria in the marine salterns of Salins-de-Giraud, located on the

  14. Insights into the global regulation of anaerobic metabolism for improved biohydrogen production.

    PubMed

    Lu, Yuan; Zhao, Hongxin; Zhang, Chong; Xing, Xin-Hui

    2016-01-01

    To improve the biohydrogen yield in bacterial dark fermentation, a new approach of global anaerobic regulation was introduced. Two cellular global regulators FNR and NarP were overexpressed in two model organisms: facultatively anaerobic Enterobacter aerogenes (Ea) and strictly anaerobic Clostridium paraputrificum (Cp). The overexpression of FNR and NarP greatly altered anaerobic metabolism and increased the hydrogen yield by 40%. Metabolic analysis showed that the global regulation caused more reducing environment inside the cell. To get a thorough understanding of the global metabolic regulation, more genes (fdhF, fhlA, ppk, Cb-fdh1, and Sc-fdh1) were overexpressed in different Ea and Cp mutants. For the first time, it demonstrated that there were approximately linear relationships between the relative change of hydrogen yield and the relative change of NADH yield or ATP yield. It implied that cellular reducing power and energy level played vital roles in the biohydrogen production.

  15. Analysis of ZVI corrosion products and their functions in the combined ZVI and anaerobic sludge system.

    PubMed

    Zhu, Liang; Gao, Kaituo; Jin, Jie; Lin, Haizhuan; Xu, Xiangyang

    2014-11-01

    The zero-valent iron (ZVI) corrosion products and their functions were investigated in the combined ZVI and anaerobic sludge system. Results showed that ZVI corrosion occurred, and the reductive transformation and dechlorination of p-chloronitrobenzene (p-ClNB) by the anaerobic sludge were enhanced. In the combined systems with different types of ZVIs and mass ratios of anaerobic sludge to ZVI, a considerable amount of suspended iron compounds was produced and coated onto the microbial cells. However, the microbial cellular structure was damaged, and the p-ClNB reductive transformation was affected adversely after the long-term presence of nanoscale ZVI (NZVI) or reduced ZVI (RZVI) with a high concentration of 5 g L(-1). The oxidized products of FeOOH and Fe3O4 were found on the surface of ZVI, which are speculated to act as electron mediators and consequently facilitate the utilization of electron donors by the anaerobic microbes.

  16. Succinate and Lactate Production from Euglena gracilis during Dark, Anaerobic Conditions

    PubMed Central

    Tomita, Yuko; Yoshioka, Kazumasa; Iijima, Hiroko; Nakashima, Ayaka; Iwata, Osamu; Suzuki, Kengo; Hasunuma, Tomohisa; Kondo, Akihiko; Hirai, Masami Yokota; Osanai, Takashi

    2016-01-01

    Euglena gracilis is a eukaryotic, unicellular phytoflagellate that has been widely studied in basic science and applied science. Under dark, anaerobic conditions, the cells of E. gracilis produce a wax ester that can be converted into biofuel. Here, we demonstrate that under dark, anaerobic conditions, E. gracilis excretes organic acids, such as succinate and lactate, which are bulk chemicals used in the production of bioplastics. The levels of succinate were altered by changes in the medium and temperature during dark, anaerobic incubation. Succinate production was enhanced when cells were incubated in CM medium in the presence of NaHCO3. Excretion of lactate was minimal in the absence of external carbon sources, but lactate was produced in the presence of glucose during dark, anaerobic incubation. E. gracilis predominantly produced L-lactate; however, the percentage of D-lactate increased to 28.4% in CM medium at 30°C. Finally, we used a commercial strain of E. gracilis for succinate production and found that nitrogen-starved cells, incubated under dark, anaerobic conditions, produced 869.6 mg/L succinate over a 3-day incubation period, which was 70-fold higher than the amount produced by nitrogen-replete cells. This is the first study to demonstrate organic acid excretion by E. gracilis cells and to reveal novel aspects of primary carbon metabolism in this organism. PMID:28066371

  17. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber....

  18. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber....

  19. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber....

  20. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber....

  1. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber....

  2. Factor Analysis of Various Anaerobic Power Tests.

    ERIC Educational Resources Information Center

    Manning, James M.; And Others

    A study investigated the relationship between selected anthropometric variables and of numerous anaerobic power tests with measures obtained on an isokinetic dynamometer. Thirty-one male college students performed several anaerobic power tests, including: the vertical jump using the Lewis formula; the Margaria-Kalamen stair climb test; the Wingate…

  3. Anaerobic Infections in Children with Neurological Impairments.

    ERIC Educational Resources Information Center

    Brook, Itzhak

    1995-01-01

    Children with neurological impairments are prone to develop serious infection with anaerobic bacteria. The most common anaerobic infections are decubitus ulcers; gastrostomy site wound infections; pulmonary infections (aspiration pneumonia, lung abscesses, and tracheitis); and chronic suppurative otitis media. The unique microbiology of each of…

  4. Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

    SciTech Connect

    Xun, Luying

    2009-11-20

    The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10^(-10) nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA degrading culture under anaerobic conditions, our finding may promote the use of certain metals that forms more stable metal-EDTA complexes than Pu(III)-EDTA to prevent the enhanced mobility. Further, our data explain why EDTA is the most dominant organic pollutant in surface waters, due to the lack of degradation of certain metal-EDTA complexes.

  5. Biodegradability and toxicity assessment of bleach plant effluents treated anaerobically.

    PubMed

    Chaparro, T R; Botta, C M; Pires, E C

    2010-01-01

    As part of an experimental project on the treatment of bleach plant effluents the results of biodegradability and toxicity assessment of effluents from a bench-scale horizontal anaerobic immobilized bioreactor (HAIB) are discussed in this paper. The biodegradability of the bleach plant effluents from a Kraft pulp mill treated in the HAIB was evaluated using the modified Zahn-Wellens test. The inoculum came from a pulp mill wastewater treatment plant and the dissolved organic carbon (DOC) was used as the indicator of organic matter removal. The acute and chronic toxicity removal during the anaerobic treatment was estimated using Daphnia similis and Ceriodaphnia silvestrii respectively. Moreover, the evaluation of chromosome aberrations (CA), micronucleus frequencies (MN) and mitotic index (IM) in Allium cepa cells were used as genotoxicity indicators. The results indicate that the effluents from the anaerobic reactor are amenable to aerobic polishing. Acute and chronic toxicity were reduced by 90 and 81%, respectively. The largest CA and MN incidence in the meristematic cells of A. cepa were observed after exposure to the raw bleach plant effluent. The HAIB was able to reduce the acute and chronic toxicity as well as chromosome aberrations and the occurrence of micronucleus.

  6. Anaerobic Mercury Methylation and Demethylation by Geobacter bemidjiensis Bem

    DOE PAGES

    Lu, Xia; Liu, Yurong; Johs, Alexander; ...

    2016-03-28

    Two competing processes controlling the net production and bioaccumulation of neurotoxic methylmercury (MeHg) in natural ecosystems are microbial methylation and demethylation. Though mercury (Hg) methylation by anaerobic microorganisms and demethylation by aerobic Hg-resistant bacteria have both been extensively studied, little attention has been given to MeHg degradation by anaerobic bacteria, particularly the iron-reducing bacterium Geobacter bemidjensis Bem. Here we report, for the first time, that the strain G. bemidjensis Bem can methylate inorganic Hg and degrade MeHg concurrently under anoxic conditions. Our results suggest that G. bemidjensis cells utilize a reductive demethylation pathway to degrade MeHg, with elemental Hg(0) asmore » the major reaction product, possibly due to the presence of homologs encoding both organo-mercurial lyase (MerB) and mercuric reductase (MerA) in this organism. In addition, the cells can mediate multiple reactions including Hg/MeHg sorption, Hg reduction and oxidation, resulting in both time and concentration dependent Hg species transformations. Moderate concentrations (10 500 M) of Hg-binding ligands such as cysteine enhance Hg(II) methylation but inhibit MeHg degradation. These findings indicate a cycle of methylation and demethylation among anaerobic bacteria and suggest that mer-mediated demethylation may play a role in the net balance of MeHg production in anoxic water and sediments.« less

  7. Anaerobic biorefinery: Current status, challenges, and opportunities.

    PubMed

    Sawatdeenarunat, Chayanon; Nguyen, Duc; Surendra, K C; Shrestha, Shilva; Rajendran, Karthik; Oechsner, Hans; Xie, Li; Khanal, Samir Kumar

    2016-09-01

    Anaerobic digestion (AD) has been in use for many decades. To date, it has been primarily aimed at treating organic wastes, mainly manures and wastewater sludge, and industrial wastewaters. However, with the current advancements, a more open mind is required to look beyond these somewhat restricted original applications of AD. Biorefineries are such concepts, where multiple products including chemicals, fuels, polymers etc. are produced from organic feedstocks. The anaerobic biorefinery concept is now gaining increased attention, utilizing AD as the final disposal step. This review aims at evaluating the potential significance of anaerobic biorefineries, including types of feedstocks, uses for the produced energy, as well as sustainable applications of the generated residual digestate. A comprehensive analysis of various types of anaerobic biorefineries has been developed, including both large-scale and household level applications. Finally, future directives are highlighted showing how anaerobic biorefinery concept could impact the bioeconomy in the near future.

  8. Toxicants inhibiting anaerobic digestion: a review.

    PubMed

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  9. Anaerobic digestion for household organics

    SciTech Connect

    Sinclair, R.; Kelleher, M.

    1995-04-01

    Considerable success in using anaerobic technology for processing household organics is being reported by several recently constructed facilities in Europe. Organic residuals collected separately in a Belgian town are processed to produce biogas and a compost-like material in less than one month. The dry anaerobic conversion process (DRANCO) was developed by Organic Waste Systems (OWS) in the 1980s, with the collaboration of Professor Willy Verstraete at the University of Ghent`s Laboratory of Applied Microbial Ecology. The patented process converts solid and semisolid organic residuals into biogas (for energy recovery) and a stable humus like product. The plant has competing odor sources such as the active landfill and the surrounding farmland - in fact, the smell of livestock manure is quite prevalent in this heavily agricultural area. Addition of the nonrecyclable paper fraction to the feedstock improves the carbon/nitrogen ratio, soaks up moisture, and absorbs odor. The entire Brecht facility does not occupy much space and total material retention time at the site is one month, compared to a number of months for aerobic systems. It also has a low staffing requirement, provides energy self-sufficiency, and the final soil enhancement product meets established quality standards.

  10. Anaerobic digestion in rural China

    SciTech Connect

    Henderson, J.P.

    1997-01-01

    The People`s Republic of China has been promoting underground, individual, anaerobic digesters to process rural organic materials. This strategy has resulted in approximately five million household anaerobic digesters installed in China today. Simple reactors provide energy and fertilizer for Chinese farms and villages. Another benefit includes improved household sanitation. Reactor design has evolved over time. In the standard modern design, effluent is removed from the reactor at the top of the water column, meaning that supernatant is collected rather than sludge. Additionally, no mixing of the system occurs when effluent is removed. In some systems, a vertical cylindrical pull-rod port is added to the base of the effluent port. Effluent is removed by moving the pull-rod - simply a wooden shaft with a metal disk on the bottom - up and down in the port. A bucket can be placed directly under the pull-rod port, simplifying effluent removal, while the movement of the wooden shaft provides some mixing in the reactor. The gas primarily is used for cooking and lighting. A digester can provide approximately 60 percent of a family`s energy needs. Effluent from the reactors is an odorless, dark colored slurry, primarily used as an agricultural fertilizer. 3 figs.

  11. Mechanism of anaerobic degradation of triethanolamine by a homoacetogenic bacterium.

    PubMed

    Speranza, Giovanna; Morelli, Carlo F; Cairoli, Paola; Müller, Britta; Schink, Bernhard

    2006-10-20

    Triethanolamine (TEA) is converted into acetate and ammonia by a strictly anaerobic, gram-positive Acetobacterium strain LuTria3. Fermentation experiments with resting cell suspensions and specifically deuterated substrates indicate that in the acetate molecule the carboxylate and the methyl groups correspond to the alcoholic function and to its adjacent methylene group, respectively, of the 2-hydroxyethyl unit of TEA. A 1,2 shift of a hydrogen (deuterium) atom from -CH2-O- to =N-CH2- without exchange with the medium was observed. This fact gives evidence that a radical mechanism occurs involving the enzyme and/or coenzyme molecule as a hydrogen carrier. Such a biodegradation appears analogous to the conversion of 2-phenoxyethanol into acetate mediated by another strain of the anaerobic homoacetogenic bacterium Acetobacterium.

  12. Mechanism of anaerobic degradation of triethanolamine by a homoacetogenic bacterium

    SciTech Connect

    Speranza, Giovanna . E-mail: giovanna.speranza@unimi.it; Morelli, Carlo F.; Cairoli, Paola; Mueller, Britta; Schink, Bernhard

    2006-10-20

    Triethanolamine (TEA) is converted into acetate and ammonia by a strictly anaerobic, gram-positive Acetobacterium strain LuTria3. Fermentation experiments with resting cell suspensions and specifically deuterated substrates indicate that in the acetate molecule the carboxylate and the methyl groups correspond to the alcoholic function and to its adjacent methylene group, respectively, of the 2-hydroxyethyl unit of TEA. A 1,2 shift of a hydrogen (deuterium) atom from -CH{sub 2} -O- to =N-CH{sub 2} - without exchange with the medium was observed. This fact gives evidence that a radical mechanism occurs involving the enzyme and/or coenzyme molecule as a hydrogen carrier. Such a biodegradation appears analogous to the conversion of 2-phenoxyethanol into acetate mediated by another strain of the anaerobic homoacetogenic bacterium Acetobacterium.

  13. Upflow anaerobic sludge blanket reactor--a review.

    PubMed

    Bal, A S; Dhagat, N N

    2001-04-01

    inorganic matter in the absence of molecular oxygen. Complex polymeric materials such as polysaccharides, proteins, and lipids (fat and grease) are first hydrolyzed to soluble products by extracellular enzymes, secreted by microorganisms, so as to facilitate their transport or diffusion across the cell membrane. These relatively simple, soluble compounds are fermented or anaerobically oxidized, further to short-chain fatty acids, alcohols, carbon dioxide, hydrogen, and ammonia. The short-chain fatty acids (other than acetate) are converted to acetate, hydrogen gas, and carbon dioxide. Methanogenesis finally occurs from the reduction of carbon dioxide and acetate by hydrogen. The initial stage of anaerobic degradation, i.e. acid fermentation is essentially a constant BOD stage because the organic molecules are only rearranged. The first stage does not stabilize the organics in the waste. However this step is essential for the initiation of second stage methane fermentation as it converts the organic material to a form, usable by the methane producing bacteria. The second reaction is initiated when anaerobic methane forming bacteria act upon the short chain organic acids produced in the 1st stage. Here these acids undergo methane fermentation with carbon dioxide acting as hydrogen acceptor and getting reduced to methane. The methane formed, being insoluble in water, escapes from the system and can be tapped and used as an energy source. The production and subsequent escape of methane causes the stabilization of the organic material. The methane-producing bacteria consist of several different groups. Each group has the ability to ferment only specific compounds. Therefore, the bacterial consortia in a methane producing system should include a number of different groups. When the rate of bacterial growth is considered, then the retention time of the solids becomes important parameter. The acid fermentation stage is faster as compared to the methane fermentation stage. This

  14. Anaerobic α-amylase production and secretion with fumarate as the final electron acceptor in Saccharomyces cerevisiae.

    PubMed

    Liu, Zihe; Österlund, Tobias; Hou, Jin; Petranovic, Dina; Nielsen, Jens

    2013-05-01

    In this study, we focus on production of heterologous α-amylase in the yeast Saccharomyces cerevisiae under anaerobic conditions. We compare the metabolic fluxes and transcriptional regulation under aerobic and anaerobic conditions, with the objective of identifying the final electron acceptor for protein folding under anaerobic conditions. We find that yeast produces more amylase under anaerobic conditions than under aerobic conditions, and we propose a model for electron transfer under anaerobic conditions. According to our model, during protein folding the electrons from the endoplasmic reticulum are transferred to fumarate as the final electron acceptor. This model is supported by findings that the addition of fumarate under anaerobic (but not aerobic) conditions improves cell growth, specifically in the α-amylase-producing strain, in which it is not used as a carbon source. Our results provide a model for the molecular mechanism of anaerobic protein secretion using fumarate as the final electron acceptor, which may allow for further engineering of yeast for improved protein secretion under anaerobic growth conditions.

  15. Starvation response of Saccharomyces cerevisiae grown in anaerobic nitrogen- or carbon-limited chemostat cultures.

    PubMed

    Thomsson, Elisabeth; Gustafsson, Lena; Larsson, Christer

    2005-06-01

    Anaerobic starvation conditions are frequent in industrial fermentation and can affect the performance of the cells. In this study, the anaerobic carbon or nitrogen starvation response of Saccharomyces cerevisiae was investigated for cells grown in anaerobic carbon or nitrogen-limited chemostat cultures at a dilution rate of 0.1 h(-1) at pH 3.25 or 5. Lactic or benzoic acid was present in the growth medium at different concentrations, resulting in 16 different growth conditions. At steady state, cells were harvested and then starved for either carbon or nitrogen for 24 h under anaerobic conditions. We measured fermentative capacity, glucose uptake capacity, intracellular ATP content, and reserve carbohydrates and found that the carbon, but not the nitrogen, starvation response was dependent upon the previous growth conditions. All cells subjected to nitrogen starvation retained a large portion of their initial fermentative capacity, independently of previous growth conditions. However, nitrogen-limited cells that were starved for carbon lost almost all their fermentative capacity, while carbon-limited cells managed to preserve a larger portion of their fermentative capacity during carbon starvation. There was a positive correlation between the amount of glycogen before carbon starvation and the fermentative capacity and ATP content of the cells after carbon starvation. Fermentative capacity and glucose uptake capacity were not correlated under any of the conditions tested. Thus, the successful adaptation to sudden carbon starvation requires energy and, under anaerobic conditions, fermentable endogenous resources. In an industrial setting, carbon starvation in anaerobic fermentations should be avoided to maintain a productive yeast population.

  16. Effect of long term anaerobic and intermittent anaerobic/aerobic starvation on aerobic granules.

    PubMed

    Pijuan, Maite; Werner, Ursula; Yuan, Zhiguo

    2009-08-01

    The effect of long term anaerobic and intermittent anaerobic/aerobic starvation on the structure and activity of aerobic granules was studied. Aerobic granular sludge treating abattoir wastewater and achieving high levels of nutrient removal was subjected to 4-5 week starvation under anaerobic and intermittent anaerobic/aerobic conditions. Microscopic pictures of granules at the beginning of the starvation period presented a round and compact surface morphology with a much defined external perimeter. Under both starvation conditions, the morphology changed at the end of starvation with the external border of the granules surrounded by floppy materials. The loss of granular compactness was faster and more pronounced under anaerobic/aerobic starvation conditions. The release of Ca(2+) at the onset of anaerobic/aerobic starvation suggests a degradation of extracellular polymeric substances. The activity of ammonia oxidizing bacteria was reduced by 20 and 36% during anaerobic and intermittent anaerobic/aerobic starvation, respectively. When fresh wastewater was reintroduced, the granules recovered their initial morphology within 1 week of normal operation and the nutrient removal activity recovered fully in 3 weeks. The results show that both anaerobic and intermittent anaerobic/aerobic conditions are suitable for maintaining granule structure and activity during starvation.

  17. In Vivo and In Vitro Anaerobic Mating in Candida albicans▿

    PubMed Central

    Dumitru, Raluca; Navarathna, Dhammika H. M. L. P.; Semighini, Camile P.; Elowsky, Christian G.; Dumitru, Razvan V.; Dignard, Daniel; Whiteway, Malcolm; Atkin, Audrey L.; Nickerson, Kenneth W.

    2007-01-01

    Candida albicans cells of opposite mating types are thought to conjugate during infection in mammalian hosts, but paradoxically, the mating-competent opaque state is not stable at mammalian body temperatures. We found that anaerobic conditions stabilize the opaque state at 37°C, block production of farnesol, and permit in vitro mating at 37°C at efficiencies of up to 84%. Aerobically, farnesol prevents mating because it kills the opaque cells necessary for mating, and as a corollary, farnesol production is turned off in opaque cells. These in vitro observations suggest that naturally anaerobic sites, such as the efficiently colonized gastrointestinal (GI) tract, could serve as niches for C. albicans mating. In a direct test of mating in the mouse GI tract, prototrophic cells were obtained from auxotrophic parent cells, confirming that mating will occur in this organ. These cells were true mating products because they were tetraploid, mononuclear, and prototrophic, and they contained the heterologous hisG marker from one of the parental strains. PMID:17259544

  18. Directed evolution of a cellodextrin transporter for improved biofuel production under anaerobic conditions in Saccharomyces cerevisiae.

    PubMed

    Lian, Jiazhang; Li, Yanglin; HamediRad, Mohammad; Zhao, Huimin

    2014-08-01

    Introduction of a cellobiose utilization pathway consisting of a cellodextrin transporter and a β-glucosidase into Saccharomyces cerevisiae enables co-fermentation of cellobiose and xylose. Cellodextrin transporter 1 (CDT1) from Neurospora crassa has been established as an effective transporter for the engineered cellobiose utilization pathways. However, cellodextrin transporter 2 (CDT2) from the same species is a facilitator and has the potential to be more efficient than CDT1 under anaerobic conditions due to its energetic benefits. Currently, CDT2 has a very low activity and is considered rate-limiting in cellobiose fermentation. Here, we report the directed evolution of CDT2 with an increased cellobiose uptake activity, which results in improved cellobiose fermentation under anaerobic conditions. After three rounds of directed evolution, the cellobiose uptake activity of CDT2 was increased by 2.2-fold, which resulted from both increased specific activity and transporter expression level. Using high cell density fermentation under anaerobic conditions, the evolved mutant conferred 4.0- and 4.4-fold increase in the cellobiose consumption rate and ethanol productivity, respectively. In addition, although the cellobiose uptake activity was still lower than that of CDT1, the engineered CDT2 showed significantly improved cellobiose consumption and ethanol production under anaerobic conditions, representing the energetic benefits of a sugar facilitator for anaerobic cellobiose fermentation. This study demonstrated that anaerobic biofuel production could be significantly improved via directed evolution of a sugar transporter protein in yeast.

  19. Anaerobic transformation of carbon monoxide by microbial communities of Kamchatka hot springs.

    PubMed

    Kochetkova, Tatiana V; Rusanov, Igor I; Pimenov, Nikolay V; Kolganova, Tatyana V; Lebedinsky, Alexander V; Bonch-Osmolovskaya, Elizaveta A; Sokolova, Tatyana G

    2011-05-01

    Carbon monoxide (CO) is one of the common gaseous compounds found in hot volcanic environments. It is known to serve as the growth substrate for a number of thermophilic prokaryotes, both aerobic and anaerobic. The goal of this work was to study the process of anaerobic transformation of CO by microbial communities inhabiting natural thermal environments: hot springs of Uzon Caldera, Kamchatka. The anaerobic microbial community of Treshchinny Spring (80°C, pH 6.5) was found to exhibit two peaks of affinity for CO (K (S1) = 54 nM and K (S2) = 1 μM). The actual rate of anaerobic CO transformation by the microbial community of this spring, calculated after obtaining the concentration dependence curve and extrapolated to the natural concentration of CO dissolved in the hot spring water (20 nM), was found to be 120 μmol l(-1) of sediment day(-1). In all the hot springs studied, more than 90% of the carbon of (14)CO upon anaerobic incubation was recovered as (14)CO(2). From 1 to 5% of (14)CO was transformed to volatile fatty acids (VFA). The number of microorganisms capable of anaerobic CO oxidation determined by dilution-to-extinction method reached 10(6) cells ml(-1) of sediment. CO-transforming anaerobic thermophilic microorganisms isolated from the springs under study exhibited hydrogenogenic type of CO oxidation and belonged to the bacterial genera Carboxydocella and Dictyoglomus. These data suggest a significant role of hydrogenogenic carboxydotrophic prokaryotes in anaerobic CO transformation in Uzon Caldera hot springs.

  20. Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae

    PubMed Central

    2011-01-01

    Background Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. Results We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. Conclusions Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked. PMID:21251255

  1. Anaerobic filter for biogas production

    NASA Astrophysics Data System (ADS)

    Chavadej, S.

    1980-01-01

    A laboratory study evaluated the performance of an anaerobic filter in producing biogas from pig waste with 30,000 mg/l of COD. The filter packing was bamboo rings of 1 and 1/2 in. diameter, 1 in. long; the bamboo-bed filter operated satisfactorily in a wide COD loading range of 3.74-15.65 kg/cu m/d which corresponds to the hydraulic retention of 8.47 to 1.68 days. At the optimum loading of 7.299 kg COD/cu m/d, the largest gas rate of 0.212 cu m/kg of COD was produced. The required volume of the digester for 1.2 cu m/d of gas production would be only 1.5 cu m; in practical applications, consideration should be given to the gas collecting system and clogging problems.

  2. Anaerobic digestion of alcohol stillage

    SciTech Connect

    Binder, L.K.

    1981-01-01

    In the production of ethanol from grain, the distillation step produces a residue of distillers grains or stillage that contains greater than 90% water and is currently dried and used as a cattle feed supplement. Experimental work was carried out on the anaerobic digestion of the stillage to determine the feasibility of using the CH/sub 4/ produced to supply the energy required in the ethanol distillation step. The fermentation characteristics of the stillage were studied, and the amount of CH/sub 4/ produced was determined. Based on an economic analysis, the value of the pressed solids fraction of the stillage as feed is much greater than the potential return from producing CH/sub 4/.

  3. Sleep deprivation induced anxiety and anaerobic performance.

    PubMed

    Vardar, Selma Arzu; Oztürk, Levent; Kurt, Cem; Bulut, Erdogan; Sut, Necdet; Vardar, Erdal

    2007-01-01

    The aim of this study was to investigate the effects of sleep deprivation induced anxiety on anaerobic performance. Thirteen volunteer male physical education students completed the Turkish version of State Anxiety Inventory and performed Wingate anaerobic test for three times: (1) following a full-night of habitual sleep (baseline measurements), (2) following 30 hours of sleep deprivation, and (3) following partial-night sleep deprivation. Baseline measurements were performed the day before total sleep deprivation. Measurements following partial sleep deprivation were made 2 weeks later than total sleep deprivation measurements. State anxiety was measured prior to each Wingate test. The mean state anxiety following total sleep deprivation was higher than the baseline measurement (44.9 ± 12.9 vs. 27.6 ± 4.2, respectively, p = 0.02) whereas anaerobic performance parameters remained unchanged. Neither anaerobic parameters nor state anxiety levels were affected by one night partial sleep deprivation. Our results suggest that 30 hours continuous wakefulness may increase anxiety level without impairing anaerobic performance, whereas one night of partial sleep deprivation was ineffective on both state anxiety and anaerobic performance. Key pointsShort time total sleep deprivation (30 hours) increases state anxiety without any competition stress.Anaerobic performance parameters such as peak power, mean power and minimum power may not show a distinctive difference from anaerobic performance in a normal sleep day despite the high anxiety level induced by short time sleep deprivation.Partial sleep deprivation does not affect anxiety level and anaerobic performance of the next day.

  4. Gram-Positive Anaerobic Cocci

    PubMed Central

    Murdoch, D. A.

    1998-01-01

    Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of organisms defined by their morphological appearance and their inability to grow in the presence of oxygen; most clinical isolates are identified to species in the genus Peptostreptococcus. GPAC are part of the normal flora of all mucocutaneous surfaces and are often isolated from infections such as deep organ abscesses, obstetric and gynecological sepsis, and intraoral infections. They have been little studied for several reasons, which include an inadequate classification, difficulties with laboratory identification, and the mixed nature of the infections from which they are usually isolated. Nucleic acid studies indicate that the classification is in need of radical revision at the genus level. Several species of Peptostreptococcus have recently been described, but others still await formal recognition. Identification has been based on carbohydrate fermentation tests, but most GPAC are asaccharolytic and use the products of protein degradation for their metabolism; the introduction of commercially available preformed enzyme kits affords a physiologically more appropriate method of identification, which is simple and relatively rapid and can be used in routine diagnostic laboratories. Recent reports have documented the isolation in pure culture of several species, notably Peptostreptococcus magnus, from serious infections. Studies of P. magnus have elucidated several virulence factors which correlate with the site of infection, and reveal some similarities to Staphylococcus aureus. P. micros is a strongly proteolytic species; it is increasingly recognized as an important pathogen in intraoral infections, particularly periodontitis, and mixed anaerobic deep-organ abscesses. Comparison of antibiotic susceptibility patterns reveals major differences between species. Penicillins are the antibiotics of choice, although some strains of P. anaerobius show broad-spectrum β-lactam resistance. PMID:9457430

  5. Energy from anaerobic methane production. [Sweden

    SciTech Connect

    Not Available

    1982-02-01

    Since 1970 Swedish researchers have been testing the ANAMET (anaerobic-aerobic-methane) process, which involves converting industrial wastewaters via an initial anaerobic microbiological step followed by an aerobic one. Recycling the biomass material in each step allows shorter hydraulic retention times without decreasing stability or solids reduction. Since the first ANAMET plants began operating at a Swedish sugar factory in 1972, 17 more plants have started up or are under construction. Moreover, the ANAMET process has engendered to offshoot BIOMET (biomass-methane) process, a thermophilic anaerobic scheme that can handle sugar-beet pulp as well as grass and other soft, fast-growing biomasses.

  6. Fate of Trace Metals in Anaerobic Digestion.

    PubMed

    Fermoso, F G; van Hullebusch, E D; Guibaud, G; Collins, G; Svensson, B H; Carliell-Marquet, C; Vink, J P M; Esposito, G; Frunzo, L

    2015-01-01

    A challenging, and largely uncharted, area of research in the field of anaerobic digestion science and technology is in understanding the roles of trace metals in enabling biogas production. This is a major knowledge gap and a multifaceted problem involving metal chemistry; physical interactions of metal and solids; microbiology; and technology optimization. Moreover, the fate of trace metals, and the chemical speciation and transport of trace metals in environments--often agricultural lands receiving discharge waters from anaerobic digestion processes--simultaneously represents challenges for environmental protection and opportunities to close process loops in anaerobic digestion.

  7. Microbial physiology of an anaerobic propionate-degrading consortium

    SciTech Connect

    Xun, L.

    1989-01-01

    A methanogenic propionate-degrading consortium, comprised of a strictly anaerobic chemoheterotroph and two types of methanogenic bacteria, is responsible for the complete conversion of propionate to CH{sub 4} and CO{sub 2} via the intermediate formation of acetate, H{sub 2}, and CO{sub 2}. Propionate oxidation by the heterotroph to acetate, H{sub 2} and CO{sub 2} proceeds only if H{sub 2} is removed through oxidation by CO{sub 2}-reducing methanogens. Acetate may only be catabolized anaerobically by one specific physiological group of bacteria, the aceticlastic methanogens, which produces CH{sub 4} and CO{sub 2} by cleaving acetate. Representatives of all three of these organisms have been studied. The effects of environmental factors such as temperature, pH, and nutrients on anaerobic propionate degradation was studied by enrichment cultures. From the propionate enrichment, the H{sub 2} using methanogen (strain LX1) and the propionate-degrading organism (strain LX2) were isolated. Both organisms have been characterized. In regard to the aceticlastic reaction, Methanosarcina mazei S-6 isolated by Mah (1980), was studied as the third member of the consortium. By changing the culture conditions, the morphology of M. mazei was manipulated from an aggregated to single cell form.

  8. Anaerobic Mercury Methylation and Demethylation by Geobacter bemidjiensis Bem.

    PubMed

    Lu, Xia; Liu, Yurong; Johs, Alexander; Zhao, Linduo; Wang, Tieshan; Yang, Ziming; Lin, Hui; Elias, Dwayne A; Pierce, Eric M; Liang, Liyuan; Barkay, Tamar; Gu, Baohua

    2016-04-19

    Microbial methylation and demethylation are two competing processes controlling the net production and bioaccumulation of neurotoxic methylmercury (MeHg) in natural ecosystems. Although mercury (Hg) methylation by anaerobic microorganisms and demethylation by aerobic Hg-resistant bacteria have both been extensively studied, little attention has been given to MeHg degradation by anaerobic bacteria, particularly the iron-reducing bacterium Geobacter bemidjiensis Bem. Here we report, for the first time, that the strain G. bemidjiensis Bem can mediate a suite of Hg transformations, including Hg(II) reduction, Hg(0) oxidation, MeHg production and degradation under anoxic conditions. Results suggest that G. bemidjiensis utilizes a reductive demethylation pathway to degrade MeHg, with elemental Hg(0) as the major reaction product, possibly due to the presence of genes encoding homologues of an organomercurial lyase (MerB) and a mercuric reductase (MerA). In addition, the cells can strongly sorb Hg(II) and MeHg, reduce or oxidize Hg, resulting in both time and concentration-dependent Hg species transformations. Moderate concentrations (10-500 μM) of Hg-binding ligands such as cysteine enhance Hg(II) methylation but inhibit MeHg degradation. These findings indicate a cycle of Hg methylation and demethylation among anaerobic bacteria, thereby influencing net MeHg production in anoxic water and sediments.

  9. PGM2 overexpression improves anaerobic galactose fermentation in Saccharomyces cerevisiae

    PubMed Central

    2010-01-01

    Background In Saccharomyces cerevisiae galactose is initially metabolized through the Leloir pathway after which glucose 6-phosphate enters glycolysis. Galactose is controlled both by glucose repression and by galactose induction. The gene PGM2 encodes the last enzyme of the Leloir pathway, phosphoglucomutase 2 (Pgm2p), which catalyses the reversible conversion of glucose 1-phosphate to glucose 6-phosphate. Overexpression of PGM2 has previously been shown to enhance aerobic growth of S. cerevisiae in galactose medium. Results In the present study we show that overexpression of PGM2 under control of the HXT7'promoter from an integrative plasmid increased the PGM activity 5 to 6 times, which significantly reduced the lag phase of glucose-pregrown cells in an anaerobic galactose culture. PGM2 overexpression also increased the anaerobic specific growth rate whereas ethanol production was less influenced. When PGM2 was overexpressed from a multicopy plasmid instead, the PGM activity increased almost 32 times. However, this increase of PGM activity did not further improve aerobic galactose fermentation as compared to the strain carrying PGM2 on the integrative plasmid. Conclusion PGM2 overexpression in S. cerevisiae from an integrative plasmid is sufficient to reduce the lag phase and to enhance the growth rate in anaerobic galactose fermentation, which results in an overall decrease in fermentation duration. This observation is of particular importance for the future development of stable industrial strains with enhanced PGM activity. PMID:20507616

  10. Cellulose fermentation by nitrogen-fixing anaerobic bacteria

    SciTech Connect

    Canale-Parola, E.

    1992-12-13

    In anaerobic natural environments cellulose is degraded to methane, carbon dioxide and other products by the combined activities of many diverse microorganisms. We are simulating processes occurring in natural environments by constructing biologically-defined, stable, heterogeneous bacterial communities (consortia) that we use as in vitro systems for quantitative studies of cellulose degradation under conditions of combined nitrogen deprivation. These studies include the investigation of (i) metabolic interactions among members of cellulose-degrading microbial populations, and (ii) processes that regulate the activity or biosynthesis of cellulolytic enzymes. In addition, we are studying the sensory mechanisms that, in natural environments, may enable motile cellulolytic bacteria to migrate toward cellulose. This part of our work includes biochemical characterization of the cellobiose chemoreceptor of cellulolytic bacteria. Finally, an important aspect of our research is the investigation of the mechanisms by which multienzyme complexes of anaerobic bacteria catalyze the depolymerization of crystalline cellulose and of other plant cell wall polysacchaddes. The research will provide fundamental information on the physiology and ecology of cellulose-fermenting, N{sub 2}-fixing bacteria, and on the intricate processes involved in C and N cycling in anaerobic environments. Furthermore, the information will be valuable for the development of practical applications, such as the conversion of plant biomass (e.g., agricultural, forestry and municipal wastes) to automotive fuels such as ethanol.

  11. Structure of a cellulose degrading bacterial community during anaerobic digestion.

    PubMed

    O'Sullivan, Cathryn A; Burrell, Paul C; Clarke, William P; Blackall, Linda L

    2005-12-30

    It is widely accepted that cellulose is the rate-limiting substrate in the anaerobic digestion of organic solid wastes and that cellulose solubilisation is largely mediated by surface attached bacteria. However, little is known about the identity or the ecophysiology of cellulolytic microorganisms from landfills and anaerobic digesters. The aim of this study was to investigate an enriched cellulolytic microbial community from an anaerobic batch reactor. Chemical oxygen demand balancing was used to calculate the cellulose solubilisation rate and the degree of cellulose solubilisation. Fluorescence in situ hybridisation (FISH) was used to assess the relative abundance and physical location of three groups of bacteria belonging to the Clostridium lineage of the Firmicutes that have been implicated as the dominant cellulose degraders in this system. Quantitation of the relative abundance using FISH showed that there were changes in the microbial community structure throughout the digestion. However, comparison of these results to the process data reveals that these changes had no impact on the cellulose solubilisation in the reactor. The rate of cellulose solubilisation was approximately stable for much of the digestion despite changes in the cellulolytic population. The solubilisation rate appears to be most strongly affected by the rate of surface area colonisation and the biofilm architecture with the accepted model of first order kinetics due to surface area limitation applying only when the cellulose particles are fully covered with a thin layer of cells.

  12. Stabilisation of microalgae: Iodine mobilisation under aerobic and anaerobic conditions.

    PubMed

    Han, Wei; Clarke, William; Pratt, Steven

    2015-10-01

    Mobilisation of iodine during microalgae stabilisation was investigated, with the view of assessing the potential of stabilised microalgae as an iodine-rich fertiliser. An iodine-rich waste microalgae (0.35 ± 0.05 mg I g(-1) VS(added)) was stabilised under aerobic and anaerobic conditions. Iodine mobilisation was linearly correlated with carbon emission, indicating iodine was in the form of organoiodine. Comparison between iodine and nitrogen mobilisation relative to carbon emission indicated that these elements were, at least in part, housed separately within the cells. After stabilisation, there were 0.22 ± 0.05 and 0.19 ± 0.01 mg g(-1) VS(added) iodine remaining in the solid in the aerobic and anaerobic processed material respectively, meaning 38 ± 5.0% (aerobic) and 50 ± 8.6% (anaerobic) of the iodine were mobilised, and consequently lost from the material. The iodine content of the stabilised material is comparable to the iodine content of some seaweed fertilisers, and potentially satisfies an efficient I-fertilisation dose.

  13. Reduction of Nitrated Diphenylamine Derivatives under Anaerobic Conditions

    PubMed Central

    Drzyzga, O.; Schmidt, A.; Blotevogel, K.

    1995-01-01

    2-Nitrodiphenylamine, 4-nitrodiphenylamine, and 2,4-dinitrodiphenylamine were anaerobically metabolized in sediment-water batch enrichments inoculated with mud from the German North Sea coast. The first intermediate in 2,4-dinitrodiphenylamine degradation was 2-amino-4-nitrodiphenylamine, which appeared in large (nearly stoichiometric) amounts before being completely reduced to 2,4-diaminodiphenylamine. Of the second theoretically expected metabolite, 4-amino-2-nitrodiphenylamine, only traces were detected by gas chromatographic-mass spectrometric analysis in highly concentrated extracts. In addition, low levels of 4-nitrodiphenylamine, which may be the product of ortho deamination of intermediately produced 2-amino-4-nitrodiphenylamine, were observed. 2-Nitrodiphenylamine and 4-nitrodiphenylamine were primarily reduced to 2-aminodiphenylamine and 4-aminodiphenylamine, respectively. Diphenylamine was never detected in any experiment as a theoretically possible intermediate. Results from studies with dense cell suspensions of anaerobic, aromatic-compound-mineralizing bacteria confirmed the transformation reactions, which were carried out by microorganisms indigenous to the anaerobic coastal water sediment. PMID:16535118

  14. Metagenome of an Anaerobic Microbial Community Decomposing Poplar Wood Chips

    SciTech Connect

    van der Lelie, D.; Taghavi, S.; McCorkle, S. M.; Li, L. L.; Malfatti, S. A.; Monteleone, D.; Donohoe, B. S.; Ding, S. Y.; Adney, W. S.; Himmel, M. E.; Tringe, S. G.

    2012-05-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic 'secretomes' that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to

  15. Optical sorting and cultivation of denitrifying anaerobic methane oxidation archaea

    PubMed Central

    Qi, Xiaoqiong; Carberry, David M.; Cai, Chen; Hu, Shihu; Yuan, Zhiguo; Dunlop, Halin Rubinsztein; Guo, Jianhua

    2017-01-01

    Denitrifying anaerobic methane oxidizing (DAMO) microorganisms play an important role in the global carbon and nitrogen cycles as they are able to mediate methane oxidation using nitrite/nitrate under anoxic conditions. However, the physiological properties of DAMO microorganisms remain poorly understood, partially since the organisms are difficult to isolate or cultivate in pure culture and partially because of their long cultivation time. In this study, DAMO cell sorting has been conducted by integrating optical tweezers within enclosed microfluidic chips. This integrated cell sorting method has high purity, low infection rates, and causes no discernable harm to cell viability. The purity of the sorted cells was controlled by the microfluidic chip structure design and operation, while the cell viability was verified by imaging the cultured DAMO archaea after 420 days. PMID:28270994

  16. Anaerobes in Industrial- and Environmental Biotechnology.

    PubMed

    Hatti-Kaul, Rajni; Mattiasson, Bo

    Anaerobic microorganisms present in diverse ecological niches employ alternative strategies for energy conservation in the absence of oxygen which enables them to play a key role in maintaining the global cycles of carbon, nitrogen, and sulfur, and the breakdown of persistent compounds. Thereby they become useful tools in industrial and environmental biotechnology. Although anaerobes have been relatively neglected in comparison to their aerobic counterparts, with increasing knowledge about their diversity and metabolic potential and the development of genetic tools and process technologies to utilize them, we now see a rapid expansion of their applications in the society. This chapter summarizes some of the developments in the use of anaerobes as tools for biomass valorization, in production of energy carriers and chemicals, wastewater treatment, and the strong potential in soil remediation. The ability of several autotrophic anaerobes to reduce carbon dioxide is attracting growing attention as a means for developing a platform for conversion of waste gases to chemicals, materials, and biofuels.

  17. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  18. The Role of Short-Chain Fatty Acids, Produced by Anaerobic Bacteria, in the Cystic Fibrosis Airway

    PubMed Central

    Murray, Michelle A.; Lavelle, Gillian M.; Molloy, Kevin; Azim, Ahmed Abdul; Gunaratnam, Cedric; Healy, Fiona; Slattery, Dubhfeasa; McNally, Paul; Hatch, Joe; Wolfgang, Matthew; Tunney, Michael M.; Muhlebach, Marianne S.; Devery, Rosaleen; Greene, Catherine M.; McElvaney, Noel G.

