Sample records for anaerobic phototrophic bacteria

  1. Experimental modelling of Calcium carbonate precipitation in the presence of phototrophic anaerobic bacteria Rhodovulum sp. (United States)

    Bundeleva, Irina; Shirokova, Liudmila; Benezeth, Pascale; Pokrovsky, Oleg; Kompantseva, Elena


    Carbonate biomineralization is considered as one of the main natural processes controlling CO2 levels in the atmosphere both in the past and at present time. Haloalcaliphilic Rhodovulum sp. A-20s isolated from soda lake in southern Siberia and halophilic neutrophilic Rhodovulum sp. S-1765 isolated from hypersaline water body in Crimea steppe represent a large group of phototrophic bacteria likely to be involved in CaCO3 formation in soda and saline lakes. These bacteria use organic substrates for non-oxygenic photosynthesis and thus may mediate CaCO3 precipitation without CO2 consumption in highly-saline, highly-alkaline, NaHCO3-rich solutions. In order to provide the link between surface properties of bacteria and their ability to precipitate Ca carbonate, we used a combination of electrophoretic mobility measurements, surface titration and Ca ion adsorption using dead (autoclaved), inactivated (NaN3 - treated) and live cells at 25 °C as a unction of pH (3-11) and NaCl concentrations (0.01, 0.1, 0.5 M). Zeta potential of both bacteria is identical for active, NaN3-inactivated and dead cells at high ionic strength (0.5 M NaCl). The pH of isoelectric point is below 3 and zeta-potential decreases or remain negative up to pH 11. However, at lower ionic strength (0.1 M and 0.01 M NaCl) for live cells the potential increases towards positive values in the alkaline solutions (pH of 9 to 10). Similar to previous results on cyanobacteria (Martinez et al., 2009) there is a net increase in zeta-potential towards more positive values at pH = 10.4 for active cells. In order to better understand this phenomenon, experiments with different concentration of Ca2+ and HCO3- ions as well as experiments with live cultures in the darkness have been carried out. The presence in solution of Ca2+ (0.01 and 0.001 M) and the absence of light in experiment do not change significantly the potential of the cells. However, the presence in solution of HCO3- strongly reduces the zeta

  2. Phototrophic bacteria and their role in the biogeochemical sulfur cycle (United States)

    Trueper, H. G.


    An essential step that cannot be bypassed in the biogeochemical cycle of sulfur today is dissimilatory sulfate reduction by anaerobic bacteria. The enormous amounts of sulfides produced by these are oxidized again either anaerobically by phototrophic bacteria or aerobically by thiobacilli and large chemotrophic bacteria (Beggiatoa, Thiovulum, etc.). Phototrophic bacteria use sulfide, sulfur, thiosulfate, and sulfite as electron donors for photosynthesis. The most obvious intermediate in their oxidative sulfur metabolism is a long chain polysulfide that appears as so called sulfur globules either inside (Chromatiaceae) or outside (Ectothiorhodospiraceae, Chlorobiaceae, and some of the Rhodospirillaceae) the cells. The assimilation of sulfur compounds in phototrophic bacteria is in principle identical with that of nonphototrophic bacteria. However, the Chlorobiaceae and some of the Chromatiaceae and Rhodospirillaceae, unable to reduce sulfate, rely upon reduced sulfur for biosynthetic purposes.

  3. Anaerobic bacteria (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  4. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane


    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

  5. Aerobic anoxygenic phototrophic bacteria and their roles in marine ecosystems

    Institute of Scientific and Technical Information of China (English)


    Aerobic anoxygenic phototrophic bacteria (AAPB) are characterized by the following physiological and ecological features. A mother AAPB cell can unusually divide into 3 daughter cells and looks like a "Y" during the division. AAPB cells sometimes adhere together forming a free-floating population. Most of the known AAPB species are obligately aerobic. Bacteriochlorophyll a (BChl a) is the only photosynthetic pigment in AAPB, and the number of BChl a molecules in an AAPB cell is much less than that in an anaerobic phototrophic bacterial cell, while the accessorial pigments carotenoids in AAPB are abundant in concentration and diverse in species. In addition to the common magnesium containing BChl a, a zinc-containing BChla was also seen in AAPB. AAPB have light harvesting complexⅠbut usually lack light harvesting complexⅡ. Although AAPB featur in photosynthesis, their growth is not necessarily light- dependent. There is a mechanism controlling the photosynthesis approach. AAPB are widely distributed in marine environments especially in oligotrophic oceans accounting for a substantial portion of the total biomass and playing a unique role in the cycle of carbon and other biogenic elements. Besides the contribution to primary production, AAPB also have great potentials in bioremediation of polluted environments. Studies on AAPB would be of great value in understanding the evolution of photosynthesis and the structure and function of marine ecosystems.

  6. Buoyant densities of phototrophic sulfur bacteria and cyanobacteria (United States)

    Guerrero, R.


    The buoyant densities of bacterial cells are greatly influenced by the accumulation of intracellular reserve material. The buoyant density of phototrophic bacteria that are planktonic is of particular interest, since these organisms must remain in the photic zone of the water column for optimal growth. Separation of cells by their buoyant density may also be of use in separating and identifying organisms from a natural population. The bacteria used were obtained from pure cultures, enrichments, or samples taken directly from the environment.

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

    KAUST Repository

    Shoener, B. D.


    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 3400-13000 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 phototrophic

  8. Anaerobic bacteria in otitis media. (United States)

    Fulghum, R S; Daniel, H J; Yarborough, J G


    Anaerobic bacteria, Peptostrepotococcus intermedius and Propionibacterium acnes, were found in mixed culture specimens from four to ten tested cases of chronic secretory otitis media. These anaerobic bacteria were in a mixed infection flora with aerobic bacteria most often Staphylococcus epidermidis and Cornybacterium sp. which do not fit any established species. The findings of anaerobic bacteria in otitis media is consistent with the sporadic report of the involvement of anaerobic bacteria in otitis media in the literature since 1898.

  9. Phylogenetically Diverse Aerobic Anoxygenic Phototrophic Bacteria Isolated from Epilithic Biofilms in Tama River, Japan (United States)

    Hirose, Setsuko; Matsuura, Katsumi; Haruta, Shin


    The diversity of aerobic anoxygenic phototrophic (AAP) bacteria in freshwater environments, particularly in rivers, has not been examined in as much detail as in ocean environments. In the present study, we investigated the phylogenetic and physiological diversities of AAP bacteria in biofilms that developed on submerged stones in a freshwater river using culture methods. The biofilms collected were homogenized and inoculated on solid media and incubated aerobically in the dark. Sixty-eight red-, pink-, yellow-, orange-, or brown-colored colonies were isolated, and, of these, 28 isolates contained the photosynthetic pigment, bacteriochlorophyll (BChl) a. Phylogenetic analyses based on 16S rRNA gene sequences showed that the isolates were classified into 14 groups in 8 operational taxonomic units (OTUs) and distributed in the orders Rhodospirillales, Rhodobacterales, and Sphingomonadales of Alphaproteobacteria and in Betaproteobacteria. Physiological analyses confirmed that none of the representative isolates from any of the groups grew under anaerobic phototrophic conditions. Seven isolates in 4 OTUs showed a 16S rRNA gene sequence identity of 98.0% or less with any established species, suggesting the presence of previously undescribed species of AAP bacteria. Six isolates in 2 other OTUs had the closest relatives, which have not been reported to be AAP bacteria. Physiological comparisons among the isolates revealed differences in preferences for nutrient concentrations, BChl contents, and light-harvesting proteins. These results suggest that diverse and previously unknown AAP bacteria inhabit river biofilms. PMID:27453124

  10. Method for quantification of aerobic anoxygenic phototrophic bacteria

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao; JIAO Nianzhi


    Accurate quantification of aerobic anoxygenic phototrophic bacteria (AAPB) is of crucial importance for estimation of the role of AAPB in the carbon cycling in marine ecosystems. The normally used method "epifiuorescence microscope-infrared photography (EFM-IRP)"is, however, subject to positive errors introduced by mistaking cyanobacteria as AAPB due to the visibility of cyanobacteria under infrared photographic conditions for AAPB. This error could be up to 30% in the coast of the East China Sea. Such bias should be avoided by either subtracting cyanobacteira from the total infrared counts or using a fiowcytometer equipped with specific detectors for discrimination between cyanobacteria and AAPB.

  11. Vertical distribution and characterization of aerobic phototrophic bacteria at the Juan de Fuca Ridge in the Pacific Ocean. (United States)

    Rathgeber, Christopher; Lince, Michael T; Alric, Jean; Lang, Andrew S; Humphrey, Elaine; Blankenship, Robert E; Verméglio, André; Plumley, F Gerald; Van Dover, Cindy L; Beatty, J Thomas; Yurkov, Vladimir


    The vertical distribution of culturable anoxygenic phototrophic bacteria was investigated at five sites at or near the Juan de Fuca Ridge in the Pacific Ocean. Twelve similar strains of obligately aerobic phototrophic bacteria were isolated in pure culture, from depths ranging from 500 to 2,379 m below the surface. These strains appear morphologically, physiologically, biochemically, and phylogenetically similar to Citromicrobium bathyomarinum strain JF-1, a bacterium previously isolated from hydrothermal vent plume waters. Only one aerobic phototrophic strain was isolated from surface waters. This strain is morphologically and physiologically distinct from the strains isolated at deeper sampling locations, and phylogenetic analysis indicates that it is most closely related to the genus Erythrobacter. Phototrophs were cultivated from three water casts taken above vents but not from two casts taken away from active vent sites. No culturable anaerobic anoxygenic phototrophs were detected. The photosynthetic apparatus was investigated in strain JF-1 and contains light-harvesting I and reaction center complexes, which are functional under aerobic conditions.


    NARCIS (Netherlands)



    The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for th

  13. Taxonomy of phototrophic green and purple bacteria: a review. (United States)

    Pfennig, N; Trüper, H G


    The presently existing classification for the green and purple bacteria comprises physiological-ecological assemblages of phototrophic bacteria with anoxygenic photosynthesis. The taxonomic units of the different levels were based entirely on common phenotypic traits, including morphological, cytological, physiological and biochemical characteristics. Since degrees of resemblance form the basis of the grouping, this classification cannot reflect the genetic or evolutionary relatedness of these bacteria, neither among themselves nor with other bacteria. The advantage of the artificial system, however, is the use of features which can be established in most laboratories and which allow the comparison and identification of newly isolated strains with those already studied and described. The four existing families correspond to the four major recognized, ecophysiological groups, the Chlorobiaceae and Chloroflexaceae among the green bacteria, and the Chromatiaceae and Rhodospirillaceae among the purple bacteria. Our knowledge of all these groups is incomplete; this is reflected by the fact that seven new species have been described during the past three years (6th Newsletter on phot. bacteria, Trüper and Hansen, 1982). The description of the new genus and species Erythrobacter longus (Shiba and Simidu, 1982) is also interesting, as it comprises aerobic chemoorganotrophic marine bacteria which form bacteriochlorophyll a and carotenoids; however, no strains were able to grow phototrophilcally. Significant success is currently being obtained in the different approaches toward elucidating the genetic relationships within and outside of the purple and green bacteria. Detailed studies of the lipopolysaccharides of several species and genera of the Rhodospirillaceae (Weckesser et al., 1979, and more recent paper) have proven to be very useful for the recognition of relationships or dissimilarities between the species of a genus or between different genera. Amino acid sequence

  14. Metagenomic evidence for the presence of phototrophic Gemmatimonadetes bacteria in diverse environments

    DEFF Research Database (Denmark)

    Zeng, Yonghui; Baumbach, Jan; Barbosa, Eudes Guilherme Vieira


    , biofilms, plant surfaces, intertidal sediment, soils, springs, and wastewater treatment plants, but none from marine waters or sediment. Phototrophic Gemmatimonadetes bacteria make up 0.4∼11.9% of whole phototrophic microbial communities in these habitats. Unexpectedly, an almost complete 37.9 kb long...... photosynthesis gene cluster (PGC) with identical gene composition and arrangement to those in G. phototrophica was reconstructed from the Odense wastewater metagenome, only differing in a 7.2 kb long non-photosynthesis-gene insert. These data suggest that phototrophic Gemmatimonadetes bacteria are much more...

  15. Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus. (United States)

    Gaisin, Vasil A; Grouzdev, Denis S; Namsaraev, Zorigto B; Sukhacheva, Marina V; Gorlenko, Vladimir M; Kuznetsov, Boris B


    Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range.

  16. Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia). (United States)

    Gaisin, Vasil A; Kalashnikov, Alexander M; Sukhacheva, Marina V; Namsaraev, Zorigto B; Barhutova, Darima D; Gorlenko, Vladimir M; Kuznetsov, Boris B


    Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus-like bacteria was detected in the Baikal rift zone.

  17. Oxygen and sulfur isotope fractionation during sulfide oxidation by anoxygenic phototrophic bacteria (United States)

    Brabec, Michelle Y.; Lyons, Timothy W.; Mandernack, Kevin W.


    Sulfide-mediated anoxygenic photosynthesis (SMAP) carried out by anaerobic phototrophic bacteria may have played an important role in sulfur cycling, formation of sulfate, and, perhaps, primary production in the Earth’s early oceans. Determination of ε34SSO4-Sulfide- and ε18OSO4-H2O values for bacterial sulfide oxidation will permit more refined interpretation of the δ34S and δ18OSO4 values measured in modern anoxic environments, such as meromictic lakes where sulfide commonly extends into the photic zone, and in the ancient rock record, particularly during periods of the Precambrian when anoxic and sulfidic (euxinic) conditions were believed to be more pervasive than today. Laboratory experiments with anaerobic purple and green sulfur phototrophs, Allochromatium vinosum and Chlorobaculum tepidum, respectively, were conducted to determine the sulfur and oxygen isotope fractionation during the oxidation of sulfide to sulfate. Replicate experiments were conducted at 25 °C for A. vinosum and 45 °C for C. tepidum, and in duplicate at three different starting oxygen isotope values for water to determine sulfate-water oxygen isotope fractionations accurately (ε18OSO4-H2O). ε18OSO4-H2O values of 5.6 ± 0.2‰ and 5.4 ± 0.1‰ were obtained for A. vinosum and C. tepidum, respectively. Temperature had no apparent effect on the ε18OSO4-H2O values. By combining all data from both cultures, an average ε18OSO4-H2O value of 5.6 ± 0.3‰ was obtained for SMAP. This value falls between those previously reported for bacterial oxidation of sphalerite and elemental sulfur (7-9‰) and abiotic and biotic oxidation of pyrite and chalcopyrite (2-4‰). Sulfur isotope fractionation between sulfide and sulfate formed by A.vinosum was negligible (0.1 ± 0.2‰) during all experiments. For C. tepidum an apparent fractionation of -2.3 ± 0.5‰ was observed during the earlier stages of oxidation based on bulk δ34S measurements of sulfate and sulfide and became smaller (-0.7

  18. Ciliates as engineers of phototrophic biofilms

    NARCIS (Netherlands)

    Weerman, Ellen J.; van der Geest, Harm G.; van der Meulen, Myra D.; Manders, Erik M. M.; van de Koppel, Johan; Herman, Peter M. J.; Admiraal, Wim


    1. Phototrophic biofilms consist of a matrix of phototrophs, non-photosynthetic bacteria and extracellular polymeric substances (EPS) which is spatially structured. Despite widespread exploitation of algae and bacteria within phototrophic biofilms, for example by protozoans, the 'engineering' effect

  19. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised (United States)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.


    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  20. Biofilm comprising phototrophic, diazotrophic, and hydrocarbon-utilizing bacteria: a promising consortium in the bioremediation of aquatic hydrocarbon pollutants. (United States)

    Al-Bader, Dhia; Kansour, Mayada K; Rayan, Rehab; Radwan, Samir S


    Biofilms harboring simultaneously anoxygenic and oxygenic phototrophic bacteria, diazotrophic bacteria, and hydrocarbon-utilizing bacteria were established on glass slides suspended in pristine and oily seawater. Via denaturing gradient gel electrophoresis analysis on PCR-amplified rRNA gene sequence fragments from the extracted DNA from biofilms, followed by band amplification, biofilm composition was determined. The biofilms contained anoxygenic phototrophs belonging to alphaproteobacteria; pico- and filamentous cyanobacteria (oxygenic phototrophs); two species of the diazotroph Azospirillum; and two hydrocarbon-utilizing gammaproteobacterial genera, Cycloclasticus and Oleibacter. The coexistence of all these microbial taxa with different physiologies in the biofilm makes the whole community nutritionally self-sufficient and adequately aerated, a condition quite suitable for the microbial biodegradation of aquatic pollutant hydrocarbons.

  1. Carbon metabolic pathways in phototrophic bacteria and their broader evolutionary implications

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiang eTang


    Full Text Available Photosynthesis is the biological process that converts solar energy to biomass, bio-products and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. Researchers have employed physiological studies, microbiological chemistry, enzyme assays, genome sequencing, transcriptomics, and 13C-based metabolomics/fluxomics to investigate central carbon metabolism and enzymes that operate in phototrophs. In this report, we review diverse CO2 assimilation pathways, acetate assimilation, carbohydrate catabolism, the TCA cycle and some key and/or unconventional enzymes in central carbon metabolism of phototrophic microorganisms. We also discuss the reducing equivalent flow during photoautotrophic and photoheterotrophic growth, evolutionary links in the central carbon metabolic network, and correlations between photosynthetic and non-photosynthetic organisms. Considering the metabolic versatility in these fascinating and diverse photosynthetic bacteria, many essential questions in their central carbon metabolism still remain to be addressed.

  2. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A


    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... and carotenoid species also allow the functions of these pigments to be studied in vivo....

  3. Simple and convenient method for culturing anaerobic bacteria.


    Behbehani, M J; Jordan, H. V.; Santoro, D L


    A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

  4. Anaerobic bacteria, the colon and colitis. (United States)

    Roediger, W E


    Anaerobic bacteria constitute more than 90% of the bacteria in the colon. An anaerobic environment is needed to maintain their growth and the production of short-chain fatty acids by these bacteria from carbohydrates. Short-chain fatty acids are rapidly absorbed and essential for metabolic as well as functional welfare of the colonic mucosa. The importance of these acids in water absorption and in the patogenesis of colitis is discussed in relation to the concept of "energy deficiency diseases" of the colonic mucosa.

  5. Abundance and genetic diversity of aerobic anoxygenic phototrophic bacteria of coastal regions of the pacific ocean. (United States)

    Ritchie, Anna E; Johnson, Zackary I


    Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic microbes that are found in a broad range of aquatic environments. Although potentially significant to the microbial ecology and biogeochemistry of marine ecosystems, their abundance and genetic diversity and the environmental variables that regulate these properties are poorly understood. Using samples along nearshore/offshore transects from five disparate islands in the Pacific Ocean (Oahu, Molokai, Futuna, Aniwa, and Lord Howe) and off California, we show that AAP bacteria, as quantified by the pufM gene biomarker, are most abundant near shore and in areas with high chlorophyll or Synechococcus abundance. These AAP bacterial populations are genetically diverse, with most members belonging to the alpha- or gammaproteobacterial groups and with subclades that are associated with specific environmental variables. The genetic diversity of AAP bacteria is structured along the nearshore/offshore transects in relation to environmental variables, and uncultured pufM gene libraries suggest that nearshore communities are distinct from those offshore. AAP bacterial communities are also genetically distinct between islands, such that the stations that are most distantly separated are the most genetically distinct. Together, these results demonstrate that environmental variables regulate both the abundance and diversity of AAP bacteria but that endemism may also be a contributing factor in structuring these communities.

  6. Genomic Insights into the Sulfur Metabolism of Phototrophic Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A.


    Green sulfur bacteria (GSB) utilize various combinations of sulfide, elemental sulfur, thiosulfate, ferrous iron, and hydrogen for anaerobic photoautotrophic growth. Genome sequence data is currently available for 12 strains of GSB. We present here a genome-based survey of the distribution...... strains, it appears that different enzymes may produce the same sulfur oxidation phenotype in different strains. Finally, even though the GSB are closely related, sequence analyses show that the sulfur metabolism gene content in these bacteria is substantially influenced by gene duplication...

  7. A new environment for aerobic anoxygenic phototrophic bacteria: biological soil crusts. (United States)

    Csotonyi, Julius T; Swiderski, Jolantha; Stackebrandt, Erko; Yurkov, Vladimir


    Phototrophic microorganisms are critical to the carbon cycling and productivity of biological soil crusts, which enhance water content, nutrient relations and mechanical stability of arid soils. Only oxygen-producing phototrophs, including cyanobacteria and algae, are known from soil crusts, but Earth's second major branch of photosynthetic organisms, the evolutionarily earlier anoxygenic phototrophs, is unreported. We announce the discovery of aerobic anoxygenic phototrophs in three Canadian soil crust communities. We found in a culture-based study that they comprised 0.1-5.9% of the cultivable bacterial community in moss-, lichen- and cyanobacteria-dominated crust from sand dunes and sandy soils. Comparable in density to aerobic phototrophs in other habitats, the bacteriochlorophyll a-possessing pink and orange isolates were related to species of Methylobacterium (99.0-99.5%), Belnapia (97.4-98.8%), Muricoccus (94.4%) and Sphingomonas (96.6-98.5%), based on 16S rRNA gene sequences. Our results demonstrate that proteobacterial anoxygenic phototrophs may be found in dry soil environments, implying desiccation resistance as yet unreported for this group. By utilizing sunlight for part of their energy needs, aerobic phototrophs can accelerate organic carbon cycling in nutrient-poor arid soils. Their effects will be especially important as global climate change enhances soil erosion and consequent nutrient loss.

  8. Photosynthetic characteristics of marine aerobic anoxygenic phototrophic bacteria Roseobacter and Erythrobacter strains. (United States)

    Sato-Takabe, Yuki; Hamasaki, Koji; Suzuki, Koji


    A coastal Roseobacter strain of marine aerobic anoxygenic phototrophic bacteria (AAnPB) was isolated and phylogenetically determined. The strain OBYS 0001 was characterized by its physiological and biochemical properties with reference to the Erythrobacter longus type strain NBRC 14126. When grown in batch cultures, the growth curves of the both strains were similar. Cellular bacteriochlorophyll a concentrations of the strains reached the maxima in the stationary growth conditions. In vivo fluorescence excitation/optical density spectra between 470 and 600 nm for OBYS 0001 represented higher values than NBRC 14126. Variable fluorescence measurements revealed that the functional absorption cross section (σ) of the bacterial photosynthetic complexes for OBYS 0001 was significantly higher than that for NBRC 14126 under green excitation. These results suggest that Roseobacter can capture green light more efficiently than Erythrobacter for photosynthesis. The photochemical quantum efficiencies (F (v)/F (m)) of the bacterial photosynthetic complexes for OBYS 0001 were consistently lower than those for NBRC 14126. A relationship between the growth rate and F (v)/F (m) was significant for OBYS 0001, but that was not found for NBRC 14126. These results suggested that F (v)/F (m) for AAnPB could not be used as a proxy of the growth rate which is consistent with their mostly heterotrophic characters.

  9. Antimicrobial resistance and susceptibility testing of anaerobic bacteria. (United States)

    Schuetz, Audrey N


    Infections due to anaerobic bacteria can be severe and life-threatening. Susceptibility testing of anaerobes is not frequently performed in laboratories, but such testing is important to direct appropriate therapy. Anaerobic resistance is increasing globally, and resistance trends vary by geographic region. An overview of a variety of susceptibility testing methods for anaerobes is provided, and the advantages and disadvantages of each method are reviewed. Specific clinical situations warranting anaerobic susceptibility testing are discussed.

  10. Ciliates as engineers of phototrophic biofilms.

    NARCIS (Netherlands)

    Weerman, E.J.; Geest, H.G.; Meulen, M.D.; Manders, E.M.M.; Van de Koppel, J.; Herman, P.M.J.; Admiraal, W.


    1.Phototrophic biofilms consist of a matrix of phototrophs, non-photosynthetic bacteria and extracellular polymeric substances (EPS) which is spatially structured. Despite widespread exploitation of algae and bacteria within phototrophic biofilms, for example by protozoans, the ‘engineering’ effects

  11. Ciliates as engineers of phototrophic biofilms.

    NARCIS (Netherlands)

    Weerman, E.J.; van der Geest, H.G.; van der Meulen, M.D; Manders, E.M.M.; van de Koppel, J.; Herman, P.M.J.; Admiraal, W.


    1. Phototrophic biofilms consist of a matrix of phototrophs, non-photosynthetic bacteria and extracellular polymeric substances (EPS) which is spatially structured. Despite widespread exploitation of algae and bacteria within phototrophic biofilms, for example by protozoans, the ‘engineering’ effect

  12. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter


    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...... consortia. Despite the potentially adverse effects, only few inorganic electron acceptors potentially utilizable for anaerobic respiration have been investigated with respect to negative interactions in anaerobic digesters. In this chapter we review competitive and inhibitory interactions between anaerobic...... respiring populations and methanogenic consortia in bioreactors. Due to the few studies in anaerobic digesters, many of our discussions are based upon studies of defined cultures or natural ecosystems...

  13. [Antimicrobial susceptibility testing of anaerobic bacteria]. (United States)

    García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada


    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.

  14. CO2 assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria

    DEFF Research Database (Denmark)

    Storelli, Nicola; Peduzzi, Sandro; Saad, Maged;


    Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix CO₂. The purple sulfu...

  15. Singlet-triplet fission of carotenoid excitation in light-harvesting LH2 complexes of purple phototrophic bacteria. (United States)

    Klenina, I B; Makhneva, Z K; Moskalenko, A A; Gudkov, N D; Bolshakov, M A; Pavlova, E A; Proskuryakov, I I


    The current generally accepted structure of light-harvesting LH2 complexes from purple phototrophic bacteria conflicts with the observation of singlet-triplet carotenoid excitation fission in these complexes. In LH2 complexes from the purple bacterium Allochromatium minutissimum, a drop in the efficiency of carotenoid triplet generation is demonstrated, which correlates with the extent of selective photooxidation of bacteriochlorophylls absorbing at ~850 nm. We conclude that singlet-triplet fission of carotenoid excitation proceeds with participation of these excitonically coupled bacteriochlorophylls. In the framework of the proposed mechanism, the contradiction between LH2 structure and photophysical properties of carotenoids is eliminated. The possibility of singlet-triplet excitation fission involving a third mediator molecule was not considered earlier.

  16. Comparison of growth rates of aerobic anoxygenic phototrophic bacteria and other bacterioplankton groups in coastal Mediterranean waters. (United States)

    Ferrera, Isabel; Gasol, Josep M; Sebastián, Marta; Hojerová, Eva; Koblízek, Michal


    Growth is one of the basic attributes of any living organism. Surprisingly, the growth rates of marine bacterioplankton are only poorly known. Current data suggest that marine bacteria grow relatively slowly, having generation times of several days. However, some bacterial groups, such as the aerobic anoxygenic phototrophic (AAP) bacteria, have been shown to grow much faster. Two manipulation experiments, in which grazing, viruses, and resource competition were reduced, were conducted in the coastal Mediterranean Sea (Blanes Bay Microbial Observatory). The growth rates of AAP bacteria and of several important phylogenetic groups (the Bacteroidetes, the alphaproteobacterial groups Roseobacter and SAR11, and the Gammaproteobacteria group and its subgroups the Alteromonadaceae and the NOR5/OM60 clade) were calculated from changes in cell numbers in the manipulation treatments. In addition, we examined the role that top-down (mortality due to grazers and viruses) and bottom-up (resource availability) factors play in determining the growth rates of these groups. Manipulations resulted in an increase of the growth rates of all groups studied, but its extent differed largely among the individual treatments and among the different groups. Interestingly, higher growth rates were found for the AAP bacteria (up to 3.71 day⁻¹) and for the Alteromonadaceae (up to 5.44 day⁻¹), in spite of the fact that these bacterial groups represented only a very low percentage of the total prokaryotic community. In contrast, the SAR11 clade, which was the most abundant group, was the slower grower in all treatments. Our results show that, in general, the least abundant groups exhibited the highest rates, whereas the most abundant groups were those growing more slowly, indicating that some minor groups, such the AAP bacteria, very likely contribute much more to the recycling of organic matter in the ocean than what their abundances alone would predict.

  17. Methane and hydrogen production by human intestinal anaerobic bacteria. (United States)

    McKay, L F; Holbrook, W P; Eastwood, M A


    The gas above liquid cultures of a variety of human intestinal anaerobic bacteria was sampled and analysed by headspace gas chromatography. Hydrogen production was greatest with strains of the genus Clostridium, intermediate with anaerobic cocci and least with Bacteroides sp. Very few strains produced methane although small amounts were detected with one strain of B. thetaiotaomicron, C. perfringens and C. histolyticum. There may be a relationship between these anaerobic bacteria and several gastrointestinal disorders in which there is a build up of hydrogen or methane in the intestines.

  18. Diversity and Distribution of Freshwater Aerobic Anoxygenic Phototrophic Bacteria across a Wide Latitudinal Gradient (United States)

    Ferrera, Isabel; Sarmento, Hugo; Priscu, John C.; Chiuchiolo, Amy; González, José M.; Grossart, Hans-Peter


    Aerobic anoxygenic phototrophs (AAPs) have been shown to exist in numerous marine and brackish environments where they are hypothesized to play important ecological roles. Despite their potential significance, the study of freshwater AAPs is in its infancy and limited to local investigations. Here, we explore the occurrence, diversity and distribution of AAPs in lakes covering a wide latitudinal gradient: Mongolian and German lakes located in temperate regions of Eurasia, tropical Great East African lakes, and polar permanently ice-covered Antarctic lakes. Our results show a widespread distribution of AAPs in lakes with contrasting environmental conditions and confirm that this group is composed of different members of the Alpha- and Betaproteobacteria. While latitude does not seem to strongly influence AAP abundance, clear patterns of community structure and composition along geographic regions were observed as indicated by a strong macro-geographical signal in the taxonomical composition of AAPs. Overall, our results suggest that the distribution patterns of freshwater AAPs are likely driven by a combination of small-scale environmental conditions (specific of each lake and region) and large-scale geographic factors (climatic regions across a latitudinal gradient). PMID:28275369

  19. The identification of anaerobic bacteria using MALDI-TOF MS

    NARCIS (Netherlands)

    Veloo, A. C. M.; Welling, G. W.; Degener, J. E.


    Matrix Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has gained more and more popularity for the identification of bacteria. Several studies show that bacterial diagnosticis is being revolutionized by the application of MALDI-TOF MS. For anaerobic bacteria,

  20. CO₂ assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria. (United States)

    Storelli, Nicola; Peduzzi, Sandro; Saad, Maged M; Frigaard, Niels-Ulrik; Perret, Xavier; Tonolla, Mauro


    Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix CO₂. The purple sulfur bacterium Candidatus 'Thiodictyon syntrophicum' strain Cad16(T) had the highest CO₂ assimilation rate in the light of the four strains tested and had a high CO₂ assimilation rate even in the dark. The CO₂ assimilation of the population represented by strain Cad16(T) was estimated to be up to 25% of the total primary production in the chemocline. Pure cultures of strain Cad16(T) exposed to cycles of 12 h of light and 12 h of darkness exhibited the highest CO₂ assimilation during the first 4 h of light. The draft genome sequence of Cad16(T) showed the presence of cbbL and cbbM genes, which encode form I and form II of RuBisCO, respectively. Transcription analyses confirmed that, whereas cbbM remained poorly expressed throughout light and dark exposure, cbbL expression varied during the light-dark cycle and was affected by the available carbon sources. Interestingly, the peaks in cbbL expression did not correlate with the peaks in CO₂ assimilation.

  1. Biochemistry and physiology of anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)



    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.

  2. Sulfate-reducing bacteria in anaerobic bioreactors.

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.


    The treatment of industrial wastewaters containing high amounts of easily degradable organic compounds in anaerobic bioreactors is a well-established process. Similarly, wastewaters which in addition to organic compounds also contain sulfate can be treated in this way. For a long time, the occurrenc

  3. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    C. Jeanthon


    Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a, the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 % was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies

  4. Malate dehydrogenase in phototrophic purple bacteria: purification, molecular weight, and quaternary structure.



    The citric acid cycle enzyme malate dehydrogenase was purified to homogeneity from the nonsulfur purple bacteria Rhodobacter capsulatus, Rhodospirillum rubrum, Rhodomicrobium vannielii, and Rhodocyclus purpureus. Malate dehydrogenase was purified from each species by either a single- or a two-step protocol: triazine dye affinity chromatography was the key step in purification of malate dehydrogenase in all cases. Purification of malate dehydrogenase resulted in a 130- to 240-fold increase in ...

  5. Anaerobic degradation of benzoate by sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Silva, S.P.; Adorno, M.A.T.; Moraes, E.M.; Varesche, M.B.A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Biological Processes Laboratory


    Anaerobic processes are an efficient way to degrade aromatic compounds in industrial wastewater, such as phenol, cresol and benzoate. This study characterized the bacteria that degrades benzoate, an anaerobic degradation intermediate of several complex aromatic compounds. In particular, the study assessed the capacity to use benzoate with sulfate reducing bacteria in mesophilic conditions. Biofilm from polyurethane foam matrices of a fixed bed reactor was used as the cellular inoculum to treat industrial wastewater containing organic peroxide. Dilution techniques were used to purify the material and obtain cultures of cocci. The benzoate consumption capacity in sulfidogenic conditions was observed when the purified inoculum was applied to batch reactors with different benzoate/sulfate relations. Results indicate that purification was positive to bacteria that can degrade aromatic compounds. Desulfococcus multivorans bacteria was identified following the physiologic and kinetic experiments. The 0.6 benzoate/sulfate relation was considered ideal for complete consumption of carbon and total use of sulfur. 10 refs., 3 figs.

  6. A single-cell view on the ecophysiology of anaerobic phototrophic bacteria

    DEFF Research Database (Denmark)

    Musat, Niculina; Halm, Hannah; Winterholler, Bärbel


    the oligotrophic, meromictic Lake Cadagno were analyzed with respect to H13CO3- and 15NH4+ assimilation. Metabolic rates were found to vary greatly between individual cells of the same species, showing that microbial populations in the environment are heterogeneous, being comprised of physiologically distinct...... in the nitrogen and carbon cycles in the environment. By introducing this quantification method for the ecophysiological roles of individual cells, our study opens a variety of possibilities of research in environmental microbiology, especially by increasing the ability to examine the ecophysiological roles......Quantitative information on the ecophysiology of individual microorganisms is generally limited because it is difficult to assign specific metabolic activities to identified single cells. Here, we develop and apply a method, Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH...

  7. Cultivation of anaerobic and facultatively anaerobic bacteria from spacecraft-associated clean rooms. (United States)

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


    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.

  8. A simple and sensitive quality control method of the anaerobic atmosphere for identification and antimicrobial susceptibility testing of anaerobic bacteria

    DEFF Research Database (Denmark)

    Justesen, Tage; Justesen, Ulrik Stenz


    The maintenance of a strict anaerobic atmosphere is essential for the culture of strict anaerobic bacteria. We describe a simple and sensitive quality control method of the anaerobic atmosphere, based on the measurement of the zone diameter around a 5-μg metronidazole disk when testing an aerotol...

  9. Impact of a simulated oil spill on benthic phototrophs and nitrogen-fixing bacteria in mudflat mesocosms

    NARCIS (Netherlands)

    Chronopoulou, P.-M.; Fahy, A.; Coulon, F.; Païssé, S.; Goñi-Urriza, M.; Peperzak, L.; Acuña Alvarez, L.; McKew, B.A.; Lawson, T.; Timmis, K.N.; Duran, R.; Underwood, G.J.C.; McGenity, T.J.


    Coastal and estuarine ecosystems are highly susceptible to crude oil pollution. Therefore, in order to examine the resilience of benthic phototrophs that are pivotal to coastal ecosystem functioning, we simulated an oil spill in tidal mesocosms consisting of intact sediment cores from a mudflat at t

  10. Cellulose fermentation by nitrogen-fixing anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Canale-Parola, E.


    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. [Anaerobic bacteria 150 years after their discovery by Pasteur]. (United States)

    García-Sánchez, José Elías; García-Sánchez, Enrique; Martín-Del-Rey, Ángel; García-Merino, Enrique


    In 2011 we celebrated the 150th anniversary of the discovery of anaerobic bacteria by Louis Pasteur. The interest of the biomedical community on such bacteria is still maintained, and is particularly focused on Clostridium difficile. In the past few years important advances in taxonomy have been made due to the genetic, technological and computing developments. Thus, a significant number of new species related to human infections have been characterised, and some already known have been reclassified. At pathogenic level some specimens of anaerobic microflora, that had not been isolated from human infections, have been now isolated in some clinical conditions. There was emergence (or re-emergence) of some species and clinical conditions. Certain anaerobic bacteria have been associated with established infectious syndromes. The virulence of certain strains has increased, and some hypotheses on their participation in certain diseases have been given. In terms of diagnosis, the routine use of MALDI-TOF has led to a shortening of time and a cost reduction in the identification, with an improvement directly related to the improvement of data bases. The application of real-time PCR has been another major progress, and the sequencing of 16srRNA gene and others is currently a reality for several laboratories. Anaerobes have increased their resistance to antimicrobial agents, and the emergence of resistance to carbapenems and metronidazole, and multi-resistance is a current reality. In this situation, linezolid could be an effective alternative for Bacteroides. Fidaxomicin is the only anti-anaerobic agent introduced in the recent years, specifically for the diarrhoea caused by C.difficile. Moreover, some mathematical models have also been proposed in relation with this species.

  12. Anaerobic bacteria in the intestinal microbiota of Brazilian children (United States)

    Talarico, Silvia T; Santos, Florenza E; Brandt, Katia Galeão; Martinez, Marina B; Taddei, Carla R


    OBJECTIVE: Changes in the neonatal gut environment allow for the colonization of the mucin layer and lumen by anaerobic bacteria. The aim of the present study was to evaluate Bifidobacterium, Lactobacillus and Lactococcus colonization through the first year of life in a group of 12 Brazilian infants and to correlate these data with the levels of Escherichia coli. The presence of anaerobic members of the adult intestinal microbiota, including Eubacterium limosum and Faecalibacterium prausnitzii, was also evaluated. METHODS: Fecal samples were collected during the first year of life, and 16S rRNA from anaerobic and facultative bacteria was detected by real-time PCR. RESULTS: Bifidobacterium was present at the highest levels at all of the studied time points, followed by E. coli and Lactobacillus. E. limosum was rarely detected, and F. prausnitzii was detected only in the samples from the latest time points. CONCLUSION: These results are consistent with reports throughout the world on the community structure of the intestinal microbiota in infants fed a milk diet. Our findings also provide evidence for the influence of the environment on intestinal colonization due to the high abundance of E. coli. The presence of important anaerobic genera was observed in Brazilian infants living at a low socioeconomic level, a result that has already been well established for infants living in developed countries.

  13. Enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jie


    The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor. Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1. In this study, The nitrogen removal efficiency was up to 80% and the molar-reaction ratio of ammonium, nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.

  14. Oxidation and methylation of dissolved elemental mercury by anaerobic bacteria (United States)

    Hu, Haiyan; Lin, Hui; Zheng, Wang; Tomanicek, Stephen J.; Johs, Alexander; Feng, Xinbin; Elias, Dwayne A.; Liang, Liyuan; Gu, Baohua


    Methylmercury is a neurotoxin that poses significant health risks to humans. Some anaerobic sulphate- and iron-reducing bacteria can methylate oxidized forms of mercury, generating methylmercury. One strain of sulphate-reducing bacteria (Desulfovibrio desulphuricans ND132) can also methylate elemental mercury. The prevalence of this trait among different bacterial strains and species remains unclear, however. Here, we compare the ability of two strains of the sulphate-reducing bacterium Desulfovibrio and one strain of the iron-reducing bacterium Geobacter to oxidize and methylate elemental mercury in a series of laboratory incubations. Experiments were carried out under dark, anaerobic conditions, in the presence of environmentally relevant concentrations of elemental mercury. We report differences in the ability of these organisms to oxidize and methylate elemental mercury. In line with recent findings, we show that D.desulphuricans ND132 can both oxidize and methylate elemental mercury. We find that the rate of methylation of elemental mercury is about one-third the rate of methylation of oxidized mercury. We also show that Desulfovibrio alaskensis G20 can oxidize, but not methylate, elemental mercury. Geobacter sulphurreducens PCA is able to oxidize and methylate elemental mercury in the presence of cysteine. We suggest that the activity of methylating and non-methylating bacteria may together enhance the formation of methylmercury in anaerobic environments.

  15. Effect of anaerobic bovine colostrum fermentation on bacteria growth inhibition

    Directory of Open Access Journals (Sweden)

    Mara Helena Saalfeld

    Full Text Available ABSTRACT: Efficient handling programs that provide high quality colostrum in adequate amounts to dairy farm calves are needed to assure their health and survival. Replacers (or milk substitutes often become necessary when colostrum presents inadequate quality, or in order to break the cycle of infectious disease transmission. In this study we aimed to assess the effect of anaerobic fermentation processing (colostrum silage on bacterial that represent interest to animal health. Colostrum samples were inoculated with cultures of Brucella abortus , Escherichia coli , Leptospira interrogans serovar Copenhageni , Mycobacterium bovis , Salmonella Enteritidis , Salmonella Typhimurium , Staphylococcus aureus , and Bacillus cereus and then subjected to anaerobic fermentation. On the first day, and every seven days until 30th days after fermentation, the samples were cultured and colony forming units counted. At seven days of fermentation, B. abortus , L. interrogans , and M. bovis were not detected. At 14th days of fermentation, E. coli , S. aureus , S. Enteritidis and S. Typhimurium were no longer detected. However, we were able to detect both lactic acid bacteria and B. cereus until 30th days of fermentation. From this study we suggested that anaerobic fermentation processing can inhibit important bacteria that cause economical losses for the cattle industry. The observations suggested that colostrum silage is a promising form to conserve bovine colostrum.

  16. Oxygen regulated gene expression in facultatively anaerobic bacteria. (United States)

    Unden, G; Becker, S; Bongaerts, J; Schirawski, J; Six, S


    In facultatively anaerobic bacteria such as Escherichia coli, oxygen and other electron acceptors fundamentally influence catabolic and anabolic pathways. E. coli is able to grow aerobically by respiration and in the absence of O2 by anaerobic respiration with nitrate, nitrite, fumarate, dimethylsulfoxide and trimethylamine N-oxide as acceptors or by fermentation. The expression of the various catabolic pathways occurs according to a hierarchy with 3 or 4 levels. Aerobic respiration at the highest level is followed by nitrate respiration (level 2), anaerobic respiration with the other acceptors (level 3) and fermentation. In other bacteria, different regulatory cascades with other underlying principles can be observed. Regulation of anabolism in response to O2 availability is important, too. It is caused by different requirements of cofactors or coenzymes in aerobic and anaerobic metabolism and by the requirement for different O2-independent biosynthetic routes under anoxia. The regulation mainly occurs at the transcriptional level. In E. coli, 4 global regulatory systems are known to be essential for the aerobic/anaerobic switch and the described hierarchy. A two-component sensor/regulator system comprising ArcB (sensor) and ArcA (transcriptional regulator) is responsible for regulation of aerobic metabolism. The FNR protein is a transcriptional sensor-regulator protein which regulates anaerobic respiratory genes in response to O2 availability. The gene activator FhlA regulates fermentative formate and hydrogen metabolism with formate as the inductor. ArcA/B and FNR directly respond to O2, FhlA indirectly by decreased levels of formate in the presence of O2. Regulation of nitrate/nitrite catabolism is effected by two 2-component sensor/regulator systems NarX(Q)/NarL(P) in response to nitrate/nitrite. Co-operation of the different regulatory systems at the target promoters which are in part under dual (or manifold) transcriptional control causes the expression

  17. Overcoming the hypoxic barrier to radiation therapy with anaerobic bacteria. (United States)

    Bettegowda, Chetan; Dang, Long H; Abrams, Ross; Huso, David L; Dillehay, Larry; Cheong, Ian; Agrawal, Nishant; Borzillary, Scott; McCaffery, J Michael; Watson, E Latice; Lin, Kuo-Shyan; Bunz, Fred; Baidoo, Kwamena; Pomper, Martin G; Kinzler, Kenneth W; Vogelstein, Bert; Zhou, Shibin


    The low level of oxygenation within tumors is a major cause of radiation treatment failures. We theorized that anaerobic bacteria that can selectively destroy the hypoxic regions of tumors would enhance the effects of radiation. To test this hypothesis, we used spores of Clostridium novyi-NT to treat transplanted tumors in mice. The bacteria were found to markedly improve the efficacy of radiotherapy in several of the mouse models tested. Enhancement was noted with external beam radiation derived from a Cs-137 source, systemic radioimmunotherapy with an I-131-conjugated monoclonal antibody, and a previously undescribed form of experimental brachytherapy using plaques loaded with I-125 seeds. C. novyi-NT spores added little toxicity to the radiotherapeutic regimens, and the combination resulted in long-term remissions in a significant fraction of animals.

  18. Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Miyahara, Michiko; Miyahara, Makoto [National Inst. of Health Sciences, Tokyo (Japan)


    An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D{sub 10}) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

  19. Biological hydrogen production by moderately thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    HP Goorissen; AJM Stams [Laboratory of Microbiology, Wageningen University and Research centre Wageningen (Netherlands)


    This study focuses on the biological production of hydrogen at moderate temperatures (65-75 C) by anaerobic bacteria. A survey was made to select the best (moderate) thermophiles for hydrogen production from cellulolytic biomass. From this survey we selected Caldicellulosiruptor saccharolyticus (a gram-positive bacterium) and Thermotoga elfii (a gram-negative bacterium) as potential candidates for biological hydrogen production on mixtures of C{sub 5}-C{sub 6} sugars. Xylose and glucose were used as model substrates to describe growth and hydrogen production from hydrolyzed biomass. Mixed substrate utilization in batch cultures revealed differences in the sequence of substrate consumption and in catabolites repression of the two microorganisms. The regulatory mechanisms of catabolites repression in these microorganisms are not known yet. (authors)

  20. Technique for preparation of anaerobic microbes: Rodshaped cellulolytic bacteria

    Directory of Open Access Journals (Sweden)

    Amlius Thalib


    Full Text Available Preparation of anaerobic-rod cellulolytic bacteria with coating technique has been conducted. Steps of the processes involved were cultivation, coating, evaporation, and drying. Coating agent used was Gum Arabic, and drying techniquesconducted were freeze drying and sun drying. pH of culture media was firstly optimized to obtain the maximal population ofbacteria. Both coated and uncoated preparates were subjected to drying. Morphological and Gram type identifications showed that uncoated preparate dried with freeze drying is not contaminated (ie. all bacteria are rod shape with Gram-negative type while the one dried with sun drying is not morphologically pure (ie. containing of both rod and coccus shapes with Gram negative and positive. The coated preparates dried by both freeze and sun drying, were not contaminated (ie. all are rods with Gram-negative. The coating and drying processes decreased viability of preparates significantly. However, the decreasing of viability of coated preparate are lower than uncoated preparate (ie. 89 vs. 97%. Total count of bacteria in sun-drying coated preparate are higher (P<0.05 than the uncoated preparate (ie. 3.38 x 1010 vs. 1.97 x 1010 colony/g DM. Activity of sun-drying coated preparate to digest elephant grass and rice straw was higher (P<0.01 than the sun-drying uncoated preparate with the in vitro DMD values were 42.7 vs. 35.5% for elephant grass substrate and 29.3 vs. 24.6% for rice straw substrate. Therefore, it is concluded that coating technique has a positive effects on the preparation of rumen bacteria.

  1. Impact of a simulated oil spill on benthic phototrophs and nitrogen-fixing bacteria in mudflat mesocosms. (United States)

    Chronopoulou, Panagiota-Myrsini; Fahy, Anne; Coulon, Frédéric; Païssé, Sandrine; Goñi-Urriza, Marisol; Peperzak, Louis; Acuña Alvarez, Laura; McKew, Boyd A; Lawson, Tracy; Timmis, Kenneth N; Duran, Robert; Underwood, Graham J C; McGenity, Terry J


    Coastal and estuarine ecosystems are highly susceptible to crude oil pollution. Therefore, in order to examine the resilience of benthic phototrophs that are pivotal to coastal ecosystem functioning, we simulated an oil spill in tidal mesocosms consisting of intact sediment cores from a mudflat at the mouth of the Colne Estuary, UK. At day 21, fluorescence imaging revealed a bloom of cyanobacteria on the surface of oiled sediment cores, and the upper 1.5 cm thick sediment had 7.2 times more cyanobacterial and 1.7 times more diatom rRNA sequences when treated with oil. Photosystem II operating efficiency (Fq'/Fm') was significantly reduced in oiled sediments at day 7, implying that the initial diatom-dominated community was negatively affected by oil, but this was no longer apparent by day 21. Oil addition significantly reduced numbers of the key deposit feeders, and the decreased grazing pressure is likely to be a major factor in the increased abundance of both diatoms and cyanobacteria. By day 5 concentrations of dissolved inorganic nitrogen were significantly lower in oiled mesocosms, likely resulting in the observed increase in nifH-containing, and therefore potentially dinitrogen-fixing, cyanobacteria. Thus, indirect effects of oil, rather than direct inhibition, are primarily responsible for altering the microphytobenthos.


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    Full Text Available One hundred six patients with clinical diagnosis of CSOM were investigated bacteriologically using appropriate aerobic and anaerobic techniques. Positive cultures were obtained in 100 specimens. Aerobic bacteria alone were present in 51%, anaerobic bacteria alone in 10% and a combination of both in 34% of aural swabs . The anaerobes isolated were Bacteroides 30%, Peptostreptococci 26%, followed by others. Aerobic bacteriology showed the predominance of Pseudomonas 30.4% followed by Staphylococcus aureus 21.4%. Metronidazole was found to be most effective (87% drug aga inst anaerobes and Amikacin (98% against aerobes.

  3. Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells. (United States)

    Wunsch, Christopher M; Lewis, Janina P


    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

  4. Anaerobic degradation of benzene by marine sulfate-reducing bacteria (United States)

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


    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

  5. Anaerobic bacteria in the gut of terrestrial isopod Crustacean Porcellio scaber. (United States)

    Kostanjsek, R; Lapanje, A; Rupnik, M; Strus, J; Drobne, D; Avgustin, G


    Anaerobic bacteria from Porcellio scaber hindgut were identified and, subsequently, isolated using molecular approach. Phylogenetic affiliation of bacteria associated with the hindgut wall was determined by analysis of bacterial 16S rRNA gene sequences which were retrieved directly from washed hindguts of P. scaber. Sequences from bacteria related to obligate anaerobic bacteria from genera Bacteroides and Enterococcus were retrieved, as well as sequences from 'A1 subcluster' of the wall-less mollicutes. Bacteria from the genus Desulfotomaculum were isolated from gut wall and cultivated under anaerobic conditions. In contrast to previous reports which suggested the absence of anaerobic bacteria in the isopod digestive system due to short retention time of the food in the tube-like hindgut, frequent renewal of the gut cuticle during the moulting process, and unsuccessful attempts to isolate anaerobic bacteria from this environment our results indicate the presence of resident anaerobic bacteria in the gut of P. scaber, in spite of apparently unsuitable, i.e. predominantly oxic, conditions.

  6. Regulation of multiple carbon monoxide consumption pathways in anaerobic bacteria

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    Stephen M Techtmann


    Full Text Available Carbon monoxide (CO, well known as a toxic gas, is increasingly recognized as a key metabolite and signaling molecule. Microbial utilization of CO is quite common, evidenced by the rapid escalation in description of new species of CO-utilizing bacteria and archaea. Carbon monoxide dehydrogenase (CODH, the protein complex that enables anaerobic CO utilization has been well-characterized from an increasing number of microorganisms, however the regulation of multiple CO-related gene clusters in single isolates remains unexplored. Many species are extroraordinarily resistant to high CO concentrations, thiriving under pure CO at more than one atmosphere. We hypothesized that, in strains that can grow exclusively on CO, both carbon acquisition via the CODH/Acetyl CoA synthase complex and energy conservation via a CODH-linked hydrogenase must be differentially regulated in response to the availability of CO. The CO-sensing transcriptional activator, CooA is present in most CO-oxidizing bacteria. Here we present a genomic and phylogenetic survey of CODH operons and cooA genes found in CooA-containing bacteria. Two distinct groups of CooA homologs were found: One clade (CooA-1 is found in the majority of CooA containing bacteria, whereas the other clade (CooA-2 is found only in genomes that encode multiple CODH clusters, suggesting that the CooA-2 might be important for cross-regulation of competing CODH operons. Recombinant CooA-1 and CooA-2 regulators from the prototypical CO-utilizing bacterium Carboxydothermus hydrogenoformans were purified, and promoter binding analyses revealed that CooA-1 specifically regulates the hydrogenase-linked CODH, whereas CooA-2 is able to regulate both the hydrogenase-linked CODH and the CODH/ACS operons. These studies point to the ability of dual CooA homologs to partition CO into divergent CO-utilizing pathways resulting in efficient consumption of a single limiting growth substrate available across a wide range of

  7. Nitrogen removal by autotrophic ammonium oxidizing bacteria enrichment under anaerobic conditions

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    Pongsak (Lek Noophan


    Full Text Available Sludge from an anoxic tank at the centralized wastewater treatment plant, Nong Khaem, Bangkok, Thailand, was inoculatedin an anaerobic sequencing batch reactor (ASBR. The optimal compositions and operating conditions of the stock of autotrophic ammonium oxidizing bacteria medium were determined. The process of oxidizing ammonium with bacteria under anaerobic conditions is often referred to as the Anammox process (NO2- to N2 gas, using NH4+ as the electron donor and NO2- as the electron acceptor. The startup period for the anammox culture took more than three months. With ammoniumand nitrite concentration ratios of 1:1.38 and 1:1.6, the nitrogen conversion rate zero order. Fluorescent in situ hybridization(FISH was used to identify specific autotrophic ammonium oxidizing bacteria (Nitrosomonas spp., Candidatus Brocadia anammoxidans, and Candidatus Kuenenia stuttgartiensis. Results from this work demonstrated a shift in the species of ammonium oxidizing bacteria from Nitrosomonas spp. to Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis, with increased ammonium concentrations from 3 mM to 15 mM. Under NH4+:NO2- ratios of 1:1.38 and 1:1.6 the ammoniumoxidizing bacteria were able to remove both ammonium and nitrite simultaneously. The specific nitrogen removal rate of theanammox bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis was significantly higher than that of anaerobic ammonium oxidizing bacteria (Nitrosomonas spp.. Anaerobic ammonium oxidizing bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis are strict anaerobes.

  8. Physiology and phylogeny of green sulfur bacteria forming a monospecific phototrophic assemblage at a depth of 100 meters in the Black Sea. (United States)

    Manske, Ann K; Glaeser, Jens; Kuypers, Marcel M M; Overmann, Jörg


    The biomass, phylogenetic composition, and photoautotrophic metabolism of green sulfur bacteria in the Black Sea was assessed in situ and in laboratory enrichments. In the center of the western basin, bacteriochlorophyll e (BChl e) was detected between depths of 90 and 120 m and reached maxima of 54 and 68 ng liter(-1). High-pressure liquid chromatography analysis revealed a dominance of farnesyl esters and the presence of four unusual geranyl ester homologs of BChl e. Only traces of BChl e (8 ng liter(-1)) were found at the northwestern slope of the Black Sea basin, where the chemocline was positioned at a significantly greater depth of 140 m. Stable carbon isotope fractionation values of farnesol indicated an autotrophic growth mode of the green sulfur bacteria. For the first time, light intensities in the Black Sea chemocline were determined employing an integrating quantum meter, which yielded maximum values between 0.0022 and 0.00075 micromol quanta m(-2) s(-1) at the top of the green sulfur bacterial layer around solar noon in December. These values represent by far the lowest values reported for any habitat of photosynthetic organisms. Only one 16S rRNA gene sequence type was detected in the chemocline using PCR primers specific for green sulfur bacteria. This previously unknown phylotype groups with the marine cluster of the Chlorobiaceae and was successfully enriched in a mineral medium containing sulfide, dithionite, and freshly prepared yeast extract. Under precisely controlled laboratory conditions, the enriched green sulfur bacterium proved to be capable of exploiting light intensities as low as 0.015 micromol quanta m(-2) s(-1) for photosynthetic 14CO2 fixation. Calculated in situ doubling times of the green sulfur bacterium range between 3.1 and 26 years depending on the season, and anoxygenic photosynthesis contributes only 0.002 to 0.01% to total sulfide oxidation in the chemocline. The stable population of green sulfur bacteria in the Black Sea

  9. Metabolism of Hydrocarbons in n-Alkane-Utilizing Anaerobic Bacteria. (United States)

    Wilkes, Heinz; Buckel, Wolfgang; Golding, Bernard T; Rabus, Ralf


    The glycyl radical enzyme-catalyzed addition of n-alkanes to fumarate creates a C-C-bond between two concomitantly formed stereogenic carbon centers. The configurations of the two diastereoisomers of the product resulting from n-hexane activation by the n-alkane-utilizing denitrifying bacterium strain HxN1, i.e. (1-methylpentyl)succinate, were assigned as (2S,1'R) and (2R,1'R). Experiments with stereospecifically deuterated n-(2,5-2H2)hexanes revealed that exclusively the pro-S hydrogen atom is abstracted from C2 of the n-alkane by the enzyme and later transferred back to C3 of the alkylsuccinate formed. These results indicate that the alkylsuccinate-forming reaction proceeds with an inversion of configuration at the carbon atom (C2) of the n-alkane forming the new C-C-bond, and thus stereochemically resembles a SN2-type reaction. Therefore, the reaction may occur in a concerted manner, which may avoid the highly energetic hex-2-yl radical as an intermediate. The reaction is associated with a significant primary kinetic isotope effect (kH/kD ≥3) for hydrogen, indicating that the homolytic C-H-bond cleavage is involved in the first irreversible step of the reaction mechanism. The (1-methylalkyl)succinate synthases of n-alkane-utilizing anaerobic bacteria apparently have very broad substrate ranges enabling them to activate not only aliphatic but also alkyl-aromatic hydrocarbons. Thus, two denitrifiers and one sulfate reducer were shown to convert the nongrowth substrate toluene to benzylsuccinate and further to the dead-end product benzoyl-CoA. For this purpose, however, the modified β-oxidation pathway known from alkylbenzene-utilizing bacteria was not employed, but rather the pathway used for n-alkane degradation involving CoA ligation, carbon skeleton rearrangement and decarboxylation. Furthermore, various n-alkane- and alkylbenzene-utilizing denitrifiers and sulfate reducers were found to be capable of forming benzyl alcohols from diverse alkylbenzenes


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    We describe a flow cytometry method for analysis of noncultured anaerobic bacteria present in human fecal suspensions. Nonbacterial fecal compounds, bacterial fragments, and large aggregates could be discriminated from bacteria by staining with propidium iodide (PI) and setting a discriminator on PI

  11. Anaerobic facultative bacteria isolated from the gut of rabbits fed different diets. (United States)

    Canganella, F; Zirletta, G; Gualterio, L; Massa, S; Trovatelli, L D


    Anaerobic facultative bacteria colonizing the intestinal tract of conventional rabbits fed three different diets (standard pellet, hay and pellet/hay mixture) were enumerated in brain heart infusion agar. Colony counts recovered from homogenized samples of small intestine, caecum and rectum differed with reference to the diet given. Among anaerobic groups, identified from rabbit fed pellet/hay mixture, Enterococci (E. faecalis, E. avium, E. faecium and E. durans) represented the predominant flora. Enterobacters (E. cloacae and E. aerogenes) accounted for about 10 to 25% of the bacteria in the rectum and colon respectively, whereas Staphylococci (S. intermedius, S. epidermidis and S. lentus) represented 11% of the bacteria isolated from colon.


    Ziółkowska-Klinkosz, Marta; Kedzia, Anna; Meissner, Hhenry O; Kedzia, Andrzej W


    The study of the sensitivity to tea tree oil (Australian Company TTD International Pty. Ltd. Sydney) was carried out on 193 strains of anaerobic bacteria isolated from patients with various infections within the oral cavity and respiratory tracts. The susceptibility (MIC) of anaerobes was determined by means of plate dilution technique in Brucella agar supplemented with 5% defibrinated sheep blood, menadione and hemin. Inoculum contained 10(5) CFU per spot was cultured with Steers replicator upon the surface of agar with various tea tree oil concentrations or without oil (anaerobes growth control). Incubation the plates was performed in anaerobic jars under anaerobic conditions at 37 degrees C for 48 h. MIC was defined as the lowest concentrations of the essential oil completely inhibiting growth of anaerobic bacteria. Test results indicate, that among Gram-negative bacteria the most sensitive to essential oil were strains of Veillonella and Porphyromonas species. Essential oil in low concentrations (MIC in the range of = 0.12 - 0.5 mg/mL) inhibited growth of accordingly 80% and 68% strains. The least sensitive were strains of the genus Tannerella, Parabacteroides and Dialister (MIC 1.0 - 2.0 mg/mL). In the case of Gram-positive anaerobic bacteria the tea tree oil was the most active to strains of cocci of the genus Anaerococcus and Ruminococcus (MIC in range = 0.12 - 0.5 mg/mL) or strains of rods of the genus Eubacterium and Eggerthella (MIC = 0.25 mg/mL). Among Gram-positive rods the least sensitive were the strains of the genus Bifidobacterium ( MIC = 2.0 mg/mL). The tea tree oil was more active to Gram-positive than to Gram-negative anaerobic bacteria.

  13. New techniques for growing anaerobic bacteria: Experiments with Clostridium butyricum and Clostridium acetobutylicum

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    Adler, H.I.; Crow, W.D.; Hadden, C.T.; Hall, J.; Machanoff, R.


    Stable membrane fragments derived from Escherichia coli produce and maintain strict anaerobic conditions when added to liquid or solid bacteriological media. Techniques for growing Clostridium butyricum and Clostridium acetobutylicum in membrane containing media are described. Liquid cultures initiated by very small inocula can be grown in direct contact with air. In solid media, colonies develop rapidly from individual cells even without incubation in anaerobic jars or similar devices. Observations on growth rates, spontaneous mutations, radiation and oxygen sensitivity of anaerobic bacteria have been made using these new techniques.

  14. Mastoiditis and Gradenigo’s Syndrome with anaerobic bacteria

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    Jacobsen Chris


    Full Text Available Abstract Background Gradenigo’s syndrome is a rare disease, which is characterized by the triad of the following conditions: suppurative otitis media, pain in the distribution of the first and the second division of trigeminal nerve, and abducens nerve palsy. The full triad may often not be present, but can develop if the condition is not treated correctly. Case presentation We report a case of a 3-year-old girl, who presented with fever and left-sided acute otitis media. She developed acute mastoiditis, which was initially treated by intravenous antibiotics, ventilation tube insertion and cortical mastoidectomy. After 6 days the clinical picture was complicated by development of left-sided abducens palsy. MRI-scanning showed osteomyelitis within the petro-mastoid complex, and a hyper intense signal of the adjacent meninges. Microbiological investigations showed Staphylococcus aureus and Fusobacterium necrophorum. She was treated successfully with intravenous broad-spectrum antibiotic therapy with anaerobic coverage. After 8 weeks of follow-up there was no sign of recurrent infection or abducens palsy. Conclusion Gradenigo’s syndrome is a rare, but life-threatening complication to middle ear infection. It is most commonly caused by aerobic microorganisms, but anaerobic microorganisms may also be found why anaerobic coverage should be considered when determining the antibiotic treatment.

  15. Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing

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    Allyson Lee Brady


    Full Text Available Carbon monoxide (CO is a potential energy and carbon source for thermophilic bacteria in geothermal environments. Geothermal sites ranging in temperature from 45–65°C were investigated for the presence and activity of anaerobic CO-oxidizing bacteria. Anaerobic CO oxidation potentials were measured at up to 48.9 µmoles CO day-1 g (wet weight-1 within 5 selected sites. Active anaerobic carboxydotrophic bacteria were identified using 13CO DNA stable isotope probing (SIP combined with pyrosequencing of 16S rRNA genes amplified from labeled DNA. Bacterial communities identified in heavy DNA fractions were predominated by Firmicutes, which comprised up to 95% of all sequences in 13CO incubations. The predominant bacteria that assimilated 13C derived from CO were closely related (>98% to genera of known carboxydotrophs including Thermincola, Desulfotomaculum, Thermolithobacter and Carboxydocella, although a few species with lower similarity to known bacteria were also found that may represent previously unconfirmed CO-oxidizers. While the distribution was variable, many of the same OTUs were identified across sample sites from different temperature regimes. These results show that bacteria capable of using CO as a carbon source are common in geothermal springs, and that thermophilic carboxydotrophs are probably already quite well known from cultivation studies.

  16. Understanding how commensal obligate anaerobic bacteria regulate immune functions in the large intestine. (United States)

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


    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.


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    P. Owlia


    Full Text Available In this study 100 cases of advanced periodontitis were compared with a control group of 100 persons. The parameters were the depth of the periodontal pockets, radiographic images, presence of inflammatory cells and different types of anaerobic bacteria in the pockets. The depth of pocket was measured by a sterile probe and the presence of inflammatory cells was determined through sterile curettage. The smears were stained by Gimsa and Gram methods. For the purpose of microbiological studies, subgingival plaque samples were taken on paper points and were plated on brucella agar medium supplemented with rabbit blood, haemin and vitamin K1. The results indicated that with increasing depth of the pocket, the number of mixed anaerobic infections increases, and the presence of inflammatory cells especially polymorphonuclears is more prominent in comparison to the control group. As the pocket depth increases the conditions become more favourable for anaerobic bacteria and in consequence the incidence of isolation of these bacteria increases. On the other hand as the number of anaerobic bacteria and inflammatory cells and the secretion of destructive enzymes increases, the resultant injury to periodontal tissue increases.

  18. Immobilization of anaerobic bacteria on rubberized-coir for psychrophilic digestion of night soil. (United States)

    Dhaked, Ram Kumar; Ramana, Karna Venkat; Tomar, Arvind; Waghmare, Chandrakant; Kamboj, Dev Vrat; Singh, Lokendra


    Low-ambient temperatures, biodigesters due to low-growth rate of the constituent bacterial consortium. Immobilization of anaerobic bacteria has been attempted in the biodigester operating at 10 degrees C. Various matrices were screened and evaluated for the immobilization of bacteria in digesters. Anaerobic digestion of night soil was carried out with hydraulic retention time in the range of 9-18 days. Among the tested matrices, rubberized-coir was found to be the most useful at 10 degrees C with optimum hydraulic retention time of 15 days. Optimum amount of coir was found as 25 g/L of the working volume of biodigesters. Immobilization of bacteria on the coir was observed by scanning electron microscopy and fluorescent microscopy. The study indicates that rubberized-coir can be utilized to increase biodegradation of night soil at higher organic loading. Another advantage of using this matrix is that it is renewable and easily available in comparison to other synthetic polymeric matrices.

  19. Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions. (United States)

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


    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.

  20. Electron transfer in syntrophic communities of anaerobic bacteria and archaea

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    Stams, A.J.M.; Plugge, C.M.


    Interspecies electron transfer is a key process in methanogenic and sulphate-reducing environments. Bacteria and archaea that live in syntrophic communities take advantage of the metabolic abilities of their syntrophic partner to overcome energy barriers and break down compounds that they cannot dig

  1. Bacteremia due to anaerobic bacteria: epidemiology in a northern Bari Hospital, Italy

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    Maria Antonietta Distasi


    Full Text Available Background. Anaerobic bacteria are part of the commensal bacterial flora of skin and mucosae. Iatrogenic and pathological conditions altering this commensal relationship cause life-threatening diseases. Materials and Methods. We analysed the blood cultures sent to the microbiology of our hospital between 2008 and the first quarter of 2013 to measure the frequency of bacteraemia caused by anaerobia. We examined 3138 vials of blood cultures for anaerobia, inoculated following in-house standard procedures. The colonies grown in absence of air were subjected to biochemical analysis. The MICs of metronidazole for 23 of the 26 organisms was tested. Results. Twelve bacteria of the Bacteroides genus were identified, 9 Propionibacterium acnes, 1 Peptosctreptococcus micros, 1 Lactobacillus acidophilus, 1 Clostridium perfringens, 1 Prevotella oralis, 1 Eubacterium lentum. Conclusions. The analysis of the results suggests that the incidence of cultures positive to anaerobia was constant across the years. We note that advanced age, altered mucocutaneous tropism, alterations to the oral and intestinal bacterial flora intensify the risk of anaerobial pathogenicity. The analysis of the metronidazole-determined MIC suggests that the intestinal anaerobic flora responds well to therapy and prophylaxis with Metronidazole, while the anaerobic bacteria residing on skin and other mucosae are resistant. It is however hard to determine the clinical impact of anaerobic bacteremiae and their effect on the outcome of the patient, due to the scarcity of available clinical data.

  2. Complete genome sequence of the filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus

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    Larimer Frank W


    Full Text Available Abstract Background Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic phototrophic (FAP bacterium, and can grow phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria. Methods The complete genomic sequence of Cfl. aurantiacus has been determined, analyzed and compared to the genomes of other photosynthetic bacteria. Results Abundant genomic evidence suggests that there have been numerous gene adaptations/replacements in Cfl. aurantiacus to facilitate life under both anaerobic and aerobic conditions, including duplicate genes and gene clusters for the alternative complex III (ACIII, auracyanin and NADH:quinone oxidoreductase; and several aerobic/anaerobic enzyme pairs in central carbon metabolism and tetrapyrroles and nucleic acids biosynthesis. Overall, genomic information is consistent with a high tolerance for oxygen that has been reported in the growth of Cfl. aurantiacus. Genes for the chimeric photosystem, photosynthetic electron transport chain, the 3-hydroxypropionate autotrophic carbon fixation cycle, CO2-anaplerotic pathways, glyoxylate cycle, and sulfur reduction pathway are present. The central carbon metabolism and sulfur assimilation pathways in Cfl. aurantiacus are discussed. Some features of the Cfl. aurantiacus genome are compared with those of the Roseiflexus castenholzii genome. Roseiflexus castenholzii is a recently characterized FAP bacterium and phylogenetically closely related to Cfl

  3. Glycosaminoglycan-depolymerizing enzymes produced by anaerobic bacteria isolated from the human mouth. (United States)

    Tipler, L S; Embery, G


    A number of obligately anaerobic bacteria, some implicated in periodontal disease, were screened for their ability to produce enzymes capable of degrading hyaluronic acid and chondroitin-4-sulphate. Two screening methods were used following anaerobic incubation at 37 degrees C for 7 days. One involved incorporating the respective substrates and bovine-serum albumin into agar plates and, after incubation, flooding the plates with 2 M acetic acid. Clear zones were produced around colonies which produced enzymes capable of depolymerizing the substrates. The second was a sensitive spectrophotometric procedure based on the ability of certain bacteria to produce eliminase enzymes, which degrade the substrates to unsaturated products having a characteristic u.v. absorption at 232 nm. Strains of Bacteroides gingivalis and Bacteroides melaninogenicus degraded both substrates whereas Bacteroides asaccharolyticus degraded neither substrate by either method. Some bacteria gave negative results with the plate method whereas the more sensitive spectrophotometric assay proved positive. The number of anaerobic bacteria capable of degrading hyaluronic acid and chondroitin-4-sulphate in vitro may therefore have been underestimated in previous studies.

  4. Confocal laser scanning microscopy coupled to a spectrofluorometric detector as a rapid tool for determining the in vivo effect of metals on phototrophic bacteria. (United States)

    Burnat, Mireia; Diestra, Elia; Esteve, Isabel; Solé, Antonio


    In this paper, we determine for the first time the in vivo effect of heavy metals in a phototrophic bacterium. We used Confocal Laser Scanning Microscopy coupled to a spectrofluorometric detector as a rapid technique to measure pigment response to heavy-metal exposure. To this end, we selected lead and copper (toxic and essential metals) and Microcoleus sp. as the phototrophic bacterium because it would be feasible to see this cyanobacterium as a good biomarker, since it covers large extensions of coastal sediments. The results obtained demonstrate that, while cells are still viable, pigment peak decreases whereas metal concentration increases (from 0.1 to 1 mM Pb). Pigments are totally degraded when cultures were polluted with lead and copper at the maximum doses used (25 mM Pb(NO(3))(2) and 10 mM CuSO(4)). The aim of this study was also to identify the place of metal accumulation in Microcoleus cells. Element analysis of this cyanobacterium in the above mentioned conditions determined by Energy Dispersive X-ray microanalysis (EDX) coupled to Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), shows that Pb (but not Cu) accumulates externally and internally in cells.

  5. Biogas production from brewery spent grain enhanced by bioaugmentation with hydrolytic anaerobic bacteria. (United States)

    Čater, Maša; Fanedl, Lijana; Malovrh, Špela; Logar, Romana Marinšek


    Lignocellulosic substrates are widely available but not easily applied in biogas production due to their poor anaerobic degradation. The effect of bioaugmentation by anaerobic hydrolytic bacteria on biogas production was determined by the biochemical methane potential assay. Microbial biomass from full scale upflow anaerobic sludge blanket reactor treating brewery wastewater was a source of active microorganisms and brewery spent grain a model lignocellulosic substrate. Ruminococcus flavefaciens 007C, Pseudobutyrivibrio xylanivorans Mz5(T), Fibrobacter succinogenes S85 and Clostridium cellulovorans as pure and mixed cultures were used to enhance the lignocellulose degradation and elevate the biogas production. P. xylanivorans Mz5(T) was the most successful in elevating methane production (+17.8%), followed by the coculture of P. xylanivorans Mz5(T) and F. succinogenes S85 (+6.9%) and the coculture of C. cellulovorans and F. succinogenes S85 (+4.9%). Changes in microbial community structure were detected by fingerprinting techniques.

  6. Clinically significant anaerobic bacteria isolated from patients in a South African academic hospital: antimicrobial susceptibility testing. (United States)

    Naidoo, S; Perovic, O; Richards, G A; Duse, A G


    BACKGROUND. Increasing resistance to some antimicrobial agents among anaerobic bacteria has made susceptibility patterns less predictable. METHOD. This was a prospective study of the susceptibility data of anaerobic organisms isolated from clinical specimens from patients with suspected anaerobic infections from June 2005 until February 2007. Specimens were submitted to the microbiology laboratory at Charlotte Maxeke Johannesburg Academic Hospital, where microscopy, culture and susceptibility testing were performed the using E test® strip minimum inhibitory concentration method. Results were interpreted with reference to Clinical and Laboratory Standards Institute guidelines for amoxicillin-clavulanate, clindamycin, metronidazole, penicillin, ertapenem, cefoxitin, ceftriaxone, chloramphenicol and piperacillin-tazobactam. RESULTS. One hundred and eighty anaerobic isolates were submitted from 165 patients. The most active antimicrobial agents were chloramphenicol (100% susceptible), ertapenem (97.2%), piperacillin-tazobactam (99.4%) and amoxicillin-clavulanic acid (96.7%). Less active were metronidazole (89.4%), cefoxitin (85%), clindamycin (81.7%), ceftriaxone (68.3%) and penicillin (33.3%). CONCLUSION. Susceptibility testing should be performed periodically to identify emerging trends in resistance and to modify empirical treatment of anaerobic infections.



    Owlia, P.; Salari MH.; Saderi, H; Z. Kadkhoda


    In this study 100 cases of advanced periodontitis were compared with a control group of 100 persons. The parameters were the depth of the periodontal pockets, radiographic images, presence of inflammatory cells and different types of anaerobic bacteria in the pockets. The depth of pocket was measured by a sterile probe and the presence of inflammatory cells was determined through sterile curettage. The smears were stained by Gimsa and Gram methods. For the purpose of microbiological studies, ...

  8. [Necrotizing mucosal ulcers cause by anaerobic bacteria. Fusiform bacterial and spirochete infections]. (United States)

    Hollandt, J H; Hollandt, H


    Vincent's angina (Plaut-Vincent) is the most prominent disease caused by coinciding infections from fusibacteria and spirochaeta both belonging to obligate anaerobic bacteria. A possible symbiotic infection of both anaerobics may become manifest on the mucous membranes of the oral cavity and the oropharynx beside the tonsillas. The clinical outcome may be different and pose difficulties in the differential diagnosis. We report the case of a 29 year old female patient with necrotizing ulcera of the soft palate suspicious for stomatitis ulceromembranacea. In case necrotizing inflammations of the oral cavity area were to be found infections due to anaerobic bacteria should be considered mostly occurring as mixed infections. The correct identification by cultivation turns out to be difficult in that it requires special conditions. Furthermore, reliable detection of these bacteria necessitates careful collection and transport of patients specimens. In case of Fusospirochaetosis (Fusotreponematose) a specimen should be prepared for microscopic examination beside setting up a special culture. This is because the staining is the most suitable procedure for bacteril identification to support the clinical diagnosis of stomatitis ulceromembranacea.

  9. [Utility of MALDI-TOF MS for the identification of anaerobic bacteria]. (United States)

    Zárate, Mariela S; Romano, Vanesa; Nievas, Jimena; Smayevsky, Jorgelina


    The analysis by MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) has become a reference method for the identification of microorganisms in Clinical Microbiology. However, data on some groups of microorganisms are still controversial. The aim of this study is to determine the utility of MALDI-TOF MS for the identification of clinical isolates of anaerobic bacteria. One-hundred and six anaerobic bacteria isolates were analyzed by MALDI-TOF MS and by conventional biochemical tests. In those cases where identification by conventional methodology was not applicable or in the face of discordance between sequencing methodologies, 16 S rRNA gene sequence analysis was performed. The conventional method and MALDI-TOF MS agreed at genus and species level by 95.3 %. Concordance in gram-negative bacilli was 91.4% and 100% among gram-positive bacilli; there was also concordance both in the 8 isolates studied in gram-positive cocci and in the single gram-negative cocci included. The data obtained in this study demonstrate that MALDI-TOF MS offers the possibility of adequate identification of anaerobic bacteria.

  10. The anammoxosome organelle is crucial for the energy metabolism of anaerobic ammonium oxidizing bacteria. (United States)

    van Teeseling, Muriel C F; Neumann, Sarah; van Niftrik, Laura


    Anammox bacteria convert ammonium and nitrite to dinitrogen gas under anaerobic conditions to obtain their energy for growth. The anammox reaction was deemed impossible until its discovery in the early 1990s. Now, anammox bacteria are recognized as major players in the global nitrogen cycle and estimated to be responsible for up to 50% of the nitrogen in the air that we breathe. In addition, anammox bacteria are extremely valuable for wastewater treatment where they are applied for the removal of ammonium. Besides their importance in industry and the environment, anammox bacteria defy some basic biological concepts. Whereas most other bacteria have only one cell compartment, the cytoplasm, anammox bacteria have three independent cell compartments bounded by bilayer membranes, from out- to inside; the paryphoplasm, riboplasm and anammoxosome. The anammoxosome is the largest compartment of the anammox cell and is proposed to be dedicated to energy conservation. As such it would be analogous to the mitochondria of eukaryotes. This review will discuss the anammox cell plan in detail, with the main focus on the anammoxosome. The identity of the anammoxosome as a prokaryotic organelle and the importance of this organelle for anammox bacteria are discussed as well as challenges these bacteria face by having three independent cell compartments.

  11. O2-sensing and O2-dependent gene regulation in facultatively anaerobic bacteria. (United States)

    Unden, G; Becker, S; Bongaerts, J; Holighaus, G; Schirawski, J; Six, S


    Availability of O2 is one of the most important regulatory signals in facultatively anaerobic bacteria. Various two- or one-component sensor/regulator systems control the expression of aerobic and anaerobic metabolism in response to O2. Most of the sensor proteins contain heme or Fe as cofactors that interact with O2 either by binding or by a redox reaction. The ArcA/ArcB regulator of aerobic metabolism in Escherichia coli may use a different sensory mechanism. In two-component regulators, the sensor is located in the cytoplasmic membrane, whereas one-component regulators are located in the cytoplasm. Under most conditions, O2 can readily reach the cytoplasm and could provide the signal in the cytoplasm. The transcriptional regulator FNR of E. Coli controls the expression of many genes required for anaerobic metabolism in response to O2. Functional homologs of FNR are present in facultatively anaerobic Proteobacteria and presumably also in gram-positive bacteria. The target genes of FNR are mostly under multiple regulation by FNR and other regulators that respond to O2, nitrate, or glucose. FNR represents a 'one-component' sensor/regulator and contains Fe for signal perception. In response to O2 availability, FNR is converted reversibly from the aerobic (inactive) state to the anaerobic (active) state. Experiments suggest that the Fe cofactor is bound by four essential cysteine residues. The O2-triggered transformation between active and inactive FNR presumably is due to a redox reaction at the Fe cofactor, but other modes of interaction cannot be excluded. O2 seems to affect the site-specific DNA binding of FNR at target genes or the formation of an active transcriptional complex with RNA polymerase.

  12. Significance of anaerobes and oral bacteria in community-acquired pneumonia.

    Directory of Open Access Journals (Sweden)

    Kei Yamasaki

    Full Text Available BACKGROUND: Molecular biological modalities with better detection rates have been applied to identify the bacteria causing infectious diseases. Approximately 10-48% of bacterial pathogens causing community-acquired pneumonia are not identified using conventional cultivation methods. This study evaluated the bacteriological causes of community-acquired pneumonia using a cultivation-independent clone library analysis of the 16S ribosomal RNA gene of bronchoalveolar lavage specimens, and compared the results with those of conventional cultivation methods. METHODS: Patients with community-acquired pneumonia were enrolled based on their clinical and radiological findings. Bronchoalveolar lavage specimens were collected from pulmonary pathological lesions using bronchoscopy and evaluated by both a culture-independent molecular method and conventional cultivation methods. For the culture-independent molecular method, approximately 600 base pairs of 16S ribosomal RNA genes were amplified using polymerase chain reaction with universal primers, followed by the construction of clone libraries. The nucleotide sequences of 96 clones randomly chosen for each specimen were determined, and bacterial homology was searched. Conventional cultivation methods, including anaerobic cultures, were also performed using the same specimens. RESULTS: In addition to known common pathogens of community-acquired pneumonia [Streptococcus pneumoniae (18.8%, Haemophilus influenzae (18.8%, Mycoplasma pneumoniae (17.2%], molecular analysis of specimens from 64 patients with community-acquired pneumonia showed relatively higher rates of anaerobes (15.6% and oral bacteria (15.6% than previous reports. CONCLUSION: Our findings suggest that anaerobes and oral bacteria are more frequently detected in patients with community-acquired pneumonia than previously believed. It is possible that these bacteria may play more important roles in community-acquired pneumonia.

  13. A rapid method for the detection of tryptophanase in anaerobic bacteria. (United States)

    Karim, M R; Qadri, S M; Flournoy, D J


    A total of 633 anaerobic bacteria were examined for tryptophanase production using a rapid method which distinguishes within 5 to 180 minutes between anaerobes that contain tryptophanase and those that do not. Of the 196 tryptophanase-positive isolates tested, 99% showed tryptophanase activity within 2 hours as compared with 94.4% in 24 hours by a conventional method. A total of 299 tryptophanase-negative organisms were tested. Ninety three percent of these remained negative after 24 hours as compared with 95.3% when tested within a 24-h conventional method. Additional information was obtained on the sensitivity of this test and the time-dependent production of indole by tryptophanase.

  14. Ecology of aerobic anoxygenic phototrophs in aquatic environments. (United States)

    Koblížek, Michal


    Recognition of the environmental role of photoheterotrophic bacteria has been one of the main themes of aquatic microbiology over the last 15 years. Aside from cyanobacteria and proteorhodopsin-containing bacteria, aerobic anoxygenic phototrophic (AAP) bacteria are the third most numerous group of phototrophic prokaryotes in the ocean. This functional group represents a diverse assembly of species which taxonomically belong to various subgroups of Alpha-, Beta- and Gammaproteobacteria. AAP bacteria are facultative photoheterotrophs which use bacteriochlorophyll-containing reaction centers to harvest light energy. The light-derived energy increases their bacterial growth efficiency, which provides a competitive advantage over heterotrophic species. Thanks to their enzymatic machinery AAP bacteria are active, rapidly growing organisms which contribute significantly to the recycling of organic matter. This chapter summarizes the current knowledge of the ecology of AAP bacteria in aquatic environments, implying their specific role in the microbial loop.

  15. Colonizing the embryonic zebrafish gut with anaerobic bacteria derived from the human gastrointestinal tract. (United States)

    Toh, Michael C; Goodyear, Mara; Daigneault, Michelle; Allen-Vercoe, Emma; Van Raay, Terence J


    The zebrafish has become increasingly popular for microbiological research. It has been used as an infection model for a variety of pathogens, and is also emerging as a tool for studying interactions between a host and its resident microbial communities. The mouse microbiota has been transplanted into the zebrafish gut, but to our knowledge, there has been no attempt to introduce a bacterial community derived from the human gut. We explored two methods for colonizing the developing gut of 5-day-old germ-free zebrafish larvae with a defined anaerobic microbial community derived from a single human fecal sample. Both environmental exposure (static immersion) and direct microinjection into the gut resulted in the establishment of two species-Lactobacillus paracasei and Eubacterium limosum-from a community of 30 strains consisting of 22 anaerobic species. Of particular interest is E. limosum, which, as a strict anaerobe, represents a group of bacteria which until now have not been shown to colonize the developing zebrafish gut. Our success here indicates that further investigation of zebrafish as a tool for studying human gut microbial communities is warranted.

  16. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator. (United States)

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


    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).

  17. Anammox bacteria and the anaerobic oxidation of ammonium in the oxygen minimum zone off northern Chile (United States)

    Galán, Alexander; Molina, Verónica; Thamdrup, Bo; Woebken, Dagmar; Lavik, Gaute; Kuypers, Marcel M. M.; Ulloa, Osvaldo


    Anammox is the anaerobic oxidation of ammonium by nitrite or nitrate to yield N 2. This process, along with conventional denitrification, contributes to nitrogen loss in oxygen-deficient systems. Anammox is performed by a special group of bacteria belonging to the Planctomycetes phylum. However, information about the distribution, activity, and controlling factors of these anammox bacteria is still limited. Herein, we examine the phylogenetic diversity, vertical distribution, and activity of anammox bacteria in the coastal upwelling region and oxygen minimum zone off northern Chile. The phylogeny of anammox bacteria was studied using primers designed to specifically target 16S rRNA genes from Planctomycetes in samples taken during a cruise in 2004. Anammox bacteria-like sequences affiliated with Candidatus "Scalindua spp." dominated the 16S rRNA gene clone library. However, 62% of the sequences subgrouped separately within this cluster and together with a single sequence retrieved from the suboxic zone of the freshwater Lake Tanganyika. The vertical distribution and activity of anammox bacteria were explored through CARD-FISH (fluorescence in situ hybridization with catalyzed reporter deposition) and 15N labeling incubations, respectively, at two different open-ocean stations during a second cruise in 2005. Anammox bacterial CARD-FISH counts (up to 3000 cells ml -1) and activity (up to 5.75 nmol N 2 L -1 d -1) were only detected at the station subjected directly to the upwelling influence. Anammox cell abundance and activity were highest at 50 m depth, which is the upper part of the OMZ. In this layer, a high abundance of cyanobacteria and a marked nitrogen deficit were also observed. Thus, our results show the presence of a new subcluster within the marine anammox phylogeny and indicate high vertical variability in the abundance and activity of anammox bacteria that could be related to an intensification of carbon and nitrogen cycling in the upper part of the OMZ.

  18. Diversity and enrichment of nitrite-dependent anaerobic methane oxidizing bacteria from wastewater sludge. (United States)

    Luesken, Francisca A; van Alen, Theo A; van der Biezen, Erwin; Frijters, Carla; Toonen, Ger; Kampman, Christel; Hendrickx, Tim L G; Zeeman, Grietje; Temmink, Hardy; Strous, Marc; Op den Camp, Huub J M; Jetten, Mike S M


    Recently discovered microorganisms affiliated to the bacterial phylum NC10, named "Candidatus Methylomirabilis oxyfera", perform nitrite-dependent anaerobic methane oxidation. These microorganisms could be important players in a novel way of anaerobic wastewater treatment where ammonium and residual dissolved methane might be removed at the expense of nitrate or nitrite. To find suitable inocula for reactor startup, ten selected wastewater treatment plants (WWTPs) located in The Netherlands were screened for the endogenous presence of M. oxyfera using molecular diagnostic methods. We could identify NC10 bacteria with 98% similarity to M. oxyfera in nine out of ten WWTPs tested. Sludge from one selected WWTP was used to start a new enrichment culture of NC10 bacteria. This enrichment was monitored using specific pmoA primers and M. oxyfera cells were visualized with fluorescence oligonucleotide probes. After 112 days, the enrichment consumed up to 0.4 mM NO(2)(-) per day. The results of this study show that appropriate sources of biomass, enrichment strategies, and diagnostic tools existed to start and monitor pilot scale tests for the implementation of nitrite-dependent methane oxidation in wastewater treatment at ambient temperature.

  19. Degradation of phenolic contaminants in ground water by anaerobic bacteria: St. Louis Park, Minnesota (United States)

    Ehrlich, G.G.; Goerlitz, D.F.; Godsy, E.M.; Hult, M.F.


    Coal-tar derivatives from a coal-tar distillation and wood-treating plant that operated from 1918 to 1972 at St. Louis Park, Minnesota contaminated the near-surface ground water. Solutions of phenolic compounds and a water-immiscible mixture of polynuclear aromatic compounds accumulated in wetlands near the plant site and entered the aquifer. The concentration of phenolic compounds in the aqueous phase under the wetlands is about 30 mg/1 but decreases to less than 0.2 mg/1 at a distance of 430 m immediately downgradient from the source. Concentrations of naphthalene (the predominant polynuclear compound in the ground water) and sodium (selected as a conservative tracer) range from about 20 mg/1 and 430 mg/1 in the aqueous phase at the source to about 2 mg/1 and 120 mg/1 at 430 m downgradient, respectively. Phenolic compounds and naphthalene are disappearing faster than expected if only dilution were occurring. Sorption of phenolic compounds on aquifer sediments is negligible but naphthalene is slightly sorbed. Anaerobic biodegradation of phenolic compounds is primarily responsible for the observed attenuation. Methane was found only in water samples from the contaminated zone (2-20 mg/1). Methane-producing bacteria were found only in water from the contaminated zone. Methane was produced in laboratory cultures of contaminated water inoculated with bacteria from the contaminated zone. Evidence for anaerobic biodegradation of naphthalene under either field or laboratory conditions was not obtained.

  20. Cultivation of nitrite-dependent anaerobic methane-oxidizing bacteria: impact of reactor configuration. (United States)

    Hu, Baolan; He, Zhanfei; Geng, Sha; Cai, Chen; Lou, Liping; Zheng, Ping; Xu, Xinhua


    Nitrite-dependent anaerobic methane oxidation (n-damo) is mediated by bacteria that anaerobically oxidize methane coupled with nitrite reduction and is a potential bioprocess for wastewater treatment. In this work, the effect of reactor configuration on n-damo bacterial cultivation was investigated. A magnetically stirred gas lift reactor (MSGLR), a sequencing batch reactor (SBR), and a continuously stirred tank reactor (CSTR) were selected to cultivate the bacteria. Microbial community was monitored by using quantitative PCR, 16S rRNA gene sequencing, pmoA gene sequencing, and fluorescence in situ hybridization (FISH). The effects of substrate inhibition, methane mass transfer, and biomass washout in the three reactors were focused on. The results indicated that the MSGLR had the best performance among the three reactor systems, with the highest total and specific n-damo activities. Its maximum volumetric nitrogen removal rate was up to 76.9 mg N L(-1) day(-1), which was higher than previously reported values (5.1-37.8 mg N L(-1) d(-1)).

  1. Conversion of hemicelluloses and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)



    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmosphere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. Thermophilic anaerobic ethanol producing bacteria can be used for fermentation of the hemicelluloses fraction of lignocellulosic biomass. However, physiological studies of thermophilic anaerobic bacteria have shown that the ethanol yield decreases at increasing substrate concentration. The biochemical limitations causing this phenomenon are not known in detail. Physiological and biochemical studies of a newly characterized thermophilic anaerobic ethanol producing bacterium, Thermoanaerobacter mathranii, was performed. This study included extraction of intracellular metabolites and enzymes of the pentose phosphate pathway and glycolysis. These studies revealed several bottlenecks in the D-xylose metabolism. This knowledge makes way for physiological and genetic engineering of this strain to improve the ethanol yield and productivity at high concentration of D-xylose. (au)

  2. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Zeikus, J.G.; Jain, M.


    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  3. Analysis of cbbL, nifH, and pufLM in Soils from the Sør Rondane Mountains, Antarctica, Reveals a Large Diversity of Autotrophic and Phototrophic Bacteria. (United States)

    Tahon, Guillaume; Tytgat, Bjorn; Stragier, Pieter; Willems, Anne


    Cyanobacteria are generally thought to be responsible for primary production and nitrogen fixation in the microbial communities that dominate Antarctic ecosystems. Recent studies of bacterial communities in terrestrial Antarctica, however, have shown that Cyanobacteria are sometimes only scarcely present, suggesting that other bacteria presumably take over their role as primary producers and diazotrophs. The diversity of key genes in these processes was studied in surface samples from the Sør Rondane Mountains, Dronning Maud Land, using clone libraries of the large subunit of ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL, cbbM) and dinitrogenase-reductase (nifH) genes. We recovered a large diversity of non-cyanobacterial cbbL type IC in addition to cyanobacterial type IB, suggesting that non-cyanobacterial autotrophs may contribute to primary production. The nifH diversity recovered was predominantly related to Cyanobacteria, particularly members of the Nostocales. We also investigated the occurrence of proteorhodopsin and anoxygenic phototrophy as mechanisms for non-Cyanobacteria to exploit solar energy. While proteorhodopsin genes were not detected, a large diversity of genes coding for the light and medium subunits of the type 2 phototrophic reaction center (pufLM) was observed, suggesting for the first time, that the aerobic photoheterotrophic lifestyle may be important in oligotrophic high-altitude ice-free terrestrial Antarctic habitats.

  4. Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures. (United States)

    Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D


    The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival.

  5. Quantification of anaerobic ammonium-oxidizing bacteria in enrichment cultures by quantitative competitive PCR

    Institute of Scientific and Technical Information of China (English)

    HAO Chun; WANG Huan; LIU Qinhua; LI Xudong


    The anaerobic ammonium-oxidizing (ANAMMOX) bacteria were enriched from a sequencing batch biofilm reactor (SBBR) biofilm.We successfully developed a quantitative competitive polymerase chain reaction (QC-PCR) system to detect and quantify ANAMMOX bacteria in environmental samples.For QC-PCR system,PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used.The quantification range of this system was 4 orders of magnitude,from 10~3 to 10~6 copies per PCR,corresponding to the detection limit of 300 target copies per mL.A 312-bp internal standard (IS) was constructed,which showed very similar amplification efficiency with the target amxC fragment (349 bp) over 4 orders of magnitude (10~3-10~6).The linear regressions were obtained with a R~2 of 0.9824 for 10~3 copies,R~2 of 0.9882 for 10~4 copies,0.9857 for 10~5 copies and 0.9899 for 10~6 copies.Using this method,we quantified ANAMMOX bacteria in a shortcut nitrification/denitrification-anammox system which is set for piggery wastewater treatment.

  6. Distribution and activity of anaerobic ammonium-oxidising bacteria in natural freshwater wetland soils. (United States)

    Shen, Li-dong; Wu, Hong-sheng; Gao, Zhi-qiu; Cheng, Hai-xiang; Li, Ji; Liu, Xu; Ren, Qian-qi


    Anaerobic ammonium oxidation (anammox) process plays a significant role in the marine nitrogen cycle. However, the quantitative importance of this process in nitrogen removal in wetland systems, particularly in natural freshwater wetlands, is still not determined. In the present study, we provided the evidence of the distribution and activity of anammox bacteria in a natural freshwater wetland, located in southeastern China, by using (15)N stable isotope measurements, quantitative PCR assays and 16S rRNA gene clone library analysis. The potential anammox rates measured in this wetland system ranged between 2.5 and 25.5 nmol N2 g(-1) soil day(-1), and up to 20% soil dinitrogen gas production could be attributed to the anammox process. Phylogenetic analysis of 16S rRNA genes showed that anammox bacteria related to Candidatus Brocadia, Candidatus Kuenenia, Candidatus Anammoxoglobus and two novel anammox clusters coexisted in the collected soil cores, with Candidatus Brocadia and Candidatus Kuenenia being the dominant anammox genera. Quantitative PCR of hydrazine synthase genes showed that the abundance of anammox bacteria varied from 2.3 × 10(5) to 2.2 × 10(6) copies g(-1) soil in the examined soil cores. Correlation analyses suggested that the soil ammonium concentration had significant influence on the activity of anammox bacteria. On the basis of (15)N tracing technology, it is estimated that a total loss of 31.1 g N m(-2) per year could be linked the anammox process in the examined wetland.

  7. Nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria with C2/C3 fatty acid in upflow anaerobic sludge blanket reactors. (United States)

    Liang, Yuhai; Li, Dong; Zhang, Xiaojing; Zeng, Huiping; Yang, Yin; Zhang, Jie


    In anaerobic ammonium oxidation (Anammox) process, a harsh ratio of nitrite to ammonia in influent was demanded, and the max nitrogen removal efficiency could only achieve to 89%, both of which limited the development of Anammox. The aim of this work was to study the nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria (AAOB) with C2/C3 fatty acid in upflow anaerobic sludge blanket (UASB) reactors. In this study, organotrophic AAOB was successfully enriched by adding acetate and propionate with the total organic carbon to nitrogen (TOC/N) ratio of 0.1. In the condition of low substrate, the TN removal efficiency reached 90%, with the effluent TN of around 11.8 mg L(-1). After the addition of acetate and propionate, the predominant species in Anammox granular sludge transformed to Candidatus Jettenia that belonging to organotrophic AAOB from the Candidatus Kuenenia relating to general AAOB.

  8. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan


    A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria....... The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia...

  9. Adaptation of Bacteria of Anaerobic Digestion to Higher Salinity for the Application to Microbial Enhanced Oil Recovery

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Ivanova, Yanina; Spirov, Pavel

    g/L in the volume of 350 g/L. To revitalize bacteria and activate gas production, 200 mL salty water and 5 mL molasses were added. On the 6th day of the experiment, the maximum production was 1300 mL at 90 g/L and the minimum of 400 mL at 80 g/L. The experiment showed that bacteria of anaerobic...

  10. Anaerobic benzene degradation by Gram-positive sulfate-reducing bacteria. (United States)

    Abu Laban, Nidal; Selesi, Drazenka; Jobelius, Carsten; Meckenstock, Rainer U


    Despite its high chemical stability, benzene is known to be biodegradable with various electron acceptors under anaerobic conditions. However, our understanding of the initial activation reaction and the responsible prokaryotes is limited. In the present study, we enriched a bacterial culture that oxidizes benzene to carbon dioxide under sulfate-reducing conditions. Community analysis using terminal restriction fragment length polymorphism, 16S rRNA gene sequencing and FISH revealed 95% dominance of one phylotype that is affiliated to the Gram-positive bacterial genus Pelotomaculum showing that sulfate-reducing Gram-positive bacteria are involved in anaerobic benzene degradation. In order to get indications of the initial activation mechanism, we tested the substrate utilization, performed cometabolism tests and screened for putative metabolites. Phenol, toluene, and benzoate could not be utilized as alternative carbon sources by the benzene-degrading culture. Cometabolic degradation experiments resulted in retarded rates of benzene degradation in the presence of phenol whereas toluene had no effect on benzene metabolism. Phenol, 2-hydroxybenzoate, 4-hydroxybenzoate, and benzoate were identified as putative metabolites in the enrichment culture. However, hydroxylated aromatics were shown to be formed abiotically. Thus, the finding of benzoate as an intermediate compound supports a direct carboxylation of benzene as the initial activation mechanism but additional reactions leading to its formation cannot be excluded definitely.

  11. Acetobacterium, a new genus of hydrogen-oxidizing, carbon dioxide-reducing, anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Balch, W.E.; Schoberth, S.; Tanner, R.S.; Wolfe, R.S.


    A new genus of fastidiously anaerobic bacteria which produce a homoacetic fermentation is described. Cells are gram-positive, oval-shaped, short rods which are actively motile by means of one or two subterminal flagella. Hydrogen is oxidized, and carbon dioxide is reduced to acetic acid. Organic substrates which are fermented in a mineral medium include frutose, glucose, lactate, glycerate, and formate. Pantothenate is required as a growth factor. The deoxyribonucleic acid base composition of the type species is 39 mol% guanine plus cytosine. The name Acetobacterium is proposed for this new genus, which is tentatively placed in the family Propionibacteriaceae. The type species, Acetobacterium woodii sp. nov., is named in honor of Harland G. Wood. The type strain of A. woodii is WB1 (= ATCC 29683 and DSM 1030).