    2015-01-01

    Rationale: Anaerobic bacteria are present in large numbers in the airways of people with cystic fibrosis (PWCF). In the gut, anaerobes produce short-chain fatty acids (SCFAs) that modulate immune and inflammatory processes. Objectives: To investigate the capacity of anaerobes to contribute to cystic fibrosis (CF) airway pathogenesis via SCFAs. Methods: Samples of 109 PWCF were processed using anaerobic microbiological culture with bacteria present identified by 16S RNA sequencing. SCFA levels in anaerobic supernatants and bronchoalveolar lavage (BAL) were determined by gas chromatography. The mRNA and/or protein expression of two SCFA receptors, GPR41 and GPR43, in CF and non-CF bronchial brushings and 16HBE14o− and CFBE41o− cells were evaluated using reverse transcription polymerase chain reaction, Western blot analysis, laser scanning cytometry, and confocal microscopy. SCFA-induced IL-8 secretion was monitored by ELISA. Measurements and Main Results: Fifty-seven (52.3%) of 109 PWCF were anaerobe positive. Prevalence increased with age, from 33.3% to 57.7% in PWCF younger (n = 24) and older (n = 85) than 6 years of age. All evaluated anaerobes produced millimolar concentrations of SCFAs, including acetic, propionic, and butyric acids. SCFA levels were higher in BAL samples of adults than in those of children. GPR41 levels were elevated in CFBE41o− versus 16HBE14o− cells; CF versus non-CF bronchial brushings; and 16HBE14o− cells after treatment with cystic fibrosis transmembrane conductance regulator inhibitor CFTR(inh)-172, CF BAL, or inducers of endoplasmic reticulum stress. SCFAs induced a dose-dependent and pertussis toxin–sensitive IL-8 response in bronchial epithelial cells, with a higher production of IL-8 in CFBE41o− than in 16HBE14o− cells. Conclusions: This study illustrates that SCFAs contribute to excessive production of IL-8 in CF airways colonized with anaerobes via up-regulated GPR41. PMID:26266556

  19. An Evaluation of Tests of Anaerobic Power,

    DTIC Science & Technology

    1985-12-01

    constitutes an important component of physical exercise with great practical implications. Until recently, the assessment of anaerobic capacity has been...anaerobic physical exercise . * 6 .". 2 The development of procedures for measuring the ability of human muscle to generate power during high-intensity...the WT and IET represent valid laboratory tests for evaluitlng high-intensity short-term exercise In which the muscle is primarily dependent upon

  20. Hydrogen evolution by strictly aerobic hydrogen bacteria under anaerobic conditions.

    PubMed

    Kuhn, M; Steinbüchel, A; Schlegel, H G

    1984-08-01

    When strains and mutants of the strictly aerobic hydrogen-oxidizing bacterium Alcaligenes eutrophus are grown heterotrophically on gluconate or fructose and are subsequently exposed to anaerobic conditions in the presence of the organic substrates, molecular hydrogen is evolved. Hydrogen evolution started immediately after the suspension was flushed with nitrogen, reached maximum rates of 70 to 100 mumol of H2 per h per g of protein, and continued with slowly decreasing rates for at least 18 h. The addition of oxygen to an H2-evolving culture, as well as the addition of nitrate to cells (which had formed the dissimilatory nitrate reductase system during the preceding growth), caused immediate cessation of hydrogen evolution. Formate is not the source of H2 evolution. The rates of H2 evolution with formate as the substrate were lower than those with gluconate. The formate hydrogenlyase system was not detectable in intact cells or crude cell extracts. Rather the cytoplasmic, NAD-reducing hydrogenase is involved by catalyzing the release of excessive reducing equivalents under anaerobic conditions in the absence of suitable electron acceptors. This conclusion is based on the following experimental results. H2 is formed only by cells which had synthesized the hydrogenases during growth. Mutants lacking the membrane-bound hydrogenase were still able to evolve H2. Mutants lacking the NAD-reducing or both hydrogenases were unable to evolve H2.

  1. Measurement of anaerobic work capacities in humans.

    PubMed

    Green, S

    1995-01-01

    The development of simple, noninvasive tests of work capacities, underpinned primarily by anaerobic metabolism, proliferated in the early 1970s. A 30-second maximal cycle test developed at the Wingate Institute initiated efforts to develop work tests of anaerobic capacities. Such tests can be developed using any ergometer which simulates competitive conditions and enables an accurate determination of mechanical work output. A 10-second all-out test is commonly used to measure maximal work output generated primarily via the hydrolysis of high-energy phosphagens (i.e. the alactic work capacity). In contrast, a variety of constant-load and all-out tests of anaerobic (alactic plus lactic) work capacity have been proposed. It has been suggested that all-out tests provide more information about physiological capabilities and are easier to apply than constant-load tests. The optimal duration for an all-out test of anaerobic work capacity is proposed at 30 seconds, a duration which may also provide the basis for the development of accurate field tests of anaerobic capacity. There is evidence that the y-intercept of the maximal work-derivation regression is a valid work estimate of anaerobic capacity in athletes, although its utility is undermined by the number of tests required for its derivation.

  2. Anaerobic electron acceptor chemotaxis in Shewanella putrefaciens.

    PubMed

    Nealson, K H; Moser, D P; Saffarini, D A

    1995-04-01

    Shewanella putrefaciens MR-1 can grow either aerobically or anaerobically at the expense of many different electron acceptors and is often found in abundance at redox interfaces in nature. Such redox interfaces are often characterized by very strong gradients of electron acceptors resulting from rapid microbial metabolism. The coincidence of S. putrefaciens abundance with environmental gradients prompted an examination of the ability of MR-1 to sense and respond to electron acceptor gradients in the laboratory. In these experiments, taxis to the majority of the electron acceptors that S. putrefaciens utilizes for anaerobic growth was seen. All anaerobic electron acceptor taxis was eliminated by the presence of oxygen, nitrate, nitrite, elemental sulfur, or dimethyl sulfoxide, even though taxis to the latter was very weak and nitrate and nitrite respiration was normal in the presence of dimethyl sulfoxide. Studies with respiratory mutants of MR-1 revealed that several electron acceptors that could not be used for anaerobic growth nevertheless elicited normal anaerobic taxis. Mutant M56, which was unable to respire nitrite, showed normal taxis to nitrite, as well as the inhibition of taxis to other electron acceptors by nitrite. These results indicate that electron acceptor taxis in S. putrefaciens does not conform to the paradigm established for Escherichia coli and several other bacteria. Carbon chemo-taxis was also unusual in this organism: of all carbon compounds tested, the only positive response observed was to formate under anaerobic conditions.

  3. Anaerobic electron acceptor chemotaxis in Shewanella putrefaciens

    NASA Technical Reports Server (NTRS)

    Nealson, K. H.; Moser, D. P.; Saffarini, D. A.

    1995-01-01

    Shewanella putrefaciens MR-1 can grow either aerobically or anaerobically at the expense of many different electron acceptors and is often found in abundance at redox interfaces in nature. Such redox interfaces are often characterized by very strong gradients of electron acceptors resulting from rapid microbial metabolism. The coincidence of S. putrefaciens abundance with environmental gradients prompted an examination of the ability of MR-1 to sense and respond to electron acceptor gradients in the laboratory. In these experiments, taxis to the majority of the electron acceptors that S. putrefaciens utilizes for anaerobic growth was seen. All anaerobic electron acceptor taxis was eliminated by the presence of oxygen, nitrate, nitrite, elemental sulfur, or dimethyl sulfoxide, even though taxis to the latter was very weak and nitrate and nitrite respiration was normal in the presence of dimethyl sulfoxide. Studies with respiratory mutants of MR-1 revealed that several electron acceptors that could not be used for anaerobic growth nevertheless elicited normal anaerobic taxis. Mutant M56, which was unable to respire nitrite, showed normal taxis to nitrite, as well as the inhibition of taxis to other electron acceptors by nitrite. These results indicate that electron acceptor taxis in S. putrefaciens does not conform to the paradigm established for Escherichia coli and several other bacteria. Carbon chemo-taxis was also unusual in this organism: of all carbon compounds tested, the only positive response observed was to formate under anaerobic conditions.

  4. Hydrogenispora ethanolica gen. nov., sp. nov., an anaerobic carbohydrate-fermenting bacterium from anaerobic sludge.

    PubMed

    Liu, Yi; Qiao, Jiang-Tao; Yuan, Xian-Zheng; Guo, Rong-Bo; Qiu, Yan-Ling

    2014-05-01

    An anaerobic, spore-forming, ethanol-hydrogen-coproducing bacterium, designated LX-BT, was isolated from an anaerobic sludge treating herbicide wastewater. Cells of strain LX-BT were non-motile rods (0.3-0.5×3.0-18.0 µm). Spores were terminal with a bulged sporangium. Growth occurred at 20-50 °C (optimum 37-45 °C), pH 5.0-8.0 (optimum pH 6.0-7.7) and 0-2.5% (w/v) NaCl. The strain could grow fermentatively on glucose, maltose, arabinose, fructose, xylose, ribose, galactose, mannose, raffinose, sucrose, pectin, starch, glycerol, fumarate, tryptone and yeast extract. The major end-products of glucose fermentation were acetate, ethanol and hydrogen. Yeast extract was not required but stimulated growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, anthraquinone-2,6-disulfonate, fumarate and Fe (III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of the genomic DNA was 56.1 mol%. The major cellular fatty acids were anteiso-C15:0, iso-C14:0 and C16:0. The most abundant polar lipids of strain LX-BT were diphosphatidylglycerol and phosphatidylglycerol. 16S rRNA gene sequence analysis revealed that it belongs to an as-yet-unidentified taxon at the order- or class-level (OPB54) within the phylum Firmicutes, showing 86.5% sequence similarity to previously described species of the Desulfotomaculum cluster. The name Hydrogenispora ethanolica gen. nov., sp. nov. is proposed to accommodate strain LX-BT (=DSM 25471T=JCM 18117T=CGMCC 1.5175T) as the type strain.

  5. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  6. Isolation and Characterization of an Enterobacter cloacae Strain That Reduces Hexavalent Chromium under Anaerobic Conditions

    PubMed Central

    Wang, Pi-Chao; Mori, Tsukasa; Komori, Kohya; Sasatsu, Masanori; Toda, Kiyoshi; Ohtake, Hisao

    1989-01-01

    An Enterobacter cloacae strain (HO1) capable of reducing hexavalent chromium (chromate) was isolated from activated sludge. This bacterium was resistant to chromate under both aerobic and anaerobic conditions. Only the anaerobic culture of the E. cloacae isolate showed chromate reduction. In the anaerobic culture, yellow turned white with chromate and the turbidity increased as the reduction proceeded, suggesting that insoluble chromium hydroxide was formed. E. cloacae is likely to utilize toxic chromate as an electron acceptor anaerobically because (i) the anaerobic growth of E. cloacae HO1 accompanied the decrease of toxic chromate in culture medium, (ii) the chromate-reducing activity was rapidly inhibited by oxygen, and (iii) the reduction occurred more rapidly in glycerol- or acetate-grown cells than in glucose-grown cells. The chromate reduction in E. cloacae HO1 was observed at pH 6.0 to 8.5 (optimum pH, 7.0) and at 10 to 40°C (optimum, 30°C). PMID:16347962

  7. Anaerobic, Nitrate-Dependent Oxidation of U(IV) Oxide Minerals by the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

    PubMed Central

    Beller, Harry R.

    2005-01-01

    Under anaerobic conditions and at circumneutral pH, cells of the widely distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated with nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium. PMID:15812053

  8. Anaerobic, Nitrate-Dependent Oxidation of U(IV) Oxide Minerals by the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

    SciTech Connect

    Beller, H R

    2004-06-25

    Under anaerobic conditions and at circumneutral pH, cells of the widely-distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated to nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium.

  9. Anaerobic utilization of phosphite and hypophosphite by Bacillus sp.

    NASA Technical Reports Server (NTRS)

    Foster, T. L.; Winans, L., Jr.; Helms, S. J. S.

    1978-01-01

    A Bacillus species capable of using phosphite and hypophosphite under anaerobic conditions was isolated from Cape Canaveral soil samples and grown on a glucose-mineral salts medium with phosphate omitted. The optimum hypophosphite concentration was 60 microg/ml, while the optimum phosphite concentration was greater than 1000 microg/ml. P-32-labeled hypophosphite was incorporated into the cell as organic phosphate, and little or no phosphate appeared in the medium when either hypophosphite or phosphite was the phosphorus source. When phosphate was present in the medium, phosphite was not metabolized. When both phosphite and hypophosphite were present, phosphite was used first and then hypophosphite.

  10. Anaerobic Nitrogen Fixers on Mars

    NASA Astrophysics Data System (ADS)

    Lewis, B. G.

    2000-07-01

    The conversion of atmospheric nitrogen gas to the protein of living systems is an amazing process of nature. The first step in the process is biological nitrogen fixation, the transformation of N2 to NH3. The phenomenon is crucial for feeding the billions of our species on Earth. On Mars, the same process may allow us to discover how life can adapt to a hostile environment, and render it habitable. Hostile environments also exist on Earth. For example, nothing grows in coal refuse piles due to the oxidation of pyrite and marcasite to sulfuric acid. Yet, when the acidity is neutralized, alfalfa and soybean plants develop root nodules typical of symbiotic nitrogen fixation with Rhizobium species possibly living in the pyritic material. When split open, these nodules exhibited the pinkish color of leghemoglobin, a protein in the nodule protecting the active nitrogen-fixing enzyme nitrogenase against the toxic effects of oxygen. Although we have not yet obtained direct evidence of nitrogenase activity in these nodules (reduction of acetylene to ethylene, for example), these findings suggested the possibility that nitrogen fixation was taking place in this hostile, non-soil material. This immediately raises the possibility that freeliving anaerobic bacteria which fix atmospheric nitrogen on Earth, could do the same on Mars.

  11. Hemicellulose conversion by anaerobic digestion

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Christopher, R.W.

    1982-01-01

    The digestibility of an aquatic biomass (water hyacinth), a land-based biomass (Coastal Bermuda grass), and a biomass-waste blend (a mixture of hyacinth, grass, MSW, and sludge) under various digestion conditions was studied. Anaerobic digestion of hemicellulose consists of the steps of enzymatic hydrolysis of hemicellulose to glucans, mannans, galactans, xylans, and arabans, and then to simple hexose and pentose sugars; production of C/sub 2/ and higher fatty acids from the simple sugars; conversion of higher fatty acids to acetate; and finally, production of methane and CO/sub 2/ from acetate, and CO/sub 2/ and hydrogen. The conversion of hemicellulose was higher under mesophilic conditions than those of cellulose or protein for all biomass test feeds, probably because the hemicellulose structure was more vulnerable to enzymatic attack than that of the lignocellulosic component. Cellulose conversion efficiencies at the mesophilic and thermophilic temperatures were about the same. However, hemicellulose was converted at a much lower efficiency than cellulose during thermophilic digestion - a situation that was the reverse of that observed at the mesophilic temperature. Cellulose was utilized in preference to hemicellulose during mesophilic digestion of nitrogen-supplemented Bermuda grass. It was speculated that Bermuda grass cellulose was converted at a higher efficiency than hemicellulose in the presence of external nitrogen because the metabolism of the breakdown product (glucose) of cellulose requires the least investment of enzymes and energy.

  12. Medium factors on anaerobic production of rhamnolipids by Pseudomonas aeruginosa SG and a simplifying medium for in situ microbial enhanced oil recovery applications.

    PubMed

    Zhao, Feng; Zhou, Jidong; Han, Siqin; Ma, Fang; Zhang, Ying; Zhang, Jie

    2016-04-01

    Aerobic production of rhamnolipid by Pseudomonas aeruginosa was extensively studied. But effect of medium composition on anaerobic production of rhamnolipid by P. aeruginosa was unknown. A simplifying medium facilitating anaerobic production of rhamnolipid is urgently needed for in situ microbial enhanced oil recovery (MEOR). Medium factors affecting anaerobic production of rhamnolipid were investigated using P. aeruginosa SG (Genbank accession number KJ995745). Medium composition for anaerobic production of rhamnolipid by P. aeruginosa is different from that for aerobic production of rhamnolipid. Both hydrophobic substrate and organic nitrogen inhibited rhamnolipid production under anaerobic conditions. Glycerol and nitrate were the best carbon and nitrogen source. The commonly used N limitation under aerobic conditions was not conducive to rhamnolipid production under anaerobic conditions because the initial cell growth demanded enough nitrate for anaerobic respiration. But rhamnolipid was also fast accumulated under nitrogen starvation conditions. Sufficient phosphate was needed for anaerobic production of rhamnolipid. SO4(2-) and Mg(2+) are required for anaerobic production of rhamnolipid. Results will contribute to isolation bacteria strains which can anaerobically produce rhamnolipid and medium optimization for anaerobic production of rhamnolipid. Based on medium optimization by response surface methodology and ions composition of reservoir formation water, a simplifying medium containing 70.3 g/l glycerol, 5.25 g/l NaNO3, 5.49 g/l KH2PO4, 6.9 g/l K2HPO4·3H2O and 0.40 g/l MgSO4 was designed. Using the simplifying medium, 630 mg/l of rhamnolipid was produced by SG, and the anaerobic culture emulsified crude oil to EI24 = 82.5 %. The simplifying medium was promising for in situ MEOR applications.

  13. Isolation, Culture Characteristics, and Identification of Anaerobic Bacteria from the Chicken Cecum

    PubMed Central

    Salanitro, J. P.; Fairchilds, I. G.; Zgornicki, Y. D.

    1974-01-01

    Studies on the anaerobic cecal microflora of the 5-week-old chicken were made to determine a suitable roll-tube medium for enumeration and isolation of the bacterial population, to determine effects of medium components on recovery of total anaerobes, and to identify the predominant bacterial groups. The total number of microorganisms in cecal contents determined by direct microscope cell counts varied (among six samples) from 3.83 × 1010 to 7.64 × 1010 per g. Comparison of different nonselective media indicated that 60% of the direct microscope count could be recovered with a rumen fluid medium (M98-5) and 45% with medium 10. Deletion of rumen fluid from M98-5 reduced the total anaerobic count by half. Colony counts were lower if chicken cecal extract was substituted for rumen fluid in M98-5. Supplementing medium 10 with liver, chicken fecal, or cecal extracts improved recovery of anaerobes slightly. Prereduced blood agar media were inferior to M98-5. At least 11 groups of bacteria were isolated from high dilutions (10-9) of cecal material. Data on morphology and physiological and fermentation characteristics of 90% of the 298 isolated strains indicated that these bacteria represented species of anaerobic gram-negative cocci, facultatively anaerobic cocci and streptococci, Peptostreptococcus, Propionibacterium, Eubacterium, Bacteroides, and Clostridium. The growth of many of these strains was enhanced by rumen fluid, yeast extract, and cecal extract additions to basal media. These studies indicate that some of the more numerous anaerobic bacteria present in chicken cecal digesta can be isolated and cultured when media and methods that have been developed for ruminal bacteria are employed. PMID:4596749

  14. Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions.

    PubMed

    Benadé, Eliska; Stone, Wendy; Mouton, Marnel; Postma, Ferdinand; Wilsenach, Jac; Botha, Alfred

    2016-04-01

    We used both aerobic and anaerobic liquid co-cultures, prepared with Luria Bertani broth, to study the effect of bacteria on the survival of Candida albicans in the external environment, away from an animal host. The bacteria were represented by Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Clostridium, Enterobacter, Klebsiella pneumoniae, Kluyvera ascorbata and Serratia marcescens. Under aerobic conditions, the yeast's growth was inhibited in the presence of bacterial growth; however, under anaerobic conditions, yeast and bacterial growth in co-cultures was similar to that observed for pure cultures. Subsequent assays revealed that the majority of bacterial strains aerobically produced extracellular hydrolytic enzymes capable of yeast cell wall hydrolysis, including chitinases and mannan-degrading enzymes. In contrast, except for the A. hydrophila strain, these enzymes were not detected in anaerobic bacterial cultures, nor was the antimicrobial compound prodigiosin found in anaerobic cultures of S. marcescens. When we suspended C. albicans cells in crude extracellular enzyme preparations from K. pneumoniae and S. marcescens, we detected no negative effect on yeast viability. However, we found that these preparations enhance the toxicity of prodigiosin towards the yeast, especially in combination with mannan-degrading enzymes. Analyses of the chitin and mannan content of yeast cell walls revealed that less chitin was produced under anaerobic than aerobic conditions; however, the levels of mannan, known for its low permeability, remained the same. The latter phenomenon, as well as reduced production of the bacterial enzymes and prodigiosin, may contribute to anaerobic growth and survival of C. albicans in the presence of bacteria.

  15. Anaerobic Nitrate-Dependent Metal Bio-Oxidation

    NASA Astrophysics Data System (ADS)

    Weber, K.; Knox, T.; Achenbach, L. A.; Coates, J. D.

    2007-12-01

    Direct biological oxidation of reduced metals (Fe(II) and U(IV)) coupled to nitrate reduction at circumneutral pH under anaerobic conditions has been recognized in several environments as well as pure culture. Several phylogentically diverse mesophilic bacteria have been described as capable of anaerobic, nitrate-dependent Fe(II) oxidation (NFOx). Our recent identification of a freshwater mesophilic, lithoautotroph, Ferrutens nitratireducens strain 2002, capable of growth through NFOx presents an opportunity to further study metal bio- oxidation. Continuing physiological studies revealed that in addition to Fe(II) oxidation, strain 2002 is capable of oxidizing U(IV) (4 μM) in washed cell suspensions with nitrate serving as the electron acceptor. Pasteurized cultures exhibited abiotic oxidation of 2 μM U(IV). Under growth conditions, strain 2002 catalyzed the oxidation of 12 μM U(IV) within a two week period. Cultures amended with sodium azide, an electron transport inhibitor, demonstrated limited oxidation (7 μM) similar to pasteurized cultures, supporting the direct role of electron transport in U(IV) bio-oxidation. The oxidation of U(IV) coupled denitrification at circumneutral pH would yield enough energy to support anaerobic microbial growth (ΔG°'= -460.36 kJ/mole). It is currently unknown whether or not strain 2002 can couple this metabolism to growth. The growth of F. nitratireducens strain 2002 utilizing Fe(II) as the sole electron donor was previously demonstrated. The amount of U(IV) (~12 μM) that strain 2002 oxidized under similar autotrophic growth conditions yields 0.0019 kJ, enough energy for the generation of ATP (5.3 x 10-20 kJ ATP-1), but not enough energy for cell replication as calculated for nitrate-dependent Fe(II) oxidizing conditions (0.096 kJ) assuming a similar metabolism. In addition to F. nitratireducens strain 2002, a nitrate-dependent Fe(II) oxidizing bacterium isolated from U contaminated groundwater, Diaphorobacter sp. strain

  16. Metabolic regulation as a consequence of anaerobic 5-methylthioadenosine recycling in Rhodospirillum rubrum

    SciTech Connect

    North, Justin A.; Sriram, Jaya; Chourey, Karuna; Ecker, Christopher D.; Sharma, Ritin; Wildenthal, John A.; Hettich, Robert L.; Tabita, F. Robert

    2016-07-12

    Rhodospirillum rubrum possesses a novel oxygen-independent, aerobic methionine salvage pathway (MSP) for recycling methionine from 5-methylthioadenosine (MTA), the MTA-isoprenoid shunt. This organism can also metabolize MTA as a sulfur source under anaerobic conditions, suggesting that the MTA-isoprenoid shunt may also function anaerobically as well. In this study, deep proteomics profiling, directed metabolite analysis, and reverse transcriptase quantitative PCR (RT-qPCR) revealed metabolic changes in response to anaerobic growth on MTA versus sulfate as sole sulfur source. The abundance of protein levels associated with methionine transport, cell motility, and chemotaxis increased in the presence of MTA over that in the presence of sulfate. Purine salvage from MTA resulted primarily in hypoxanthine accumulation and a decrease in protein levels involved in GMP-to-AMP conversion to balance purine pools. Acyl coenzyme A (acyl-CoA) metabolic protein levels for lipid metabolism were lower in abundance, whereas poly-β-hydroxybutyrate synthesis and storage were increased nearly 10-fold. The known R. rubrum aerobic MSP was also shown to be upregulated, to function anaerobically, and to recycle MTA. This suggested that other organisms with gene homologues for the MTA-isoprenoid shunt may also possess a functioning anaerobic MSP. In support of our previous findings that ribulose-1,5-carboxylase/oxygenase (RubisCO) is required for an apparently purely anaerobic MSP, RubisCO transcript and protein levels both increased in abundance by over 10-fold in cells grown anaerobically on MTA over those in cells grown on sulfate, resulting in increased intracellular RubisCO activity. Lastly, these results reveal for the first time global metabolic responses as a consequence of anaerobic MTA metabolism compared to using sulfate as the sulfur source.

  17. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    SciTech Connect

    John R. Gallagher

    2001-07-31

    During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

  18. Compartment model of aerobic and anaerobic biodegradation in a municipal solid waste landfill.

    PubMed

    Kim, Sang-Yul; Tojo, Yasumasa; Matsuto, Toshihiko

    2007-12-01

    The mathematical formulations in a one-dimensional compartment model of the biodegradation of organic landfill components are described. The model is designed to switch between anaerobic and aerobic conditions, depending on the local oxygen concentration. The model also includes the effect of environmental factors, such as moisture content, pH, and temperature, on reaction rates. The model includes not only biodegradation processes for carbon compounds (acetate, CO2, CH4), but also for nitrogen compounds involved in nitrification and denitrification due to their significance in landfills. Two example runs to simulate anaerobic and aerobic waste were conducted for a single landfill unit cell by changing the organic content and diffusion coefficient.

  19. Anaerobic protocol for assessing industrial waste treatability

    SciTech Connect

    Young, J.C.; Khandaker, N.R.

    1996-11-01

    Recent promulgation of strict standards for industrial waste pretreatment has greatly increased the number of wastewaters that are candidates for anaerobic treatment. The challenge with industrial wastes is to determine the potential for anaerobic biodegradation prior to investing large amounts of time and expense in design and field investigation. Various methods have been used to assess the treatability of industrial wastewaters, but the methodology has varied significantly. In response to the need for a consistent procedure for determining the treatability of different industrial wastewaters by anaerobic processes, Young developed an anaerobic treatability screening protocol. The purpose of this paper is to describe the protocol and to report a number of case studies in which the test protocol was used to determine the feasibility of using anaerobic processes for treating specific industrial wastes. Specific examples include food processing wastes, chemical production wastes, petroleum wastes, and landfill leachate. Treatability was based on assessment of the rate and extent of biodegradation, identification of the presence of toxic substances, and dilution effects.

  20. Anaerobic growth and potential for amino acid production by nitrate respiration in Corynebacterium glutamicum.

    PubMed

    Takeno, Seiki; Ohnishi, Junko; Komatsu, Tomoha; Masaki, Tatsuya; Sen, Kikuo; Ikeda, Masato

    2007-07-01

    Oxygen limitation is a crucial problem in amino acid fermentation by Corynebacterium glutamicum. Toward this subject, our study was initiated by analysis of the oxygen-requiring properties of C. glutamicum, generally regarded as a strict aerobe. This organism formed colonies on agar plates up to relatively low oxygen concentrations (0.5% O(2)), while no visible colonies were formed in the absence of O(2). However, in the presence of nitrate (NO3-), the organism exhibited limited growth anaerobically with production of nitrite (NO2-), indicating that C. glutamicum can use nitrate as a final electron acceptor. Assays of cell extracts from aerobic and hypoxic cultures yielded comparable nitrate reductase activities, irrespective of nitrate levels. Genome analysis revealed a narK2GHJI cluster potentially relevant to nitrate reductase and transport. Disruptions of narG and narJ abolished the nitrate-dependent anaerobic growth with the loss of nitrate reductase activity. Disruption of the putative nitrate/nitrite antiporter gene narK2 did not affect the enzyme activity but impaired the anaerobic growth. These indicate that this locus is responsible for nitrate respiration. Agar piece assays using L-lysine- and L-arginine-producing strains showed that production of both amino acids occurred anaerobically by nitrate respiration, indicating the potential of C. glutamicum for anaerobic amino acid production.

  1. Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.

    PubMed

    Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A; Mortuza, M Golam; Gadd, Geoffrey Michael

    2017-03-01

    Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se(0)) under both aerobic and anaerobic conditions. The biogenic nano-Se(0) converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg(0)) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg(0) remediation, probably owing to the release of intracellular nano-Se(0) from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se(0) and Hg(0). Biosynthesis of nano-Se(0) both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg(0)-contaminated surface and subsurface soils, where the redox potential often changes dramatically.

  2. Rapid detection of a gfp-marked Enterobacter aerogenes under anaerobic conditions by aerobic fluorescence recovery.

    PubMed

    Zhang, Chong; Xing, Xin-Hui; Lou, Kai

    2005-08-15

    A gfp- and kanamycin-resistance gene-containing plasmid pUCGK was successfully constructed and transformed into Enterobacter aerogenes to develop a rapid GFP-based method for quantifying the bacterial concentration under anaerobic conditions for production of biohydrogen. Since the use of GFP as a molecular reporter is restricted by its requirement for oxygen in the development of the fluorophore, fluorescence detection for the fluorescent E. aerogenes grown anaerobically for hydrogen production was performed by developing a method of aerobic fluorescence recovery (AFR) of the anaerobically expressed GFP. By using this AFR method, rapid and non-disruptive cell quantification of E. aerogenes by fluorescence density was achieved for analyzing the hydrogen production process.

  3. Anaerobic energy-yielding reaction associated with transhydrogenation from glycerol 3-phosphate to fumarate by an Escherichia coli system.

    PubMed

    Miki, K; Lin, E C

    1975-12-01

    A particulate subcellular fraction from Escherichia coli K-12 induced in anaerobic sn-glycerol 3-phosphate (G3P) dehydrogenase and fumarate reductase can catalyze under anaerobic conditions the transfer of hydrogens from G3P to fumarate, with attendant generation of high-energy phosphate. The phsophorylation process is more sensitive than the transhydrogenation process to inhibition by the detergent Triton X-100. The same is true with respect to sensitivity to sodium azide, carbonyl cyanide m-chlorophenylhydrazone and N,N'-dicyclohexylcarbodiimide. Such a preparation derived from cells with beta-galactoside permease can accumulate thiomethyl beta-D-galactoside anaerobically, and the accumulation can be stimulated twofold by adding G3P and fumarate. Mutants lacking the membrane-associated Mg2+-dependent adenosine triphosphatase cannot grow anaerobically on glycerol with fumarate as the hydrogen acceptor, although they can grow aerobically on glycerol alone.

  4. Anaerobic energy-yielding reaction associated with transhydrogenation from glycerol 3-phosphate to fumarate by an Escherichia coli system.

    PubMed Central

    Miki, K; Lin, E C

    1975-01-01

    A particulate subcellular fraction from Escherichia coli K-12 induced in anaerobic sn-glycerol 3-phosphate (G3P) dehydrogenase and fumarate reductase can catalyze under anaerobic conditions the transfer of hydrogens from G3P to fumarate, with attendant generation of high-energy phosphate. The phsophorylation process is more sensitive than the transhydrogenation process to inhibition by the detergent Triton X-100. The same is true with respect to sensitivity to sodium azide, carbonyl cyanide m-chlorophenylhydrazone and N,N'-dicyclohexylcarbodiimide. Such a preparation derived from cells with beta-galactoside permease can accumulate thiomethyl beta-D-galactoside anaerobically, and the accumulation can be stimulated twofold by adding G3P and fumarate. Mutants lacking the membrane-associated Mg2+-dependent adenosine triphosphatase cannot grow anaerobically on glycerol with fumarate as the hydrogen acceptor, although they can grow aerobically on glycerol alone. PMID:127785

  5. Wingate Anaerobic Test peak power and anaerobic capacity classifications for men and women intercollegiate athletes.

    PubMed

    Zupan, Michael F; Arata, Alan W; Dawson, Letitia H; Wile, Alfred L; Payn, Tamara L; Hannon, Megan E

    2009-12-01

    The Wingate Anaerobic Test (WAnT) has been established as an effective tool in measuring both muscular power and anaerobic capacity in a 30-second time period; however, there are no published normative tables by which to compare WAnT performance in men and women intercollegiate athletics. The purpose of this study was to develop a classification system for anaerobic peak power and anaerobic capacity for men and women National Collegiate Athletic Association (NCAA) Division I college athletes using the WAnT. A total of 1,585 (1,374 men and 211 women) tests were conducted on athletes ranging from the ages of 18 to 25 years using the WAnT. Absolute and relative peak power and anaerobic capacity data were recorded. One-half standard deviations were used to set up a 7-tier classification system (poor to elite) for these assessments. These classifications can be used by athletes, coaches, and practitioners to evaluate anaerobic peak power and anaerobic capacity in their athletes.

  6. Changes in gene expression of Actinobacillus pleuropneumoniae in response to anaerobic stress reveal induction of central metabolism and biofilm formation.

    PubMed

    Li, Lu; Zhu, Jiawen; Yang, Kui; Xu, Zhuofei; Liu, Ziduo; Zhou, Rui

    2014-06-01

    Actinobacillus pleuropneumoniae is an important porcine respiratory pathogen causing great economic losses in the pig industry worldwide. Oxygen deprivation is a stress that A. pleuropneumoniae will encounter during both early infection and the later, persistent stage. To understand modulation of A. pleuropneumoniae gene expression in response to the stress caused by anaerobic conditions, gene expression profiles under anaerobic and aerobic conditions were compared in this study. The microarray results showed that 631 genes (27.7% of the total ORFs) were differentially expressed in anaerobic conditions. Many genes encoding proteins involved in glycolysis, carbon source uptake systems, pyruvate metabolism, fermentation and the electron respiration transport chain were up-regulated. These changes led to an increased amount of pyruvate, lactate, ethanol and acetate in the bacterial cells as confirmed by metabolite detection. Genes encoding proteins involved in cell surface structures, especially biofilm formation, peptidoglycan biosynthesis and lipopolysaccharide biosynthesis were up-regulated as well. Biofilm formation was significantly enhanced under anaerobic conditions. These results indicate that induction of central metabolism is important for basic survival of A. pleuropneumoniae after a shift to an anaerobic environment. Enhanced biofilm formation may contribute to the persistence of this pathogen in the damaged anaerobic host tissue and also in the early colonization stage. These discoveries give new insights into adaptation mechanisms of A. pleuropneumoniae in response to environmental stress.

  7. Biochemistry and physiology of anaerobic bacteria

    SciTech Connect

    2000-05-18

    We welcome you to The Power of Anaerobes. This conference serves two purposes. One is to celebrate the life of Harry D. Peck, Jr.,who was born May 18, 1927 and would have celebrated his 73rd birthday at this conference. He died November 20, 1998. The second is to gather investigators to exchange views within the realm of anaerobic microbiology, an area in which tremendous progress has been seen during recent years. It is sufficient to mention discoveries of a new form of life (the archaea), hyper or extreme thermophiles, thermophilic alkaliphiles and anaerobic fungi. With these discoveries has come a new realization about physiological and metabolic properties of microorganisms, and this in turn has demonstrated their importance for the development, maintenance and sustenance of life on Earth.

  8. Anaerobic fermentation of beef cattle manure

    NASA Astrophysics Data System (ADS)

    Hashimoto, A. G.; Chen, Y. R.; Varel, V. H.

    1981-01-01

    The conversion of livestock manure and crop residues into methane and a high protein feed ingredient by thermophilic anaerobic fermentation is summarized. The major biological and operational factors involved in methanogenesis are discussed, and a kinetic model that describes the fermentation process is presented. Substrate biodegradability, fermentation temperature, and influent substrate concentration to have significant effects on CH4 production rate. Assessment of the energy requirements for anaerobic fermentation systems showed that the major energy requirement for a thermophilic system was for maintaining the fermenter temperature. The next major energy consumption was due to the mixing of the influent slurry and fermenter liquor. An approach to optimizing anaerobic fermenter s by selecting design criteria that maximize the net energy production per unit cost is presented.

  9. Use of biochars in anaerobic digestion.

    PubMed

    Mumme, Jan; Srocke, Franziska; Heeg, Kathrin; Werner, Maja

    2014-07-01

    This study investigated the behavior of biochars from pyrolysis (pyrochar) and hydrothermal carbonization (hydrochar) in anaerobic digestion regarding their degradability and their effects on biogas production and ammonia inhibition. A batch fermentation experiment (42°C, 63 days) was conducted in 100mL syringes filled with 30 g inoculum, 2g biochar and four levels of total ammonium nitrogen (TAN). For pyrochar, no clear effect on biogas production was observed, whereas hydrochar increased the methane yield by 32%. This correlates with the hydrochar's larger fraction of anaerobically degradable carbon (10.4% of total carbon, pyrochar: 0.6%). Kinetic and microbiota analyses revealed that pyrochar can prevent mild ammonia inhibition (2.1 g TANk g(-1)). Stronger inhibitions (3.1-6.6 g TAN kg(-1)) were not mitigated, neither by pyrochar nor by hydrochar. Future research should pay attention to biochar-microbe interactions and the effects in continuously-fed anaerobic digesters.

  10. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1992-06-01

    A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least FAB making thisthe most common physiological type of anaerobic bacteria present in the deep subsurface at these two sites. INEL core samples are characterized by isolates of both FAB and OAB. No isolates of acetogenic, methanogenic, or sulfate reducing bacteria were obtained. Yakima core samples are characterized by a marked predominance of FAB in comparison to OAB. In addition, isolates of acetogenic, methanogenic, and sulfate reducing bacteria were obtained. The Yakima site has the potential for complete anaerobic mineralization of organic compounds whereas this potential appears to be lacking at INEL.

  11. Anaerobes: a new aetiology in cavitary pneumoconiosis.

    PubMed Central

    del Campo, J M; Hitado, J; Gea, G; Colmeiro, A; Lanza, A M; Muñoz, J A; Mosquera, J A

    1982-01-01

    The role of mycobacteria in the cavitation of large pneumoconiotic masses is well established. In other cases softness is attributed to an ischaemic or aseptic necrosis. Five cases are described in which cavitation of the pulmonary masses was caused by anaerobic bacteria, confirmed by the growth of such bacterial in cultures after transtracheal or transpleural puncture. Repeated cultures for mycobacteria gave negative results. Two cases were acute, having serious complications such as bronchopleural fistula, empyema, and serious respiratory insufficiency. The role of anaerobes in cavitary pneumoconiosis has not been recognised previously, probably because of the special conditions required to culture these bacteria and the infrequent use of transtracheal puncture in the diagnosis of this entity. The prevalence of anaerobes as agents capable of cavitating pneumoconiotic masses remains to be established. Images PMID:6128024

  12. Anaerobic lipid degradation through acidification and methanization.

    PubMed

    Kim, Ijung; Kim, Sang-Hyoun; Shin, Hang-Sik; Jung, Jin-Young

    2010-01-01

    In biological wastewater treatment high lipid concentration is known to inhibit microorganisms and cause active biomass flotation. To reduce lipid inhibition, a two-phase anaerobic system, consisting of an anaerobic sequencing batch reactor (ASBR) and an upflow anaerobic sludge blanket (UASB) reactor, was applied to synthetic dairy wastewater. During 153 days of operation, the two-phase system showed stable performance in lipid degradation. In the ASBR, a 13% lipid removal efficiency and 10% double bond removal efficiency were maintained. In the UASB, the chemical oxygen demand (COD), lipid and volatile fatty acid (VFA) removal efficiencies were more than 80%, 70% and 95%, respectively, up to organic loading rate 6.5 g COD/L/day. There were no operational problems such as serious scum formation or sludge washout. Protein degradation occurred prior to degradation during acidogenesis.

  13. Anaerobic oxidation of methane in hypersaline cold seep sediments.

    PubMed

    Maignien, Loïs; Parkes, R John; Cragg, Barry; Niemann, Helge; Knittel, Katrin; Coulon, Stephanie; Akhmetzhanov, Andrey; Boon, Nico

    2013-01-01

    Life in hypersaline environments is typically limited by bioenergetic constraints. Microbial activity at the thermodynamic edge, such as the anaerobic oxidation of methane (AOM) coupled to sulphate reduction (SR), is thus unlikely to thrive in these environments. In this study, carbon and sulphur cycling was investigated in the extremely hypersaline cold seep sediments of Mercator mud volcano. AOM activity was partially inhibited but still present at salinity levels of 292 g L(-1) (c. eightfold sea water concentration) with rates of 2.3 nmol cm(-3) day(-1) and was even detectable under saturated conditions. Methane and evaporite-derived sulphate comigrated in the ascending geofluids, which, in combination with a partial activity inhibition, resulted in AOM activity being spread over unusually wide depth intervals. Up to 79% of total cells in the AOM zone were identified by fluorescence in situ hybridization (FISH) as anaerobic methanotrophs of the ANME-1. Most ANME-1 cells formed monospecific chains without any attached partner. At all sites, AOM activity co-occurred with SR activity and sometimes significantly exceeded it. Possible causes of these unexpected results are discussed. This study demonstrates that in spite of a very low energy yield of AOM, microorganisms carrying this reaction can thrive in salinity up to halite saturation.

  14. Anaerobes and Gardnerella vaginalis in non-specific vaginitis.

    PubMed Central

    Hill, L V

    1985-01-01

    Clinical evidence of bacterial vaginosis was present in 25 (35%) of 72 patients attending a London venereology clinic and correlated significantly with abnormal organic acids in vaginal secretions (24/25), with Gardnerella vaginalis on culture (17/25), with complaints of vaginal malodour (15/25), and with a relative scarcity of white blood cells in vaginal secretions. Anaerobic vaginal flora were presumptively identified by gas-liquid chromatographic analysis of organic acids found in vaginal secretions. The clinical criteria used to diagnose bacterial vaginosis included the presence of at least three of the four following characteristics: (a) a vaginal pH greater than or equal to 4.5, vaginal secretions that (b) were homogeneous, (c) contained "clue" cells, and (d) released a "fishy" amine odour when mixed with 10% potassium hydroxide. Because 17 of the 25 patients with clinical bacterial vaginosis had both chromatographic bacterial vaginosis and G vaginalis, causative organisms were difficult to identify. None of the six patients who had G vaginalis but not chromatographic bacterial vaginosis had clinical bacterial vaginosis, but seven of the 10 women with chromatographic bacterial vaginosis but not G vaginalis had clinical bacterial vaginosis (p less than 0.02, chi 2 with Yates's correction). This finding supports the recent suggestions that anaerobes are important in the production of clinical signs of bacterial vaginosis. PMID:3872256

  15. Improving Project Outcomes and Growing the Anaerobic Digestion Industy Report

    EPA Pesticide Factsheets

    Anaerobic digestion ombudsmen assist with project development, ensure the long-term sustainability of projects, and help advance the industry. This report explores the benefits of anaerobic digestion ombudsmen and provides guidance for implementing them.

  16. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  17. Hydrogen production from the dissolution of nano zero valent iron and its effect on anaerobic digestion.

    PubMed

    Huang, Yu-Xi; Guo, Jialiang; Zhang, Chunyang; Hu, Zhiqiang

    2016-01-01

    Nano zero valent iron (NZVI) has shown inhibition on methanogenesis in anaerobic digestion due to its reductive decomposition of cell membrane. The inhibition was accompanied by the accumulation of hydrogen gas due to rapid NZVI dissolution. It is not clear whether and how rapid hydrogen release from NZVI dissolution directly affects anaerobic digestion. In this study, the hydrogen release kinetics from NZVI (average size = 55 ± 11 nm) dissolution in deionized water under anaerobic conditions was first evaluated. The first-order NZVI dissolution rate constant was 2.62 ± 0.26 h(-1) with its half-life of 0.26 ± 0.03 h. Two sets of anaerobic digestion experiments (i.e., in the presence of glucose or without any substrate but at different anaerobic sludge concentrations) were performed to study the impact of H2 release from rapid NZVI dissolution, in which H2 was generated in a separate water bottle containing NZVI (i.e., ex situ H2 or externally supplied from NZVI dissolution) before hydrogen gas was introduced to anaerobic digestion. The results showed that the H2 partial pressure in the headspace of the digestion bottle reached as high as 0.27 atm due to rapid NZVI dissolution, resulting in temporary inhibition of methane production. Nevertheless, the 5-d cumulative methane volume in the group with ex situ H2 production due to NZVI dissolution was actually higher than that of control, suggesting NZVI inhibition on methanogenesis is solely due to the reductive decomposition of cell membrane after direct contact with NZVI.

  18. Transposon mutagenesis identified chromosomal and plasmid genes essential for adaptation of the marine bacterium Dinoroseobacter shibae to anaerobic conditions.

    PubMed

    Ebert, Matthias; Laaß, Sebastian; Burghartz, Melanie; Petersen, Jörn; Koßmehl, Sebastian; Wöhlbrand, Lars; Rabus, Ralf; Wittmann, Christoph; Tielen, Petra; Jahn, Dieter

    2013-10-01

    Anaerobic growth and survival are integral parts of the life cycle of many marine bacteria. To identify genes essential for the anoxic life of Dinoroseobacter shibae, a transposon library was screened for strains impaired in anaerobic denitrifying growth. Transposon insertions in 35 chromosomal and 18 plasmid genes were detected. The essential contribution of plasmid genes to anaerobic growth was confirmed with plasmid-cured D. shibae strains. A combined transcriptome and proteome approach identified oxygen tension-regulated genes. Transposon insertion sites of a total of 1,527 mutants without an anaerobic growth phenotype were determined to identify anaerobically induced but not essential genes. A surprisingly small overlap of only three genes (napA, phaA, and the Na(+)/Pi antiporter gene Dshi_0543) between anaerobically essential and induced genes was found. Interestingly, transposon mutations in genes involved in dissimilatory and assimilatory nitrate reduction (napA, nasA) and corresponding cofactor biosynthesis (genomic moaB, moeB, and dsbC and plasmid-carried dsbD and ccmH) were found to cause anaerobic growth defects. In contrast, mutation of anaerobically induced genes encoding proteins required for the later denitrification steps (nirS, nirJ, nosD), dimethyl sulfoxide reduction (dmsA1), and fermentation (pdhB1, arcA, aceE, pta, acs) did not result in decreased anaerobic growth under the conditions tested. Additional essential components (ferredoxin, cccA) of the anaerobic electron transfer chain and central metabolism (pdhB) were identified. Another surprise was the importance of sodium gradient-dependent membrane processes and genomic rearrangements via viruses, transposons, and insertion sequence elements for anaerobic growth. These processes and the observed contributions of cell envelope restructuring (lysM, mipA, fadK), C4-dicarboxylate transport (dctM1, dctM3), and protease functions to anaerobic growth require further investigation to unravel the

  19. [Sulfa-drug wastewater treatment with anaerobic/aerobic process].