  12. 16S rRNA gene sequencing in routine identification of anaerobic bacteria isolated from blood cultures

    DEFF Research Database (Denmark)

    Justesen, Ulrik Stenz; Skov, Marianne Nielsine; Knudsen, Elisa;


    A comparison between conventional identification and 16S rRNA gene sequencing of anaerobic bacteria isolated from blood cultures in a routine setting was performed (n = 127). With sequencing, 89% were identified to the species level, versus 52% with conventional identification. The times...

  13. The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium

    NARCIS (Netherlands)

    Santos, dos A.B.; Cervantes, F.J.; Madrid, de M.P.; Bok, de F.A.M.; Stams, A.J.M.; Lier, van J.B.


    The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium was studied. Additionally, the effects of different electron-donating substrates and the redox mediator riboflavin on dye reduction were assessed by using either a methanoge

  14. Candidatus "Scalindua brodaea", spec. nov., Candidatus "Scalindua wagneri", spec. nov., two new species of anaerobic ammonium oxidizing bacteria

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schmid, M.; Walsh, K.; Webb, R.; Rijpstra, W.I.C.; Pas-Schoonen, K. van de; Verbruggen, M.J.; Hill, T.; Moffett, B.; Fuerst, J.; Schouten, S.; Harris, James; Shaw, P.; Jetten, M.S.M.; Strous, M.


    Anaerobic ammonium oxidation (anammox) is both a promising process in wastewater treatment and a long overlooked microbial physiology that can contribute significantly to biological nitrogen cycling in the world's oceans. Anammox is mediated by a monophyletic group of bacteria that branches deeply i

  15. Evaluating primers for profiling anaerobic ammonia oxidizing bacteria within freshwater environments.

    Directory of Open Access Journals (Sweden)

    Puntipar Sonthiphand

    Full Text Available Anaerobic ammonia oxidizing (anammox bacteria play an important role in transforming ammonium to nitrogen gas and contribute to fixed nitrogen losses in freshwater environments. Understanding the diversity and abundance of anammox bacteria requires reliable molecular tools, and these are not yet well established for these important Planctomycetes. To help validate PCR primers for the detection of anammox bacteria within freshwater ecosystems, we analyzed representative positive controls and selected samples from Grand River and groundwater sites, both from Ontario, Canada. The objectives of this study were to identify a suitable anammox denaturing gradient gel electrophoresis (DGGE fingerprint method by using GC-clamp modifications to existing primers, and to verify the specificity of anammox-specific primers used for DGGE, cloning and qPCR methods. Six primer combinations were tested from four published primer sets (i.e. A438f/A684r, Amx368f/Amx820r, An7f/An1388r, and Pla46/1392r for both direct and nested PCR amplifications. All PCR products were run subsequently on DGGE gels to compare the resulting patterns. Two anammox-specific primer combinations were also used to generate clone libraries and quantify anammox bacterial 16S rRNA genes with qPCR. The primer set A438f/A684r was highly specific to anammox bacteria, provided reliable DGGE fingerprints and generated a high proportion of anammox-related clones. A second primer set (Amx368f/Amx820r was anammox specific, based on clone library analysis, but PCR products from different candidate species of anammox bacteria resolved poorly using DGGE analysis. Both DGGE and cloning results revealed that Ca. Brocadia and an uncharacterized anammox bacterial cluster represented the majority of anammox bacteria found in Grand River sediment and groundwater samples, respectively. Together, our results demonstrate that although Amx368f/Amx820r was useful for anammox-specific qPCR and clone library

  16. Evaluating primers for profiling anaerobic ammonia oxidizing bacteria within freshwater environments. (United States)

    Sonthiphand, Puntipar; Neufeld, Josh D


    Anaerobic ammonia oxidizing (anammox) bacteria play an important role in transforming ammonium to nitrogen gas and contribute to fixed nitrogen losses in freshwater environments. Understanding the diversity and abundance of anammox bacteria requires reliable molecular tools, and these are not yet well established for these important Planctomycetes. To help validate PCR primers for the detection of anammox bacteria within freshwater ecosystems, we analyzed representative positive controls and selected samples from Grand River and groundwater sites, both from Ontario, Canada. The objectives of this study were to identify a suitable anammox denaturing gradient gel electrophoresis (DGGE) fingerprint method by using GC-clamp modifications to existing primers, and to verify the specificity of anammox-specific primers used for DGGE, cloning and qPCR methods. Six primer combinations were tested from four published primer sets (i.e. A438f/A684r, Amx368f/Amx820r, An7f/An1388r, and Pla46/1392r) for both direct and nested PCR amplifications. All PCR products were run subsequently on DGGE gels to compare the resulting patterns. Two anammox-specific primer combinations were also used to generate clone libraries and quantify anammox bacterial 16S rRNA genes with qPCR. The primer set A438f/A684r was highly specific to anammox bacteria, provided reliable DGGE fingerprints and generated a high proportion of anammox-related clones. A second primer set (Amx368f/Amx820r) was anammox specific, based on clone library analysis, but PCR products from different candidate species of anammox bacteria resolved poorly using DGGE analysis. Both DGGE and cloning results revealed that Ca. Brocadia and an uncharacterized anammox bacterial cluster represented the majority of anammox bacteria found in Grand River sediment and groundwater samples, respectively. Together, our results demonstrate that although Amx368f/Amx820r was useful for anammox-specific qPCR and clone library analysis, A438f/A684r

  17. Conversion of hemicellulose and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Peter


    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmoshpere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. The need for a microorganism able to ferment D-xylose is therefore apparent. Thermophilic anaerobic ethanol producing bacteria can therefore be considered for fermentation of D-xylose. Screening of 130 thermophilic anaerobic bacterial strains, from hot-springs, mesophilic and thermophilic biogas plants, paper pulp industries and brewery waste, were examined for production of ethanol from D-xylose and wet-oxidized hemicellulose hydrolysate. Several strains were isolated and one particular strain was selected for best performance during the screening test. This strain was characterized as a new species, Thermoanaerobacter mathranii. However, the ethanol yield on wet-oxidized hemicellulose hydrolysate was not satisfactory. The bacterium was adapted by isolation of mutant strains, now resistant to the inhibitory compounds present in the hydrolysate. Growth and ethanol yield

  18. Electricity generation by anaerobic bacteria and anoxic sediments from hypersaline soda lakes (United States)

    Miller, L.G.; Oremland, R.S.


    Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However, these cultures grew equally well without added arsenate using the MFC anode as their electron acceptor, and in the process oxidized lactate more efficiently. The decrease in electricity generation by consumption of added alternative electron acceptors (i.e. arsenate) which competed with the anode for available electrons proved to be a useful indicator of microbial activity and hence life in the fuel cells. Shaken sediment slurries from these two lakes also generated electricity, with or without added lactate. Hydrogen added to sediment slurries was consumed but did not stimulate electricity production. Finally, electricity was generated in statically incubated "intact" sediment cores from these lakes. More power was produced in sediment from Mono Lake than from Searles Lake, however microbial fuel cells could detect low levels of metabolism operating under moderate and extreme conditions of salt stress. ?? 2008 US Government.

  19. Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xuefei; REN Nanqi


    In this study,the two-stage upflow anaerobic sludge blanket(UASB)system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater.The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated.The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor.Apparently,these were not the advisable pH levels that common metha nogenic bacteria could accept.The methanogenic bacteria of the system,viz.Methanosarcina barkeri,had some acid resistance and could still degrade methanol at pH 5.0.If the methanogenic bacteria were trained further,their acid resistance would be improved somewhat.Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5.The performance of granular sludge was attributed to its structure,bacteria species,and the distribution of bacterium inside the granule.

  20. Phototrophic pigment production with microalgae

    NARCIS (Netherlands)

    Mulders, K.J.M.



    Microalgal pigments are regarded as natural alternatives for food colorants. To facilitate optimization of microalgae-based pigment production, this thesis aimed to obtain key insights in the pigment metabolism of phototrophic microalgae, with the main  focus

  1. Microbial ecology of phototrophic biofilms

    NARCIS (Netherlands)

    Roeselers, G.


    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic

  2. Anaerobic ammonium-oxidizing (anammox) bacteria and associated activity in fixed-film biofilters of a marine recirculating aquaculture system. (United States)

    Tal, Yossi; Watts, Joy E M; Schreier, Harold J


    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems.

  3. Distribution of secretory inhibitor of platelet microbiddal protein among anaerobic bacteria isolated from stool of children with diarrhea

    Institute of Scientific and Technical Information of China (English)

    Iuri B Ivanov; Viktor A Gritsenko


    AIM: To study the secretory inhibitor of platelet microbicidal protein (SIPHP) phenotypes of faecal anaerobic isolates from patients with diarrhea.METHODS: Faecal isolates of anaerobic bacteria(B.fragiliS,n=42; B.longum,n=70;A.israelii,n=21;E.lentum,n=12) from children with diarrhea were tested.SlPHP production was tested by inhibition of platelet microbicidal protein (PHP) bioactivity against B.subtilis and was expressed as percentage of inhibition of PMP bactericidal activity.RESULTS: Among anaerobic isolates 80% of B.Iongum strains,85.7% of A.israelii strains,50%of E.lentum strains and 92.86% of B.fragilis strains were SIPMP-positive.The isolated anaerobic organisms demonstrated SIPHP production at a mean level of 13.8%±0.7%,14.7%±1.8%,3.9%±0.9% (P<0.05) and 26.8%±7.5% (P<0.05) for bifidobacteria,A.israelii,E.lentum and B.fragilis,respectively.CONCLUSION: Data from the present study may have significant implications in understanding the pathogenesis of microecological disorders in the intestine,as well as for future improvement in the prevention and therapy of anaerobe-associated infections.

  4. Sodium ion pumps and hydrogen production in glutamate fermenting anaerobic bacteria. (United States)

    Boiangiu, Clara D; Jayamani, Elamparithi; Brügel, Daniela; Herrmann, Gloria; Kim, Jihoe; Forzi, Lucia; Hedderich, Reiner; Vgenopoulou, Irini; Pierik, Antonio J; Steuber, Julia; Buckel, Wolfgang


    Anaerobic bacteria ferment glutamate via two different pathways to ammonia, carbon dioxide, acetate, butyrate and molecular hydrogen. The coenzyme B12-dependent pathway in Clostridium tetanomorphum via 3-methylaspartate involves pyruvate:ferredoxin oxidoreductase and a novel enzyme, a membrane-bound NADH:ferredoxin oxidoreductase. The flavin- and iron-sulfur-containing enzyme probably uses the energy difference between reduced ferredoxin and NADH to generate an electrochemical Na+ gradient, which drives transport processes. The other pathway via 2-hydroxyglutarate in Acidaminococcus fermentans and Fusobacterium nucleatum involves glutaconyl-CoA decarboxylase, which uses the free energy of decarboxylation to generate also an electrochemical Na+ gradient. In the latter two organisms, similar membrane-bound NADH:ferredoxin oxidoreductases have been characterized. We propose that in the hydroxyglutarate pathway these oxidoreductases work in the reverse direction, whereby the reduction of ferredoxin by NADH is driven by the Na+ gradient. The reduced ferredoxin is required for hydrogen production and the activation of radical enzymes. Further examples show that reduced ferredoxin is an agent, whose reducing energy is about 1 ATP 'richer' than that of NADH.

  5. Optimization of biohydrogen production from beer lees using anaerobic mixed bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Maojin; Yuan, Zhuliang; Zhi, Xiaohua; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190 (China)


    Beer lees are the main by-product of the brewing industry. Biohydrogen production from beer lees using anaerobic mixed bacteria was investigated in this study, and the effects of acidic pretreatment, initial pH value and ferrous iron concentration on hydrogen production were studied at 35 C in batch experiments. The hydrogen yield was significantly enhanced by optimizing environmental factors such as hydrochloric acid (HCl) pretreatment of substrate, initial pH value and ferrous iron concentration. The optimal environmental factors of substrate pretreated with 2% HCl, pH = 7.0 and 113.67 mg/l Fe{sup 2+} were observed. A maximum cumulative hydrogen yield of 53.03 ml/g-dry beer lees was achieved, which was approximately 17-fold greater than that in raw beer lees. In addition, the degradation efficiency of the total reducing sugar, and the contents of hemicellulose, cellulose, lignin and metabolites are presented, which showed a strong dependence on the environmental factors. (author)

  6. Stoke's and anti-Stoke's characteristics of anaerobic and aerobic bacterias at excitation of fluorescence by low-intensity red light: I. Research of anaerobic bacterias (United States)

    Masychev, Victor I.; Alexandrov, Michail T.


    Biopsy or photo dynamic therapy of tumors are usually investigated by fluorescent diagnostics methods. Information on modified method of fluorescence diagnostics of inflammatory diseases is represented in this research. Anaerobic micro organisms are often the cause of these pathological processes. These micro organisms also accompany disbiotic processes in intestines.

  7. Detection of periodontopathogenic bacteria in pregnant women by traditional anaerobic culture method and by a commercial molecular genetic method. (United States)

    Urbán, Edit; Terhes, Gabriella; Radnai, Márta; Gorzó, István; Nagy, Elisabeth


    To culture facultative and strict anaerobic bacteria is a well-established method for analyzing subgingival plaque samples. Micro-IDent and micro-IDent Plus (HAIN Lifescience GmbH, Nehren, Germany) tests are two commercially available rapid PCR-based methods for the identification and quantification of putative periodontopathogen bacteria. In this study, we compared these commercial PCR-based hybridization methods with conventional anaerobic culture technique. A total of 36 subgingival plaque samples were collected from periodontal pockets of pregnant women with chronic localized periodontitis. Aliquots of these samples were evaluated with species-specific probes provided by micro-IDent and micro-IDent Plus tests simultaneously, and from the same samples anaerobic and capnophylic bacteria were cultured on selective media. The overall agreement between both methods was excellent for Eubacterium nodatum, Tannerella forsythia and Porphyromonas gingivalis (97-92%), fair for Capnocytophaga sp, Eikenella corrodens, Actinobacillus actinomycetemcomitans, and Prevotella intermedia (91-89%) and poor for Fusobacterium nucleatum, Parvimonas micra (Micromonas micros), and Campylobacter rectus (86-78%). Discrepancies in the results may be explained by inability of culture method to distinguish between closely related taxa (e.i P. intermedia/Prevotella. nigrescens), and problems of keeping periodontopathogen bacteria viable, which is required for successful detection by standard culture method. Nucleic acid-based methods may replace cultivation method as frequently used methods in microbiological diagnosis of progressive periodontitis, thus micro-IDent and micro-IDent Plus tests can be recommended where culture of periodontopathogenic bacteria is not performed in routine microbiology laboratories to analyze subgingival plaque samples.

  8. [First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología]. (United States)

    Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C


    Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown.

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

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


    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.

  10. 新型OxyPlateTM厌氧系统隔离眼部厌氧菌的评估%Evaluation of the new OxyPlateTM Anaerobic System for the isolation of ocular anaerobic bacteria

    Institute of Scientific and Technical Information of China (English)

    Emily K. Deschler; Paul P. Thompson; Regis Paul Kowalski


    目的:厌氧细菌可引起眼部感染,我们测试OxyPlateTM厌氧系统(OxyPlateTM Anaerobic System,OXY)隔离可引起眼部疾病的厌氧细菌.方法:OXY不需要直接的厌氧条件(比如厌氧袋,罐),将其与常规的厌氧袋培养基相比.琼脂培养基上眼部厌氧细菌菌株在好氧和厌氧条件下(厌氧袋)行标准的菌落计数:(1)OXY(好氧);(2)5%羊血(sheep blood,SB);(3)巧克力琼脂;(4)Schaedler琼脂.测试的眼部体外培养细菌来自眼内炎,泪囊炎,包括10个丙酸杆菌和3个放线菌种类.在每个培养条件下,每个细菌菌落计数隔离,排名从大到小,并在非参数比较下确定最佳的培养条件.结果:所有的厌氧条件对于厌氧菌株呈阳性反应.厌氧菌在有氧条件下的SB和Schaedler的琼脂中无法增长.痤疮丙酸杆菌在巧克力琼脂中生长稀疏.作为一种厌氧系统,在厌氧袋SB分离比OXY(P=0.0028)和巧克力琼脂(P=0.0028)分离出更多的菌落数.结论:虽然OXY经测试并没比其他的厌氧系统更高效,它似乎是一个合理隔离厌氧细菌的替代方法.其琼脂培养基在一个专门设计的盘并不需要厌氧袋使得OXY优于其他厌氧系统.%AIM: Anaerobic bacteria can cause ocular infections. We tested the OxyPlateTM Anaerobic System (OXY) to isolate pertinent anaerobic bacteria that can cause ocular disease.METHODS: OXY, which does not require direct anaerobic conditions (i.e. bags, jars), was compared to conventional isolation of incubating culture media in anaerobic bags. Standard colonies counts were performed on anaerobic ocular bacterial isolates under aerobic and anaerobic conditions (anaerobic bags) using agar media: 1) OXY (aerobic only), 2) 5% sheep blood (SB), 3) Chocolate, and 4) Schaedler. The bacteria tested were de-identified ocular isolates cultured from endophthalmitis and dacryocystitis that include 10 Propionibacterium acnes and 3 Actinomyces species. The colony counts for each bacteria isolate, on each

  11. Comparative study of biological hydrogen production by pure strains and consortia of facultative and strict anaerobic bacteria. (United States)

    Hiligsmann, Serge; Masset, Julien; Hamilton, Christopher; Beckers, Laurent; Thonart, Philippe


    In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO(2) and another gaseous compound such as hydrogen or methane. This method was validated and experimented for the characterisation of the biochemical hydrogen potential of different pure strains and mixed cultures of hydrogen-producing bacteria (HPB) growing on glucose. The experimental results compared the hydrogen production yield of 19 different pure strains and sludges: facultative and strict anaerobic HPB strains along with anaerobic digester sludges thermally pre-treated or not. Significant yields variations were recorded even between different strains of the same species by i.e. about 20% for three Clostridium butyricum strains. The pure Clostridium butyricum and pasteurianum strains achieved the highest yields i.e. up to 1.36 mol H(2)/mol glucose compared to the yields achieved by the sludges and the tested Escherichia and Citrobacter strains.

  12. An automated blood culture system: the detection of anaerobic bacteria using a Malthus Microbiological Growth Analyser. (United States)

    McMaster, J P; Barr, J G; Campbell, R R; Bennett, R B; Smyth, E T


    The Malthus Microbiological Growth Analyser has proved to be sensitive in detecting conductivity changes due to anaerobic metabolism in a number of widely used blood culture media. Freshly prepared cooked meat media and Thiol medium yielded the greatest gross conductivity changes, and were more sensitive of anaerobic metabolism than other media. Failure of the instrument to detect anaerobic metabolism was a problem particularly associated with growth in the thioglycollate medium. False positive detections of growth were attributed to a number of factors including electrode instability (6.0%) and bacterial contamination (8.75%).

  13. Degradation Action of the Anaerobic Bacteria and Oxygen to the Polymer

    Institute of Scientific and Technical Information of China (English)

    LU Xiang-Guo; ZHANG Ke


    Oxygen could prohibit anaerobic bacterium in the produced water and degrade the polymer molecular chains.Aiming at problems making up aerobic polymer solution by the produced water in Daqing Oil Field, some evaluations were done on the viscosity characteristics of polymer solution and bactericide in anaerobic and aerobic environments. Reasonable aerobic concentration of the produced water was obtained. The experimental results indicate that the viscosity of polymer solution confected by the produced water in the aerobic environment is higher than that of the polymer solution confected by the produced water in the anaerobic environment, and the reasonable ments, but the sterilization effect is better in the aerobic environment.

  14. Simultaneous enrichment of denitrifying anaerobic methane-oxidizing microorganisms and anammox bacteria in a hollow-fiber membrane biofilm reactor. (United States)

    Ding, Zhao-Wei; Lu, Yong-Ze; Fu, Liang; Ding, Jing; Zeng, Raymond J


    In this study, the coculture system of denitrifying anaerobic methane oxidation (DAMO) microbes and anaerobic ammonium oxidation (anammox) bacteria was successfully enriched in a hollow-fiber membrane biofilm reactor (HfMBR) using freshwater sediment as the inoculum. The maximal removal rates of nitrate and ammonium were 78 mg N/L/day (131 mg N/m(2)/day) and 26 mg N/L/day (43 mg N/m(2)/day), respectively. Due to the high rate of methane mass transfer in HfMBR, the activity of DAMO archaea continued to increase during the enrichment period, indicating that HfMBR could be a powerful tool to enrich DAMO microorganisms. Effects of partial methane pressure, temperature, and pH on the cocultures were obvious. However, the microbial activity in HfMBR could be recovered quickly after the shock change of environmental factors. Furthermore, the result also found that DAMO bacteria likely had a stronger competitive advantage than anammox bacteria under the operating conditions in this study. High-throughput sequencing 16S rRNA genes illustrated that the dominant microbes were NC10, Euryarchaeota, Proteobacteria, Planctomycetes, and Chlorobi with relative abundance of 38.8, 26.2, 13.78, 6.2, and 3.6 %, respectively.

  15. A little bit of light goes a long way: the role of phototrophs on mercury cycling. (United States)

    Grégoire, Daniel S; Poulain, A J


    Among toxic metals, mercury (Hg) is a global priority contaminant due to the biomagnification of the most toxic form methylmercury (MeHg) in food webs, even in remote regions, such as the high Arctic. The importance of Hg as a chemical of major concern to human health was underscored by the recent adoption of the Minamata Convention on Mercury, a legally binding treaty that requires government agencies be equipped to monitor processes affecting global mercury transport and cycling. For several decades now, field and laboratory experiments have shown that phototrophs can directly interact with Hg and affect its speciation and fate. While an important body of work on the role of chemotrophic microbes on Hg cycling has been undertaken, the role of phototrophs is too often overlooked. Strikingly, what is known about phototroph-Hg interactions pertains mostly to oxygenic phototrophs with relatively little being known about anoxygenic phototrophs. Ongoing environmental change will no doubt affect the physical and chemical properties of aquatic ecosystems, which in turn will alter all phototrophic community dynamics. How these changes will affect the Hg cycle represent an important knowledge gap. After synthesizing what is currently known about chemotrophic Hg transformations, we describe the current state of knowledge on what is known about how phototrophs (bacteria and algae) affect Hg cycling (i.e., alteration of Hg redox state, Hg scavenging, potential for methylation) as well as describe the cellular and molecular targets of Hg toxicity in phototrophs. We discuss these interactions in an evolutionary context and provide recommendations for future research directions.

  16. Isolation and identification of bacteria responsible for simultaneous anaerobic ammonium and sulfate removal

    Institute of Scientific and Technical Information of China (English)


    Sulfate-dependent anaerobic ammonium oxidation is a novel biological reaction,in which ammonium is oxidized with sulfate as the electron acceptor under anoxic conditions.Ammonium and sulfate are cosmopolitan chemical species which are an integral part of the global nitrogen and sulfur cycles.A detailed exploration of sulfate-dependent anaerobic ammonium oxidation is quite practical.In this work,a bacterial strain named ASR has been isolated from an anaerobic ammonia and sulfate removing reactor working under steady-state.On the basis of electron microscopy,physiological tests and 16S rDNA phylogenetic sequence analysis,the strain ASR is found to be related to Bacillus benzoevorans.According to the biological carbon source utilization test,the strain ASR could use many carbon sources.Its optimum pH value and temperature were 8.5 and 30 °C,respectively.The test proves that the strain ASR is able to use sulfate to oxidize ammonia anaerobically.The maximum ammonia and sulfate removal rates were 44.4% and 40.0%,respectively.The present study provided biological evidence for the confirmation and development of sulfate-dependent anaerobic ammonium oxidation and brought new insights into the global nitrogen and sulfur cycles.

  17. Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lenly J. Weathers; Lynn E. Katz


    The use of zero valent iron, permeable reactive barriers (PRBs) for groundwater remediation continues to increase. AN exciting variation of this technology involves introducing anaerobic bacteria into these barriers so that both biological and abiotic pollutant removal processes are functional. This work evaluated the hypothesis that a system combining a mixed culture of sulfate reducing bacteria (SRB) with zero valent iron would have a greater cr(VI) removal efficiency and a greater total Cr(VI) removal capacity than a zero valent iron system without the microorganisms. Hence, the overall goal of this research was to compare the performance of these types of systems with regard to their Cr(VI) removal efficiency and total Cr(VI) removal capacity. Both batch and continuous flow reactor systems were evaluated.

  18. [H+-K+-exchange in anaerobically grown Escherichia coli bacteria during use of various sugars as exogenous energy sources]. (United States)

    Trchunian, A A; Ogandzhanian, E S


    E.coli bacteria, grown in anaerobic conditions, in the medium with glucose, lactose or maltose, upon transferring into a fresh medium with the same sugar acidify it and accumulate potassium ions with a fixed stoichiometry for the N,N'-dicyclohexylcarbodiimide-inhibited cation fluxes, which is equal to 2H+ of the cytoplasm per one K+ of the medium. Such an H(+)-K(+)-exchange is sensitive to osmotic shock. In the medium with lactose or maltose cation fluxes are less and the intracellular K+ activity at the moment of maximal accumulation is lower. The H(+)-K(+)-exchange with a variable stoichiometry of cation fluxes is lost in bacteria, grown in a medium with lactose or maltose.

  19. Co-metabolic conversion of toluene in anaerobic n-alkane-degrading bacteria. (United States)

    Rabus, Ralf; Jarling, René; Lahme, Sven; Kühner, Simon; Heider, Johann; Widdel, Friedrich; Wilkes, Heinz


    Diverse microorganisms have been described to degrade petroleum hydrocarbons anaerobically. Strains able to utilize n-alkanes do not grow with aromatic hydrocarbons, whereas strains able to utilize aromatic hydrocarbons do not grow with n-alkanes. To investigate this specificity in more detail, three anaerobic n-alkane degraders (two denitrifying, one sulfate-reducing) and eight anaerobic alkylbenzene degraders (five denitrifying, three sulfate-reducing) were incubated with mixtures of n-alkanes and toluene. Whereas the toluene degradationers formed only the characteristic toluene-derived benzylsuccinate and benzoate, but no n-alkane-derived metabolites, the n-alkane degraders formed toluene-derived benzylsuccinate, 4-phenylbutanoate, phenylacetate and benzoate besides the regular n-alkane-derived (1-methylalkyl)succinates and methyl-branched alkanoates. The co-metabolic conversion of toluene by anaerobic n-alkane degraders to the level of benzoate obviously follows the anaerobic n-alkane degradation pathway with C-skeleton rearrangement and decarboxylation rather than the β-oxidation pathway of anaerobic toluene metabolism. Hence, petroleum-derived aromatic metabolites detectable in anoxic environments may not be exclusively formed by genuine alkylbenzene degraders. In addition, the hitherto largely unexplored fate of fumarate hydrogen during the activation reactions was examined with (2,3-(2) H(2) )fumarate as co-substrate. Deuterium was completely exchanged with hydrogen at the substituted carbon atom (C-2) of the succinate adducts of n-alkanes, whereas it is retained in toluene-derived benzylsuccinate, regardless of the type of enzyme catalysing the fumarate addition reaction.

  20. Anaerobic bacteria in upper respiratory tract and head and neck infections: microbiology and treatment. (United States)

    Brook, Itzhak


    Anaerobes are the predominant components of oropharyngeal mucous membranes bacterial flora, and are therefore a common cause of bacterial infections of endogenous origin of upper respiratory tract and head and neck. This review summarizes the aerobic and anaerobic microbiology and antimicrobials therapy of these infections. These include acute and chronic otitis media, mastoiditis and sinusitis, pharyngo-tonsillitis, peritonsillar, retropharyngeal and parapharyngeal abscesses, suppurative thyroiditis, cervical lymphadenitis, parotitis, siliadenitis, and deep neck infections including Lemierre Syndrome. The recovery from these infections depends on prompt and proper medical and when indicated also surgical management.

  1. Decoloration of textile wastewater by means of a fluidized-bed loop reactor and immobilized anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Georgiou, D. [Department of Environmental Engineering, Demokritos University of Thrace, 67100 Xanthi (Greece)]. E-mail:; Aivasidis, A. [Department of Environmental Engineering, Demokritos University of Thrace, 67100 Xanthi (Greece)


    Textile wastewater was treated by means of a fluidized-bed loop reactor and immobilized anaerobic bacteria. The main target of this treatment was decoloration of the wastewater and transformation of the non-biodegradable azo-reactive dyes to the degradable, under aerobic biological conditions, aromatic amines. Special porous beads (Siran'' (registered)) were utilized as the microbial carriers. Acetic acid solution, enriched with nutrients and trace elements, served both as a pH-regulator and as an external substrate for the growth of methanogenic bacteria. The above technique was firstly applied on synthetic wastewater (an aqueous solution of a mixture of different azo-reactive dyes). Hydraulic residence time was gradually decreased from 24 to 6 h over a period of 3 months. Full decoloration of the wastewater could be achieved even at such a low hydraulic residence time (6 h), while methane-rich biogas was also produced. The same technique was then applied on real textile wastewater with excellent results (full decoloration at a hydraulic residence time of 6 h). Furthermore, the effluent proved to be highly biodegradable by aerobic microbes (activated-sludge). Thus, the above-described anaerobic/aerobic biological technique seems to be a very attractive method for treating textile wastewater since it is cost-effective and environment-friendly.

  2. Respiratory Ammonification of Nitrate Coupled to Anaerobic Oxidation of Elemental Sulfur in Deep-Sea Autotrophic Thermophilic Bacteria (United States)

    Slobodkina, Galina B.; Mardanov, Andrey V.; Ravin, Nikolai V.; Frolova, Anastasia A.; Chernyh, Nikolay A.; Bonch-Osmolovskaya, Elizaveta A.; Slobodkin, Alexander I.


    Respiratory ammonification of nitrate is the microbial process that determines the retention of nitrogen in an ecosystem. To date, sulfur-dependent dissimilatory nitrate reduction to ammonium has been demonstrated only with sulfide as an electron donor. We detected a novel pathway that couples the sulfur and nitrogen cycles. Thermophilic anaerobic bacteria Thermosulfurimonas dismutans and Dissulfuribacter thermophilus, isolated from deep-sea hydrothermal vents, grew autotrophically with elemental sulfur as an electron donor and nitrate as an electron acceptor producing sulfate and ammonium. The genomes of both bacteria contain a gene cluster that encodes a putative nitrate ammonification enzyme system. Nitrate reduction occurs via a Nap-type complex. The reduction of produced nitrite to ammonium does not proceed via the canonical Nrf system because nitrite reductase NrfA is absent in the genomes of both microorganisms. The genome of D. thermophilus encodes a complete sulfate reduction pathway, while the Sox sulfur oxidation system is missing, as shown previously for T. dismutans. Thus, in high-temperature environments, nitrate ammonification with elemental sulfur may represent an unrecognized route of primary biomass production. Moreover, the anaerobic oxidation of sulfur compounds coupled to growth has not previously been demonstrated for the members of Thermodesulfobacteria or Deltaproteobacteria, which were considered exclusively as participants of the reductive branch of the sulfur cycle. PMID:28194142

  3. Anaerobic nitrite-dependent methane-oxidizing bacteria - novel participants in methane cycling of drained peatlands ecosystems (United States)

    Kravchenko, Irina; Sukhacheva, Marina; Menko, Ekaterina; Sirin, Andrey


    Northern peatlands are one of the key sources of atmospheric methane. Process-based studies of methane dynamic are based on the hypothesis of the balance between microbial methane production and oxidation, but this doesn't explain all variations in and constraints on peatland CH4 emissions. One of the reasons for this discrepancy could be anaerobic methane oxidation (AOM) - the process which is still poorly studied and remained controversial. Very little is known about AOM in peatlands, where it could work as an important 'internal' sink for CH4. This lack of knowledge primarily originated from researchers who generally consider AOM quantitatively insignificant or even non-existent in northern peatland ecosystems. But not far ago, Smemo and Yavitt (2007) presented evidence for AOM in freshwater peatlands used indirect techniques including isotope dilution assays and selective methanogenic inhibitors. Nitrite-dependent anaerobic methane oxidation NC10 group bacteria (n-damo) were detected in a minerotrophic peatland in the Netherlands that is infiltrated by nitrate-rich ground water (Zhu et al., 2012). Present study represents the first, to our knowledge, characterization of AOM in human disturbed peatlands, including hydrological elements of artificial drainage network. The experiments were conducted with samples of peat from drained peatlands, as well as of water and bottom sediments of ditches from drained Dubnensky mire massif, Moscow region (Chistotin et al., 2006; Sirin et al., 2012). This is the key testing area of our research group in European part of Russia for the long-term greenhouse gases fluxes measurements supported by testing physicochemical parameters, intensity and genomic diversity of CH4-cycling microbial communities. Only in sediments of drainage ditches the transition anaerobic zone was found, where methane and nitrate occurred, suggested the possible ecological niche for n-damo bacteria. The NC10 group methanotrophs were analyzed by PCR

  4. Enhancement of phototrophic hydrogen production by Rhodobacter sphaeroides ZX-5 using a novel strategy - shaking and extra-light supplementation approach

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xu; Wang, Yong-Hong; Zhang, Si-Liang; Chu, Ju; Zhang, Ming; Huang, Ming-Zhi; Zhuang, Ying-Ping [State Key Laboratory of Bioreactor Engineering, P.O. Box 329, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)


    Biohydrogen has gained attention due to its potential as a sustainable alternative to conventional methods for hydrogen production. In this study, the effect of light intensity as well as cultivation method (standing- and shaking-culture) on the cell growth and hydrogen production of Rhodobacter sphaeroides ZX-5 were investigated in 38-ml anaerobic photobioreactor with RCVBN medium. Thus, a novel shaking and extra-light supplementation (SELS) approach was developed to enhance the phototrophic H{sub 2} production by R. sphaeroides ZX-5 using malate as the sole carbon source. The optimum illumination condition for shaking-culture by strain ZX-5 increased to 7000-8000 lux, markedly higher than that for standing-culture (4000-5000 lux). Under shaking and elevated illumination (7000-8000 lux), the culture was effective in promoting photo-H{sub 2} production, resulting in a 59% and 56% increase of the maximum and average hydrogen production rate, respectively, in comparison with the culture under standing and 4000-5000 lux conditions. The highest hydrogen-producing rate of 165.9 ml H{sub 2}/l h was observed under the application of SELS approach. To our knowledge, this record is currently the highest hydrogen production rate of non-immobilized purple non-sulphur (PNS) bacteria. This optimal performance of photo-H{sub 2} production using SELS approach is a favorable choice of sustainable and economically feasible strategy to improve phototrophic H{sub 2} production efficiency. (author)

  5. Detection, phylogeny and population dynamics of syntrophic propionate-oxidizing bacteria in anaerobic granular sludge.

    NARCIS (Netherlands)

    Harmsen, H.J.M.


    The research described this thesis concerns the diversity and phylogeny of syntrophic propionate-oxidizing bacteria and their ecology in granular sludge, from which they were obtained. 16S rRNA was used as a molecular marker to study both the phylogeny and the ecology of these bacteria. Sequence ana

  6. Bioaugmentation of anaerobic sludge digestion with iron-reducing bacteria: process and microbial responses to variations in hydraulic retention time. (United States)

    Baek, Gahyun; Kim, Jaai; Shin, Seung Gu; Lee, Changsoo


    Although anaerobic digestion (AD) is a widely used option to manage waste activated sludge (WAS), there are some drawbacks related to its slow reaction rate and low energy productivity. This study examined an anaerobic WAS digester, augmented with an iron-reducing microbial consortium, relative to changes in microbial community structure and process performance at decreasing hydraulic retention times (HRTs) of 20 to 10 days. The enhanced methanation performance (approximately 40 % increase in methane yield) by the bioaugmentation was sustained until the HRT was decreased to 12.5 days, under Fe(3+)-rich conditions (ferric oxyhydroxide, 20 mM Fe). Enhanced iron-reducing activity was evidenced by the increased Fe(2+) to total Fe ratio maintained above 50 % during the stable operational phases. A further decrease in HRT to 10 days resulted in a significant performance deterioration, along with a drop in the Fe(2+) to total Fe ratio to <35 %, after four turnovers of operation. Prevailing existence of putative iron-reducing bacteria (IRBs) was identified by denaturing gradient gel electrophoresis (DGGE), with Spirochaetaceae- and Thauera-related organisms being dominant members, and clear dominance shifts among them with respect to decrease in HRT were observed. Lowering HRT led to evident shifts in bacterial community structure likely associated with washout of IRBs, leading to decreases in iron respiration activity and AD performance at a lower HRT. The bacterial community structure shifted dynamically over phases, and the community transitions correlated well with the changes in process performance. Overall, the combined biostimulation and bioaugmentation investigated in this study proved effective for enhanced methane recovery from anaerobic WAS digestion, which suggests an interesting potential for high-rate AD.

  7. Air-dust-borne associations of phototrophic and hydrocarbon-utilizing microorganisms: promising consortia in volatile hydrocarbon bioremediation. (United States)

    Al-Bader, Dhia; Eliyas, Mohamed; Rayan, Rihab; Radwan, Samir


    Aquatic and terrestrial associations of phototrophic and heterotrophic microorganisms active in hydrocarbon bioremediation have been described earlier. The question arises: do similar consortia also occur in the atmosphere? Dust samples at the height of 15 m were collected from Kuwait City air, and analyzed microbiologically for phototrophic and heterotrophic hydrocarbon-utilizing microorganisms, which were subsequently characterized according to their 16S rRNA gene sequences. The hydrocarbon utilization potential of the heterotrophs alone, and in association with the phototrophic partners, was measured quantitatively. The chlorophyte Gloeotila sp. and the two cyanobacteria Nostoc commune and Leptolyngbya thermalis were found associated with dust, and (for comparison) the cynobacteria Leptolyngbya sp. and Acaryochloris sp. were isolated from coastal water. All phototrophic cultures harbored oil vapor-utilizing bacteria in the magnitude of 10(5) g(-1). Each phototrophic culture had its unique oil-utilizing bacteria; however, the bacterial composition in Leptolyngbya cultures from air and water was similar. The hydrocarbon-utilizing bacteria were affiliated with Acinetobacter sp., Aeromonas caviae, Alcanivorax jadensis, Bacillus asahii, Bacillus pumilus, Marinobacter aquaeolei, Paenibacillus sp., and Stenotrophomonas maltophilia. The nonaxenic cultures, when used as inocula in batch cultures, attenuated crude oil in light and dark, and in the presence of antibiotics and absence of nitrogenous compounds. Aqueous and diethyl ether extracts from the phototrophic cultures enhanced the growth of the pertinent oil-utilizing bacteria in batch cultures, with oil vapor as a sole carbon source. It was concluded that the airborne microbial associations may be effective in bioremediating atmospheric hydrocarbon pollutants in situ. Like the aquatic and terrestrial habitats, the atmosphere contains dust-borne associations of phototrophic and heterotrophic hydrocarbon

  8. The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions (United States)

    Gorbacheva, M.


    M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for

  9. Pretreatment of wheat straw and conversion of xylose and xylan to ethanol by thermophilic anaerobic bacteria

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Jensen, K.; Nielsen, P.


    Wheat straw was pretreated by wet oxidation (oxygen pressure, alkaline conditions, elevated temperature) or hydrothermal processing (without oxygen) in order to solubilize the hemicellulose, facilitating bio-conversion. The effect of oxygen pressure and sodium carbonate addition on hemicellulose...... solubilization was investigated. The two process parameters had little effect on the solubilization of hemicellulose. However alkaline conditions affected the furfural formation whereas oxygen had no effect. After pretreatment, the filtrate was used as a fermentation medium for thermophilic anaerobic bacterin...... of the microorganism to the wet oxidized filtrate was also examined. Copyright (C) 1997 Elsevier Science Ltd....

  10. Divergent mitochondrial respiratory chains in phototrophic relatives of apicomplexan parasites

    KAUST Repository

    Flegontov, Pavel


    Four respiratory complexes and ATP-synthase represent central functional units in mitochondria. In some mitochondria and derived anaerobic organelles, a few or all of these respiratory complexes have been lost during evolution. We show that the respiratory chain of Chromera velia, a phototrophic relative of parasitic apicomplexans, lacks complexes I and III, making it a uniquely reduced aerobic mitochondrion. In Chromera, putative lactate:cytochrome c oxidoreductases are predicted to transfer electrons from lactate to cytochrome c, rendering complex III unnecessary. The mitochondrial genome of Chromera has the smallest known protein-coding capacity of all mitochondria, encoding just cox1 and cox3 on heterogeneous linear molecules. In contrast, another photosynthetic relative of apicomplexans, Vitrella brassicaformis, retains the same set of genes as apicomplexans and dinoflagellates (cox1, cox3, and cob). © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  11. Potential for using thermophilic anaerobic bacteria for bioethanol production from hemicellulose

    DEFF Research Database (Denmark)

    Sommer, P.; Georgieva, Tania I.; Ahring, Birgitte Kiær


    A limited number of bacteria, yeast and fungi can convert hemicellulose or its monomers (xylose, arabinose, mannose and galactose) into ethanol with a satisfactory yield and productivity. In the present study we tested a number of thermophilic enrichment cultures, and new isolates of thermophilic...

  12. Characterization of lighted upflow anaerobic sludge blanket (LUASB) method under sulfate-rich conditions. (United States)

    Sawayama, S; Tsukahara, K; Yagishita, T; Hanada, S


    Growth of phototrophic bacteria was induced from granules in a lighted upflow anaerobic sludge blanket (LUASB) reactor supplied with an organic-acid-based medium containing 141.7 mg S.l(-1) of SO4(2-) under light conditions (100 microE.m(-2).s(-1)). We investigated the population dynamics of phototrophic bacteria in the LUASB reactor and the performance of the LUASB reactor for wastewater treatment and poly-beta-hydroxybutyrate (PHB) production under anaerobic light and sulfate-rich conditions. In vivo absorption spectra and a colony count suggested that populations of Rhodopseudomonas palustris and Blastochloris sulfoviridis in the LUASB reactor supplied with a medium containing 574.4 mg S.l(-1) of SO4(2-) under light conditions were lower than those supplied with a medium containing 1.0 or 141.7 mg S.l(-1) of SO4(2-) under parallel conditions. Removal efficiencies of ammonium and phosphate in the LUASB reactor supplied with the medium containing 141.7 mg S.l(-1) of SO4(2-) under light conditions were higher than those under parallel conditions but without illumination. The difference in the results of runs under light or dark conditions suggested that the ammonium and phosphate ion removal efficiencies were improved by increasing the amount of phototrophic bacterial biomass in the LUASB reactor under sulfate-rich conditions. The average PHB production rates of the bacterial cells recovered from the effluent of the LUASB reactor supplied with a medium containing 141.7, 283.5 or 574.4 mg S.l(-1) of SO4(2-) were 1.0-2.9 mg.l(-1)-reactor.d(-1) and the average PHB content based on the dry bacterial biomass was 1.4-3.6%.

  13. [Effect of temperature on H+-K+ exchange in Escherichia coli bacteria during their anaerobic growth]. (United States)

    Vardanian, V; Trchunian, A


    The H(+)-K(+)-exchange in E.coli grown under anaerobic conditions at temperatures from 17 to 37 degrees C was studied. The Arrhenius plots for both the N,N'-dicyclohexylcarbodiimide-sensitive release of H+ and K+ uptake by cells transferred into a fresh medium containing a carbon source (glucose) are nonlinear. The activation energy values for the transport of these cations at different temperatures significantly differ. It is shown that as the temperature decreases, the accumulation of K+ by cells is reduced. In this process, the initial rate of K+ absorption through the TrkA system, the time of accumulation of these cations by cells and the osmosensitivity of K+ uptake substantially decrease. At temperatures below 20 degrees C, the absorption becomes insensitive to the secondary osmoshock. However, the stoichiometry of N,N'-dicyclohexylcar-bodiimide-sensitive cation fluxes remains unchanged and is equal to 2H+:K+. It is assumed that the H(+)-K(+)-exchange proceeds by the operation of an ensemble of oligomers, formed from the protomers of F0F1 and TrkA, which rearrange by the action of temperature, whereas F0F1 and TrkA in each protomer do not change.

  14. Studies on some characteristics of hydrogen production by cell-free extracts of rumen anaerobic bacteria. (United States)

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


    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.

  15. Direct observation and quantification of extracellular long-range electron flow in anaerobic bacteria (United States)

    Malvankar, Nikhil; Yalcin, Sibel; Vargas, Madeline; Tuominen, Mark; Lovley, Derek


    Some anaerobic microorganisms are capable of transporting electrons outside their cell to distant electron acceptors such as metals, minerals or partner species. Previous studies have focused primarily on transport over short distances ( 10 μm) using pili filaments that show organic metal-like conductivity. Pili also enable direct exchange of electrons among syntrophic Geobacter co-cultures. In order to establish the physical principles underlying this remarkable electron transport, we have employed a novel scanning probe microscopy-based method to perform quantitative measurements of electron flow at a single cell level under physiological conditions. Using this nanoscopic approach, we have directly observed the propagation and distribution of injected electrons in individual native bacterial extracellular proteins. Our direct measurements demonstrate unambiguously for the first time that the pili of G. sulfurreducens are a novel class of electronically functional proteins that can sustain electron flow in a surprising manner that has not been observed previously in any other natural protein. Funded by Office of Naval Research, DOE Genomic Sciences and NSF-NSEC Center for Hierarchical Manufacturing grant no. CMMI-1025020.

  16. Comprehensive analysis of aerobic and anaerobic bacteria found on dental bib clips. (United States)

    Alt-Holland, Addy; Murphy, Christina M; Powers, Anne; Kublin, Claire L; Jeong, Youjin Natalie; DiMattia, Michelle; Pham, Linh; Park, Angel; Finkelman, Matthew; Lombard, Maureen; Hanley, James B; Paster, Bruce J; Kugel, Gerard


    Multiple-use dental bib clips are considered to present relatively low risks for transmitting infections and, thus, are thought to only require disinfection between patient visits. This study was designed to: 1) determine the presence and composition of bacterial contaminants on reusable rubber-faced metal bib clips after dental treatment at the hygiene clinic at Tufts University School of Dental Medicine and 2) evaluate the effectiveness of the disinfection for this clip type. Aerobic and anaerobic bacterial contaminant loads on the surfaces of the clips were investigated immediately after hygiene treatments were rendered and again after clips were disinfected. The species and strains of bacterial isolates were identified using 16S rDNA sequencing and Human Oral Microbe Identification Microarray analyses. The results demonstrated that although the use of disinfection proved to be significantly effective, some clips retained at least one bacterium on their surfaces after disinfection. Although the bacterial species present on disinfected clips were typical skin or environmental isolates, some were oral in origin. In the study's settings, bacterial presence on the clips did not indicate an infectious disease problem. The different bacterial loads on clips suggest that cross-contamination risks may not be the same for all clinics, and that this difference may be related to the type of treatments and services performed.

  17. Kinetic analysis of hydrogen production using anaerobic bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Xiaohua; Yang, Haijun; Yuan, Zhuliang; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190 (China)


    The micellar formation and entrapment of bacteria cell in reverse micelles were investigated by ultraviolet spectrum (UV), fluorescence spectrum, and scanning electron microscope (SEM). The hydrogen production in reverse micelles was confirmed. The Gompertz equation was employed to evaluate the hydrogen-producing behavior in reverse micellar systems. Different systems including dioctyl sulfosuccinate sodium salt (AOT)-isooctane, sodium dodecyl sulfate (SDS)-benzene and SDS-carbon tetrachloride (CCl{sub 4}) reverse micelles were analysized. The results revealed that the maximum rate of hydrogen production (R{sub m}) was also suitable to formulate the relationship between hydrogen-producing rate and hydrogen productivity in reverse micelles. (author)

  18. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion

    Directory of Open Access Journals (Sweden)

    Christopher Neil Lyles


    Full Text Available The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11 or a methanogen (M. hungatei. The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  19. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion. (United States)

    Lyles, Christopher N; Le, Huynh M; Beasley, William Howard; McInerney, Michael J; Suflita, Joseph M


    The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11) or a methanogen (M. hungatei). The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  20. Vertical profiles of community abundance and diversity of anaerobic methanotrophic archaea (ANME) and bacteria in a simple waste landfill in north China. (United States)

    Dong, Jun; Ding, Linjie; Wang, Xu; Chi, Zifang; Lei, Jiansen


    Anaerobic methane oxidation (AMO) is considered to be an important sink of CH4 in habitats as marine sediments. But, few studies focused on AMO in landfills which may be an important sink of CH4 derived from waste fermentation. To show evidence of AMO and to uncover function anaerobic methanotroph (ANME) community in landfill, different age waste samples were collected in Jinqianpu landfill located in north China. Through high-throughput sequencing, Methanomicrobiales and Methanosarcinales archaea associated with ANME and reverse methanogenic archaea of Methanosarcina and Methanobacterium were detected. Sulfate-reducing bacteria (SRB) (Desulfobulbus and Desulfococcus) which could couple with ANME-conducting AMO were also found. But, the community structure of ANME had no significant difference with depths. From the results of investigation, we can come to a conclusion that sulfate-dependent anaerobic methane oxidation (SR-DAMO) would be the dominant AMO process in the landfill, while iron-dependent anaerobic methane oxidation (M/IR-DAMO) process was weak though concentration of ferric iron was large in the landfill. Denitrification-dependent anaerobic methane oxidation (NR-DAMO) was negative because of lack of nitrate and relevant function microorganisms in the landfill. Results also indicate that CH4 mitigation would have higher potential by increasing electron acceptor contents and promoting the growth of relevant function microorganisms.

  1. Shifts in the community structure and activity of anaerobic ammonium oxidation bacteria along an estuarine salinity gradient (United States)

    Zheng, Yanling; Jiang, Xiaofen; Hou, Lijun; Liu, Min; Lin, Xianbiao; Gao, Juan; Li, Xiaofei; Yin, Guoyu; Yu, Chendi; Wang, Rong


    Anaerobic ammonium oxidation (anammox) is a major microbial pathway for nitrogen (N) removal in estuarine and coastal environments. However, understanding of anammox bacterial dynamics and associations with anammox activity remains scarce along estuarine salinity gradient. In this study, the diversity, abundance, and activity of anammox bacteria, and their potential contributions to total N2 production in the sediments along the salinity gradient (0.1-33.8) of the Yangtze estuarine and coastal zone, were studied using 16S rRNA gene clone library, quantitative polymerase chain reaction assay, and isotope-tracing technique. Phylogenetic analysis showed a significant change in anammox bacterial community structure along the salinity gradient (P important factor in controlling the relative role of anammox to total N2 production in the Yangtze estuarine and coastal zone. Overall, our data demonstrated a biogeographical distribution of anammox bacterial diversity, abundance, and activity along the estuarine salinity gradient and suggested that salinity is a major environmental control on anammox process in the estuarine and coastal ecosystems.

  2. Anaerobic thermophilic bacteria isolated from a Venezuelan oil field and its potential use in microbial improved oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Trebbau, G.; Fernandez, B.; Marin, A. [INTEVEP S.A., Caracas (Venezuela)


    The objective of this work is to determine the ability of indigenous bacteria from a Venezuelan oil field to grow under reservoir conditions inside a porous media, and to produce metabolites capable of recovering residual crude oil. For this purpose, samples of formation waters from a central-eastern Venezuelan oil reservoir were enriched with different carbon sources and a mineral basal media. Formation water was used as a source of trace metals. The enrichments obtained were incubated at reservoir temperature (71{degrees}C), reservoir pressure (1,200 psi), and under anaerobic conditions for both outside and inside porous media (Berea core). Growth and metabolic activity was followed outside porous media by measuring absorbance at 660 nm, increases in pressure, and decreases in pH. Inside porous media bacterial activity was determined by visual examination of the produced waters (gas bubbles and bacterial cells). All the carbohydrates tested outside porous media showed good growth at reservoir conditions. The pH was lowered, gases such as CO{sub 2} and CH{sub 4} were identified by GC. Surface tension was lowered in some enrichments by 30% when compared to controls. Growth was decreased inside porous media, but gases were produced and helped displace oil. In addition, 10% residual oil was recovered from the Berea core. Mathematical modeling was applied to the laboratory coreflood experiment to evaluate the reproducibility of the results obtained.

  3. Laboratory identification of anaerobic bacteria isolated on Clostridium difficile selective medium. (United States)

    Rodriguez, Cristina; Warszawski, Nathalie; Korsak, Nicolas; Taminiau, Bernard; Van Broeck, Johan; Delmée, Michel; Daube, Georges


    Despite increasing interest in the bacterium, the methodology for Clostridium difficile recovery has not yet been standardized. Cycloserine-cefoxitin fructose taurocholate (CCFT) has historically been the most used medium for C. difficile isolation from human, animal, environmental, and food samples, and presumptive identification is usually based on colony morphologies. However, CCFT is not totally selective. This study describes the recovery of 24 bacteria species belonging to 10 different genera other than C. difficile, present in the environment and foods of a retirement establishment that were not inhibited in the C. difficile selective medium. These findings provide insight for further environmental and food studies as well as for the isolation of C. difficile on supplemented CCFT.

  4. Dissimilatory Reduction of Elemental Selenium to Selenide in Sediments and Anaerobic Cultures of Selenium Respiring Bacteria (United States)

    Herbel, M. J.; Switzer-Blum, J.; Oremland, R. S.


    Selenium contaminated environments often contain elemental Se (Se0) in their sediments that originates from dissimilatory reduction of Se oxyanions. The forms of Se in sedimentary rocks similarly contain high proportions of Se0, but much of the Se is also in the form of metal selenides, Se-2. It is not clear if the occurrence of these selenides is due to microbial reduction of Se0, or some other biological or chemical process. In this investigation we examined the possibility that bacterial respiratory reduction of Se0 to Se-2 could explain the presence of the latter species in sedimentary rocks. We conducted incubations of anoxic sediment slurries amended with different forms of Se0. High levels of Se0 (mM) were added to San Francisco Bay sediments in order to enhance the detection of soluble HSe-, which was precipitated with Cu2+ then redissolved and quantified by ICP-MS. Concentrations of HSe- were highest in live samples amended with red amorphous Se0 formed by either microbial reduction of Se+4 ("biogenic Se0") or by chemical oxidation of H2Se(g) ("chem. Se0"); very little HSe- was formed in those amended with black crystalline Se0, indicating the general lack of reactivity of this allotrope. Controls poisoned with 10% formalin did not produce HSe- from additions of chem. Se0. Reduction of both forms of red amorphous Se0 to HSe- occurred vigorously in growing cultures of Bacillus selenitireducens, an anaerobic halophile previously isolated from sediments of Mono Lake, CA. Up to 73% and 68% of red amorphous, biogenic Se0 or chem. Se0, respectively, was reduced to HSe- during growth of B. selenitireducens, (incubation time ~ 200 hrs): oxidation of lactate to acetate as well as cell density increases indicated that a dissimilatory reduction pathway was likely. Reduction was most enhanced when cells were previously grown on elemental sulfur or Se+4. In contrast to the growth experiments, washed cell suspensions of B. selenitireducens exhibited no HSe- production

  5. Phototrophic Fe(II)-oxidation in the chemocline of a ferruginous meromictic lake (United States)

    Walter, Xavier A.; Picazo, Antonio; Miracle, Maria R.; Vicente, Eduardo; Camacho, Antonio; Aragno, Michel; Zopfi, Jakob


    Precambrian Banded Iron Formation (BIF) deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II)) with photosynthetically produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II) has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II) in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was lacking. Here we show that anoxygenic phototrophic bacteria contribute to Fe(II) oxidation in the water column of the ferruginous sulfate-poor, meromictic lake La Cruz (Spain). We observed in-situ photoferrotrophic activity through stimulation of phototrophic carbon uptake in the presence of Fe(II), and determined light-dependent Fe(II)-oxidation by the natural chemocline microbiota. Moreover, a photoferrotrophic bacterium most closely related to Chlorobium ferrooxidans was enriched from the ferruginous water column. Our study for the first time demonstrates a direct link between anoxygenic photoferrotrophy and the anoxic precipitation of Fe(III)-oxides in a ferruginous water column, providing a plausible mechanism for the bacterial origin of BIFs before the advent of free oxygen. However, photoferrotrophs represent only a minor fraction of the anoxygenic phototrophic community with the majority apparently thriving by sulfur cycling, despite the very low sulfur content in the ferruginous chemocline of Lake La Cruz. PMID:25538702

  6. Anaerobic degradation of cyclohexane by sulfate-reducing bacteria from hydrocarbon-contaminated marine sediments

    Directory of Open Access Journals (Sweden)

    Ulrike eJaekel


    Full Text Available The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sediments. Microscopic analyses showed an apparent dominance by oval cells of 1.5×0.8 m. Analysis of a 16S rRNA gene library, followed by whole-cell hybridization with group- and sequence-specific oligonucleotide probes showed that these cells belonged to a single phylotype, and were accounting for more than 80% of the total cell number. The dominant phylotype, affiliated with the Desulfosarcina-Desulfococcus cluster of the Deltaproteobacteria, is proposed to be responsible for the degradation of cyclohexane. Quantitative growth experiments showed that cyclohexane degradation was coupled with the stoichiometric reduction of sulfate to sulfide. Substrate response tests corroborated with hybridization with a sequence-specific oligonucleotide probe suggested that the dominant phylotype apparently was able to degrade other cyclic and n-alkanes, including the gaseous alkanes propane and n-butane. Based on GC-MS analyses of culture extracts cyclohexylsuccinate was identified as a metabolite, indicating an activation of cyclohexane by addition to fumarate. Other metabolites detected were 3-cyclohexylpropionate and cyclohexanecarboxylate providing evidence that the overall degradation pathway of cyclohexane under anoxic conditions is analogous to that of n-alkanes.

  7. Physiology and Mechanism of Phototrophic Fe(II) Oxidation by Rhodopseudomonas palustris TIE-1 (United States)

    Jiao, Y.; Newman, D.


    Phototrophic Fe(II)-oxidizing bacteria use electrons from ferrous iron [Fe(II)] and energy from light to drive reductive CO2 fixation. This metabolism is thought to be ancient in origin, and plays an important role in environmental iron cycling. It has been implicated in the deposition of Banded Iron Formations, a class of ancient sedimentary iron deposits. Consistent with this hypothesis, we discovered that hydrogen gas, a thermodynamically favorable electron donor to Fe(II), in an Archean atmosphere would not have inhibited phototrophic Fe(II) oxidation. To understand this physiology and the connection to BIF formation at the molecular level, the mechanisms of phototrophic Fe(II) oxidation were examined in a model organism Rhodopseudomonas palustris TIE-1. Increased expression of a putative decaheme c-type cytochrome, encoded by pioA, was observed when cells were grown under Fe(II)-oxidizing conditions. Two genes located immediately downstream of pioA in the same operon, pioB and pioC, encode a putative outer membrane beta-barrel protein and a putative high potential iron-sulfur protein, respectively. Deletion studies demonstrated that all three genes are involved in phototrophic Fe(II) oxidation. This study provides our first insight into the molecular mechanisms of this metabolism, which will be further characterized by in vitro biochemical studies.

  8. Ethanol and hydrogen production by two thermophilic, anaerobic bacteria isolated from Icelandic geothermal areas. (United States)

    Koskinen, Perttu E P; Beck, Steinar R; Orlygsson, Jóhann; Puhakka, Jaakko A


    Microbial fermentations are potential producers of sustainable energy carriers. In this study, ethanol and hydrogen production was studied by two thermophilic bacteria (strain AK15 and AK17) isolated from geothermal springs in Iceland. Strain AK15 was affiliated with Clostridium uzonii (98.8%), while AK17 was affiliated with Thermoanaerobacterium aciditolerans (99.2%) based on the 16S rRNA gene sequence analysis. Both strains fermented a wide variety of sugar residues typically found in lignocellulosic materials, and some polysaccharides. In the batch cultivations, strain AK17 produced ethanol from glucose and xylose fermentations of up to 1.6 mol-EtOH/mol-glucose (80% of the theoretical maximum) and 1.1 mol-EtOH/mol-xylose (66%), respectively. The hydrogen yields by AK17 were up to 1.2 mol-H2/ mol-glucose (30% of the theoretical maximum) and 1.0 mol-H2/mol-xylose (30%). The strain AK15 produced hydrogen as the main fermentation product from glucose (up to 1.9 mol-H2/mol-glucose [48%]) and xylose (1.1 mol-H2/mol-xylose [33%]). The strain AK17 tolerated exogenously added ethanol up to 4% (v/v). The ethanol and hydrogen production performance from glucose by a co-culture of the strains AK15 and AK17 was studied in a continuous-flow bioreactor at 60 degrees C. Stable and continuous ethanol and hydrogen co-production was achieved with ethanol yield of 1.35 mol-EtOH/mol-glucose, and with the hydrogen production rate of 6.1 mmol/h/L (H2 yield of 0.80 mol-H2/mol-glucose). PCR-DGGE analysis revealed that the AK17 became the dominant bacterium in the bioreactor. In conclusion, strain AK17 is a promising strain for the co-production of ethanol and hydrogen with a wide substrate utilization spectrum, relatively high ethanol tolerance, and ethanol yields among the highest reported for thermoanaerobes.

  9. Genomic analysis reveals key aspects of prokaryotic symbiosis in the phototrophic consortium "Chlorochromatium aggregatum"

    DEFF Research Database (Denmark)

    Liu, Zhenfeng; Müller, Johannes; Li, Tao;


    'Chlorochromatium aggregatum' is a phototrophic consortium, a symbiosis that may represent the highest degree of mutual interdependence between two unrelated bacteria not associated with a eukaryotic host. 'Chlorochromatium aggregatum' is a motile, barrel-shaped aggregate formed from a single cell...... of "Candidatus Symbiobacter mobilis," a polarly flagellated, non-pigmented, heterotrophic bacterium, which is surrounded by approximately 15 epibiont cells of Chlorobium chlorochromatii, a non-motile photolithoautotrophic green sulfur bacterium....

  10. Thermotoga profunda sp. nov. and Thermotoga caldifontis sp. nov., anaerobic thermophilic bacteria isolated from terrestrial hot springs. (United States)

    Mori, Koji; Yamazoe, Atsushi; Hosoyama, Akira; Ohji, Shoko; Fujita, Nobuyuki; Ishibashi, Jun-ichiro; Kimura, Hiroyuki; Suzuki, Ken-ichiro


    Two thermophilic, strictly anaerobic, Gram-negative bacteria, designated strains AZM34c06(T) and AZM44c09(T), were isolated from terrestrial hot springs in Japan. The optimum growth conditions for strain AZM34c06(T) were 60 °C, pH 7.4 and 0% additional NaCl, and those for strain AZM44c09(T) were 70 °C, pH 7.4 and 0% additional NaCl. Complete genome sequencing was performed for both strains, revealing genome sizes of 2.19 Mbp (AZM34c06(T)) and 2.01 Mbp (AZM44c09(T)). Phylogenetic analyses based on 16S rRNA gene sequences and the concatenated predicted amino acid sequences of 33 ribosomal proteins showed that both strains belonged to the genus Thermotoga. The closest relatives of strains AZM34c06(T) and AZM44c09(T) were the type strains of Thermotoga lettingae (96.0% similarity based on the 16S rRNA gene and 84.1% similarity based on ribosomal proteins) and Thermotoga hypogea (98.6 and 92.7% similarity), respectively. Using blast, the average nucleotide identity was 70.4-70.5% when comparing strain AZM34c06(T) and T. lettingae TMO(T) and 76.6% when comparing strain AZM44c09(T) and T. hypogea NBRC 106472(T). Both values are far below the 95% threshold value for species delineation. In view of these data, we propose the inclusion of the two isolates in the genus Thermotoga within two novel species, Thermotoga profunda sp. nov. (type strain AZM34c06(T) = NBRC 106115(T) = DSM 23275(T)) and Thermotoga caldifontis sp. nov. (type strain AZM44c09(T) = NBRC 106116(T) = DSM 23272(T)).

  11. Characterization of specific membrane fatty acids as chemotaxonomic markers for sulfate-reducing bacteria involved in anaerobic oxidation of methane

    DEFF Research Database (Denmark)

    Elvert, M.; Boetius, A.; Knittel, K.;


    Membrane fatty acids were extracted from a sediment core above marine gas hydrates at Hydrate Ridge, NE Pacific. Anaerobic sediments from this environment are characterized by high sulfate reduction rates driven by the anaerobic oxidation of methane (AOM). The assimilation of methane carbon into ...

  12. Application of real-time PCR to determination of combined effect of antibiotics on Bacteria, Methanogenic Archaea, Archaea in anaerobic sequencing batch reactors. (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan


    This study evaluated the long-term effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotic combinations on the microbial community and examined the ways in which these antimicrobials impact the performance of anaerobic reactors. Quantitative real-time PCR was used to determine the effect that different antibiotic combinations had on the total and active Bacteria, Archae and Methanogenic Archae. Three primer sets that targeted metabolic genes encoding formylterahydrofolate synthetase, methyl-coenzyme M reductase and acetyl-coA synthetase were also used to determine the inhibition level on the mRNA expression of the homoacetogens, methanogens and specifically acetoclastic methanogens, respectively. These microorganisms play a vital role in the anaerobic degradation of organic waste and targeting these gene expressions offers operators or someone at a treatment plant the potential to control and the improve the anaerobic system. The results of the investigation revealed that acetogens have a competitive advantage over Archaea in the presence of ETS and ST combinations. Although the efficiency with which methane production takes place and the quantification of microbial populations in both the ETS and ST reactors decreased as antibiotic concentrations increased, the ETS batch reactor performed better than the ST batch reactor. According to the expression of genes results, the syntrophic interaction of acetogens and methanogens is critical to the performance of the ETS and ST reactors. Failure to maintain the stability of these microorganisms resulted in a decrease in the performance and stability of the anaerobic reactors.

  13. A comparative evaluation of antibacterial effectiveness of sodium hypochlorite, Curcuma longa, and Camellia sinensis as irrigating solutions on isolated anaerobic bacteria from infected primary teeth

    Directory of Open Access Journals (Sweden)

    Neha Shashikant Dhariwal


    Full Text Available Context: In endodontics, most of the commercial intra-canal medicaments have cytotoxic reactions and because of their inability to eliminate bacteria from dentinal tubules, recent medicine has turned its attention to the usage of biologic medication prepared from natural plants. The literature to testify the efficacy of natural alternatives in primary teeth is meagre and its effects as irrigating solutions need to be evaluated. Aim: To evaluate the antibacterial effectiveness of sodium hypochlorite, ethanolic extracts of Curcuma longa (turmeric and Camellia sinensis (green tea as irrigating solutions against the anaerobic bacteria isolated from the root canals of infected primary teeth. Materials and Methods: Thirty patients were selected based on the selected inclusion and exclusion criteria. Preoperative radiographs were taken. Rubber dam isolation and working length estimation were done, following which thirty samples were taken from the root canals of infected primary teeth using sterile absorbent paper points and transferred to tubes containing thioglycolate transport medium. The bacteria were then isolated using standard microbiological protocols and were subjected to antibiotic sensitivity testing using the three test irrigants. Statistical Analysis: SPSS 18 software using Chi-square test was used for statistical analysis. Results: The most commonly isolated bacteria included Porphyromonas sp., Bacteroides fragilis, Peptostreptococcus, and Staphylococcus aureus. Sodium hypochlorite and C. longa (turmeric showed good antibacterial effect and were effective against most of the isolated bacteria. There was statistically significant difference in the antibacterial effect among the three tested groups (P < 0.001. The least effective was C. sinensis (green tea. Conclusion: The infected primary teeth almost always present with a polymicrobial structure with a wide variety of anaerobic bacteria. The chemo-mechanical preparation plays an important

  14. Remotely Detectable Biosignatures of Anoxygenic Phototrophs (United States)

    Parenteau, M. N.; Kiang, N. Y.; Blankenship, R. E.; Sanromá, E.; Palle Bago, E.; Hoehler, T. M.; Pierson, B. K.


    Many astrobiological/exobiological studies have been directed at searching for evidence of life on planetary bodies within our solar system, but the search for life does not have to be restricted to our stellar neighborhood. The field of exoplanet research has grown rapidly over the last several years. Studies have moved beyond detection to assessing the habitability and biosignatures of these worlds. The biosignatures considered thus far focus on biogenic gases and planetary surface features, such as the light reflected from the surface of plants to generate the "red edge" of vegetation. Much work has focused on detecting biosignatures of higher life forms (vegetation) on exoplanets. However, land plants only appeared on the Earth 450 million years ago, and required a long path of photosynthetic evolution. There is a dearth of studies examining how light might interact with much simpler, more evolutionarily ancient pigmented communities, such as photosynthetic microbes. These anoxygenic phototrophs, which have inhabited Earth for nearly 80% of its history, may dominate exoplanets at a similar stage of evolution as the Archean or Paleoproterozoic Earth. Similar to the remotely detectable "red edge" of chlorophyll a - containing vegetation, we measured the reflectance spectra of pure cultures and environmental samples of purple sulfur, purple non-sulfur, heliobacteria, green sulfur, and green non-sulfur anoxygenic phototrophs. We observed an increase in reflectivity just past the absorption maximum for the bacteriochlorophyll pigments. Since this reflectance feature is shifted into the NIR compared to that of the red edge of vegetation, we're calling this the "NIR edge" of anoxygenic phototrophs. The bacteriochlorophyll pigments are particularly well suited to absorb the far-red and near-infrared radiation emitted by M dwarf stars, the most common type of star in our galaxy. Therefore these phototrophs serve as model organisms for photosynthesis adapted to

  15. Applications of aerobic and anaerobic bacteria in the fields of biological degradation of contaminants and biological wastewater treatment


    Jovcic, Alexander


    In the work here presented four distinctly different problems were investigated. The first problem was an investigation into the degradation of Dichloroethylene (DCE) and 1,1-bis (p-Chlorophenyl)-2-dichloroethylene (DDE) utilising pure bacterial cultures. The second investigation dealt with the degradation of DDE and polychlorinated Biphenyl’s (PCB’s) utilising anaerobic sediments and soils from New Zealand. The third investigation worked on the Granulation of anaerobic River-sediments in Upf...

  16. In vitro efficacy of cefovecin against anaerobic bacteria isolated from subgingival plaque of dogs and cats with periodontal disease. (United States)

    Khazandi, Manouchehr; Bird, Philip S; Owens, Jane; Wilson, Gary; Meyer, James N; Trott, Darren J


    Periodontal disease is a common disease of dogs and cats often requiring antimicrobial treatment as an adjunct to mechanical debridement. However, correct compliance with oral antimicrobial therapy in companion animals is often difficult. Cefovecin is a recently introduced veterinary cephalosporin that has demonstrated prolonged concentrations in extracellular fluid, allowing for dosing intervals of up to 14 days. Subgingival samples were collected from the oral cavity of 29 dogs and eight cats exhibiting grade 2 or grade 3 periodontal disease. Samples were cultivated on Wilkin Chalgrens agar and incubated in an anaerobic chamber for seven days. Selected anaerobic bacteria were isolated and identified to species level using 16S rRNA gene sequence analysis. Minimum inhibitory concentrations were determined for cefovecin and six additional antimicrobials using the agar dilution methodology recommended by the Clinical and Laboratory Standards Institute. The 65 clinical isolates were identified as Porphyromonas gulae (n = 45), Porphyromonas crevioricanis (n = 12), Porphyromonas macacae (n = 1), Porphyromonas cangingivalis (n = 1) Fusobacterium nucleatum (n = 2), Fusobacterium russii (n = 1) and Solobacterium moorei (n = 3). This is the first report of S. moorei being isolated from companion animals with periodontal disease. All isolates were highly susceptible to cefovecin, with a MIC90 of ≤0.125 μg/ml. Conversely, different resistance rates to ampicillin, amoxicillin and erythromycin between isolates were detected. Cefovecin is thus shown to be effective in vitro against anaerobic bacteria isolated from dogs and cats with periodontal disease.

  17. Anoxic and oxic phototrophic primary production during the Precambrian

    DEFF Research Database (Denmark)

    Ebey-Honeycutt, Christina Marie; Bjerrum, Christian J.; Canfield, Donald Eugene


    of the mixed layer often lies above the base of the photic zone . Thus, an ecosystem model for the Precambrian should reflect the net primary production (NPP) of oxygenic phototrophs in the mixed layer and anoxygenic phototrophs below (NPPox and NPPred, respectively). Satelite data and a vertically generalized...

  18. Experimental otitis media in gerbils and chinchillas with Streptococcus pneumoniae, Haemophilus influenzae, and other aerobic and anaerobic bacteria.


    Fulghum, R S; Brinn, J E; Smith, A M; Daniel, H J; Loesche, P J


    To ascertain the usefulness of Mongolian gerbils as an inbred model for otitis media, 52 Mongolian gerbils (Meriones unguiculatus, strain MONT/Tum) were compared with 26 chinchillas (Chinchilla laniger) for susceptibility to Streptococcus pneumoniae type 3. Haemophilus influenzae type b, and a polymicrobic culture including anaerobes (Streptococcus intermedius, Propionibacterium acnes, Staphylococcus epidermidis, and Corynebacterium sp.). Organisms were inoculated percutaneously into the supe...

  19. Biomarker evidence for widespread anaerobic methane oxidation in Mediterranean sediments by a consortium of methanogenic archae and bacteria

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Pancost, R.D.; Lint, S. de; Maarel, M.J.E.C. van der; Gottschal, J.C.


    Although abundant geochemical data indicate that anaerobic methane oxidation occurs in marine sediments, the linkage to specific microorganisms remains unclear. In order to examine processes of methane consumption and oxidation, sediment samples from mud volcanoes at two distinct sites on the Medite

  20. C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria. (United States)

    Azai, Chihiro; Tsukatani, Yusuke; Itoh, Shigeru; Oh-oka, Hirozo


    Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.

  1. Electron uptake by iron-oxidizing phototrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bose, A; Gardel, EJ; Vidoudez, C; Parra, EA; Girguis, PR


    Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

  2. Influence of decontamination on induction of arthritis in Lewis rats by cell wall fragments of Eubacterium aerofaciens. Arthropathic properties of indigenous anaerobic bacteria. (United States)

    Kool, J; Severijnen, A J; Klasen, I S; Gerrits-Boeye, M Y; Hazenberg, M P


    Although the cause (or causes) of rheumatoid arthritis is unknown, many workers have suggested that microorganisms play a part. The intestinal flora in particular has been related to the development of joint inflammation. It has been shown previously that cell wall fragments of several anaerobic Gram positive intestinal bacteria of human origin are arthritogenic after a single intraperitoneal injection in Lewis rats. The part played by indigenous microflora in this model has now been studied by decontaminating Lewis rats before the injection of Eubacterium aerofaciens cell wall fragments. The pattern and severity of arthritis appeared to be comparable in decontaminated and control rats. The second goal of this work was to isolate arthritogenic bacteria from the autochthonous intestinal flora of rats. Only a limited number of bacteria showing a resemblance to arthritogenic strains from human intestinal flora (i.e. E aerofaciens and Bifidobacterium adolescentis) could be isolated. These strains did not induce chronic arthritis after intraperitoneal injection. This may explain why spontaneous arthritis did not develop in Lewis rats. Images PMID:1586251

  3. Uniform designation for genes of the Calvin-Benson-Bassham reductive pentose phosphate pathway of bacteria

    NARCIS (Netherlands)

    Tabita, F. Robert; Gibson, Janet L.; Bowien, Botho; Dijkhuizen, Lubbert; Meijer, Wilhelmus


    Structural and regulatory genes encoding enzymes and proteins of the reductive pentose phosphate pathway have been isolated from a number of bacteria recently. In the phototroph Rhodobacter sphaeroides, and in two chemoautotrophic bacteria, Alcaligenes eutrophus and Xanthobacter flavus, these genes

  4. Indigenous cellulolytic and hemicellulolytic bacteria enhanced rapid co-composting of lignocellulose oil palm empty fruit bunch with palm oil mill effluent anaerobic sludge. (United States)

    Zainudin, Mohd Huzairi Mohd; Hassan, Mohd Ali; Tokura, Mitsunori; Shirai, Yoshihito


    The composting of lignocellulosic oil palm empty fruit bunch (OPEFB) with continuous addition of palm oil mill (POME) anaerobic sludge which contained nutrients and indigenous microbes was studied. In comparison to the conventional OPEFB composting which took 60-90 days, the rapid composting in this study can be completed in 40 days with final C/N ratio of 12.4 and nitrogen (2.5%), phosphorus (1.4%), and potassium (2.8%), respectively. Twenty-seven cellulolytic bacterial strains of which 23 strains were closely related to Bacillus subtilis, Bacillus firmus, Thermobifida fusca, Thermomonospora spp., Cellulomonas sp., Ureibacillus thermosphaericus, Paenibacillus barengoltzii, Paenibacillus campinasensis, Geobacillus thermodenitrificans, Pseudoxanthomonas byssovorax which were known as lignocellulose degrading bacteria and commonly involved in lignocellulose degradation. Four isolated strains related to Exiguobacterium acetylicum and Rhizobium sp., with cellulolytic and hemicellulolytic activities. The rapid composting period achieved in this study can thus be attributed to the naturally occurring cellulolytic and hemicellulolytic strains identified.

  5. Microenvironmental Ecology of Phototrophs from Extreme Environments

    DEFF Research Database (Denmark)

    Trampe, Erik

    and finalized in part of my master thesis and presents a new multicolor (red, green, and blue excitation light) system for microscopic imaging of variable chlorophyll fluorescence. In addition to a thorough description of the commercially available imaging system, we developed an additional custom build......In the three manuscripts presented in part one of this thesis, I analyse the physicochemical parameters, microenvironmental ecology and species composition of microbial phototrophs in ikaite tufa columns. This work was not easy, and encompassed underwater sampling and microsensor work demanding...... of which have now been tentatively identified taxonomically, and their phylogenetic relationships been evaluated (Manuscript 3). Part 2 of the thesis includes three manuscripts that focus on cyanobacteria that have evolved special photopigments in contrast to other cyanobacteria. In Manuscript 4 we show...

  6. Engineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    James C. Liao


    This project is a collaboration with F. R. Tabita of Ohio State. Our major goal is to understand the factors and regulatory mechanisms that influence hydrogen production. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Our part of the project was to develop a modeling technique to investigate the metabolic network in connection to hydrogen production and regulation. Organisms must balance the pathways that generate and consume reducing power in order to maintain redox homeostasis to achieve growth. Maintaining this homeostasis in the nonsulfur purple photosynthetic bacteria is a complex feat with many avenues that can lead to balance, as these organisms possess versatile metabolic capabilities including anoxygenic photosynthesis, aerobic or anaerobic respiration, and fermentation. Growth is achieved by using H{sub 2} as an electron donor and CO{sub 2} as a carbon source during photoautotrophic and chemoautotrophic growth, where CO{sub 2} is fixed via the Calvin-Benson-Bassham (CBB) cycle. Photoheterotrophic growth can also occur when alternative organic carbon compounds are utilized as both the carbon source and electron donor. Regardless of the growth mode, excess reducing equivalents generated as a result of oxidative processes, must be transferred to terminal electron acceptors, thus insuring that redox homeostasis is maintained in the cell. Possible terminal acceptors include O{sub 2}, CO{sub 2}, organic carbon, or various oxyanions. Cells possess regulatory mechanisms to balance the activity of the pathways which supply energy, such as photosynthesis, and those that consume energy, such as CO{sub 2} assimilation or N{sub 2} fixation. The major route for CO{sub 2} assimilation is the CBB

  7. Molecular Fingerprint and Dominant Environmental Factors of Nitrite-Dependent Anaerobic Methane-Oxidizing Bacteria in Sediments from the Yellow River Estuary, China (United States)

    Yan, Pengze; Li, Mingcong; Wei, Guangshan; Li, Han; Gao, Zheng


    Nitrite-dependent anaerobic methane oxidation (n-damo) is performed by “Candidatus Methylomirabilis oxyfera” (M. oxyfera), which connects the carbon and nitrogen global nutrient cycles. In the present study, M. oxyfera-like bacteria sequences were successfully recovered from Yellow River Estuary sediments using specific primers for 16S rRNA and pmoA genes. A M. oxyfera-like sequences analysis based on the 16S rRNA gene revealed greater diversity compared with the pmoA gene; the 16S rRNA gene sequences retrieved from the Yellow River Estuary sediments belong to groups A as well as B and were mainly found in freshwater habitats. Quantitative PCR showed that 16S rRNA gene abundance varied from 9.28±0.11×103 to 2.10±0.13×105 copies g-1 (dry weight), and the pmoA gene abundance ranged from 8.63±0.50×103 to 1.83±0.18×105 copies g-1 (dry weight). A correlation analysis showed that the total organic carbon (TOC) and ammonium (NH4+) as well as the ratio of total phosphorus to total nitrogen (TP/TN) influenced the M. oxyfera-like bacteria distribution in the Yellow River Estuary sediments. These findings will aid in understanding the n-damo bacterial distribution pattern as well as their correlation with surrounding environmental factors in temperate estuarine ecosystems. PMID:26368535

  8. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt


    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

  9. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria (United States)

    Byrne, James M.; Klueglein, Nicole; Pearce, Carolyn; Rosso, Kevin M.; Appel, Erwin; Kappler, Andreas


    Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.

  10. Oxygen suppresses light-driven anodic current generation by a mixed phototrophic culture. (United States)

    Darus, Libertus; Ledezma, Pablo; Keller, Jürg; Freguia, Stefano


    This paper describes the detrimental effect of photosynthetically evolved oxygen on anodic current generation in the presence of riboflavin upon illumination of a mixed phototrophic culture enriched from a freshwater pond at +0.6 V vs standard hydrogen electrode. In the presence of riboflavin, the phototrophic biomass in the anodic compartment produced an electrical current in response to light/dark cycles (12 h/12 h) over 12 months of operation, generating a maximum current density of 17.5 mA x m(-2) during the dark phase, whereas a much lower current of approximately 2 mA x m(-2) was generated during illumination. We found that the low current generation under light exposure was caused by high rates of reoxidation of reduced riboflavin by oxygen produced during photosynthesis. Quantification of biomass by fluorescence in situ hybridization images suggested that green algae were predominant in both the anode-based biofilm (55.1%) and the anolyte suspension (87.9%) with the remaining biovolume accounted for by bacteria. Genus-level sequencing analysis revealed that bacteria were dominated by cyanobacterium Leptolyngbia (∼35%), while the prevailing algae were Dictyosphaerium, Coelastrum, and Auxenochlorella. This study offers a key comprehension of mediator sensitivity to reoxidation by dissolved oxygen for improvement of microbial solar cell performance.

  11. Bioengineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Tabita, F. Robert [The Ohio State University


    In this study, the Principal Investigator, F.R. Tabita has teemed up with J. C. Liao from UCLA. This project's main goal is to manipulate regulatory networks in phototrophic bacteria to affect and maximize the production of large amounts of hydrogen gas under conditions where wild-type organisms are constrained by inherent regulatory mechanisms from allowing this to occur. Unrestrained production of hydrogen has been achieved and this will allow for the potential utilization of waste materials as a feed stock to support hydrogen production. By further understanding the means by which regulatory networks interact, this study will seek to maximize the ability of currently available “unrestrained” organisms to produce hydrogen. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Moreover, due to their great metabolic versatility, such organisms highly regulate these processes in the cell and since virtually all such capabilities are dispensable, excellent experimental systems to study aspects of molecular control and biochemistry/physiology are available.

  12. Acid pre-treatment of sewage anaerobic sludge to increase hydrogen producing bacteria HPB: effectiveness and reproducibility. (United States)

    Tommasi, T; Sassi, G; Ruggeri, B


    The present study is aimed to test the effectiveness and the reproducibility of the acid pre-treatment of sewage sludge to suppress the methanogenic bacteria activity, in order to increase the hydrogen forming bacteria activity, mainly Clostridium species. The treated sludge has been tested on glucose reach medium under mesophilic conditions (35 degrees C), in batch mode to quantify the biological fermentative hydrogen production. In the whole series of experiments, the main components of biogas are hydrogen (52-60%) and carbon dioxide (40-48%); no methane and hydrogen sulphide were present in it. The rate of biogas production reached a maximum of 75 ml/lh. An overall mean hydrogen conversion efficiency was 11.20% on the assumption of maximum of 3 mol H2/mol glucose. Clostridium spp. multiplied ten times after 10 h of fermentation and over that thousand times at the end of fermentation.

  13. 玛珥湖好氧不产氧光合细菌pufM基因DNA和mRNA的定量及多样性分析%Genetic diversity and quantification of aerobic anoxygenic phototrophic bacteria in Hugangyan Maar Lake based on pufM DNA and mRNA analysis

    Institute of Scientific and Technical Information of China (English)

    陈晓洁; 曾永辉; 简纪常; 鲁义善; 吴灶和


    [Objective] Maar lake is a special type of Crater Lake.Huguangyan Maar Lake was formed about 140 k-160 k years ago, fully closed, and has not yet been affected by human activities, where abundant and novel microbial species might dwell as reported previously.Aerobic anoxygenic phototrophic bacteria (AAPB) is a functional bacterial group with long evolution history in Earth possessing unique physiological and ecological characteristics.To date, our knowledge about AAPB distribution in Maar Lake is still blank.[Methods] Here, by constructing and analyzing six clone libraries of the photosynthetic reaction center pufM gene from total DNA and RNA, respectively, with 1 m, 5 m, and 12 m water layers in Huguangyan Maar Lake, and combining quantitative Real-time PCR, we studied AAPB's distribution, phy-logenetic diversity and the proportion in the total bacteria in different water layers.The results of coverage value and rarefaction curves of six libraries showed that AAPB diversity was sampled well for the purpose of revealing the diversity of main AAPB groups in each water layer.[Results] BLAST analysis showed that pufM sequences in Maar Lake were 80%-93% similar to public sequences.Diversity index indicated that the AAPB diversity in surface and deep layers was similar, whereas diversity in the intermediate layer was lowest.In view of total RNA and DNA data, pufM RNA diversity was higher than that of DNA.Phylogenetic and statistical analysis revealed that 49.43% sequences are fell into the OTUs 21-24 which were closely related to P-proteobacteria and represent dominated AAPB groups.Quantitative PCR results showed that the percentage of AAPB in total bacteria in 1 m water layer reached a highest value of 38.06%, whereas only 0.85% and 9.54% in 5 m and 12 m, respectively.[Conclusion] Huguangyan Maar Lake is occupied by rich and diverse AAPB groups.%[目的]湖光岩玛珥湖是一类特殊的火山口湖,它完全封闭,地质年代久远,尚未受人类活动的剧烈

  14. Experimental otitis media in gerbils and chinchillas with Streptococcus pneumoniae, Haemophilus influenzae, and other aerobic and anaerobic bacteria. (United States)

    Fulghum, R S; Brinn, J E; Smith, A M; Daniel, H J; Loesche, P J


    To ascertain the usefulness of Mongolian gerbils as an inbred model for otitis media, 52 Mongolian gerbils (Meriones unguiculatus, strain MONT/Tum) were compared with 26 chinchillas (Chinchilla laniger) for susceptibility to Streptococcus pneumoniae type 3. Haemophilus influenzae type b, and a polymicrobic culture including anaerobes (Streptococcus intermedius, Propionibacterium acnes, Staphylococcus epidermidis, and Corynebacterium sp.). Organisms were inoculated percutaneously into the superior chamber of the middle ear bulla. The gerbils and chinchillas shared similar susceptibilities and responses to the inoculated organisms as determined by X-ray, otoscopic, histopathological, and microbiological determinations at 5 to 7 days. Koch's postulate studies proved the role of S. pneumoniae and H. influenzae in the pathology found in both animal models. The animals were also susceptible to the polymicrobic culture, although the relative virulence of the individual members of this mixture was low, suggesting that these species potentiated as a polymicrobic mixture. The Corynebacterium sp. appeared to elicit the greatest histopathological response in chronic (8-week) studies in gerbils. The gerbils were found to be useful as an alternative animal model for the study of otitis media of bacterial etiology.

  15. Group-specific PCR-RFLP and real-time PCR methods for detection and tentative discrimination of strictly anaerobic beer-spoilage bacteria of the class Clostridia. (United States)

    Juvonen, Riikka; Koivula, Teija; Haikara, Auli


    The strictly anaerobic brewery contaminants of the genera Pectinatus, Megasphaera, Selenomonas and Zymophilus in the class Clostridia constitute an important group of spoilage bacteria of unpasteurised, packaged beers. The aim of this study was to develop and evaluate group-specific PCR methods to detect and differentiate these bacteria in beer. A group-specific primer pair targeting a 342-bp variable region of the 16S rRNA gene was designed and evaluated in end-point PCR with gel electrophoresis and in real-time PCR with SYBR Green I dye. Significant cross-reactions with DNAs from any of the forty-two brewery-related, non-target microbes or from real brewery samples were not detected in either PCR system. The group-specific end-point and real-time PCR products could be differentiated according to species/genus and spoilage potential using restriction fragment length polymorphism (KpnI, XmnI, BssHII, ScaI) and melting point curve analysis, respectively. In combination with a rapid DNA extraction method, the PCR reactions detected ca 10(0)-10(3) CFU per 25 ml of beer depending on the strain and on the PCR system. The end-point and real-time PCR analysis took 6-7 h and 2-3 h, respectively. Pre-PCR enrichment of beer samples for 1-3 days ensured the detection of even a single cultivable cell. The PCR and cultivation results of real brewery samples were mostly congruent but the PCR methods were occasionally more sensitive. The PCR methods developed allow the detection of all the nine beer-spoilage Pectinatus, Megasphaera, Selenomonas and Zymophilus species in a single reaction and their differentiation below group level and reduce the analysis time for testing of their presence in beer samples by 1-2 days. The methods can be applied for brewery routine quality control and for studying occurrence, diversity and numbers of the strictly anaerobic beer spoilers in the brewing process.

  16. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B


    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole...... weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment....

  17. Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors (United States)

    Baesman, S.M.; Bullen, T.D.; Dewald, J.; Zhang, Dongxiao; Curran, S.; Islam, F.S.; Beveridge, T.J.; Oremland, R.S.


    Certain toxic elements support the metabolism of diverse prokaryotes by serving as respiratory electron acceptors for growth. Here, we demonstrate that two anaerobes previously shown to be capable of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental tellurium [Te(0)]. This reduction achieves a sizeable stable-Te-isotopic fractionation (isotopic enrichment factor [??] = -0.4 to -1.0 per ml per atomic mass unit) and results in the formation of unique crystalline Te(0) nanoarchitectures as end products. The Te(0) crystals occur internally within but mainly externally from the cells, and each microorganism forms a distinctly different structure. Those formed by Bacillus selenitireducens initially are nanorods (???10-nm diameter by 200-nm length), which cluster together, forming larger (???1,000-nm) rosettes composed of numerous individual shards (???100-nm width by 1,000-nm length). In contrast, Sulfurospirillium barnesii forms extremely small, irregularly shaped nanospheres (diameter < 50 nm) that coalesce into larger composite aggregates. Energy-dispersive X-ray spectroscopy and selected area electron diffraction indicate that both biominerals are composed entirely of Te and are crystalline, while Raman spectroscopy confirms that they are in the elemental state. These Te biominerals have specific spectral signatures (UV-visible light, Raman) that also provide clues to their internal structures. The use of microorganisms to generate Te nanomaterials may be an alternative for bench-scale syntheses. Additionally, they may also generate products with unique properties unattainable by conventional physical/chemical methods. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

  18. Quantification of enteric viruses, pathogen indicators, and Salmonella bacteria in class B anaerobically digested biosolids by culture and molecular methods. (United States)

    Wong, Kelvin; Onan, Brandon M; Xagoraraki, Irene


    The most common class B biosolids in the United States are generated by mesophilic anaerobic digestion (MAD), and MAD biosolids have been used for land application. However, the pathogen levels in MAD biosolids are still unclear, especially with respect to enteric viruses. In this study, we determined the occurrence and the quantitative levels of enteric viruses and indicators in 12 MAD biosolid samples and of Salmonella enterica in 6 MAD biosolid samples. Three dewatered biosolid samples were also included in this study for purposes of comparison. Human adenoviruses (HAdV) had the highest gene levels and were detected more frequently than other enteric viruses. The gene levels of noroviruses (NV) reported were comparable to those of enteroviruses (EV) and human polyomaviruses (HPyV). The occurrence percentages of HAdV, HAdV species F, EV, NV GI, NV GII, and HPyV in MAD samples were 83, 83, 42, 50, 75, and 58%, respectively. No hepatitis A virus was detected. Infectious HAdV was detected more frequently than infectious EV, and all infectious HAdV were detected when samples were propagated in A549 cells. Based on most-probable-number (MPN) analysis, A549 cells were more susceptible to biosolid-associated viruses than BGM cells. All indicator levels in MAD biosolids were approximately 10(4) MPN or PFU per gram (dry), and the dewatered biosolids had significantly higher indicator levels than the MAD biosolids. Only two MAD samples tested positive for Salmonella enterica, where the concentration was below 1.0 MPN/4 g. This study provides a broad comparison of the prevalence of different enteric viruses in MAD biosolids and reports the first detection of noroviruses in class B biosolids. The observed high quantitative and infectivity levels of adenoviruses in MAD biosolids indicate that adenovirus is a good indicator for the evaluation of sludge treatment efficiency.

  19. Horizontal gene transfer from Bacteria to rumen Ciliates indicates adaptation to their anaerobic, carbohydrates-rich environment

    Directory of Open Access Journals (Sweden)

    Takenaka Akio


    Full Text Available Abstract Background The horizontal transfer of expressed genes from Bacteria into Ciliates which live in close contact with each other in the rumen (the foregut of ruminants was studied using ciliate Expressed Sequence Tags (ESTs. More than 4000 ESTs were sequenced from representatives of the two major groups of rumen Cilates: the order Entodiniomorphida (Entodinium simplex, Entodinium caudatum, Eudiplodinium maggii, Metadinium medium, Diploplastron affine, Polyplastron multivesiculatum and Epidinium ecaudatum and the order Vestibuliferida, previously called Holotricha (Isotricha prostoma, Isotricha intestinalis and Dasytricha ruminantium. Results A comparison of the sequences with the completely sequenced genomes of Eukaryotes and Prokaryotes, followed by large-scale construction and analysis of phylogenies, identified 148 ciliate genes that specifically cluster with genes from the Bacteria and Archaea. The phylogenetic clustering with bacterial genes, coupled with the absence of close relatives of these genes in the Ciliate Tetrahymena thermophila, indicates that they have been acquired via Horizontal Gene Transfer (HGT after the colonization of the gut by the rumen Ciliates. Conclusion Among the HGT candidates, we found an over-representation (>75% of genes involved in metabolism, specifically in the catabolism of complex carbohydrates, a rich food source in the rumen. We propose that the acquisition of these genes has greatly facilitated the Ciliates' colonization of the rumen providing evidence for the role of HGT in the adaptation to new niches.

  20. Horizontal gene transfer from Bacteria to rumen Ciliates indicates adaptation to their anaerobic, carbohydrates-rich environment (United States)

    Ricard, Guénola; McEwan, Neil R; Dutilh, Bas E; Jouany, Jean-Pierre; Macheboeuf, Didier; Mitsumori, Makoto; McIntosh, Freda M; Michalowski, Tadeusz; Nagamine, Takafumi; Nelson, Nancy; Newbold, Charles J; Nsabimana, Eli; Takenaka, Akio; Thomas, Nadine A; Ushida, Kazunari; Hackstein, Johannes HP; Huynen, Martijn A


    Background The horizontal transfer of expressed genes from Bacteria into Ciliates which live in close contact with each other in the rumen (the foregut of ruminants) was studied using ciliate Expressed Sequence Tags (ESTs). More than 4000 ESTs were sequenced from representatives of the two major groups of rumen Cilates: the order Entodiniomorphida (Entodinium simplex, Entodinium caudatum, Eudiplodinium maggii, Metadinium medium, Diploplastron affine, Polyplastron multivesiculatum and Epidinium ecaudatum) and the order Vestibuliferida, previously called Holotricha (Isotricha prostoma, Isotricha intestinalis and Dasytricha ruminantium). Results A comparison of the sequences with the completely sequenced genomes of Eukaryotes and Prokaryotes, followed by large-scale construction and analysis of phylogenies, identified 148 ciliate genes that specifically cluster with genes from the Bacteria and Archaea. The phylogenetic clustering with bacterial genes, coupled with the absence of close relatives of these genes in the Ciliate Tetrahymena thermophila, indicates that they have been acquired via Horizontal Gene Transfer (HGT) after the colonization of the gut by the rumen Ciliates. Conclusion Among the HGT candidates, we found an over-representation (>75%) of genes involved in metabolism, specifically in the catabolism of complex carbohydrates, a rich food source in the rumen. We propose that the acquisition of these genes has greatly facilitated the Ciliates' colonization of the rumen providing evidence for the role of HGT in the adaptation to new niches. PMID:16472398

  1. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt


    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism, substrate affinity and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal was examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species causes the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, neither hydrogen nor formate is exchanged fast enough between the consortia partners to achieve measured rates of metabolic activity, but that acetate exchange might support rates that approach those observed.

  2. Influence of an aerobic fungus grown on solid culture on ruminal degradability and on a mixture culture of anaerobic cellulolytic bacteria. (United States)

    Hernández-Díaz, R; Pimentel-González, D J; Figueira, A C; Viniegra-González, G; Campos-Montiel, R G


    In this work, the effect of a solid fungal culture of Aspergillus niger (An) grown on coffee pulp on the in situ ruminal degradability (RD) of corn stover was evaluated. In addition, the effect of its extracts on the in vitro dry matter disappearance (IVDMD) and on a mixed culture of anaerobic cellulolytic bacteria (MCACB) was also investigated. The solid ferment was a crude culture of An, grown on coffee pulp. Regarding in situ RD, a significant difference (p < 0.05) was found between treatment with 200 g/day of the solid culture and control (no solid culture added) on dry matter, crude protein and neutral detergent fibre on RD. All the water extracts (pH 4, 7 and 10) enhanced IVDMD and stimulated the cellulolytic activity on a MCACB. Ultrafiltration results showed that active compounds with a molecular weight lower than 30 kDa were responsible for the effect on MCACB. Such results suggest that the effects of the solid An culture in RD are related to the presence of water soluble compounds having a molecular weight lower than 30 kDa.

  3. Effect of Growth Promoting Bacteria on the Growth Rate and Lipid Content of Microalgae Chorella sp in Sludge Liquor of Anaerobic Digester of Dairy Manure

    Directory of Open Access Journals (Sweden)

    Wahyunanto A. Nugroho


    Full Text Available Microalgae are microorganisms that have potential as biofuel feedstock since it has relatively high content of lipid. To be economically feasible, microalgae has to be cultivated in lower operational cost. Liquor of anaerobic sludge is one of the choices since it contents high concentration in nutrient. To boost its productivity, growth promoting bacteria (GPB was added in the medium. The objective of this research is to observe the influence of GPB on the growth rate and oil content of the algae. The experiment used three treatment in respect to the dose of GPB added to the medium, and was done in triplicate. The three treatments are A3 (spiked with 3 ml of GPB inoculum, A6 (spiked with 6 ml of GPB inoculum and A9 (spiked with 9 ml of GPB inoculum, and one more treatment as a control (A0. Result showed that the higher the dose of GPB added, the higher the lipid content of microalgae. For the growth rate of microalga, the highest growth rate was observed on A6 treatment, while the lowest one was observed on the control.

  4. Carbon conversion efficiency and population dynamics of a marine algae–bacteria consortium growing on simplified synthetic digestate: First step in a bioprocess coupling algal production and anaerobic digestion


    Vasseur, C.; Bougaran, G.; Garnier, M.; Hamelin, J.; Leboulanger, Christophe; Le Chevanton, M.; Mostajir, B; Sialve, B.; Steyer, J. P.; Fouilland, E.


    Association of microalgae culture and anaerobic digestion seems a promising technology for sustainable algal biomass and biogas production. The use of digestates for sustaining the growth of microalgae reduces the costs and the environmental impacts associated with the substantial algal nutrient requirements. A natural marine algae–bacteria consortium was selected by growing on a medium containing macro nutrients (ammonia, phosphate and acetate) specific of a digestate, and was submitted to a...