    PubMed

    Wu, L; Zhang, H; Zhu, H; Zhang, Z; Zhuang, Y; Dai, S

    2001-09-01

    Sulfa drug wastewater was treated with anaerobic/aerobic process. The removal ratios of TOC reached about 50% in anaerobic phase and about 70% in aerobic phase respectively, while volume loading rate of TOC was about 1.2 kg/(m3.d) in anaerobic phase and about 0.6 kg/(m3.d) in aerobic phase. Removal of TOC in anaerobic phase was attributed to the reduction of sulfate.

  20. Robust regulation of anaerobic digestion processes.

    PubMed

    Mailleret, L; Bernard, O; Steyer, J P

    2003-01-01

    This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.

  1. Understanding how commensal obligate anaerobic bacteria regulate immune functions in the large intestine.

    PubMed

    Maier, Eva; Anderson, Rachel C; Roy, Nicole C

    2014-12-24

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases.

  2. Understanding How Commensal Obligate Anaerobic Bacteria Regulate Immune Functions in the Large Intestine

    PubMed Central

    Maier, Eva; Anderson, Rachel C.; Roy, Nicole C.

    2014-01-01

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases. PMID:25545102

  3. Microbial nitrate-dependent cyclohexane degradation coupled with anaerobic ammonium oxidation.

    PubMed

    Musat, Florin; Wilkes, Heinz; Behrends, Astrid; Woebken, Dagmar; Widdel, Friedrich

    2010-10-01

    An anaerobic nitrate-reducing enrichment culture was established with a cyclic saturated petroleum hydrocarbon, cyclohexane, the fate of which in anoxic environments has been scarcely investigated. GC-MS showed cyclohexylsuccinate as a metabolite, in accordance with an anaerobic enzymatic activation of cyclohexane by carbon-carbon addition to fumarate. Furthermore, long-chain cyclohexyl-substituted cell fatty acids apparently derived from cyclohexane were detected. Nitrate reduction was not only associated with cyclohexane utilization but also with striking depletion of added ammonium ions. Significantly more ammonium was consumed than could be accounted for by assimilation. This indicated the occurrence of anaerobic ammonium oxidation (anammox) with nitrite from cyclohexane-dependent nitrate reduction. Indeed, nitrite depletion was stimulated upon further addition of ammonium. Analysis of 16S rRNA genes and subsequent cell hybridization with specific probes showed that approximately 75% of the bacterial cells affiliated with the Geobacteraceae and approximately 18% with Candidatus 'Brocadia anammoxidans' (member of the Planctomycetales), an anaerobic ammonium oxidizer. These results and additional quantitative growth experiments indicated that the member of the Geobacteraceae reduced nitrate with cyclohexane to nitrite and some ammonium; the latter two and ammonium added to the medium were scavenged by anammox bacteria to yield dinitrogen. A model was established to quantify the partition of each microorganism in the overall process. Such hydrocarbon oxidation by an alleged 'denitrification' ('pseudo-denitrification'), which in reality is a dissimilatory loop through anammox, can in principle also occur in other microbial systems with nitrate-dependent hydrocarbon attenuation.

  4. Highly divergent mitochondrion-related organelles in anaerobic parasitic protozoa.

    PubMed

    Makiuchi, Takashi; Nozaki, Tomoyoshi

    2014-05-01

    The mitochondria have arisen as a consequence of endosymbiosis of an ancestral α-proteobacterium with a methane-producing archae. The main function of the canonical aerobic mitochondria include ATP generation via oxidative phosphorylation, heme and phospholipid synthesis, calcium homeostasis, programmed cell death, and the formation of iron-sulfur clusters. Under oxygen-restricted conditions, the mitochondrion has often undergone remarkable reductive alterations of its content and function, leading to the generation of mitochondrion-related organelles (MROs), such as mitosomes, hydrogenosomes, and mithochondrion-like organelles, which are found in a wide range of anaerobic/microaerophilic eukaryotes that include several medically important parasitic protists such as Entamoeba histolytica, Giardia intestinalis, Trichomonas vaginalis, Cryptosporidium parvum, Blastocystis hominis, and Encephalitozoon cuniculi, as well as free-living protists such as Sawyeria marylandensis, Neocallimastix patriciarum, and Mastigamoeba balamuthi. The transformation from canonical aerobic mitochondria to MROs apparently have occurred in independent lineages, and resulted in the diversity of their components and functions. Due to medical and veterinary importance of the MRO-possessing human- and animal-pathogenic protozoa, their genomic, transcriptomic, proteomic, and biochemical evidence has been accumulated. Detailed analyses of the constituents and functions of the MROs in such anaerobic pathogenic protozoa, which reside oxygen-deprived or oxygen-poor environments such as the mammalian intestine and the genital organs, should illuminate the current evolutionary status of the MROs in these organisms, and give insight to environmental constraints that drive the evolution of eukaryotes and their organelles. In this review, we summarize and discuss the diverse metabolic functions and protein transport systems of the MROs from anaerobic parasitic protozoa.

  5. Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Carnegie, John W., Ed.

    This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

  6. The Influence of Hydration on Anaerobic Performance: A Review

    ERIC Educational Resources Information Center

    Kraft, Justin A.; Green, James M.; Bishop, Phillip A.; Richardson, Mark T.; Neggers, Yasmin H.; Leeper, James D.

    2012-01-01

    This review examines the influence of dehydration on muscular strength and endurance and on single and repeated anaerobic sprint bouts. Describing hydration effects on anaerobic performance is difficult because various exercise modes are dominated by anaerobic energy pathways, but still contain inherent physiological differences. The critical…

  7. Waste to Energy Potential - A High Concentration Anaerobic Bioreactor

    DTIC Science & Technology

    2012-05-23

    output • Uses the organic portion of solid waste (such as food waste , paper products, and agricultural waste ) to fuel an anaerobic digestion ...Sustainability Symposium & Exhibition Anaerobic Digestion • What does it do? • Offers sustainability by addressing renewable energy, waste ... Waste to Energy Potential – A High Concentration Anaerobic Bioreactor Presenter: Scott Murphy & Rebecca Robbennolt ARCADIS/Malcolm Pirnie Date

  8. The multidrug efflux pump MdtEF protects against nitrosative damage during the anaerobic respiration in Escherichia coli.

    PubMed

    Zhang, Yiliang; Xiao, Minfeng; Horiyama, Tsukasa; Zhang, Yinfeng; Li, Xuechen; Nishino, Kunihiko; Yan, Aixin

    2011-07-29

    Drug efflux represents an important protection mechanism in bacteria to withstand antibiotics and environmental toxic substances. Efflux genes constitute 6-18% of all transporters in bacterial genomes, yet the expression and functions of only a handful of them have been studied. Among the 20 efflux genes encoded in the Escherichia coli K-12 genome, only the AcrAB-TolC system is constitutively expressed. The expression, activities, and physiological functions of the remaining efflux genes are poorly understood. In this study we identified a dramatic up-regulation of an additional efflux pump, MdtEF, under the anaerobic growth condition of E. coli, which is independent of antibiotic exposure. We found that expression of MdtEF is up-regulated more than 20-fold under anaerobic conditions by the global transcription factor ArcA, resulting in increased efflux activity and enhanced drug tolerance in anaerobically grown E. coli. Cells lacking mdtEF display a significantly decreased survival rate under the condition of anaerobic respiration of nitrate. Deletion of the genes responsible for the biosynthesis of indole, tnaAB, or replacing nitrate with fumarate as the terminal electron acceptor during the anaerobic respiration restores the decreased survival of ΔmdtEF cells. Moreover, ΔmdtEF cells are susceptible to indole nitrosative derivatives, a class of toxic byproducts formed and accumulated within E. coli when the bacterium respires nitrate under anaerobic conditions. Taken together, we conclude that the multidrug efflux pump MdtEF is up-regulated during the anaerobic physiology of E. coli to protect the bacterium from nitrosative damage through expelling the nitrosyl indole derivatives out of the cells.

  9. Identification of genes specifically required for the anaerobic metabolism of benzene in Geobacter metallireducens

    PubMed Central

    Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh K.; Smith, Jessica A.; Bain, Timothy S.; Lovley, Derek R.

    2014-01-01

    Although the biochemical pathways for the anaerobic degradation of many of the hydrocarbon constituents in petroleum reservoirs have been elucidated, the mechanisms for anaerobic activation of benzene, a very stable molecule, are not known. Previous studies have demonstrated that Geobacter metallireducens can anaerobically oxidize benzene to carbon dioxide with Fe(III) as the sole electron acceptor and that phenol is an intermediate in benzene oxidation. In an attempt to identify enzymes that might be involved in the conversion of benzene to phenol, whole-genome gene transcript abundance was compared in cells metabolizing benzene and cells metabolizing phenol. Eleven genes had significantly higher transcript abundance in benzene-metabolizing cells. Five of these genes had annotations suggesting that they did not encode proteins that could be involved in benzene metabolism and were not further studied. Strains were constructed in which one of the remaining six genes was deleted. The strain in which the monocistronic gene Gmet 0232 was deleted metabolized phenol, but not benzene. Transcript abundance of the adjacent monocistronic gene, Gmet 0231, predicted to encode a zinc-containing oxidoreductase, was elevated in cells metabolizing benzene, although not at a statistically significant level. However, deleting Gmet 0231 also yielded a strain that could metabolize phenol, but not benzene. Although homologs of Gmet 0231 and Gmet 0232 are found in microorganisms not known to anaerobically metabolize benzene, the adjacent localization of these genes is unique to G. metallireducens. The discovery of genes that are specifically required for the metabolism of benzene, but not phenol in G. metallireducens is an important step in potentially identifying the mechanisms for anaerobic benzene activation. PMID:24904558

  10. Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

    SciTech Connect

    Mosey, F.E.

    1996-01-01

    This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

  11. Anaerobic Production of Thiobacillus denitrificans for the Enzyme Rhodanese

    PubMed Central

    Sargeant, K.; Buck, P. W.; Ford, J. W. S.; Yeo, R. G.

    1966-01-01

    A method for the anaerobic growth of Thiobacillus denitrificans in a 140-liter (total capacity) stainless-steel culture vessel is described. As a result of controlling the pH value of cultures, and of ensuring that certain essential nutrients were in excess, cell yields approaching 700 mg (dry weight) per liter were obtained. These were over threefold higher than the best yields hitherto reported. The average rhodanese content of the cells from four cultures was 176,000 units per gram (dry weight). Adenosine-5′-phosphosulfate reductase (average content, 238 units per gram dry weight) and adenylate kinase (average content, 15,300 units per gram, dry weight) were also present. PMID:16349709

  12. Wingate Anaerobic Test Peak Power and Anaerobic Capacity Classification for Men and Women Intercollegiate Athletes

    DTIC Science & Technology

    2009-12-01

    including football, sprinting, soccer, baseball, lacrosse, and gymnastics - use anaerobic metabolism extensively during competition. This study...1 . 3 62j + 7.7 167.1 + 7 .9 Tennis, track, soccer, and gymnastics urements allow a coach to observe individual improvements; however, it is...require short bursts of peak power and a high anaerobic capacity during competition to include lacrosse, gymnastics , sprint cycling, football, baseball

  13. Studies on upflow anaerobic filter

    NASA Astrophysics Data System (ADS)

    Varandani, Nanik Sobhraj

    The thesis presents a critical review of the available literature on the various studies carried out on various aspects of Upflow Anaerobic Filter (UAF) throughout the world. Young and McCarty (1969) did the pioneering work in developing UAF in 1969, since then several studies have been carried out by different researchers using different substrates under different operating conditions and variety of supporting media. However, the most significant modification of the original reactor developed by Young and McCarty (1968), has been the development and use of high porosity media. The use of high porosity media, in fact, has changed the character of the reactor, from basically a fixed film reactor to a fixed film reactor in which the contribution by the suspended bio-solids, entrapped in the numerous media pores, in the substrate removal is quite significant that is to say that the reactor no longer remains a biological reactor which can be modeled and designed on the basis of biofilm kinetics only. The thesis presents an attempt to validate the developed mathematical model(s) by using the laboratory scale reactor performance data and the calculated values of reaction kinetic and bio-kinetic constants. To simplify the verification process, computer programmes have been prepared using the "EXCELL" software and C language. The results of the "EXCELL" computer program runs are tabulated at table no. 7.1 to 7.5. The verification of various mathematical models indicate that the model III B, i.e. Non ideal plug flow model assumed to consist of Complete Mix Reactors in series based on reaction kinetics, gives results with least deviation from the real situation. An interesting observation being that the model offers least deviation or nearly satisfies the real situation for a particular COD removal efficiency, for a particular OLR, eg. the least deviations are obtained at COD removal efficiency of 89% for OLR 2, 81.5% for OLR 4, 78.5% for OLR 6 . However, the use of the

  14. Microbial communities mediating algal detritus turnover under anaerobic conditions

    PubMed Central

    Morrison, Jessica M.; Murphy, Chelsea L.; Baker, Kristina; Zamor, Richard M.; Nikolai, Steve J.; Wilder, Shawn; Elshahed, Mostafa S.

    2017-01-01

    Background Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic ecosystems, providing a significant autochthonous carbon input to the deeper anoxic layers in stratified water bodies. In addition, various algal species have been touted as promising candidates for anaerobic biogas production from biomass. Surprisingly, in spite of its ecological and economic relevance, the microbial community involved in algal detritus turnover under anaerobic conditions remains largely unexplored. Results Here, we characterized the microbial communities mediating the degradation of Chlorella vulgaris (Chlorophyta), Chara sp. strain IWP1 (Charophyceae), and kelp Ascophyllum nodosum (phylum Phaeophyceae), using sediments from an anaerobic spring (Zodlteone spring, OK; ZDT), sludge from a secondary digester in a local wastewater treatment plant (Stillwater, OK; WWT), and deeper anoxic layers from a seasonally stratified lake (Grand Lake O’ the Cherokees, OK; GL) as inoculum sources. Within all enrichments, the majority of algal biomass was metabolized within 13–16 weeks, and the process was accompanied by an increase in cell numbers and a decrease in community diversity. Community surveys based on the V4 region of the 16S rRNA gene identified different lineages belonging to the phyla Bacteroidetes, Proteobacteria (alpha, delta, gamma, and epsilon classes), Spirochaetes, and Firmicutes that were selectively abundant under various substrate and inoculum conditions. Within all kelp enrichments, the microbial communities structures at the conclusion of the experiment were highly similar regardless of the enrichment source, and were dominated by the genus Clostridium, or family Veillonellaceae within the Firmicutes. In all other enrichments the final microbial community was dependent on the inoculum source, rather than the type of algae utilized as substrate. Lineages enriched

  15. Early Microbial Evolution: The Age of Anaerobes.

    PubMed

    Martin, William F; Sousa, Filipa L

    2015-12-18

    In this article, the term "early microbial evolution" refers to the phase of biological history from the emergence of life to the diversification of the first microbial lineages. In the modern era (since we knew about archaea), three debates have emerged on the subject that deserve discussion: (1) thermophilic origins versus mesophilic origins, (2) autotrophic origins versus heterotrophic origins, and (3) how do eukaryotes figure into early evolution. Here, we revisit those debates from the standpoint of newer data. We also consider the perhaps more pressing issue that molecular phylogenies need to recover anaerobic lineages at the base of prokaryotic trees, because O2 is a product of biological evolution; hence, the first microbes had to be anaerobes. If molecular phylogenies do not recover anaerobes basal, something is wrong. Among the anaerobes, hydrogen-dependent autotrophs--acetogens and methanogens--look like good candidates for the ancestral state of physiology in the bacteria and archaea, respectively. New trees tend to indicate that eukaryote cytosolic ribosomes branch within their archaeal homologs, not as sisters to them and, furthermore tend to root archaea within the methanogens. These are major changes in the tree of life, and open up new avenues of thought. Geochemical methane synthesis occurs as a spontaneous, abiotic exergonic reaction at hydrothermal vents. The overall similarity between that reaction and biological methanogenesis fits well with the concept of a methanogenic root for archaea and an autotrophic origin of microbial physiology.

  16. Hemicellulases from anaerobic thermophiles. Progress report

    SciTech Connect

    Wiegel, J.

    1994-05-01

    The longterm goal of this research effort is to obtain an anaerobic thermophilic bacterium that efficiently converts various hemicellulose-containing biomass to ethanol over a broad pH range. The strategy is to modify the outfit and regulation of the rate-limiting xylanases, glycosidases and xylan esterases in the ethanologenic, anaerobic thermophile Thermoanaerobacter ethanolicus, which grows between pH 4.5 and 9.5. Although it utilizes xylans, the xylanase, acetyl(xylan) esterase and O-methylglucuronidase activities in T. ethanolicus are barely measurable and regarded as the rate limiting steps in its xylan utilization. Thus, and also due to the presently limited knowledge of hemicellulases in anaerobic thermophiles, we characterize the hemicellulolytic enzymes from this and other anaerobic thermophiles as enzyme donors. Beside the active xylosidase/arabinosidase from T. ethanolicus, exhibiting the two different activities, we characterized 2 xylosidases, two acetyl(xylan) esterases, and an O-methylglucuronidase from Thermoanaerobacterium spec. We will continue with the characterization of xylanases from novel isolated slightly acidophilic, neutrophilic and slightly alkalophilic thermophiles. We have cloned, subcloned and partially sequenced the 165,000 Da (2 x 85,000) xylosidase/arabinosidase from T. ethanolicus and started with the cloning of the esterases from Thermoanaerobacterium spec. Consequently, we will develop a shuttle vector and continue to apply electroporation of autoplasts as a method for cloning into T. ethanolicus.

  17. The anaerobic digestion of organic solid wastes

    SciTech Connect

    Hartung, H.A.

    1996-09-01

    Anaerobic digestion offers many advantages in the processing of organic solid wastes, using a closed system to convert the waste to combustible gas and a stabilized organic residue.Odors are contained while digestion removes their source and gas is collected for energy recovery as heat or electricity. The stabilized residue is less than the starting waste by the mass of gas produced, and it can be disposed of by land application, land filling, incineration or composting. The stimulation of digesters and the phenomenon of co-digestion are two ways the performance of anaerobic digesters can be enhanced. Data from farm digesters and municipal wastewater treatment plants illustrate the present venue of the process; laboratory studies of the anaerobic digestion of a variety of solid wastes show that the process can be applied to these materials as well. About two thirds of municipal solid waste is shown to be amenable to anaerobic digestion in a substrate from an active municipal sewage plant digester.

  18. Circadian rhythm in anaerobic power and capacity.

    PubMed

    Hill, D W; Smith, J C

    1991-03-01

    Anaerobic power and capacity were measured in nine college-age men at four different times of day: 03.00 h, 09.00 h, 15.00 h, and 21.00 h. Modified Wingate tests were performed against a common resistance of 5.5 kg (0.074 +/- 0.004 kg per kg body mass). Peak power was defined as the highest power output during a 5-s period in the test, and anaerobic capacity was defined as the total external work during the 30-s test. Peak power tended to differ across testing times (F = 2.50, p = .10), with the mean at 21.00 h about 8% higher (p less than .05) than at 03.00 h. Anaerobic capacity differed across the times of day (F = 9.58, p less than .01), with the means at 15.00 h and 21.00 h about 5% higher (p less than .05) than at 03.00 h and 09.00 h. These results suggest that there are circadian rhythms in anaerobic power and capacity.

  19. Gender differences in anaerobic power tests.

    PubMed

    Mayhew, J L; Salm, P C

    1990-01-01

    The purpose of this study was to determine if the differences in anaerobic power between males and females could be accounted for by differences in body composition, strength, and neuromuscular function. A total of 82 untrained men and 99 women took part in the study. Body composition, somatotype, isometric strength, neuromuscular function were measured, and four anaerobic power tests performed. The men were significantly different from the women on all strength, power, and neuromuscular measurements except reaction time and on all anthropometric and somatotype dimensions except ectomorphy. Strength and anthropometric dimensions were similarly related to anaerobic power values within each sex. Relative fat (%fat) exerted different degrees of influence on sprint and jump performances in each sex. Removing the influence of anthropometric, strength, and neuromuscular differences by analysis of covariance reduced, but did not remove, the significant differences between the sexes. Therefore, factors other than lean body mass, leg strength, and neuromuscular function may be operating in short-term, explosive power performances to account for the differences between the sexes. The task-specific nature of anaerobic power tests and the relatively large influence of anthropometric factors on power production were confirmed.

  20. Anaerobic biodegradation of surrogate naphthenic acids.

    PubMed

    Clothier, Lindsay N; Gieg, Lisa M

    2016-03-01

    Surface bitumen extraction from the Alberta's oil sands region generates large settling basins known as tailings ponds. The oil sands process-affected water (OSPW) stored in these ponds contain solid and residual bitumen-associated compounds including naphthenic acids (NAs) that can potentially be biodedgraded by indigenous tailings microorganisms. While the biodegradation of some NAs is known to occur under aerobic conditions, little is understood about anaerobic NA biodegradation even though tailings ponds are mainly anoxic. Here, we investigated the potential for anaerobic NA biodegradation by indigenous tailings microorganisms. Enrichment cultures were established from anoxic tailings that were amended with 5 single-ringed surrogate NAs or acid-extractable organics (AEO) from OSPW and incubated under nitrate-, sulfate-, iron-reducing, and methanogenic conditions. Surrogate NA depletion was observed under all anaerobic conditions tested to varying extents, correlating to losses in the respective electron acceptor (sulfate or nitrate) or the production of predicted products (Fe(II) or methane). Tailings-containing cultures incubated under the different electron-accepting conditions resulted in the enrichment and putative identification of microbial community members that may function in metabolizing surrogate NAs under the various anoxic conditions. In addition, more complex NAs (in the form of AEO) was observed to drive sulfate and iron reduction relative to controls. Overall, this study has shown that simple surrogate NAs can be biodegraded under a variety of anoxic conditions, a key first step in understanding the potential anaerobic metabolism of NAs in oil sands tailings ponds and other industrial wastewaters.

  1. Anaerobic fitness tests: what are we measuring?

    PubMed

    Van Praagh, Emmanuel

    2007-01-01

    Anaerobic fitness, during growth and development, has not received the same attention from researchers as aerobic fitness. This is surprising given the level of anaerobic energy used daily during childhood and adolescence. During physical activity and sport, the child is spontaneously more attracted to short-burst movements than to long-term activities. It is, however, well known that in anaerobic activities such as sprint cycling, sprint running or sprint swimming, the child's performance is distinctly poorer than that of the adult. This partly reflects the child's lesser ability to generate mechanical energy from chemical energy sources during short-term high-intensity work or exercise. Direct measurements of the rate or capacity of anaerobic pathways for energy turnover presents several ethical and methodological difficulties. Therefore, rather than measure energy supply, pediatric exercise scientists have concentrated on measuring short-term power output by means of standardized protocol tests such as short-term cycling power tests, running tests or vertical jump tests. There is, however, no perfect test and, therefore, it is important to acknowledge the benefits and limitations of each testing method. Mass-related short-term power output was shown to increase dramatically during growth and development, whereas the corresponding increase in peak blood lactate was considerably lower. This suggests that the observed difference between children and adolescents during short-term power output testing may be related to neuromuscular factors, hormonal factors and improved motor coordination.

  2. Anaerobic Toxicity of Cationic Silver Nanoparticles

    EPA Science Inventory

    The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged p...

  3. Anaerobic Digestion in a Flooded Densified Leachbed

    NASA Technical Reports Server (NTRS)

    Chynoweth, David P.; Teixeira, Arthur A.; Owens, John M.; Haley, Patrick J.

    2009-01-01

    A document discusses the adaptation of a patented biomass-digesting process, denoted sequential batch anaerobic composting (SEBAC), to recycling of wastes aboard a spacecraft. In SEBAC, high-solids-content biomass wastes are converted into methane, carbon dioxide, and compost.

  4. Anaerobic threshold measurements of elite oarsmen.

    PubMed

    Mickelson, T C; Hagerman, F C

    1982-01-01

    Anaerobic threshold (AT) and Vo2max were determined by automated analysis for 25 members of the 1980 U.S. Olympic Rowing Team during a progressive rowing ergometer exercise to exhaustion. Heart rates and power outputs were also measured to gauge severity of the exercise and to compare with metabolic data. Power increments of 27 W each min were achieved by progressively increasing the brake weight resistance on the ergometer while maintaining a stroke rate of 28-32 strokes/min and spinning the ergometer flywheel at 550 rpm. Anaerobic threshold measurements were determined by observing the onset of the non-linear relationship between Vo2 and VE-Vco2; plots of delta FEO2 and FECO2 were also utilized to confirm recorded AT's. A mean AT of 83% of Vo2max attests to the high aerobic capacity of oarsmen and supports previous research conducted with these subjects. Power output data indicated that 72% of total power is generated at AT; this substantiates previous energy cost data recorded during simulated rowing during which work was 70% aerobic and 30% anaerobic. High levels of anaerobic thresholds among oarsmen are attributed to the specific nature of training regimens that increase oxidative capacity of muscle fibers and significantly improve the cardiorespiratory transport system. Measurement of heart rate at AT has provided coaches and athletes an objective method of determining the intensity of training sessions.

  5. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

  6. Recovery of anaerobic, facultative, and aerobic bacteria from clinical specimens in three anaerobic transport systems.

    PubMed

    Helstad, A G; Kimball, J L; Maki, D G

    1977-06-01

    With aspirated specimens from clinical infections, we evaluated the recovery of anaerobic, aerobic, and facultative bacteria in three widely used transport systems: (i) aspirated fluid in a gassed-out tube (FGT), (ii) swab in modified Cary and Blair transport medium (SCB), and (iii) swab in a gassed-out tube (SGT). Transport tubes were held at 25 degrees C and semiquantitatively sampled at 0, 2, 24, and 48 h. Twenty-five clinical specimens yielded 75 anaerobic strains and 43 isolates of facultative and 3 of aerobic bacteria. Only one anaerobic isolate was not recovered in the first 24 h, and then, only in the SGT. At 48 h, 73 anaerobic strains (97%) were recovered in the FGT, 69 (92%) in the SCB, and 64 (85%) in the SGT. Two problems hindered the recovery of anaerobes in the SCB and SGT systems: first die-off of organisms, as evidenced by a decrease in colony-forming units of 20 strains (27%) in the SCB and 25 strains (33%) in the SGT, as compared with 7 strains (9%) in the FGT, over 48 h; and second, overgrowth of facultative bacteria, more frequent with SCB and SGT. The FGT method was clearly superior at 48 h to the SCB and SGT systems in this study and is recommended as the preferred method for transporting specimens for anaerobic culture.

  7. Activation of cholera toxin production by anaerobic respiration of trimethylamine N-oxide in Vibrio cholerae.

    PubMed

    Lee, Kang-Mu; Park, Yongjin; Bari, Wasimul; Yoon, Mi Young; Go, Junhyeok; Kim, Sang Cheol; Lee, Hyung-Il; Yoon, Sang Sun

    2012-11-16

    Vibrio cholerae is a gram-negative bacterium that causes cholera. Although the pathogenesis caused by this deadly pathogen takes place in the intestine, commonly thought to be anaerobic, anaerobiosis-induced virulence regulations are not fully elucidated. Anerobic growth of the V. cholerae strain, N16961, was promoted when trimethylamine N-oxide (TMAO) was used as an alternative electron acceptor. Strikingly, cholera toxin (CT) production was markedly induced during anaerobic TMAO respiration. N16961 mutants unable to metabolize TMAO were incapable of producing CT, suggesting a mechanistic link between anaerobic TMAO respiration and CT production. TMAO reductase is transported to the periplasm via the twin arginine transport (TAT) system. A similar defect in both anaerobic TMAO respiration and CT production was also observed in a N16961 TAT mutant. In contrast, the abilities to grow on TMAO and to produce CT were not affected in a mutant of the general secretion pathway. This suggests that V. cholerae may utilize the TAT system to secrete CT during TMAO respiration. During anaerobic growth with TMAO, N16961 cells exhibit green fluorescence when stained with 2',7'-dichlorofluorescein diacetate, a specific dye for reactive oxygen species (ROS). Furthermore, CT production was decreased in the presence of an ROS scavenger suggesting a positive role of ROS in regulating CT production. When TMAO was co-administered to infant mice infected with N16961, the mice exhibited more severe pathogenic symptoms. Together, our results reveal a novel anaerobic growth condition that stimulates V. cholerae to produce its major virulence factor.

  8. Suppression of Eis and expression of Wag31 and GroES in Mycobacterium tuberculosis cytosol under anaerobic culture conditions.

    PubMed

    Maurya, Vineet K; Singh, Kavita; Sinha, Sudhir

    2014-08-01

    A major impediment in chemotherapy of Tuberculosis (TB) is the persistence of M. tuberculosis in a latent or dormant state, possibly perpetuated by paucity of oxygen within the lung granuloma. Proteome analysis of the anaerobically persisting microbe could therefore provide novel targets for drugs against latent TB infection (LTBI). An Indian clinical isolate of M. tuberculosis was cultured under aerobic and anaerobic conditions following Wayne's hypoxia model and its cytosolic proteins were resolved by two-dimensional gel electrophoresis (2DE). Peptide mass fingerprinting of 32 differentially expressed spots using MALDI TOF-TOF MS-MS resulted in identification of 23 proteins. Under the anaerobic culture conditions, expression of 12 of these proteins was highly suppressed (>2 fold reduction in spot volumes), with 4 of them (GrpE, CanB, MoxR1 and Eis) appearing as completely suppressed since corresponding spots were not detectable in the anaerobic sample. On the other hand, 4 proteins were highly expressed, with two of them (Wag31 and GroES) being uniquely expressed under anaerobic conditions. Suppression of Eis could make the anaerobically persisting bacilli susceptible to the aminoglycoside antibiotics which are known to be acetylated and inactivated by Eis. Although all 4 overexpressed proteins can be considered as putative drug targets for LTBI, Wag31 appears particularly interesting in view of its role in the cell wall biogenesis.

  9. Laboratory Study of Chemical Speciation of Mercury in Lake Sediment and Water under Aerobic and Anaerobic Conditions

    PubMed Central

    Regnell, Olof; Tunlid, Anders

    1991-01-01

    Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems than in the aerobic systems. The composition and total concentration of fatty acids originating from bacterial phospholipids, as well as the concentration of vitamin B12, including related cobalamins, were similar in sediments from the anaerobic and aerobic systems. Bacterial cell numbers were, on average, 3.6 times higher in the anaerobic water columns than in the aerobic ones. Volatilization of 203Hg occurred in all systems except in an autoclaved control and was of similar magnitudes in the anaerobic and aerobic systems. Incorporation of 203Hg into the sediment was significantly faster in the aerobic systems than in the anaerobic systems. These results suggest that episodes of anoxia in bottom waters and sediment cause an increase in net mercury methylation and, hence, an increase in bioavailable mercury. PMID:16348444

  10. Anaerobic Bacterial Fermentation Products Increase Tuberculosis Risk in Antiretroviral-Drug-Treated HIV Patients.

    PubMed

    Segal, Leopoldo N; Clemente, Jose C; Li, Yonghua; Ruan, Chunhai; Cao, Jane; Danckers, Mauricio; Morris, Alison; Tapyrik, Sarah; Wu, Benjamin G; Diaz, Philip; Calligaro, Gregory; Dawson, Rodney; van Zyl-Smit, Richard N; Dheda, Keertan; Rom, William N; Weiden, Michael D

    2017-03-22

    Despite the immune-reconstitution with antiretroviral therapy (ART), HIV-infected individuals remain highly susceptible to tuberculosis (TB) and have an enrichment of oral anaerobes in the lung. Products of bacterial anaerobic metabolism, like butyrate and other short-chain fatty acids (SCFAs), induce regulatory T cells (Tregs). We tested whether SCFAs contribute to poor TB control in a longitudinal cohort of ART-treated HIV-infected South Africans. Increase in serum SCFAs was associated with increased TB susceptibility. SCFAs inhibited IFN-γ and IL-17A production in peripheral blood mononuclear cells from HIV-infected ART-treated individuals in response to M. tuberculosis antigen stimulation. Pulmonary SCFAs correlated with increased oral anaerobes, such as Prevotella in the lung, and with M. tuberculosis antigen-induced Tregs. Metabolites from anaerobic bacterial fermentation may, therefore, increase TB susceptibility by suppressing IFN-γ and IL-17A production during the cellular immune response to M. tuberculosis.

  11. Identification of the regulatory sequence of anaerobically expressed locus aeg-46.5.

    PubMed Central

    Choe, M; Reznikoff, W S

    1993-01-01

    A newly identified anaerobically expressed locus, aeg-46.5, which is located at min 46.5 on Escherichia coli linkage map, was cloned and analyzed. The phenotype of this gene was studied by using a lacZ operon fusion. aeg-46.5 is induced anaerobically in the presence of nitrate in wild-type and narL cells. It is repressed by the narL gene product, as it showed derepressed anaerobic expression in narL mutant cells. We postulate that aeg-46.5 is subject to multiple regulatory systems, activation as a result of anaerobiosis, narL-independent nitrate-dependent activation, and narL-mediated repression. The regulatory region of aeg-46.5 was identified. A 304-bp DNA sequence which includes the regulatory elements was obtained, and the 5' end of aeg-46.5 mRNA was identified. It was verified that the anaerobic regulation of aeg-46.5 expression is controlled on the transcriptional level. Computer analysis predicted possible control sites for the NarL and FNR proteins. The proposed NarL site was found in a perfect-symmetry element. The aeg-46.5 regulatory elements are adjacent to, but divergent from, those of the eco gene. Images PMID:8432709

  12. Anaerobic characteristics in male children and adolescents.

    PubMed

    Inbar, O; Bar-Or, O

    1986-06-01

    Only sparse information has been published on the effects of growth, development, and maturation on the ability to perform high intensity, short-term "anaerobic" tasks. Cross-sectional studies on Italian, African, British, and American females and males have indicated an age-related progression in the performance of the Margaria step-running test. Children had a distinctly lower mechanical power output than adolescents and young adults, both in absolute terms and when divided by body weight, or by fat-free mass. Data are presented on some 300 10- to 45-yr-old Israeli males who performed the Wingate anaerobic test by cycling or by arm cranking. Both the peak power at any 5-s period and the mean power throughout the test were lowest in the children, whether expressed in absolute power units or corrected for body weight. Performance progressed with age and reached the highest values at the end of the third decade for cycling and at the end of the second decade for arm cranking. This pattern is unlike that described for maximal O2 uptake per kg body weight which, in males, remains virtually unchanged from childhood to young adulthood. In females, maximal O2 uptake per kg is even higher in children than among adolescents or adults. Biochemical correlates of such a low anaerobic performance in children are their lower maximal lactate concentration in muscle and blood, lower rate of anaerobic glycolysis, and lower levels of acidosis at maximal exercise. The mechanisms for the relatively deficient anaerobic characteristics of children are not clear.

  13. Energy metabolism of the anaerobic protozoon Giardia lamblia.

    PubMed

    Lindmark, D G

    1980-03-01

    Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.

  14. Anaerobic animals from an ancient, anoxic ecological niche

    PubMed Central

    2010-01-01

    Tiny marine animals that complete their life cycle in the total absence of light and oxygen are reported by Roberto Danovaro and colleagues in this issue of BMC Biology. These fascinating animals are new members of the phylum Loricifera and possess mitochondria that in electron micrographs look very much like hydrogenosomes, the H2-producing mitochondria found among several unicellular eukaryotic lineages. The discovery of metazoan life in a permanently anoxic and sulphidic environment provides a glimpse of what a good part of Earth's past ecology might have been like in 'Canfield oceans', before the rise of deep marine oxygen levels and the appearance of the first large animals in the fossil record roughly 550-600 million years ago. The findings underscore the evolutionary significance of anaerobic deep sea environments and the anaerobic lifestyle among mitochondrion-bearing cells. They also testify that a fuller understanding of eukaryotic and metazoan evolution will come from the study of modern anoxic and hypoxic habitats. PMID:20370917

  15. Numerical modeling of oxygen exclusion experiments of anaerobic bioventing

    NASA Astrophysics Data System (ADS)

    Mihopoulos, Philip G.; Suidan, Makram T.; Sayles, Gregory D.; Kaskassian, Sebastien

    2002-10-01

    A numerical and experimental study of transport phenomena underlying anaerobic bioventing (ABV) is presented. Understanding oxygen exclusion patterns in vadose zone environments is important in designing an ABV process for bioremediation of soil contaminated with chlorinated solvents. In particular, the establishment of an anaerobic zone of influence by nitrogen injection in the vadose zone is investigated. Oxygen exclusion experiments are performed in a pilot scale flow cell (2×1.1×0.1 m) using different venting flows and two different outflow boundary conditions (open and partially covered). Injection gas velocities are varied from 0.25×10 -3 to 1.0×10 -3 cm/s and are correlated with the ABV radius of influence. Numerical simulations are used to predict the collected experimental data. In general, reasonable agreement is found between observed and predicted oxygen concentrations. Use of impervious covers can significantly reduce the volume of forcing gas used, where an increase in oxygen exclusion efficiency is consistent with a decrease in the outflow area above the injection well.

  16. Numerical modeling of oxygen exclusion experiments of anaerobic bioventing.

    PubMed

    Mihopoulos, Philip G; Suidan, Makram T; Sayles, Gregory D; Kaskassian, Sebastien

    2002-10-01

    A numerical and experimental study of transport phenomena underlying anaerobic bioventing (ABV) is presented. Understanding oxygen exclusion patterns in vadose zone environments is important in designing an ABV process for bioremediation of soil contaminated with chlorinated solvents. In particular, the establishment of an anaerobic zone of influence by nitrogen injection in the vadose zone is investigated. Oxygen exclusion experiments are performed in a pilot scale flow cell (2 x 1.1 x 0.1 m) using different venting flows and two different outflow boundary conditions (open and partially covered). Injection gas velocities are varied from 0.25 x 10(-3) to 1.0 x 10(-3) cm/s and are correlated with the ABV radius of influence. Numerical simulations are used to predict the collected experimental data. In general, reasonable agreement is found between observed and predicted oxygen concentrations. Use of impervious covers can significantly reduce the volume of forcing gas used, where an increase in oxygen exclusion efficiency is consistent with a decrease in the outflow area above the injection well.

  17. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures.

    PubMed

    Oliver, Christy E; Beier, Ross C; Hume, Michael E; Horrocks, Shane M; Casey, Thomas A; Caton, Joel S; Nisbet, David J; Smith, David J; Krueger, Nathan A; Anderson, Robin C

    2010-04-01

    Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by

  18. Anaerobic protozoa and their growth in biomethanation systems.

    PubMed

    Priya, M; Haridas, Ajit; Manilal, V B

    2008-04-01

    This study was to investigate growth of protozoa and its influence on biodegradation in anaerobic treatment systems. It was done by specifically controlling and monitoring growth of protozoa versus degradation in continuous stirred anaerobic reactors and batch anaerobic reactors. Occurrence of a diverse protozoa population such as the ciliates, Prorodon, Vorticella, Cyclidium, Spathidium, Loxodes, Metopus were observed in stable anaerobic systems and the flagellates, Rhynchomonas, Naeglaria, Amoeboflagellates, Tetramitus, Trepomonas and Bodo during increased VFA concentration and affected periods of biomethanation. The abundance of ciliates in the anaerobic system had significant correlation with the reduction of MLSS, increased rate of COD removal and higher methane production. The results of this study thus tend to relate increased anaerobic degradation with the abundance of protozoa, mainly ciliates, which indicate their possible involvement in the process. Present study also reveals that performance of anaerobic process can be assessed by monitoring the protozoa population in the system.

  19. Transcription of genes coding for metabolic key functions in Nitrosomonas europaea during aerobic and anaerobic growth.

    PubMed

    Beyer, Sonja; Gilch, Stefan; Meyer, Ortwin; Schmidt, Ingo

    2009-01-01

    Nitrosomonas europaea can grow under conditions of chemolithoautotrophic aerobic (oxygen as oxidant) as well as anaerobic [nitrogen dioxide (NO(2)) as oxidant] nitrification or chemoorganotrophic anaerobic pyruvate-dependent denitrification. In this study, the adaptation of the transcription (mRNA synthesis/concentration) of N. europaea to aerobic and anaerobic growth conditions was evaluated and the transcription of genes coding for metabolic key functions was analyzed: nitrogen and energy metabolism (amoA, hao, rh1, nirK, norB, nsc, aceE, ldhA, ppc, gltA, odhA, coxA), carbon dioxide fixation (cbbL), gluconeogenesis (ppsA), cell growth (ftsZ), and oxidative stress (sodB). During aerobic ammonia oxidation the specific activities of ammonia oxidation, nitrite reduction, and the growth rates correlated with the transcription level of the corresponding genes amoA/hao, nirK/norB/nsc, and cbbL/ftsZ. In anaerobically ammonia-oxidizing cells of N. europaea, the cellular mRNA concentrations of amoA, hao, rh1,coxA, cbbL, ftsZ, and sodB were reduced compared with aerobically nitrifying cells, but the mRNA levels of nirK, norB, and nsc were significantly increased. During anaerobic pyruvate-dependent denitrification, the mRNA abundance of nirK, norB, nsc, aceE, gltA, and odhA was increased, while the concentrations of amoA,hao, rh1, coxAcbbL, ftsZ, and sodB were significantly reduced. Temperature, pH value, and NH(4)(+), O(2), NO, and NO(2) concentrations had comparatively small effects on the transcription of the studied genes.

  20. Enzymatic evidence for an involvement of pyruvate dehydrogenase in the anaerobic glycerol metabolism of Klebsiella pneumoniae.

    PubMed

    Menzel, K; Zeng, A P; Deckwer, W D

    1997-08-11

    Stoichiometric analysis of pathways involved in anaerobic bioconversion of glycerol by Klebsiella pneumoniae revealed that enzyme(s) in addition to pyruvate formate-lyase (PFL) must be involved in pyruvate decarboxylation. In this work, enzymatic evidence is presented that confirmed a simultaneous involvement of pyruvate dehydrogenase complex (PDH) and excluded the presence of pyruvate:ferredoxin oxidoreductase in this anaerobic bioprocess. The in vitro PDH activity of cell extract from continuous culture was found to be strongly affected by the substrate (glycerol) concentration in medium and cell growth rate (dilution rate). It increases with increasing glycerol concentration and correlates well with the specific substrate uptake rate at different dilution rates in a kind of saturation function. At a similar substrate uptake rate, it decreases with cell growth rate. The in vitro activity of PDH is much higher than its in vivo activity calculated from the pathway stoichiometry but comparable to the calculated in vivo activity of PFL.

  1. Increased ethanol production with UV-C mutagenized Kluyveromyces marxianus capable of anaerobic growth at elevated temperature on pentose and hexose sugars using fermentation strategies with corn pericarp hydrolysates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several novel Kluyveromyces marxianus strains were obtained by irradiation with UV-C (UV-C 234nm) to achieve an 80% mortality rate. The surviving cells were subsequently grown anaerobically for 5 months at 46C and resulted in two mutagenized strains that were able to grow anaerobically at elevated ...

  2. Antimicrobial Susceptibility of Enteric Gram Negative Facultative Anaerobe Bacilli in Aerobic versus Anaerobic Conditions

    PubMed Central

    Amachawadi, Raghavendra G.; Renter, David G.; Volkova, Victoriya V.

    2016-01-01

    Antimicrobial treatments result in the host’s enteric bacteria being exposed to the antimicrobials. Pharmacodynamic models can describe how this exposure affects the enteric bacteria and their antimicrobial resistance. The models utilize measurements of bacterial antimicrobial susceptibility traditionally obtained in vitro in aerobic conditions. However, in vivo enteric bacteria are exposed to antimicrobials in anaerobic conditions of the lower intestine. Some of enteric bacteria of food animals are potential foodborne pathogens, e.g., Gram-negative bacilli Escherichia coli and Salmonella enterica. These are facultative anaerobes; their physiology and growth rates change in anaerobic conditions. We hypothesized that their antimicrobial susceptibility also changes, and evaluated differences in the susceptibility in aerobic vs. anaerobic conditions of generic E. coli and Salmonella enterica of diverse serovars isolated from cattle feces. Susceptibility of an isolate was evaluated as its minimum inhibitory concentration (MIC) measured by E-Test® following 24 hours of adaptation to the conditions on Mueller-Hinton agar, and on a more complex tryptic soy agar with 5% sheep blood (BAP) media. We considered all major antimicrobial drug classes used in the U.S. to treat cattle: β-lactams (specifically, ampicillin and ceftriaxone E-Test®), aminoglycosides (gentamicin and kanamycin), fluoroquinolones (enrofloxacin), classical macrolides (erythromycin), azalides (azithromycin), sulfanomides (sulfamethoxazole/trimethoprim), and tetracyclines (tetracycline). Statistical analyses were conducted for the isolates (n≥30) interpreted as susceptible to the antimicrobials based on the clinical breakpoint interpretation for human infection. Bacterial susceptibility to every antimicrobial tested was statistically significantly different in anaerobic vs. aerobic conditions on both media, except for no difference in susceptibility to ceftriaxone on BAP agar. A satellite experiment

  3. In situ detection of anaerobic alkane metabolites in subsurface environments.

    PubMed

    Agrawal, Akhil; Gieg, Lisa M

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contributing to modern-day detrimental effects such as oilfield souring, or may lead to more beneficial technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes) metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments.

  4. In situ detection of anaerobic alkane metabolites in subsurface environments

    PubMed Central

    Agrawal, Akhil; Gieg, Lisa M.

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contributing to modern-day detrimental effects such as oilfield souring, or may lead to more beneficial technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes) metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments. PMID:23761789

  5. Biochemistry and evolution of anaerobic energy metabolism in eukaryotes.

    PubMed

    Müller, Miklós; Mentel, Marek; van Hellemond, Jaap J; Henze, Katrin; Woehle, Christian; Gould, Sven B; Yu, Re-Young; van der Giezen, Mark; Tielens, Aloysius G M; Martin, William F

    2012-06-01

    Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified.

  6. Note: Small anaerobic chamber for optical spectroscopy

    PubMed Central

    Chauvet, Adrien A. P.; Agarwal, Rachna; Cramer, William A.; Chergui, Majed

    2015-01-01

    The study of oxygen-sensitive biological samples requires an effective control of the atmosphere in which they are housed. In this aim however, no commercial anaerobic chamber is adequate to solely enclose the sample and small enough to fit in a compact spectroscopic system with which analysis can be performed. Furthermore, spectroscopic analysis requires the probe beam to pass through the whole chamber, introducing a requirement for adequate windows. In response to these challenges, we present a 1 l anaerobic chamber that is suitable for broad-band spectroscopic analysis. This chamber has the advantage of (1) providing access, via a septum, to the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment. PMID:26520998

  7. Note: Small anaerobic chamber for optical spectroscopy

    SciTech Connect

    Chauvet, Adrien A. P. Chergui, Majed; Agarwal, Rachna; Cramer, William A.

    2015-10-15

    The study of oxygen-sensitive biological samples requires an effective control of the atmosphere in which they are housed. In this aim however, no commercial anaerobic chamber is adequate to solely enclose the sample and small enough to fit in a compact spectroscopic system with which analysis can be performed. Furthermore, spectroscopic analysis requires the probe beam to pass through the whole chamber, introducing a requirement for adequate windows. In response to these challenges, we present a 1 l anaerobic chamber that is suitable for broad-band spectroscopic analysis. This chamber has the advantage of (1) providing access, via a septum, to the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment.

  8. Note: Small anaerobic chamber for optical spectroscopy.

    PubMed

    Chauvet, Adrien A P; Agarwal, Rachna; Cramer, William A; Chergui, Majed

    2015-10-01

    The study of oxygen-sensitive biological samples requires an effective control of the atmosphere in which they are housed. In this aim however, no commercial anaerobic chamber is adequate to solely enclose the sample and small enough to fit in a compact spectroscopic system with which analysis can be performed. Furthermore, spectroscopic analysis requires the probe beam to pass through the whole chamber, introducing a requirement for adequate windows. In response to these challenges, we present a 1 l anaerobic chamber that is suitable for broad-band spectroscopic analysis. This chamber has the advantage of (1) providing access, via a septum, to the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment.

  9. The role of anaerobic sludge recycle in improving anaerobic digester performance.

    PubMed

    Young, Michelle N; Krajmalnik-Brown, Rosa; Liu, Wenjun; Doyle, Michael L; Rittmann, Bruce E

    2013-01-01

    Solids retention time (SRT) is a critical parameter for the performance of anaerobic digesters (AD) in wastewater treatment plants. AD SRT should increase when active biomass is input to the AD by recycling anaerobic sludge via the wastewater-treatment tanks, creating a hybrid aerobic/anaerobic system. When 85% of the flow through the AD was recycled in pilot-scale hybrid systems, the AD SRT increased by as much as 9-fold, compared to a parallel system without anaerobic-sludge recycle. Longer AD SRTs resulted in increased hydrolysis and methanogenesis in the AD: net solids yield decreased by 39-96% for overall and 23-94% in the AD alone, and AD methane yield increased 1.5- to 5.5-fold. Microbial community assays demonstrated higher, more consistent Archaea concentrations in all tanks in the wastewater-treatment system with anaerobic-sludge recycle. Thus, multiple lines of evidence support that AD-sludge recycle increased AD SRT, solids hydrolysis, and methane generation.

  10. Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms▿

    PubMed Central

    Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

    2009-01-01

    In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus. PMID:19363082

  11. Anaerobic contribution during maximal anaerobic running test: correlation with maximal accumulated oxygen deficit.

    PubMed

    Zagatto, A; Redkva, P; Loures, J; Kalva Filho, C; Franco, V; Kaminagakura, E; Papoti, M

    2011-12-01

    The aims of this study were: (i) to measure energy system contributions in maximal anaerobic running test (MART); and (ii) to verify any correlation between MART and maximal accumulated oxygen deficit (MAOD). Eleven members of the armed forces were recruited for this study. Participants performed MART and MAOD, both accomplished on a treadmill. MART consisted of intermittent exercise, 20 s effort with 100 s recovery, after each spell of effort exercise. Energy system contributions by MART were also determined by excess post-exercise oxygen consumption, lactate response, and oxygen uptake measurements. MAOD was determined by five submaximal intensities and one supramaximal intensity exercises corresponding to 120% at maximal oxygen uptake intensity. Energy system contributions were 65.4±1.1% to aerobic; 29.5±1.1% to anaerobic a-lactic; and 5.1±0.5% to anaerobic lactic system throughout the whole test, while only during effort periods the anaerobic contribution corresponded to 73.5±1.0%. Maximal power found in MART corresponded to 111.25±1.33 mL/kg/min but did not significantly correlate with MAOD (4.69±0.30 L and 70.85±4.73 mL/kg). We concluded that the anaerobic a-lactic system is the main energy system in MART efforts and this test did not significantly correlate to MAOD.

  12. Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment.

    PubMed

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Yuan, Zhiguo

    2016-05-01

    In some wastewater treatment plants (WWTPs), the ever increasing production of sludge with the expanding population overloaded the anaerobic digestion which compromises the sludge reduction efficiency. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, to a very limited extent. This study verified the effectiveness of free nitrous acid (FNA i.e. HNO2) pre-treatment on enhancing full-scale ADS degradation in post anaerobic digestion. The ADS collected from a full-scale WWTP was subject to FNA treatment at concentrations of 0.77, 1.54, 2.31, 3.08, and 3.85 mg N/L for 24 h followed by biochemical methane potential tests. The FNA treatment at all concentrations resulted in an increase (from 1.5-3.1 % compared to the control) in sludge reduction with the highest improvement achieved at 0.77 mg HNO2-N/L. The FNA treatment at this concentration also resulted in the highest increase in methane production (40 %) compared to the control. The economic analysis indicates that FNA treatment is economically attractive for enhancing post anaerobic digestion of full-scale ADS.

  13. [Anaerobic humus respiration by Shewanella cinica D14T].

    PubMed

    Xu, Zhi-cheng; Hong, Yi-guo; Luo, Wei; Chen, Xing-juan; Sun, Guo-ping; Xu, Mei-ying; Guo, Jun; Cen, Ying-hua

    2006-12-01

    Experimental results suggested Shewanella cinica D14T is capable of humus respiration utilizing various organic acids and some important environmental pollutants (e.g., toluene. etc) as electron donors and AQS or AQDS as a sole terminal electron acceptor under anaerobic condition. The dissimilatory reduction of 1mmol/L AQDS can couple to the production of enough ATP to support cell growth about 60 generations; The oxidization of electron donors was coupled to the reduction of humus, as reduced humus increased corresponding with increasing of electron donor; The typical inhibitors such as Cu2+ which inhibited Fe-S center, Stigmatellin which was methyl-naphthoquinone model, Dicumarol which inhibited oxidized methyl-naphthoquinone transform to reduced one, Metyrapone which was specific inhibitor for P450 enzyme blocked the humus respiration seriously. These were powerful evidences for humus-respiration by D14.

  14. Hog farm in California uses anaerobic digestion

    SciTech Connect

    Swanson, D.

    1995-12-31

    This article describes a system of covered lagoons which help address the waste management problems of hog farmers as well as producing methane used to power generators. Four advantages of anaerobic digestion are described along with the system: energy production from methane; fertilizer for fields; economic development in rural areas; and improved water quality through reduction of nonpoint source pollution. Address for full report is given.

  15. Manganese Dependent Anaerobic Oxidation of Methane

    NASA Astrophysics Data System (ADS)

    Beal, E.; House, C.

    2007-12-01

    Understanding the anaerobic oxidation is not only important for understanding hydrocarbon degradation but it also important for understanding the global carbon cycle. The anaerobic oxidation of methane (AOM) is a large sink for methane consuming 5-20% of today's methane flux (Valentine and Reeburgh, 2000), yet the requirements for this process are not well understood. It has been suggested that no other electron acceptors other than sulfate can be used in the AOM (Nauhaus, 2005). However, our new data suggests that manganese, in the form of birnessite, can be used as an electron acceptor instead of sulfate (Beal et al., in prep). Methane seep sediment from the Eel River Basin, CA was incubated with methane, 13C-labeled methane, and carbon dioxide. Because the net result of the AOM is the production of carbon dioxide from methane, the rate of the AOM in each of the incubations can be determined by measuring the incorporation of 13C in the carbon dioxide. Using this method, it was found that cultures incubated with nitrate showed inhibition of the AOM, while cultures incubated with iron gave inconclusive results. The only positive results that were found for alternate electron acceptors are the incubations that were given manganese and no sulfate, which showed methane oxidation. Further, when more manganese was injected into these incubations, the rate of AOM increased. Preliminary analysis of the microbial population using terminal restriction fragment length polymorphism (TRFLP) targeting the mcr gene showed an unidentified organism in these cultures. Future work with TRFLP, as well as clone libraries, will help to identify the organisms responsible for this process. Nauhaus, K., 2005, Environmental regulation of the anaerobic oxidation of methane: a comparison of ANME-I and ANME-II communities: Environmental microbiology, v. 7, p. 98. Valentine, D.L., and Reeburgh, W.S., 2000, New perspectives on anaerobic methane oxidation: Environmental Microbiology, v. 2, p

  16. Anaerobic digestion of municipal solid waste

    SciTech Connect

    Dasgupta, A.; Nemerow, N.L.; Farooq, S.; Daly, E.L. Jr.; Sengupta, S.; Gerrish, H.P.; Wong, K.F.

    1981-03-01

    A demonstration anaerobic digestion plant has been installed at Pompano Beach, Florida, capable of treating 100 tons per day of municipal solid waste. The suitability of this process and its environmental effects at a full scale operation level is being examined. The study presented and discussed in this paper had as its main objective the characterization of various waste streams and an assessment of their environmental effects if discharged into the environment.

  17. Anaerobic microbiology in the NASA space program.

    PubMed

    Brewer, J H

    1980-01-01

    After briefly reviewing the earlier methods used to monitor the microbial load of returned lunar material, the author reports the more accurate research on the ability of terrestrial organisms to grow under simulated Martian environments. The possible importance of anaerobic microbiology can readily be seen because of the low level of O2 found on Mars. The question of whether any of the experiments on board the Viking landers show any indication of life on Mars is discussed in detail.

  18. Recent development of anaerobic digestion processes for energy recovery from wastes.

    PubMed

    Nishio, Naomichi; Nakashimada, Yutaka

    2007-02-01

    Anaerobic digestion leads to the overall gasification of organic wastewaters and wastes, and produces methane and carbon dioxide; this gasification contributes to reducing organic matter and recovering energy from organic carbons. Here, we propose three new processes and demonstrate the effectiveness of each process. By using complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment, the chemical oxygen demand (COD) in wastewater was decreased to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge, cow feces, chicken feces, and food waste without the dilution of the ammonia produced by water or carbon-rich wastes. The hydrogen-methane two-stage fermentation (Hy-Met process), in which the hydrogen produced in the first stage is used for a fuel cell system to generate electricity and the methane produced in the second stage is used to generate heat energy to heat the two reactors and satisfy heat requirements, is useful for the treatment of sugar-rich wastewaters, bread wastes, and biodiesel wastewaters.

  19. Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester)

    PubMed Central

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

    2014-01-01

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086

  20. Some unique features of alkaliphilic anaerobes

    NASA Astrophysics Data System (ADS)

    Roof, Erin; Pikuta, Elena; Otto, Christopher; Williams, George; Hoover, Richard

    2013-09-01

    This article explores two topics involving the examination of four strains of alkaliphilic anaerobes. The first topic was dedicated to detection of the ability of microorganisms to metabolize alternative chirality substrates. Two saccharolytic anaerobic bacteria were chosen for the first experiment: Anaerovirgula multivorans strain SCAT, which is gram positive and spore-forming; and Spirochaeta dissipatitropha, strain ASpC2T, which is gram negative. It was found that both checked sugarlytics were able to use L-ribose and L-arabinose, as growth substrates. The second part was concerned of study a chemolithotrophy in two halo-alkaliphilic sulfate reducing bacteria: Desulfonatornum thiodismutans strain MLF1T and Desulfonatronum lacustre strain Z-7951T. The experiments with lithotrophs had demonstrated that strain MLF1T was capable to grow without any organic source of carbon, while strain Z-7951T had required at least 2 mM sodium acetate for growth. Anaerobic technique was used for preparation of the growth media and maintenance of these bacterial cultures. Standard methods for Gram, spore, and flagella staining were applied for characterization of cytomorphology. In this article, the results of the experiments performed on cytological, physiological, and biochemical levels are presented and discussed.

  1. Biogeochemistry of anaerobic crude oil biodegradation

    NASA Astrophysics Data System (ADS)

    Head, Ian; Gray, Neil; Aitken, Caroline; Sherry, Angela; Jones, Martin; Larter, Stephen

    2010-05-01

    Anaerobic degradation of crude oil and petroleum hydrocarbons is widely recognized as a globally significant process both in the formation of the world's vast heavy oil deposits and for the dissipation of hydrocarbon pollution in anoxic contaminated environments. Comparative analysis of crude oil biodegradation under methanogenic and sulfate-reducing conditions has revealed differences not only in the patterns of compound class removal but also in the microbial communities responsible. Under methanogenic conditions syntrophic associations dominated by bacteria from the Syntropheaceae are prevalent and these are likely key players in the initial anaerobic degradation of crude oil alkanes to intermediates such as hydrogen and acetate. Syntrophic acetate oxidation plays an important role in these systems and often results in methanogenesis dominated by CO2 reduction by members of the Methanomicrobiales. By contrast the bacterial communities from sulfate-reducing crude oil-degrading systems were more diverse and no single taxon dominated the oil-degrading sulfate-reducing systems. All five proteobacterial subdivisions were represented with Delta- and Gammaproteobacteria being detected most consistently. In sediments which were pasteurized hydrocarbon degradation continued at a relatively low rate. Nevertheless, alkylsuccinates characteristic of anaerobic hydrocarbon degradation accumulated to high concentrations. This suggested that the sediments harbour heat resistant, possibly spore-forming alkane degrading sulfate-reducers. This is particularly interesting since it has been proposed recently, that spore-forming sulfate-reducing bacteria found in cold arctic sediments may have originated from seepage of geofluids from deep subsurface hydrocarbon reservoirs.

  2. Cadmium removal by Euglena gracilis is enhanced under anaerobic growth conditions.

    PubMed

    Santiago-Martínez, M Geovanni; Lira-Silva, Elizabeth; Encalada, Rusely; Pineda, Erika; Gallardo-Pérez, Juan Carlos; Zepeda-Rodriguez, Armando; Moreno-Sánchez, Rafael; Saavedra, Emma; Jasso-Chávez, Ricardo

    2015-05-15

    The facultative protist Euglena gracilis, a heavy metal hyper-accumulator, was grown under photo-heterotrophic and extreme conditions (acidic pH, anaerobiosis and with Cd(2+)) and biochemically characterized. High biomass (8.5×10(6)cellsmL(-1)) was reached after 10 days of culture. Under anaerobiosis, photosynthetic activity built up a microaerophilic environment of 0.7% O₂, which was sufficient to allow mitochondrial respiratory activity: glutamate and malate were fully consumed, whereas 25-33% of the added glucose was consumed. In anaerobic cells, photosynthesis but not respiration was activated by Cd(2+) which induced higher oxidative stress. Malondialdehyde (MDA) levels were 20 times lower in control cells under anaerobiosis than in aerobiosis, although Cd(2+) induced a higher MDA production. Cd(2+) stress induced increased contents of chelating thiols (cysteine, glutathione and phytochelatins) and polyphosphate. Biosorption (90%) and intracellular accumulation (30%) were the mechanisms by which anaerobic cells removed Cd(2+) from medium, which was 36% higher versus aerobic cells. The present study indicated that E. gracilis has the ability to remove Cd(2+) under anaerobic conditions, which might be advantageous for metal removal in sediments from polluted water bodies or bioreactors, where the O₂ concentration is particularly low.

  3. Importance of tetrahydrofolate and ATP in the anaerobic O-demethylation reaction for phenylmethylethers

    SciTech Connect

    Berman, M.H.; Frazer, A.C. )

    1992-03-01

    DL-Tetrahydrofolate (THF) and ATP were necessary for the anaerobic O-demethylation of phenylmethylethers in cell extracts of the type strain (ATCC 29683) of the homoacetogen Acetobacterium woodii. The reactants for this enzymatic activity have not been previously demonstrated in any system, nor has the mediating enzyme been studied. An assay using reaction mixtures containing 1 mM THF, 2 mM ATP, and 2 mM hydroferulate (i.e., 4-hydroxy,3-methoxyphenylpropionate) was developed and was performed under stringent anaerobic conditions. Pyridine nucleotides and several other possible cofactors were tested but had no effect on the activity. After centrifugation of disrupted cells at 27,000 x g, the activity was found primarily in the supernatant, which had a specific activity of 14.2 {plus minus} 0.5 nmol/min/mg of protein. At saturating levels of each of the other two substrates, apparent K{sub m} values for the variable substrate were 0.65 mM hydroferulate, 0.27 mM ATP, and 0.17 mM THF. Activity was significantly decreased when extract was preincubated at 60C and was completely lost after preincubation in air for 30 min. Thus, the soluble anaerobic O-demethylating enzyme system of A. woodii is oxygen sensitive. The THF- and ATP-dependent activity measurable in the soluble fraction of cell extracts constituted about 34% of the activity seen with intact cells.

  4. Anaerobic filters for the treatment of coal gasification wastewater.

    PubMed

    Suidan, M T; Siekerka, G L; Kao, S W; Pfeffer, J T

    1983-06-01

    A process train consisting of the following sequence of unit processes, a berl-saddle-packed anaerobic filter, an expanded bed, granular activated carbon anaerobic filter, and an activated sludge nitrification system was evaluated for the treatment of a synthetically prepared coal gasification wastewater. The first-stage anaerobic filter resulted in very little removal of organic matter and no methane production. Excellent reduction in organic matter occurred in the granular activated carbon anaerobic filter. The removal mechanism was initially adsorptive and near the end of the study, removal of organic matter was primarily through conversion to methane gas. It is felt that the success of the activated carbon anaerobic filter was due to the ability of the activated carbon to sequester some components of the wastewater that were toxic to the mixed culture of anaerobic microorganisms. The activated sludge nitrification system resulted in complete ammonia oxidation and was very efficient in final effluent polishing.

  5. Aerobic and anaerobic cellulase production by Cellulomonas uda.

    PubMed

    Poulsen, Henrik Vestergaard; Willink, Fillip Wolfgang; Ingvorsen, Kjeld

    2016-10-01

    Cellulomonas uda (DSM 20108/ATCC 21399) is one of the few described cellulolytic facultative anaerobes. Based on these characteristics, we initiated a physiological study of C. uda with the aim to exploit it for cellulase production in simple bioreactors with no or sporadic aeration. Growth, cellulase activity and fermentation product formation were evaluated in different media under both aerobic and anaerobic conditions and in experiments where C. uda was exposed to alternating aerobic/anaerobic growth conditions. Here we show that C. uda behaves as a true facultative anaerobe when cultivated on soluble substrates such as glucose and cellobiose, but for reasons unknown cellulase activity is only induced under aerobic conditions on insoluble cellulosic substrates and not under anaerobic conditions. These findings enhance knowledge on the limited number of described facultative cellulolytic anaerobes, and in addition it greatly limits the utility of C. uda as an 'easy to handle' cellulase producer with low aeration demands.

  6. Enhancement of Taihu blue algae anaerobic digestion efficiency by natural storage.

    PubMed

    Miao, Hengfeng; Lu, Minfeng; Zhao, Mingxing; Huang, Zhenxing; Ren, Hongyan; Yan, Qun; Ruan, Wenquan

    2013-12-01

    Taihu blue algae after different storage time from 0 to 60 d were anaerobic fermented to evaluate their digestibility and process stability. Results showed that anaerobic digestion (AD) of blue algae under 15 d natural storage led to the highest CH4 production of 287.6 mL g(-1) VS at inoculum substrate ratio 2.0, demonstrating 36.69% improvement comparing with that from fresh algae. Storage of blue algae led to cell death, microcystins (MCs) release and VS reduction by spontaneous fermentation. However, it also played an important role in removing algal cell wall barrier, pre-hydrolysis and pre-acidification, leading to the improvement in CH4 yield. Closer examination of volatile fatty acids (VFA) variation, VS removal rates and key enzymes change during AD proved short storage time (≤ 15 d) of blue algae had higher efficiencies in biodegradation and methanation. Furthermore, AD presented significant biodegradation potential for MCs released from Taihu blue algae.

  7. Behavior of carbon monoxide as a trace component of anaerobic digester gases and methanogenesis from acetate

    SciTech Connect

    Hickey, R.F. ); Switzenbaum, M.S. )

    1990-11-01

    Carbon monoxide was a normal trace component of the gases produced during anaerobic sludge digestion. The CO concentration increased in response to perturbing the digestion process by increasing organic loading or adding acetate. Reducing the headspace methane level resulted in higher measured CO concentrations. Accordingly, a thermodynamic relationship was developed by dividing the acetoclastic methane reaction into two half-cell reactions, representing production of and subsequent oxidation of CO. A constant fraction of the total free energy available for acetate conversion to methane was assigned to each half-cell based on the basis of experimental observations. It was determined that approximately 54% of the energy available for acetate conversion to methane was consistently associated with the anaerobic oxidation of CO to carbon dioxide. Estimated values compared well for measured concentrations for both mesophilic and thermophilic digesters operating under steady-state conditions.

  8. Initiation of Anaerobic Degradation of p-Cresol by Formation of 4-Hydroxybenzylsuccinate in Desulfobacterium cetonicum

    PubMed Central

    Müller, Jochen A.; Galushko, Alexander S.; Kappler, Andreas; Schink, Bernhard

    2001-01-01

    The anaerobic bacterium Desulfobacterium cetonicum oxidized p-cresol completely to CO2 with sulfate as the electron acceptor. During growth, 4-hydroxybenzylsuccinate accumulated in the medium. This finding indicated that the methyl group of p-cresol is activated by addition to fumarate, analogous to anaerobic toluene, m-xylene, and m-cresol degradation. In cell extracts, the formation of 4-hydroxybenzylsuccinate from p-cresol and fumarate was detected at an initial rate of 0.57 nmol min−1 (mg of protein)−1. This activity was specific for extracts of p-cresol-grown cells. 4-Hydroxybenzylsuccinate was degraded further to 4-hydroxybenzoyl-coenzyme A (CoA), most likely via β-oxidation. 4-Hydroxybenzoyl-CoA was reductively dehydroxylated to benzoyl-CoA. There was no evidence of degradation of p-cresol via methyl group oxidation by p-cresol-methylhydroxylase in this bacterium. PMID:11133971

  9. Anaerobic Metabolism and Bioremediation of Explosives-Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Boopathy, Raj

    Nitroaromatic compounds pollute soil, water, and food via use of pesticides, plastics, pharmaceuticals, landfill dumping of industrial wastes, and the military use of explosives. Biotransformation of trinitrotoluene and other nitroaromatics by aerobic bacteria in the laboratory has been frequently reported, but the anaerobic bacterial metabolism of nitroaromatics has not been studied as extensively perhaps due to the difficulty in working with anaerobic cultures and the slow growth of anaerobes. Sulfate-reducing and methanogenic bacteria can metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment.

  10. Isolation and partial characterization of bacteria in an anaerobic consortium that mineralizes 3-chlorobenzoic acid

    SciTech Connect

    Shelton, D.R.; Tiedje, J.M.

    1984-10-01

    A methanogenic consortium able to use 3-chlorobenzoic acid as its sole energy and carbon source was enriched from anaerobic sewage sludge. Seven bacteria were isolated from the consortium in mono- or coculture. They included: one dechlorinating bacterium, one benzoate-oxidizing bacterium, two butyrate-oxidizing bacteria, two H/sub 2/-consuming methanogens (methanospirillum hungatei PM-1 and Methanobacterium sp. strain PM-2), and a sulfate-reducing bacterium (Desulfovibrio sp.). The dechlorinating bacterium was a gram-negative, obligate anaerobe with a unique collar surrounding the cell. A medium containing rumen fluid supported minimal growth; pyruvate was the only substrate found to increase growth. The bacterium had a generation time of 4 to 5 days. 3-Chlorobenzoate was dechlorinated stoichiometrically to benzoate, which accumulated in the medium; the rate of dechlorination was ca. 0.1 pmol bacterium/sup -1/ day/sup -1/. The benzoate-oxidizing bacterium was a gram-negative, obligate anaerobe and could only be grown as a syntroph. Benzoate was the only substrate observed to support growth, and, when grown in coculture with M. hungatei, it was fermented to acetate and CH/sub 4/. One butyrate-oxidizing bacterium was a gram-negative, non-sporeforming, obligate anaerobe; the other was a gram-positive, sporeforming, obligate anaerobe. Both could only be grown as syntrophs. The substrates observed to support growth of both bacteria were butyrate, 2-DL-methylbutyrate, valerate, and caproate; isobutyrate supported growth of only the sporeforming bacterium. Fermentation products were acetate and CH/sub 4/ or acetate, propionate, and CH/sub 4/ when grown in coculture with M. hungatei. A mutualism among at least the dechlorinating, benzoate-oxidizing, and methane-forming members was apparently required for utilization of the 3-chlorobenzoate substrate. 21 references, 8 figures, 2 tables.

  11. Isolation of a tannic acid-degrading Streptococcus sp. from an anaerobic shea cake digester.

    PubMed

    Nitiema, L W; Dianou, D; Simpore, J; Karou, S D; Savadogo, P W; Traore, A S

    2010-01-01

    An anaerobic digester fed with shea cake rich in tannins and phenolic compounds rich-shea cake and previously inoculated with anaerobic sludge from the pit of a slaughterhouse, enabled six months acclimatization of the bacteria to aromatic compounds. Afterwards, digester waste water samples were subject to successive culture on media with 1 g L(-1) tannic acid allowing the isolation of a bacterial strain coded AB. Strain AB was facultatively anaerobic, mesophilic, non-motile, non-sporulating, catalase and oxidase negative bacterium, namely strain AB, was isolated from an anaerobic digester fed with shea cake rich in tannins and phenolic compounds, after inoculation with anaerobic sludge from the pit of a slaughterhouse and enrichment on tannic acid. The coccoid cells occurred in pair, short or long chains and stained Gram-positive. Strain AB fermented a wide range of carbohydrates including glucose, fructose, galactose, raffinose, arabinose, sucrose, maltose, lactose, starch and cellulose. Optimum growth occurred with glucose and tannic acid at 37 degrees C and pH 8. The pH, temperature and salt concentration for growth ranged from 5 to 9, 20 to 45 degrees C and 0 to 15 g L(-1), respectively. Strain AB converted tannic acid to gallic acid. These features were similar to those of the Streptococcus genus. The determination of tannic acid hydrolysis end products, ability to utilize various organic acids, alcohols and peptides, GC% of the DNA, the sequencing of 16S rRNA gene and DNA-DNA hybridization will permit to confirm this affiliation and to determine the species.

  12. Anaerobic activities of bacteria and fungi in moderately acidic conifer and deciduous leaf litter.

    PubMed

    Reith, Frank; Drake, Harold L; Küsel, Kirsten

    2002-07-01

    Abstract The litter layer of forest soils harbors high amounts of labile organic matter, and anaerobic decomposition processes can be initiated when oxygen is consumed more rapidly than it is supplied by diffusion. In this study, two adjacent moderately acidic forest sites, a spruce and a beech-oak forest, were selected to compare the anaerobic bacterial and fungal activities and populations of conifer and deciduous leaf litter. Most probable number (MPN) estimates of general heterotrophic aerobes and anaerobes from conifer litter equaled those from deciduous leaf litter. H(2), ethanol, formate, and lactate were initially produced with similar rates in both anoxic conifer and deciduous leaf litter microcosms. These products were rapidly consumed in deciduous leaf but not in conifer litter microcosms. Supplemental ethanol and H(2) were consumed only by deciduous leaf litter and yielded additional amounts of acetate in stoichiometries indicative of ethanol- or H(2)-dependent acetogenesis. The negligible turnover of primary fermentation products in conifer litter might be due to the low numbers of acetogens and secondary fermenters present in conifer litter compared to deciduous leaf litter. Fungi capable of anaerobic growth made up only 0.01-0.1% of the total anaerobic microorganisms cultured from conifer and deciduous leaf litter, respectively. Metabolic product profiles obtained from the highest anoxic, growth-positive MPN dilutions supplemented with antibacterial agents indicated that the dominant population of fungi, apparently mainly yeast-like cells, produced H(2), ethanol, acetate, and lactate both in conifer and deciduous leaf litter. Thus, despite acidic conditions, bacteria appear to dominate in the decomposition of carbon in anoxic microsites of both conifer and deciduous leaf litter.

  13. Anaerobic Nitrogen Turnover by Sinking Diatom Aggregates at Varying Ambient Oxygen Levels

    PubMed Central

    Stief, Peter; Kamp, Anja; Thamdrup, Bo; Glud, Ronnie N.

    2016-01-01

    In the world’s oceans, even relatively low oxygen levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here, we show that sinking diatom aggregates can host anaerobic nitrogen cycling at ambient oxygen levels well above the hypoxic threshold. Aggregates were produced from the ubiquitous diatom Skeletonema marinoi and the natural microbial community of seawater. Microsensor profiling through the center of sinking aggregates revealed internal anoxia at ambient 40% air saturation (∼100 μmol O2 L-1) and below. Accordingly, anaerobic nitrate turnover inside the aggregates was evident within this range of ambient oxygen levels. In incubations with 15N-labeled nitrate, individual Skeletonema aggregates produced NO2- (up to 10.7 nmol N h-1 per aggregate), N2 (up to 7.1 nmol N h-1), NH4+ (up to 2.0 nmol N h-1), and N2O (up to 0.2 nmol N h-1). Intriguingly, nitrate stored inside the diatom cells served as an additional, internal nitrate source for dinitrogen production, which may partially uncouple anaerobic nitrate turnover by diatom aggregates from direct ambient nitrate supply. Sinking diatom aggregates can contribute directly to fixed-nitrogen loss in low-oxygen environments in the ocean and vastly expand the ocean volume in which anaerobic nitrogen turnover is possible, despite relatively high ambient oxygen levels. Depending on the extent of intracellular nitrate consumption during the sinking process, diatom aggregates may also be involved in the long-distance export of nitrate to the deep ocean. PMID:26903977

  14. Decomposition of Alternative Chirality Amino Acids by Alkaliphilic Anaerobe from Owens Lake, California

    NASA Technical Reports Server (NTRS)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Hoover, Richard B.

    2009-01-01

    The study of alkaliphilic microbial communities from anaerobic sediments of Owens and Mono Lakes in California led to the isolation of a bacterial strain capable of metabolizing amino acids with alternative chirality. According to the phylogenetic analysis, the anaerobic strain BK1 belongs to the genus Tindallia; however, despite the characteristics of other described species of this genus, the strain BK1 was able to grow on D-arginine and Dlysine. Cell morphology of this strain showed straight, motile, non-spore-forming rods with sizes 0.45 x 1.2-3 microns. Physiological characteristics of the strain showed that it is catalase negative, obligately anaerobic, mesophilic, and obligately alkaliphilic. This isolate is unable to grow at pH 7 and requires CO3 (2-) ions for growth. The strain has chemo-heterotrophic metabolism and is able to ferment various proteolysis products and some sugars. It plays the role of a primary anaerobe within the trophic chain of an anaerobic microbial community by the degradation of complex protein molecules to smaller and less energetic molecules. The new isolate requires NaCl for growth, and can grow within the range of 0.5-13 %, with the optimum at 1 % NaCl (w/v). The temperature range for the growth of the new isolate is 12-40 C with optimum at 35 C. The pH range for the growth of strain BK1 occurs between 7.8 and 11.0 with optimum at 9.5. This paper presents detailed physiological characteristics of the novel isolate from Owens Lake, a unique relic ecosystem of Astrobiological significance, and makes an accent on the ability of this strain to utilize L-amino acids.

  15. Initial reactions in the anaerobic oxidation of toluene and m-xylene by denitrifying bacteria.

    PubMed

    Seyfried, B; Glod, G; Schocher, R; Tschech, A; Zeyer, J

    1994-11-01

    Pseudomonas sp. strain T and Pseudomonas sp. strain K172 grow with toluene under denitrifying conditions. We demonstrated that anaerobic degradation of toluene was initiated by direct oxidation of the methyl group. Benzaldehyde and benzoate accumulated sequentially after toluene was added when cell suspensions were incubated at 5 degrees C. Strain T also grows anaerobically with m-xylene, and we demonstrated that degradation was initiated by oxidation of one methyl group. In cell suspensions incubated at 5 degrees C 3-methylbenzaldehyde and 3-methylbenzoate accumulated after m-xylene was added. Toluene- or m-xylene-grown strain T cells were induced to the same extent for oxidation of both hydrocarbons. In addition, the methyl group-oxidizing enzyme system of strain T also catalyzed the oxidation of each isomer of the chloro- and fluorotoluenes to the corresponding halogenated benzoate derivatives. In contrast, strain K172 only oxidized 4-fluorotoluene to 4-fluorobenzoate, probably because of the narrow substrate specificity of the methyl group-oxidizing enzymatic system. During anaerobic growth with toluene strains T and K172 produced two transformation products, benzylsuccinate and benzylfumarate. About 0.5% of the toluene carbon was converted to these products.

  16. Low anaerobic threshold and increased skeletal muscle lactate production in subjects with Huntington's disease.

    PubMed

    Ciammola, Andrea; Sassone, Jenny; Sciacco, Monica; Mencacci, Niccolò E; Ripolone, Michela; Bizzi, Caterina; Colciago, Clarissa; Moggio, Maurizio; Parati, Gianfranco; Silani, Vincenzo; Malfatto, Gabriella

    2011-01-01

    Mitochondrial defects that affect cellular energy metabolism have long been implicated in the etiology of Huntington's disease (HD). Indeed, several studies have found defects in the mitochondrial functions of the central nervous system and peripheral tissues of HD patients. In this study, we investigated the in vivo oxidative metabolism of exercising muscle in HD patients. Ventilatory and cardiometabolic parameters and plasma lactate concentrations were monitored during incremental cardiopulmonary exercise in twenty-five HD subjects and twenty-five healthy subjects. The total exercise capacity was normal in HD subjects but notably the HD patients and presymptomatic mutation carriers had a lower anaerobic threshold than the control subjects. The low anaerobic threshold of HD patients was associated with an increase in the concentration of plasma lactate. We also analyzed in vitro muscular cell cultures and found that HD cells produce more lactate than the cells of healthy subjects. Finally, we analyzed skeletal muscle samples by electron microscopy and we observed striking mitochondrial structural abnormalities in two out of seven HD subjects. Our findings confirm mitochondrial abnormalities in HD patients' skeletal muscle and suggest that the mitochondrial dysfunction is reflected functionally in a low anaerobic threshold and an increased lactate synthesis during intense physical exercise.

  17. FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Heather Akau

    2003-12-01

    The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration and greenhouse emission control. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entails the construction of a 12-acre module that contains a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells are highly instrumented to monitor bioreactor performance. Liquid addition has commenced in the 3.5-acre anaerobic cell and the 6-acre anaerobic cell. Construction of the 2.5-acre aerobic cell and biofilter has been completed. The remaining task to be completed is to test the biofilter prior to operation, which is currently anticipated to begin in January 2004. The current project status and preliminary monitoring results are summarized in this report.

  18. FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Heather Akau

    2002-04-01

    The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches while providing superior environmental protection. The overall objective is to manage landfill solid waste for rapid waste decomposition, maximum landfill gas generation and capture, and minimum long-term environmental consequences. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entails the construction of a 12-acre module that contains a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells are highly instrumented to monitor bioreactor performance. Construction is complete on the 3.5 acre anaerobic cell and liquid addition has commenced. Construction of the 2.5 acre aerobic cell is nearly complete with only the blower station and biofilter remaining. Waste placement and instrumentation installation is ongoing in the west-side 6-acre anaerobic cell. The current project status and preliminary monitoring results are summarized in this report.

  19. FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Heather Akau

    2003-08-01

    The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration and greenhouse emission control. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entails the construction of a 12-acre module that contains a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells are highly instrumented to monitor bioreactor performance. Liquid addition has commenced in the 3.5-acre anaerobic cell and the 6-acre anaerobic cell. Construction of the 2.5-acre aerobic cell is nearly complete with only the biofilter remaining and is scheduled to be complete by the end of August 2003. The current project status and preliminary monitoring results are summarized in this report.

  20. FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Heather Akau

    2002-08-01

    The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration and greenhouse emission control. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entails the construction of a 12-acre module that contains a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells are highly instrumented to monitor bioreactor performance. Construction is complete on the 3.5-acre anaerobic cell and liquid addition has commenced. Construction of the 2.5 acre aerobic cell is nearly complete with only the blower station and biofilter remaining. Waste placement and instrumentation installation is ongoing in the west-side 6-acre anaerobic cell. The current project status and preliminary monitoring results are summarized in this report.

  1. FULL SCALE BIOREACTOR LANDFILL FOR CARBON SEQUESTRATION AND GREENHOUSE EMISSION CONTROL

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Heather Akau

    2003-05-01

    The Yolo County Department of Planning and Public Works is constructing a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective is to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration and greenhouse emission control. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entails the construction of a 12-acre module that contains a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells are highly instrumented to monitor bioreactor performance. Construction is complete on the 3.5-acre anaerobic cell and liquid addition has commenced. Construction of the 2.5-acre aerobic cell is nearly complete with only the biofilter remaining and construction of the west-side 6-acre anaerobic cell is nearly complete with only the liquid addition system remaining. The current project status and preliminary monitoring results are summarized in this report.

  2. Full Scale Bioreactor Landfill for Carbon Sequestration and Greenhouse Emission Control

    SciTech Connect

    Ramin Yazdani; Jeff Kieffer; Kathy Sananikone; Don Augenstein

    2005-03-30

    The Yolo County Department of Planning and Public Works constructed a full-scale bioreactor landfill as a part of the Environmental Protection Agency's (EPA) Project XL program to develop innovative approaches for carbon sequestration and greenhouse emission control. The overall objective was to manage landfill solid waste for rapid waste decomposition and maximum landfill gas generation and capture for carbon sequestration and greenhouse emission control. Waste decomposition is accelerated by improving conditions for either the aerobic or anaerobic biological processes and involves circulating controlled quantities of liquid (leachate, groundwater, gray water, etc.), and, in the aerobic process, large volumes of air. The first phase of the project entailed the construction of a 12-acre module that contained a 6-acre anaerobic cell, a 3.5-acre anaerobic cell, and a 2.5-acre aerobic cell at the Yolo County Central Landfill near Davis, California. The cells were highly instrumented to monitor bioreactor performance. Liquid addition commenced in the 3.5-acre anaerobic cell and the 6-acre anaerobic cell. Construction of the 2.5-acre aerobic cell and biofilter has been completed. The current project status and preliminary monitoring results are summarized in this report.

  3. Atmospheric vs. anaerobic processing of metabolome samples for the metabolite profiling of a strict anaerobic bacterium, Clostridium acetobutylicum.

    PubMed

    Lee, Sang-Hyun; Kim, Sooah; Kwon, Min-A; Jung, Young Hoon; Shin, Yong-An; Kim, Kyoung Heon

    2014-12-01

    Well-established metabolome sample preparation is a prerequisite for reliable metabolomic data. For metabolome sampling of a Gram-positive strict anaerobe, Clostridium acetobutylicum, fast filtration and metabolite extraction with acetonitrile/methanol/water (2:2:1, v/v) at -20°C under anaerobic conditions has been commonly used. This anaerobic metabolite processing method is laborious and time-consuming since it is conducted in an anaerobic chamber. Also, there have not been any systematic method evaluation and development of metabolome sample preparation for strict anaerobes and Gram-positive bacteria. In this study, metabolome sampling and extraction methods were rigorously evaluated and optimized for C. acetobutylicum by using gas chromatography/time-of-flight mass spectrometry-based metabolomics, in which a total of 116 metabolites were identified. When comparing the atmospheric (i.e., in air) and anaerobic (i.e., in an anaerobic chamber) processing of metabolome sample preparation, there was no significant difference in the quality and quantity of the metabolomic data. For metabolite extraction, pure methanol at -20°C was a better solvent than acetonitrile/methanol/water (2:2:1, v/v/v) at -20°C that is frequently used for C. acetobutylicum, and metabolite profiles were significantly different depending on extraction solvents. This is the first evaluation of metabolite sample preparation under aerobic processing conditions for an anaerobe. This method could be applied conveniently, efficiently, and reliably to metabolome analysis for strict anaerobes in air.