  5. Biological sulphide removal from anaerobically treated domestic sewage: reactor performance and microbial community dynamics. (United States)

    Garcia, Graziella Patrício Pereira; Diniz, Renata Côrtes Oliveira; Bicalho, Sarah Kinaip; Franco, Vitor Araujo de Souza; Gontijo, Eider Max de Oliveira; Toscano, Rodrigo Argolo; Canhestro, Kenia Oliveira; Santos, Merly Rita Dos; Carmo, Ana Luiza Rodrigues Dias; Lobato, Livia Cristina S; Brandt, Emanuel Manfred F; Chernicharo, Carlos A L; Calabria de Araujo, Juliana


    We developed a biological sulphide oxidation system and evaluated two reactors (shaped similar to the settler compartment of an up-flow anaerobic sludge blanket [UASB] reactor) with different support materials for biomass retention: polypropylene rings and polyurethane foam. The start-up reaction was achieved using microorganisms naturally occurring on the open surface of UASB reactors treating domestic wastewater. Sulphide removal efficiencies of 65% and 90% were achieved with hydraulic retention times (HRTs) of 24 and 12 h, respectively, in both reactors. However, a higher amount of elemental sulphur was formed and accumulated in the biomass from reactor 1 (20 mg S(0) g(-1) VTS) than in that from reactor 2 (2.9 mg S(0) g(-1) VTS) with an HRT of 24 h. Denaturing gradient gel electrophoresis (DGGE) results revealed that the the pink and green biomass that developed in both reactors comprised a diverse bacterial community and had sequences related to phototrophic green and purple-sulphur bacteria such as Chlorobium sp., Chloronema giganteum, and Chromatiaceae. DGGE band patterns also demonstrated that bacterial community was dynamic over time within the same reactor and that different support materials selected for distinct bacterial communities. Taken together, these results indicated that sulphide concentrations of 1-6 mg L(-1) could be efficiently removed from the effluent of a pilot-scale UASB reactor in two sulphide biological oxidation reactors at HRTs of 12 and 24 h, showing the potential for sulphur recovery from anaerobically treated domestic wastewater.

  6. Isolation of three anaerobic electrogenic bacteria and their physiological and biochemical properties%3株厌氧产电菌的分离与特性

    Institute of Scientific and Technical Information of China (English)

    邹然; 朱葛夫; 张净瑞; 刘紫璇; 刘超翔; 黄栩


    Three anaerobic electrogenic bacteria named as Z1,Z2 and Z3 were isolated from a microbial electrolysis cell (MEC) by the method of Hungate roll tube. Phylogenetic analysis based on 16S rDNA gene sequence indicated that strain Z1 belonged to Citrobacter,while both strain Z2 and Z3 belonged to Clostridium. The physiological and biochemical characteristics showed that Z1 was facultative anaerobe,while Z2 and Z3 were strict anaerobes. Z1,Z2 and Z3 could tolerate acidic pH conditions,and the optimum pH level was 5 to 7.5. The optimum temperature of Z1 was 35 ℃,while the optimum temperature of Z2 and Z3 was 30 ℃. The optimum NaCl concentration range of three strains was 0.1%to 2.0%. Sucrose,starch,sodium propionate,sodium acetate could be used as their carbon sources. The study of electrocatalytic activity showed that these strains all had a reduction peak at voltage of -0.29 V and they were applicable for the cathode of microbial fuel cell (MFC). The adding of a mixture of three kinds of strains might significantly shorten the time of start-up stage of MFC and enhance electricity production efficiency by 18.1%.%采用Hungate厌氧菌培养技术从微生物电解池(MEC)中分离得到3株厌氧产电菌Z1、Z2和Z3。16S rDNA基因测序和系统发育树构建结果表明,Z1属于柠檬酸杆菌属(Citrobacter),Z2和Z3属于梭菌属(Clostridium)。生理生化特性研究表明,Z1为兼性厌氧菌,Z2和 Z3为严格厌氧菌;3种菌株能够耐受较酸的 pH 值条件,在pH值为5~7.5的环境中增殖良好;Z1的最适生长温度为35℃,Z2和Z3的最适生长温度为30℃;3种菌株的最适NaCl浓度为0.1%~2.0%;均能以蔗糖、淀粉、丙酸钠、乙酸钠等为碳源生长。产电活性测试试验表明,3种菌株在-0.29 V时具有较大还原峰,氧化峰不明显,适用于微生物燃料电池(MFC)的阴极。在MFC的启动试验中,加入3种菌株的混合物后,可显著缩短其启动周期

  7. Physiological response of BSC phototrophic community to EPS removal (United States)

    Adessi, Alessandra; Cruz de Carvalho, Ricardo; Silvestre, Susana; Rossi, Federico; Mugnai, Gianmarco; Marques da Silva, Jorge; Branquinho, Cristina; De Philippis, Roberto


    Biological Soil Crusts (BSCs) are associations between soil particles and varying proportions of cyanobacteria, heterotrophic bacteria, algae, fungi, lichens and mosses. BSCs play a major role in soil stabilization, and in drylands have been well acknowledged for mitigating desertification effects. Amongst the wide diversity of organisms that compose BSCs, cyanobacteria are the first primary producers: they colonize nutrient-limited soils, modifying the micro-environment through the excretion of large amounts of extracellular polymeric substances (EPSs). EPSs represent a huge carbon and nitrogen source for other inhabitants of the crust, are three-dimensionally spread through the first millimeters of the soil, and have a recognized role in influencing the hydrological behavior of the crust. The aim of this study was to investigate the possible role that EPSs play in the physiology of the phototrophic community residing on a light crust (without mosses or lichens, thus mainly inhabited by cyanobacteria and algae). In particular it was investigated whether the three-dimensional matrix in which EPSs are organized allowed light distribution and diffusion inside the crust, thus influencing photosynthesis. Non-invasive techniques were used to extract the polymeric matrix and to analyze photosynthetic performances in native and extracted BSC samples. Preliminary results suggested that the mild extraction protocol allowed to remove a portion of the matrix, and that this treatment revealed highly significant differences in the optical properties of the crusts comparing native and extracted samples. The extraction did not affect cell viability, as samples after the extraction were still photosynthetically active. However, chlorophyll variable fluorescence was significantly lower in the extracted samples than in native ones, and susceptibility to photoinhibition was significantly modified. Evaluating the role of the EPSs in the community is essential to further understand the

  8. Mineral and non-carbon nutrient utilization and recovery during sequential phototrophic-heterotrophic growth of lipid-rich algae. (United States)

    Bohutskyi, Pavlo; Liu, Kexin; Kessler, Ben A; Kula, Thomas; Hong, Yongseok; Bouwer, Edward J; Betenbaugh, Michael J; Allnutt, F C Thomas


    A critical factor in implementing microalgal biofuels for mass production is the nutrient requirements. The current study investigated the fate of macro- and micronutrients and their availability in a sequential phototrophic-heterotrophic production process for the lipid rich microalga Auxenochlorella protothecoides. More than 99 % (by weight) of overall process nutrients were supplied during the initial photoautotrophic stage reflecting its significantly larger volume. Under photoautotrophic growth conditions only 9-35 % of supplied Mn, S, Fe, N, Mg, and Cu and less than 5 % of P, Mo, Co, B, Zn, and Ca were consumed by the algae. The rest of these nutrients remain in the spent growth media during the culture concentration-down from an 800 L phototrophic pond to a 5 L heterotrophic fermenter. In contrast, Zn, Mo, Mn, Mg, Ca, and N were exhausted (90-99 % removal) during the first 25 h of the heterotrophic growth stage. The depletion of these key nutrients may have ultimately limited the final biomass density and/or lipid productivity achieved. Approximately 10-20 % of the total supplied S, Mn, Fe, N, and Cu and 5 % of Ca and Zn were assimilated into algal biomass. Several elements including N, P, Mn, B, Cu, Ca, Mg, S, and Fe were released back into the liquid phase by anaerobic digestion (AD) of the residual biomass after lipid extraction. The nutrients recovered from the AD effluent and remaining in the spent medium should be recycled or their initial concentration to the phototrophic stage decreased to enhance process economics and sustainability for future commercialization of algal-derived biofuels.

  9. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella


    Full Text Available 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

  10. Reductive dehalogenation by anaerobic bacteria.

    NARCIS (Netherlands)

    Holliger, C.


    The understanding of the fate of synthetic halogenated hydrocarbons became a matter of major interest over the last two decades. Halogenated compounds may threaten ecosystems due to their biocide properties. The degradability of halocompounds determines whether they will accumulate in a certain envi

  11. Analysis of a marine phototrophic biofilm by confocal laser scanning microscopy using the new image quantification software PHLIP

    Directory of Open Access Journals (Sweden)

    Almeida Jonas S


    Full Text Available Abstract Background Confocal laser scanning microscopy (CLSM is the method of choice to study interfacial biofilms and acquires time-resolved three-dimensional data of the biofilm structure. CLSM can be used in a multi-channel modus where the different channels map individual biofilm components. This communication presents a novel image quantification tool, PHLIP, for the quantitative analysis of large amounts of multichannel CLSM data in an automated way. PHLIP can be freely downloaded from Results PHLIP is an open source public license Matlab toolbox that includes functions for CLSM imaging data handling and ten image analysis operations describing various aspects of biofilm morphology. The use of PHLIP is here demonstrated by a study of the development of a natural marine phototrophic biofilm. It is shown how the examination of the individual biofilm components using the multi-channel capability of PHLIP allowed the description of the dynamic spatial and temporal separation of diatoms, bacteria and organic and inorganic matter during the shift from a bacteria-dominated to a diatom-dominated phototrophic biofilm. Reflection images and weight measurements complementing the PHLIP analyses suggest that a large part of the biofilm mass consisted of inorganic mineral material. Conclusion The presented case study reveals new insight into the temporal development of a phototrophic biofilm where multi-channel imaging allowed to parallel monitor the dynamics of the individual biofilm components over time. This application of PHLIP presents the power of biofilm image analysis by multi-channel CLSM software and demonstrates the importance of PHLIP for the scientific community as a flexible and extendable image analysis platform for automated image processing.

  12. Succession of lignocellulolytic bacterial consortia bred anaerobically from lake sediment

    NARCIS (Netherlands)

    Korenblum, Elisa; Jiménez Avella, Diego; van Elsas, Jan


    Anaerobic bacteria degrade lignocellulose in various anoxic and organically rich environments, often in a syntrophic process. Anaerobic enrichments of bacterial communities on a recalcitrant lignocellulose source were studied combining polymerase chain reaction–denaturing gradient gel electrophoresi

  13. A new extreme environment for aerobic anoxygenic phototrophs: biological soil crusts. (United States)

    Csotonyi, Julius T; Swiderski, Jolantha; Stackebrandt, Erko; Yurkov, Vladimir


    Biological soil crusts improve the health of arid or semiarid soils by enhancing water content, nutrient relations and mechanical stability, facilitated largely by phototrophic microorganisms. Until recently, only oxygenic phototrophs were known from soil crusts. A recent study has demonstrated the presence of aerobic representatives of Earth's second major photosynthetic clade, the evolutionarily basal anoxygenic phototrophs. Three Canadian soil crust communities yielded pink and orange aerobic anoxygenic phototrophic strains possessing the light-harvesting pigment bacteriochlorophyll a. At relative abundances of 0.1-5.9% of the cultivable bacterial community, they were comparable in density to aerobic phototrophs in other documented habitats. 16S rDNA sequence analysis revealed the isolates to be related to Methylobacterium, Belnapia, Muricoccus and Sphingomonas. This result adds a new type of harsh habitat, dry soil environments, to the environments known to support aerobic anoxygenic phototrophs.

  14. Microscale sulfur cycling in the phototrophic pink berry consortia of the Sippewissett Salt Marsh. (United States)

    Wilbanks, Elizabeth G; Jaekel, Ulrike; Salman, Verena; Humphrey, Parris T; Eisen, Jonathan A; Facciotti, Marc T; Buckley, Daniel H; Zinder, Stephen H; Druschel, Gregory K; Fike, David A; Orphan, Victoria J


    Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the 'pink berry' consortia of the Sippewissett Salt Marsh through an integrative study at the microbial scale. The pink berries are macroscopic, photosynthetic microbial aggregates composed primarily of two closely associated species: sulfide-oxidizing purple sulfur bacteria (PB-PSB1) and sulfate-reducing bacteria (PB-SRB1). Using metagenomic sequencing and (34) S-enriched sulfate stable isotope probing coupled with nanoSIMS, we demonstrate interspecies transfer of reduced sulfur metabolites from PB-SRB1 to PB-PSB1. The pink berries catalyse net sulfide oxidation and maintain internal sulfide concentrations of 0-500 μm. Sulfide within the berries, captured on silver wires and analysed using secondary ion mass spectrometer, increased in abundance towards the berry interior, while δ(34) S-sulfide decreased from 6‰ to -31‰ from the exterior to interior of the berry. These values correspond to sulfate-sulfide isotopic fractionations (15-53‰) consistent with either sulfate reduction or a mixture of reductive and oxidative metabolisms. Together this combined metagenomic and high-resolution isotopic analysis demonstrates active sulfur cycling at the microscale within well-structured macroscopic consortia consisting of sulfide-oxidizing anoxygenic phototrophs and sulfate-reducing bacteria.


    Directory of Open Access Journals (Sweden)

    M. S. Tabib


    Full Text Available Anaerobic bacteria are well known causes of sepsis in adults but there are few studies regarding their role in neonatal sepsis. In an attempt to define the incidence of neonatal anaerobic infections a prospective study was performed during one year period. A total number of 400 neonates under sepsis study were entered this investigation. Anaerobic as well as aerobic cultures were sent. The patients were subjected to comparison in two groups: anaerobic culture positive and anaerobic culture negative and this comparison were analyzed statistically. There were 7 neonates with positive anaerobic culture and 35 neonates with positive aerobic culture. A significant statistical relationship was found between anaerobic infections and abdominal distention and pneumonia. It is recommended for those neonates with abdominal distention and pneumonia refractory to antibiotic treatment to be started on antibiotics with anaerobic coverage.

  16. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)


    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.

  17. Competition and coexistence of sulfate-reducing bacteria, acetogens and methanogens in a lab-scale anaerobic bioreactor as affected by changing substrate to sulfate ratio

    NARCIS (Netherlands)

    Dar, S.A.; Kleerebezem, R.; Stams, A.J.M.; Kuenen, J.G.; Muyzer, G.


    The microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. T

  18. The isolation of anaerobic bacteria from the gut of Camponotus japonicus%日本弓背蚁消化道厌氧细菌的分离培养

    Institute of Scientific and Technical Information of China (English)

    朱卓琳; 南小宁; 王云果; 贺虹


    Objectives] An anaerobic device was designed to culture anaerobic bacteria from the digestive tract of Camponotus japonicus. [Methods] A simple anaerobic device; the Interlayer Petri Dish Method, was improved to isolate anaerobic bacteria from the digestive tract of C. japonicus using four kinds of culture media (LB medium, Beef extract peptone, MRS medium and LBS medium). [Results] Twenty-two different bacterial strains were isolated from the guts of C. japonicus. These belonged to 17 genera of the Firmicutes, Actinobacteria and Proteobacterium. Four kinds of culture mediums had high selectivity, and isolated different bacterial species. More bacterial species were isolated from LB and beef extract peptone medium (10 and 8 species respectively), less were isolated from LBS and MRS medium (3 and 1 species respectively). In addition, bacterial species isolated from the digestive tracts of major and minor workers differed, which may be related to their functions and responsibilities in the colony. Further research will be required to clarify this. [Conclusion] Several anaerobic bacteria were successfully isolated from the guts of C. japonicus using the Interlayer Petri Dish Method, which provides a reference for isolating the gut bacteria of other insects.%【目的】采用自行设置的厌氧装置,分离培养日本弓背蚁Camponotus japonicus消化道厌氧细菌。【方法】改进了一种简易的厌氧装置——平皿夹层法,利用4种培养基对日本弓背蚁消化道内厌氧或兼性厌氧菌进行分离培养。【结果】从日本弓背蚁消化道共分离到22个不同的菌株,隶属于厚壁菌门、放线菌门和变形菌门3大类群的17个属;4种培养基分离到的细菌种类存在明显差异,选择性较强,其中从LB和牛肉膏蛋白胨培养基上分离到的细菌种类较多,分别为10种和8种;从MRS和LBS培养基上分离到的细菌较少,分别为3种和1种;大工蚁和小工蚁的消化道细

  19. Anaerobic degradation and toxicity of commercial cationic surfactants in anaerobic screening tests. (United States)

    García, M T; Campos, E; Sánchez-Leal, J; Ribosa, I


    Anaerobic biodegradability and toxicity on anaerobic bacteria of di(hydrogenated tallow) dimethyl ammonium chloride (DHTDMAC) and two esterquats have been investigated. A batch test system containing municipal digester solids as a source of anaerobic bacteria, based on the method proposed by the ECETOC, has been applied. To evaluate the potential toxicity of such surfactants on anaerobic sludge, a co-substrate, an easily biodegradable compound in anaerobic conditions, has been added to the samples to test and the effects on biogas production have been determined. For the esterquats studied high biodegradation levels were obtained and no toxic effects on anaerobic bacteria were observed even at the highest concentrations tested, 100 and 200 mg C/l, respectively. On the contrary, DHTDMAC was not degradated at the same test conditions. However, no inhibitory effects on the biogas production were detected for this surfactant at concentrations <100 mg C/l.

  20. Comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin and the Hawaiian marine algae, Chaetoceros, for potential broad-spectrum control of anaerobically grown lactic acid bacteria (United States)

    The gastrointestinal tract of bovines often contains bacteria that contribute to disorders of the rumen and may also contain foodborne or opportunistic human pathogens as well as bacteria capable of causing mastitis in cows. Thus, there is a need to develop broad-spectrum therapies that are effecti...

  1. Development of a Laboratory Model of a Phototroph-Heterotroph Mixed-Species Biofilm at the Stone/Air Interface. (United States)

    Villa, Federica; Pitts, Betsey; Lauchnor, Ellen; Cappitelli, Francesca; Stewart, Philip S


    Recent scientific investigations have shed light on the ecological importance and physiological complexity of subaerial biofilms (SABs) inhabiting lithic surfaces. In the field of sustainable cultural heritage (CH) preservation, mechanistic approaches aimed at investigation of the spatiotemporal patterns of interactions between the biofilm, the stone, and the atmosphere are of outstanding importance. However, these interactions have proven difficult to explore with field experiments due to the inaccessibility of samples, the complexity of the ecosystem under investigation and the temporal resolution of the experiments. To overcome these limitations, we aimed at developing a unifying methodology to reproduce a fast-growing, phototroph-heterotroph mixed species biofilm at the stone/air interface. Our experiments underscore the ability of the dual-species SAB model to capture functional traits characteristic of biofilms inhabiting lithic substrate such as: (i) microcolonies of aggregated bacteria; (ii) network like structure following surface topography; (iii) cooperation between phototrophs and heterotrophs and cross feeding processes; (iv) ability to change the chemical parameters that characterize the microhabitats; (v) survival under desiccation and (vi) biocide tolerance. With its advantages in control, replication, range of different experimental scenarios and matches with the real ecosystem, the developed model system is a powerful tool to advance our mechanistic understanding of the stone-biofilm-atmosphere interplay in different environments.

  2. Development of a laboratory model of a phototroph-heterotroph mixed-species biofilm at the stone/air interface

    Directory of Open Access Journals (Sweden)

    Federica eVilla


    Full Text Available Recent scientific investigations have shed light on the ecological importance and physiological complexity of subaerial biofilms (SABs inhabiting lithic surfaces. In the field of sustainable cultural heritage (CH preservation, mechanistic approaches aimed at investigation of the spatiotemporal patterns of interactions between the biofilm, the stone, and the atmosphere are of outstanding importance. However, these interactions have proven difficult to explore with field experiments due to the inaccessibility of samples, the complexity of the ecosystem under investigation and the temporal resolution of the experiments.To overcome these limitations, we aimed at developing a unifying methodology to reproduce a fast-growing, phototroph-heterotroph mixed species biofilm at the stone/air interface. Our experiments underscore the ability of the dual-species SAB model to capture functional traits characteristic of biofilms inhabiting lithic substrate such as: i microcolonies of aggregated bacteria; ii network like structure following surface topography; iii cooperation between phototrophs and heterotrophs and cross feeding processes; iv ability to change the chemical parameters that characterize the microhabitats; v survival under desiccation and vi biocide tolerance. With its advantages in control, replication, range of different experimental scenarios and matches with the real ecosystem, the developed model system is a powerful tool to advance our mechanistic understanding of the stone-biofilm-atmosphere interplay in different environments.

  3. Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth. (United States)

    Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen


    An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110 nm or 200 nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200 nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration.

  4. Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival (United States)

    Duanmu, Deqiang; Casero, David; Dent, Rachel M.; Gallaher, Sean; Yang, Wenqiang; Rockwell, Nathan C.; Martin, Shelley S.; Pellegrini, Matteo; Niyogi, Krishna K.; Merchant, Sabeeha S.; Grossman, Arthur R.; Lagarias, J. Clark


    The maintenance of functional chloroplasts in photosynthetic eukaryotes requires real-time coordination of the nuclear and plastid genomes. Tetrapyrroles play a significant role in plastid-to-nucleus retrograde signaling in plants to ensure that nuclear gene expression is attuned to the needs of the chloroplast. Well-known sites of synthesis of chlorophyll for photosynthesis, plant chloroplasts also export heme and heme-derived linear tetrapyrroles (bilins), two critical metabolites respectively required for essential cellular activities and for light sensing by phytochromes. Here we establish that Chlamydomonas reinhardtii, one of many chlorophyte species that lack phytochromes, can synthesize bilins in both plastid and cytosol compartments. Genetic analyses show that both pathways contribute to iron acquisition from extracellular heme, whereas the plastid-localized pathway is essential for light-dependent greening and phototrophic growth. Our discovery of a bilin-dependent nuclear gene network implicates a widespread use of bilins as retrograde signals in oxygenic photosynthetic species. Our studies also suggest that bilins trigger critical metabolic pathways to detoxify molecular oxygen produced by photosynthesis, thereby permitting survival and phototrophic growth during the light period. PMID:23345435

  5. Simple and Versatile Turbidimetric Monitoring of Bacterial Growth in Liquid Cultures Using a Customized 3D Printed Culture Tube Holder and a Miniaturized Spectrophotometer: Application to Facultative and Strictly Anaerobic Bacteria (United States)

    Maia, Margarida R. G.; Marques, Sara; Cabrita, Ana R. J.; Wallace, R. John; Thompson, Gertrude; Fonseca, António J. M.; Oliveira, Hugo M.


    Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213) and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897) anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256). For the strictly anaerobic species, a high precision (relative standard deviation < 3.5%) was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells. PMID:27630632

  6. Simple and versatile turbidimetric monitoring of bacterial growth in liquid cultures using a customized 3D printed culture tube holder and a miniaturized spectrophotometer: application to facultative and strictly anaerobic bacteria

    Directory of Open Access Journals (Sweden)

    Margarida R. G. Maia


    Full Text Available Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213 and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897 anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256. For the strictly anaerobic species, a high precision (RSD < 3.5% was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells.

  7. Simple and Versatile Turbidimetric Monitoring of Bacterial Growth in Liquid Cultures Using a Customized 3D Printed Culture Tube Holder and a Miniaturized Spectrophotometer: Application to Facultative and Strictly Anaerobic Bacteria. (United States)

    Maia, Margarida R G; Marques, Sara; Cabrita, Ana R J; Wallace, R John; Thompson, Gertrude; Fonseca, António J M; Oliveira, Hugo M


    Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213) and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897) anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256). For the strictly anaerobic species, a high precision (relative standard deviation < 3.5%) was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells.

  8. Phototrophic microorganisms in biofilm samples from Vernjika Cave, Serbia (United States)

    Popović, Slađana; Jovanović, Jelena; Predojević, Dragana; Trbojević, Ivana; Blagojević, Ana; Subakov Simić, Gordana


    Caves represent specific natural monuments in terms of structure, complexity and beauty which can be found worldwide. Even though they are considered extreme environments, they are still a unique habitat for a large number of organisms that grow and proliferate here. Often can be seen that the cave walls are differently coloured as a consequence of the biofilm development. Biofilms represent complex communities of microorganisms that can develop on different kind of surfaces, including various rock surfaces. Each microbe species play a different role in a community, but their development on stone surfaces can cause substantial damage to the substrates through different mechanisms of biodeterioration and degradation. There is an increased interest in the phototrophic component of biofilms (aerophytic cyanobacteria and algae), especially cyanobacteria, an ancient microorganisms capable to survive the most diverse extreme conditions. These phototrophs can easily be found at cave entrances illuminated by direct or indirect sunlight and areas near artificial lights. Cyanobacteria and algae were investigated in biofilm samples taken from the entrance of Vernjika Cave in Eastern Serbia. Cyanobacteria, Chlorophyta and Bacillariophyta were documented, with Cyanobacteria as a group with the highest number of recorded taxa. Chroococcalean species were the most diverse with the most frequently encountered species from the genus Gloeocapsa. Phormidium and Nostoc species were commonly recorded Oscillatoriales and Nostocles, respectively. Among Oscillatoriales species, it was noticed that one Phormidium species precipitates CaCO3 on it's sheats. Trebouxia sp. and Desmococcus olivaceus were frequently documented Chlorophyta, and representatives of Bacillariophyta were exclusively aerophytic taxa, mostly belonging to the genera Luticola and Humidophila. Measured ecological parameters, temperature and relative humidity, were influenced by the external climatic changes, while light

  9. 液相条件下低温常压 DBD 等离子对厌氧细菌的杀灭研究%Study on Anaerobic Bacteria Sterilization by Low Temperature Atmospheric DBD Plasma in Liquid Phase

    Institute of Scientific and Technical Information of China (English)

    杨博; 郭斯青; 郭荣; 陈欢欢; 谢博厚


    The rules of Anaerobic Bacteria Lactobacillus acidophilus sterilization by Low Temperature Atmospheric DBD was studied , in terms of plasma voltage , plasma current and exposure time.It was indicated that there was a linear dependent between plasma parameters and sterilization capacity , and Leakage of cellular protein and DNA was also observed during initial treatment stage of plasma exposure by UV-visible spectrophotometer examination , which meant the bacteria activity was reduced successfully.%采用低温常压DBD等离子灭菌技术,研究了不同等离子体放电参数(电压、电流及放电时间等)对液相中乳酸杆菌的杀灭影响规律。研究发现,等离子体杀灭液相中乳酸杆菌的能力与其放电参数线性相关;紫外可见吸收光谱检测发现等离子体处理初期细胞蛋白质和DNA已经开始泄漏,细菌活性被有效削减。

  10. Evaluation of surface contamination of bacteria in various dental clinics with special reference to obligate and facultative anaerobic spore bearing bacilli

    Directory of Open Access Journals (Sweden)

    Kannan I, Jessica Yolanda Jeevitha, Sambandam Cecilia, Jayalakshmi M, Premavathy RK and Shantha S


    Full Text Available Introduction: The occupational health and safety is an important prerequisite in dental clinic setup for well being of both the doctor and patient. Both the patient and dentist are always at the risk of infections. Aim and objectives: There is no proper literature on the survey of bacterial spores, especially of Clostridium species in dental clinics. Hence an attempt has been made in the present pilot study to evaluate the surface contamination with special reference to bacterial spores. Materials and methods: Various dental clinics from Chennai city, India were selected for the present study. Samples were collected from two clinics each from endodontic, prosthodontic, orthodontic, and periodontic. In each clinic important places were selected for sampling. The samples were collected in the form of swabs. The swabs thus obtained were inoculated into Robertson Cooked Meat Medium and was incubated in anaerobic condition at 370C for 7 days. Each day the tubes were examined for turbidity and colour change and were noted. At the end of 7th day the smear was prepared from each tube and gram staining was performed. The gram stained slides were examined microscopically for the presence of spore bearing bacilli especially with special reference to terminal spore bearing bacilli. Results and conclusion: From the present study it is clear that the dental clinics invariably posses a lot of aerobic and anaerobic spores irrespective of stringent disinfection procedures. Hence it is mandatory for the dental clinics to undergo periodical microbiological surveillance and to take proper steps in the control of bacterial spores.

  11. Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    M.T. Kato


    Full Text Available The anaerobic treatment processes are considered to be well-established methods for the elimination of easily biodegradable organic matter from wastewaters. Some difficulties concerning certain wastewaters are related to the possible presence of dissolved oxygen. The common belief is that anaerobes are oxygen intolerant. Therefore, the common practice is to use sequencing anaerobic and aerobic steps in separate tanks. Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. Previous experiments with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges was quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of new applications in wastewater treatment

  12. Diversity and distribution in hypersaline microbial mats of bacteria related to Chloroflexus spp

    DEFF Research Database (Denmark)

    Nübel, Ulrich; Bateson, Mary M.; Madigan, Michael T.;


    primers for the specific amplification of 16S rRNA genes from filamentous phototrophic bacteria within the kingdom of "green nonsulfur bacteria." PCR products recovered from microbial mats in a saltern in Guerrero Negro, Mexico, were subjected to cloning or denaturing gradient gel electrophoresis...

  13. Quantitative fluorescent in-situ hybridization: a hypothesized competition mode between two dominant bacteria groups in hydrogen-producing anaerobic sludge processes. (United States)

    Huang, C-L; Chen, C-C; Lin, C-Y; Liu, W-T


    Two hydrogen-producing continuous flow stirred tank reactors (CSTRs) fed respectively with glucose and sucrose were investigated by polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE) and fluorescent in-situ hybridization (FISH). The substrate was fed in a continuous mode decreased from hydraulic retention time (HRT) 10 hours to 6, 5, 4, 3, and 2 hours. Quantitative fluorescent in-situ hybridization (FISH) observations further demonstrated that two morphotypes of bacteria dominated both microbial communities. One was long rod bacteria which can be targeted either by Chis150 probe designed to hybridize the gram positive low G + C bacteria or the specific oligonucleotide probe Lg10-6. The probe Lg10-6, affiliated with Clostridium pasteurianum, was designed and then checked with other reference organisms. The other type, unknown group, which cannot be detected by Chis150 was curved rod bacteria. Notably, the population ratios of the two predominant groups reflected the different operational performance of the two reactors, such as hydrogen producing rates, substrate turnover rates and metabolites compositions. Therefore, a competition mode of the two dominant bacteria groups was hypothesized. In the study, 16S rRNA-based gene library of hydrogen-producing microbial communities was established. The efficiency of hydrogen yields was correlated with substrates (glucose or sucrose), HRT, metabolites compositions (acetate, propionate, butyrate and ethanol), thermal pre-treatment (seed biomass was heated at 100 degrees C for 45 minutes), and microbial communities in the bioreactor, not sludge sources (municipal sewage sludge, alcohol-processing sludge, or bean-processing sludge). The designed specific oligonucleotide probe Lg10-6 also provides us a useful and fast molecular tool to screen hydrogen-producing microbial communities in the future research.

  14. 血清IgG抗体含量与口腔厌氧菌致牙髓感染的关系%Relationship between contents of serum IgG antibody and pulp infections caused by oral anaerobic bacteria

    Institute of Scientific and Technical Information of China (English)

    吕朋君; 马珅; 刘晓斌


    OBJECTIVE To observe the relationship between the level of serum IgG antibody and the pulp infections caused by oral anaerobic bacteria by referring to the characteristics of specific response between antigen and anti‐body so as to reduce the infection rate .METHODS The patients with pulp diseases who were treated in the hospi‐tal from Jan 2013 to Jan 2014 were enrolled in the study and divided into the group B ,C ,and D ,with 10 cases in each ;meanwhile 10 healthy subjects were chosen as the group A .The IgG antibody contents in the 10 internation‐al standard anaerobic bacteria strains isolated from the serum of the patients with infections and the healthy sub‐jects were determined by using ELISA method ,the relationship between the pulp infections and the oral anaerobic bacteria was specifically analyzed ,and the statistical analysis of data was performed with the use of SPSS 17 .0 software .RESULTS The average level of serum antibody in Prevotella intermedia was significantly lower in the group A than in the group B ,C ,and D (P<0 .05) .As compared with the group A ,the OD values of other three groups were more than 2 .1 ,and all were positive .There was significant difference in the average level of serum antibody in Porphyromonas gingivalis among the healthy subjects ,the patients with pulp infections ,and the pa‐tients with pulp‐periodontal diseases (P<0 .05) ,as compared with the patients with periodontal disease ,howev‐er ,the difference was not significant .There was no significant difference in the OD value of serum antibody in the anaerobic bacteria among the four groups .CONCLUSION The ELISA ,as is applied for the analysis of the anaero‐bic bacteria causing the pulp infections ,may contribute to considerably higher isolation rate and accuracy than the traditional microbial culture ,and it can be used as a conventional method for the detection of pathogenic bacteria causing pulp infections .%目的:利用抗原与抗体特异反应的

  15. 口腔需氧菌及兼性厌氧菌种分离鉴定系统的建立%Isolation and identification of aerobic and facultative anaerobic bacteria in the oral cavity

    Institute of Scientific and Technical Information of China (English)

    陆文昕; 肖丽英; 李燕; 吴凡子; 周辛璇; 吴岚; 李明云; 任彪; 郭强; 黄睿洁; 李继遥


    目的:建立口腔需氧菌和兼性菌的系统分离鉴定方法。方法招募20名口腔健康志愿者及8名口腔疾病患者,分别采集唾液、龈下菌斑、龈上菌斑和根尖周肉芽样本,采用形态鉴定、全自动生化鉴定仪及16s rRNA基因测序的多相分类方法,对口腔可培养细菌进行分离鉴定。结果鉴定出口腔菌种63种,共175株,梅里埃生化鉴定与16s rRNA基因鉴定的符合度为22.39%,不符合的菌种以基因测序结果为准。链球菌属、放线菌属和葡萄球菌属检出率占前3位,菌种以咽峡炎链球菌、口腔放线菌、变异链球菌、缓症链球菌检出频率最高。慢性根尖周炎的咽峡炎链球菌检出率最高;放射性龋患者中,中间链球菌、金黄色葡萄球菌检出率较高;猛性龋患者中,变异链球菌远高于其他细菌。结论口腔需氧菌和兼性厌氧菌中以革兰阳性菌检出率最高。对于口腔细菌鉴定来说,梅里埃生化鉴定仪鉴定准确率不高,但可提供菌株生理生化指标,而全长的16s rRNA基因测序鉴定更为可靠。%Objective To establish a systematic method for isolation and identification of aerobic and facultative anaerobic bacteria in the oral cavity. Methods Samples of the saliva, dental plaque and periapical granulation tissue were collected from 20 subjects with healthy oral condition and from 8 patients with different oral diseases. The bacteria in the samples were identified by morphological identification, VITEK automatic microorganism identification and 16s rRNA gene sequencing. Results VITEK automatic microorganism identification and 16s rRNA gene sequencing showed an agreement rate of 22.39%in identifying the bacteria in the samples. We identified altogether 63 bacterial genus (175 species), among which Streptococcus, Actinomyces and Staphylococcus were the most common bacterial genus, and Streptococcus anginosus, Actinomyces oris, Streptococcus mutans

  16. The potential of bacteria isolated from ruminal contents of seaweed-eating North Ronaldsay sheep to hydrolyse seaweed components and produce methane by anaerobic digestion in vitro. (United States)

    Williams, Allan G; Withers, Susan; Sutherland, Alastair D


    The production of methane biofuel from seaweeds is limited by the hydrolysis of polysaccharides. The rumen microbiota of seaweed-eating North Ronaldsay sheep was studied for polysaccharidic bacterial isolates degrading brown-seaweed polysaccharides. Only nine isolates out of 65 utilized >90% of the polysaccharide they were isolated on. The nine isolates (eight Prevotella spp. and one Clostridium butyricum) utilized whole Laminaria hyperborea extract and a range of seaweed polysaccharides, including alginate (seven out of nine isolates), laminarin and carboxymethylcellulose (eight out of nine isolates); while two out of nine isolates additionally hydrolysed fucoidan to some extent. Crude enzyme extracts from three of the isolates studied further had diverse glycosidases and polysaccharidase activities; particularly against laminarin and alginate (two isolates were shown to have alginate lyase activity) and notably fucoidan and carageenan (one isolate). In serial culture rumen microbiota hydrolysed a range of seaweed polysaccharides (fucoidan to a notably lesser degree) and homogenates of L. hyperborea, mixed Fucus spp. and Ascophyllum nodosum to produce methane and acetate. The rumen microbiota and isolates represent potential adjunct organisms or enzymes which may improve hydrolysis of seaweed components and thus improve the efficiency of seaweed anaerobic digestion for methane biofuel production.

  17. Spectral light measurements in microbenthic phototrophic communities with a fiber-optic microprobe coupled to a sensitive diode array detector

    Energy Technology Data Exchange (ETDEWEB)

    Kuehl, M. (Univ. of Aarhus (Denmark)); Joergensen, B.B. (Max-Planck-Inst. for Marine Microbiology, Bremen (Germany))


    A diode array detector system for microscale light measurements with fiber-optic microprobes was developed; it measures intensities of 400-900-nm light over >6 orders of magnitude with a spectral resolution of 2-5 nm. Fiber-optic microprobes to measure field radiance or scalar irradiance were coupled to the detector system and used for spectral light measurements in hypersaline microbial mats and in laminated phototrophic communities of coastal sediments. The vertical distribution of major photopigments of microalgae, cyanobacteria, and anoxygenic phototrophic bacteria could be identified from extinction maxima in measured radiance spectra at 430-550 nm (Chl a and carotenoids), 620-625 nm (phycocyanin), 675 nm (Chl a), 745-750 nm (BChl c), 800-810 nm, and 860-880 nm (BChl a). Scalar irradiance spectra exhibited a different spectral composition and a higher light intensity at the sediment surface as compared to incident light. IR light thus reached 200% of incident at the sediment surface. Maximal light penetration was found for IR light, whereas visible light was strongly attenuated in the upper 0-2 mm of the sediment. Measurements of photon scalar irradiance (400-700 nm) were combined with microelectrode measurements of oxygenic photosynthesis in the coastal sediment. With an incident light intensity of 200 [mu]Einst m[sup [minus]2]s[sup [minus]1], photon scalar irradiance reached a maximum of 283 [mu]Einst m[sup [minus]2]s[sup [minus]1] at the sediment surface. The lower boundary of the euphotic zone was 2.2 mm below the surface at a light intensity of 12 [mu]Einst m[sup [minus]2]s[sup [minus]1]. 20 refs., 6 figs.

  18. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini


    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens...

  19. Mushroom speleothems: Stromatolites that formed in the absence of phototrophs

    Directory of Open Access Journals (Sweden)

    Tomaso eBontognali


    Full Text Available Unusual speleothems resembling giant mushrooms occur in Santa Catalina Cave, Cuba. Although these mineral buildups are considered a natural heritage, their composition and formation mechanism remain poorly understood. Here we characterize their morphology and mineralogy and present a model for their genesis. We propose that the mushrooms, which are mainly comprised of calcite and aragonite, formed during four different phases within an evolving cave environment. The stipe of the mushroom is an assemblage of three well-known speleothems: a stalagmite surrounded by calcite rafts that were subsequently encrusted by cave clouds (mammilaries. More peculiar is the cap of the mushroom, which is morphologically similar to cerebroid stromatolites and thrombolites of microbial origin occurring in marine environments. Scanning electron microscopy investigations of this last unit revealed the presence of fossilized extracellular polymeric substances (EPS – the constituents of biofilms and microbial mats. These organic microstructures are mineralized with Ca-carbonate, suggesting that the mushroom cap formed through a microbially-influenced mineralization process. The existence of cerebroid Ca-carbonate buildups forming in dark caves (i.e., in the absence of phototrophs has interesting implications for the study of fossil microbialites preserved in ancient rocks, which are today considered as one of the earliest evidence for life on Earth.

  20. Cultivation of Isochrysis galbana in phototrophic, heterotrophic, and mixotrophic conditions. (United States)

    Alkhamis, Yousef; Qin, Jian G


    This study compared the growth and biomass production of Isochrysis galbana under hetero-, mixo-, and phototrophic conditions using different organic carbon sources. The growth of I. galbana was inhibited in heterotrophy but was enhanced in mixotrophy compared to that in phototrophy. Subsequently, the influences of organic carbon and environmental factors (light and salinity) on the growth of I. galbana were further investigated. Algal dry weight increased as glycerol concentrations increased from 0 to 200 mmol and the highest algal production occurred at 50 mmol glycerol. At a range of light intensities of 25-200 μ mol photons m(-2) s(-2), the highest algal growth rate occurred at 100 photons μ mol m(-2) s(-2). The growth of I. galbana was significantly affected by photoperiod, and the maximal dry weight was obtained at 12 h light and 12 h dark. In the salinity test, I. galbana could grow in a wide range of salinities from 10 to 65 ‰, but the 35 ‰ salinity was optimal. This study suggests that the growth and production of I. galbana can be improved using mixotrophic culture at 50 mmol glycerol in 35 ‰ salinity.

  1. Mushroom speleothems: Stromatolites that formed in the absence of phototrophs (United States)

    Bontognali, Tomaso; D'Angeli, Ilenia; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano; Gonzales, Esteban; DeWaele, Jo


    Unusual speleothems resembling giant mushrooms occur in Santa Catalina Cave, Cuba. Although these mineral buildups are considered a natural heritage, their composition and formation mechanism remain poorly understood. Here we characterize their morphology and mineralogy and present a model for their genesis. We propose that the mushrooms, which are mainly comprised of calcite and aragonite, formed during four different phases within an evolving cave environment. The stipe of the mushroom is an assemblage of three well-known speleothems: a stalagmite surrounded by calcite rafts that were subsequently encrusted by cave clouds (mammilaries). More peculiar is the cap of the mushroom, which is morphologically similar to cerebroid stromatolites and thrombolites of microbial origin occurring in marine environments. Scanning electron microscopy investigations of this last unit revealed the presence of fossilized extracellular polymeric substances (EPS) - the constituents of biofilms and microbial mats. These organic microstructures are mineralized with Ca-carbonate, suggesting that the mushroom cap formed through a microbially-influenced mineralization process. The existence of cerebroid Ca-carbonate buildups forming in dark caves (i.e., in the absence of phototrophs) has interesting implications for the study of fossil microbialites preserved in ancient rocks, which are today considered as one of the earliest evidence for life on Earth.

  2. Anaerobic Metabolism and Bioremediation of Explosives-Contaminated Soil (United States)

    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.

  3. An investigation into the removal of Salmonella and enteric indicator bacteria from the separated liquid fraction of raw or anaerobically digested pig manure using novel on-farm woodchip biofilters. (United States)

    McCarthy, G; Lawlor, P G; Carney, K N; Zhan, X; Gutierrez, M; Gardiner, G E


    The objective was to investigate the removal of Salmonella and enteric indicator bacteria from the liquid fraction of raw and anaerobically digested (AD) pig manure in woodchip biofilters over a 14 week (98 day) period. Antibiotic susceptible Salmonella Infantis was detected in one influent material (liquid fraction of raw manure) on two occasions but was not found in the effluent at any time point. Furthermore, mean coliform reductions of 56% were observed in the biofilters treating the liquid fraction of raw manure. However, a mean increase of 228% was found in those treating the liquid from AD manure, despite the fact that the microbial challenge to these biofilters was lower. In addition, relatively high coliform counts were still present in the effluent from both biofilter treatments, especially in the systems treating the liquid fraction of AD manure. However, findings for Escherichia coli and Enterococcus were more promising, with reductions observed for both treatments (10 and 18.5% for E. coli and 71 and 87% for Enterococcus). Moreover, E. coli and Enterococcus were at, or just above, the limit of detection in the final effluents. Overall, although, there are no microbial limits for discharge or washwaters, the woodchip filter effluent would appear safe for discharge to waterways or use on-farm as regards Salmonella, E. coli and Enterococcus but not coliform. In conclusion, woodchip biofilters offer potential as a low-cost sustainable novel treatment option for the removal of pathogens from the liquid fraction of pig manure.

  4. 硫酸盐还原菌及其在废水厌氧治理中的应用%Application of sulfate-reducing bacteria to anaerobic wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    肖利萍; 张镭; 李月


    硫酸盐还原菌(SRB)在废水处理方面有独特的优势,在厌氧环境中能以硫酸盐作为电子受体降解有机污染物.本文阐明了SRB处理废水中污染物的机理,综述了国内外利用SRB处理重金属离子废水、含硫酸盐有机废水和酸性矿山废水的研究进展.最后总结了目前在工程应用方面尚存在的问题.%Sulfate reducing bacteria (SRB) has unique advantage in wastewater treatment and can degrade organic pollutants with sulfate as electron acceptor in the anaerobic environment. This paper introduced the SRB mechanism for wastewater treatment, summarized the applications of SRB on the treatment of heavy metal wastewater , organic wastewater containing sulfate and acid mine wastewater at home and abroad. At last, the current problems in engineering application are explained.

  5. Genome-enabled studies of anaerobic, nitrate-dependent iron oxidation in the chemolithoautotrophic bacterium Thiobacillus denitrificans

    Directory of Open Access Journals (Sweden)

    Harry R Beller


    Full Text Available Thiobacillus denitrificans is a chemolithoautotrophic bacterium capable of anaerobic, nitrate-dependent U(IV and Fe(II oxidation, both of which can strongly influence the long-term efficacy of in situ reductive immobilization of uranium in contaminated aquifers. We previously identified two c-type cytochromes involved in nitrate-dependent U(IV oxidation in T. denitrificans and hypothesized that c-type cytochromes would also catalyze Fe(II oxidation, as they have been found to play this role in anaerobic phototrophic Fe(II-oxidizing bacteria. Here we report on efforts to identify genes associated with nitrate-dependent Fe(II oxidation, namely (a whole-genome transcriptional studies [using FeCO3, Fe2+, and U(IV oxides as electron donors under denitrifying conditions], (b Fe(II oxidation assays performed with knockout mutants targeting primarily highly expressed or upregulated c-type cytochromes, and (c random transposon-mutagenesis studies with screening for Fe(II oxidation. Assays of mutants for 26 target genes, most of which were c-type cytochromes, indicated that none of the mutants tested were significantly defective in nitrate-dependent Fe(II oxidation. The non-defective mutants included the c1-cytochrome subunit of the cytochrome bc1 complex (complex III, which has relevance to a previously proposed role for this complex in nitrate-dependent Fe(II oxidation and to current concepts of reverse electron transfer. A transposon mutant with a disrupted gene associated with NADH:ubiquinone oxidoreductase (complex I was ~35% defective relative to the wild-type strain; this strain was similarly defective in nitrate reduction with thiosulfate as the electron donor. Overall, our results indicate that nitrate-dependent Fe(II oxidation in T. denitrificans is not catalyzed by the same c-type cytochromes involved in U(IV oxidation, nor have other c-type cytochromes yet been implicated in the process.

  6. Direct identification of bacteria from BacT/ALERT anaerobic positive blood cultures by MALDI-TOF MS: MALDI Sepsityper kit versus an in-house saponin method for bacterial extraction. (United States)

    Meex, Cécile; Neuville, Florence; Descy, Julie; Huynen, Pascale; Hayette, Marie-Pierre; De Mol, Patrick; Melin, Pierrette


    In cases of bacteraemia, a rapid species identification of the causal agent directly from positive blood culture broths could assist clinicians in the timely targeting of empirical antimicrobial therapy. For this purpose, we evaluated the direct identification of micro-organisms from BacT/ALERT (bioMérieux) anaerobic positive blood cultures without charcoal using the Microflex matrix-assisted laser desorption/ionization (MALDI) time of flight MS (Bruker), after bacterial extraction by using two different methods: the MALDI Sepsityper kit (Bruker) and an in-house saponin lysis method. Bruker's recommended criteria for identification were expanded in this study, with acceptance of the species identification when the first three results with the best matches with the MALDI Biotyper database were identical, whatever the scores were. In total, 107 monobacterial cultures and six polymicrobial cultures from 77 different patients were included in this study. Among monomicrobial cultures, we identified up to the species level 67 and 66 % of bacteria with the MALDI Sepsityper kit and the saponin method, respectively. There was no significant difference between the two extraction methods. The direct species identification was particularly inconclusive for Gram-positive bacteria, as only 58 and 52 % of them were identified to the species level with the MALDI Sepsityper kit and the saponin method, respectively. Results for Gram-negative bacilli were better, with 82.5 and 90 % of correct identification to the species level with the MALDI Sepsityper kit and the saponin method, respectively. No misidentifications were given by the direct procedures when compared with identifications provided by the conventional method. Concerning the six polymicrobial blood cultures, whatever the extraction method used, a correct direct identification was only provided for one of the isolated bacteria on solid medium in all cases. The analysis of the time-to-result demonstrated a reduction

  7. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini


    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  8. Novel acsF gene primers revealed a diverse phototrophic bacterial population, including Gemmatimonadetes, in Lake Taihu (China)

    DEFF Research Database (Denmark)

    Huang, Yili; Zeng, Yanhua; Lu, Hang;


    UNLABELLED: Anoxygenic phototrophs represent an environmentally important and phylogenetically diverse group of organisms. They harvest light using bacteriochlorophyll-containing reaction centers. Recently, a novel phototrophic bacterium, Gemmatimonas phototrophica, belonging to a rarely studied ...

  9. Environmental control of growth and BChl a expression in an aerobic anoxygenic phototrophic bacterium,Erythrobacter longus (DSMZ6997)

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; JIAO Nianzhi; PENG Zaiqing


    Aerobic anoxygenic phototrophic bacteria (AAPB), which form a unique functional group of heterotrophic bacteria, have the ability to utilize light energy. The impact of carbon source and light intensity on the growth and bacteriochlorophyll a (BChl a) expression of a typical strain of AAPB, Erythrobacter longus strain DSMZ6997 was examined during batch culture and continuous culture. The results showed that the expression of BChl a in DSMZ6997 was regulated by both carbon-source and light conditions, and was stimulated by low availability of carbon but inhibited by light to a certain extent at 300 lx and completely at 1 500 lx. In contrast, cell abundance, and even cell size of this strain, was substantially enhanced under light/dark cycle cultivation conditions over dark conditions, indicating the promotion of growth by light. These results led to the conclusion that utilization of light through BChl a helps AAPB to survive under carbon stress, while light at high intensity is harmful to the synthesis of BChl a in AAPB.