  4. Can anaerobes be acid fast? A novel, clinically relevant acid fast anaerobe

    PubMed Central

    Jump, Robin; Canaday, David H.; Wnek, Maria D.; SenGupta, Dhruba J.; McQuiston, John R.; Bell, Melissa

    2016-01-01

    Introduction: Anaerobic acid fast bacilli (AFB) have not been previously reported in clinical microbiology. This is the second case report of a novel anaerobic AFB causing disease in humans. Case presentation: An anaerobic AFB was isolated from an abdominal wall abscess in a 64–year-old Caucasian diabetic male, who underwent distal pancreatectomy and splenectomy for resection of a pancreatic neuroendocrine tumour. The isolated bacteria were gram-variable and acid-fast, consisting of small irregular rods. The 16S rRNA gene sequence analysis showed that the isolate is a novel organism described in the literature only once before. The organism was studied at the CDC (Centers for Disease Control and Prevention) by the same group that worked with the isolates from the previous report; their findings suggest that the strain belongs to the suborder Corynebacterineae. Conclusion: This is the fifth reported case of an anaerobic AFB involved in clinical disease; its microbiological features and 16S RNA sequence are identical to previously reported cases. Clinical disease with this organism seems to be associated with recent history of surgery and abscess formation in deep soft tissues. Acquisition from surgical material is uncertain but seems unlikely. PMID:28348766

  5. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

    SciTech Connect

    Mendes, Carlos Esquerre, Karla Matos Queiroz, Luciano

    2015-01-15

    Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

  6. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    PubMed

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

  7. The challenges of anaerobic digestion and the role of biochar in optimizing anaerobic digestion.

    PubMed

    Fagbohungbe, Michael O; Herbert, Ben M J; Hurst, Lois; Ibeto, Cynthia N; Li, Hong; Usmani, Shams Q; Semple, Kirk T

    2017-03-01

    Biochar, like most other adsorbents, is a carbonaceous material, which is formed from the combustion of plant materials, in low-zero oxygen conditions and results in a material, which has the capacity to sorb chemicals onto its surfaces. Currently, research is being carried out to investigate the relevance of biochar in improving the soil ecosystem, digestate quality and most recently the anaerobic digestion process. Anaerobic digestion (AD) of organic substrates provides both a sustainable source of energy and a digestate with the potential to enhance plant growth and soil health. In order to ensure that these benefits are realised, the anaerobic digestion system must be optimized for process stability and high nutrient retention capacity in the digestate produced. Substrate-induced inhibition is a major issue, which can disrupt the stable functioning of the AD system reducing microbial breakdown of the organic waste and formation of methane, which in turn reduces energy output. Likewise, the spreading of digestate on land can often result in nutrient loss, surface runoff and leaching. This review will examine substrate inhibition and their impact on anaerobic digestion, nutrient leaching and their environmental implications, the properties and functionality of biochar material in counteracting these challenges.

  8. [Distribution and removal of anaerobic antibiotic resistant bacteria during mesophilic anaerobic digestion of sewage sludge].

    PubMed

    Tong, Juan; Wang, Yuan-Yue; Wei Yuan, Song

    2014-10-01

    Sewage sludge is one of the major sources that releasing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) into the environment since it contains large amount of ARB, but there is little information about the fate of the anaerobic ARB in the anaerobic digestion of sewage sludge. Therefore, the distribution, removal and seasonal changes of tetracycline and β-lactam antibiotics resistant bacteria in the mesophilic egg-shaped digesters of a municipal wastewater treatment plant were investigated for one year in this study. Results showed that there were higher amounts of ARB and higher resistance rate of β-lactam antibiotics than that of tetracycline antibiotics in the sewage sludge. All ARB could be significantly reduced during the mesophilic anaerobic digestion process by 1.48-1.64 log unit (P < 0.05). Notably, the ampicillin and cephalothin resistance rates were significantly increased after anaerobic digestion by 12.0% and 14.3%, respectively (P < 0.05). The distribution of ARB in the sewage sludge had seasonal change characteristics. Except for chlorotetracycline resistant bacteria, there were more ARB in the sewage sludge in cold season than in warm season (P < 0.05).

  9. Experimental evidence for growth advantage and metabolic shift stimulated by photophosphorylation of proteorhodopsin expressed in Escherichia coli at anaerobic condition.

    PubMed

    Wang, Ying; Li, Yan; Xu, Tuan; Shi, Zhenyu; Wu, Qiong

    2015-05-01

    Since solar light energy is the source of all renewable biological energy, the direct usage of light energy by bacterial cell factory has been a very attractive concept, especially using light energy to promote anaerobic fermentation growth and even recycle low-energy carbon source when energy is the limiting factor. Proteorhodopsin(PR), a light-driven proton pump proven to couple with ATP synthesis when expressed heterogeneously, is an interesting and simple option to enable light usage in engineered strains. However, although it was reported to influence fermentation in some cases, heterogeneous proteorhodopsin expression was never shown to support growth advantage or cause metabolic shift by photophosphorylation so far. Hereby, we presented the first experimental evidence that heterogeneously expressed proteorhodopsin can provide growth advantage and cause ATP-dependent metabolism shift of acetate and lactate changes in Escherichia coli at anaerobic condition. Those discoveries suggest further application potential of PR in anaerobic fermentation where energy is a limiting factor.

  10. Horse manure as feedstock for anaerobic digestion.

    PubMed

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible.

  11. Hybrid modelling of anaerobic wastewater treatment processes.

    PubMed

    Karama, A; Bernard, O; Genovesi, A; Dochain, D; Benhammou, A; Steyer, J P

    2001-01-01

    This paper presents a hybrid approach for the modelling of an anaerobic digestion process. The hybrid model combines a feed-forward network, describing the bacterial kinetics, and the a priori knowledge based on the mass balances of the process components. We have considered an architecture which incorporates the neural network as a static model of unmeasured process parameters (kinetic growth rate) and an integrator for the dynamic representation of the process using a set of dynamic differential equations. The paper contains a description of the neural network component training procedure. The performance of this approach is illustrated with experimental data.

  12. Muscle deoxygenation in aerobic and anaerobic exercise.

    PubMed

    Nioka, S; Moser, D; Lech, G; Evengelisti, M; Verde, T; Chance, B; Kuno, S

    1998-01-01

    It has been generally accepted that the use of oxygen is a major contributor of ATP synthesis in endurance exercise but not in short sprints. In anaerobic exercise, muscle energy is thought to be initially supported by the PCr-ATP system followed by glycolysis, not through mitochondrial oxidative phosphorylation. However, in real exercise practice, we do not know how much of this notion is true when an athlete approaches his/her maximal capacity of aerobic and anaerobic exercise, such as during a graded VO2max test. This study investigates the use of oxygen in aerobic and anaerobic exercise by monitoring oxygen concentration of the vastus lateralis muscle at maximum intensity using Near Infra-red Spectroscopy (NIRS). We tested 14 sprinters from the University of Penn track team, whose competitive events are high jump, pole vault, 100 m, 200 m, 400 m, and 800 m. The Wingate anaerobic power test was performed on a cycle ergometer with 10% body weight resistance for 30 seconds. To compare oxygenation during aerobic exercise, a steady-state VO2max test with a cycle ergometer was used with 25 watt increments every 2 min. until exhaustion. Results showed that in the Wingate test, total power reached 774 +/- 86 watt, about 3 times greater than that in the VO2max test (270 +/- 43 watt). In the Wingate test, the deoxygenation reached approximately 80% of the established maximum value, while in the VO2max test resulted in approximately 36% deoxygenation. There was no delay in onset of deoxygenation in the Wingate test, while in the VO2max test, deoxygenation did not occur under low intensity work. The results indicate that oxygen was used from the beginning of sprint test, suggesting that the mitochondrial ATP synthesis was triggered after a surprisingly brief exercise duration. One explanation is that prior warm-up (unloaded exercise) was enough to provide the mitochondrial substrates; ADP and Pi to activate oxidative phosphorylation by the type II a and type I myocytes. In

  13. Improvement of anaerobic digestion of sludge.

    PubMed

    Dohányos, M; Zábranská, J; Kutil, J; Jenícek, P

    2004-01-01

    Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of the process conditions, pretreatment of input sludge and increase of process temperature is frequently used. The thermophilic process brings a higher solids reduction and biogas production, a high resistance to foaming, no problems with odour, better pathogens destruction and an improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in a lysate centrifuge was proved to cause increase of biogas production in full-scale conditions. The rapid thermal conditioning of digested sludge is an acceptable method of particulate matter disintegration and solubilization.

  14. Anaerobic digestion of municipal solid waste

    SciTech Connect

    Dasgupta, A.; Nemerow, N.L.; Farooq, S.; Daly, E.L.Jr.; Sengupta, S.; Gerrish, H.P.; Wong, K.F.

    1981-01-01

    Filtrate from an anaerobic municipal waste digestion plant at Pompano Beach, Florida, has BOD, COD, and total organic C contents of 1075, 6855, and 1655 mg/L, respectively. The treatment does not inactivate total coliforms; that of the digester slurry and filtrate are 2.3 X 10 to the power of 6 and 1.7 X 10 to the power of 6/100 mL, respectively. The average concentrations of Cr, Cu, Mn, Fe, Ni, and Zn in the filtrate are 0.48, 1.29, 7.29, 32, 0.35, and 11 mg/L, respectively. The filtrate requires treatment prior to discharge.

  15. Anaerobic wastewater treatment of concentrated sewage using a two-stage upflow anaerobic sludge blanket- anaerobic filter system.

    PubMed

    Halalsheh, Maha M; Abu Rumman, Zainab M; Field, Jim A

    2010-01-01

    A two-stage pilot-scale upflow anaerobic sludge blanket - anaerobic filter (UASB-AF) reactors system treating concentrated domestic sewage was operated at 23 degrees C and at hydraulic retention times (HRT) of 15 and 4 h, respectively. Excess sludge from the downstream AF stage was returned to the upstream UASB reactor. The aim was to obtain higher sludge retention time (SRT) in the UASB reactor for better methanization of suspended COD. The UASB-AF system removed 55% and 65% of the total COD (COD(tot)) and suspended COD (COD(ss)), respectively. The calculated SRT in the UASB reactor ranged from 20-35 days. The AF reactor removed the washed out sludge from the first stage reactor with average COD(ss) removal efficiency of 55%. The volatile fatty acids concentration in the effluent of the AF was 39 mg COD/L compared with 78 mg COD/L measured for the influent. The slightly higher COD(tot) removal efficiency obtained in this study compared with a single stage UASB reactor was achieved at 17% reduction in the total volume.

  16. Catalase (KatA) Plays a Role in Protection against Anaerobic Nitric Oxide in Pseudomonas aeruginosa

    PubMed Central

    Su, Shengchang; Panmanee, Warunya; Wilson, Jeffrey J.; Mahtani, Harry K.; Li, Qian; VanderWielen, Bradley D.; Makris, Thomas M.; Rogers, Melanie; McDaniel, Cameron; Lipscomb, John D.; Irvin, Randall T.; Schurr, Michael J.; Lancaster, Jack R.; Kovall, Rhett A.; Hassett, Daniel J.

    2014-01-01

    Pseudomonas aeruginosa (PA) is a common bacterial pathogen, responsible for a high incidence of nosocomial and respiratory infections. KatA is the major catalase of PA that detoxifies hydrogen peroxide (H2O2), a reactive oxygen intermediate generated during aerobic respiration. Paradoxically, PA displays elevated KatA activity under anaerobic growth conditions where the substrate of KatA, H2O2, is not produced. The aim of the present study is to elucidate the mechanism underlying this phenomenon and define the role of KatA in PA during anaerobiosis using genetic, biochemical and biophysical approaches. We demonstrated that anaerobic wild-type PAO1 cells yielded higher levels of katA transcription and expression than aerobic cells, whereas a nitrite reductase mutant ΔnirS produced ∼50% the KatA activity of PAO1, suggesting that a basal NO level was required for the increased KatA activity. We also found that transcription of the katA gene was controlled, in part, by the master anaerobic regulator, ANR. A ΔkatA mutant and a mucoid mucA22 ΔkatA bacteria demonstrated increased sensitivity to acidified nitrite (an NO generator) in anaerobic planktonic and biofilm cultures. EPR spectra of anaerobic bacteria showed that levels of dinitrosyl iron complexes (DNIC), indicators of NO stress, were increased significantly in the ΔkatA mutant, and dramatically in a ΔnorCB mutant compared to basal levels of DNIC in PAO1 and ΔnirS mutant. Expression of KatA dramatically reduced the DNIC levels in ΔnorCB mutant. We further revealed direct NO-KatA interactions in vitro using EPR, optical spectroscopy and X-ray crystallography. KatA has a 5-coordinate high spin ferric heme that binds NO without prior reduction of the heme iron (Kd ∼6 μM). Collectively, we conclude that KatA is expressed to protect PA against NO generated during anaerobic respiration. We proposed that such protective effects of KatA may involve buffering of free NO when potentially toxic concentrations of

  17. Catalase (KatA) plays a role in protection against anaerobic nitric oxide in Pseudomonas aeruginosa.

    PubMed

    Su, Shengchang; Panmanee, Warunya; Wilson, Jeffrey J; Mahtani, Harry K; Li, Qian; Vanderwielen, Bradley D; Makris, Thomas M; Rogers, Melanie; McDaniel, Cameron; Lipscomb, John D; Irvin, Randall T; Schurr, Michael J; Lancaster, Jack R; Kovall, Rhett A; Hassett, Daniel J

    2014-01-01

    Pseudomonas aeruginosa (PA) is a common bacterial pathogen, responsible for a high incidence of nosocomial and respiratory infections. KatA is the major catalase of PA that detoxifies hydrogen peroxide (H2O2), a reactive oxygen intermediate generated during aerobic respiration. Paradoxically, PA displays elevated KatA activity under anaerobic growth conditions where the substrate of KatA, H2O2, is not produced. The aim of the present study is to elucidate the mechanism underlying this phenomenon and define the role of KatA in PA during anaerobiosis using genetic, biochemical and biophysical approaches. We demonstrated that anaerobic wild-type PAO1 cells yielded higher levels of katA transcription and expression than aerobic cells, whereas a nitrite reductase mutant ΔnirS produced ∼50% the KatA activity of PAO1, suggesting that a basal NO level was required for the increased KatA activity. We also found that transcription of the katA gene was controlled, in part, by the master anaerobic regulator, ANR. A ΔkatA mutant and a mucoid mucA22 ΔkatA bacteria demonstrated increased sensitivity to acidified nitrite (an NO generator) in anaerobic planktonic and biofilm cultures. EPR spectra of anaerobic bacteria showed that levels of dinitrosyl iron complexes (DNIC), indicators of NO stress, were increased significantly in the ΔkatA mutant, and dramatically in a ΔnorCB mutant compared to basal levels of DNIC in PAO1 and ΔnirS mutant. Expression of KatA dramatically reduced the DNIC levels in ΔnorCB mutant. We further revealed direct NO-KatA interactions in vitro using EPR, optical spectroscopy and X-ray crystallography. KatA has a 5-coordinate high spin ferric heme that binds NO without prior reduction of the heme iron (Kd ∼6 μM). Collectively, we conclude that KatA is expressed to protect PA against NO generated during anaerobic respiration. We proposed that such protective effects of KatA may involve buffering of free NO when potentially toxic concentrations of

  18. Anaerobic soil disinfestation and soil borne pest management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD; also referred to as Biological Soil Disinfestation (BSD)) is a pre-plant soil treatment method developed to control plant disease and manage yield decline in many crop production systems. The practice involves induction of anaerobic soil conditions by increasing m...

  19. Molecular AND logic gate based on bacterial anaerobic respiration.

    PubMed

    Arugula, Mary Anitha; Shroff, Namita; Katz, Evgeny; He, Zhen

    2012-10-21

    Enzyme coding genes that integrate information for anaerobic respiration in Shewanella oneidensis MR-1 were used as input for constructing an AND logic gate. The absence of one or both genes inhibited electrochemically-controlled anaerobic respiration, while wild type bacteria were capable of accepting electrons from an electrode for DMSO reduction.

  20. Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

    PubMed Central

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F.; Valderrama, J. Andrés; Barragán, María J. L.; García, José Luis; Díaz, Eduardo

    2009-01-01

    Summary: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach. PMID:19258534

  1. Balancing hygienization and anaerobic digestion of raw sewage sludge.

    PubMed

    Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

    2012-12-01

    The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery.

  2. Growth of the facultative anaerobes from Antarctica, Alaska, and Patagonia at low temperatures

    NASA Astrophysics Data System (ADS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-11-01

    Psychrotolerance, as an adaptation for surviving in extreme environments, is widespread among mesophilic microorganisms. Physico-chemical factors such as pressure, red-ox potential, pH and salinity could significantly alter the features of ecosystems by providing liquid water at subzero temperatures. Furthermore, organisms can respond to temperature changes by several known mechanisms, including changing the conformation capacities of constitutional proteins or by the synthesis of mucopolysaccharides around the cell wall and membrane. Such protective mechanisms make it possible for cells to not only passively survive low temperatures in a state of anabiosis, but also to be capable of actively metabolizing substrates and reproducing normally. The physiological and biochemical characteristics of the species, as well as genetics, could be remarkably changed due to adaptation and surviving in extreme environments. The cold shock genes of some of the studied strains of psychrotolerant facultative anaerobes were reported previously. In this paper we present experimental data for psychrotolerant, non spore-forming, facultative anaerobes isolated from geographically different cold regions of our planet. We show the growth response on changing from anaerobic conditions to aerobic with cultivation at low temperatures.

  3. Oxygen Effect on the Low Temperature Tolerance of Facultative Anaerobes from Antarctica, Alaska, and Patagonia

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    Psychrotolerance as an adaptation to survival in extreme environments is widespread among many of the mesophilic microorganisms. Red-ox potential, pH and salinity could significantly alter the features of ecosystems by providing liquid water at subzero temperatures. Furthermore, organisms can respond to temperature changes by several known mechanisms, including changing the conformation capacities of constitutional proteins or by the synthesis of mucopolysaccharides around the cell wall and membrane. Such protective mechanisms make it possible for cells to not only passively survive low-temperature in a state of anabiosis, but also to be capable of actively metabolizing substrates and reproducing normally. The physiological and biochemical characteristics of species as well as genetics could be remarkably changed due to -on and surviving m extreme environments. The cold shock genes for some of the studied strains of psychrotolerant facultative anaerobes already were published In this paper we present experimental data for psychrotolerant facultative anaerobes isolated from geographically different cold regions of our planet. We show the growth response on the changing of anaerobic conditions to aerobic with cultivation at subzero temperatures.

  4. Growth of the Facultative Anaerobes from Antarctica, Alaska, and Patagonia at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    Psychotolerance, as an adaptation for surviving in extreme environments, is widespread among mesophilic microorganisms. Physico-chemical factors such as pressure, red-ox potential, pH and salinity could significantly alter the features of ecosystems by providing liquid water at subzero temperatures. Furthermore, organisms can respond to temperature changes by several known mechanisms, including changing the conformation capacities of constitutional proteins or by the synthesis of mucopolysaccharides around the cell wall and membrane. Such protective mechanisms make it possible for cells to not only passively survive low temperatures in a state of anabiosis, but also to be capable of actively metabolizing substrates and reproducing normally. The physiological and biochemical characteristics of the species, as well as genetics, could be remarkably changed due to adaptation and surviving in extreme environments. The cold shock genes of some of the studied strains of psychotolerant facultative anaerobes were reported previously. In this paper we present experimental data for psychotolerant, non spore-forming, facultative anaerobes isolated from geographically different cold regions of our planet. We show the growth response on changing from anaerobic conditions to aerobic with cultivation at low temperatures.

  5. Effect of anaerobic promoters on the microaerobic production of polyhydroxybutyrate (PHB) in recombinant Escherichia coli.

    PubMed

    Wei, Xiao-Xing; Shi, Zhen-Yu; Yuan, Mei-Qing; Chen, Guo-Qiang

    2009-03-01

    Nine anaerobic promoters were cloned and constructed upstream of PHB synthesis genes phbCAB from Ralstonia eutropha for the micro- or anaerobic PHB production in recombinant Escherichia coli. Among the promoters, the one for alcohol dehydrogenase (PadhE) was found most effective. Recombinant E. coli JM 109 (pWCY09) harboring PadhE and phbCAB achieved a 48% PHB accumulation in the cell dry weight after 48 h of static culture compared with only 30% PHB production under its native promoter. Sixty-seven percent PHB was produced in the dry weight (CDW) of an acetate pathway deleted (Deltapta deletion) E. coli JW2294 harboring the vector pWCY09. In a batch process conducted in a 5.5-l NBS fermentor containing 3 l glucose LB medium, E. coli JW2294 (pWCY09) grew to 7.8 g/l CDW containing 64% PHB after 24 h of microaerobic incubation. In addition, molecular weight of PHB was observed to be much higher under microaerobic culture conditions. The high activity of PadhE appeared to be the reason for improved micro- or anaerobic cell growth and PHB production while high molecular weight contributed to the static culture condition.

  6. Anaerobic Mercury Methylation and Demethylation by Geobacter bemidjiensis Bem

    SciTech Connect

    Lu, Xia; Liu, Yurong; Johs, Alexander; Zhao, Linduo; Wang, Tieshan; Yang, Ziming; Lin, Hui; Elias, Dwayne A.; Pierce, Eric M.; Liang, Liyuan; Barkay, Tamar; Gu, Baohua

    2016-03-28

    Two competing processes controlling the net production and bioaccumulation of neurotoxic methylmercury (MeHg) in natural ecosystems are microbial methylation and demethylation. Though mercury (Hg) methylation by anaerobic microorganisms and demethylation by aerobic Hg-resistant bacteria have both been extensively studied, little attention has been given to MeHg degradation by anaerobic bacteria, particularly the iron-reducing bacterium Geobacter bemidjensis Bem. Here we report, for the first time, that the strain G. bemidjensis Bem can methylate inorganic Hg and degrade MeHg concurrently under anoxic conditions. Our results suggest that G. bemidjensis cells utilize a reductive demethylation pathway to degrade MeHg, with elemental Hg(0) as the major reaction product, possibly due to the presence of homologs encoding both organo-mercurial lyase (MerB) and mercuric reductase (MerA) in this organism. In addition, the cells can mediate multiple reactions including Hg/MeHg sorption, Hg reduction and oxidation, resulting in both time and concentration dependent Hg species transformations. Moderate concentrations (10 500 M) of Hg-binding ligands such as cysteine enhance Hg(II) methylation but inhibit MeHg degradation. These findings indicate a cycle of methylation and demethylation among anaerobic bacteria and suggest that mer-mediated demethylation may play a role in the net balance of MeHg production in anoxic water and sediments.

  7. Adsorption and decolorization kinetics of methyl orange by anaerobic sludge.

    PubMed

    Yu, Lei; Li, Wen-Wei; Lam, Michael Hon-Wah; Yu, Han-Qing

    2011-05-01

    Adsorption and decolorization kinetics of methyl orange (MO) by anaerobic sludge in anaerobic sequencing batch reactors were investigated. The anaerobic sludge was found to have a saturated adsorption capacity of 36 ± 1 mg g MLSS(-1) to MO. UV/visible spectrophotometer and high-performance liquid chromatography analytical results indicated that the MO adsorption and decolorization occurred simultaneously in this system. This process at various substrate concentrations could be well simulated using a modified two-stage model with apparent pseudo first-order kinetics. Furthermore, a noncompetitive inhibition kinetic model was also developed to describe the MO decolorization process at high NaCl concentrations, and an inhibition constant of 3.67 g NaCl l(-1) was estimated. This study offers an insight into the adsorption and decolorization processes of azo dyes by anaerobic sludge and provides a better understanding of the anaerobic dye decolorization mechanisms.

  8. Performance of an anaerobic membrane bioreactor for pharmaceutical wastewater treatment.

    PubMed

    Svojitka, Jan; Dvořák, Lukáš; Studer, Martin; Straub, Jürg Oliver; Frömelt, Heinz; Wintgens, Thomas

    2017-04-01

    Anaerobic treatment of wastewater and waste organic solvents originating from the pharmaceutical and chemical industries was tested in a pilot anaerobic membrane bioreactor, which was operated for 580days under different operational conditions. The goal was to test the long-term treatment efficiency and identify inhibitory factors. The highest COD removal of up to 97% was observed when the influent concentration was increased by the addition of methanol (up to 25gL(-1) as COD). Varying and generally lower COD removal efficiency (around 78%) was observed when the anaerobic membrane bioreactor was operated with incoming pharmaceutical wastewater as sole carbon source. The addition of waste organic solvents (>2.5gL(-1) as COD) to the influent led to low COD removal efficiency or even to the breakdown of anaerobic digestion. Changes in the anaerobic population (e.g., proliferation of the genus Methanosarcina) resulting from the composition of influent were observed.

  9. Absence of microbial mineralization of lignin in anaerobic enrichment cultures.

    PubMed Central

    Odier, E; Monties, B

    1983-01-01

    The existence of anaerobic biodegradation of lignin was examined in mixed microflora. Egyptian soil samples, in which rapid mineralization of organic matter takes place in the presence of an important anaerobic microflora, were used to obtain the anaerobic enrichment cultures for this study. Specifically, 14CO2 or [14C]lignin wood was used to investigate the release of labeled gaseous or soluble degradation products of lignin in microbial cultures. No conversion of 14C-labeled lignin to 14CO2 or 14CH4 was observed after 6 months of incubation at 30 degrees C in anaerobic conditions with or without NO3-. A small increase in soluble radioactivity was observed in certain cultures, but it could not be related to the release of catabolic products during the anaerobic biodegradation of lignin. PMID:6639020

  10. Anaerobic biodegradation of hexazinone in four sediments.

    PubMed

    Wang, Huili; Xu, Shuxia; Tan, Chengxia; Wang, Xuedong

    2009-05-30

    Anaerobic biodegradation of hexazinone was investigated in four sediments (L1, L2, Y1 and Y2). Results showed that the L2 sediment had the highest biodegradation potential among four sediments. However, the Y1 and Y2 sediments had no capacity to biodegrade hexazinone. Sediments with rich total organic carbon, long-term contamination history by hexazinone and neutral pH may have a high biodegradation potential because the former two factors can induce the growth of microorganisms responsible for biodegradation and the third factor can offer suitable conditions for biodegradation. The addition of sulfate or nitrate as electron acceptors enhanced hexazinone degradation. As expected, the addition of electron donors (lactate, acetate or pyruvate) substantially inhibited the degradation. In natural environmental conditions, the effect of intermediate A [3-(4-hydroxycyclohexyl)-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)dione] on anaerobic hexazinone degradation was negligible because of its low level.

  11. Electrolysis-enhanced anaerobic digestion of wastewater.

    PubMed

    Tartakovsky, B; Mehta, P; Bourque, J-S; Guiot, S R

    2011-05-01

    This study demonstrates enhanced methane production from wastewater in laboratory-scale anaerobic reactors equipped with electrodes for water electrolysis. The electrodes were installed in the reactor sludge bed and a voltage of 2.8-3.5 V was applied resulting in a continuous supply of oxygen and hydrogen. The oxygen created micro-aerobic conditions, which facilitated hydrolysis of synthetic wastewater and reduced the release of hydrogen sulfide to the biogas. A portion of the hydrogen produced electrolytically escaped to the biogas improving its combustion properties, while another part was converted to methane by hydrogenotrophic methanogens, increasing the net methane production. The presence of oxygen in the biogas was minimized by limiting the applied voltage. At a volumetric energy consumption of 0.2-0.3 Wh/L(R), successful treatment of both low and high strength synthetic wastewaters was demonstrated. Methane production was increased by 10-25% and reactor stability was improved in comparison to a conventional anaerobic reactor.

  12. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  13. Anaerobic Toxicity of Cationic Silver Nanoparticles | Science ...

    EPA Pesticide Factsheets

    The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged polyvinylpyrrolidone coated AgNPs (PVP-AgNps) and (3) positively charged branched polyethyleneimine coated AgNPs (BPEI-AgNPs). The AgNPs investigated in this experiment were similar in size (10-15 nm), spherical in shape, but varied in surface charge which ranged from highly negative to highly positive. While, at AgNPs concentrations lower than 5 mg L-1, the anaerobic decomposition process was not influenced by the presence of the nanoparticles, there was an observed impact on the diversity of the microbial community. At elevated concentrations (100 mg L-1 as silver), only the cationic BPEI-AgNPs demonstrated toxicity similar in magnitude to that of Ag+. Both citrate and PVP-AgNPs did not exhibit toxicity at the 100 mg L-1 as measured by biogas evolution. These findings further indicate the varying modes of action for nanoparticle toxicity and represent one of the few studies that evaluate end-of-life management concerns with regards to the increasing use of nanomaterials in our everyday life. These findings also highlight some of the concerns with a one size fits all approach to the evaluation of environmental health and safety concerns associated with the use of nanoparticles. The current

  14. Effects of shearing on biogas production and microbial community structure during anaerobic digestion with recuperative thickening.

    PubMed

    Yang, Shufan; Phan, Hop V; Bustamante, Heriberto; Guo, Wenshan; Ngo, Hao H; Nghiem, Long D

    2017-03-12

    Recuperative thickening can intensify anaerobic digestion to produce more biogas and potentially reduce biosolids odour. This study elucidates the effects of sludge shearing during the thickening process on the microbial community structure and its effect on biogas production. Medium shearing resulted in approximately 15% increase in biogas production. By contrast, excessive or high shearing led to a marked decrease in biogas production, possibly due to sludge disintegration and cell lysis. Microbial analysis using 16S rRNA gene amplicon sequencing showed that medium shearing increased the evenness and diversity of the microbial community in the anaerobic digester, which is consistent with the observed improved biogas production. By contrast, microbial diversity decreased under either excessive shearing or high shearing condition. In good agreement with the observed decrease in biogas production, the abundance of Bacteroidales and Syntrophobaterales (which are responsible for hydrolysis and acetogenesis) decreased due to high shearing during recuperative thickening.

  15. Anaerobic taurine oxidation: a novel reaction by a nitrate-reducing Alcaligenes sp.

    PubMed

    Denger, K; Laue, H; Cook, A M

    1997-06-01

    Enrichment cultures were prepared under strictly anoxic conditions in medium representing fresh water and containing an organosulfonate as electron donor and carbon source, and nitrate as electron acceptor. The inoculum was from the anaerobic digestor of two communal sewage works. The natural organosulfonates 2-aminoethanesulfonate (taurine), DL-2-amino-3-sulfopropionate (cysteate) and 2-hydroxyethanesulfonate (isethionate) all gave positive enrichments, whereas unsubstituted alkanesulfonates, such as methanesulfonate and arenesulfonates, gave no enrichment. Two representative enrichments were used to obtain pure cultures, and strains NKNTAU (utilizing taurine) and NKNIS (utilizing isethionate) were isolated. Strain NKNTAU was examined in detail. Out of 18 tested organosulfonates, it utilized only one, taurine, and was identified as a novel Alcaligenes sp., a facultatively anaerobic bacterium. Carbon from taurine was converted to cell material and carbon dioxide. The amino group was released as ammonium ion and the sulfonate moiety was recovered as sulfate. Nitrate was reduced to nitrogen gas.

  16. Real-Time Molecular Monitoring of Chemical Environment in ObligateAnaerobes during Oxygen Adaptive Response

    SciTech Connect

    Holman, Hoi-Ying N.; Wozei, Eleanor; Lin, Zhang; Comolli, Luis R.; Ball, David. A.; Borglin, Sharon; Fields, Matthew W.; Hazen, Terry C.; Downing, Kenneth H.

    2009-02-25

    Determining the transient chemical properties of the intracellular environment canelucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms which enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier Transform Infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bonding in their cellular water. We observed a sequence of wellorchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses.

  17. Clostridium aldrichii sp. nov., a cellulolytic mesophile inhabiting a wood-fermenting anaerobic digester.

    PubMed

    Yang, J C; Chynoweth, D P; Williams, D S; Li, A

    1990-07-01

    An anaerobic, mesophilic, spore-forming, cellulolytic bacterium was repeatedly isolated from a wood-fermenting anaerobic digester. Cells of this organism were gram-positive rods, motile with a bundle of polar flagella, and formed subterminal oblong spores. The colonies in agar had an irregular shape with many platelike structures and were greyish white. Cellulose, xylan, and cellobiose served as substrates for growth. Acetate, propionate, butyrate, isobutyrate, isovalerate, lactate, succinate, H2, and CO2 were products of cellobiose fermentation. The optimal temperature and pH for growth were 35 degrees C and 7, respectively. The DNA composition was 40 mol% G + C. The name Clostridium aldrichii sp. nov. is proposed. The type strain is P-1 (= OGI 112, = ATCC 49358).

  18. Continuous Drip Flow System to Develop Biofilm of E. faecalis under Anaerobic Conditions

    PubMed Central

    Gonzalez, Ana Maria; Corpus, Erika; Silva-Herzog, Daniel; Aragon-Piña, Antonio; Cohenca, Nestor

    2014-01-01

    Purpose. To evaluate a structurally mature E. faecalis biofilm developed under anaerobic/dynamic conditions in an in vitro system. Methods. An experimental device was developed using a continuous drip flow system designed to develop biofilm under anaerobic conditions. The inoculum was replaced every 24 hours with a fresh growth medium for up to 10 days to feed the system. Gram staining was done every 24 hours to control the microorganism purity. Biofilms developed under the system were evaluated under the scanning electron microscope (SEM). Results. SEM micrographs demonstrated mushroom-shaped structures, corresponding to a mature E. faecalis biofilm. In the mature biofilm bacterial cells are totally encased in a polymeric extracellular matrix. Conclusions. The proposed in vitro system model provides an additional useful tool to study the biofilm concept in endodontic microbiology, allowing for a better understanding of persistent root canal infections. PMID:25371913

  19. GAL promoter-driven heterologous gene expression in Saccharomyces cerevisiae Δ strain at anaerobic alcoholic fermentation.

    PubMed

    Ahn, Jungoh; Park, Kyung-Min; Lee, Hongweon; Son, Yeo-Jin; Choi, Eui-Sung

    2013-02-01

    The removal of Gal80 protein by gene disruption turned into efficient GAL promoter-driven heterologous gene expression under anaerobic alcoholic fermentation of Saccharomyces cerevisiae. Using lipase B from Candida antarctica as a reporter, the relative strength of GAL10 promoter (P(GAL10) ) in Δgal80 mutant that does not require galactose as an inducer was compared to those of ADH1, PDC1, and PGK promoters, which have been known to work well anaerobically in actively fermenting yeast cells under high glucose concentration. P(GAL10) in the Δgal80 mutant showed 0.8-fold (ADH1), fourfold (PDC1), and 50-fold (PGK) in promoter strength.

  20. Anaerobic Antimicrobial Therapy After Necrotizing Enterocolitis in VLBW Infants

    PubMed Central

    Autmizguine, Julie; Hornik, Christoph P.; Benjamin, Daniel K.; Laughon, Matthew M.; Clark, Reese H.; Cotten, C. Michael; Cohen-Wolkowiez, Michael; Benjamin, Daniel K.

    2015-01-01

    OBJECTIVE: To evaluate the effect of anaerobic antimicrobial therapy for necrotizing enterocolitis (NEC) on clinical outcomes in very low birth weight (≤1500 g) infants. METHODS: We identified very low birth weight infants with NEC from 348 US NICUs from 1997 to 2012. Anaerobic antimicrobial therapy was defined by antibiotic exposure on the first day of NEC. We matched (1:1) infants exposed to anaerobic antimicrobial therapy with infants who were not exposed by using a propensity score stratified by NEC severity (medical and surgical). The primary composite outcome was in-hospital death or intestinal stricture. We assessed the relationship between anaerobic antimicrobial therapy and outcome by using a conditional logistic regression on the matched cohort. RESULTS: A total of 1390 infants exposed to anaerobic antimicrobial therapy were matched with 1390 infants not exposed. Mean gestational age and birth weight were 27 weeks and 946 g, respectively, and were similar in both groups. We found no significant difference in the combined outcome of death or strictures, but strictures as a single outcome were more common in the anaerobic antimicrobial therapy group (odds ratio 1.73; 95% confidence interval, 1.11–2.72). Among infants with surgical NEC, mortality was less common with anaerobic antimicrobial therapy (odds ratio 0.71; 95% confidence interval, 0.52–0.95). CONCLUSIONS: Anaerobic antimicrobial therapy was not associated with the composite outcome of death or strictures but was associated with an increase in intestinal strictures. This higher incidence of intestinal strictures may be explained by the fact that death is a competing outcome for intestinal strictures, and mortality was slightly lower in the anaerobic cohort. Infants with surgical NEC who received anaerobic antimicrobial therapy had lower mortality. PMID:25511117

  1. Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

    PubMed Central

    Müller, Miklós; Mentel, Marek; van Hellemond, Jaap J.; Henze, Katrin; Woehle, Christian; Gould, Sven B.; Yu, Re-Young; van der Giezen, Mark

    2012-01-01

    Summary: Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified. PMID:22688819

  2. Periplasmic Manganese in a Subsurface Bacterium During Anaerobic Growth on Birnessite

    NASA Astrophysics Data System (ADS)

    Langley, S.; Glasauer, S.; Beveridge, T.

    2002-12-01

    In subsurface environments, where oxygen is not metabolically available for energy production, bacteria use alternate terminal electron acceptors (TEAs) to respire and grow. Anaerobic TEAs include, but are not limited to, Fe3+ and Mn4+. These metals can be present as mineral phases (e.g., ferrihydrite and hematite in the case of iron; birnessite and pyrolusite in the case of manganese). Bacteria bind strongly to minerals and reduce the metal by a process called dissimilatory metal reduction (DMR). Shewanella putrefaciens strain CN32 is a Gram-negative bacterium capable of DMR. In previous reports, when this organism was grown on birnessite, we observed cytoplasmic granules of a Mn-rich mineral phase, and an unusual deposition of electron-dense material within the periplasm (that region of the cell located between the inner and outer membranes). In an attempt to characterize the periplasmic precipitates, CN32 was inoculated into an anaerobic defined medium (DM), supplemented with 20 mM Mn (birnessite) and incubated in an anaerobic chamber. Reduced and total Mn concentrations were monitored using atomic absorption spectrophotometry, and cell numbers determined by viable counts on trypticase soy agar. TEM, combined with energy dispersive X-ray spectroscopy (EDS), was used to localize and confirm the presence of any Mn-rich depositions. Soluble Mn concentration increased steadily after inoculation, indicating active metabolism and metal reduction by the cells. Viable counts indicated that the cells reached their maximum number on day 9. Stained thin sections from 4-day-old samples examined with TEM showed cells in close association with the mineral. Secondary mineral products derived from birnessite reduction were evident (e.g., manganese phosphate). TEM-EDS also revealed the presence of ~30 nm-thick deposits of electron-dense material in the periplasm of some cells. However, examination of similar sections which had not been previously stained with osmium tetroxide

  3. Pathogen Characterization of Fresh and Stored Mesophilic Anaerobically Digested Biosolids.

    PubMed

    A, Cecily

    2017-01-13

    Culturable bacterial pathogens (Campylobacter, Salmonella, Listeria, Yersinia) and indicators (E. coli, enterococci, Clostridium perfringens) were quantified at six wastewater treatment plants that land apply anaerobically digested biosolids in Ontario, Canada. Cryptosporidium parvum and Giardia lamblia were also quantified by PCR. Salmonella and Listeria were frequently detected in sludge and liquid biosolids (70-100% of samples) but less often in fresh dewatered cake biosolids (50-60%); with low levels in fresh cake (<100 cells/g dw). Yersinia were in 20-30% of samples, typically at very low levels (<10 cell/g dw). Giardia and Cryptosporidium were detected in 80% and 20% of cake biosolids at geometric means of 270 cysts/g dw and 70 oocysts/g dw, respectively. E. coli reduction was typically >2-log10 while pathogen reduction was variable. "Sudden increase" of pathogens was not observed, however, Salmonella and E. coli showed regrowth (at 1 to 3 orders of magnitude) after 2 to 3 day storage at 30°C.

  4. Complete Genome Sequence of Finegoldia magna, an Anaerobic Opportunistic Pathogen

    PubMed Central

    Goto, Takatsugu; Yamashita, Atsushi; Hirakawa, Hideki; Matsutani, Minenosuke; Todo, Kozo; Ohshima, Kenshiro; Toh, Hidehiro; Miyamoto, Kazuaki; Kuhara, Satoru; Hattori, Masahira; Shimizu, Tohru; Akimoto, Shigeru

    2008-01-01

    Finegoldia magna (formerly Peptostreptococcus magnus), a member of the Gram-positive anaerobic cocci (GPAC), is a commensal bacterium colonizing human skin and mucous membranes. Moreover, it is also recognized as an opportunistic pathogen responsible for various infectious diseases. Here, we report the complete genome sequence of F. magna ATCC 29328. The genome consists of a 1 797 577 bp circular chromosome and an 189 163 bp plasmid (pPEP1). The metabolic maps constructed based on the genome information confirmed that most F. magna strains cannot ferment most sugars, except fructose, and have various aminopeptidase activities. Three homologs of albumin-binding protein, a known virulence factor useful for antiphagocytosis, are encoded on the chromosome, and one albumin-binding protein homolog is encoded on the plasmid. A unique feature of the genome is that F. magna encodes many sortase genes, of which substrates may be involved in bacterial pathogenesis, such as antiphagocytosis and adherence to the host cell. The plasmid pPEP1 encodes seven sortase and seven substrate genes, whereas the chromosome encodes four sortase and 19 substrate genes. These plasmid-encoded sortases may play important roles in the pathogenesis of F. magna by enriching the variety of cell wall anchored surface proteins. PMID:18263572

  5. [Properties of anaerobic granules developed by bioflocculant].

    PubMed

    Wang, Jing-Song

    2009-11-01

    Three identical UASB reactors (labeled R1, R2, R3) were applied to treat synthetic wastewater of COD concentration 5 500-6 500 mg x L(-1). Under the same process conditions, R1 was operated with addition of 7.5 g CaCl2 and 400 mL bioflocculant MBF21 weekly, R2 was operated with addition of 140 mg cationic PAM weekly, R3 was operated without any addition of flocculants served as control. The objectives of this study were to investigate the effect of bioflocculant MBF21 on development of anaerobic granules and compare it to cationic PAM. The results showed that after 67 days of operation, anaerobic granules developed in these three UASB reactors. The average diameters of granules in R1, R2 and R3 were 1.18, 1.21 and 0.76 mm, respectively, the granulation rates in R1, R2, R3 were 15.37, 15.82 and 9.10 microm x d(-1), respectively, the values of SMA (COD-CH4/VSS x t) of granules were 0.740, 0.657 and 0.558 g x (g x d)(-1), respectively, the VSS/SS of granules were 0.667, 0.629 and 0.607, respectively, the SVI of granules were 14.7, 13.1 and 20.4 mL x g(-1), respectively, the densities of granules were 1.061, 1.064 and 1.054 g x cm(-3), respectively, the integrity coefficients of granules were 92.1, 93.5 and 84.7, respectively. From the photos of SEM, granules developed in R1 and R2 were tighter than those in R3. In the formation of mature granules, all the three reactors showed similar laws, i.e. filamentous microorganisms were predominant on the surface of the seed sludge while bacillus and cocci bacteria were predominant on the surface of the mature granules. This study demonstrated that in the development of anaerobic granules, the effect of bioflocculant MBF21 on enhancement the physical properties of granules was similar to cationic PAM, but the effect of bioflocculant MBF21 on improvement of biochemical and physiological properties of granules was better than cationic PAM.

  6. Anaerobic and sequential aerobic production of high-titer ethanol and single cell protein from NaOH-pretreated corn stover by a genome shuffling-modified Saccharomyces cerevisiae strain.

    PubMed

    Ren, Xueliang; Wang, Juncong; Yu, Hui; Peng, Chunlan; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Liang, Yunxiang; Peng, Nan

    2016-10-01

    In this study, a Saccharomyces cerevisiae recombinant strain 14 was constructed through genome shuffling method by transferring the whole genomic DNA of Candida intermedia strain 23 into a thermo-tolerant S. cerevisiae strain. The recombinant strain 14 combined the good natures of both parent strains that efficiently produced ethanol from glucose and single cell protein from xylose with 54.6% crude protein and all essential amino acids except cysteine at 35°C. Importantly, the recombinant strain 14 produced 64.07g/L ethanol from 25%(w/v) NaOH-pretreated and washed corn stover with the ethanol yield of 0.26g/g total stover by fed-batch simultaneous saccharification and fermentation and produced 66.50g/L dry cell mass subsequently from the residual hydrolysate and ethanol. Therefore, this study represents a feasible method to comprehensively utilize hexose and pentose in lignocellulosic materials.

  7. Estimation of Anaerobic Debromination Rate Constants of PBDE Pathways Using an Anaerobic Dehalogenation Model.

    PubMed

    Karakas, Filiz; Imamoglu, Ipek

    2017-04-01

    This study aims to estimate anaerobic debromination rate constants (km) of PBDE pathways using previously reported laboratory soil data. km values of pathways are estimated by modifying a previously developed model as Anaerobic Dehalogenation Model. Debromination activities published in the literature in terms of bromine substitutions as well as specific microorganisms and their combinations are used for identification of pathways. The range of estimated km values is between 0.0003 and 0.0241 d(-1). The median and maximum of km values are found to be comparable to the few available biologically confirmed rate constants published in the literature. The estimated km values can be used as input to numerical fate and transport models for a better and more detailed investigation of the fate of individual PBDEs in contaminated sediments. Various remediation scenarios such as monitored natural attenuation or bioremediation with bioaugmentation can be handled in a more quantitative manner with the help of km estimated in this study.