  10. Enumeração e isolamento de bactérias anaeróbias facultativas num reator de fluxo ascendente e manta de lodo tratando efluente de uma indústria de gelatina - DOI: 10.4025/actascibiolsci.v25i2.1977 Enumeration and isolation of facultative anaerobic bacteria in an upflow anaerobic sludge blanket reactor treating wastewater from a gelatine industry- DOI: 10.4025/actascibiolsci.v25i2.1977

    Directory of Open Access Journals (Sweden)

    Celso Vataru Nakamura


    Full Text Available Neste trabalho foram determinados os níveis de bactérias anaeróbias facultativas em Reator de Fluxo Ascendente e Manta de Lodo (UASB utilizado no tratamento de efluente de industria de gelatina. A quantificação dos microrganismos apresentou similar valor na manta de lodo granular e na zona de fluidização. No compartimento de sedimentação do reator as bactérias foram dois logs menores. Estas comunidades são compostas principalmente de bacilos Gram-negativos. Os mais abundantes gêneros foram Acinetobacter, Aeromonas, Citrobacter, Escherichia, Klebsiella e Stenotrophomonas. O significado para a saúde pública das bactérias isoladas no reator UASB é desconhecido. Algumas espécies são residentes permanentes, outras são encontradas em somente uma parte da população, e ainda outras espécies são patógenos oportunistas que causam infecção humana. No presente estudo, nenhuma das bactérias predominantes pertence ao grupo dos patógenos estritosThis experiment measured levels of facultative anaerobic bacteria in an Upflow Anaerobic Sludge Blanket (UASB reactor treating wastewater from a gelatin industry. The microorganism quantification showed similar values in granular sludge bed and fluidized zone. In the settling compartment of reactor, the bacteria were two logs lower. These communities are composed mainly of Gram-negative rods. The most abundant genera isolated were Acinetobacter, Aeromonas, Citrobacter, Escherichia, Klebsiella and Stenotrophomonas. The significance of the bacteria isolated from UASB reactor for public health is unknown. Some species are permanent residents; other are found only in a fraction of the population, and still other species are opportunistic pathogens that cause human infections. In the present study, none of the predominant bacteria belonged to the group of strict pathogens

  11. Competition for inorganic carbon between oxygenic and anoxygenic phototrophs in a hypersaline microbial mat, Guerrero Negro, Mexico

    DEFF Research Database (Denmark)

    Finke, Niko; Hoehler, Tori M.; Polerecky, Lubos


    While most oxygenic phototrophs harvest light only in the visible range (400-700 nm, VIS), anoxygenic phototrophs can harvest near infrared light (> 700 nm, NIR). To study interactions between the photosynthetic guilds we used microsensors to measure oxygen and gross oxygenic photosynthesis (gOP)...

  12. Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography (United States)

    Palmisano, A. C.; Cronin, S. E.; Des Marais, D. J.


    As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program. Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms. Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs. Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments. This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

  13. Bacteria Provide Cleanup of Oil Spills, Wastewater (United States)


    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  14. Biosynthesis and Isotopic Composition of Bacteriochlorophyll a and Okenone in Purple Sulfur Bacteria (United States)

    Smith, D.; Scott, J. H.; Steele, A.; Cody, G. D.; Ohara, S.; Bowden, R.; Fogel, M. L.


    Phototrophic sulfur bacteria play an integral part in the anaerobic cycling of sulfur. Bacteriochloroyphll a (Bchl a) is a well-studied photosynthetic compound required for photosynthesis in the organisms that possess it. The only known fossil of purple sulfur bacteria (PSB) in the geologic record is okenane, believed to be of biologic origin originating from the carotenoid pigment okenone, which has only been documented in eleven species of Chromatiaceae. Organic geochemical studies have identified okenane in preserved organic matter in rocks and ancient sediments and further, okenone production has been observed in modern water columns and sediment surfaces. We have undertaken a comprehensive study on the biosynthesis of bacterial pigments including okenone and C, N, and S isotopic fractionation during various growth modes in controlled laboratory experiments of purple sulfur bacteria. Cultures of Marichromatium purpuratum 1591, M. purpuratum 1711, Thiocapsa marina 5653, and FGL21 (isolated from the chemocline of Fayetteville Green Lake, NY) were grown under autotrophic and photoheterotrophic (e.g. acetate or pyruvate) conditions in batch cultures. Concentrations of okenone and Bchl a were quantified as a function of time and growth by Ultra Performance-Liquid Chromatography-Mass Spectrometry (UP-LC-MS) and spectrophotometry. Overall okenone and Bchl a concentrations reached μM levels in the cultures. At stationary phase, all four strains achieved concentrations of okenone and Bchl a that were approximately 2.5 fM and 0.2 fM per cell, respectively, with okenone to Bchl a ratios of approximately 12 to 1. Isotope Ratio Mass Spectrometry (IRMS) was performed on bulk cells and compound specific analysis of Bchl a and okenone to better understand the fractionation associated with the production of the compounds.

  15. Ecophysiology of the anammox bacteria

    NARCIS (Netherlands)

    Kartal, Mustafa Boran


    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a cost-effecti

  16. Molecular AND logic gate based on bacterial anaerobic respiration. (United States)

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


    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.

  17. Description of a redox-controlled sulfidostat for the growth of sulfide-oxidizing phototrophs

    NARCIS (Netherlands)

    Sanchez, O; vanGemerden, H; Mas, J


    This paper describes a novel type of continuous culture for the growth of phototrophic sulfur oxidizers under constant concentrations of hydrogen sulfide, The culture maintains a constant concentration of sulfide despite possible variations in external factors likely to affect photosynthetic activit

  18. Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms. (United States)

    Paule, A; Roubeix, V; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L


    Ecotoxicological experiments have been performed in laboratory-scale microcosms to investigate the sensitivity of phototrophic biofilm communities to the alachlor herbicide, in relation to the stages of phototrophic biofilm maturation (age of the phototrophic biofilms) and physical structure (intact biofilm versus recolonization). The phototrophic biofilms were initially cultivated on artificial supports in a prototype rotating annular bioreactor (RAB) with Taylor-Couette type flow under constant operating conditions. Biofilms were collected after 1.6 and 4.4 weeks of culture providing biofilms with different maturation levels, and then exposed to nominal initial alachlor concentration of 10 μg L(-1) in either intact or recolonized biofilms for 15 days in microcosms (mean time-weighted average concentration - TWAC of 5.52 ± 0.74 μg L(-1)). At the end of the exposure period, alachlor effects were monitored by a combination of biomass descriptors (ash-free dry mass - AFDM, chlorophyll a), structural molecular fingerprinting (T-RFLP), carbon utilization spectra (Biolog) and diatom species composition. We found significant effects that in terms of AFDM, alachlor inhibited growth of the intact phototrophic biofilms. No effect of alachlor was observed on diatom composition or functional and structural properties of the bacterial community regardless of whether they were intact or recolonized. The intact three-dimensional structure of the biofilm did not appear to confer protection from the effects of alachlor. Bacterial community structure and biomass level of 4.4 weeks - intact phototrophic biofilms were significantly influenced by the biofilm maturation processes rather than alachlor exposure. The diatom communities which were largely composed of mobile and colonizer life-form populations were not affected by alachlor. This study showed that the effect of alachlor (at initial concentration of 10 μg L(-1) or mean TWAC of 5.52 ± 0.74 μg L(-1)) is mainly limited to

  19. A photosynthetic rotating annular bioreactor (Taylor-Couette type flow) for phototrophic biofilm cultures. (United States)

    Paule, A; Lauga, B; Ten-Hage, L; Morchain, J; Duran, R; Paul, E; Rols, J L


    In their natural environment, the structure and functioning of microbial communities from river phototrophic biofilms are driven by biotic and abiotic factors. An understanding of the mechanisms that mediate the community structure, its dynamics and the biological succession processes during phototrophic biofilm development can be gained using laboratory-scale systems operating with controlled parameters. For this purpose, we present the design and description of a new prototype of a rotating annular bioreactor (RAB) (Taylor-Couette type flow, liquid working volume of 5.04 L) specifically adapted for the cultivation and investigation of phototrophic biofilms. The innovation lies in the presence of a modular source of light inside of the system, with the biofilm colonization and development taking place on the stationary outer cylinder (onto 32 removable polyethylene plates). The biofilm cultures were investigated under controlled turbulent flowing conditions and nutrients were provided using a synthetic medium (tap water supplemented with nitrate, phosphate and silica) to favour the biofilm growth. The hydrodynamic features of the water flow were characterized using a tracer method, showing behaviour corresponding to a completely mixed reactor. Shear stress forces on the surface of plates were also quantified by computer simulations and correlated with the rotational speed of the inner cylinder. Two phototrophic biofilm development experiments were performed for periods of 6.7 and 7 weeks with different inoculation procedures and illumination intensities. For both experiments, biofilm biomasses exhibited linear growth kinetics and produced 4.2 and 2.4 mg cm(-)² of ash-free dry matter. Algal and bacterial community structures were assessed by microscopy and T-RFLP, respectively, and the two experiments were different but revealed similar temporal dynamics. Our study confirmed the performance and multipurpose nature of such an innovative photosynthetic bioreactor

  20. Rhodobacter megalophilus sp. nov., a phototroph from the Indian Himalayas possessing a wide temperature range for growth. (United States)

    Arunasri, K; Venkata Ramana, V; Spröer, C; Sasikala, Ch; Ramana, Ch V


    Two strains of phototrophic, purple non-sulfur bacteria capable of growing at low temperatures (5 degrees C) were isolated from the Himalayas. The two strains showed positive phototaxis and grew over a relatively wide temperature range (5-40 degrees C). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA194T clustered with members of the genus Rhodobacter. Strain JA194T showed highest 16S rRNA gene sequence similarity with Rhodobacter sphaeroides DSM 158T (99 %). However, DNA-DNA hybridization experiments between Rba. sphaeroides DSM 158T and strain JA194T revealed a level of relatedness of only 67 %. The DNA base composition of strain JA194T was 66.67 mol% G+C (by HPLC). Based on 16S rRNA gene sequence analysis, morphological, physiological, Fourier transform infrared fingerprinting and DNA-DNA hybridization studies, strain JA194T (=KCTC 5602T =JCM 14598T) is sufficiently different from other Rhodobacter species to merit its description as the type strain of a novel species, for which the name Rhodobacter megalophilus sp. nov. is proposed.

  1. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.


    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic bact

  2. The bioenergetics of anaerobic bacteria: Evolutionary concepts (United States)

    Dose, K.

    It is widely assumed that the first organisms were fermenting cells growing on prebiotic compounds and that the mode of energy conservation was substrate-level phosphorylation. But the primitive environment was probably relatively short in supply of fermentable substrates. Therefore, new strategies of energy conservation had to be developed relatively early. These include the evolution of membrane-bound phosphorylation systems that were able to use membrane potentials and/or ion gradients for synthesis of energy-rich compounds such as ATP or perhaps inorganic pyrophosphate. A first stage in this development may have been the coupling of membrane-bound decarboxylation to ATP synthesis. The coupling of simple membrane-bound redox reactions to ATP synthesis as modelled by contemporary fumarate or sulfur respiration may have appeared almost simultaneously. In either case, suitable substrates probably were scarce. Therefore the organisms soon may have been forced to develop strategies that were based on less exhaustible resources. These strategies likely included the coupling of membrane-bound ATP synthesis to electron transfer reactions that involved the use of ubiquitous electron acceptors like Fe3+, sulfate or CO2. But with the evolution of more efficient respiratory systems the abiotically produced organic molecules may have become short in supply, so that the evolution of phosphosynthetic CO2 reduction for the production of new biomass must have followed immediately.

  3. Anaerobic infections in the head and neck region. (United States)

    Tabaqchali, S


    Anaerobic bacteria form the predominant flora of the oral cavity, outnumbering facultative organisms by 10-1,000: 1. The type of anaerobic bacteria and their concentration depend on the anatomical site and the degree of anaerobiosis in the different sites in the mouth. Three groups of anaerobic bacteria inhabit the oral cavity; the strict anaerobes, the moderate anaerobes, and the microaerophilic group of organisms. The majority of anaerobic bacterial infections occurring in the region of the mouth, head and neck are caused by the commensal flora. These infections include dental and periodontal disease where the predominant organisms are Bacteroides species, Veillonella, Bifidobacteria, Peptococcus, Peptostreptococcus and Propionibacterium species. More recently, Bacteroides endontalis has been isolated from a periapical abscess of endodontal origin and B. gingivalis, B. intermedius, Haemophilus actinomycetemcomitans and Wollinella species in chronic periodontal disease. Treponema species and other strict anaerobes are seen in smears of severe periodontal disease and acute necrotising gingivitis, but have not yet been isolated in pure culture. Until such time, their role in disease remains uncertain. Fusobacterium nucleatum is specially associated with severe orofacial infections which may extend into the mediastinum. Other anaerobic infections include chronic otitis media, chronic sinusitis and mastoiditis, and brain abscess. Treatment of these conditions should include the use of beta-lactamase resistant antimicrobials, such as clindamycin or one of the nitroimidazoles with penicillin.

  4. Syntrophic anaerobic photosynthesis via direct interspecies electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Phuc T.; Lindemann, Stephen R.; Shi, Liang; Dohnalkova, Alice C.; Fredrickson, James K.; Madigan, Michael T.; Beyenal, Haluk


    Microbial phototrophs are key primary producers on Earth. Currently known electron donors for microbial photosynthesis include H2O, H2, H2S and other reduced inorganic compounds. We describe a new form of metabolism linking anoxygenic photosynthesis to anaerobic respiration, or “syntrophic anoxygenic photosynthesis.” We show that photoautotrophy in green sulfur bacterium Prosthecochloris aestaurii can be driven not only by electrons from a graphite electrode, but also by acetate oxidation via interspecies electron transfer from heterotrophic partner bacterium Geobacter sulfurreducens. P. aestuarii photosynthetic growth using reductant provided by either an electrode or syntrophy was robust and light-dependent. By contrast, P. aestuarii did not grow in co-culture with a G. sulfurreducens mutant lacking a trans-outer membrane porin-cytochrome protein complex required for direct intercellular electron transfer,. This syntrophic interaction suggests revisitation of global carbon cycling in anoxic environments and lays a foundation for further engineering of phototrophic microbial communities for biotechnological applications, such as waste treatment and bioenergy production.

  5. The molecular biological characterization of a strain of biohydrogen-producing anaerobe in Clostridium Genus

    Institute of Scientific and Technical Information of China (English)

    LI Yong-feng; REN Nan-qi; ZHENG Guo-xiang; LIU Min; HU Li-jie; CHEN Ying; WANG Xiang-jing


    The anaerobic process of biohydrogen production was developed recently. The isolation and identification of biohydrogen producing anaerobic bacteria with high evolution rate and yield is an important foundation of the fermented biohydrogen production process through which anaerobic bacteria digest organic wastewater. By considering physiological and biochemical traits, morphological characteristics and a 16S rDNA sequence, the isolated Rennanqilyf33 is shown to be a new species.

  6. New Understanding on Metabolism of Anaerobic Ammonium Oxidation Bacteria Based on Metagenomics Technology%基于宏基因组技术获得的对厌氧氨氧化菌代谢的新理解

    Institute of Scientific and Technical Information of China (English)

    丁爽; 郑平; 陆慧锋; 唐崇俭


    厌氧氨氧化菌(Anaerobic ammonium oxidation bacteria,AAOB)是化能自养菌,由于其生理代谢的奇异性、细胞结构的特殊性以及对氮素循环的重要性,已成为环境工程、微生物以及海洋生物学等领域的研究热点.然而.AAOB未能实现纯培养的现状已成为AAOB代谢途径研究的巨大障碍近年来兴起的宏基因组技术(Metagenomics)为AAOB代谢途径的研究提供了新手段.采用宏基因组技术,可直接研究微生物群体中某特定微生物基因组的结构与功能,摆脱了传统微生物学研究对纯培养的依赖,使未培养微生物的认识和开发成为可能本文首先简述获取AAOB宏基因组信息的过程,然后通过比较由传统代谢研究方法和宏基因组技术获得的AAOB代谢途径的研究成果,论述基于宏基因组技术获得的对AAOB代谢的新理解,得出以下结果和结论:1)AAOB的碳素固定途径为乙酰辅酶A途径,碳素固定的还原力来自NADH或者QH2;2)AAOB氮素转化的重要中问产物是NO,而非NH2OH,并提出了以NO为核心的AAOB代谢的改进模型;3)AAOB的ATP合成途径为氧化磷酸化,推测的电子传递途径为N2H4-QH2-细胞色素bc1 复合体;细胞色素bc1复合体再将电子用于NO2还原和N2H4合成AAOB的宏基因组技术使AAOB代谢途径的研究更具方向性.随着分子生物学理论和技术的不断发展,宏基因组学的升级技术(如宏转录组学、宏蛋白质组学)将为AAOB代谢途径的研究提供新的方法与平台.%Anaerobic ammonium oxidation bacteria (AAOB) belong to chemolitho-autotrophs. AAOB have become one of the research hotspots in the field of environmental engineering, microbiology and oceanography because of their specificities in metabolism, cell structure and nitrogen cycle. However, AAOB can not been cultivated in pure culture, which has become a great obstacle to study their metabolic pathways in further. Nowadays, fast-developing metagenomics provides

  7. Rapid assessment of different oxygenic phototrophs and single-cell photosynthesis with multicolour variable chlorophyll fluorescence imaging

    DEFF Research Database (Denmark)

    Trampe, Erik Christian Løvbjerg; Kolbowski, J.; Schreiber, U.


    We present a new system for microscopic multicolour variable chlorophyll fluorescence imaging of aquatic phototrophs. The system is compact and portable and enables microscopic imaging of photosynthetic performance of individual cells and chloroplasts using different combinations of blue, green, ...

  8. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.


    with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  9. Growth Characteristics of Tetraselmis sp.-1 in Phototrophic, Mixotrophic and Heterotrophic Conditions

    Institute of Scientific and Technical Information of China (English)

    Shen Jihong(沈继红); Yu Junhong; Lin Xuezheng; Li Guangyou; Liu Fayi


    Tetraselmis sp.-1 is a new microalgae strain constructed by cell fusion technique. In this paper, the growth characteristics of Tetraselmis sp.-1 under different culture conditions are investigated. The growth kinetic models are obtained, the assimilation of C and NH4+ is investigated and the assimilation efficiency of Tetraselmis sp.-1 under different culture conditions is calculated. The results show that different culture conditions do not have obvious influence on carbon absorbance, but have significant influence on nitrogen absorbance, C∶N is maximum under heterotrophic condition, while minimum under phototrophic condition. The assimilation efficiency (η) of Tetraselmis sp.-1 has the highest value in heterotrophic condition and largely higher than those in phototrophic and mixotrophic conditions.


    Directory of Open Access Journals (Sweden)

    Oana-Adriana CUZMAN


    Full Text Available Five natural antibiofoulants with terrestrial (capsaicine - CS, cinnamaldehyde - CI and marine origin (zosteric acid - ZA, poly-alkylpyridinium salts - pAPS and Ceramium botryocarpum extract - CBE have been selected and tested against phototrophic biofilm formation on the stone surfaces for their inhibitory properties. The antibiofouling agents (ABAs were incorporated into two commercial silicone based coatings (Silres BS OH 100 - S and Silres BS 290 - W. In this work, phototrophic growth was evaluated by epifluorescence microscopy and semi-quantitative image analysis. The results showed an inhibitory efficiency for almost all tested ABAs. However, this efficiency has been found for short time or when the incorporating agent were incompletely cured. Among the ABAs tested, the poly-alkylpyridinium salts and cinnamaldehyde incorporated into Silres BS 290 showed the best inhibitory efficiency.

  11. How to make a living from anaerobic ammonium oxidation

    NARCIS (Netherlands)

    Kartal, B.; De Almeida, N.M.; Maalcke, W.J.; Op den Camp, H.J.M.; Jetten, M.S.M.; Keltjens, J.T.


    Anaerobic ammonium-oxidizing (anammox) bacteria primarily grow by the oxidation of ammonium coupled to nitrite reduction, using CO2 as the sole carbon source. Although they were neglected for a long time, anammox bacteria are encountered in an enormous species (micro)diversity in virtually any anoxi

  12. The evolution of glutathione metabolism in phototrophic microorganisms (United States)

    Fahey, Robert C.; Buschbacher, Ralph M.; Newton, Gerald L.


    The low molecular weight thiol composition of a variety of phototropic microorganisms is examined in order to ascertain how evolution of glutathione (GSH) production is related to the evolution of oxygenic photosynthesis. Cells were extracted in the presence of monobromobimane (mBBr) to convert thiols (RSH) to fluorescent derivatives (RSmB) which were analyzed by high performance liquid chromatography (HPLC). Significant levels of GSH were not found in green sulfur bacteria. Substantial levels were present in purple bacteria, cyanobacteria, and eukaryotic algae. Other thiols measured included cysteine, gamma-glutamylcysteine, thiosulfate, coenzyme A, and sulfide. Many of the organisms also exhibited a marked ability to reduce mBBr to syn-(methyl,methyl)bimane, an ability which was quenched by treatment with 2-pyridyl disulfide or 5,5 prime-bisdithio - (2-nitrobenzoic acid) prior to reaction with mBBr. These observations indicate the presence of a reducing system capable of electron transfer to mBBr and reduction of reactive disulfides. The distribution of GSH in phototropic eubacteria indicates that GSH synthesis evolved at or around the time that oxygenic photosynthesis evolved.

  13. Enhanced algae growth in both phototrophic and mixotrophic culture under blue light. (United States)

    Das, Probir; Lei, Wang; Aziz, Siti Sarah; Obbard, Jeffrey Philip


    Biomass productivity and fatty acid methyl esters (FAME) derived from intracellular lipid of a Nannochloropsis sp. isolated from Singapore's coastal waters were studied under different light wavelengths and intensities. Nannochloropsis sp., was grown in both phototrophic and mixotrophic (glycerol as the carbon source) culture conditions in three primary monochromatic light wavelengths, i.e., red, green and blue LEDs, and also in white LED. The maximum specific growth rate (μ) for LEDs was blue>white>green>red. Nannochloropsis sp. achieved a μ of 0.64 and 0.66 d(-1) in phototrophic and mixotrophic cultures under blue lighting, respectively. The intracellular fatty acid composition of Nannochloropsis sp. varied between cultures exposed to different wavelengths, although the absolute fatty acid content did differ significantly. Maximum FAME yield from Nannochloropsis sp. was 20.45% and 15.11% of dry biomass weight equivalent under photo- and mixotrophic culture conditions respectively for cultures exposed to green LED (550 nm). However, maximum volumetric FAME yield was achieved for phototrophic and mixotrophic cultures (i.e., 55.13 and 111.96 mg/l, respectively) upon cell exposure to blue LED (470 nm) due to highest biomass productivity. It was calculated that incremental exposure of light intensity over the cell growth cycle saves almost 20% of the energy input relative to continuous illumination for a given light intensity.

  14. Light structures phototroph, bacterial and fungal communities at the soil surface.

    Directory of Open Access Journals (Sweden)

    Lawrence O Davies

    Full Text Available The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0-3 mm and bulk soil (3-12 mm using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere.

  15. Characteristics of extracellular polymeric substances of phototrophic biofilms at different aquatic habitats. (United States)

    Fang, Fang; Lu, Wen-Tao; Shan, Qi; Cao, Jia-Shun


    Three different phototrophic biofilms obtained from a natural lake (Sample 1), drinking water plant (Sample 2) and wastewater treatment plant (Sample 3) were investigated. Diatoms and green algae were the dominant algae of three biofilms, and the biomass was highest in biofilm of Sample 2. The three phototrophic biofilms also had variable extracellular polymeric substances (EPS) concentrations and compositions. Total EPS concentration of 14.80 mg/g DW was highest in biofilm of Sample 2, followed by biofilms of Samples 3 and 1 (13.11 and 12.29 mg/g DW). Tightly bound EPS (TB-EPS) were the main fraction, and polysaccharides and protein were the main components of total EPS in all three biofilms. However, the compositions of loosely bound EPS (LB-EPS) and TB-EPS were different in three biofilms. Fourier-transform infrared and fluorescence spectra indicated different structure and compositions of LB-EPS and TB-EPS. These results demonstrated the characteristics of EPS produced by phototrophic biofilms varied and had compact relation to their growth environmental conditions.

  16. Gain and loss of phototrophic genes revealed by comparison of two Citromicrobium bacterial genomes.

    Directory of Open Access Journals (Sweden)

    Qiang Zheng

    Full Text Available Proteobacteria are thought to have diverged from a phototrophic ancestor, according to the scattered distribution of phototrophy throughout the proteobacterial clade, and so the occurrence of numerous closely related phototrophic and chemotrophic microorganisms may be the result of the loss of genes for phototrophy. A widespread form of bacterial phototrophy is based on the photochemical reaction center, encoded by puf and puh operons that typically are in a 'photosynthesis gene cluster' (abbreviated as the PGC with pigment biosynthesis genes. Comparison of two closely related Citromicrobial genomes (98.1% sequence identity of complete 16S rRNA genes, Citromicrobium sp. JL354, which contains two copies of reaction center genes, and Citromicrobium strain JLT1363, which is chemotrophic, revealed evidence for the loss of phototrophic genes. However, evidence of horizontal gene transfer was found in these two bacterial genomes. An incomplete PGC (pufLMC-puhCBA in strain JL354 was located within an integrating conjugative element, which indicates a potential mechanism for the horizontal transfer of genes for phototrophy.

  17. Molecular analysis of the distribution and phylogeny of the soxB gene among sulfur-oxidizing bacteria - evolution of the Sox sulfur oxidation enzyme system. (United States)

    Meyer, Birte; Imhoff, Johannes F; Kuever, Jan


    The soxB gene encodes the SoxB component of the periplasmic thiosulfate-oxidizing Sox enzyme complex, which has been proposed to be widespread among the various phylogenetic groups of sulfur-oxidizing bacteria (SOB) that convert thiosulfate to sulfate with and without the formation of sulfur globules as intermediate. Indeed, the comprehensive genetic and genomic analyses presented in the present study identified the soxB gene in 121 phylogenetically and physiologically divergent SOB, including several species for which thiosulfate utilization has not been reported yet. In first support of the previously postulated general involvement of components of the Sox enzyme complex in the thiosulfate oxidation process of sulfur-storing SOB, the soxB gene was detected in all investigated photo- and chemotrophic species that form sulfur globules during thiosulfate oxidation (Chromatiaceae, Chlorobiaceae, Ectothiorhodospiraceae, Thiothrix, Beggiatoa, Thiobacillus, invertebrate symbionts and free-living relatives). The SoxB phylogeny reflected the major 16S rRNA gene-based phylogenetic lineages of the investigated SOB, although topological discrepancies indicated several events of lateral soxB gene transfer among the SOB, e.g. its independent acquisition by the anaerobic anoxygenic phototrophic lineages from different chemotrophic donor lineages. A putative scenario for the proteobacterial origin and evolution of the Sox enzyme system in SOB is presented considering the phylogenetic, genomic (sox gene cluster composition) and geochemical data.

  18. Molecular evolution of the nif gene cluster carrying nifI1 and nifI2 genes in the Gram-positive phototrophic bacterium Heliobacterium chlorum. (United States)

    Enkh-Amgalan, Jigjiddorj; Kawasaki, Hiroko; Seki, Tatsuji


    A major nif cluster was detected in the strictly anaerobic, Gram-positive phototrophic bacterium Heliobacterium chlorum. The cluster consisted of 11 genes arranged within a 10 kb region in the order nifI1, nifI2, nifH, nifD, nifK, nifE, nifN, nifX, fdx, nifB and nifV. The phylogenetic position of Hbt. chlorum was the same in the NifH, NifD, NifK, NifE and NifN trees; Hbt. chlorum formed a cluster with Desulfitobacterium hafniense, the closest neighbour of heliobacteria based on the 16S rRNA phylogeny, and two species of the genus Geobacter belonging to the Deltaproteobacteria. Two nifI genes, known to occur in the nif clusters of methanogenic archaea between nifH and nifD, were found upstream of the nifH gene of Hbt. chlorum. The organization of the nif operon and the phylogeny of individual and concatenated gene products showed that the Hbt. chlorum nif operon carrying nifI genes upstream of the nifH gene was an intermediate between the nif operon with nifI downstream of nifH (group II and III of the nitrogenase classification) and the nif operon lacking nifI (group I). Thus, the phylogenetic position of Hbt. chlorum nitrogenase may reflect an evolutionary stage of a divergence of the two nitrogenase groups, with group I consisting of the aerobic diazotrophs and group II consisting of strictly anaerobic prokaryotes.



    Harerimana, Casimir; Vasel, Jean-Luc; Jupsin, Hugues; Ouali, Amira


    The aim of the study was first to develop a simple and practical model of anaerobic digestion including sulphate-reduction in anaerobic ponds. The basic microbiology of our model consists of three steps, namely, acidogenesis, methanogenesis, and sulphate reduction. This model includes multiple reaction stoichiometry and substrate utilization kinetics. The second aim was to determine some kinetic parameters associated with this model. The values of these parameters for sulfidogenic bacteria ar...

  20. Competition for inorganic carbon between oxygenic and anoxygenic phototrophs in a hypersaline microbial mat, Guerrero Negro, Mexico. (United States)

    Finke, Niko; Hoehler, Tori M; Polerecky, Lubos; Buehring, Benjamin; Thamdrup, Bo


    While most oxygenic phototrophs harvest light only in the visible range (400-700 nm, VIS), anoxygenic phototrophs can harvest near infrared light (> 700 nm, NIR). To study interactions between the photosynthetic guilds we used microsensors to measure oxygen and gross oxygenic photosynthesis (gOP) in a hypersaline microbial mat under full (VIS + NIR) and VIS illumination. Under normal dissolved inorganic carbon (DIC) concentrations (2 mM), volumetric rates of gOP were reduced up to 65% and areal rates by 16-31% at full compared with VIS illumination. This effect was enhanced (reduction up to 100% in volumetric, 50% in areal rates of gOP) when DIC was lowered to 1 mM, but diminished at 10 mM DIC or lowered pH. In conclusion, under full-light illumination anoxygenic phototrophs are able to reduce the activity of oxygenic phototrophs by efficiently competing for inorganic carbon within the highly oxygenated layer. Anoxygenic photosynthesis, calculated from the difference in gOP under full and VIS illumination, represented between 10% and 40% of the C-fixation. The DIC depletion in the euphotic zone as well as the significant C-fixation by anoxygenic phototrophs in the oxic layer influences the carbon isotopic composition of the mat, which needs to be taken into account when interpreting isotopic biosignals in geological records.

  1. Enzymes involved in the anaerobic oxidation of n-alkanes: from methane to long-chain paraffins


    Callaghan, Amy V.


    Anaerobic microorganisms play key roles in the biogeochemical cycling of methane and non-methane alkanes. To date, there appear to be at least three proposed mechanisms of anaerobic methane oxidation (AOM). The first pathway is mediated by consortia of archaeal anaerobic methane oxidizers and sulfate-reducing bacteria via ‘reverse methanogenesis’ and is catalyzed by a homologue of methyl-coenzyme M reductase. The second pathway is also mediated by anaerobic methane oxidizers and sulfate-red...

  2. Research in anti- anaerobe mechanism of nanometer materials%纳米材料抗厌氧菌机制研究

    Institute of Scientific and Technical Information of China (English)

    熊德鑫; 梁明


    AIM:To investigate the antimicrobial spectrum of nanometer materials to 33 strains of ordinary anaerobic pathogenic bacteria isolated from 11 genera. METHODS:The anti anaerobic effects of nanometer materials were examined and measured by test tube dilution method.RESULTS:In most tubes, there were no bacteria growth in nanometer suspension.CONCLUSION: there is a wide antimicrobial spectrum of nanometer materials and it can effectively inhibit the growth of the anaerobic bacteria.

  3. Environmental drivers of phototrophic biofilms in an Alpine show cave (SW-Italian Alps)

    Energy Technology Data Exchange (ETDEWEB)

    Piano, E., E-mail: [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy); Bona, F.; Falasco, E. [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy); La Morgia, V. [ISPRA, via Ca' Fornacetta, 9, 40064 Ozzano dell' Emilia (Italy); Badino, G. [Department of Physics, University of Turin, Via P. Giuria 1, 10125 Turin (Italy); Isaia, M. [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy)


    The proliferation of lampenflora is a major threat for the conservation of show caves, since phototrophic organisms cause physical, chemical and aesthetic damage to speleothems. In this paper we examine the environmental factors influencing the presence and the growth of the three main photosynthetic groups composing phototrophic biofilms in the Bossea show cave (SW-Italian Alps). The presence and the primary production of cyanobacteria, diatoms and green algae were detected with BenthoTorch®, an instrument for in situ measurement of chlorophyll a concentration that has never been used before in caves. By means of different techniques of regression analysis, we highlighted the response of the three photosynthetic groups to different environmental factors. Illuminance proved to be the main factor influencing positively both the probability of the presence and the productivity of the three groups. The presence of seeping water on the substrate and the distance from the cave entrance proved to play an important role in determining patterns of colonization. By means of GIS techniques, we provide thematic maps of the cave, providing a representation of pattern of the density of the three examined photosynthetic groups within different areas of the cave. The same approach may apply to other show caves, aiming at providing suggestions for the cave management (i.e. cleaning of the cave walls and positioning of artificial lights) and reduce impact caused by tourism. - Highlights: • We used a PAM fluorimeter on autotrophic biofilms in a show cave for the first time. • We modelled the environmental factors influencing phototrophic biofilms. • Illuminance, moisture and distance from the entrance proved to be significant. • We produced thematic maps illustrating our results. • We provide suggestions for cave management.

  4. Modeling the Habitat Range of Phototrophic Microorganisms in Yellowstone National Park: Toward the Development of a Comprehensive Fitness Landscape

    Directory of Open Access Journals (Sweden)

    Eric eBoyd


    Full Text Available The extent to which geochemical variation constrains the distribution of phototrophic metabolisms was modeled based on 439 observations in geothermal springs in Yellowstone National Park (YNP, Wyoming. Generalized additive models (GAMs were developed to predict the distribution of photosynthesis as a function of spring temperature, pH, and total sulfide. GAMs comprised of temperature explained 42.7% of the variation in the distribution of phototrophic metabolisms whereas GAMs comprised of sulfide and pH explained 20.7% and 11.7% of the variation, respectively. These results suggest that of the measured variables, temperature is the primary constraint on the distribution of phototrophic metabolism in YNP. GAMs comprised of multiple variables explained a larger percentage of the variation in the distribution of phototrophic metabolism, indicating additive interactions among variables. A GAM that combined temperature and sulfide explained the greatest variation in the dataset (54.8% while minimizing the introduction of degrees of freedom. In an effort to verify the extent to which phototroph distribution reflects constraints on activity, we examined the influence of sulfide and temperature on dissolved inorganic carbon (DIC uptake rates under both light and dark conditions. Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, bacterial-dominated systems. In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature. Collectively, these results suggest that the habitat range of phototrophs in YNP springs, specifically that of cyanobacteria and algae, largely results from constraints imposed by temperature and sulfide on the activity and fitness of these populations, a finding that is consistent with the predictions from GAMs.

  5. Anaerobic catabolism of aromatic compounds: a genetic and genomic view. (United States)

    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


    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.

  6. Subculturing of a polychlorinated biphenyl-dechlorinating anaerobic enrichment on solid media

    Energy Technology Data Exchange (ETDEWEB)

    May, H.D.; Boyle, A.W.; Price, W.A. II.; Blake, C.K. (Celgene Corp., Warren, NJ (United States))


    An anaerobic culture capable of dechlorinating polychlorinated biphenyls was subcultured under strict anaerobic conditions on solid media containing sterilized river sediment. The dechlorination activity was transferred as a bacterial colony on a solid medium three times. After two transfers on solid medium, the culture was no longer methanogenic but still dechlorinated a mixture of tri- and tetrachlorobiphenyls. This demonstrates that anaerobic bacteria are responsible for the polychlorinated biphenyl dechlorination and can be grown without polychlorinated biphenyl on solid media.

  7. Molecular characterization and fermentative hydrogen production of a wild anaerobe in clostridium genus

    Institute of Scientific and Technical Information of China (English)

    LI Yongfeng; REN Nanqi; YANG Chuanping; LI Jianzheng; LI Peng


    Anaerobic process of biohydrogen production is developed in this paper.The isolation and identification of high efficient biohydrogen production anaerobic bacteria are the important foundations for the fermented biohydrogen production process by anaerobic digesting organic wastewater.Taking the physiological and biochemical traits,the morphological characteristics and 16S rDNA sequence into consideration,the isolate Rennanqilyf33 is a new species.

  8. A review on regulation methods of nitrite oxidizing bacteria in one-stage anaerobic ammonia oxidation process%一段式厌氧氨氧化工艺亚硝酸盐氧化菌抑制方法研究进展

    Institute of Scientific and Technical Information of China (English)

    谢丽; 殷紫; 尹志轩; 王悦超; 周琪


    近年来,厌氧氨氧化工艺(anaerobic ammonium oxidation, Anammox)作为一种新型的脱氮技术,由于其耗能少、效率高而被应用于高氨氮废水的处理中。然而,实际运行的厌氧氨氧化工程中有时会出现亚硝酸盐氧化菌(nitrite oxidizing bacteria, NOB)大量繁殖的情况,导致硝酸盐积累,脱氮效率下降。在一段式 Anammox 反应器中,通过控制某些影响因素,如调节体系中的溶解氧,控制游离氨和游离亚硝酸的浓度,调控碳源浓度以及外加中间产物(N2H4、NO 和 NH2OH)等方式,能够在维持 Anammox 工艺脱氮效率的同时有效抑制 NOB。除了系统地综述一段式 Anammox 工艺中 NOB 抑制手段以外,将进一步讨论实际 Anammox 工程应用中抑制 NOB 大量繁殖行之有效的手段。%In recent years,anaerobic ammonium oxidation (Anammox), a new technology for nitrogen removal, has been used in the treatment of high-strength ammonia wastewater due to its low energy consumption and high treatment efficiency. Whereas, the accumulation of nitrite oxidizing bacteria (NOB) often occurs in full-scale Anammox process, leading to the accumulation of nitrate and deterioration of nitrogen removal effectiveness. In two-stage Anammox processes, NOB accumulation often occurs in partial nitritation stage, the inhibition of which has been discussed in details. While in one-stage Anammox process, NOB accumulation is more common and fatal due to the complexity brought by the coexistence of functional bacteria like ammonium oxidizing bacteria (AOB), NOB, anaerobic ammonia oxidizing bacteria (AnAOB) and denitrifiers. It has been reported that NOB could be effectively suppressed in the one-stage Anammox process by some methods, e.g. regulating dissolved oxygen, altering the free ammonia and free nitrous acid concentration, adjusting carbon source and adding externally intermediate products (N2H4, NO, NH2OH), etc. The regulation methods


    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher


    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

  10. Complex community of nitrite-dependent anaerobic methane oxidation bacteria in coastal sediments of the Mai Po wetland by PCR amplification of both 16S rRNA and pmoA genes. (United States)

    Chen, Jing; Zhou, Zhichao; Gu, Ji-Dong


    In the present work, both 16S rRNA and pmoA gene-based PCR primers were employed successfully to study the diversity and distribution of n-damo bacteria in the surface and lower layer sediments at the coastal Mai Po wetland. The occurrence of n-damo bacteria in both the surface and subsurface sediments with high diversity was confirmed in this study. Unlike the two other known n-damo communities from coastal areas, the pmoA gene-amplified sequences in the present work clustered not only with some freshwater subclusters but also within three newly erected marine subclusters mostly, indicating the unique niche specificity of n-damo bacteria in this wetland. Results suggested vegetation affected the distribution and community structures of n-damo bacteria in the sediments and n-damo could coexist with sulfate-reducing methanotrophs in the coastal ecosystem. Community structures of the Mai Po n-damo bacteria based on 16S rRNA gene were different from those of either the freshwater or the marine. In contrast, structures of the Mai Po n-damo communities based on pmoA gene grouped with the marine ones and were clearly distinguished from the freshwater ones. The abundance of n-damo bacteria at this wetland was quantified using 16S rRNA gene PCR primers to be 2.65-6.71 × 10(5) copies/g dry sediment. Ammonium and nitrite strongly affected the community structures and distribution of n-damo bacteria in the coastal Mai Po wetland sediments.

  11. Genus specific unusual carotenoids in purple bacteria, Phaeospirillum and Roseospira: structures and biosyntheses. (United States)

    Takaichi, Shinichi; Maoka, Takashi; Sasikala, Ch; Ramana, Ch V; Shimada, Keizo


    Phototrophic bacteria necessarily contain carotenoids for photosynthesis, and a few phototrophic purple bacteria accumulate unusual carotenoids. The carotenoids in the genera Phaeospirillum and Roseospira were identified using spectroscopic methods. All species of the genus Phaeospirillum contained characteristic polar carotenoids in addition to lycopene and hydroxylycopene (rhodopin); hydroxylycopene glucoside, dihydroxylycopene, and its mono- and/or diglucosides. From the structures of these carotenoids, their accumulation was suggested to be due to absence of CrtD (acyclic carotenoid C-3,4 desaturase) and to possession of glucosyltransferase. Species of the genus Roseospira have been reported to have unusual absorption spectra in acetone extract, and they were found to accumulate 3,4-didehydrorhodopin as a major carotenoid. This may be due to low activity of CrtF (acyclic 1-hydroxycarotenoid methyltransferase). The study concludes in identifying genus specific unusual carotenoids, which is probably due to characteristic nature of some carotenogenesis enzymes.

  12. Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor. (United States)

    Wang, Jin; Mahmood, Qaisar; Qiu, Jiang-Ping; Li, Yin-Sheng; Chang, Yoon-Seong; Li, Xu-Dong


    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 m(3) of biogas per m(3) of POME which was utilized for electricity generation.

  13. Eukaryotic microbial diversity of phototrophic microbial mats in two Icelandic geothermalhot springs. (United States)

    Aguilera, Angeles; Souza-Egipsy, Virginia; González-Toril, Elena; Rendueles, Olaya; Amils, Ricardo


    The composition of the eukaryotic community and the three-dimensional structure of diverse phototrophic microbial mats from two hot springs in Iceland (Seltun and Hveradalir geothermal areas) were explored by comparing eukaryotic assemblages from microbial mats. Samples were collected in July 2007 from 15 sampling stations along thermal and pH gradients following both hot springs. Physicochemical data revealed high variability in terms of pH (ranging from 2.8 to 7), with high concentrations of heavy metals, including up to 20 g Fe/l, 80 mg Zn/l, 117 mg Cu/l, and 39 mg Ni/l at the most acidic sampling points. Phylogenetic analysis of 18S rDNA genes revealed a diversity of sequences related to several taxa, including members of the Bacillariophyta, Chlorophyta, Rhodophyta, and Euglenophyta phyla as well as ciliates, amoebae, and stramenopiles. The closest relatives to some of the sequences detected came from acidophilic organisms, even when the samples were collected at circumneutral water locations. Electron microscopy showed that most of the microecosystems analyzed were organized as phototrophic microbial mats in which filamentous cyanobacteria usually appeared as a major component. Deposits of amorphous minerals rich in silica, iron, and aluminium around the filaments were frequently detected.

  14. Phototrophic phylotypes dominate mesothermal microbial mats associated with hot springs in Yellowstone National Park. (United States)

    Ross, Kimberly A; Feazel, Leah M; Robertson, Charles E; Fathepure, Babu Z; Wright, Katherine E; Turk-Macleod, Rebecca M; Chan, Mallory M; Held, Nicole L; Spear, John R; Pace, Norman R


    The mesothermal outflow zones (50-65°C) of geothermal springs often support an extensive zone of green and orange laminated microbial mats. In order to identify and compare the microbial inhabitants of morphologically similar green-orange mats from chemically and geographically distinct springs, we generated and analyzed small-subunit ribosomal RNA (rRNA) gene amplicons from six mesothermal mats (four previously unexamined) in Yellowstone National Park. Between three and six bacterial phyla dominated each mat. While many sequences bear the highest identity to previously isolated phototrophic genera belonging to the Cyanobacteria, Chloroflexi, and Chlorobi phyla, there is also frequent representation of uncultured, unclassified members of these groups. Some genus-level representatives of these dominant phyla were found in all mats, while others were unique to a single mat. Other groups detected at high frequencies include candidate divisions (such as the OP candidate clades) with no cultured representatives or complete genomes available. In addition, rRNA genes related to the recently isolated and characterized photosynthetic acidobacterium "Candidatus Chloracidobacterium thermophilum" were detected in most mats. In contrast to microbial mats from well-studied hypersaline environments, the mesothermal mats in this study accrue less biomass and are substantially less diverse, but have a higher proportion of known phototrophic organisms. This study provides sequences appropriate for accurate phylogenetic classification and expands the molecular phylogenetic survey of Yellowstone microbial mats.

  15. Exploring the secrets of the three-dimensional architecture of phototrophic biofilms in caves

    Directory of Open Access Journals (Sweden)

    Roldàn Monica


    Full Text Available Caves with dim natural light, and lighted hypogean environments, have been found to host phototrophic microorganisms from varioustaxonomic groups. These microorganisms group themselves into assemblies known as communities or biofilms, which are associated withrock surfaces. In this work, the phototrophic biofilms that colonise speleothems, walls and floors in three tourist caves (Spain were studied.Confocal laser scanning microscopy (CLSM and scanning electron microscopy (SEM were used to study these organisms and acquirethree-dimensional data on their biofilm structure. CLSM was used in a multi-channel mode whereby the different channels map individualbiofilm components. Cyanobacteria, green microalgae, diatoms, mosses and lichens were found to be grouped as biofilms that differedaccording to the sampling sites. The biofilms were classified into six types regarding their environmental conditions. These types weredefined by their constituent organisms, the thickness of their photosynthetic layers and their structure. Light-related stress is associated with lower biofilm thickness and species diversity, as is low humidity, and, in the case of artificially illuminated areas, the duration of lightexposure.

  16. Different carbon isotope fractionation patterns during the development of phototrophic freshwater and marine biofilms

    Directory of Open Access Journals (Sweden)

    M. Staal


    Full Text Available Natural phototrophic biofilms are influenced by a broad array of abiotic and biotic factors and vary over temporal and spatial scales. Different developmental stages can be distinguished and growth rates will vary due to the thickening of the biofilm, which is expected to lead to a limitation of light or mass transport. This study shows that variation in CO2(aq availability leads to a fractionation shift and thereby affects δ13C signatures during biofilm development. For phototrophic freshwater biofilms it was found that the δ13C value became less negative with the thickening of the biofilm, while the opposite trend was found in marine biofilms. Modeling and pH profiling indicated that the trend in the freshwater system was caused by an increase in CO2(aq limitation resulting in an increase of HCO3 as C-source. The opposite trend in the marine system could be explained by a higher heterotrophic biomass and activity causing a higher carbon recycling and thereby lower δ13C values. We conclude that δ13C was more related to the net areal photosynthesis rate and carbon recycling, rather than to the growth rate of the biofilms.

  17. Isolation and Identification of Phototrophic Microorganisms from Rudkhan Castle as a Biodeteriorating Agent

    Directory of Open Access Journals (Sweden)

    Parisa Mohammadi


    Full Text Available Introduction: Phototrophic microorganisms are the first residents of different surfaces of ancient buildings’ walls. These organisms can expand to provide the colonization of other microorganisms and to form microbial biofilms. During biofilm growth, acids and metabolites production bore the substratum and cause surfaces damages. Rudkan Castle, the historic monument located in Gilan province, an area with a humid climate has an appropriate surfaces to grow these microorganisms. Materials and methods: In this study, morphological identification of algae and cyanobacteria which was isolated from different areas of the brick walls of Castle has been investigated. Samples were taken from 24 different areas of Castle walls and were aseptically cultured into Blue Green Medium (BGM and Bolds Basal Medium (BBM, and colonies were observed using light microscopy. Results: The dominant organisms which were isolated and identified, were Cladophora, Trentepohlia, Klebsormidium, Trebouxia, Pleurastrum, Chlorococcum as chlorophyta order and Scytonema, Tolypothrix, Leptolyngbya, Plectolyngbya, Phormidium, Gloeocapsa, Microcoleus, Nostoc as a cyanobacteria order. Discussion and conclusion: As expected, diversity of a large number of cyanobacteria and algae phototrophs was isolated. Diversity of organisms on the surface of monuments depends on many factors, including the weather condition such as moisture, the amount of radiation absorbed by the surface, temperature of area, the materials used in the monuments, the biological acceptance of surface and presence of variety of organisms in the soil surface and the air on. Study of destructive factors is the first step toward the protection and restoration of ancient monuments.

  18. Anaerobic Digestion and its Applications (United States)

    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...

  19. Overview of the anaerobic toxicity caused by organic forest industry wastewater pollutants.

    NARCIS (Netherlands)

    Sierra-Alvarez, R.; Field, J.A.; Kortekaas, S.; Lettinga, G.


    Numerous types of organic environmental pollutants are encountered in forest industry effluents which potentially could inhibit consortia of anaerobic bacteria. The purpose of this study was to collect anaerobic bioassay data from the literature to better estimate the impact of these pollutants on a

  20. High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Mikkelsen, Marie Just; Ahring, Birgitte Kiær


    The low ethanol tolerance of thermophilic anaerobic bacteria, generally less than 2% (v/v) ethanol, is one of the main limiting factors for their potential use for second generation fuel ethanol production. In this work, the tolerance of thermophilic anaerobic bacterium Thermoanaerobacter BG 1L1 ...

  1. 柑橘黄龙病兼性厌氧型伴生细菌的分离及优势菌群分析%Isolation of facultative anaerobic and entophytic bacteria companioned Huanglongbing pathogen-infected citrus tissues and determination of dominant bacterial populations

    Institute of Scientific and Technical Information of China (English)

    李颜方; 殷幼平; 王玉玺; 李佳; 陈世伟; 王中康


    柑橘黄龙病是世界柑橘生产上最具毁灭性的病害,主要由难人工培养的韧皮杆菌所引起(Candidatus Liberibacter asiaticus)[1].近年的研究结果表明黄龙病发病组织内除了韧皮杆菌外,还可能有促进或抑制黄龙病菌生长的伴生性细菌[2,3].国内外已有不少关于植物内生细菌的研究报道[4],但关于柑橘内生细菌的报道较少.本研究旨在以多年生发病与健康柑橘植株的内生细菌为研究对象,采用定向分离方法培养兼性厌氧型内生细菌,利用基于16S rRNA的PCR-DGGE宏基因组学方法分析比较柑橘健株与病株内生菌群的差异,旨在发现与黄龙病伴生的功能性内生细菌.%To analyze the diversity of entophytic bacteria and find the companion microbe in Huanglongbing pathogen-infected and healthy citrus plant tissues, various parts of citrus tissues were collected from different locations of citrus planting areas. The facultative anaerobic and entophytic bacteria were isolated and identified based on bacterial morphology, physiology, biochemistry characteristics and PCR-DGGE analysis (denaturing gradient gel electrophoresis, analysis of the sequence of 16S rRNA V6-V8 fragment). By the directional isolation of the facultative anaerobic and entophytic bacteria and 16S rDNA amplification methods, total 12 genera of bacteria were identified from 19 cultivable bacterial populations. The dominant bacterial population were Bacillus sp. (IF: 21.03% ), Planococcus sp. (IF:20.69% ) and Pseudomonas sp. (IF: 17.44% ) in healthy citrus tissues, while Curtobacterium sp. (IF: 29.07% ), Bacillus sp. (IF: 23.12% ) , Microbacterium sp. (IF; 21.09% )in infected citrus plants. Based on the results of DGGE, 9 genera of cultured bacteria were identified. The dominant bacteria population was Serratia sp. (IF: 28% ), and Pantoea sp. (IF: 14% ) was second only to it. ' Candidatus Liberibacter asiaticus' was found only in tangerine pith of deformed orange fruit

  2. Diversity of anaerobic microbes in spacecraft assembly clean rooms. (United States)

    Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L; Venkateswaran, Kasthuri


    Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities.

  3. 两种漱口液对口腔挥发性硫化物及舌背细菌的影响%The effect of two kinds of mouthwash on the volatile sulfur compounds and the anaerobic bacteria of tongue dorsum

    Institute of Scientific and Technical Information of China (English)

    王金华; 蒋琳; 胡赟


    目的 评价常见的两种市售漱口液对口腔挥发性硫化物水平及舌背菌群的影响.方法 采用为期1月的单中心、随机、对照、双盲的临床研究方法.研究对象共60人.分为李斯德林漱口液组(A组),高露洁贝齿漱口液组(B组),阴性对照组(C组).分别在基线、半个月、1个月时检测各组研究对象的口腔挥发性硫化物水平及舌背厌氧菌的数量变化,并进行统计学分析处理.结果 对于口腔挥发性硫化物水平,在半个月及1个月时,A组、B组均有明显的下降,均优于C组,差异具有统计学意义(P0.05).结论 李斯德林漱口液及高露洁贝齿漱口液均能有效降低口腔挥发性硫化物水平及舌背厌氧菌的数量,且李斯德林漱口液降低硫化物的效果更优.%Objective To evaluate the effect of two kinds of mouthwash on the levels of the volatile sulfur compounds and the anaerobic bacteria of tongue dorsum. Method The trial adopted a dual-center, randomized, double-blind,controlled clinical methods, which lasted for one month. A total of 60 subjects were selected and randomly allocated in three groups, Listerine group, Colgate group and placebo group. Recordings were assessed statistically at the baseline, half a month and one month, which included the level of the volatile sulfur compounds and quantitity changes of bacteria of the tongue dorsum. Result At half a month and one month, the Listerine group and Colgate group had a significant reduction in the VSCs scores, which got a better effect in comparison to the placebo group with a significant statistically difference (P < 0.05), and there was a significant statistically difference between Listerine group and Colgate group. At the same time, the Listerine group and Colgate group resulted in a significant reduction in the total anaerobic bacteria of tongue dorsum,which got a better effect in comparison to the placebo group with a significant statistically difference (P < 0

  4. Phylogenetic and metabolic diversity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming bacteria in strictly anaerobic mixed cultures enriched on RDX as nitrogen source. (United States)

    Zhao, Jian-Shen; Spain, Jim; Hawari, Jalal


    Five obligate anaerobes that were most closely related to Clostridium bifermentans, Clostridium celerecrescens, Clostridium saccharolyticum, Clostridium butyricum and Desulfovibrio desulfuricans by their 16S rRNA genes sequences were isolated from enrichment cultures using hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as a nitrogen source. The above isolates transformed RDX at rates of 24.0, 5.4, 6.2, 2.5, 5.5 mumol h(-1) g (dry weight) of cells(-1), respectively, to nitrite, formaldehyde, methanol, and nitrous oxide. The present results indicate that clostridia are major strains responsible for RDX removal, and all isolates seemed to mainly transform RDX via its initial reduction to MNX and subsequent denitration. Since clostridia are commonly present in soil, we suggest that they may contribute to the removal of RDX in the subsurface (anoxic) soil.

  5. Nutrient Removal and Biomass Production in an Outdoor Pilot-Scale Phototrophic Biofilm Reactor for Effluent Polishing

    NARCIS (Netherlands)

    Boelee, N.C.; Janssen, M.; Temmink, H.; Shrestha, R.; Buisman, C.J.N.; Wijffels, R.H.


    An innovative pilot-scale phototrophic biofilm reactor was evaluated over a 5-month period to determine its capacity to remove nitrogen and phosphorus from Dutch municipal wastewater effluents. The areal biomass production rate ranged between 2.7 and 4.5 g dry weight/m2/day. The areal nitrogen and p

  6. Soil surface colonization by phototrophic indigenous organisms, in two contrasted soils treated by formulated maize herbicide mixtures. (United States)

    Joly, Pierre; Misson, Benjamin; Perrière, Fanny; Bonnemoy, Frédérique; Joly, Muriel; Donnadieu-Bernard, Florence; Aguer, Jean-Pierre; Bohatier, Jacques; Mallet, Clarisse


    Soil phototrophic microorganisms, contributors to soil health and food webs, share their particular metabolism with plants. Current agricultural practices employ mixtures of pesticides to ensure the crops yields and can potentially impair these non-target organisms. However despite this environmental reality, studies dealing the susceptibility of phototrophic microorganisms to pesticide mixtures are scarce. We designed a 3 months microcosm study to assess the ecotoxicity of realistic herbicide mixtures of formulated S-metolachlor (Dual Gold Safeneur(®)), mesotrione (Callisto(®)) and nicosulfuron (Milagro(®)) on phototrophic communities of two soils (Limagne vertisol and Versailles luvisol). The soils presented different colonizing communities, with diatoms and chlorophyceae dominating communities in Limagne soil and cyanobacteria and bryophyta communities in Versailles soil. The results highlighted the strong impairment of Dual Gold Safeneur(®) treated microcosms on the biomass and the composition of both soil phototrophic communities, with no resilience after a delay of 3 months. This study also excluded any significant mixture effect on these organisms for Callisto(®) and Milagro(®) herbicides. We strongly recommend carrying on extensive soil studies on S-metolachlor and its commercial formulations, in order to reconsider its use from an ecotoxicological point of view.

  7. Selective isolation of potentially phosphate-mobilizing, biosurfactant-producing and biodegradative bacteria associated with a sub-Arctic, terricolous lichen, Peltigera membranacea. (United States)

    Sigurbjörnsdóttir, Margrét Auður; Vilhelmsson, Oddur


    Lichens are the symbiotic association of fungi and a photosynthetic partner. However, non-phototrophic bacteria are also present and thought to comprise an essential part of the lichen symbiosis, although their roles in the symbiosis are still poorly understood. In this study, we isolated and characterized 110 non-phototrophic bacterial lichen associates from thalli of the terricolous lichen Peltigera membranacea The biodegradative and other nutrient-scavenging properties studied among selected isolates were phosphate mobilization, biosurfactant production and degradation of napthalene and several biopolymers, suggesting organic and inorganic nutrient scavenging as roles for bacteria in the lichen symbiotic association. Identification by partial 16S rRNA gene sequencing revealed that the isolates comprised 18 genera within the Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes, many with high similarities with bacteria typically associated with the plant and rhizosphere environments, could suggest that plants may be important sources of terricolous lichen-associated bacteria, or vice versa.

  8. Phylogenetic and Metabolic Diversity of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming Bacteria in Strictly Anaerobic Mixed Cultures Enriched on RDX as Nitrogen Source (United States)


    the Enterobacteriaceae family ( Klebsiella pneumoniae, Serratia marcescens, Morganella morganii, Citrobacter freundii, and Escherichia coli) [10,11... wastewater to methane (70% of the total gas released). The following compounds were added to the basic salts and vitamins medium to enrich bacteria using RDX...RDX biodegradation by a methanogenic enrichment culture obtained from an explosives man- ufacturing wastewater treatment plant. Technical report, pp. 99

  9. Impact of fertilizing with raw or anaerobically digested sewage sludge on the abundance of antibiotic-resistant coliforms, antibiotic resistance genes, and pathogenic bacteria in soil and on vegetables at harvest. (United States)

    Rahube, Teddie O; Marti, Romain; Scott, Andrew; Tien, Yuan-Ching; Murray, Roger; Sabourin, Lyne; Zhang, Yun; Duenk, Peter; Lapen, David R; Topp, Edward


    The consumption of crops fertilized with human waste represents a potential route of exposure to antibiotic-resistant fecal bacteria. The present study evaluated the abundance of bacteria and antibiotic resistance genes by using both culture-dependent and molecular methods. Various vegetables (lettuce, carrots, radish, and tomatoes) were sown into field plots fertilized inorganically or with class B biosolids or untreated municipal sewage sludge and harvested when of marketable quality. Analysis of viable pathogenic bacteria or antibiotic-resistant coliform bacteria by plate counts did not reveal significant treatment effects of fertilization with class B biosolids or untreated sewage sludge on the vegetables. Numerous targeted genes associated with antibiotic resistance and mobile genetic elements were detected by PCR in soil and on vegetables at harvest from plots that received no organic amendment. However, in the season of application, vegetables harvested from plots treated with either material carried gene targets not detected in the absence of amendment. Several gene targets evaluated by using quantitative PCR (qPCR) were considerably more abundant on vegetables harvested from sewage sludge-treated plots than on vegetables from control plots in the season of application, whereas vegetables harvested the following year revealed no treatment effect. Overall, the results of the present study suggest that producing vegetable crops in ground fertilized with human waste without appropriate delay or pretreatment will result in an additional burden of antibiotic resistance genes on harvested crops. Managing human exposure to antibiotic resistance genes carried in human waste must be undertaken through judicious agricultural practice.

  10. Anaerobic Digestion Foaming Causes


    Ganidi, Nafsika


    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...


    Directory of Open Access Journals (Sweden)



    Full Text Available BACKGROUND Isolation of an anaerobe is usually neglected in hospitals with limited resources due to the expensive and complicated technique of anaerobic isolation methods, which is difficult to arrange in such resource poor settings. Conventionally adopted anaerobic culture methods such as Anaerobic jar, Gas-Pak, Anoxomat or Automated glove-box systems are extremely costly and cumbersome for single unit testing, but not suitable for small scale laboratories. However, anaerobic bacteria are not to be overlooked as they have made a comeback in clinical settings and are even showing resistance to Metronidazole, once thought to be the gold standard bullet against anaerobes. Deep seated pressure ulcers are usually the site where anaerobe causes an infection in synergy with aerobes. AIMS AND OBJECTIVES Isolation of anaerobes in deep seated pressure ulcers using a novel innovative technique and to study their antibiogram profile. MATERIALS AND METHODS Swabs taken from depth of deep seated pressure ulcers were immediately inoculated in Brucella blood agar at bedside and placed in polycarbonate airtight jar for anaerobic incubation using a novel innovative Modified Candle Jar technique. In this technique five grams of grease-free grade zero steel wool were dipped in 50ml freshly prepared acidified copper sulphate solution until the copper colour appeared. Excess solution was drained and the steel wool was moulded into a loose pad to fit on an open Petri plate placed on top of the inoculated Brucella blood agar plates. A white-wax candle was placed at the centre of this plate. A small test tube containing mixture of 0.5g sodium-bicarbonate and 0.5g magnesium carbonate was kept ready to be placed inside the jar, just after placing the inoculated plate and incubated for 48 hours. RESULTS Peptostreptococcus anaerobius and Bacteroides fragilis were successfully isolated from deep seated pressure ulcers by this method. Antibiogram studies were done using the

  12. Arsenic, Anaerobes, and Astrobiology (United States)

    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.


    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

  13. Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors (United States)

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na


    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. PMID:24672798

  14. Tar water digestion in an upflow anaerobic sludge blanket reactor

    Energy Technology Data Exchange (ETDEWEB)

    Skibsted Mogensen, A.; Angelidaki, I.; Schmidt, J.E.; Ahring, B.K. [Technical Univ., Dept. of Environmental Science and Engineering, Lyngby (Denmark)


    The water from the gasification and wet oxidised tar water has been digested anaerobically in UASB reactors and were digested in respectively 10 and 50% in batches. Though the tar water show inhibition at very low concentrations to aerobic microorganisms, the granular sludge used in UASB reactors degrades tar water in concentrations that reveal total inhibition of e.g. bacteria conducting the nitrification process. The value of waste waters are determined, showing that the tar water produces more biogas in the anaerobic digestion. A wide range of xenobiotics, especially phenolic compounds can be transformed in the anaerobic digestion process. Seven phenolic are followed in batch experiments and UASB reactor experiments, and their particular fate in the anaerobic systems embody large differences in the transformation pattern. (au) 24 refs.

  15. Feeding by phototrophic red-tide dinoflagellates on the ubiquitous marine diatom Skeletonema costatum. (United States)

    Du Yoo, Yeong; Jeong, Hae Jin; Kim, Mi Seon; Kang, Nam Seon; Song, Jae Yoon; Shin, Woongghi; Kim, Kwang Young; Lee, Kitack


    We investigated feeding by phototrophic red-tide dinoflagellates on the ubiquitous diatom Skeletonema costatum to explore whether dinoflagellates are able to feed on S. costatum, inside the protoplasm of target dinoflagellate cells observed under compound microscope, confocal microscope, epifluorescence microscope, and transmission electron microscope (TEM) after adding living and fluorescently labeled S. costatum (FLSc). To explore effects of dinoflagellate predator size on ingestion rates of S. costatum, we measured ingestion rates of seven dinoflagellates at a single prey concentration. In addition, we measured ingestion rates of the common phototrophic dinoflagellates Prorocentrum micans and Gonyaulax polygramma on S. costatum as a function of prey concentration. We calculated grazing coefficients by combining field data on abundances of P. micans and G. polygramma on co-occurring S. costatum with laboratory data on ingestion rates obtained in the present study. All phototrophic dinoflagellate predators tested (i.e. Akashiwo sanguinea, Amphidinium carterae, Alexandrium catenella, Alexandrium tamarense, Cochlodinium polykrikoides, G. polygramma, Gymnodinium catenatum, Gymnodinium impudicum, Heterocapsa rotundata, Heterocapsa triquetra, Lingulodinium polyedrum, Prorocentrum donghaiense, P. micans, Prorocentrum minimum, Prorocentrum triestinum, and Scrippsiella trochoidea) were able to ingest S. costatum. When mean prey concentrations were 170-260 ng C/ml (i.e. 6,500-10,000 cells/ml), the ingestion rates of G. polygramma, H. rotundata, H. triquetra, L. polyedrum, P. donghaiense, P. micans, and P. triestinum on S. costatum (0.007-0.081 ng C/dinoflagellate/d [0.2-3.0 cells/dinoflagellate/d]) were positively correlated with predator size. With increasing mean prey concentration of ca 1-3,440 ng C/ml (40-132,200 cells/ml), the ingestion rates of P. micans and G. polygramma on S. costatum continuously increased. At the given prey concentrations, the maximum ingestion

  16. Prospective study of the clinical performance of three BACTEC media in a modern emergency department: Plus Aerobic/F, Plus Anaerobic/F, and Anaerobic Lytic/F. (United States)

    Rocchetti, Andrea; Di Matteo, Luigi; Bottino, Paolo; Foret, Benjamin; Gamalero, Elisa; Calabresi, Alessandra; Guido, Gianluca; Casagranda, Ivo


    The performance of 3 blood culture bottles (BACTEC Plus Aerobic/F, Plus Anaerobic/F, and Anaerobic Lytic/F) were analyzed with clinical specimens collected from 688 Emergency Department patients. A total of 270 strains belonging to 33 species were identified, with E. coli and S. aureus as the most frequently detected. Overall recovery rate (RR) of bacteria and yeast was equivalent in the Plus Aerobic/F vials (208 of 270 isolates; 77.0%) and Anaerobic Lytic/F vials (206 isolates; 76.3%) and significantly better than in the Plus Anaerobic/F vials (189 isolates; 70.0%). Median time to detection (TTD) was earliest with the Anaerobic Lytic/F vials (12.0h) compared with the Plus Aerobic/F (14.6h) and Plus Anaerobic/F vials (15.4h). Positivity rate (PR) was similar for Anaerobic Lytic/F vials (76.9%) and Plus Aerobic/F vials (76.5%), but better if compared with Plus Anaerobic/F vials (69.4%). The PR and TTD for the combination of Plus Aerobic/F with Anaerobic Lytic/F (94.5% and 12.3h, respectively) was significantly better than with Plus Aerobic/F with Plus Anaerobic/F (87.8% and 14.1h).

  17. Variation of EPS,enzyme activity,and bacteria density in sewage sludge during the anaerobic/aerobic digestion processes by ultrasonic sludge treatment%超声波-缺氧/好氧消化过程污泥EPS、酶活性及菌落数的变化研究

    Institute of Scientific and Technical Information of China (English)

    姚炜婷; 孙水裕; 郑莉; 尹光彩; 李楚华; 蔡明山; 许燕滨; 童文锦


    In order to investigate the sludge anaerobic/aerobic digestion mechanism by ultrasonic sludge treatment,the index proportion of EPS and dissolved substances(polysaccharides,protein and DNA),enzyme activities(protease activity and dehydorgenase activity) were measured in the anaerobic/aerobic digestion by the optimal ultrasonic treatment(28 kHz ultrasonic frequency,0.1 W·mL-1 ultrasonic density,15 min ultrasonic time and 12 h ultrasonic interval time).It showed that the performances of anaerobic/aerobic digestion were greatly improved by ultrasonic treatment,with the removal rate of VSS reaching 40.14% after digestion for 10 days,20% more than that of the controlled,and at the same time great amount of soluble organics was released.The index proportions of EPS and dissolved substances in the ultrasonic sludge and the control were almost the same,indicating that ultrasonic could promote oxygen/aerobic sludge digestion but would not change the index proportion of EPS and their dissolved substances.The variation trend of enzyme activities increased at the beginning and then dropped off after 10 days' digestion,with the maximum value appearing on the fourth day.The protease activity of ultrasonic sludge was more than that of the controlled during 0~5 d digestion,due to the markedly improved protease activity and the high-speed biological reaction.Organic matter degradation ratio was also improved greatly,leading to the improved VSS removal rate in ultrasonic sludge.While the variation of dehydrogenase activity in ultrasonic sludge was almost the same compared with the controlled,it was therefore unable to represent ultrasonic promotion by sludge anaerobic/aerobic digestibility.The variation trend of sludge bacteria density also increased at the beginning and then dropped off after 10 days' digestion,but it is controversial for the measurement of bacteria density.Further study is needed.%为研究超声波促进污泥缺氧/好氧消化的机理,采用

  18. Extremely 'vanadiphilic' multiply metal-resistant and halophilic aerobic anoxygenic phototrophs, strains EG13 and EG8, from hypersaline springs in Canada. (United States)

    Csotonyi, J T; Maltman, C; Swiderski, J; Stackebrandt, E; Yurkov, V


    Two pinkish peach-colored strains of obligately aerobic phototrophic bacteria, EG13 and EG8, were isolated from a saline spring effluent stream in west central Manitoba, Canada. The strains possessed bacteriochlorophyll a incorporated into a typical purple bacterial light-harvesting complex 1 (870 nm) and reaction center (801 nm). Analysis of 16S rRNA gene sequences indicated 100% identity among the isolates and 99% similarity to Roseovarius tolerans EL-172(T). The strains were physiologically well adapted to high salinity (0-22%), fluctuating pH (7-12) and temperature (7-40 °C) of the exposed hypersaline stream of East German Creek. EG8 and EG13 were also highly resistant to the toxic metal(loid) oxyanions tellurite, selenite and metavanadate (≥1000 μg/ml each). Most intriguingly, growth and pigment production of EG13 on glutamate minimal medium was stimulated by 1000-10000 μg/ml of sodium metavanadate compared to metal-free conditions. Phylogenetic analysis and phenotypic properties such as pigment composition and morphology indicate close relatedness to Roseovarius genus.

  19. Pathways and bioenergetics of anaerobic carbon monoxide fermentation

    NARCIS (Netherlands)

    Diender, Martijn; Stams, Fons; Machado de Sousa, Diana


    Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the poten

  20. Comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin® and the Hawaiian marine algae, Chaetoceros, for potential broad-spectrum control of anaerobically grown lactic acid bacteria. (United States)

    Božic, Aleksandar K; Anderson, Robin C; Ricke, Steven C; Crandall, Philip G; O'Bryan, Corliss A


    The gastrointestinal tract of bovines often contains bacteria that contribute to disorders of the rumen, and may also contain foodborne or opportunistic human pathogens as well as bacteria capable of causing mastitis in cows. Thus there is a need to develop broad-spectrum therapies that are effective while not leading to unacceptably long antibiotic withdrawal times. The effects of the CH(4)-inhibitors nitroethane (2 mg/mL), 2-nitro-1-propanol (2 mg/mL), lauric acid (5 mg/mL), the commercial product Lauricidin® (5 mg/mL), and a finely ground product of the Hawaiian marine algae, Chaetoceros (10 mg/mL), were compared in pure cultures of Streptococcus agalactia, Enterococcus faecium, Streptococcus bovis, and in a mixed lactic acid rumen bacterial culture. Lauricidin® and lauric acid exhibited the most bactericidal acidity against all bacteria. These results suggest potential animal health benefits from supplementing cattle diets with lauric acid or Lauricidin® to improve the health of the rumen and help prevent shedding of human pathogens.

  1. A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria. (United States)

    Abbasian, Firouz; Lockington, Robin; Mallavarapu, Megharaj; Naidu, Ravi


    Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.

  2. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen


    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  3. The Epsomitic Phototrophic Microbial Mat of Hot Lake, Washington. Community Structural Responses to Seasonal Cycling

    Energy Technology Data Exchange (ETDEWEB)

    Lindemann, Stephen R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moran, James J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stegen, James C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Renslow, Ryan S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cole, Jessica K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dohnalkova, Alice [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tremblay, Julien [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singh, Kanwar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Malfatti, Stephanie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Feng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beyenal, Haluk [Washington State Univ., Pullman, WA (United States); Fredrickson, Jim K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Phototrophic microbial mats are compact ecosystems composed of highly interactive organisms in which energy and element cycling take place over millimeter-to-centimeter-scale distances. Although microbial mats are common in hypersaline environments, they have not been extensively characterized in systems dominated by divalent ions. Hot Lake is a meromictic, epsomitic lake that occupies a small, endorheic basin in north-central Washington. The lake harbors a benthic, phototrophic mat that assembles each spring, disassembles each fall, and is subject to greater than tenfold variation in salinity (primarily Mg2+ and SO2-4) and irradiation over the annual cycle. We examined spatiotemporal variation in the mat community at five time points throughout the annual cycle with respect to prevailing physicochemical parameters by amplicon sequencing of the V4 region of the 16S rRNA gene coupled to near-full-length 16S RNA clone sequences. The composition of these microbial communities was relatively stable over the seasonal cycle and included dominant populations of Cyanobacteria, primarily a group IV cyanobacterium (Leptolyngbya), and Alphaproteobacteria (specifically, members of Rhodobacteraceae and Geminicoccus). Members of Gammaproteobacteria (e.g., Thioalkalivibrio and Halochromatium) and Deltaproteobacteria (e.g., Desulfofustis) that are likely to be involved in sulfur cycling peaked in summer and declined significantly by mid-fall, mirroring larger trends in mat community richness and evenness. Phylogenetic turnover analysis of abundant phylotypes employing environmental metadata suggests that seasonal shifts in light variability exert a dominant influence on the composition of Hot Lake microbial mat communities. The seasonal development and organization of these structured microbial mats provide opportunities for analysis of the temporal and physical dynamics that feed back to community function.

  4. The diversity of cyanobacterial metabolism: genome analysis of multiple phototrophic microorganisms

    Directory of Open Access Journals (Sweden)

    Beck Christian


    Full Text Available Abstract Background Cyanobacteria are among the most abundant organisms on Earth and represent one of the oldest and most widespread clades known in modern phylogenetics. As the only known prokaryotes capable of oxygenic photosynthesis, cyanobacteria are considered to be a promising resource for renewable fuels and natural products. Our efforts to harness the sun's energy using cyanobacteria would greatly benefit from an increased understanding of the genomic diversity across multiple cyanobacterial strains. In this respect, the advent of novel sequencing techniques and the availability of several cyanobacterial genomes offers new opportunities for understanding microbial diversity and metabolic organization and evolution in diverse environments. Results Here, we report a whole genome comparison of multiple phototrophic cyanobacteria. We describe genetic diversity found within cyanobacterial genomes, specifically with respect to metabolic functionality. Our results are based on pair-wise comparison of protein sequences and concomitant construction of clusters of likely ortholog genes. We differentiate between core, shared and unique genes and show that the majority of genes are associated with a single genome. In contrast, genes with metabolic function are strongly overrepresented within the core genome that is common to all considered strains. The analysis of metabolic diversity within core carbon metabolism reveals parts of the metabolic networks that are highly conserved, as well as highly fragmented pathways. Conclusions Our results have direct implications for resource allocation and further sequencing projects. It can be extrapolated that the number of newly identified genes still significantly increases with increasing number of new sequenced genomes. Furthermore, genome analysis of multiple phototrophic strains allows us to obtain a detailed picture of metabolic diversity that can serve as a starting point for biotechnological

  5. The Epsomitic Phototrophic Microbial Mat of Hot Lake, Washington: Community Structural Responses to Seasonal Cycling

    Directory of Open Access Journals (Sweden)

    Stephen R Lindemann


    Full Text Available Phototrophic microbial mats are compact ecosystems composed of highly interactive organisms in which energy and element cycling take place over millimeter-to-centimeter-scale distances. Although microbial mats are common in hypersaline environments, they have not been extensively characterized in systems dominated by divalent ions. Hot Lake is a meromictic, epsomitic lake that occupies a small, endorheic basin in north-central Washington. The lake harbors a benthic, phototrophic mat that assembles each spring and disassembles each fall and is subject to greater than tenfold variation in salinity (primarily Mg2+ and SO42- and irradiation over the annual cycle. We examined spatiotemporal variation in the mat community at five time points throughout the annual cycle with respect to prevailing physicochemical parameters by sequencing the V4 region of the 16S rRNA gene coupled to near-full-length 16S RNA clone sequences. The composition of these microbial communities was relatively stable over the seasonal cycle and included dominant populations of Cyanobacteria, primarily a group IV cyanobacterium (Leptolyngbya, and Alphaproteobacteria (specifically, members of Rhodobacteraceae and Geminicoccus. Members of Gammaproteobacteria (e.g., Thioalkalivibrio and Halochromatium and Deltaproteobacteria (e.g., Desulfofustis that are likely to be involved in sulfur cycling peaked in summer and declined significantly by mid-fall, mirroring larger trends in mat community richness and evenness. Phylogenetic turnover analysis of abundant phylotypes employing environmental metadata suggests that seasonal shifts in light variability exert a dominant influence on the composition of Hot Lake microbial mat communities. The seasonal development and organization of these structured microbial mats provide opportunities for analysis of the temporal and physical dynamics that feed back to community function.

  6. Regulation of electron transfer processes affects phototrophic mat structure and activity

    Directory of Open Access Journals (Sweden)

    Haluk eBeyenal


    Full Text Available Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA. We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl (cathodic mat system and +300 mVAg/AgCl (anodic mat system and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both anodic and cathodic mat systems. Interestingly, the cathodic mats generated the highest reducing current at the same time points that the anodic mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the cathodic mats than in the anodic mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the cathodic mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that

  7. Combined anaerobic ammonium and methane oxidation for nitrogen and methane removal. (United States)

    Zhu, Baoli; Sánchez, Jaime; van Alen, Theo A; Sanabria, Janeth; Jetten, Mike S M; Ettwig, Katharina F; Kartal, Boran


    Anammox (anaerobic ammonium oxidation) is an environment-friendly and cost-efficient nitrogen-removal process currently applied to high-ammonium-loaded wastewaters such as anaerobic digester effluents. In these wastewaters, dissolved methane is also present and should be removed to prevent greenhouse gas emissions into the environment. Potentially, another recently discovered microbial pathway, n-damo (nitrite-dependent anaerobic methane oxidation) could be used for this purpose. In the present paper, we explore the feasibility of simultaneously removing methane and ammonium anaerobically, starting with granules from a full-scale anammox bioreactor. We describe the development of a co-culture of anammox and n-damo bacteria using a medium containing methane, ammonium and nitrite. The results are discussed in the context of other recent studies on the application of anaerobic methane- and ammonia-oxidizing bacteria for wastewater treatment.

  8. Research Progress on Microbial Properties of Nitrite-Dependent Anaerobic Methane-Oxidising Bacteria%亚硝酸盐型甲烷厌氧氧化微生物特性研究进展

    Institute of Scientific and Technical Information of China (English)



    亚硝酸盐型甲烷厌氧氧化( nitrite-dependent anaerobic methane oxidation, N-DAMO)是新近发现的生物反应,是偶联碳氮循环的关键环节,是环境领域和微生物领域的重大发现. N-DAMO的发现对于完善碳氮生物地球化学循环、丰富微生物学内容和研发新型生物脱氮除碳工艺均具有巨大的推动作用.催化N-DAMO反应的微生物为Candidatus Methylomirabilis oxyfera ( M. oxyfera),其隶属于一新发现的细菌门———NC10门.近年来,M. oxyfera的生物学研究取得了许多突破性进展,如初步探明了其个体形态特征、细胞化学组分特征、富集培养特征、生理生化特征及生态学特征,最突出的例子包括发现了M. oxyfera独特的细胞(星状)形态及特殊的脂肪酸(10MeC16:1△7)组分等.最近,N-DAMO的机制研究方面也有了突破性进展:发现了地球上第4种生物产氧途径.目前认为,M. oxyfera具有内产氧功能,其首先将NO2-还原为NO,然后将2分子NO进行歧化反应生成N2和O2,最后利用生成的O2对甲烷进行氧化.本文系统地介绍了M. oxyfera各方面的微生物特性.%Nitrite-dependent anaerobic methane oxidation ( N-DAMO ) is a recently discovered process that constitutes a unique association between the two major global elements essential for life, carbon and nitrogen. This process is one of the most important discoveries in the fields of environmental science and microbiology. The discovery of N-DAMO process supplements biogeochemical cycles of carbon and nitrogen in nature, extends microbial diversity and urges development of novel simultaneous carbon and nitrogen removal process. The N-DAMO process is mediated by the bacterium “Candidatus Methylomirabilis oxyfera” (M. oxyfera), which belongs to the candidate phylum NC10. Currently, a series of breakthroughs have been made in the research of M. oxyfera. The properties of M. oxyfera morphology, chemical composition, enrichment culture

  9. Investigations on the inactivation of selected bacteria and viruses during mesophilic and thermophilic anaerobic alkaline cofermentation of biological waste materials, food residues and other animal residues; Seuchenhygienische Untersuchungen zur Inaktivierung ausgewaehlter Bakterien und Viren bei der mesophilen und thermophilen anaeroben alkalischen Faulung von Bio- und Kuechenabfaellen sowie anderen Rest- und Abfallstoffen tierischer Herkunft

    Energy Technology Data Exchange (ETDEWEB)

    Hoferer, M. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Umwelt- und Tierhygiene sowie Tiermedizin mit Tierklinik


    The purpose of this study is to investigate the inactivation kinetics of a number of different bacteria (Salmonella Senftenberg, Escherichia coli O157, Enterococcus faecium) and viruses (Bovine Enterovirus (ECBO), Equine Rhinovirus (ERV), Poliovirus, Bovine Parvovirus (BPV)) during the process of anaerobic cofermentation. Experiments were conducted in a semi-technical biogas plant at the University of Hohenheim. The fermenter was fed with a mixture of slurry from pigs or cattle (75%) and leftovers (25%) and was run under mesophilic (30 C + 35 C) as well as under thermophilic temperature conditions (50 C + 55 C). Volume and filter-sandwich germ-carriers were specifically developed and/or optimised for these analyses. Parallel to the experiments at the University of Hohenheim and under almost identical process conditions, various viruses (African Swine Fever Virus, Pseudorabies Virus, Classical Swine Fever Virus, Foot and Mouth Disease Virus, Swine Vesicular Disease Virus) were examined at the Federal Research Centre for Virus Diseases of Animals in Tuebingen. The results obtained at each research institution are directly compared. (orig.)

  10. 一个硫酸盐还原细菌富集物对丁草胺的厌氧降解%Anaerobic degradation of butachlor by sulfate-reducing bacteria enrichment culture

    Institute of Scientific and Technical Information of China (English)

    叶央芳; 杜宇峰


    An enrichment culture of sulfate-reducing bacteria,capable of anaerabic degrading butachlor,was obtained.The degradation kinetics of butachlor by the enrichment culture was determined and the optimum concentration of butachlor,the optimum pH and temperature for degradation of butachlor were observed..%通过多次富集培养,得到一个能有效厌氧降解丁草胺的硫酸盐还原细菌(SRB)富集物,并对该富集物的生长动力学以及生长的最适丁草胺浓度、最适pH和最适温度作了探讨.

  11. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.


    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  12. 1株高温型厌氧产氢细菌的分离与鉴定%Isolation and Identification of an Anaerobic Bacteria with Thermophilic Hydrogen Production

    Institute of Scientific and Technical Information of China (English)

    王娜; 肖军; 肇莹; 王红; 陈珣; 龚娜; 杨涛


    Eight stains were isolated from racks in oilfield by the way of interlayer culture and anaerobic bottle. Two strains could produce hydrogen detected by gas chromatograph and ability. ZX-1 strain had the highest yield of hydrogen which was l.Smol H2-mor' glucose at 60^. It was 0.35fjLm~0.45u.mx2n,m-8|Ain, bacilliform sharp without flagellum, gram-negative and with spore. The colonies of ZX-1 were round, creamy, ganoid, opaque. They had smooth surface, not transparent. The results of physiological biochemical test showed that gelatin liquefaction, nitrate reduction test, citrate utilization and glucose were positive, and oxidase reaction, starch hydrolysis and VP reaction were negative. The result of comparing its 16S rDNA sequence with known seguence showed that it was identified as Brevibacillus borsieleruis.%利用平面夹层和平板培养瓶厌氧法从油田区的岩石中分离到8株细菌,经气体组成及产氢能力检测,发现其中2株细菌具有产氢能力.在60℃高温条件下,菌株ZX-1的氢转化率最高,为1.8mol H2·mol-1葡萄糖.该菌为革兰氏阴性、杆菌、有芽孢、无鞭毛,菌体大小为(0.35 -0.45) μm× (2~8)μm;菌落特征表现为圆形、乳白色、表面光滑、不透明;生理生化试验结果表明,明胶液化、硝酸盐还原、柠檬酸盐利用、葡萄糖为阳性,氧化酶、淀粉水解、V-P反应为阴性,初步鉴定为短芽孢杆菌属(Brevibacillus).经16S rDNA PCR扩增及测序结果表明,该菌序列与Brevibacillus borstelensis的序列相似性达100%,进一步确定该菌为波茨坦短芽孢杆菌.

  13. Molecular analysis of the biomass of a fluidized bed reactor treating synthetic vinasse at anaerobic and micro-aerobic conditions

    NARCIS (Netherlands)

    Rodriguez, E.; Lopes, A.; Fdz-Polanco, M.; Stams, A.J.M.; Garcia Encina, P.A.


    The microbial communities (Bacteria and Archaea) established in an anaerobic fluidized bed reactor used to treat synthetic vinasse (betaine, glucose, acetate, propionate, and butyrate) were characterized by denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis. This study was focu

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

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


    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.

  15. Anaerobic Nitrogen Fixers on Mars (United States)

    Lewis, B. G.


    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.

  16. SAR11 bacteria linked to ocean anoxia and nitrogen loss

    DEFF Research Database (Denmark)

    Tsementzi, Despina; Wu, Jieying; Deutsch, Samuel;


    Bacteria of the SAR11 clade constitute up to one half of all microbial cells in the oxygen-rich surface ocean. SAR11 bacteria are also abundant in oxygen minimum zones (OMZs), where oxygen falls below detection and anaerobic microbes have vital roles in converting bioavailable nitrogen to N2 gas....... Anaerobic metabolism has not yet been observed in SAR11, and it remains unknown how these bacteria contribute to OMZ biogeochemical cycling. Here, genomic analysis of single cells from the world’s largest OMZ revealed previously uncharacterized SAR11 lineages with adaptations for life without oxygen...

  17. Cenoses of phototrophic algae of ultrasaline lakes in the Kulunda steppe (Altai krai, Russian Federation) (United States)

    Sapozhnikov, Ph. V.; Kalinina, O. Yu.; Nikitin, M. A.; Samylina, O. S.


    In 2012, expeditions of the Institute of Microbiology, Russian Academy of Sciences, delivered samples of algo-bacterial mats from Kulunda steppe alkaline lakes (Petukhovskoe alkaline lake, Tanatar VI, and Gorchina III). The filamentous alga Ctenocladus circinnatus (Chlorophyta) acted as an edificator of the mats. The composition of cenoses algocomponents also included chlorophytes Dunaliella viridis and Picocystis salinarum as well as diatoms Anomeoneis sphaerophora, Brachysira brebissonii, B. zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, N. cf. communis, and Nitzschia sp. 1. The composition and structure of phototrophic algae cenoses (including diatom taxocenes) were described for the investigated lakes for the first time. For the period from 2011 to 2012, the total mineralization significantly increased in lakes. This involved sensible alterations of cenoses. B. zellensis was the most permanent component of diatom taxocenes in both seasons. In the summer of 2011, it was often accompanied by A. sphaerophora and B. brebissonii. In the summer of 2012, A. sphaerophora was found only singularly in Lake Gorchina III, and some biotopes of Lake Tanatar VI were massively inhabited by N. cf. communis, including colonies that had not been previously described for the species. The genetic analysis of three diatoms, which are markedly different from each other in their appearance and were sampled from different lakes but were all determined as Nitzschia cf. communis, showed their complete similarity to each other with the 18S rRNA gene fragment and the highest similarity of all the three diatoms with the species Nitzschia communis.

  18. Photorespiration and Rate Synchronization in a Phototroph-Heterotroph Microbial Consortium

    Directory of Open Access Journals (Sweden)

    Fadoua El Moustaid


    Full Text Available Theprocessofoxygenicphotosynthesisisrobustandubiquitous,relyingcentrallyoninput of light, carbon dioxide, and water, which in many environments are all abundantly available, and from which are produced, principally, oxygen and reduced organic carbon. However, photosynthetic machinery can be conflicted by the simultaneous presence of carbon dioxide and oxygen through a process sometimes called photorespiration. We present here a model of phototrophy, including competition for RuBisCO binding sites between oxygen and carbon dioxide, in a chemostat-based microbial population. The model connects to the idea of metabolic pathways to track carbon and degree of reduction through the system. We find decomposition of kinetics into elementary flux modes a mathematically natural way to study synchronization of mismatched rates of photon input and chemostat turnover. In the single species case, though total biomass is reduced by photorespiration, protection from excess light exposures and its consequences (oxidative and redox stress may result. We also find the possibility that a consortium of phototrophs with heterotrophs can recycle photorespiration byproduct into increased biomass at the cost of increase in oxidative product (here, oxygen.

  19. Hydrologic variability affects invertebrate grazing on phototrophic biofilms in stream microcosms.

    Directory of Open Access Journals (Sweden)

    Serena Ceola

    Full Text Available The temporal variability of streamflow is known to be a key feature structuring and controlling fluvial ecological communities and ecosystem processes. Although alterations of streamflow regime due to habitat fragmentation or other anthropogenic factors are ubiquitous, a quantitative understanding of their implications on ecosystem structure and function is far from complete. Here, by experimenting with two contrasting flow regimes in stream microcosms, we provide a novel mechanistic explanation for how fluctuating flow regimes may affect grazing of phototrophic biofilms (i.e., periphyton by an invertebrate species (Ecdyonurus sp.. In both flow regimes light availability was manipulated as a control on autotroph biofilm productivity and grazer activity, thereby allowing the test of flow regime effects across various ratios of biofilm biomass to grazing activity. Average grazing rates were significantly enhanced under variable flow conditions and this effect was highest at intermediate light availability. Our results suggest that stochastic flow regimes, characterised by suitable fluctuations and temporal persistence, may offer increased windows of opportunity for grazing under favourable shear stress conditions. This bears important implications for the development of comprehensive schemes for water resources management and for the understanding of trophic carbon transfer in stream food webs.

  20. Development of Synechocystis sp. PCC 6803 as a Phototrophic Cell Factory

    Directory of Open Access Journals (Sweden)

    Fuzhong Zhang


    Full Text Available Cyanobacteria (blue-green algae play profound roles in ecology and biogeochemistry. One model cyanobacterial species is the unicellular cyanobacterium Synechocystis sp. PCC 6803. This species is highly amenable to genetic modification. Its genome has been sequenced and many systems biology and molecular biology tools are available to study this bacterium. Recently, researchers have put significant efforts into understanding and engineering this bacterium to produce chemicals and biofuels from sunlight and CO2. To demonstrate our perspective on the application of this cyanobacterium as a photosynthesis-based chassis, we summarize the recent research on Synechocystis 6803 by focusing on five topics: rate-limiting factors for cell cultivation; molecular tools for genetic modifications; high-throughput system biology for genome wide analysis; metabolic modeling for physiological prediction and rational metabolic engineering; and applications in producing diverse chemicals. We also discuss the particular challenges for systems analysis and engineering applications of this microorganism, including precise characterization of versatile cell metabolism, improvement of product rates and titers, bioprocess scale-up, and product recovery. Although much progress has been achieved in the development of Synechocystis 6803 as a phototrophic cell factory, the biotechnology for “Compounds from Synechocystis” is still significantly lagging behind those for heterotrophic microbes (e.g., Escherichia coli.

  1. Rhodobacter changlensis sp. nov., a psychrotolerant, phototrophic alphaproteobacterium from the Himalayas of India. (United States)

    Anil Kumar, P; Srinivas, T N R; Sasikala, Ch; Ramana, Ch V


    A Gram-negative, non-motile, oval to rod-shaped, psychrotolerant, phototrophic, purple non-sulfur bacterium (designated strain JA139T) was isolated from a snow sample from Changla Pass in the Indian Himalayas. Strain JA139T had vesicular-type intracytoplasmic membrane structures and contained bacteriochlorophyll a and most probably spheroidene-like carotenoids. Biotin, niacin and thiamine were required for growth of strain JA139T. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that the strain clustered with species of the genus Rhodobacter but was distinctly separate from all recognized members of the family Rhodobacteraceae. Based on the genotypic and phenotypic differences observed between strain JA139T and recognized Rhodobacter species, strain JA139T is considered to represent a novel species of the genus, for which the name Rhodobacter changlensis sp. nov. is proposed. The type strain is JA139T (=DSM 18774T=CCUG 53722T=JCM 14338T).

  2. Rhodovastum atsumiense gen. nov., sp. nov., a phototrophic alphaproteobacterium isolated from paddy soil. (United States)

    Okamura, Keiko; Hisada, Takayoshi; Kanbe, Toshio; Hiraishi, Akira


    A photoorganotrophic alphaproteobacterium designated strain G2-11(T) was isolated from submerged paddy soil. This bacterium had relatively large, oval to rod-shaped cells (2.0-3.0x3.0-10 microm). Cells were motile by means of single polar flagella. The color of phototrophically growing cultures was reddish-brown. The cell extract had absorption maxima at 375, 465, 492, 529, 592, 804, and 844 nm, indicating the presence of bacteriochlorophyll a and carotenoides of the spirilloxanthin series. Vesicular intracytoplasmic membranes were present. The main component of cellular fatty acids was C(18:1)omega7c. Ubiquinone-10 and rhodoquinone-10 were the major quinones. A 16S rRNA gene sequence analysis revealed that the isolate is closest to the acidophilic aerobic photosynthetic bacterium Acidisphaera rubrifaciens strain HS-AP3(T) (93.3% similarity). The G+C content of genomic DNA is 67.8 mol%. The name Rhodovastum atsumiense gen. nov., sp. nov. is proposed for the novel isolate. The type strain is strain G2-11(T) (=NBRC 104268(T)=KCTC 5708(T)).

  3. Comparative evaluation of phototrophic microtiter plate cultivation against laboratory-scale photobioreactors. (United States)

    Morschett, Holger; Schiprowski, Danny; Rohde, Jannis; Wiechert, Wolfgang; Oldiges, Marco


    Extended cultivation times, rendering phototrophic bioprocess development time inefficient, resulted in the recent development of micro-photobioreactors enabling accelerated process development. However, especially for laboratory photobioreactors, only little is known concerning the influence of design on process performance. Thus, the aim of the present investigation was to evaluate the scalability of a microtiter plate-based parallelized micro-photobioreactor against a representative set of established laboratory photobioreactors. Lipid production by Chlorella vulgaris was used as a model system. During exponential growth, the microtiter plate cultures achieved maximal growth rates of ca. 1.44 ± 0.02 day(-1) being in good agreement with the larger systems. Moreover, cultures in the micro-photobioreactor could be kept in the exponential phase up to the highest biomass concentrations most probably due to the beneficial light supply at this scale. Compared to the shake flask and test tube cultures, microtiter plate cultivation achieved an equivalent biomass yield, lipid content, and lipid fingerprint. In contrast, the flat-panel process resulted only in marginal productivity due to insufficient light supply. Thus, microtiter plates showed good scalability to the investigated laboratory photobioreactors as overall differences were rather small taking the differing scales into account.

  4. Phototrophic periphyton techniques combine phosphorous removal and recovery for sustainable salt-soil zone. (United States)

    Lu, Haiying; Feng, Yanfang; Wu, Yonghong; Yang, Linzhang; Shao, Hongbo


    The P (Pi as KH2PO4 and Po as ATP) removal processes by phototrophic periphyton were investigated by determining the removal kinetics, metal content (Ca, Mg, Al, Fe, Cu, and Zn) of the solution and P fractions (Labile-P, Fe/Al-P, Ca-P, and Res-P) within the periphyton. Results showed that the periphyton was able to remove completely both Pi and Po after 48h when periphyton content was greater than 0.2gL(-1) (dry weight). The difference between Pi and Po removal was the conversion of Po into Pi by the periphyton, after that the removal mechanism was similar. The P removal mechanism was mainly due to the adsorption on the surfaces of the periphyton, including two aspects: i) the adsorption of PO4(3-) onto metal salts such as calcium carbonate (~50%) and ii) complexation between PO4(3-) and metal cations such as Ca(2+) (~40%). However, this bio-adsorptional process was significantly influenced by the extracellular polymeric substance (EPS) of periphyton, water hardness, initial P concentration, temperature and light intensity. This study not only deepens the understanding of P biogeochemical process in aquatic ecosystem, but provides a potential biomaterial for combining phosphorous removal and recovery from non-point source wastewaters, especially around salt-soil zone.

  5. My Lifelong Passion for Biochemistry and Anaerobic Microorganisms. (United States)

    Thauer, Rudolf Kurt


    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.

  6. Potential application of anaerobic extremophiles for hydrogen production (United States)

    Pikuta, Elena V.; Hoover, Richard B.


    In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data

  7. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;


    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...... requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader...

  8. Evidence for PAH Removal Coupled to the First Steps of Anaerobic Digestion in Sewage Sludge

    Directory of Open Access Journals (Sweden)

    Glenda Cea-Barcia


    Full Text Available Anaerobic degradation of polycyclic aromatic hydrocarbons has been brought to the fore, but information on removal kinetics and anaerobic degrading bacteria is still lacking. In order to explore the organic micropollutants removal kinetics under anaerobic conditions in regard to the methane production kinetics, the removal rate of 12 polycyclic aromatic hydrocarbons was measured in two anaerobic batch reactors series fed with a highly loaded secondary sludge as growth substrate. The results underscore that organic micropollutants removal is coupled to the initial stages of anaerobic digestion (acidogenesis and acetogenesis. In addition, the organic micropollutants kinetics suggest that the main removal mechanisms of these hydrophobic compounds are biodegradation and/or sequestration depending on the compounds.

  9. The influence of biofilm formation by Gardnerella vaginalis and other anaerobes on bacterial vaginosis


    Machado, António; Cerca, Nuno


    Bacterial vaginosis (BV) is the worldwide leading vaginal disorder in women of reproductive age. BV is characterized by the replacement of beneficial lactobacilli and the augmentation of anaerobic bacteria. Gardnerella vaginalis is a predominant bacterial species, however, BV is also associated with other numerous anaerobes, such as Atopobium vaginae, Mobiluncus mulieris, Prevotella bivia, Fusobacterium nucleatum and Peptoniphilus sp.. Currently, the role of G. vaginalis in the etiology of BV...

  10. Isolation and characterization of Bacillus thermophilic bacteria AT07-1 and its application in sludge solubilization and bio-hydrogen production by anaerobic fermentation%嗜热菌株AT07-1的分离鉴定及其在污泥溶解预处理厌氧发酵产氢中的应用

    Institute of Scientific and Technical Information of China (English)

    汤迎; 李小明; 杨永林; 杨麒; 曾光明; 郭亮; 朱小峰; 李焕利; 潘维


    A novel strain of thermophilic bacteria with high efficiency for sludge dissolution was isolated from garden soil by the method of dilution spread. The strain's colony morphology, physiological and biochemical characteristics were observed. Results showed that the strain was a small, Gram-positive, rod-shaped, spore-forming, aerobic or facultative aerobic bacterium. The strain grew optimally at 651 and pH 6. 8 ~7.5. The 16S rDNA analysis showed that the strain has not been previously reported and therefore it was labeled Bacillus thermophilic bacteria AT07-1 (registration number: FJ231108). The pure culture of the strain was then used in sludge solubilization tests ( S-TE tests) and an enhanced solubilization process was obtained. The volatile suspended solid ( VSS) solubilization rate reached 59.41% at 2.5 d after the inoculation, 25.58% higher than the process without it, which meets the standard of sludge stability suggested by the U. S. Environmental Protection Agency. Preliminary investigations on hydrogen production from anaerobic fermentation of sludge showed that bio-hydrogen production after pretreatment with Bacillus thermophilic bacteria AT07-lwas 26.4% higher than without it, and the biogas was only composed of hydrogen and carbon dioxide.%从湖南大学花园土壤中采集样品,用稀释涂布法分离和纯化适于污泥溶解的典型嗜热菌菌株,从中选出一株高效菌进行形态观察,并对其进行生理生化鉴定.结果表明,该菌株的革兰氏染色为阳性,呈细杆状,产芽孢,为好氧或兼性需氧细菌,最适生长温度为65℃,最适生长pH值为6.8~7.5.通过16SrDNA碱基测序和对比证实,该菌株是目前尚未报道过的一株嗜热菌,GenBank中注册命名为Bacillus thermophilic bacteria AT07-1(注册号:FJ231108).同时,将其纯种菌用于嗜热酶溶解(solubilization by thermophilic enzyme,S-TE)污泥稳定化处理,接种该嗜热菌可促进污泥中悬浮固体的溶解,2.5d时接种

  11. An alphaproteobacterium capable of both aerobic and anaerobic anoxygenic photosynthesis but incapable of photoautotrophy: Charonomicrobium ambiphototrophicum, gen. nov., sp. nov. (United States)

    Csotonyi, J T; Stackebrandt, E; Swiderski, J; Schumann, P; Yurkov, V


    A facultatively aerobic deep brown coccoid to ovoid bacterium, strain EG17(T), was isolated from a saline effluent stream in the NaCl-dominated brine spring system known as East German Creek in the province of Manitoba, Canada. The strain produced BChl a incorporated into a functional reaction center and two light-harvesting complexes with absorption peaks at 802, 850, and 879 nm. EG17(T) is the first reported anoxygenic phototroph capable of photoheterotrophic growth under both oxic and anoxic conditions. It yielded proportionally the greatest aerobic photosynthetic biomass under oligotrophic conditions. The results of 16S rRNA gene sequence comparisons revealed that EG17(T) was related most closely to the aerobic anoxygenic phototrophs Roseibacterium elongatum (98.3%) and quite distantly to both Dinoroseobacter shibae (95.2%) and Roseicyclus mahoneyensis (94.7%). The DNA G + C content was 65.6 mol%. On the basis of the unique dual aerobic/anaerobic photosynthetic capability, the distinctive spectrophotometric absorption of the photosynthetic apparatus, diagnostic physiological and biochemical traits, and the moderate phylogenetic separation between EG17(T) and its nearest relatives, it is concluded that this microorganism should be classified as a novel genus and species, Charonomicrobium ambiphototrophicum gen. nov., sp. nov., with EG17(T) as the type strain.