  8. Mineralization and kinetics of Reactive Brilliant Red X-3B by a combined anaerobic-aerobic bioprocess inoculated with the coculture of fungus and bacterium.

    PubMed

    Shi, Shengnan; Ma, Fang; Sun, Tieheng; Li, Ang; Zhou, Jiti; Qu, Yuanyuan

    2014-01-01

    Mineralization of Reactive Brilliant Red X-3B by a combined anaerobic-aerobic process which was inoculated with the co-culture of Penicillium sp. QQ and Exiguobacterium sp. TL was studied. The optimal conditions of decolorization were investigated by response surface methodology as follows: 132.67 g/L of strain QQ wet spores, 1.09 g/L of strain TL wet cells, 2.25 g/L of glucose, 2.10 g/L of yeast extract, the initial dye concentration of 235.14 mg/L, pH 6.5, and 33 °C. The maximal decolorization rate was about 96 % within 12 h under the above conditions. According to the Haldane kinetic equation, the maximal specific decolorization rate was 89.629 mg/g˙h. It was suggested that in the anaerobic-aerobic combined process, decolorization occurred in the anaerobic unit and chemical oxygen demand (COD) was mainly removed in the aerobic one. Inoculation of fungus QQ in the anaerobic unit was important for mineralization of X-3B. Besides, the divided anaerobic-aerobic process showed better performance of COD removal than the integrated one. It was suggested that the combined anaerobic-aerobic process which was inoculated with co-culture was potentially useful for the field application.

  9. In silico design of anaerobic growth-coupled product formation in Escherichia coli: experimental validation using a simple polyol, glycerol.

    PubMed

    Balagurunathan, Balaji; Jain, Vishist Kumar; Tear, Crystal Jing Ying; Lim, Chan Yuen; Zhao, Hua

    2017-03-01

    Integrated approaches using in silico model-based design and advanced genetic tools have enabled efficient production of fuels, chemicals and functional ingredients using microbial cell factories. In this study, using a recently developed genome-scale metabolic model for Escherichia coli iJO1366, a mutant strain has been designed in silico for the anaerobic growth-coupled production of a simple polyol, glycerol. Computational complexity was significantly reduced by systematically reducing the target reactions used for knockout simulations. One promising penta knockout E. coli mutant (E. coli ΔadhE ΔldhA ΔfrdC ΔtpiA ΔmgsA) was selected from simulation study and was constructed experimentally by sequentially deleting five genes. The penta mutant E. coli bearing the Saccharomyces cerevisiae glycerol production pathway was able to grow anaerobically and produce glycerol as the major metabolite with up to 90% of theoretical yield along with stoichiometric quantities of acetate and formate. Using the penta mutant E. coli strain we have demonstrated that the ATP formation from the acetate pathway was essential for growth under anaerobic conditions. The general workflow developed can be easily applied to anaerobic production of other platform chemicals using E. coli as the cell factory.

  10. Degradation of natural and synthetic polyesters under anaerobic conditions.

    PubMed

    Abou-Zeid, D M; Müller, R J; Deckwer, W D

    2001-03-30

    Often, degradability under anaerobic conditions is desirable for plastics claimed to be biodegradable, e.g. in anaerobic biowaste treatment plants, landfills and in natural anaerobic sediments. The biodegradation of the natural polyesters poly(beta-hydroxybutyrate) (PHB), poly(beta-hydroxybutyrate-co-11.6%-beta-hydroxyvalerate) (PHBV) and the synthetic polyester poly(epsilon-caprolactone) (PCL) was studied in two anaerobic sludges and individual polyester degrading anaerobic strains were isolated, characterized and used for degradation experiments under controlled laboratory conditions. Incubation of PHB and PHBV films in two anaerobic sludges exhibited significant degradation in a time scale of 6-10 weeks monitored by weight loss and biogas formation. In contrast to aerobic conditions, PHB was degraded anaerobically more rapidly than the copolyester PHBV, when tested with either mixed cultures or a single strained isolate. PCL tends to degrade slower than the natural polyesters PHB and PHBV. Four PHB and PCL degrading isolates were taxonomically identified and are obviously new species belonging to the genus Clostridium group I. The depolymerizing enzyme systems of PHB and PCL degrading isolates are supposed to be different. Using one isolated strain in an optimized laboratory degradation test with PHB powder, the degradation time was drastically reduced compared to the degradation in sludges (2 days vs. 6-10 weeks).

  11. Trace metal speciation and bioavailability in anaerobic digestion: A review.

    PubMed

    Thanh, Pham Minh; Ketheesan, Balachandran; Yan, Zhou; Stuckey, David

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR).

  12. Effect of nitrate on anaerobic azo dye reduction.

    PubMed

    Cirik, Kevser; Kitiş, Mehmet; Çinar, Özer

    2013-01-01

    The aim of the study was to investigate the effect of nitrate on anaerobic color removal efficiencies. For this aim, anaerobic-aerobic sequencing batch reactor (SBR) fed with a simulated textile effluent including Remazol Brilliant Violet 5R azo dye was operated with a total cycle time of 12 h, including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (nitrate) and performance of the system was determined by monitoring color removal efficiency, nitrate removal, nitrite formation and removal, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2 dioxygenase), and formation and removal of aromatic amines. Variations of population dynamics of microorganisms exposed to various amount of nitrate were identified by denaturing gradient gel electrophoresis (DGGE). It was found that nitrate has adverse effect on anaerobic color removal efficiency and color removal was achieved after denitrification process was completed. It was found that nitrate stimulates the COD removal efficiency and accelerates the COD removal in the first hour of anaerobic phase. About 90 % total COD removal efficiencies were achieved in which microorganism exposed to increasing amount of nitrate. Population dynamics of microorganisms exposed to various amount of nitrate were changed and diversity was increased.

  13. Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor

    PubMed Central

    Wang, Jin; Mahmood, Qaisar; Qiu, Jiang-Ping; Li, Yin-Sheng; Chang, Yoon-Seong; Li, Xu-Dong

    2015-01-01

    Large volumes of untreated palm oil mill effluent (POME) pose threat to aquatic environment due to the presence of very high organic content. The present investigation involved two pilot-scale anaerobic expanded granular sludge bed (EGSB) reactors, continuously operated for 1 year to treat POME. Setting HRT at 9.8 d, the anaerobic EGSB reactors reduced COD from 71179 mg/L to 12341 mg/L and recycled half of sludge by a dissolved air flotation (DAF). The average effluent COD was 3587 mg/L with the consistent COD removal efficiency of 94.89%. Adding cationic polymer (PAM) dose of 30 mg/L to DAF unit and recycling its half of sludge caused granulation of anaerobic sludge. Bacilli and small coccid bacteria were the dominant microbial species of the reactor. The reactor produced 27.65 m3 of biogas per m3 of POME which was utilized for electricity generation. PMID:26167485

  14. Kinetics of biogas production in Anaerobic Filters.

    PubMed

    Krümpel, Johannes; Schäufele, Friedrich; Schneider, Johannes; Jungbluth, Thomas; Zielonka, Simon; Lemmer, Andreas

    2016-01-01

    This study investigates methane production kinetics from individual volatile fatty acids (VFA) in an Upflow Anaerobic Filter (AF). 1gCOD in the form of acetic (HAc), propionic (HPr) or butyric acid (HBu) was injected into the AF while operating at an organic loading rate (OLRCOD) of 3.5gL(-1)d(-1). A new method is introduced to separate gas production of the baseload from the product formation of VFA degradation after the injection. The lag phase, fractional rate of gas production and half-life has been determined for the methane production of the three VFAs. The half-lives were in the order HAc

  15. [Antimicrobial susceptibility testing of anaerobic bacteria].

    PubMed

    García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada

    2014-02-01

    The anaerobic bacteria resistance to antibiotics is increasing, and even has appeared against the most active of those, like metronidazol and carbapenems. This fact forces to make and periodical sensibility tests -at least in the most aggressive and virulent species, in cases that they are isolated from life locations and in the absence of therapeutic response- to check the local sensibility and to establish suitable empiric therapies, all based on multicentric studies carried out in order to this or well to check the activity of new antibiotics. For the laboratory routine, the easiest sensibility method is the E-test/MIC evaluator. Another alternative is microdilution, that's only normalized for Bacteroides. There are preliminary facts that allow the use of disc diffusion method in some species of Bacteroides and Clostridium. For the temporal and multicentric studies, the procedure is dilution in agar plate, the reference method.

  16. Photoenhanced anaerobic digestion of organic acids

    DOEpatents

    Weaver, Paul F.

    1990-01-01

    A process is described for rapid conversion of organic acids and alcohols anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (e.g., solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion or organic acids and alcohols into methane with low levels of light energy input.

  17. Degradation of methyl bromide in anaerobic sediments

    USGS Publications Warehouse

    Oremland, R.S.; Miller, L.G.; Strohmaler, F.E.

    1994-01-01

    Methyl bromide (MeBr) was anaerobically degraded in saltmarsh sediments after reaction with sulfide. The product of this nucleophilic substitution reaction was methanethiol, which underwent further chemical and bacterial reactions to form dimethyl sulfide. These two gases appeared transiently during sediment incubations because they were metabolized by methanogenic and sulfate-reducing bacteria. A second, less significant reaction of MeBr was the exchange with chloride, forming methyl chloride, which was also susceptible to attack by sulfide. Incubation of 14C-labeled methyl iodide as an analogue of MeBr resulted in the formation of 14CH4 and 14CO2 and also indicated that sulfate-reducing bacteria as well as methanogens metabolized the methylated sulfur intermediates. These results suggest that exposed sediments with abundant free sulfide, such as coastal salt-marshes, may constitute a sink for atmospheric MeBr.

  18. PCB dechlorination in anaerobic soil slurry reactors

    SciTech Connect

    Klasson, K.T.; Evans, B.S.

    1993-11-29

    Many industrial locations, including the US Department of Energy`s, have identified needs for treatment of polychlorinated biphenyl (PCB) wastes and remediation of PCB-contaminated sites. Biodegradation of PCBs is a potentially effective technology for the treatment of PCB-contaminated soils and sludges, including mixed wastes; however, a practical remediation technology has not yet been demonstrated. In laboratory experiments, soil slurry bioreactors inoculated with microorganisms extracted from PCB-contaminated sediments from the Hudson River have been used to obtain anaerobic dechlorination of PCBS. The onset of dechlorination activity can be accelerated by addition of nutritional amendments and inducers. After 15 weeks of incubation with PCB-contaminated soil and nutrient solution, dechlorination has been observed under several working conditions. The best results show that the average chlorine content steadily dropped from 4.3 to 3.5 chlorines per biphenyl over a 15-week period.

  19. Determining anaerobic degradation kinetics from batch tests.

    PubMed

    Moreda, Iván López

    2016-01-01

    Data obtained from a biomethane potential (BMP) test were used in order to obtain the parameters of a kinetic model of solid wastes anaerobic degradation. The proposed model considers a hydrolysis step with a first order kinetic, a Monod kinetic for the soluble organic substrate degradation and a first order decay of microorganisms. The instantaneous release of methane was assumed. The parameters of the model are determined following a direct search optimization procedure. A 'multiple-shooting' technique was used as a first step of the optimization process. The confidence interval of the parameters was determined by using Monte Carlo simulations. Also, the distribution functions of the parameters were determined. Only the hydrolysis first order constant shows a normal distribution.

  20. Invited review: anaerobic fermentation of dairy food wastewater.

    PubMed

    Hassan, A N; Nelson, B K

    2012-11-01

    Dairy food wastewater disposal represents a major environmental problem. This review discusses microorganisms associated with anaerobic digestion of dairy food wastewater, biochemistry of the process, factors affecting anaerobic digestion, and efforts to develop defined cultures. Anaerobic digestion of dairy food wastewater offers many advantages over other treatments in that a high level of waste stabilization is achieved with much lower levels of sludge. In addition, the process produces readily usable methane with low nutrient requirements and no oxygen. Anaerobic digestion is a series of complex reactions that broadly involve 2 groups of anaerobic or facultative anaerobic microorganisms: acidogens and methanogens. The first group of microorganisms breaks down organic compounds into CO(2) and volatile fatty acids. Some of these organisms are acetogenic, which convert long-chain fatty acids to acetate, CO(2), and hydrogen. Methanogens convert the acidogens' products to methane. The imbalance among the different microbial groups can lead not only to less methane production, but also to process failure. This is due to accumulation of intermediate compounds, such as volatile fatty acids, that inhibit methanogens. The criteria used for evaluation of the anaerobic digestion include levels of hydrogen and volatile fatty acids, methane:carbon ratio, and the gas production rate. A steady state is achieved in an anaerobic digester when the pH, chemical oxygen demand of the effluent, the suspended solids of the effluent, and the daily gas production remain constant. Factors affecting efficiency and stability of the process are types of microorganisms, feed C:N ratio, hydraulic retention time, reactor design, temperature, pH control, hydrogen pressure, and additives such as manure and surfactants. As anaerobic digesters become increasingly used in dairy plants, more research should be directed toward selecting the best cultures that maximize methane production from dairy

  1. Anionic metabolite biosynthesis enhanced by potassium under dark, anaerobic conditions in cyanobacteria

    PubMed Central

    Ueda, Sakiko; Kawamura, Yuhki; Iijima, Hiroko; Nakajima, Mitsuharu; Shirai, Tomokazu; Okamoto, Mami; Kondo, Akihiko; Hirai, Masami Yokota; Osanai, Takashi

    2016-01-01

    Potassium (K+) is an essential macronutrient for all living organisms including cyanobacteria. Cyanobacteria are a group of bacteria performing oxygenic photosynthesis, widely studied in basic and applied sciences. The primary metabolism of the unicellular cyanobacterium Synechocystis sp. PCC 6803 is altered by environmental conditions, and it excretes organic acids and hydrogen under dark, anaerobic conditions. Here we demonstrated that K+ widely changes the primary carbon metabolism of this cyanobacterium. Succinate and lactate excretion from the cells incubated under dark, anaerobic conditions was enhanced in the presence of K+, while hydrogen production was repressed. The addition of K+ and the genetic manipulation of acetate kinase AckA and an RNA polymerase sigma factor SigE additively increased succinate and lactate production to 141.0 and 217.6 mg/L, which are 11 and 46 times, compared to the wild-type strain without K+, respectively. Intracellular levels of 2-oxoglutarate, succinate, fumarate, and malate increased by K+ under dark, anaerobic conditions. This study provides the evidence of the considerable effect of K+ on the biosynthesis of anionic metabolites in a unicellular cyanobacterium. PMID:27576448

  2. Anaerobic conversion of microalgal biomass to sustainable energy carriers--a review.

    PubMed

    Lakaniemi, Aino-Maija; Tuovinen, Olli H; Puhakka, Jaakko A

    2013-05-01

    This review discusses anaerobic production of methane, hydrogen, ethanol, butanol and electricity from microalgal biomass. The amenability of microalgal biomass to these bioenergy conversion processes is compared with other aquatic and terrestrial biomass sources. The highest energy yields (kJ g(-1) dry wt. microalgal biomass) reported in the literature have been 14.8 as ethanol, 14.4 as methane, 6.6 as butanol and 1.2 as hydrogen. The highest power density reported from microalgal biomass in microbial fuel cells has been 980 mW m(-2). Sequential production of different energy carriers increases attainable energy yields, but also increases investment and maintenance costs. Microalgal biomass is a promising feedstock for anaerobic energy conversion processes, especially for methanogenic digestion and ethanol fermentation. The reviewed studies have mainly been based on laboratory scale experiments and thus scale-up of anaerobic utilization of microalgal biomass for production of energy carriers is now timely and required for cost-effectiveness comparisons.

  3. Pyrosequencing reveals microbial community profile in anaerobic bio-entrapped membrane reactor for pharmaceutical wastewater treatment.

    PubMed

    Ng, Kok Kwang; Shi, Xueqing; Ong, Say Leong; Ng, How Yong

    2016-01-01

    In this study, pharmaceutical wastewater with high salinity and total chemical oxygen demand (TCOD) was treated by an anaerobic membrane bioreactor (AnMBR) and an anaerobic bio-entrapped membrane reactor (AnBEMR). The microbial populations and communities were analyzed using the 454 pyrosequencing method. The hydraulic retention time (HRT), membrane flux and mean cell residence time (MCRT) were controlled at 30.6h, 6L/m(2)h and 100d, respectively. The results showed that the AnBEMR achieved higher TCOD removal efficiency and greater biogas production compared to the AnMBR. Through DNA pyrosequencing analysis, both the anaerobic MBRs showed similar dominant groups of bacteria and archaea. However, phylum Elusimicrobia of bacteria was only detected in the AnBEMR; the higher abundance of dominant archaeal genus Methanimicrococcus found in the AnBEMR could play an important role in degradation of the major organic pollutant (i.e., trimethylamine) present in the pharmaceutical wastewater.

  4. Enhanced methane production from microalgal biomass by anaerobic bio-pretreatment.

    PubMed

    He, Shuai; Fan, Xiaolei; Katukuri, Naveen Reddy; Yuan, Xianzheng; Wang, Fei; Guo, Rong-Bo

    2016-03-01

    Anaerobic digestion (AD) of microalgal biomass is one of the most energy efficient technologies to convert microalgae to biofuels. In order to improve the biogas productivity, breaking up the tough and rigid cell wall of microalgae by pretreatment is necessary. In this work, Bacillus licheniformis, a facultative anaerobic bacterial with hydrolytic and acidogenic activities, was adopted to pretreat Chlorella sp. In the established pretreatment process, pure bacterial culture (0%, 1%, 2%, 4%, 8%, v/v) were used to pretreat Chlorella sp. under anaerobic condition at 37°C for 60 h. The soluble chemical oxygen demands (SCOD) content was increased by 16.4-43.4%, while volatile fatty acids (VFAs) were improved by 17.3-44.2%. Furthermore, enhancement of methane production (9.2-22.7%) was also observed in subsequent AD. The results indicated that the more dosages of bacteria were used to pretreat the microalgal biomass in the range of 1-8%, the more methane was produced.

  5. Anaerobic High-Throughput Cultivation Method for Isolation of Thermophiles Using Biomass-Derived Substrates

    SciTech Connect

    Hamilton-Brehm, Scott; Vishnivetskaya, Tatiana A; Allman, Steve L; Mielenz, Jonathan R; Elkins, James G

    2012-01-01

    Flow cytometry (FCM) techniques have been developed for sorting mesophilic organisms, but the difficulty increases if the target microbes are thermophilic anaerobes. We demonstrate a reliable, high-throughput method of screening thermophilic anaerobic organisms using FCM and 96-well plates for growth on biomass-relevant substrates. The method was tested using the cellulolytic thermophiles Clostridium ther- mocellum (Topt = 55 C), Caldicellulosiruptor obsidiansis (Topt = 78 C) and the fermentative hyperthermo- philes, Pyrococcus furiosus (Topt = 100 C) and Thermotoga maritima (Topt = 80 C). Multi-well plates were incubated at various temperatures for approximately 72 120 h and then tested for growth. Positive growth resulting from single cells sorted into individual wells containing an anaerobic medium was verified by OD600. Depending on the growth substrate, up to 80 % of the wells contained viable cultures, which could be transferred to fresh media. This method was used to isolate thermophilic microbes from Rabbit Creek, Yellowstone National Park (YNP), Wyoming. Substrates for enrichment cultures including crystalline cellulose (Avicel), xylan (from Birchwood), pretreated switchgrass and Populus were used to cultivate organisms that may be of interest to lignocellulosic biofuel production.

  6. Toxicity and biodegradability of selected N-substituted phenols under anaerobic conditions

    SciTech Connect

    Donlon, B.; Razo-Flores, E.; Hwu, C.S.; Field, J.; Lettinga, G.

    1995-12-31

    The anaerobic toxicity and biodegradability of N-substituted aromatics were evaluated in order to obtain information on their ultimate biotreatment. The toxicity of selected N-substituted aromatic compounds toward acetoclastic methanogens in granular sludge was measured in batch assays. This toxicity was highly correlated with compound hydrophobicity, indicating that partitioning into the bacterial membranes was an important factor in the toxicity. However, other factors, such as chemical interactions with key cell components, were suggested to be playing an important role. Nitroaromatic compounds were, on the average, over 300-fold more toxic than their amino-substituted counterparts. This finding suggests that the facile reduction of nitro-groups known to occur in anaerobic environments would result in a high level of detoxification. To test this hypothesis, continuous lab-scale upward-flow anaerobic sludge bed reactors treating 2-nitrophenol and 4-nitrophenol were established. The 4-nitrophenol was readily converted to the corresponding 4-aminophenol, whereas complete mineralization of 2-nitrophenol via intermediate formation of 2-aminophenol was obtained. These conversions led to a dramatic detoxification of the nitrophenols, because it was feasible to treat the highly toxic nitrophenolics at high organic loading rates.

  7. Continuous determination of volatile products in anaerobic fermenters by on-line capillary gas chromatography.

    PubMed

    Diamantis, V; Melidis, P; Aivasidis, A

    2006-07-28

    Bio-ethanol and biogas produced during the anaerobic conversion of organic compounds has been a subject of great interest since the oil crisis of the 1970s. In ethanol fermentation and anaerobic treatment of wastewaters, end-product (ethanol) and intermediate-products (short-chain fatty acids, SCFA) cause inhibition that results in reduced process efficiency. Control of these constituents is of utmost importance for bioreactor optimization and process stability. Ethanol and SCFA can be detected with precision by capillary gas chromatography usually conducted in off-line measurements. In this work, an on-line monitoring and controlling system was developed and connected to the fermenter via an auto-sampling equipment, which could perform the feeding, filtration and dilution of the sample and final injection into the gas chromatograph through an automation-based programmed procedure. The sample was continuously pumped from the recycle stream of the bioreactor and treated using a microfiltration unit. The concentrate was returned to the reactor while the permeate was quantitatively mixed with an internal standard solution. The system comprised of a gas chromatograph with the flow cell and one-shot sampler and a PC with the appropriate software. The on-line measurement of ethanol and SCFA, directly from the liquid phase of an ethanol fermenter and a high-rate continuous mode anaerobic digester, was accomplished by gas chromatography. Also, this monitoring and controlling system was proved to be effective in the continuous fermentation of alcohol-free beer.

  8. Decolorization of azo dyes under batch anaerobic and sequential anaerobic/aerobic conditions.

    PubMed

    Işik, Mustafa; Sponza, Delia Teresa

    2004-01-01

    Batch anaerobic and sequential anaerobic upflow anaerobic sludge blanket (UASB)/aerobic continuous stirred tank reactor (CSTR) were used to determine the color and COD removals under anaerobic/aerobic conditions. Two azo dyes namely "Reactive Black 5 (RB 5)," "Congo Red (CR)," and glucose as a carbon source were used for synthetic wastewater. The course of the decolorization process approximates to first order and zero order kinetics with respect to dye concentration for RB 5 and Congo Red azo dyes, respectively, in batch conditions. The decolorization kinetic constant (K0) values increased from 3.6 to 11.8 mg(L h)(-1) as increases in dye concentrations from 200 to 3200 mg L(-1) for CR. Increases in dye concentrations from 0 to 3200 mg L(-1) reduce the decolorization rate constant (k1) values from 0.0141 to 0.0019 h(-1) in batch studies performed with RB 5. Decolorization was achieved effectively under test conditions but ultimate decolorization of azo dyes was not observed at all dye concentrations in batch assay conditions. Dye concentrations of 100 mg L(-1) and 3000 mg L(-1) of glucose-COD containing basal medium were used for continuous studies. The effect of organic loadings and HRT, on the color removal efficiencies and methane gas productions were monitored. 94.1-45.4% COD and 79-73% color removal efficiencies were obtained at an organic system during decolorization of Reactive Black 5. 92.3-77.0% COD and 95.3-92.2% decolorization efficiencies were achieved at a organic loading rate of 1.03-6.65 kg (m3 day)(-1) and a HRT of 3.54-0.49 for Congo Red treatment. The results of this study showed that, although decolorization continued, COD removal efficiencies and methane gas production were depressed at high organic loadings under anaerobic conditions. Furthermore, VFA accumulation, alkalinity consumption, and methane gas percentage were monitored at organic loading as high as 2.49-4.74 kg (m3 day)(-1) and 24.60-30.62 kg (m3 day)(-1), respectively, through the

  9. A genomic island of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough promotes survival under stress conditions while decreasing the efficiency of anaerobic growth.

    PubMed

    Johnston, Shawna; Lin, Shiping; Lee, Phoebe; Caffrey, Sean M; Wildschut, Janine; Voordouw, Johanna K; da Silva, Sofia M; Pereira, Ines A C; Voordouw, Gerrit

    2009-04-01

    A 47 kb genomic island (GEI) bracketed by 50 bp direct repeats, containing 52 annotated genes, was found to delete spontaneously from the genome of Desulfovibrio vulgaris Hildenborough. The island contains genes for site-specific recombinases and transposases, rubredoxin:oxygen oxidoreductase-1 (Roo1) and hybrid cluster protein-1 (Hcp1), which promote survival in air and nitrite stress. The numbering distinguishes these from the Roo2 and Hcp2 homologues for which the genes are located elsewhere in the genome. Cells with and without the island (GEI(+) and GEI(-) cells respectively) were obtained by colony purification. GEI(-) cells arise in anaerobic cultures of colony-purified GEI(+) cells, indicating that the site-specific recombinases encoded by the island actively delete this region. GEI(+) cells survive better in microaerophilic conditions due to the presence of Roo1, whereas the Hcps appear to prevent inhibition by sulfur and polysulfide, which are formed by chemical reaction of sulfide and nitrite. Hence, the island confers resistance to oxygen and nitrite stress. However, GEI(-) cells have a higher growth rate in anaerobic media. Microarrays and enzyme activity stains indicated that the GEI(-) cells have increased expression of genes, which promote anaerobic energy conservation, explaining the higher growth rate. Hence, while lowering the efficiency of anaerobic metabolism, the GEI increases the fitness of D. vulgaris under stress conditions, a feature reminiscent of pathogenicity islands which allow more effective colonization of environments provided by the targeted hosts.

  10. Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage

    PubMed Central

    Aida, Azrina A.; Kuroda, Kyohei; Yamamoto, Masamitsu; Nakamura, Akinobu; Hatamoto, Masashi; Yamaguchi, Takashi

    2015-01-01

    We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors. PMID:25817585

  11. The metagenome of an anaerobic microbial community decomposing poplar wood chips

    SciTech Connect

    van der Lelie D.; Taghavi, S.; McCorkle, S. M.; Li, L.-L.; Malfatti, S. A.; Monteleone, D.; Donohoe, B. S.; Ding, S.-Y.; Adney, W. S.; Himmel, M. E.; Tringe, S. G.

    2012-05-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic 'secretomes' that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to

  12. Gene and protein expression profiles of Shewanella oneidensis during anaerobic growth with different electron acceptors.

    SciTech Connect

    Beliaev, A. S.; Thompson, D. K.; Khare, T.; Lim, H.; Brandt, C. C.; Li, G.; Murray, A. E.; Heidelberg, J. F.; Giometti, C. S.; Yates, J., III; Nealson, K. H.; Tiedje, J. M.; Zhou, J.; Biosciences Division; ORNL; Scripps Research Inst.; Michigan State Univ.; The Inst. for Genomic Research; Jet Propulsion Laboratory; California Inst. of Tech.

    2002-01-01

    Changes in mRNA and protein expression profiles of Shewanella oneidenesis MR-1 during switch from aerobic to fumarate-, Fe(III)-, or nitrate-reducing conditions were examined using DNA microarrays and two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). In response to changes in growth conditions, 121 of the 691 arrayed genes displayed at least a two-fold difference in transcript abundance as determined by microarray analysis. Genes involved in aerobic respiration encoding cytochrome c and d oxidases and TCA cycle enzymes were repressed under anaerobic conditions. Genes induced during anaerobic respiration included those involved in cofactor biosynthesis and assembly (moaACE, ccmHF, nosD, cysG), substrate transport (cysUP, cysTWA, dcuB), and anaerobic energy metabolism (dmsAB, psrC, pshA, hyaABC, hydA). Transcription of genes encoding a periplasmic nitrate reductase (napBHGA), cytochrome c{sub 552}, and prismane was elevated 8- to 56-fold in response to the presence of nitrate, while cymA, ifcA, and frdA were specifically induced three- to eightfold under fumarate-reducing conditions. The mRNA levels for two oxidoreductase-like genes of unknown function and several cell envelope genes involved in multidrug resistance increased two- to fivefold specifically under Fe(III)-reducing conditions. Analysis of protein expression profiles under aerobic and anaerobic conditions revealed 14 protein spots that showed significant differences in abundance on 2-D gels. Protein identification by mass spectrometry indicated that the expression of prismane, dihydrolipoamide succinyltransferase, and alcaligin siderophore biosynthesis protein correlated with the microarray data.

  13. The Metagenome of an Anaerobic Microbial Community Decomposing Poplar Wood Chips

    PubMed Central

    van der Lelie, Daniel; Taghavi, Safiyh; McCorkle, Sean M.; Li, Luen-Luen; Malfatti, Stephanie A.; Monteleone, Denise; Donohoe, Bryon S.; Ding, Shi-You; Adney, William S.; Himmel, Michael E.; Tringe, Susannah G.

    2012-01-01

    This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic ‘secretomes’ that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point

  14. Anaerobic codigestion of dairy manure and food manufacturing waste for renewable energy generation in New York State

    NASA Astrophysics Data System (ADS)

    Rankin, Matthew J.

    Anaerobic digestion is a microbiological process that converts biodegradable organic material into biogas, consisting primarily of methane and carbon dioxide. Anaerobic digestion technologies have been integrated into wastewater treatment facilities nationwide for many decades to increase the economic viability of the treatment process by converting a waste stream into two valuable products: biogas and fertilizer. Thus, anaerobic digestion offers potential economic and environmental benefits of organic waste diversion and renewable energy generation. The use of biogas has many applications, including cogeneration, direct combustion, upgrading for conversion to feed a fuel cell, and compression for injection into the natural gas grid or for vehicular use. The potential benefits of waste diversion and renewable energy generation are now being realized by major organic waste generators in New York State, in particular the food manufacturing and dairy industries, thus warranting an analysis of the energy generation potential for these waste products. Anaerobic codigestion of dairy manure and food-based feedstocks reflects a cradle-to- cradle approach to organic waste management. Given both of their abundance throughout New York State, waste-to-energy processes represent promising waste management strategies. The objective of this thesis was to evaluate the current technical and economic feasibility of anaerobically codigesting existing dairy manure and food manufacturing waste feedstocks in New York State to produce high quality biogas for renewable energy generation. The first element to determining the technical feasibility of anaerobic codigestion potential in New York State was to first understand the feedstock availability. A comprehensive survey of existing organic waste streams was conducted. The key objective was to identify the volume and composition of dairy manure and liquid-phase food manufacturing waste streams available in New York State to make

  15. Bacterioferritin protects the anaerobe Desulfovibrio vulgaris Hildenborough against oxygen.

    PubMed

    Figueiredo, Mafalda C O; Lobo, Susana A L; Carita, João N; Nobre, Lígia S; Saraiva, Lígia M

    2012-08-01

    Intracellular free iron, is under aerobic conditions and via the Fenton reaction a catalyst for the formation of harmful reactive oxygen species. In this article, we analyzed the relation between intracellular iron storage and oxidative stress response in the sulfate reducing bacterium Desulfovibrio vulgaris Hildenborough, an anaerobe that is often found in oxygenated niches. To this end, we investigated the role of the iron storage protein bacterioferritin using transcriptomic and physiological approaches. We observed that transcription of bacterioferritin is strongly induced upon exposure of cells to an oxygenated atmosphere. When grown in the presence of high concentrations of oxygen the D. vulgaris bacterioferritin mutant exhibited, in comparison with the wild type strain, lower viability and a higher content of intracellular reactive oxygen species. Furthermore, the bacterioferritin gene is under the control of the oxidative stress response regulator D. vulgaris PerR. Altogether the data revealed a previously unrecognized ability for the iron storage bacterioferritin to contribute to the oxygen tolerance exhibited by D. vulgaris.

  16. Thioredoxin system of the phototsynthetic anaerobe Chromatium vinosum

    SciTech Connect

    Johnson, T.C.; Crawford, N.A.; Buchanan, B.B.

    1984-06-01

    Chromatium vinosum, an anaerobic photosynthetic purple sulfur bacterium, resembles aerobic bacterial cells in that it has an NADP-thioredoxin system composed of a single thioredoxin which is reduced by NADPH via NADP-thioredoxin reductase. Both protein components were purified to homogeneity, and some of their properties were determined. Chromatium vinosum thioredoxin was slightly larger than other bacterial thioredoxins (13 versus 12 kilodaltons) but was similar in its specificity (ability to activate chloroplasts NADP-malate dehydrogenase more effectively than chloroplast fructose-1,6-bisphosphatase) and immunological properties. As in other bacteria, Chromatium vinosum NADP-thioredoxin reductase was an arsenite-sensitive flavoprotein composed of two 33.5-kilodalton subunits, that required thioredoxin for the NADPH-linked reduction of 5,5'-dithiobis(2-nitrobenzoic acid). Chromatium vinosum NADP-thioredoxin reductase very effectively reduced several different bacterial-type thioredoxins (Escherichia coli, Chlorobium thiosulfatophilum (this name has not been approved by the International Committee of Systematic Bacteriolgy), Rhizobium meliloti) but not others (Clostridium pasteurianum, spinach chloroplast thioredoxin m). The results show that Chromatium vinosum contains an NADP-thioredoxin system typical of evolutionary more advanced microorganisms.

  17. Anaerobic CO2 fixation by the acetogenic bacterium Moorella thermoacetica

    SciTech Connect

    Hu, P; Rismani-Yazdi, H; Stephanopoulos, G

    2013-05-16

    Anaerobic bacteria such as Moorella thermoacetica have the capacity of fixing carbon dioxide with carbon monoxide and hydrogen for the production of ethanol, acetic acid, and other useful chemicals. In this study, we evaluated the fixation of CO2 for the production of acetic acid, as a product in its own right but also as precursor for lipid synthesis by oleaginous organisms. We achieved maximum cell optical density of 11.3, acetic acid titer of 31 g/L, and productivity of 0.55 g/L-h at CO mass-transfer rate of 83 mM/h. We also showed electron availability by CO mass transfer limited the process at CO mass transfer rates lower than 30 mM/h. Further enhancement of mass-transfer rate removed such limitations in favor of biological kinetics as main limitation. This work underlines the potential of microbial processes for converting syngas to fuel and chemical products in processes suitable for distributed feedstock utilization. (c) 2013 American Institute of Chemical Engineers AIChE J, 59: 3176-3183, 2013

  18. Glycerol production by anaerobic fermentation of molasses on pilot scale

    SciTech Connect

    Virkar, P.D.; Panesar, M.S.

    1987-04-20

    The use of sodium sulphite as a steering agent for enhancing the yield of glycerol during anaerobic ethanol fermentation is well established. Several studies have been reported in the literature using free as well as immobilized cells of Saccharomyces cerevisiae. In these studies it was observed that a relatively high concentration of sulphite in the fermentation broth, typically 40-100 g/l, was required to obtain a commercially significant yield of glycerol on sugar fermented. However, the dosing of large quantities of sulphite generally resulted in reduced viability of the microorganisms and slow fermentations. The glycerol concentration in the fermented broth was generally observed to be in the range 20-40 g/l. The low productivity coupled with the high cost of sulfite rendered the process commercially unattractive. In order to reduce the sulphite requirement, whilst at the same time increasing the productivity, a modified vacuum fermentation was developed in the laboratories. The process was successfully estabilished on a pilot scale and typical data obtained on scaleup are reported below. 8 references.

  19. Anaerobic and aerobic treatment of chlorinated, aliphatic compounds

    SciTech Connect

    Long, J.L.; Stensel, H.D.; Ferguson, J.F.; Strand, S.E.; Ongerth, J.E.

    1993-01-01

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). The anaerobic culture degraded seven of the feed CACs. The specialized aerobic cultures degraded all but three of the highly chlorinated CACs. The sequential system outperformed either of the other systems alone by degrading 10 of the feed CACs: chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,1,1-trichloroethane, hexachloroethane, 1,1-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, perchloroethylene, and 1,2,3-trichloropropane, plus the anaerobic metabolites: dichloromethane and cis-1,2-dichloroethylene.

  20. Sequential anaerobic-adsorption treatment of chemical industry wastewater.

    PubMed

    Daga, Kailash; Pallavi, V; Patel, Dharmendra

    2011-10-01

    Treatment technologies needed to reduce the pollutant load of chemical industry effluent have been found to involve exorbitantly high costs. The present investigation aimed to treat the wastewater from chemical industry by cost effective sequential anaerobic-adsorption treatment. Wastewaters from chemical industry that are rich in biodegradable organics are tested for anaerobic treatability. The efficiency of anaerobic reactor is relatively lower 79.3%, and therefore post treatment of effluent was done by adsorption using Poly vinyl alcohol coated Datura stramonium (PVAC-DS) as an adsorbent. An overall COD removal of 93.8 % was achieved after sequential Anaerobic-Adsorption treatment, which lead to a better final effluent and a more economical treatment system.

  1. POLISHING THE EFFLUENT FROM AN ANAEROBIC BIOLOGICAL PERCHLORATE TREATMENT PROCESS

    EPA Science Inventory

    Anaerobic biological processes effectively reduce perchlorate to chloride. However, the effluent can be biologically unstable, high in particulates and high in disinfection by-product precursor compounds. Such an effluent would be unsuitable for transmission into a drinking water...

  2. Bacterial ecology of abattoir wastewater treated by an anaerobic digestor

    PubMed Central

    Jabari, Linda; Gannoun, Hana; Khelifi, Eltaief; Cayol, Jean-Luc; Godon, Jean-Jacques; Hamdi, Moktar; Fardeau, Marie-Laure

    2016-01-01

    Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens), and msbl6 (candidate division) were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published. PMID:26887229

  3. Biodegradability of nitrogenous compounds under anaerobic conditions and its estimation.

    PubMed

    Hongwei, Yang; Zhanpeng, Jiang; Shaoqi, Shi

    2006-02-01

    The anaerobic biodegradability of 23 nitrogenous compounds, including nitrogenous heterocyclic compounds and aliphatic amines, was tested and assessed in integration. These nitrogenous compounds were classified into readily, partially, and poorly biodegradable compounds after calculation of their integrated assessment indices (IAIs), Rules for anaerobic biodegradation of these compounds were also drawn. Stepwise regression and backpropagation artificial neural network (BP-ANN) methods were applied to establish quantitative structure-biodegradability relationships (QSBRs) based on the assessment results. In QSBR models, three molecular structure descriptors-second-order molecular connectivity index (2chi(V3)chi(v)p), and energy of the highest occupied molecular orbital (EHOMO)--were included. After analysis of the sensitivity of variables in QSBR models, it was found that the key molecular structure descriptor affecting anaerobic biodegradability of nitrogenous compounds is EHOMO, which is directly proportional to the anaerobic biodegradability of nitrogenous compounds.

  4. Characteristics, process parameters, and inner components of anaerobic bioreactors.

    PubMed

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

    2014-01-01

    The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive.

  5. Comparison of microbial activity in anaerobic and microaerobic digesters.

    PubMed

    Jenicek, P; Celis, C A; Koubova, J; Pokorna, D

    2011-01-01

    Microaerobic alternative of anaerobic digestion offers many advantages especially when sulfide concentration in the digester is high. For better understanding of the microaerobic technology more detailed characterization of biomass activity is needed. Two equal digesters were operated under the same condition except of microaeration in one of them. During long term operation of anaerobic and microaerobic digesters the sludge quality and the biomass activity was monitored. The activity of sulfide oxidizing bacteria of microaerobic biomass was significantly higher in comparison with anaerobic biomass. The activity of sulfate reducing bacteria was comparable. The activity of methanogenic bacteria activity depended on sulfide concentration more than on microaeration. The extent of foaming problems was lower in the microaerobic than in the anaerobic digester.

  6. [Anaerobic growth ability and alcohol fermentation activity of microscopic fungi].

    PubMed

    Kurakov, A V; Khidirov, K S; Sadykova, V S; Zviagintsev, D G

    2011-01-01

    The method proposed in this study was used to isolate fungi grown under anaerobic conditions and to reveal distinctions in their abundance and species composition in different habitats. The ability of micromycetes of different taxa to grow under anaerobic conditions and ensure alcohol fermentation was determined for a representative sample (344 strains belonging to more than 60 species). The group of fungi growing under anaerobic conditions included species with high, moderate, and low fermentation activity. The ability for anaerobic growth and fermentation depended on the taxonomic affiliation of fungi. In some cases, the expression of these characteristics depended on the habitat from which the strain was isolated. The maximum level of ethanol accumulation in culture liquid (1.2-4.7%) was detected for Absidia spinosa, Aspergillus sp. of group flavus, Aspergillus terreus, Acremonium sp., Mucor circinelloides, Mucor sp., Fusarium oxysporum, F. solani, F. sambucinum, Rhizopus arrhizus var. Arrhizus, Trichoderma atroviride, and Trichoderma sp.

  7. Transparent Plastic Incubator for the Anaerobic Glove Box

    PubMed Central

    Balish, Edward; Brown, James F.; Wilkins, Tracy D.

    1977-01-01

    An incubator designed for use inside an anaerobic glove box is described. The incubator is made of transparent plastic material, has sliding plastic doors, and can be made in various sizes from readily available materials. Images PMID:16345202

  8. NATURAL BIOLOGICAL ATTENUATION OF AROMATIC HYDROCARBONS UNDER ANAEROBIC CONDITIONS

    EPA Science Inventory

    There is little consistent difference in the calculated half-lives of aromatic hydrocarbons in different anaerobic environments, but methanogenic environments might be generally the least supportive of rapid biotransformation. Toluene was usually the most rapidly biotransformed...

  9. Hydrogenosomes: convergent adaptations of mitochondria to anaerobic environments.

    PubMed

    Hackstein, J H; Akhmanova, A; Voncken, F; van Hoek, A; van Alen, T; Boxma, B; Moon-van der Staay, S Y; van der Staay, G; Leunissen, J; Huynen, M; Rosenberg, J; Veenhuis, M

    2001-01-01

    Hydrogenosomes are membrane-bound organelles that compartmentalise the final steps of energy metabolism in a number of anaerobic eukaryotes. They produce hydrogen and ATP. Here we will review the data, which are relevant for the questions: how did the hydrogenosomes originate, and what was their ancestor? Notably, there is strong evidence that hydrogenosomes evolved several times as adaptations to anaerobic environments. Most likely, hydrogenosomes and mitochondria share a common ancestor, but an unequivocal proof for this hypothesis is difficult because hydrogenosomes lack an organelle genome - with one remarkable exception (Nyctotherus ovalis). In particular, the diversity of extant hydrogenosomes hampers a straightforward analysis of their origins. Nevertheless, it is conceivable to postulate that the common ancestor of mitochondria and hydrogenosomes was a facultative anaerobic organelle that participated in the early radiation of unicellular eukaryotes. Consequently, it is reasonable to assume that both, hydrogenosomes and mitochondria are evolutionary adaptations to anaerobic or aerobic environments, respectively.

  10. Anaerobic psychrophiles from Lake Zub and Lake Untersee, Antarctica

    NASA Astrophysics Data System (ADS)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-08-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 μm. This new isolate is a mesophile with the maximum temperature of growth at 40°C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7 % (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3°C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18 °C, and growth at 22 °C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates

  11. Anaerobic Psychrophiles from Lake Zub and Lake Untersee, Antarctica

    NASA Technical Reports Server (NTRS)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-01-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 micron. This new isolate is a mesophile with the maximum temperature of growth at 40C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7% (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18C, and growth at 22C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates from

  12. The adaptive response of anaerobically grown Saccharomyces cerevisiae to hydrogen peroxide is mediated by the Yap1 and Skn7 transcription factors.

    PubMed

    Beckhouse, Anthony G; Grant, Chris M; Rogers, Peter J; Dawes, Ian W; Higgins, Vincent J

    2008-12-01

    The molecular mechanisms involved in the ability of cells to adapt and respond to differing oxygen tensions are of great interest to the pharmaceutical, medical and fermentation industries. The transcriptional profiles reported in previous studies of cells grown under anaerobic, aerobic and dynamic growth conditions have shown significantly altered responses including induction of genes regulated by the oxidative stress transcription factor Yap1p when oxygen was present. The present study investigated the phenotypic changes that occur in cells when shifted from anaerobic to aerobic growth conditions and it was found through mutant analyses that the elevated activity of Yap1p during the shift was mediated by the phospholipid hydroperoxide-sensing protein encoded by GPX3. Cell viability and growth rate were unaffected even though anaerobically grown cells were found to be hypersensitive to low doses of the oxidative stress-inducing compound hydrogen peroxide (H(2)O(2)). Adaptation to H(2)O(2) treatment was demonstrated to occur when anaerobically grown wild-type cells were aerated for a short time that was reliant on the Yap1p and Skn7p transcription factors.

  13. Modeling for Anaerobic Fixed-Bed Biofilm Reactors

    SciTech Connect

    Liu, B. Y. M.; Pfeffer, J. T.

    1989-06-01

    The specific objectives of this research were: 1. to develop an equilibrium model for chemical aspects of anaerobic reactors; 2. to modify the equilibrium model for non-equilibrium conditions; 3. to incorporate the existing biofilm models into the models above to study the biological and chemical behavior of the fixed-film anaerobic reactors; 4. to experimentally verify the validity of these models; 5. to investigate the biomass-holding ability of difference packing materials for establishing reactor design criteria.

  14. Dechlorination of Aromatic Xenobiotic Compounds by Anaerobic Microorganisms

    DTIC Science & Technology

    1988-07-01

    presence of thiosulfate, the formation of formic acid , succinic acid and several other intermediates by Day 28 suggests that bicarbonate is used during...Methane Sulfonic Acid (HS-CoM)- Atmosphere ." Appi. Environ. Microbiol. 3U:781-791. 91. Smith, M.R., S.H. Zinder, and R.A. Mah. 1980. "Microbial...anaerobic by flooding, adding an anaerobic atmosphere and/or adding readily degradable organic matter. Some of the soils were rice paddy soils

  15. Validity and reliability of the Hawaii anaerobic run test.

    PubMed

    Kimura, Iris F; Stickley, Christopher D; Lentz, Melissa A; Wages, Jennifer J; Yanagi, Kazuhiko; Hetzler, Ronald K

    2014-05-01

    This study examined the reliability and validity of the Hawaii anaerobic run test (HART) by comparing anaerobic capacity measures obtained to those during the Wingate Anaerobic Test (WAnT). Ninety-six healthy physically active volunteers (age, 22.0 ± 2.8 years; height, 163.9 ± 9.5 cm; body mass, 70.6 ± 14.7 kg; body fat %, 19.29 ± 5.39%) participated in this study. Each participant performed 2 anaerobic capacity tests: the WAnT and the HART by random assignment on separate days. The reliability of the HART was calculated from 2 separate trials of the test and then determined through intraclass correlation coefficients (ICCs). Blood samples were collected, and lactate was analyzed both pretest and posttest for each of the 2 exercise modes. Heart rate and rate of perceived exertion were also measured pre- and post-exercise. Hawaii anaerobic run test peak and mean momentum were calculated as body mass times highest or average split velocity, respectively. Intraclass correlation coefficients between trials of the HART for peak and mean momentum were 0.98 and 0.99, respectively (SEM = 18.8 and 25.7, respectively). Validity of the HART was established through comparison of momentum on the HART with power on the WAnT. High correlations were found between peak power and peak momentum (r = 0.88), as well as mean power and mean momentum (r = 0.94). The HART was considered to be a reliable test of anaerobic power. The HART was also determined to be a valid test of anaerobic power when compared with the WAnT. When testing healthy college-aged individuals, the HART offers an easy and inexpensive alternative maximal effort anaerobic power test to other established tests.

  16. Anaerobic digestion as a waste disposal option for American Samoa

    SciTech Connect

    Rivard, C

    1993-01-01

    Tuna sludge and municipal solid waste (MSW) generated on Tutuila Island, American Samoa, represent an ongoing disposal problem as well as an emerging opportunity for use in renewable fuel production. This research project focuses on the biological conversion of the organic fraction of these wastes to useful products including methane and fertilizer-grade residue through anaerobic high solids digestion. In this preliminary study, the anaerobic bioconversion of tuna sludge with MSW appears promising.

  17. Contribution of anaerobic energy expenditure to whole body thermogenesis

    PubMed Central

    Scott, Christopher B

    2005-01-01

    Heat production serves as the standard measurement for the determination of energy expenditure and efficiency in animals. Estimations of metabolic heat production have traditionally focused on gas exchange (oxygen uptake and carbon dioxide production) although direct heat measurements may include an anaerobic component particularly when carbohydrate is oxidized. Stoichiometric interpretations of the ratio of carbon dioxide production to oxygen uptake suggest that both anaerobic and aerobic heat production and, by inference, all energy expenditure – can be accounted for with a measurement of oxygen uptake as 21.1 kJ per liter of oxygen. This manuscript incorporates contemporary bioenergetic interpretations of anaerobic and aerobic ATP turnover to promote the independence of these disparate types of metabolic energy transfer: each has different reactants and products, uses dissimilar enzymes, involves different types of biochemical reactions, takes place in separate cellular compartments, exploits different types of gradients and ultimately each operates with distinct efficiency. The 21.1 kJ per liter of oxygen for carbohydrate oxidation includes a small anaerobic heat component as part of anaerobic energy transfer. Faster rates of ATP turnover that exceed mitochondrial respiration and that are supported by rapid glycolytic phosphorylation with lactate production result in heat production that is independent of oxygen uptake. Simultaneous direct and indirect calorimetry has revealed that this anaerobic heat does not disappear when lactate is later oxidized and so oxygen uptake does not adequately measure anaerobic efficiency or energy expenditure (as was suggested by the "oxygen debt" hypothesis). An estimate of anaerobic energy transfer supplements the measurement of oxygen uptake and may improve the interpretation of whole-body energy expenditure. PMID:15958171

  18. Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable.

    PubMed

    Sialve, Bruno; Bernet, Nicolas; Bernard, Olivier

    2009-01-01

    The potential of microalgae as a source of biofuels and as a technological solution for CO2 fixation is subject to intense academic and industrial research. In the perspective of setting up massive cultures, the management of large quantities of residual biomass and the high amounts of fertilizers must be considered. Anaerobic digestion is a key process that can solve this waste issue as well as the economical and energetic balance of such a promising technology. Indeed, the conversion of algal biomass after lipid extraction into methane is a process that can recover more energy than the energy from the cell lipids. Three main bottlenecks are identified to digest microalgae. First, the biodegradability of microalgae can be low depending on both the biochemical composition and the nature of the cell wall. Then, the high cellular protein content results in ammonia release which can lead to potential toxicity. Finally, the presence of sodium for marine species can also affect the digester performance. Physico-chemical pretreatment, co-digestion, or control of gross composition are strategies that can significantly and efficiently increase the conversion yield of the algal organic matter into methane. When the cell lipid content does not exceed 40%, anaerobic digestion of the whole biomass appears to be the optimal strategy on an energy balance basis, for the energetic recovery of cell biomass. Lastly, the ability of these CO2 consuming microalgae to purify biogas and concentrate methane is discussed.

  19. Structure and Dynamics of Anaerobic Bacterial Aggregates in a Gas-Lift Reactor

    PubMed Central

    Beeftink, H. H.; Staugaard, P.

    1986-01-01

    Anaerobic mixed-culture aggregates, which converted glucose to acetic, propionic, butyric, and valeric acids, were formed under controlled conditions of substrate feed (carbon limitation) and hydraulic regimen. The continuous-flow system used (anaerobic gas-lift reactor) was designed to retain bacterial aggregates in a well-mixed reactor. Carrier availability (i.e., liquid-suspended sand grains) proved necessary for bacterial aggregate formation from individual cells during reactor start-up. Electron microscopic examination revealed that incipient colonization of sand grains by bacteria from the bulk liquid occurred in surface irregularities, conceivably reflecting local quiescence. Subsequent confluent biofilm formation on sand grains proved to be unstable, however. Substrate depletion in the bulk liquid is assumed to weaken deeper parts of the biofilm due to cellular lysis, after which production of gas bubbles and liquid shearing forces cause sloughing. The resulting fragments, although sand free, were nevertheless large enough to be retained in the reactor and gradually grew larger through bacterial growth and by clumping together with other fragments. In the final steady state, high cell densities were maintained in the form of aggregates, while sand had virtually disappeared due to sampling losses and wash-out. Numerical cell densities within aggregates ranged from 1012/ml at the periphery to very low values in the center. The cells were enmeshed in a polymer matrix containing polysaccharides; nevertheless, carbon sufficiency was not a prerequisite to sustain high hold-up ratios. Images PMID:16347213

  20. Anaerobic treatment of effluents from an industrial polymers synthesis plant

    SciTech Connect

    Araya, P.; Aroca, G.; Chamy, R.

    1999-06-01

    The feasibility of the anaerobic treatment of an industrial polymer synthesis plant effluent was evaluated. The composition of the wastewater includes acrylates, styrene, detergents, a minor amount of silicates and a significant amount of ferric chloride. The average chemical oxygen demand (COD) corresponding is about 2,000 mg/l. The anaerobic biodegradability of the effluent is shown and the toxicity effect on the populations of anaerobic bacteria is evaluated. The results of the anaerobic biodegradation assays show that 62% of the wastewater compounds, measured as COD, could be consumed. An upflow anaerobic sludge blanket (UASB) reactor was used in the evaluation, it has a diameter-height ratio of 1:7, and 4-liter volume. The inoculum was obtained from a UASB pilot plant that treats brewery wastewaters. At the beginning of the operation, the biomass showed an anaerobic activity of 0.58 gCOD/(gVSS {times} d), it decreased only 2.5% in the subsequent 4 months. After 35 days of continuous operation, the reactor was operated at different steady states for 140 days. The COD was maintained at 2,200 mg/l in the feed. The results were: organic loading rate (OLR): 4.3 kg COD/(m{sup 3} {times} d), hydraulic retention time: 12 h, superficial velocity: 1 m/h, average biogas productivity: 290 L CH{sub 4}/kg COD fed, biogas composition: 70--75% methane and a COD removal percentage > 75%.

  1. Anaerobic biodegradation of (emerging) organic contaminants in the aquatic environment.

    PubMed

    Ghattas, Ann-Kathrin; Fischer, Ferdinand; Wick, Arne; Ternes, Thomas A

    2017-02-03

    Although strictly anaerobic conditions prevail in several environmental compartments, up to now, biodegradation studies with emerging organic contaminants (EOCs), such as pharmaceuticals and personal care products, have mainly focused on aerobic conditions. One of the reasons probably is the assumption that the aerobic degradation is more energetically favorable than degradation under strictly anaerobic conditions. Certain aerobically recalcitrant contaminants, however, are biodegraded under strictly anaerobic conditions and little is known about the organisms and enzymatic processes involved in their degradation. This review provides a comprehensive survey of characteristic anaerobic biotransformation reactions for a variety of well-studied, structurally rather simple contaminants (SMOCs) bearing one or a few different functional groups/structural moieties. Furthermore it summarizes anaerobic degradation studies of more complex contaminants with several functional groups (CMCs), in soil, sediment and wastewater treatment. While strictly anaerobic conditions are able to promote the transformation of several aerobically persistent contaminants, the variety of observed reactions is limited, with reductive dehalogenations and the cleavage of ether bonds being the most prevalent. Thus, it becomes clear that the transferability of degradation mechanisms deduced from culture studies of SMOCs to predict the degradation of CMCs, such as EOCs, in environmental matrices is hampered due the more complex chemical structure bearing different functional groups, different environmental conditions (e.g. matrix, redox, pH), the microbial community (e.g. adaptation, competition) and the low concentrations typical for EOCs.

  2. Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

    PubMed Central

    Mancini, Silvia A.; Ulrich, Ania C.; Lacrampe-Couloume, Georges; Sleep, Brent; Edwards, Elizabeth A.; Sherwood Lollar, Barbara

    2003-01-01

    Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors (ɛ) for carbon (range of −1.9 to −3.6‰) and hydrogen (range of −29 to −79‰) fractionation were observed during biodegradation of benzene under nitrate-reducing, sulfate-reducing, and methanogenic conditions. These differences are not related to differences in initial biomass or in rates of biodegradation. Carbon isotopic enrichment factors for anaerobic benzene biodegradation in this study are comparable to those previously published for aerobic benzene biodegradation. In contrast, hydrogen enrichment factors determined for anaerobic benzene biodegradation are significantly larger than those previously published for benzene biodegradation under aerobic conditions. A fundamental difference in the previously proposed initial step of aerobic versus proposed anaerobic biodegradation pathways may account for these differences in hydrogen isotopic fractionation. Potentially, C-H bond breakage in the initial step of the anaerobic benzene biodegradation pathway may account for the large fractionation observed compared to that in aerobic benzene biodegradation. Despite some differences in reported enrichment factors between cultures with different terminal-electron-accepting processes, carbon and hydrogen isotope analysis has the potential to provide direct evidence of anaerobic biodegradation of benzene in the field. PMID:12513995

  3. Using contaminated plants involved in phytoremediation for anaerobic digestion.

    PubMed

    Cao, Zewei; Wang, Shengxiao; Wang, Ting; Chang, Zhizhou; Shen, Zhenguo; Chen, Yahua

    2015-01-01

    This study investigated the anaerobic digestion capability of five plants and the effects of copper (Cu) and S,S'-ethylenediaminedisuccinic acid (EDDS, a chelator widely used in chelant-assisted phytoremediation) on biogas production to determine a feasible disposal method for plants used in remediation. The results showed that in addition to Phytolacca americana L., plants such as Zea mays L., Brassica napus L., Elsholtzia splendens Nakai ex F. Maekawa, and Oenothera biennis L. performed well in biogas production. Among these, O. biennis required the shortest period to finish anaerobic digestion. Compared to normal plants with low Cu content, the plants used in remediation with increased Cu levels (100 mg kg(-1)) not only promoted anaerobic digestion and required a shorter anaerobic digestion time, but also increased the methane content in biogas. When the Cu content in plants increased to 500, 1000, and 5000 mg kg(-1), the cumulative biogas production decreased by 12.3%, 14.6%, and 41.2%, respectively. Studies also found that EDDS conspicuously restrained biogas production from anaerobic digestion. The results suggest that anaerobic digestion has great potential for the disposal of contaminated plants and may provide a solution for the resource utilization of plants used in remediation.

  4. Effect of alkaline pretreatment on anaerobic digestion of solid wastes

    SciTech Connect

    Lopez Torres, M. Espinosa Llorens, Ma. del C.

    2008-11-15

    The introduction of the anaerobic digestion for the treatment of the organic fraction of municipal solid waste (OFMSW) is currently of special interest. The main difficulty in the treatment of this waste fraction is its biotransformation, due to the complexity of organic material. Therefore, the first step must be its physical, chemical and biological pretreatment for breaking complex molecules into simple monomers, to increase solubilization of organic material and improve the efficiency of the anaerobic treatment in the second step. This paper describes chemical pretreatment based on lime addition (Ca(OH){sub 2}), in order to enhance chemical oxygen demand (COD) solubilization, followed by anaerobic digestion of the OFMSW. Laboratory-scale experiments were carried out in completely mixed reactors, 1 L capacity. Optimal conditions for COD solubilization in the first step of pretreatment were 62.0 mEq Ca(OH){sub 2}/L for 6.0 h. Under these conditions, 11.5% of the COD was solubilized. The anaerobic digestion efficiency of the OFMSW, with and without pretreatment, was evaluated. The highest methane yield under anaerobic digestion of the pretreated waste was 0.15 m{sup 3} CH{sub 4}/kg volatile solids (VS), 172.0% of the control. Under that condition the soluble COD and VS removal were 93.0% and 94.0%, respectively. The results have shown that chemical pretreatment with lime, followed by anaerobic digestion, provides the best results for stabilizing the OFMSW.

  5. Fungal survival during anaerobic digestion of organic household waste.

    PubMed

    Schnürer, Anna; Schnürer, Johan

    2006-01-01

    Anaerobic digestion of organic waste yields energy rich biogas and retains nutrients (N, P, K, S, etc.) in a stabilised residue. For the residue to be used as a soil fertiliser, it must be free from pollutants and harmful microorganisms. Fungal survival during sanitation and anaerobic treatment of source-separated organic household waste and during aerobic storage of the residue obtained was investigated. Decimal reduction times were determined for inoculated fungi (Aspergillus flavus and Aspergillus fumigatus, Penicillium roqueforti, Rhizomucor pusillus, Thermoascus crustaceus and Thermomyces lanuginosus). Several different fungal species were found after waste sanitation treatment (70 degrees C, 1 h), with Aspergillus species dominating in non-inoculated waste. Anaerobic waste degradation decreased the diversity of fungal species for processes run at both 37 and 55 degrees C, but not total fungal colony forming units. Fungi surviving the mesophilic anaerobic digestion were mainly thermotolerant Talaromyces and Paecilomyces species. T. crustaceus and T. lanuginosus were the only inoculated fungi to survive the thermophilic anaerobic degradation process. Aerobic storage of both types of anaerobic residues for one month significantly decreased fungal counts.

  6. Decomposition of organic waste products under aerobic and anaerobic conditions

    SciTech Connect

    Gale, P.M.

    1988-01-01

    The objectives of this research were to determine the kinetics of C and N mineralization under aerobic and anaerobic conditions. These parameters were then used to verify the simulation model, DECOMPOSITION, for the anaerobic system. Incubation experiments were conducted to compare the aerobic and anaerobic decomposition of alfalfa (Medicago sativa L.), a substrate with a low C:N ratio. Under anaerobic conditions the net mineralization of N occurred more rapidly than that under aerobic conditions. However, the rate of C mineralization as measured by CO{sub 2} evolution was much lower. For the anaerobic decomposition of alfalfa, C mineralization was best described as the sum of the CO{sub 2} and CH{sub 4} evolved plus the water soluble organic C formed. The kinetics of C mineralization, as determined by this approach, were used to successfully predict the rate and amount of N mineralization from alfalfa undergoing anaerobic decomposition. The decomposition of paper mill sludge, a high C:N ratio substrate, was also evaluated.

  7. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    PubMed

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  8. Anaerobic bioventing of unsaturated zone contaminated with DDT and DNT.

    PubMed

    Shah, J K; Sayles, G D; Suidan, M T; Mihopoulos, P; Kaskassian, S

    2001-01-01

    Initial degradation of highly chlorinated compounds and nitroaromatic compounds found in munition waste streams is accelerated under anaerobic conditions followed by aerobic treatment of the degradation products. The establishment of anaerobic environment in a vadose zone can be accomplished by feeding appropriate anaerobic gas mixture, i.e., "anaerobic bioventing". The gas mixture contains an electron donor for the reduction of these compounds. Lab scale study was conducted to evaluate potential of anaerobic bioventing for the treatment of an unsaturated zone contaminated with 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and 2,4-dinitrotoluene (DNT). Hydrogen was used as the electron donor. Using the soil columns innoculate with anaerobic microorganisms, it was observed that by feeding a gas mixture of 1% hydrogen, 1% carbon dioxide and nitrogen, methanogenic conditions were established and DDT was reductively dechlorinated. 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) accumulated as the intermediate product. The half life of DDT was calculated to be 8.5 months. DNT completely disappeared after six months of operation and no intermediates could be detected.

  9. Hydrogen Biogeochemistry in Anaerobic and Photosynthetic Ecosystems

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The simple biochemistry of molecular hydrogen is central to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. In anoxic sediments, a great majority of microbial redox processes involve hydrogen as a reactant, product or potential by-product. Accordingly, the energetics (thermodynamics) of each of these processes is affected by variations in local H2 concentrations. It has long been established that this effect is important in governing microbe-microbe interactions and there are multiple demonstrations that "interspecies hydrogen transfer" can alter the products of, inhibit/stimulate, or even reverse microbial metabolic reactions. In anoxic sediments, H2 concentrations themselves are thought to be controlled by the thermodynamics of the predominant H2-consuming microbial process. In sediments from Cape Lookout Bight, this relationship quantitatively describes the co-variation of H2 concentrations with temperature (for methanogens and sulfate reducers) and with sulfate concentration (for sulfate reducers). The quantitative aspect is import= for two reasons: 1) it permits the modeling of H2-sensitive biogeochemistry, such as anaerobic methane oxidation or pathways of organic matter remineralization, as a function of environmental controls; 2) for such a relationship to be observed requires that intracellular biochemistry and bioenergetics are being directly expressed in a component of the extracellular medium. H2 could therefore be utilized a non-invasive probe of cellular energetic function in intact microbial ecosystems. Based on the latter principle we have measured down-core profiles of H2 and other relevant physico-chemical parameters in order to calculate the metabolic energy yields (DG) that support microbial metabolism in Cape Lookout Bight sediments. Methanogens in this system apparently function with energy yields significantly smaller than the minimum requirements suggested by pure

  10. Aminiphilus circumscriptus gen. nov., sp. nov., an anaerobic amino-acid-degrading bacterium from an upflow anaerobic sludge reactor.

    PubMed

    Díaz, C; Baena, S; Fardeau, M-L; Patel, B K C

    2007-08-01

    Strain ILE-2(T) was isolated from an upflow anaerobic sludge bed reactor treating brewery wastewater. The motile, non-sporulating, slightly curved cells (2-4 x 0.1 microm) stained Gram-negative and grew optimally at 42 degrees C and pH 7.1 with 0.5 % NaCl. The strain required yeast extract for growth and fermented Casamino acids, peptone, isoleucine, arginine, lysine, alanine, valine, glutamate, histidine, glutamine, methionine, malate, fumarate, glycerol and pyruvate to acetate, propionate and minor amounts of branched-chain fatty acids. Carbohydrates, formate, acetate, propionate, butyrate, isovalerate, methanol, ethanol, 1-propanol, butanol, lactate, succinate, starch, casein, gelatin, xylan and a number of other amino acids were not utilized. The DNA G+C content of strain ILE-2(T) was 52.7 mol%. 16S rRNA gene sequence analysis revealed that ILE-2(T) was distantly related to members of the genera Aminobacterium (83 % similarity) and Aminomonas (85 % similarity) in the family Syntrophomonadaceae, order Clostridiales, phylum Firmicutes. On the basis of the results of our polyphasic analysis, strain ILE-2(T) represents a novel species and genus within the family Syntrophomonadaceae, for which the name Aminiphilus circumscriptus gen. nov., sp. nov. is proposed. The type strain of Aminiphilus circumscriptus is ILE-2(T) (=DSM 16581(T) =JCM 14039(T)).

  11. Biogas plasticization coupled anaerobic digestion: continuous flow anaerobic pump test results.

    PubMed

    Schimel, Keith A; Boone, David R

    2010-03-01

    In this investigation, the Anaerobic Pump (TAP) and a conventional continuous flow stirred tank reactor (CFSTR) were tested side by side to compare performance. TAP integrates anaerobic digestion (AD) with biogas plasticization-disruption cycle to improve mass conversion to methane. Both prototypes were fed a "real world" 50:50 mixture of waste-activated sludge (WAS) and primary sludge and operated at room temperature (20 degrees Celsius). The quantitative results from three steady states show TAP peaked at 97% conversion of the particulate COD in a system hydraulic residence time (HRT) of only 6 days. It achieved a methane production of 0.32 STP cubic meter CH(4) per kilogram COD fed and specific methane yield of 0.78 m(3) CH(4) per cubic meter per day. This was more than three times the CFSTR specific methane yield (0.22 m(3) CH(4) per cubic meter per day) and more than double the CFSTR methane production (0.15 m(3) CH(4) per kilogram COD fed). A comparative kinetics analysis showed the TAP peak substrate COD removal rate (R (o)) was 2.24 kg COD per cubic meter per day, more than three times the CFSTR substrate removal rate of 0.67 kg COD per cubic meter per day. The three important factors contributing to the superior TAP performance were (1) effective solids capture (96%) with (2) mass recycle and (3) stage II plasticization-disruption during active AD. The Anaerobic Pump (TAP) is a high rate, high efficiency-low temperature microbial energy engine that could be used to improve renewable energy yields from classic AD waste substrates like refuse-derived fuels, treatment plant sludges, food wastes, livestock residues, green wastes and crop residuals.

  12. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

    PubMed

    Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  13. Transcriptomic evidence for net methane oxidation and net methane production in putative ANaerobic MEthanotrophic (ANME) archaea

    NASA Astrophysics Data System (ADS)

    Lloyd, K. G.; Alperin, M. J.; Teske, A.

    2010-12-01

    Anaerobic methane oxidation regulates methane emissions in marine sediments and is thought to be mediated by uncultured methanogen-like archaea collectively labeled ANME (for ANaerobic MEthanotrophs). ANME archaea are often assumed to be obligate methanotrophs that are incapable of net methanogenesis, and are therefore used as proxies for anaerobic methane oxidation in many environments in spite of uncertainty regarding their metabolic capabilities. We tested this assumption by detecting and quantifying methanogenic gene transcription of ANME archaea across clearly differentiated zones of methane oxidation vs. methane production in sediments from the White Oak River estuary, NC. ANME-1 archaea (a group of putative obligate methanotrophs) consistently transcribe 16S rRNA and mRNA of methyl coenzyme M reductase (mcrA) the key gene for methanogenesis, up to 45 cm into methanogenic sediments. CARD-FISH shows that ANME-1 archaea exist as single rod-shaped cells or pairs of cells, and in very low numbers. Integrating normalized depth-distributions of 16S rDNA and rRNA (measured with qPCR and RT-qPCR, respectively) shows that 26-77 % of the rDNA proxy for ANME-1 cell numbers, and 18-74 % of the rRNA proxy for ANME-1 activity occurs within methane-producing sediments. mRNA transcripts of dissimilatory sulfite reductase (dsrAB) from sulfate reducing bacteria, the putative syntrophic partners of sulfate-dependent methane oxidation, were amplified consistently from methane-oxidizing sediments, and inconsistently from methane-producing sediments. These results change the perspective from ANME-1 archaea as obligate methane oxidizers to methanogens that are also capable of methane oxidation.

  14. Impact of nano zero valent iron (NZVI) on methanogenic activity and population dynamics in anaerobic digestion.

    PubMed

    Yang, Yu; Guo, Jialiang; Hu, Zhiqiang

    2013-11-01

    Nano zero valent iron (NZVI), although being increasingly used for environmental remediation, has potential negative impact on methanogenesis in anaerobic digestion. In this study, NZVI (average size = 55 ± 11 nm) showed inhibition of methanogenesis due to its disruption of cell integrity. The inhibition was coincident with the fast hydrogen production and accumulation due to NZVI dissolution under anaerobic conditions. At the concentrations of 1 mM and above, NZVI reduced methane production by more than 20%. At the concentration of 30 mM, NZVI led to a significant increase in soluble COD (an indication of cell disruption) and volatile fatty acids in the mixed liquor along with an accumulation of H2, resulting in a reduction of methane production by 69% (±4% [standard deviation]). By adding a specific methanogenesis inhibitor-sodium 2-bromoethanesulfonate (BES) to the anaerobic sludge containing 30 mM NZVI, the amount of H2 produced was only 79% (±1%) of that with heat-killed sludge, indicating the occurrence of bacterially controlled hydrogen utilization processes. Quantitative PCR data was in accordance with the result of methanogenesis inhibition, as the level of methanogenic population (dominated by Methanosaeta) in the presence of 30 mM NZVI decreased significantly compared to that of the control. On the contrary, ZVI powder (average size <212 μm) at the same concentration (30 mM) increased methane production presumably due to hydrogenotrophic methanogenesis of hydrogen gas that was slowly released from the NZVI powder. While it is a known fact that NZVI disrupts cell membranes, which inhibited methanogenesis described herein, the results suggest that the rapid hydrogen production due to NZVI dissolution also contribute to methanogenesis inhibition and lead to bacterially controlled hydrogenotrophic processes.

  15. A Novel Electrophototrophic Bacterium Rhodopseudomonas palustris Strain RP2, Exhibits Hydrocarbonoclastic Potential in Anaerobic Environments

    PubMed Central

    Venkidusamy, Krishnaveni; Megharaj, Mallavarapu

    2016-01-01

    An electrophototrophic, hydrocarbonoclastic bacterium Rhodopseudomonas palustris stain RP2 was isolated from the anodic biofilms of hydrocarbon fed microbial electrochemical remediation systems (MERS). Salient properties of the strain RP2 were direct electrode respiration, dissimilatory metal oxide reduction, spore formation, anaerobic nitrate reduction, free living diazotrophy and the ability to degrade n-alkane components of petroleum hydrocarbons (PH) in anoxic, photic environments. In acetate fed microbial electrochemical cells, a maximum current density of 305 ± 10 mA/m2 (1000Ω) was generated (power density 131.65 ± 10 mW/m2) by strain RP2 with a coulombic efficiency of 46.7 ± 1.3%. Cyclic voltammetry studies showed that anaerobically grown cells of strain RP2 is electrochemically active and likely to transfer electrons extracellularly to solid electron acceptors through membrane bound compounds, however, aerobically grown cells lacked the electrochemical activity. The ability of strain RP2 to produce current (maximum current density 21 ± 3 mA/m2; power density 720 ± 7 μW/m2, 1000 Ω) using PH as a sole energy source was also examined using an initial concentration of 800 mg l-1 of diesel range hydrocarbons (C9-C36) with a concomitant removal of 47.4 ± 2.7% hydrocarbons in MERS. Here, we also report the first study that shows an initial evidence for the existence of a hydrocarbonoclastic behavior in the strain RP2 when grown in different electron accepting and illuminated conditions (anaerobic and MERS degradation). Such observations reveal the importance of photoorganotrophic growth in the utilization of hydrocarbons from contaminated environments. Identification of such novel petrochemical hydrocarbon degrading electricigens, not only expands the knowledge on the range of bacteria known for the hydrocarbon bioremediation but also shows a biotechnological potential that goes well beyond its applications to MERS. PMID:27462307

  16. A Novel Electrophototrophic Bacterium Rhodopseudomonas palustris Strain RP2, Exhibits Hydrocarbonoclastic Potential in Anaerobic Environments.

    PubMed

    Venkidusamy, Krishnaveni; Megharaj, Mallavarapu

    2016-01-01

    An electrophototrophic, hydrocarbonoclastic bacterium Rhodopseudomonas palustris stain RP2 was isolated from the anodic biofilms of hydrocarbon fed microbial electrochemical remediation systems (MERS). Salient properties of the strain RP2 were direct electrode respiration, dissimilatory metal oxide reduction, spore formation, anaerobic nitrate reduction, free living diazotrophy and the ability to degrade n-alkane components of petroleum hydrocarbons (PH) in anoxic, photic environments. In acetate fed microbial electrochemical cells, a maximum current density of 305 ± 10 mA/m(2) (1000Ω) was generated (power density 131.65 ± 10 mW/m(2)) by strain RP2 with a coulombic efficiency of 46.7 ± 1.3%. Cyclic voltammetry studies showed that anaerobically grown cells of strain RP2 is electrochemically active and likely to transfer electrons extracellularly to solid electron acceptors through membrane bound compounds, however, aerobically grown cells lacked the electrochemical activity. The ability of strain RP2 to produce current (maximum current density 21 ± 3 mA/m(2); power density 720 ± 7 μW/m(2), 1000 Ω) using PH as a sole energy source was also examined using an initial concentration of 800 mg l(-1) of diesel range hydrocarbons (C9-C36) with a concomitant removal of 47.4 ± 2.7% hydrocarbons in MERS. Here, we also report the first study that shows an initial evidence for the existence of a hydrocarbonoclastic behavior in the strain RP2 when grown in different electron accepting and illuminated conditions (anaerobic and MERS degradation). Such observations reveal the importance of photoorganotrophic growth in the utilization of hydrocarbons from contaminated environments. Identification of such novel petrochemical hydrocarbon degrading electricigens, not only expands the knowledge on the range of bacteria known for the hydrocarbon bioremediation but also shows a biotechnological potential that goes well beyond its applications to MERS.

  17. Some Aspects of Yeast Anaerobic Metabolism Examined by the Inhibition of Pyruvate Decarboxylase

    NASA Astrophysics Data System (ADS)

    Martin, Earl V.

    1998-10-01

    Incubation of yeast cells with various sugars in aqueous alkaline phosphate solutions under anaerobic conditions results in the accumulation of pyruvate in the cell medium after short periods of up to 15 minutes. This accumulation of pyruvate as the end product of glycolysis results from the inhibition of pyruvate decarboxylase under the conditions. This pyruvate production can be readily measured in the cell-free medium by a spectrophotometric assay using lactic dehydrogenase and NADH. The production of pyruvate can be directly related to the ability of the yeast cells to metabolize particular carbon sources provided. Comparison of pyruvate production by yeast from a variety of common sugars, for example, provides students with a means to assess what sugars are readily utilized by this organism. An additional advantage for student laboratory studies is the availability of Sacchromyces cerevisiae at minimal cost as dry granules which are easily weighed and quickly activated.

  18. Anaerobic biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by a facultative anaerobe Pseudomonas sp. JP1.

    PubMed

    Liang, Lei; Song, Xiaohui; Kong, Jing; Shen, Chenghui; Huang, Tongwang; Hu, Zhong

    2014-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are harmful persistent organic pollutants, while the high-molecular-weight (HMW) PAHs are even more detrimental to the environment and human health. However, microbial anaerobic degradation of HMW PAHs has rarely been reported. One facultative anaerobe Pseudomonas sp. JP1 was isolated from Shantou Bay, Shantou, China, which could degrade a variety of HMW PAHs. After 40 days cultivation with strain JP1, anaerobic biodegradation rate of benzo[a]pyrene (BaP), fluoranthene, and phenanthrene was 30, 47, and 5 %, respectively. Consumption of nitrate as the electron acceptor was confirmed by N-(1-naphthyl) ethylenediamine spectrophotometry. Supplementation of sodium sulfite, maltose, or glycine, and in a salinity of 0-20 ‰ significantly stimulated anaerobic degradation of BaP. Lastly, the anaerobic degradation metabolites of BaP by strain JP1 were investigated using GC/MS, and the degradation pathway was proposed. This study is helpful for further studies on the mechanism of anaerobic biodegradation of PAHs.

  19. Modified anaerobic digestion elutriated phased treatment for the anaerobic co-digestion of sewage sludge and food wastewater.

    PubMed

    Mo, Kyung; Lee, Wonbae; Kim, Moonil

    2017-02-01

    A modified anaerobic digestion elutriated phased treatment (MADEPT) process was developed for investigating anaerobic co-digestion of sewage sludge and food wastewater. The anaerobic digestion elutriated phased treatment (ADEPT) process is similar to a two-phase system, however, in which the effluent from a methanogenic reactor recycles into an acidogenic reactor to elutriate mainly dissolved organics. Although ADEPT could reduce reactor volume significantly, the unsolubilized solids should be wasted from the system. The MADEPT process combines thermo-alkali solubilization with ADEPT to improve anaerobic performance and to minimize the sludge disposal. It was determined that the optimal volume mixing ratio of sewage sludge and food wastewater was 4 : 1 for the anaerobic co-digestion. The removal efficiencies of total chemical oxygen demand, volatile solids, and volatile suspended solids in the MADEPT process were 73%, 70%, and 64%, respectively. However, those in the ADEPT process were only 48%, 37%, and 40%, respectively, at the same hydraulic retention time (HRT) of 7 days. The gas production of MADEPT was two times higher than that of ADEPT. The thermo-alkali solubilization increased the concentration of dissolved organics so that they could be effectively degraded in a short HRT, implying that MADEPT could improve the performance of ADEPT in anaerobic co-digestion.

  20. Thermal pretreatment of algae for anaerobic digestion.

    PubMed

    Marsolek, Michael D; Kendall, Elizabeth; Thompson, Phillip L; Shuman, Teodora Rutar

    2014-01-01

    The objective of this work was to determine the benefit of thermal pretreatment on biogas yield from microalgae-fed anaerobic digester mesocosms. Replicate Nanochloropsis oculata cultures were heated for 4h at 30, 60, and 90°C, as well as at a constant temperature of 90°C for 1, 3.5, and 12h. Net biogas production increased from 0.28L biogas/g volatile solids added (VSa) for the control to 0.39 L biogas/g VSa (p<0.01) when heated at 90°C, but there was no improvement at 30 or 60°C. Increased biogas production correlated with increased soluble chemical oxygen demand (COD). Net biogas production increased as a function of heating time, from 0.32 L biogas/g VSa for the control, to 0.41, 0.43, and 0.44 L biogas/g VSa (p<0.05 for all combinations vs. control) when preheated at 90°C for 1, 3.5, and 12h, respectively. However, despite enhanced biogas production the energy balance is negative for thermal pretreatment.

  1. Comparative anaerobic power of men and women.

    PubMed

    Murphy, M M; Patton, J F; Frederick, F A

    1986-07-01

    The purpose of this study was to determine the differences in anaerobic power (AnP) between men and women and the contribution of anthropometric variables in accounting for these differences. There were 18 female and 19 male subjects who performed the 30-s Wingate test where power outputs in watts are expressed as mean power (MP, the mean for 30 s) and peak power (PP, the highest 5-s interval). Thigh volume (TV), lean body mass (LBM) and body weight (BW) were used as anthropometric variables. Absolute AnP of men was 35% and 40% higher (p less than 0.001) than that of women for PP and MP, respectively. These differences decreased to 10% and 17% for PP and MP when expressed relative to kg LBM. Anthropometric variables explained less than 50% of the variation in PP and MP for men, while in women, TV accounted for 66% and 71% of the variation in PP and MP, respectively. When the data were combined, TV, BW, and LBM explained 48%, 74%, and 79% of variation in MP and 53%, 71%, and 76% in PP, respectively. These data show that gender differences in indices of AnP are similar to those reported for muscular strength and aerobic power. Additionally, a larger portion of the between gender variation compared to the within gender variation in AnP can be accounted for by anthropometric variables.

  2. Essential metal depletion in an anaerobic reactor.

    PubMed

    Osuna, M B; Iza, J; Zandvoort, M; Lens, P N L

    2003-01-01

    The effect of the absence of trace elements on the conversion of a mixture of volatile fatty acids by a distillery anaerobic granular sludge was investigated. Two UASB reactors were operated under identical operational conditions except for the influent trace metal concentrations, during 140 days. Experiments were carried out in three periods, where different organic loading rates (OLR) were applied to the reactors. The total trace metal concentration steadily decreased at a rate of 48 microg metal/g TS.d in the deprived reactor (down to 35% of their initial value). In contrast, trace metals accumulated in granules present in the control reactor. At the end of the experiment, the COD removal efficiencies were 99% and 77% for the control and deprived reactors, respectively, due to the lack of propionate conversion. Cobalt sorption experiments were carried out in order to study its speciation, and its effects on the speciation of other metals as well. A paper mill wastewater treating granular sludge was also included in the study as a comparison. Results obtained showed that the principal metal forms normally associated with any sludge are a function of each soluble metal concentration in the system, and the characteristics of the particular sludge.

  3. Anaerobic sludge digestion with a biocatalytic additive

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

  4. Anaerobic effluent disinfection using ozone: byproducts formation.

    PubMed

    Silva, G H R; Daniel, L A; Bruning, H; Rulkens, W H

    2010-09-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15 min. The wastewater used in this research was generated by the wastewater treatment plant (WWTP), University of São Paulo - Brazil. The total coliform inactivation range was 2.00-4.06 log(10), and the inactivation range for Escherichia coli was 2.41-4.65 log(10). Mean chemical oxygen demand (COD) reductions were 37.6%, 48.8% and 42.4% for doses of 5.0, 8.0 and 10.0mg O(3)L(-1), respectively. Aldehyde formation varied with dosage only when the ozone dose was increased from 5.0 to 8.0mg O(3)L(-1) for acetaldehyde and from 5.0 to 8.0 and from 8.0 to 10.0mg O(3)L(-1) for glyoxal.

  5. Parasite ova in anaerobically digested sludge

    SciTech Connect

    Arther, R.G.; Fitzgerald, P.R.; Fox, J.C.

    1981-08-01

    The Metropolitan Sanitary District of Greater Chicago produces anaerobically digested wastewater sludge from a 14-day continuous-flow process maintained at 35 degrees Celcius. Some of the sludge is ultimately applied to strip-mined lands in Central Illinois (Fulton County) as a soil conditioner and fertilizer. Parasitic nematode ova were isolated from freshly processed samples, as well as from samples collected from storage lagoons, using a system of continuous sucrose solution gradients. The mean number of ova per 100 g of dry sludge was 203 Ascaris spp., 173 Toxocara spp., 48 Toxascaris leonina, and 36 Trichuris spp. An assessment of the viability of these ova was determined by subjecting the ova to conditions favorable for embryonation. Recovered ova were placed in 1.5% formalin and aerated at 22 degrees Celcius for 21 to 28 days. Development of ova isolated from freshly digested sludge occurred in 64% of the Ascaris spp., 53% of the Toxocara, 63% of the Toxascaris leonina, and 20% of the Trichuris spp. Viability was also demonstrated in ova recovered from sludge samples held in storage lagoons for a period of up to 5 years; embryonation occurred in 24% of the Ascaris spp., 10% of the Toxocara spp., 43% of the Toxascaris leonina, and 6% of the Trichuris spp. (Refs. 24).

  6. Anaerobic degradation of linoleic oleic acids

    SciTech Connect

    Lalman, J.A.; Bagley, D.M.

    1999-07-01

    The anaerobic degradation of linoleic (C18:2) and oleic (C18:1) acids was examined in batch experiments. By-product distribution depended on both the type of long chain fatty acid added and initial substrate concentration. Major by-products were palmitic (C16), myristic (C14) and acetic acids. Trace quantities of palmitoleic (C16:1) and lauric (C12) acids were observed together with larger amounts of palmitic (C16), myristic (C14) and hexanoic (C6) acids in cultures incubated with 100 mg/L linoleic (C18:2) acid. Bio-hydrogenation of C18 fatty acids was not necessary for the {beta}-oxidation mechanism to proceed. Aceticlastic methanogenic inhibition was observed in cultures inoculated with greater than 50 mg/L linoleic (C18:2) acid. In cultures incubated with greater than 50 mg/L oleic (C18:1) acid, aceticlastic methanogenic inhibition was observed for a short time period.

  7. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils

    PubMed Central

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S. M.; Zhu, Guibing

    2017-01-01

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m−2 d−1), with anammox activities of 0.005–0.74 nmolN g−1 soil h−1, which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75–1.4 × 107 copies g−1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <103 copies g−1 soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known. PMID:28071702

  8. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils

    NASA Astrophysics Data System (ADS)

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S. M.; Zhu, Guibing

    2017-01-01

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m‑2 d‑1), with anammox activities of 0.005–0.74 nmolN g‑1 soil h‑1, which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75–1.4 × 107 copies g‑1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <103 copies g‑1 soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.

  9. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils.

    PubMed

    Wang, Shanyun; Radny, Dirk; Huang, Shuangbing; Zhuang, Linjie; Zhao, Siyan; Berg, Michael; Jetten, Mike S M; Zhu, Guibing

    2017-01-10

    Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN m(-2 )d(-1)), with anammox activities of 0.005-0.74 nmolN g(-1 )soil h(-1), which were even higher than the denitrification rates. By contrast, no significant anammox was measured in the vadose zone. Higher anammox bacterial cell densities were observed (0.75-1.4 × 10(7 )copies g(-1 )soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for anammox bacteria. The anammox bacterial cells in soils of the vadose zone were all <10(3 )copies g(-1 )soil. We suggest that the subsurface provides a favorable niche for anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.

  10. PAFC fed by biogas produced by the anaerobic fermentation of the waste waters of a beet-sugar refinery

    SciTech Connect

    Ascoli, A.; Elias, G.; Bigoni, L.; Giachero, R.

    1996-10-01

    Beet-washing waters of a beet-sugar refinery carry a high COD (Chemical Oxygen Demand), and their conditioning to meet legal constraints before disposal considerably contributes to the operation costs of the refinery. Their fermentation in an anaerobic digestor could instead produce readily disposable non-polluting waters, fertilizers and biogas, useful to feed a phosphoric acid fuel cell (PAFC) heat and power generator system. A real refinery case is considered in this work, where the electrical characteristics V = V(I) of a laboratory PAFC stack, fueled with a dry simulated reforming gas (having the same H{sub 2} and CO{sub 2} content as the biogas obtainable by the above said anaerobic digestion), are determined. The encouraging results show that a possible market niche for fuel cells, in the food-industry waste partial recovery and residual disposal, deserves attention.

  11. Robust and effective methodologies for cryopreservation and DNA extraction from anaerobic gut fungi.

    PubMed

    Solomon, Kevin V; Henske, John K; Theodorou, Michael K; O'Malley, Michelle A

    2016-04-01

    Cell storage and DNA isolation are essential to developing an expanded suite of microorganisms for biotechnology. However, many features of non-model microbes, such as an anaerobic lifestyle and rigid cell wall, present formidable challenges to creating strain repositories and extracting high quality genomic DNA. Here, we establish accessible, high efficiency, and robust techniques to store lignocellulolytic anaerobic gut fungi long term without specialized equipment. Using glycerol as a cryoprotectant, gut fungal isolates were preserved for a minimum of 23 months at -80 °C. Unlike previously reported approaches, this improved protocol is non-toxic and rapid, with samples surviving twice as long with negligible growth impact. Genomic DNA extraction for these isolates was optimized to yield samples compatible with next generation sequencing platforms (e.g. Illumina, PacBio). Popular DNA isolation kits and precipitation protocols yielded preps that were unsuitable for sequencing due to carbohydrate contaminants from the chitin-rich cell wall and extensive energy reserves of gut fungi. To address this, we identified a proprietary method optimized for hardy plant samples that rapidly yielded DNA fragments in excess of 10 kb with minimal RNA, protein or carbohydrate contamination. Collectively, these techniques serve as fundamental tools to manipulate powerful biomass-degrading gut fungi and improve their accessibility among researchers.

  12. Thermodynamic analysis of fermentation and anaerobic growth of baker's yeast for ethanol production.

    PubMed

    Teh, Kwee-Yan; Lutz, Andrew E

    2010-05-17

    Thermodynamic concepts have been used in the past to predict microbial growth yield. This may be the key consideration in many industrial biotechnology applications. It is not the case, however, in the context of ethanol fuel production. In this paper, we examine the thermodynamics of fermentation and concomitant growth of baker's yeast in continuous culture experiments under anaerobic, glucose-limited conditions, with emphasis on the yield and efficiency of bio-ethanol production. We find that anaerobic metabolism of yeast is very efficient; the process retains more than 90% of the maximum work that could be extracted from the growth medium supplied to the chemostat reactor. Yeast cells and other metabolic by-products are also formed, which reduces the glucose-to-ethanol conversion efficiency to less than 75%. Varying the specific ATP consumption rate, which is the fundamental parameter in this paper for modeling the energy demands of cell growth, shows the usual trade-off between ethanol production and biomass yield. The minimum ATP consumption rate required for synthesizing cell materials leads to biomass yield and Gibbs energy dissipation limits that are much more severe than those imposed by mass balance and thermodynamic equilibrium constraints.

  13. Influence of hydrothermal pretreatment on microalgal biomass anaerobic digestion and bioenergy production.

    PubMed

    Passos, Fabiana; Ferrer, Ivet

    2015-01-01

    Microalgal biomass grown in wastewater treatment raceway ponds may be valorised producing bioenergy through anaerobic digestion. However, pretreatment techniques seem to be necessary for enhancing microalgae methane yield. In this study, hydrothermal pretreatment was studied prior to batch and continuous reactors. The pretreatment increased organic matter solubilisation (8-13%), anaerobic digestion rate (30-90%) and final methane yield (17-39%) in batch tests. The highest increase was attained with the pretreatment at 130 °C for 15 min, which was attested in a laboratory-scale continuous reactor operated at a hydraulic retention time of 20 days with an average organic loading rate of 0.7 g VS/L·day. The methane yield increased from 0.12 to 0.17 L CH₄/g VS (41%) in the pretreated digester as compared to the control. Microscopic images of microalgal biomass showed that pretreated cells had unstructured organelles and disrupted cell wall external layer, which may enhance the hydrolysis. Indeed, images of the pretreated reactor digestate showed how cells were more degraded than in the control reactor.

  14. Anaerobic mesophilic treatment of cattle manure in an upflow anaerobic sludge blanket reactor with prior pasteurization.

    PubMed

    Marañón, Elena; Castrillón, Leonor; Fernández, Juan José; Fernández, Yolanda; Peláez, Ana Isabel; Sánchez, Jesús

    2006-02-01

    Different autonomous communities located in northern Spain have large populations of dairy cattle. In the case of Asturias, the greatest concentration of dairy farms is found in the areas near the coast, where the elimination of cattle manure by means of its use as a fertilizer may lead to environmental problems. The aim of the present research work was to study the anaerobic treatment of the liquid fraction of cattle manure at mesophilic temperature using an upflow anaerobic sludge blanket (UASB) reactor combined with a settler after a pasteurization process at 70 degrees C for 2 hr. The manure used in this study came from two different farms, with 40 and 200 cows, respectively. The manure from the smaller farm was pretreated in the laboratory by filtration through a 1-mm mesh, and the manure from the other farm was pretreated on the farm by filtration through a separator screw press (0.5-mm mesh). The pasteurization process removed the pathogenic microorganisms lacking spores, such as Enterococcus, Yersinia, Pseudomonas, and coliforms, but bacterial spores are only reduced by this treatment, not removed. The combination of a UASB reactor and a settler proved to be effective for the treatment of cattle manure. In spite of the variation in the organic loading rate and total solids in the influent during the experiment, the chemical oxygen demand (COD) of the effluent from the settler remained relatively constant, obtaining reductions in the COD of approximately 85%.

  15. Anaerobic treatment of distillery spent wash - a study on upflow anaerobic fixed film bioreactor.

    PubMed

    Acharya, Bhavik K; Mohana, Sarayu; Madamwar, Datta

    2008-07-01

    Anaerobic digestion of wastewater from a distillery industry having very high COD (1,10,000-1,90,000 mg/L) and BOD (50,000-60,000 mg/L) was studied in a continuously fed, up flow fixed film column reactor using different support materials such as charcoal, coconut coir and nylon fibers under varying hydraulic retention time and organic loading rates. The seed consortium was prepared by enrichment with distillery spent wash in a conventional type reactor having working capacity of 3 L and was used for charging the anaerobic column reactor. Amongst the various support materials studied the reactor having coconut coir could treat distillery spent wash at 8d hydraulic retention time with organic loading rate of 23.25 kg COD m(-3)d(-1) leading to 64% COD reduction with biogas production of 7.2 m3 m(-3)d(-1) having high methane yield without any pretreatment or neutralization of the distillery spent wash. This study indicates fixed film biomethanation of distillery spent wash using coconut coir as the support material appears to be a cost effective and promising technology for mitigating the problems caused by distillery effluent.

  16. Anaerobic respiration of Escherichia coli in the mouse intestine.

    PubMed

    Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

    2011-10-01

    The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

  17. Tellurite-, tellurate-, and selenite-based anaerobic respiration by strain CM-3 isolated from gold mine tailings.

    PubMed

    Maltman, Chris; Piercey-Normore, Michele D; Yurkov, Vladimir

    2015-09-01

    The newly discovered strain CM-3, a Gram-negative, rod-shaped bacterium from gold mine tailings of the Central Mine in Nopiming Provincial Park, Canada, is capable of dissimilatory anaerobic reduction of tellurite, tellurate, and selenite. CM-3 possesses very high level resistance to these oxides, both aerobically and anaerobically. During aerobic growth, tellurite and tellurate resistance was up to 1500 and 1000 µg/ml, respectively. In the presence of selenite, growth occurred at the highest concentration tested, 7000 µg/ml. Under anaerobic conditions, resistance was decreased to 800 µg/ml for the Te oxides; however, much like under aerobic conditions, growth with selenite still took place at 7000 µg/ml. In the absence of oxygen, CM-3 couples oxide reduction to an increase in biomass. Following an initial drop in viable cells, due to switching from aerobic to anaerobic conditions, there was an increase in CFU/ml greater than one order of magnitude in the presence of tellurite (6.6 × 10(3)-8.6 × 10(4) CFU/ml), tellurate (4.6 × 10(3)-1.4 × 10(5) CFU/ml), and selenite (2.7 × 10(5)-5.6 × 10(6) CFU/ml). A control culture without metalloid oxides showed a steady decrease in CFU/ml with no recovery. ATP production was also increased in the presence of each oxide, further indicating anaerobic respiration. Partial 16S rRNA gene sequencing revealed a 99.0 % similarity of CM-3 to Pseudomonas reactans.

  18. Acyl homoserine lactone-based quorum sensing stimulates biofilm formation by Salmonella Enteritidis in anaerobic conditions.

    PubMed

    Almeida, Felipe Alves de; Pimentel-Filho, Natan de Jesus; Pinto, Uelinton Manoel; Mantovani, Hilário Cuquetto; Oliveira, Leandro Licursi de; Vanetti, Maria Cristina Dantas

    2017-04-01

    Quorum sensing regulates a variety of phenotypes in bacteria including the production of virulence factors. Salmonella spp. have quorum sensing systems mediated by three autoinducers (AI-1, AI-2, and AI-3). The AI-1-mediated system is incomplete in that the bacterium relies on the synthesis of signaling molecules by other microorganisms. This study aimed to evaluate the influence of the AI-1 N-dodecanoyl-DL-homoserine lactone (C12-HSL) on the growth, motility, adhesion, and biofilm formation of Salmonella enterica serovar Enteritidis PT4 578 on a polystyrene surface. Experiments were conducted at 37 °C in anaerobic tryptone soy broth supplemented with C12-HSL and/or a mixture of four synthetic furanones, at the concentration of 50 nM each. The planktonic growth, adhesion, swarming, and twitching motility were not altered in the presence of C12-HSL and/or furanones under anaerobic conditions. However, C12-HSL induced biofilm formation after 36 h of cultivation as determined by quantification of biofilm formation, by enumeration of adhered cells to polystyrene coupons, and finally by imaging the presence of multilayered cells on an epifluorescence microscope. When furanones were present in the medium, an antagonistic effect against C12-HSL on the biofilm development was observed. The results demonstrate an induction of biofilm formation in Salmonella Enteritidis by AI-1 under anaerobic conditions. Considering that Salmonella does not produce AI-1 but respond to it, C12-HSL synthesized by other bacterial species could trigger biofilm formation by this pathogen in conditions that are relevant for its pathogenesis.

  19. Caffeine supplementation and peak anaerobic power output.

    PubMed

    Glaister, Mark; Muniz-Pumares, Daniel; Patterson, Stephen D; Foley, Paul; McInnes, Gillian

    2015-01-01

    The aim of this study was to investigate the effects of caffeine supplementation on peak anaerobic power output (Wmax). Using a counterbalanced, randomised, double-blind, placebo-controlled design, 14 well-trained men completed three trials of a protocol consisting of a series of 6-s cycle ergometer sprints, separated by 5-min passive recovery periods. Sprints were performed at progressively increasing torque factors to determine the peak power/torque relationship and Wmax. Apart from Trial 1 (familiarisation), participants ingested a capsule containing 5 mg·kg(-1) of caffeine or placebo, one hour before each trial. The effects of caffeine on blood lactate were investigated using capillary samples taken after each sprint. The torque factor which produced Wmax was not significantly different (p ≥ 0.05) between the caffeine (1.15 ± 0.08 N·m·kg(-1)) and placebo (1.13 ± 0.10 N·m·kg(-1)) trials. There was, however, a significant effect (p < 0.05) of supplementation on Wmax, with caffeine producing a higher value (1885 ± 303 W) than placebo (1835 ± 290 W). Analysis of the blood lactate data revealed a significant (p < 0.05) torque factor × supplement interaction with values being significantly higher from the sixth sprint (torque factor 1.0 N·m·kg(-1)) onwards following caffeine supplementation. The results of this study confirm previous reports that caffeine supplementation significantly increases blood lactate and Wmax. These findings may explain why the majority of previous studies, which have used fixed-torque factors of around 0.75 N·m·kg(-1) and thereby failing to elicit Wmax, have failed to find an effect of caffeine on sprinting performance.

  20. Anaerobic corrosion reaction kinetics of nanosized iron.

    PubMed

    Reardon, Eric J; Fagan, Randal; Vogan, John L; Przepiora, Andrzej

    2008-04-01

    Nanosized Fe0 exhibits markedly different anaerobic corrosion rates in water compared to that disseminated in moist quartz sand. In water, hydrogen production from corrosion exhibits an autocatalytic style, attaining a maximum rate of 1.9 mol kg(-1) d(-1) within 2 d of reaction. The rate then drops sharply over the next 20 d and enters a period of uniformly decreasing rate, represented equally well by first-order or diffusion-controlled kinetic expressions. In quartz sand, hydrogen production exhibits a double maximum over the first 20 d, similar to the hydration reaction of Portland cement, and the highest rate attained is less than 0.5 mol kg(-1) d(-1). We ascribe this difference in early time corrosion behavior to the ability of the released hydrogen gas to convect both water and iron particles in an iron/water system and to its inability to do so when the iron particles are disseminated in sand. By 30 d, the hydrogen production rate of iron in quartz sand exhibits a uniform decrease as in the iron/water system, which also can be described by first-order or diffusion-controlled kinetic expressions. However, the corrosion resistance of the iron in moist sand is 4 times greater than in pure water (viz. t1/2 of 365 d vs 78 d, respectively). The lower rate for iron in sand is likely due to the effect of dissolved silica sorbing onto iron reaction sites and acting as an anodic inhibitor, which reduces the iron's susceptibility to oxidation by water. This study indicates that short-term laboratory corrosion tests of nanosized Fe0/water slurries will substantially underestimate both the material's longevity as an electron source and its potential as a long-term source of hydrogen gas in groundwater remediation applications.

  1. Identification of Anaerobic Selenate-Respiring Bacteria from Aquatic Sediments▿

    PubMed Central

    Narasingarao, Priya; Häggblom, Max M.

    2007-01-01

    The diversity population of microorganisms with the capability to use selenate as a terminal electron acceptor, reducing it to selenite and elemental selenium by the process known as dissimilatory selenate reduction, is largely unknown. The overall objective of this study was to gain an in-depth understanding of anaerobic biotransformation of selenium in the environment, particularly anaerobic respiration, and to characterize the microorganisms catalyzing this process. Here, we demonstrate the isolation and characterization of four novel anaerobic dissimilatory selenate-respiring bacteria enriched from a variety of sources, including sediments from three different water bodies in Chennai, India, and a tidal estuary in New Jersey. Strains S5 and S7 from India, strain KM from the Meadowlands, NJ, and strain pn1, categorized as a laboratory contaminant, were all phylogenetically distinct, belonging to various phyla in the bacterial domain. The 16S rRNA gene sequence shows that strain S5 constitutes a new genus belonging to Chrysiogenetes, while strain S7 belongs to the Deferribacteres, with greater than 98% 16S rRNA gene similarity to Geovibrio ferrireducens. Strain KM is related to Malonomonas rubra, Pelobacter acidigallici, and Desulfuromusa spp., with 96 to 97% 16S rRNA gene similarity. Strain pn1 is 99% similar to Pseudomonas stutzeri. Strains S5, S7, and KM are obligately anaerobic selenate-respiring microorganisms, while strain pn1 is facultatively anaerobic. Besides respiring selenate, all these strains also respire nitrate. PMID:17435005

  2. Biochemical reaction engineering and process development in anaerobic wastewater treatment.

    PubMed

    Aivasidis, Alexander; Diamantis, Vasileios

    2005-01-01

    Developments in production technology have frequently resulted in the concentrated local accumulation of highly organic-laden wastewaters. Anaerobic wastewater treatment, in industrial applications, constitutes an advanced method of synthesis by which inexpensive substrates are converted into valuable disproportionate products. A critical discussion of certain fundamental principles of biochemical reaction engineering relevant to the anaerobic mode of operation is made here, with special emphasis on the roles of thermodynamics, kinetics, mass and heat transfer, reactor design, biomass retention and recycling. The applications of the anaerobic processes are discussed, introducing the principles of an upflow anaerobic sludge bed reactor and a fixed-bed loop reactor. The merits of staging reactor systems are presented using selected examples based on two decades of research in the field of anaerobic fermentation and wastewater treatment at the Forschungszentrum Julich (Julich Research Center, Germany). Wastewater treatment is an industrial process associated with one of the largest levels of mass throughput known, and for this reason it provides a major impetus to further developments in bioprocess technology in general.

  3. Anaerobic digestion for energy production and environmental protection

    SciTech Connect

    Lettinga, G.; Haandel, A.C. Vaan

    1993-12-31

    Anaerobic digestion is the decomposition of complex molecules into simpler substances by micro-organisms in the absence of oxygen. Anaerobic digestion processes can be employed for resource conservation, for the production of biogas and other useful end products from biomass, and for environmental protection through waste and wastewater treatment. Modern high-rate anaerobic wastewater-treatment processes can effectively remove organic pollutants from wastewater at a cost far below that of conventional aerobic processes. These anaerobic wastewater treatment processes can also be profitably applied for the generation of biogas from energy crops such as sugarcane. In fact, these methods might even be an attractive alternative for the alcohol fermentation extensively employed in Brazil for the production of fuel alcohol from sugarcane. The potential of modern anaerobic processes for this purpose has not yet been widely recognized. This paper describes the principles and use of these processes and demonstrates their prospects for producing energy from sugarcane (1) by treating vinasse, the wastewater generated during the production of ethanol from sugarcane, and (2) as a direct method for producing biogas from sugarcane juice.

  4. Anaerobic waste digestion in Germany--status and recent developments.

    PubMed

    Weiland, P

    2000-01-01

    Anaerobic treatment processes are especially suited for the utilization of wet organic wastes from agriculture and industry as well as for the organic part of source-separated household wastes. Anaerobic degradation is a very cost-effective method for treating biogenic wastes because the formed biogas can be used for heat and electricity production and the digester residues can be recycled to agriculture as a secondary fertilizer. Anaerobic technology will also be used for the common treatment of wastes together with renewable energy crops in order to reduce the CO2-emissions according the Kyoto protocol. Various process types are applied in Germany which differ in material, reaction conditions and in the form of the used reactor systems. The widespread introduction of anaerobic digestion in Germany has shown that biogenic organic wastes are a valuable source for energy and nutrients. Anaerobic waste treatment is done today in approx. 850 biogas plants on small farm scale as well as on large industrial scale with the best beneficial and economic outcome. Due to some new environmental protection acts which promote the recycling of wastes and their utilization for renewable energy formation it can be expected that several hundreds new biogas plants will be built per year in Germany. In order to use the synergetic effects of a combined fermentation of wastes and energy crops new process types must be developed in order to optimize the substrate combinations and the process conditions for maximum biodegradation.

  5. Potential nanosilver impact on anaerobic digestion at moderate silver concentrations.

    PubMed

    Yang, Yu; Chen, Qian; Wall, Judy D; Hu, Zhiqiang

    2012-03-15

    Silver nanoparticles (AgNPs, nanosilver) entering the sewers and wastewater treatment plants (WWTPs) are mostly accumulated in the sludge. In this study, we determined the impact of AgNPs on anaerobic glucose degradation, sludge digestion and methanogenic assemblages. At ambient (22 °C) and mesophilic temperatures (37 °C), there was no significant difference in biogas and methane production between the sludge treated with AgNPs at the concentrations up to 40 mg Ag/L (13.2 g silver/Kg biomass COD) and the control. In these anaerobic digestion samples, acetate and propionic acid were the only detectable volatile fatty acids (VFAs) and they were depleted in 3 days. On the other hand, more than 90% of AgNPs was removed from the liquid phase and associated with the sludge while almost no silver ions were released from AgNPs under anaerobic conditions. Quantitative PCR results indicated that Methanosaeta and Methanomicrobiales were the dominant methanogens, and the methanogenic diversity and population remained largely unchanged after nanosilver exposure and anaerobic digestion. The results suggest that AgNPs at moderate concentrations (e.g., ≤40 mg/L) have negligible impact on anaerobic digestion and methanogenic assemblages because of little to no silver ion release.

  6. Anaerobic bioleaching of metals from waste activated sludge.

    PubMed

    Meulepas, Roel J W; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal E; Lens, Piet N L

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g(-1) of copper, 487 μg g(-1) of lead, 793 μg g(-1) of zinc, 27 μg g(-1) of nickel and 2.3 μg g(-1) of cadmium. During the anaerobic acidification of 3 gdry weight L(-1) waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

  7. Anaerobic growth of a "strict aerobe" (Bacillus subtilis).

    PubMed

    Nakano, M M; Zuber, P

    1998-01-01

    There was a long-held belief that the gram-positive soil bacterium Bacillus subtilis is a strict aerobe. But recent studies have shown that B. subtilis will grow anaerobically, either by using nitrate or nitrite as a terminal electron acceptor, or by fermentation. How B. subtilis alters its metabolic activity according to the availability of oxygen and alternative electron acceptors is but one focus of study. A two-component signal transduction system composed of a sensor kinase, ResE, and a response regulator, ResD, occupies an early stage in the regulatory pathway governing anaerobic respiration. One of the essential roles of ResD and ResE in anaerobic gene regulation is induction of fnr transcription upon oxygen limitation. FNR is a transcriptional activator for anaerobically induced genes, including those for respiratory nitrate reductase, narGHJI.B. subtilis has two distinct nitrate reductases, one for the assimilation of nitrate nitrogen and the other for nitrate respiration. In contrast, one nitrite reductase functions both in nitrite nitrogen assimilation and nitrite respiration. Unlike many anaerobes, which use pyruvate formate lyase, B. subtilis can carry out fermentation in the absence of external electron acceptors wherein pyruvate dehydrogenase is utilized to metabolize pyruvate.

  8. Anaerobic biosynthesis of the lower ligand of vitamin B12

    PubMed Central

    Hazra, Amrita B.; Han, Andrew W.; Mehta, Angad P.; Mok, Kenny C.; Osadchiy, Vadim; Begley, Tadhg P.; Taga, Michiko E.

    2015-01-01

    Vitamin B12 (cobalamin) is required by humans and other organisms for diverse metabolic processes, although only a subset of prokaryotes is capable of synthesizing B12 and other cobamide cofactors. The complete aerobic and anaerobic pathways for the de novo biosynthesis of B12 are known, with the exception of the steps leading to the anaerobic biosynthesis of the lower ligand, 5,6-dimethylbenzimidazole (DMB). Here, we report the identification and characterization of the complete pathway for anaerobic DMB biosynthesis. This pathway, identified in the obligate anaerobic bacterium Eubacterium limosum, is composed of five previously uncharacterized genes, bzaABCDE, that together direct DMB production when expressed in anaerobically cultured Escherichia coli. Expression of different combinations of the bza genes revealed that 5-hydroxybenzimidazole, 5-methoxybenzimidazole, and 5-methoxy-6-methylbenzimidazole, all of which are lower ligands of cobamides produced by other organisms, are intermediates in the pathway. The bza gene content of several bacterial and archaeal genomes is consistent with experimentally determined structures of the benzimidazoles produced by these organisms, indicating that these genes can be used to predict cobamide structure. The identification of the bza genes thus represents the last remaining unknown component of the biosynthetic pathway for not only B12 itself, but also for three other cobamide lower ligands whose biosynthesis was previously unknown. Given the importance of cobamides in environmental, industrial, and human-associated microbial metabolism, the ability to predict cobamide structure may lead to an improved ability to understand and manipulate microbial metabolism. PMID:26246619

  9. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    SciTech Connect

    Samson, R.; LeDuy, A.

    1982-08-01

    The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

  10. Susceptibility testing of anaerobic bacteria: myth, magic, or method?

    PubMed Central

    Wexler, H M

    1991-01-01

    The demand for susceptibility testing of anaerobes has increased, yet consensus as to procedure and interpretation in this area has not been achieved. While routine testing of anaerobic isolates is not needed, certain isolates in specific clinical settings should be tested. Also, laboratories may monitor their local antibiograms by doing periodic surveillance batch testing. The National Committee for Clinical Laboratory Standards has published a protocol of methods approved for susceptibility testing of anaerobic bacteria. Both agar and broth microdilution are included; however, the broth disk elution method is no longer approved by the National Committee for Clinical Laboratory Standards because of method-related interpretive errors. A number of newer methods are undergoing evaluation and seem promising. Clinicians and microbiologists reviewing susceptibility reports should be aware of sources of variability in the test results. Variables in susceptibility testing of anaerobes include the media and methods used, organisms chosen for testing, breakpoints chosen for interpretation, antibiotic, and determination of endpoint. Clustering of MICs around the breakpoint may lead to significant variability in test results. Adherence of testing laboratories to approved methods and careful descriptions of the method and the breakpoints used for interpretation would facilitate interlaboratory comparisons and allow problems of emerging resistance to be noted. A variety of resistance mechanisms occurs in anaerobic bacteria, including the production of beta-lactamase and other drug-inactivating enzymes, alteration of target proteins, and inability of the drug to penetrate the bacterial wall. Antimicrobial resistance patterns in the United States and abroad are described. PMID:1747863

  11. Distinctive non-methanogen archaeal populations in anaerobic digestion.

    PubMed

    Chen, Si; He, Qiang

    2016-01-01

    Methanogens define the archaeal communities involved in anaerobic digestion. Recently, non-methanogen archaeal populations have been unexpectedly identified in anaerobic digestion processes. To gain insight into the ecophysiology of these uncharacterized archaeal populations, for the first time, a phylogenetic analysis was performed on a collection of non-methanogen archaeal 16S rRNA gene sequences from anaerobic digesters of broad geographic distribution, revealing a distinct clade formed by these sequences in subgroup 6 of the Miscellaneous Crenarchaeotal Group in the newly proposed archaeal phylum Bathyarchaeota. This exclusive phylogenetic assemblage enabled the development of a real-time quantitative PCR (qPCR) assay specifically targeting these non-methanogen archaeal populations in anaerobic digestion. Application of the qPCR assay in continuous anaerobic digesters indicated that these archaeal populations were minor constituents of the archaeal communities, and the abundance of these populations remained relatively constant irrespective of process perturbations. Analysis of the archaeal populations in methanogenic communities further revealed the co-occurrence of these non-methanogen archaea with acetoclastic methanogens. Nevertheless, the low abundance of non-methanogen archaea as compared with acetoclastic methanogens suggests that the non-methanogen archaeal populations were not major players in animal waste-fed methanogenic processes investigated in this study and the functions of these archaeal populations remain to be identified.

  12. Prevailing Torque Locking Feature in Threaded Fasteners Using Anaerobic Adhesive

    NASA Technical Reports Server (NTRS)

    Hernandez, Alan; Hess, Daniel P.

    2016-01-01

    This paper presents results from tests to assess the use of anaerobic adhesive for providing a prevailing torque locking feature in threaded fasteners. Test procedures are developed and tests are performed on three fastener materials, four anaerobic adhesives, and both unseated assembly conditions. Five to ten samples are tested for each combination. Tests for initial use, reuse without additional adhesive, and reuse with additional adhesive are performed for all samples. A 48-hour cure time was used for all initial use and reuse tests. Test data are presented as removal torque versus removal angle with the specification required prevailing torque range added for performance assessment. Percent specification pass rates for the all combinations of fastener material, adhesive, and assembly condition are tabulated and reveal use of anaerobic adhesive as a prevailing torque locking feature is viable. Although not every possible fastener material and anaerobic adhesive combination provides prevailing torque values within specification, any combination can be assessed using the test procedures presented. Reuse without additional anaerobic adhesive generally provides some prevailing torque, and in some cases within specification. Reuse with additional adhesive often provides comparable removal torque data as in initial use.

  13. Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria

    DTIC Science & Technology

    1977-01-15

    frawjilis A. Clinical distribution of subspecies at Boston City Hospital B. Prevalence of encapsulated strains within D. fragi1i• 3 C. The animal mcdel of...component of fecal flora (5,6). This subspecies prevalence appears to contrast with the distribution of subspecies in clinical infection where ss...Of interest has been the observation that the distribution of these subspecies in clinical infections is different from their relative prevalence in

  14. Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria.

    DTIC Science & Technology

    1976-01-15

    The lipopolysaccharides caused gelation of the Limulus lysate at a concentration significantly higher than that for the endotoxin of Salmonella typhi . None...endotoxin of Salmonella typhi induced this phenomenon at 3 ug per rabbit. Intact oxygen-killed B. fragilis failed to provoke the local Scwartzman reaction at

  15. Manipulating pyruvate to acetyl-CoA conversion in Escherichia coli for anaerobic succinate biosynthesis from glucose with the yield close to the stoichiometric maximum.

    PubMed

    Skorokhodova, Alexandra Yu; Morzhakova, Anastasiya A; Gulevich, Andrey Yu; Debabov, Vladimir G

    2015-11-20

    Efficient succinate production in Escherichia coli is attained during anaerobic glucose fermentation in biosynthetic processes combining the reductive branch of the TCA cycle and the glyoxylate bypass. Pyruvate dehydrogenase (PDH) or pyruvate formate lyase (PFL) serves in E. coli as a source of acetyl-CoA, a substrate for the glyoxylate bypass. Depending on enzymes responsible for acetyl-CoA generation, the contribution of the glyoxylate bypass to the anaerobic succinate biosynthesis may vary to support redox balance resulting in diverse maximum achievable yield values. Anaerobic succinate biosynthesis from glucose was studied using E. coli strains with altered expression of genes encoding PFL and PDH. For acetyl-CoA formation by PFL, the yield of 1.32 mol succinate per mole of glucose was achieved with the theoretical value of 1.6 mol/mol. Involvement of PDH in anaerobic acetyl-CoA synthesis increased succinate yield up to 1.49 mol/mol, which is 89.8% of the predicted maximum (1.6(6) mol/mol). The maximum yield of 1.69 mol succinate per mol glucose, amounting to 98.8% of the stoichiometric maximum (1.71 mol/mol), was achieved with the strain possessing PDH as the primary anaerobic source of acetyl-CoA. During high cell density fermentation, the best engineered strain produced high amounts of succinate (570.7 mM) and only small quantities of acetate (11.9 mM).

  16. Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

    PubMed

    Batstone, D J; Torrijos, M; Ruiz, C; Schmidt, J E

    2004-01-01

    The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter

  17. Clostridium thermoalcaliphilum sp. nov., an anaerobic and thermotolerant facultative alkaliphile.

    PubMed

    Li, Y; Engle, M; Weiss, N; Mandelco, L; Wiegel, J

    1994-01-01

    An anaerobic and thermophilic alkaliphile, strain JW/YL23-2T (T = type strain), was isolated from sewage sludge obtained from a sewage plant in Atlanta, Ga. At pH 10.1 and 50 degrees C, the doubling time of this strain was 19 min. Strain JW/YL23-2T, a motile rod-shaped bacterium with 2 to 12 peritrichous flagella, exhibited a negative Gram stain reaction but was gram-type positive as judged by the polymyxin B test. No heat-stable (85 degrees C, 15 min) endospores were detected. At 50 degrees C, growth occurred at pH values ranging from 7.0 to 11.0; the optimum pH was 9.6 to 10.1. The temperature range for growth ranged from 27 to 57.5 degrees C; the optimum temperature was 48 to 51 degrees C (pH 10.1). Dissimilatory sulfate reduction was not detected. The organism utilized glucose, fructose, sucrose, maltose, cellobiose, and Casamino Acids. The DNA G+C content was 32 mol% (as determined by chemical analysis). A 16S rRNA sequence analysis revealed a 2% inferred evolutionary distance to Clostridium paradoxum. However, the cell wall type of strain JW/YL23-2T was A4 beta (L-Orn-D-Asp), while that of C. paradoxum was A1 tau (m-diaminopimelic acid direct). On the basis of the alkaline pH values and high temperatures for optimal growth, the inability to form spores, and other characteristics different from C. paradoxum characteristics, strain JW/YL-23-2 was placed in a new species, Clostridium thermoalcaliphilum; JW/YL23-2 (= DSM 7309) is the type strain of this new species.

  18. Nitrogen loss by anaerobic oxidation of ammonium in rice rhizosphere

    PubMed Central

    Nie, San'an; Li, Hu; Yang, Xiaoru; Zhang, Zhaoji; Weng, Bosen; Huang, Fuyi; Zhu, Gui-Bing; Zhu, Yong-Guan

    2015-01-01

    Anaerobic oxidation of ammonium (anammox) is recognized as an important process for nitrogen (N) cycling, yet its role in agricultural ecosystems, which are intensively fertilized, remains unclear. In this study, we investigated the presence, activity, functional gene abundance and role of anammox bacteria in rhizosphere and non-rhizosphere paddy soils using catalyzed reporter deposition–fluorescence in situ hybridization, isotope-tracing technique, quantitative PCR assay and 16S rRNA gene clone libraries. Results showed that rhizosphere anammox contributed to 31–41% N2 production with activities of 0.33–0.64 nmol N2 g−1 soil h−1, whereas the non-rhizosphere anammox bacteria contributed to only 2–3% N2 production with lower activities of 0.08–0.26 nmol N2 g−1 soil h−1. Higher anammox bacterial cells were observed (0.75–1.4 × 107 copies g−1 soil) in the rhizosphere, which were twofold higher compared with the non-rhizosphere soil (3.7–5.9 × 106 copies g−1 soil). Phylogenetic analysis of the anammox bacterial 16S rRNA genes indicated that two genera of ‘Candidatus Kuenenia' and ‘Candidatus Brocadia' and the family of Planctomycetaceae were identified. We suggest the rhizosphere provides a favorable niche for anammox bacteria, which are important to N cycling, but were previously largely overlooked. PMID:25689022

  19. Pb(II) biosorption using anaerobically digested sludge.

    PubMed

    Tokcaer, Emre; Yetis, Ulku

    2006-10-11

    Removal of Pb(II) by using resting cells of anaerobically digested sludge (ADS) obtained from a nearby wastewater treatment plant was examined. Firstly, sorption kinetic and equilibrium experiments were conducted using agitated, thermostated (25 degrees C) batch reactors. The maximum Pb(II) sorption capacity was found to be very high (1,750 mg/g dry ADS or 8.45 mmol/g dry ADS). At all initial Pb(II) concentrations tested, sorption resulted in neutralization with an increase in the solution pH from an initial value of 4.0-5.5 to an equilibrium value of 7.0-8.0, at which Pb(II) can precipitate as hydroxide. The removal of Pb(II) by ADS was found to involve bioprecipitation as well as biosorption. FTIR spectrometry highlighted carboxyl groups present on the surface of ADS as the major functional groups responsible for biosorption. Secondly, a three-stage semi-continuous pseudo-counter current reactor system was tested to reduce ADS requirement in comparison to a conventional single-stage batch reactor. At an initial Pb(II) concentration of about 200 mg/L, an effluent Pb(II) concentration of 1.3 mg/L was achieved in the three stage reactor, corresponding to a metal removal capacity of 682.7 mg/g dry ADS (3.30 mmol/g), in comparison to 1.9 mg/L and 644.0 mg/g dry ADS (3.10 mmol/g) for the single-stage batch reactor.

  20. Clostridium thermoalcaliphilum sp. nov., an anaerobic and thermotolerant facultative alkaliphile

    SciTech Connect

    Youhong Li; Engle, M.; Wiegel, J.

    1994-01-01

    An anaerobic and thermophilic alkaliphile, strain JW/YL23-2{sub T} (T = type strain), was isolated from sewage sludge obtained from a sewage plant in Atlanta, Ga. at pH 10.1 and 50{degrees}C, the doubling time of this strain was 19 min. Strain JW/YL23-2{sub T}, a motile rod-shaped bacterium with 2 to 12 peritrichous flagella, exhibited a negative Gram stain reaction but was gram-type positive as judged by the polymyxin B test. No heat-stable (85{degrees}C, 15 min) endospores were detected. At 50{degrees}C, growth occurred at pH values ranging from 7.0 to 11.0; the optimum pH was 9.6 to 10.1. The temperature range for growth ranged from 27 to 57.5{degrees}C; the optimum temperature was 48 to 51{degrees}C (pH 10.1). Dissimilatory sulfate reduction was not detected. The organism utilized glucose, fructose, sucrose, maltose, cellobiose, and Casamino Acids. The DNA G+C content was 32 mol% (as determined by chemical analysis). A 16S rRNA sequence analysis revealed a 2% inferred evolutionary distance to Clostridium paradoxum. However, the cell wall type of strain JW/YL23-2{sup T} was A4{beta} (L-Orn-D-Asp), while that of C. paradoxum was Al{sub {tau}} (m-diaminopimelic acid direct). On the basis of the alkaline pH values and high temperatures for optimal growth, the inability to form spores, and other characteristics different from C. paradoxum characteristics, strain JW/YL-23-2 was placed in a new species, Clostridium thermoalcaliphilum; JW/YL23-2 (= DSM 7309) is the type strain of this new species.

  1. Effect of respiratory warm-up on anaerobic power.

    PubMed

    Özdal, Mustafa; Bostanci, Özgür; Dağlioğlu, Önder; Ağaoğlu, Seydi Ahmet; Kabadayi, Menderes

    2016-07-01

    [Purpose] The aim of the present study was to examine the effects of respiratory muscle warm-up on anaerobic power. [Subjects and Methods] Thirty male field hockey players (age, 20.5 ± 2.0 years) each participated in a control (CAN) trial and an experimental (EAN) trial. The EAN trial involved respiratory muscle warm-up, while the CAN trial did not. Anaerobic power was measured using the Wingate protocol. Paired sample t-tests were used to compare the EAN and CAN trials. [Results] There were significant increases in peak power and relative peak power, and decreases in the time to peak after the EAN trial by 8.9%, 9.6%, and 28.8% respectively. [Conclusion] Respiratory muscle warm-up may positively affect anaerobic power due to faster attainment of peak power.

  2. Defining Anaerobic Digestion Stability-Full Scale Study

    NASA Astrophysics Data System (ADS)

    Demitry, M. E., Sr.

    2014-12-01

    A full-scale anaerobic digester receiving a mixture of primary and secondary sludge was monitored for one hundred days. A chemical oxygen demand, COD, and a volatile solids, VS, mass balance was conducted to evaluate the stability of the digester and its capability of producing methane gas. The COD mass balance could account for nearly 90% of the methane gas produced while the VS mass balance showed that 91% of the organic matter removed resulted in biogas formation. Other parameters monitored included: pH, alkalinity, VFA, and propionic acid. The values of these parameters showed that steady state had occurred. Finally, at mesophilic temperature and at steady state performance, the anaerobic digester stability was defined as a constant ratio of methane produced per substrate of ΔVS (average ratio=0.404 l/g). This ratio can be used as universal metric to determine the anaerobic digester stability in an easy and inexpensive way.

  3. Microbiology and physiology of anaerobic fermentations of cellulose

    SciTech Connect

    Wiegel, J.

    1991-05-01

    The biochemistry and physiology of four major groups of anaerobic bacteria involved in the conversion of cellulose to methane or chemical feedstocks are examined. Aspects of metabolism which are relevant to the interactions and bioenergetics of consortia are being studied. Properties of the cellulolytic enzyme cluster of Clostridium thermocellum are investigated. Five different hydrogenases have been characterized in detail from anaerobic bacteria. Genes for different hydrogenases are being cloned and sequenced to determine their structural relationships. The role of metal clusters in activation of H{sub 2} is being investigated, as is the structure and role of metal clusters in formate metabolism. The function of formate in the total synthesis of acetate from CO{sub 2} and the role of this primary in anaerobes will be examined as well. Finally, these enzyme studies will be performed on thermophilic bacteria and new, pertinent species will be isolated. 50 refs., 3 figs., 1 tab.

  4. Anaerobic digestion of microalgal biomass: Challenges, opportunities and research needs.

    PubMed

    Gonzalez-Fernandez, Cristina; Sialve, Bruno; Molinuevo-Salces, Beatriz

    2015-12-01

    Integration of anaerobic digestion (AD) with microalgae processes has become a key topic to support economic and environmental development of this resource. Compared with other substrates, microalgae can be produced close to the plant without the need for arable lands and be fully integrated within a biorefinery. As a limiting step, anaerobic hydrolysis appears to be one of the most challenging steps to reach a positive economic balance and to completely exploit the potential of microalgae for biogas and fertilizers production. This review covers recent investigations dealing with microalgae AD and highlights research opportunities and needs to support the development of this resource. Novel approaches to increase hydrolysis rate, the importance of the reactor design and the noteworthiness of the microbial anaerobic community are addressed. Finally, the integration of AD with microalgae processes and the potential of the carboxylate platform for chemicals and biofuels production are reviewed.

  5. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    USGS Publications Warehouse

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  6. Effect of respiratory warm-up on anaerobic power

    PubMed Central

    Özdal, Mustafa; Bostanci, Özgür; Dağlioğlu, Önder; Ağaoğlu, Seydi Ahmet; Kabadayi, Menderes

    2016-01-01

    [Purpose] The aim of the present study was to examine the effects of respiratory muscle warm-up on anaerobic power. [Subjects and Methods] Thirty male field hockey players (age, 20.5 ± 2.0 years) each participated in a control (CAN) trial and an experimental (EAN) trial. The EAN trial involved respiratory muscle warm-up, while the CAN trial did not. Anaerobic power was measured using the Wingate protocol. Paired sample t-tests were used to compare the EAN and CAN trials. [Results] There were significant increases in peak power and relative peak power, and decreases in the time to peak after the EAN trial by 8.9%, 9.6%, and 28.8% respectively. [Conclusion] Respiratory muscle warm-up may positively affect anaerobic power due to faster attainment of peak power. PMID:27512273

  7. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth

  8. Model selection, identification and validation in anaerobic digestion: a review.

    PubMed

    Donoso-Bravo, Andres; Mailier, Johan; Martin, Cristina; Rodríguez, Jorge; Aceves-Lara, César Arturo; Vande Wouwer, Alain

    2011-11-01

    Anaerobic digestion enables waste (water) treatment and energy production in the form of biogas. The successful implementation of this process has lead to an increasing interest worldwide. However, anaerobic digestion is a complex biological process, where hundreds of microbial populations are involved, and whose start-up and operation are delicate issues. In order to better understand the process dynamics and to optimize the operating conditions, the availability of dynamic models is of paramount importance. Such models have to be inferred from prior knowledge and experimental data collected from real plants. Modeling and parameter identification are vast subjects, offering a realm of approaches and methods, which can be difficult to fully understand by scientists and engineers dedicated to the plant operation and improvements. This review article discusses existing modeling frameworks and methodologies for parameter estimation and model validation in the field of anaerobic digestion processes. The point of view is pragmatic, intentionally focusing on simple but efficient methods.

  9. My Lifelong Passion for Biochemistry and Anaerobic Microorganisms.

    PubMed

    Thauer, Rudolf Kurt

    2015-01-01

    Early parental influence led me first to medical school, but after developing a passion for biochemistry and sensing the need for a deeper foundation, I changed to chemistry. During breaks between semesters, I worked in various biochemistry labs to acquire a feeling for the different areas of investigation. The scientific puzzle that fascinated me most was the metabolism of the anaerobic bacterium Clostridium kluyveri, which I took on in 1965 in Karl Decker's lab in Freiburg, Germany. I quickly realized that little was known about the biochemistry of strict anaerobes such as clostridia, methanogens, acetogens, and sulfate-reducing bacteria and that these were ideal model organisms to study fundamental questions of energy conservation, CO2 fixation, and the evolution of metabolic pathways. My passion for anaerobes was born then and is unabated even after 50 years of study.

  10. [Tinidazole: a classical anaerobical drug with multiple potential uses nowadays].

    PubMed

    Granizo, J J; Pía Rodicio, M; Manso, F J; Giménez, Ma José

    2009-06-01

    Tinidazole is a 5-nitroimidazole active in vitro against a wide variety of anaerobic bacteria and protozoa. Tinidazole is an effective treatment against anaerobic microorganisms based on its pharmacokinetic characteristics (C(max) 51 microg/ml, t(1/2) 12.5 h) and its excellent in vitro activity. Its long half-life allows once a day regimens. Tinidazole is as effective as metronidazole in the treatment of infections caused by T. vaginalis, giardiasis and amebiasis and bacterial vaginosis, malaria, odontogenic infections, anaerobic bacterial infections (pelvic inflammatory disease, diabetic foot), surgical prophylaxis (abdominal and hysterectomy) and Helicobacter pylori eradication. Tinidazole was recently approved by the Food and Drug Administration (FDA) for the treatment of infections caused by Trichomonas vaginalis, Entamoeba histolytica and Giardia lamblia.

  11. Anaerobic Biotransformation and Mobility of Pu and PuEDTA

    SciTech Connect

    Xun, Luying

    2005-06-01

    Although our goal is to isolate anaerobic EDTA degraders, we initiated the experiments to include nitrilotriacetate (NTA), which is a structure homologue of EDTA. All the aerobic EDTA degraders can degrade NTA, but the isolated