  12. Degradation of p-nitrophenol by the phototrophic bacterium Rhodobacter capsulatus. (United States)

    Roldán, M D; Blasco, R; Caballero, F J; Castillo, F


    The phototrophic bacterium Rhodobacter capsulatus detoxified p-nitrophenol and 4-nitrocatechol. The bacterium tolerated moderate concentrations of p-nitrophenol (up to 0.5 mM) and degraded it under light at an optimal O2 pressure of 20 kPa. The bacterium did not metabolize the xenobiotic in the dark or under strictly anoxic conditions or high O2 pressure. Bacterial growth with acetate in the presence of p-nitrophenol took place with the simultaneous release of nonstoichiometric amounts of 4-nitrocatechol, which can also be degraded by the bacterium. Crude extracts from R. capsulatus produced 4-nitrocatechol from p-nitrophenol upon the addition of NAD(P)H, although at a very low rate. A constitutive catechol 1, 2-dioxygenase activity yielding cis,cis-muconate was also detected in crude extracts of R. capsulatus. Further degradation of 4-nitrocatechol included both nitrite- and CO2-releasing steps since: (1) a strain of R. capsulatus (B10) unable to assimilate nitrate and nitrite released nitrite into the medium when grown with p-nitrophenol or 4-nitrocatechol, and the nitrite concentration was stoichiometric with the 4-nitrocatechol degraded, and (2) cultures of R. capsulatus growing microaerobically produced low amounts of 14CO2 from radiolabeled p-nitrophenol. The radioactivity was also incorporated into cellular compounds from cells grown with uniformly labeled 14C-p-nitrophenol. From these results we concluded that the xenobiotic is used as a carbon source by R. capsulatus, but that only the strain able to assimilate nitrite (E1F1) can use p-nitrophenol as a nitrogen source.

  13. Isolation of a significant fraction of non-phototroph diversity from a desert Biological Soil Crust

    Directory of Open Access Journals (Sweden)

    Ulisses eNunes da Rocha


    Full Text Available Biological Soil Crusts (BSCs are organosedimentary assemblages comprised of microbes and minerals in topsoil of terrestrial environments. BSCs strongly impact soil quality in dryland ecosystems (e.g., soil structure and nutrient yields due to pioneer species such as Microcoleus vaginatus; phototrophs that produce filaments that bind the soil together, and support an array of heterotrophic microorganisms. These microorganisms in turn contribute to soil stability and biogeochemistry of BSCs. Non-cyanobacterial populations of BSCs are less well known than cyanobacterial populations. Therefore, we attempted to isolate a broad range of numerically significant and phylogenetically representative BSC aerobic heterotrophs. Combining simple pre-treatments (hydration of BSCs under dark and light and isolation strategies (media with varying nutrient availability and protection from oxidative stress we recovered 402 bacterial and one fungal isolate in axenic culture, which comprised 116 phylotypes (at 97% 16S rRNA gene sequence homology, 115 bacterial and one fungal. Each medium enriched a mostly distinct subset of phylotypes, and cultivated phylotypes varied due to the BSC pre-treatment. The fraction of the total phylotype diversity isolated, weighted by relative abundance in the community, was determined by the overlap between isolate sequences and OTUs reconstructed from metagenome or metatranscriptome reads. Together, more than 8% of relative abundance of OTUs in the metagenome was represented by our isolates, a cultivation efficiency much larger than typically expected from most soils. We conclude that simple cultivation procedures combined with specific pre-treatment of samples afford a significant reduction in the culturability gap, enabling physiological and metabolic assays that rely on ecologically relevant axenic cultures.

  14. Melatonin in plants and other phototrophs: advances and gaps concerning the diversity of functions. (United States)

    Hardeland, Rüdiger


    Melatonin is synthesized in Alphaproteobacteria, Cyanobacteria, Dinoflagellata, Euglenoidea, Rhodophyta, Phae ophyta, and Viridiplantae. The biosynthetic pathways have been identified in dinoflagellates and plants. Other than in dinoflagellates and animals, tryptophan is not 5-hydroxylated in plants but is first decarboxylated. Serotonin is formed by 5-hydroxylation of tryptamine. Serotonin N-acetyltransferase is localized in plastids and lacks homology to the vertebrate aralkylamine N-acetyltransferase. Melatonin content varies considerably among species, from a few picograms to several micrograms per gram, a strong hint for different actions of this indoleamine. At elevated levels, the common and presumably ancient property as an antioxidant may prevail. Although melatonin exhibits nocturnal maxima in some phototrophs, it is not generally a mediator of the signal 'darkness'. In various plants, its formation is upregulated by visible and/or UV light. Increases are often induced by high or low temperature and several other stressors including drought, salinity, and chemical toxins. In Arabidopsis, melatonin induces cold- and stress-responsive genes. It has been shown to support cold resistance and to delay experimental leaf senescence. Transcriptome data from Arabidopsis indicate upregulation of genes related to ethylene, abscisic acid, jasmonic acid, and salicylic acid. Auxin-like actions have been reported concerning root growth and inhibition, and hypocotyl or coleoptile lengthening, but effects caused by melatonin and auxins can be dissected. Assumptions on roles in flower morphogenesis and fruit ripening are based mainly on concentration changes. Whether or not melatonin will find a place in the phytohormone network depends especially on the identification of molecular signals regulating its synthesis, high-affinity binding sites, and signal transduction pathways.

  15. Screening of compound bacteria for anaerobic fermentation with piggery biogas slurry and study the treatment effect of compound bacteria static test%猪场厌氧发酵沼液复合菌群的筛选及静态试验效果研究

    Institute of Scientific and Technical Information of China (English)

    林标声; 何玉琴; 黄燕翔; 邱丰艳


    The research aimed to directional select the compound bacteria from water samples which collected by the river and coastal pollution of pig farm biogas slurry discharge, and then enrichment them. These compound bacteria was used in treatment of piggery biogas slurry, it can effectively decompose harmful substances, suspended matte, but nitrogen, phosphorus and other nutrients can not decompose too much. The result indicated that 5%dosage of the compound bacteria treatment biogas slurry was best, on this condition, it can degrade the CODcr of biogas slurry, but did not use large amount of ammonia nitrogen and phosphorus. After treatment, the biogas slurry turbidity reduced and reaches the standards for irrigation water quality as it can effectively reduce ascaris egg, fecal coliform bacteria and other harmful substances and suspended matter of biogas slurry. Moreover, toxicity test results showed that after compound bacteria treatment, it can obviously reduce the initial biogas slurry toxicity as the germination rate and germination index of radish seed in biogas slurry were significantly improved. Therefore, after compound bacteria treatment, the piggery biogas slurry can use as fertilizer as it was nutrition, harmless, suspended matter less.%通过对猪场沼液排放的河流及沿岸收集污染的水样进行定向分离、富集培养,获得能有效分解沼液有害物质、悬浮物,但又不会过多利用氮、磷等营养成分的复合菌群。处理沼液的试验结果表明,选定添加0.5%复合菌群,其处理沼液CODcr效果最好,不会大量降解氨氮和磷,且能有效降低沼液中的蛔虫卵、粪大肠杆菌等有害物质,还能去除沼液中的悬浮物,降低沼液浊度,达到农田灌溉标准。毒性试验结果表明,经复合菌群处理后的沼液,其萝卜种子的发芽率和发芽指数均有显著提高,明显降低始沼液毒性。结果表明,猪场沼液经复合菌群处理后,营

  16. Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor (United States)

    Wang, Jin; Mahmood, Qaisar; Qiu, Jiang-Ping; Li, Yin-Sheng; Chang, Yoon-Seong; Li, Xu-Dong


    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

  17. Anaerobic biodegradation of linear alkylbenzene sulfonate (LAS) in upflow anaerobic sludge blanket (UASB) reactors. (United States)

    Sanz, José L; Culubret, Elayne; de Ferrer, Juan; Moreno, Alfonso; Berna, José L


    The anaerobic biodegradation of Linear Alkylbenzene Sulfonate (LAS) was studied in Upflow Anaerobic Sludge Blanket Reactors (UASB). One reactor was fed with easily degradable substrates and commercial LAS solution during a period of 3 months (Reactor 1), meanwhile a second reactor was fed with a commercial LAS solution without co-substrate (Reactor 2) during 4 months. Both reactors were operated with an organic loading rate of 4-5 mg-LAS/l x day and a hydraulic retention time of one day. The LAS biodegradation was determined by full mass balance. LAS was analysed by HPLC in the liquid phase (influent and effluent streams of the reactors) as well as in the solid phase (granular sludge used as biomass). The results indicate a high level of removal (primary biodegradation: 64-85%). Biodegradation was higher in the absence of external co-substrates than in the presence of additional sources of carbon. This indicates that the surfactant can be partially used as carbon and energy source by anaerobic bacteria. Under the operating conditions used, inhibition of the methanogenic activity or any other negative effects on the biomass due to the presence of LAS were not observed. The methanogenic activity remained high and stable throughout the experiment.

  18. Anaerobic Mercury Methylation and Demethylation by Geobacter bemidjiensis Bem. (United States)

    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


    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.

  19. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis (United States)

    Ali Shah, Fayyaz; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Ahmad Asad, Saeed


    Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed. PMID:24701142

  20. [Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge]. (United States)

    Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang


    Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

  1. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

    Directory of Open Access Journals (Sweden)

    Fayyaz Ali Shah


    Full Text Available Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.

  2. Anaerobic Digestion of Piggery Waste

    NARCIS (Netherlands)

    Velsen, van A.F.M.


    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes an

  3. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)


    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.

  4. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.


    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulate...

  5. Atomistic study of energy funneling in the light-harvesting complex of green sulfur bacteria

    CERN Document Server

    Huh, Joonsuk; Brookes, Jennifer C; Valleau, Stéphanie; Fujita, Takatoshi; Aspuru-Guzik, Alán


    Phototrophic organisms such as plants, photosynthetic bacteria and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have multiple functional and structural subunits, the energy is transferred in the form of molecular excitations with very high efficiency. Green sulfur bacteria are considered to be amongst the most efficient light-harvesting organisms. Despite multiple experimental and theoretical studies of these bacteria the physical origin of the efficient and robust energy transfer in their light-harvesting complexes is not well understood. To study excitation dynamics at the systems level we introduce an atomistic model that mimic a complete light-harvesting apparatus of green sulfur bacteria. The model contains about 4000 pigment molecules and comprises a double wall roll for the chlorosome, a baseplate and six Fenna-Matthews-Olson trimer complexes. We show that the fast relaxation within functional subunits combined with the...

  6. Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

    NARCIS (Netherlands)

    Janssen, A.J.H.; Lens, P.N.L.; Stams, A.J.M.; Plugge, C.M.; Sorokin, D.Y.; Muyzer, G.; Dijkman, H.; Zessen, van E.; Luimes, F.J.T.; Buisman, C.J.N.


    In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exempl

  7. Mimicking the oxygen minimum zones: stimulating interaction of aerobic archaeal and anaerobic bacterial ammonia oxidizers in a laboratory-scale model system

    NARCIS (Netherlands)

    Yan, J.; Haaijer, S.C.M.; Op den Camp, H.J.M.; van Niftrik, L.; Stahl, D.A.; Könneke, M.; Rush, D.; Sinninghe Damsté, J.S.; Hu, Y.Y.; Jetten, M.S.M.


    In marine oxygen minimum zones (OMZs), ammonia-oxidizing archaea (AOA) rather than marine ammonia-oxidizing bacteria (AOB) may provide nitrite to anaerobic ammonium-oxidizing (anammox) bacteria. Here we demonstrate the cooperation between marine anammox bacteria and nitrifiers in a laboratory-scale

  8. Anaerobic treatment performance and microbial population of thermophilic upflow anaerobic filter reactor treating awamori distillery wastewater. (United States)

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


    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.

  9. Phototrophic Biofilm Assembly in Microbial-Mat-Derived Unicyanobacterial Consortia: Model Systems for the Study of Autotroph-Heterotroph Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Jessica K.; Hutchison, Janine R.; Renslow, Ryan S.; Kim, Young-Mo; Chrisler, William B.; Engelmann, Heather E.; Dohnalkova, Alice; Hu, Dehong; Metz, Thomas O.; Fredrickson, Jim K.; Lindemann, Stephen R.


    Though microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, the diversity and complexity of natural systems and their intractability to in situ environmental manipulation makes elucidation of the principles governing these interactions challenging. Examination of primary succession during phototrophic biofilm assembly provides a robust means by which to elucidate the dynamics of such interactions and determine their influence upon recruitment and maintenance of phylogenetic and functional diversity in microbial communities. We isolated and characterized two unicyanobacterial consortia from the Hot Lake phototrophic mat, quantifying the structural and community composition of their assembling biofilms. The same heterotrophs were retained in both consortia and included members of Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes, taxa frequently reported as consorts of microbial photoautotrophs. Cyanobacteria led biofilm assembly, eventually giving way to a late heterotrophic bloom. The consortial biofilms exhibited similar patterns of assembly, with the relative abundances of members of Bacteroidetes and Alphaproteobacteria increasing and members of Gammaproteobacteria decreasing as colonization progressed. Despite similar trends in assembly at higher taxa, the consortia exhibited substantial differences in community structure at the species level. These similar patterns of assembly with divergent community structures suggest that, while similar niches are created by the metabolism of the cyanobacteria, the resultant webs of autotroph-heterotroph and heterotroph-heterotroph interactions driving metabolic exchange are specific to each primary producer. Altogether, our data support these Hot Lake unicyanobacterial consortia as generalizable model systems whose simplicity and tractability permit the deciphering of community assembly principles relevant to natural microbial communities.

  10. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB


    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  11. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    NARCIS (Netherlands)

    Weelink, S.A.B.


    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soi

  12. Degradation of BTEX by anaerobic bacteria: physiology and application

    NARCIS (Netherlands)

    Weelink, S.A.B.; Eekert, van M.H.A.; Stams, A.J.M.


    Pollution of the environment with aromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX) is often observed. The cleanup of these toxic compounds has gained much attention in the last decades. In situ bioremediation of aromatic hydrocarbons contaminated soils and gr

  13. Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria. (United States)


    Peptococcus micros 5.8 Fusobacterium varium 5.2 Clostridium sartagoformum 5.2 Clostridium tyrobutyricum 5.0 Bacteriological studies were also performed on...4.5 Non-sooreforming Gram- Corynebacterium sp. 4.4 positive rod 6.3 c-hemolytic streptococcus 4.0 Clostridium perfringens 6.1 Proteus mirabilis 4.0... Clostridium paraputrificum 6.0 Proteus morganii 3.9 Clostridium species 6.0 Moraxella sp. 3.1 Bacteroides fragilis 5.8 Peptococcus morbillorum 5.7

  14. Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

    DEFF Research Database (Denmark)

    Georgieva, Tania I.


    xylose conversion, effective glucose/xylose co-fermentation, and ethanol productivity of 1 g/l/h required for an economically viable bioethanol process. Furthermore, the fermentation of two undetoxified feed streams of industrial interest (acid hydrolyzed corn stover and wet-exploded wheat straw...... steps, various inhibitors towards microbial fermentation are generated along with the monomeric sugars. The inhibitors can be removed by various detoxification methods but the inclusion of this extra process step increases significantly the ethanol production cost. Compared with glucose, which can....... In order to keep ethanol production cost at a minimum, the major sugars in lignocellulosic biomass (glucose and xylose) must be converted into ethanol due to high raw material cost, typically about 40% of the total ethanol production cost. The need for a microorganism able to utilize both glucose...

  15. Isolation and Cultivation of Anaerobes

    DEFF Research Database (Denmark)

    Aragao Börner, Rosa


    Anaerobic microorganisms play important roles in different biotechnological processes. Their complex metabolism and special cultivation requirements have led to less isolated representatives in comparison to their aerobic counterparts.In view of that, the isolation and cultivation of anaerobic...... microorganisms is still a promising venture, and conventional methodologies as well as considerations and modifications are presented here. An insight into new methodologies and devices as well as a discussion on future perspectives for the cultivation of anaerobes may open the prospects of the exploitation...


    NARCIS (Netherlands)



    The normal flora of the intestinal tract, mainly consisting of anaerobic bacteria, protects the host against colonization by pathogenic microorganisms. Antimicrobial treatment with ceftriaxone may influence the colonic microflora and as a consequence, the protective effect. Ten healthy volunteers re

  17. Sulfate inhibition effect on sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    Sulaiman Al Zuhair


    Full Text Available There is an increasing interest in the potential of bacterial sulfate reduction as an alternative method for sulfate removal from wastewater. Under anaerobic conditions, sulfate-reducing bacteria (SRB utilize sulfate to oxidize organic compounds and generate sulfide (S2-. SRB were successfully isolated from sludge samples obtained from a local petroleum refinery, and used for sulfate removal. The effects of initial sulfate concentration, temperature and pH on the rate of bacterial growth and anaerobic sulfate removal were investigated and the optimum conditions were identified. The experimental data were used to determine the parameters of two proposed kinetic model, which take into consideration substrate inhibition effect. Keywords: Sulfate Reducing Bacteria, Sulfate, Kinetic Model, Biotreatement, Inhibition Received: 31 August 2008 / Received in revised form: 18 September 2008, Accepted: 18 September 2008 Published online: 28 September 2008

  18. Biotransformation of nonylphenol ethoxylates during sewage treatment under anaerobic and aerobic conditions

    Institute of Scientific and Technical Information of China (English)


    Biotransformation of nonylphenol ethoxylates (NPEOs) during continuous anaerobic sewage treatment was compared with the aerobic treatment of sewage spiked with 23 μmol/L technical NPEOs over a period of 90 d. Immediate degradation of NPEOs was observed under both anaerobic and aerobic conditions, indicating that the enzymes and bacteria required for NPEO degradation existed abundantly in both aerobic and anaerobic sludge. Both treatments achieved high removal (>92%) of the spiked NPEO9 mixture.Liquid chromatography-mass spectrometry (LC-MS) analysis showed that short-chain NPEOs (NPEO1-NPEO3) accumulated in anaerobic (2.01-2.56 μmol/L) and aerobic (1.62-2.03 μmol/L) effluents, with nonylphenol (NP) (0.24-0.31 μmol/L) as another group of metabolites in the anaerobic effluent, and nonylphenoxy carboxylates (NPECs) (2.79-3.30 μmol/L) in the aerobic effluent. Significant accumulation of NP in the anaerobic sludge and NPEO1-3 in the sludge of two reactors was observed. These results indicated that it was difficult to control these harmful metabolites in the conventional treatment processes. Denaturing gradient gel electrophoresis profiles of sludge samples support the speculation that the NPEO degradation bacteria might be the dominant indigenous species.

  19. Community structure and denitrification ability of aerobic and anaerobic denitrifying bacteria from mangrove wetland%红树林湿地中好氧-厌氧反硝化菌脱氮特性及其种群结构分析

    Institute of Scientific and Technical Information of China (English)

    林娜; 郭楚玲; 郭延萍; 柯林; 党志; 谭凤仪


    Mangrove wetlands dominate the coastline of tropical and subtropical regions. With the expansion of human activity along riverine and coastal shorelines, mangroves are subject to anthropogenic inputs, which introduee additional nitrogen to mangrove ecosystems. In the present study, both traditional cultivation and molecular method ( clone library and RFLP) were used to investigate the community strueture and abilities of denitrifying microorganism from Mai Po mangrove sediment. Twenty aerobic and anaerobic denitrifying bacteria strains were obtained and most of them had the abilities to remove 98% NO3- -N in 2 days. The aerobic denitrifying bacterial strains belonged to the genera of Pseudomonas, Comamonas and Acinetobacter. The anaerobie denitrifying bacterial strains were Pseudomonas, Agrobacterium, Uncultured Betaproteobacteria bacterium. To investigate the diversity of denitrifying bacteria in the mangrove sediments, nosZ gene clone library were constructed. 26 out of 50 clones belonged to 11 unknown groups, while the others were the Pennisetum (26%) , the β-proteobacterium (10%) , the Entandrophragma ( 4 % ) , the Pseudomonas ( 4 % ) and the denitrifying bacterium (4%). This indicated that Mai Po mangrove had high degree of taxonomic diversity of denitrifiers.%随着沿岸水体氮素富营养化的加剧,生物脱氮作用越来越受重视,位于海陆交界的湿地红树林生态系统作为一个自然脱氮体系备受关注.本研究以典型亚热带湿地红树林(香港Mai Po)作为对象,结合传统的富集筛选和分子生物学方法--建立nosZ基因克隆文库和RFLP分析技术对红树林沉积物中反硝化细菌脱氮能力、种群结构和丰度进行研究.从Mai Po红树林沉积物中共筛选到12株好氧反硝化菌和8株厌氧反硝化菌,其中好氧反硝化菌包括Pseudomonas(4株)、Comamonas(2株)和Acinetobacter(2株)等7个菌属,厌

  20. A characterization of anaerobic colonization and associated mucosal adaptations in the undiseased ileal pouch.

    LENUS (Irish Health Repository)

    Smith, F M


    INTRODUCTION: The resolution of pouchitis with metronidazole points to an anaerobic aetiology. Pouchitis is mainly seen in patients with ulcerative colitis pouches (UCP). We have recently found that sulphate reducing bacteria (SRB), a species of strict anaerobe, colonize UCP exclusively. Herein, we aimed to correlate levels of different bacterial species (including SRB) with mucosal inflammation and morphology. METHODS: Following ethical approval, fresh faecal samples and mucosal biopsies were taken from 9 patients with UCP and 5 patients with familial adenomatous polyposis pouches (FAPP). For the purposes of comparison, faecal samples and mucosal biopsies were also taken from the stomas of 7 of the 9 patients with UC (UCS). Colonization by four types of strict anaerobes (SRB, Clostridium perfringens, Bifidobacteria and Bacteroides) as well as by three types of facultative anaerobes (Enterococci, Coliforms and Lactobacilli) was evaluated. Inflammatory scores and mucosal morphology were assessed histologically in a blinded fashion by a pathologist. RESULTS: In general, strict anaerobes predominated over facultative in the UCP (P = 0.041). SRB were present in UCP exclusively. Even after exclusion of SRB from total bacterial counts, strict anaerobes still predominated. In the UCS, facultative anaerobes predominated. Strict and facultative anaerobes were present at similar levels in the FAPP. Enterococci were present at significantly reduced levels in the UCP when compared with the UCS (P = 0.031). When levels of SRB and other anaerobic species were individually correlated with mucosal inflammation and morphology, no trends were observed. CONCLUSION: We have previously identified that SRB exclusively colonize UCP. In addition we have now identified a novel increase in the strict\\/facultative anaerobic ratio within the UCP compared to UCS. These stark differences in bacterial colonization, however, appear to have limited impact on mucosal inflammation or morphology.

  1. Involvement of protozoa in anaerobic wastewater treatment process. (United States)

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


    It is only very rarely recognised in literature that anaerobic reactors may contain protozoa in addition to various bacterial and archeal groups. The role of protozoa in anaerobic degradation was studied in anaerobic continuous stirred tank reactors (CSTR) and batch tests. Anaerobic protozoa, especially the ciliated protozoa, have direct influence on the performance of CSTR at all organic loading rates (1-2g CODl(-1)d(-1)) and retention times (5-10 days). The studies revealed that chemical oxygen demand (COD) removal is strongly correlated to ciliate density in CSTR fed with oleate (suspended COD) and acetate (soluble COD). There was no significant difference in COD removal between reactors fed suspended COD and those fed soluble COD. However, the diversity and number of ciliates is greater in CSTR fed with particulate feed. The mixed liquor suspended solids (MLSS) representing biomass was significantly lower (16-34%) in CSTR with protozoa. In batch tests, increased COD removal and methane production was observed in sludge having ciliates as compared with sludge without protozoa. Methane production increased linearly with number of ciliates (R(2)=0.96) in batch tests with protozoa. Direct utilization of COD by flagellates and ciliates was observed in bacteria-suppressed cultures. The technological importance of these results is that reactors with protozoa-rich sludge can enhance the rate of mineralization of complex wastewater, especially wastewater containing particulate COD.

  2. Enhanced biogas yield from energy crops with rumen anaerobic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Prochazka, Jindrich; Zabranska, Jana; Dohanyos, Michal [Department of Water Technology and Environmental Engineering, Faculty of Environmental Technology, Institute of Chemical Technology in Prague, Prague (Czech Republic); Mrazek, Jakub; Strosova, Lenka; Fliegerova, Katerina [Laboratory of Anaerobic Microbiology, Institute of Animal Physiology and Genetics, CAS, v.v.i., Prague (Czech Republic)


    Anaerobic fungi (AF) are able to degrade crop substrates with higher efficiency than commonly used anaerobic bacteria. The aim of this study was to investigate ways of use of rumen AF to improve biogas production from energy crops under laboratory conditions. In this study, strains of AF isolated from feces or rumen fluid of cows and deer were tested for their ability to integrate into the anaerobic bacterial ecosystem used for biogas production, in order to improve degradation of substrate polysaccharides and consequently the biogas yield. Batch culture, fed batch culture, and semicontinuous experiments have been performed using anaerobic sludge from pig slurry fermentation and different kinds of substrates (celluloses, maize, and grass silage) inoculated by different genera of AF. All experiments showed a positive effect of AF on the biogas yield and quality. AF improved the biogas production by 4-22%, depending on the substrate and AF species used. However, all the cultivation experiments indicated that rumen fungi do not show long-term survival in fermenters with digestate from pig slurry. The best results were achieved during fed batch experiment with fungal culture Anaeromyces (KF8), in which biogas production was enhanced during the whole experimental period of 140 days. This result has not been achieved in semicontinuous experiment, where increment in biogas production in fungal enriched reactor was only 4% after 42 days. (copyright 2012 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Anaerobic Biodegradation of Detergent Surfactants


    Erich Jelen; Ute Merrettig-Bruns


    Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have str...

  4. Upflow anaerobic sludge blanket reactor--a review. (United States)

    Bal, A S; Dhagat, N N


    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

  5. Effect of copper and lead on two consortia of phototrophic microorganisms and their capacity to sequester metals

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, A. [Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Edifici C, Campus de UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona (Spain); Departamento de Recursos Hidrobiológicos, Universidad de Nariño, Pasto (N) (Colombia); Maldonado, J. [Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Edifici C, Campus de UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona (Spain); De los Rios, A. [Museo Nacional de Ciencias Naturales(CSIC), Serrano 115 dpdo, 28006 Madrid (Spain); Solé, A. [Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Edifici C, Campus de UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona (Spain); Esteve, I., E-mail: [Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Edifici C, Campus de UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona (Spain); Departamento de Recursos Hidrobiológicos, Universidad de Nariño, Pasto (N) (Colombia); Museo Nacional de Ciencias Naturales(CSIC), Serrano 115 dpdo, 28006 Madrid (Spain)


    Highlights: •We studied the tolerance-resistance of phototrophic microorganisms to copper and lead. •We determined the capacity of consortia of microorganisms to sequester copper and lead. •CLSM-λscan is a technique for evaluating in vivo effect of metals on microorganisms. •SEM-EDX and TEM-EDX determined the capacity of microorganisms to sequester metals. -- Abstract: The roles of consortia of phototrophic microorganisms have been investigated in this paper to determine their potential role to tolerate or resist metals and to capture them from polluted cultures. With this purpose, two consortia of microorganisms: on one hand, Geitlerinema sp. DE2011 (Ge) and Scenedesmus sp. DE2009 (Sc) (both identified in this paper by molecular biology methods) isolated from Ebro Delta microbial mats, and on the other, Spirulina sp. PCC 6313 (Sp) and Chroococcus sp. PCC 9106 (Ch), from Pasteur culture collection were polluted with copper and lead. In order to analyze the ability of these consortia to tolerate and capture metals, copper and lead were selected, because both have been detected in Ebro Delta microbial mats. The tolerance-resistance to copper and lead for both consortia was determined in vivo and at cellular level by Confocal Laser Scanning Microscopy (CLSM-λscan function). The results obtained demonstrate that both consortia are highly tolerant-resistant to lead and that the limits between the copper concentration having cytotoxic effect and that having an essential effect are very close in these microorganisms. The capacity of both consortia to capture extra- and intracellular copper and lead was determined by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) respectively, coupled to an Energy Dispersive X-ray detector (EDX). The results showed that all the microorganisms assayed were able to capture copper extracellularly in the extrapolymeric substances, and lead extra- and intracellularly in polyphosphate inclusions. Moreover

  6. Anaerobic oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean

    DEFF Research Database (Denmark)

    Treude, T.; Boetius, A.; Knittel, K.;


    At Hydrate Ridge (HR), Cascadia convergent margin, surface sediments contain massive gas hydrates formed from methane that ascends together with fluids along faults from deeper reservoirs. Anaerobic oxidation of methane (AOM), mediated by a microbial consortium of archaea and sulfate-reducing...... bacteria, generates high concentrations of hydrogen sulfide in the surface sediments. The production of sulfide supports chemosynthetic communities that gain energy from sulfide oxidation. Depending on fluid flow, the surface communities are dominated either by the filamentous sulfur bacteria Beggiatoa...

  7. Metagenomic and proteomic analyses to elucidate the mechanism of anaerobic benzene degradation

    Energy Technology Data Exchange (ETDEWEB)

    Abu Laban, Nidal [Helmholtz (Germany)


    This paper presents the mechanism of anaerobic benzene degradation using metagenomic and proteomic analyses. The objective of the study is to find out the microbes and biochemistry involved in benzene degradation. Hypotheses are proposed for the initial activation mechanism of benzene under anaerobic conditions. Two methods for degradation, molecular characterization and identification of benzene-degrading enzymes, are described. The physiological and molecular characteristics of iron-reducing enrichment culture are given and the process is detailed. Metagenome analysis of iron-reducing culture is presented using a pie chart. From the metagenome analysis of benzene-degrading culture, putative mobile element genes were identified in the aromatic-degrading configurations. Metaproteomic analysis of iron-reducing cultures and the anaerobic benzene degradation pathway are also elucidated. From the study, it can be concluded that gram-positive bacteria are involved in benzene degradation under iron-reducing conditions and that the catalysis mechanism of putative anaerobic benzene carboxylase needs further investigation.

  8. Effects of Oxytetracycline on Methane Production and the Microbial Communities During Anaerobic Digestion of Cow Manure

    Institute of Scientific and Technical Information of China (English)

    KE Xin; WANG Chun-yong; LI Run-dong; ZHANG Yun


    The effects of different concentrations of oxytetracycline (OTC) on the dynamics of bacterial and archaeal communities during the mesophilic anaerobic digestion (37°C) of cow manure were investigated. Before anaerobic digestion, OTC was added to digesters at concentrations of 20, 50, and 80 mg L-1, respectively. Compared with no-antibiotic control, all methane productions underwent different levels of inhibition at different concentrations of OTC. Changes in the bacterial and archaeal communities were discussed by using PCR-denaturing gradient gel electrophoresis (DGGE). Results showed that OTC affected the richness and diversity of bacterial and archaeal communities. The bacterial genus Flavobacterium and an uncultured bacterium (JN256083.1) were detected throughout the entire process of anaerobic digestion and seemed to be the functional bacteria. Methanobrevibacter boviskoreani and an uncultured archaeon (FJ230982.1) dominated the archaeal communities during anaerobic digestion. These microorganisms may have high resistance to OTC and may play vital roles in methane production.

  9. Anaerobic biofilm reactors for dark fermentative hydrogen production from wastewater: A review. (United States)

    Barca, Cristian; Soric, Audrey; Ranava, David; Giudici-Orticoni, Marie-Thérèse; Ferrasse, Jean-Henry


    Dark fermentation is a bioprocess driven by anaerobic bacteria that can produce hydrogen (H2) from organic waste and wastewater. This review analyses a relevant number of recent studies that have investigated dark fermentative H2 production from wastewater using two different types of anaerobic biofilm reactors: anaerobic packed bed reactor (APBR) and anaerobic fluidized bed reactor (AFBR). The effect of various parameters, including temperature, pH, carrier material, inoculum pretreatment, hydraulic retention time, substrate type and concentration, on reactor performances was investigated by a critical discussion of the results published in the literature. Also, this review presents an in-depth study on the influence of the main operating parameters on the metabolic pathways. The aim of this review is to provide to researchers and practitioners in the field of H2 production key elements for the best operation of the reactors. Finally, some perspectives and technical challenges to improve H2 production were proposed.

  10. Anaerobic degradation of landfill leachate using an upflow anaerobic fixed-bed reactor with microbial sulfate reduction. (United States)

    Thabet, Olfa Ben Dhia; Bouallagui, Hassib; Cayol, Jean-luc; Ollivier, Bernard; Fardeau, Marie-Laure; Hamdi, Moktar


    This study evaluated the anaerobic degradation of landfill leachate and sulfate reduction as a function of COD/(SO(4)(2-)) ratio in an upflow anaerobic fixed-bed reactor. The reactor, which was inoculated with a mixed consortium, was operated under a constant hydraulic retention time (HRT) of 5 days. We investigated the effect of COD/(SO(4)(2-)) ratio variation on the sulfate reduction efficiency, hydrogen sulfide production, chemical oxygen demand (COD) removal, conductivity, and pH variation. The best reactor performance, with significant sulfate reduction efficiency and COD removal efficiency of 91% and 87%, respectively, was reached under a COD/(SO(4)(2-)) ratio of 1.17. Under these conditions, microscopic analysis showed the abundance of vibrios and rod-shaped bacterial cells. Two anaerobic bacteria were isolated from the reactor sludge. Phylogenetic studies performed on these strains identified strain A1 as affiliated to Clostridium genus and strain H1 as a new species of sulfate-reducing bacteria affiliated to the Desulfovibrio genus. The closest phylogenetic relative of strain H1 was Desulfovibrio desulfuricans, at 96% similarity for partial 16S RNA gene sequence data. Physiological and metabolic characterization was performed for this strain.

  11. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes (United States)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.


    's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  12. Integrated Anaerobic-Aerobic Biodegradation of Multiple Contaminants Including Chlorinated Ethylenes, Benzene, Toluene, and Dichloromethane. (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki


    Complete bioremediation of soils containing multiple volatile organic compounds (VOCs) remains a challenge. To explore the possibility of complete bioremediation through integrated anaerobic-aerobic biodegradation, laboratory feasibility tests followed by alternate anaerobic-aerobic and aerobic-anaerobic biodegradation tests were performed. Chlorinated ethylenes, including tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC), and dichloromethane (DCM) were used for anaerobic biodegradation, whereas benzene, toluene, and DCM were used for aerobic biodegradation tests. Microbial communities involved in the biodegradation tests were analyzed to characterize the major bacteria that may contribute to biodegradation. The results demonstrated that integrated anaerobic-aerobic biodegradation was capable of completely degrading the seven VOCs with initial concentration of each VOC less than 30 mg/L. Benzene and toluene were degraded within 8 days, and DCM was degraded within 20 to 27 days under aerobic conditions when initial oxygen concentrations in the headspaces of test bottles were set to 5.3% and 21.0%. Dehalococcoides sp., generally considered sensitive to oxygen, survived aerobic conditions for 28 days and was activated during the subsequent anaerobic biodegradation. However, degradation of cis-DCE was suppressed after oxygen exposure for more than 201 days, suggesting the loss of viability of Dehalococcoides sp., as they are the only known anaerobic bacteria that can completely biodegrade chlorinated ethylenes to ethylene. Anaerobic degradation of DCM following previous aerobic degradation was complete, and yet-unknown microbes may be involved in the process. The findings may provide a scientific and practical basis for the complete bioremediation of multiple contaminants in situ and a subject for further exploration.

  13. Present and past contribution of anaerobic ammonium oxidation to nitrogen cycling as revealed by ladderane lipids

    NARCIS (Netherlands)

    Jaeschke, A.


    Anammox, the anaerobic oxidation of ammonium to dinitrogen gas with nitrite as the electron acceptor, constitutes a novel route to convert biologically available (fixed) nitrogen to gaseous N2. This process is mediated by specific bacteria belonging to the Planctomycetes that were initially discover

  14. Present and past contribution of anaerobic ammonium oxidation to nitrogen cycling as revealed by ladderane lipids

    NARCIS (Netherlands)

    Jaeschke, Andrea


    Abstract Anammox, the anaerobic oxidation of ammonium to dinitrogen gas with nitrite as the electron acceptor, constitutes a novel route to convert biologically available (fixed) nitrogen to gaseous N2. This process is mediated by specific bacteria belonging to the Planctomycetes that were initially

  15. Sulfide removal by moderate oxygenation of anaerobic sludge environments

    Energy Technology Data Exchange (ETDEWEB)

    Van der Zee, F.P.; Villaverde, S.; Polanco, F. [Valladolid Univ., Valladolid (Spain). Dept. of Chemical Engineering; Garcia, P.A.


    Treating wastewater through anaerobic bioreactors results in the formation of hydrogen sulfide. The sulfide can be removed from the biogas by introducing air directly into the anaerobic bioreactor system. This study presents the results of batch experiments that provided a better insight into the fate of sulfur compounds and oxygen during microaerobic sulfide oxidation in granular sludge. It was shown that sulfide could be removed rapidly upon introduction of low amounts of oxygen to the sulfide-amended batch vials with granular sludge treating vinasse. Initially, the sulfide was oxidized to elemental sulfur, thiosulfate and polysulfide. Significant production of sulfate did not occur. The introduction of oxygen, however, could result in the growth of aerobic organic-chemical oxygen demand-oxidizing bacteria that compete with sulfide oxidation for oxygen. 6 refs., 1 tab., 1 fig.

  16. Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

    Energy Technology Data Exchange (ETDEWEB)

    Babauta, Jerome T. [Washington State Univ., Pullman, WA (United States); Atci, Erhan [Washington State Univ., Pullman, WA (United States); Ha, Phuc T. [Washington State Univ., Pullman, WA (United States); Lindemann, Stephen R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ewing, Timothy [Washington State Univ., Pullman, WA (United States); Call, Douglas R. [Washington State Univ., Pullman, WA (United States); Fredrickson, James K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Beyenal, Haluk [Washington State Univ., Pullman, WA (United States)


    Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode- associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.

  17. Phototrophic biofilm assembly in microbial-mat-derived unicyanobacterial consortia: model systems for the study of autotroph-heterotroph interactions

    Directory of Open Access Journals (Sweden)

    Jessica K Cole


    Full Text Available Microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, but the diversity and complexity of natural systems and their intractability to in situ manipulation make it challenging to elucidate the principles governing these interactions. The study of assembling phototrophic biofilm communities provides a robust means to identify such interactions and evaluate their contributions to the recruitment and maintenance of phylogenetic and functional diversity over time. To examine primary succession in phototrophic communities, we isolated two unicyanobacterial consortia from the microbial mat in Hot Lake, Washington, characterizing the membership and metabolic function of each consortium. We then analyzed the spatial structures and quantified the community compositions of their assembling biofilms. The consortia retained the same suite of heterotrophic species, identified as abundant members of the mat and assigned to Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes. Autotroph growth rates dominated early in assembly, yielding to increasing heterotroph growth rates late in succession. The two consortia exhibited similar assembly patterns, with increasing relative abundances of members from Bacteroidetes and Alphaproteobacteria concurrent with decreasing relative abundances of those from Gammaproteobacteria. Despite these similarities at higher taxonomic levels, the relative abundances of individual heterotrophic species were substantially different in the developing consortial biofilms. This suggests that, although similar niches are created by the cyanobacterial metabolisms, the resulting webs of autotroph-heterotroph and heterotroph-heterotroph interactions are specific to each primary producer. The relative simplicity and tractability of the Hot Lake unicyanobacterial consortia make them useful model systems for deciphering interspecies interactions and assembly principles relevant to natural

  18. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter. (United States)

    Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M


    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.

  19. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    Energy Technology Data Exchange (ETDEWEB)

    Gannoun, H.; Bouallagui, H.; Okbi, A. [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia); Sayadi, S. [Laboratory of bioprocesses, Centre of Biotechnology of Sfax, Sfax (Tunisia); Hamdi, M., E-mail: [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia)


    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 deg. C) and thermophilic (55 deg. 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 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d 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/L d. 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.

  20. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.


    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.

  1. Evidence for horizontal gene transfer of anaerobic carbon monoxide dehydrogenases

    Directory of Open Access Journals (Sweden)

    Stephen eTechtmann


    Full Text Available Carbon monoxide (CO is commonly known as a toxic gas, yet it is used by both aerobic and anaerobic bacteria and many archaea. In this study, we determined the prevalence of anaerobic carbon monoxide dehydrogenases (anaerobic CODHs, or [Ni,Fe]-CODHs in currently available genomic sequence databases. More than 6% (185 genomes out of 2887 bacterial and archaeal genome sequences in the IMG database possess at least one gene encoding [Ni,Fe]-CODH, the key enzyme for anaerobic CO utilization. The phylogenetic study of this extended protein family revealed nine distinct clades of [Ni,Fe]-CODHs. These clades consisted of [Ni,Fe]-CODHs that, while apparently monophyletic within the clades, were encoded by microorganisms of disparate phylogeny, based on 16S rRNA sequences, and widely ranging physiology. Following this discovery, it was therefore of interest to examine the extent and possible routes of horizontal gene transfer (HGT affecting [Ni,Fe]-CODH genes and gene clusters that include [Ni,Fe]-CODHs.The genome sequence of the extreme thermophile Thermosinus carboxydivorans was used as a case study for HGT. The [Ni,Fe]-CODH operon of T. carboxydivorans differs from its whole genome in its G+C content by 8.2 mol%. Here, we apply statistical methods to establish acquisition by T. carboxydivorans of the gene cluster including [Ni,Fe]-CODH via HGT. Analysis of tetranucleotide frequency and codon usage with application of the Kullback-Leibler divergence metric showed that the [Ni,Fe]-CODH-1 operon of T. carboxidyvorans is quite dissimilar to the whole genome. Using the same metrics, the T. carboxydivorans [Ni,Fe]-CODH-1 operon is highly similar to the genome of the phylogenetically distant anaerobic carboxydotroph Carboxydothermus hydrogenoformans. These results allow to assume recent HTG of the gene cluster from a relative of C. hydrogenoformans to T. carboxydivorans or a more ancient transfer from a C. hydrogenoformans ancestor to a T. carboxydivorans

  2. Microbial degradation of 4-monobrominated diphenyl ether with anaerobic sludge

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Yang-hsin, E-mail: [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China); Chou, Hsi-Ling [Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 407, Taiwan, ROC (China); Peng, Yu-Huei [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China)


    Highlights: Black-Right-Pointing-Pointer BDE-3 was degraded with two anaerobes in different rates. Black-Right-Pointing-Pointer Glucose addition augment the debromination efficiencies. Black-Right-Pointing-Pointer Hydrogen gas was detected and relative microbes were identified. Black-Right-Pointing-Pointer Extra-carbon source enhanced degradation partial due to H{sub 2}-generation bacteria. - Abstract: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant additives for many plastic and electronic products. Owing to their ubiquitous distribution in the environment, multiple toxicity to humans, and increasing accumulation in the environment, the fate of PBDEs is of serious concern for public safety. In this study, the degradation of 4-monobrominated diphenyl ether (BDE-3) in anaerobic sludge and the effect of carbon source addition were investigated. BDE-3 can be degraded by two different anaerobic sludge samples. The by-products, diphenyl ether (DE) and bromide ions, were monitored, indicating the reaction of debromination within these anaerobic samples. Co-metabolism with glucose facilitated BDE-3 biodegradation in terms of kinetics and efficiency in the Jhongsing sludge. Through the pattern of amplified 16S rRNA gene fragments in denatured gradient gel electrophoresis (DGGE), the composition of the microbial community was analyzed. Most of the predominant microbes were novel species. The fragments enriched in BDE-3-degrading anaerobic sludge samples are presumably Clostridium sp. This enrichment coincides with the H{sub 2} gas generation and the facilitation of debromination during the degradation process. Findings of this study provide better understanding of the biodegradation of brominated DEs and can facilitate the prediction of the fate of PBDEs in the environment.

  3. Microbial decolorization of reactive black-5 in a two-stage anaerobic-aerobic reactor using acclimatized activated textile sludge. (United States)

    Mohanty, Sagarika; Dafale, Nishant; Rao, Nageswara Neti


    A two-stage anaerobic-aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent was used to degrade reactive black 5 dye (RB-5). The anaerobic step was studied in more detail by varying the dye concentration from 100 to 3000 mg l(-1). The results showed that major decolorization was achieved during the anaerobic process. The time required for decolorization by > 90% increased as the concentration of the dye increased. It was also found that maintaining dissolved oxygen (DO) concentration below 0.5 mg l(-1 )and addition of a co-substrate viz., glucose, facilitates anaerobic decolorization reaction remarkably. An attempt was made to identify the metabolites formed in anaerobic process by using high performance liquid chromatography (HPLC) and UV-VIS spectrophotometry. A plate assay was performed for the detection of dominant decolorizing bacteria. Only a few bacterial colonies with high clearing zones (decolorization zones) were found. The results showed that under anaerobic condition RB-5 molecules were reduced and aromatic amines were generated. The aromatic amine metabolite was partly removed in subsequent aerobic bio-treatment. It was possible to achieve more than 90% decolorization and approximately 46% reduction in amine metabolite concentration through two-stage anaerobic-aerobic treatment after a reaction period of 2 days.

  4. Effects of microbial inhibitors on anaerobic degradation of DDT

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.S.; Chiu, T.C.; Yen, J.H. [National Taiwan Univ., Taipei (Taiwan)


    Chlorinated insecticide DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] was extensively used for controlling pests in the agricultural field and human-being living environments in the past several decades. Due to the chemical stability, DDT was extremely persistent and recalcitrant in soils and sediments and it was banned by nations. Microorganisms usually play important roles in reducing organochlorine compounds in the environments. Under low-oxygen conditions, microbial dechlorination is thought as the onset of highly chlorinated compounds. Methanogenic and sulfate-reducing bacteria participate in microbial dechlorination under anaerobic condition has been reported. In this study, a mixed anaerobic culture enabling to dechlorinate DDT was obtained from river sediment in Taiwan. In order to understand the effect of these microorganisms on DDT dechlorination, microbial inhibitors BESA (2-bromoethanesulfonate) and molybdate, for inhibiting methanogenic and sulfate-reducing bacteria, respectively, were chosen to investigate the interaction between specific microbial communities and their degradation activities. Besides, a molecular technique, denaturing gradient gel electrophoresis (DGGE), based on analyzing the 16S rDNA of bacteria, was used for monitoring the bacterial community structure in this study.

  5. Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin

    NARCIS (Netherlands)

    Russ, L.; Kartal, B.; Op den Camp, H.J.M.; Sollai, M.; Le Bruchec, J.; Caprais, J.-C.; Godfroy, A.; Sinninghe Damsté, J.S.; Jetten, M.S.M.


    Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox) bacteria

  6. A microdiversity study of anammox bacteria reveals a novel Candidatus Scalindua phylotype in marine oxygen minimum zones

    Digital Repository Service at National Institute of Oceanography (India)

    Woebken, D.; Lam, P.; Kuypers, M.M.M.; Naqvi, S.W.A; Kartal, B.; Strous, M.; Jetten, M.S.M.; Fuchs, B.M.; Amann, R.

    The anaerobic oxidation of ammonium (anammox) contributes significantly to the global loss of fixed nitrogen and is carried out by a deep branching monophyletic group of bacteria within the phylum Planctomycetes. Various studies have implicated...

  7. Anaerobic co-culture of mesenchymal stem cells and anaerobic pathogens - a new in vitro model system.

    Directory of Open Access Journals (Sweden)

    Katja Kriebel

    Full Text Available BACKGROUND: Human mesenchymal stem cells (hMSCs are multipotent by nature and are originally isolated from bone marrow. In light of a future application of hMSCs in the oral cavity, a body compartment with varying oxygen partial pressures and an omnipresence of different bacterial species i.e. periodontitis pathogens, we performed this study to gain information about the behavior of hMSC in an anaerobic system and the response in interaction with oral bacterial pathogens. METHODOLOGY/PRINCIPAL FINDINGS: We established a model system with oral pathogenic bacterial species and eukaryotic cells cultured in anaerobic conditions. The facultative anaerobe bacteria Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were studied. Their effects on hMSCs and primary as well as permanent gingival epithelial cells (Ca9-22, HGPEC were comparatively analyzed. We show that hMSCs cope with anoxic conditions, since 40% vital cells remain after 72 h of anaerobic culture. The Ca9-22 and HGPEC cells are significantly more sensitive to lack of oxygen. All bacterial species reveal a comparatively low adherence to and internalization into hMSCs (0.2% and 0.01% of the initial inoculum, respectively. In comparison, the Ca9-22 and HGPEC cells present better targets for bacterial adherence and internalization. The production of the pro-inflammatory chemokine IL-8 is higher in both gingival epithelial cell lines compared to hMSCs and Fusobacterium nucleatum induce a time-dependent cytokine secretion in both cell lines. Porphyromonas gingivalis is less effective in stimulating secretion of IL-8 in the co-cultivation experiments. CONCLUSIONS/SIGNIFICANCE: HMSCs are suitable for use in anoxic regions of the oral cavity. The interaction with local pathogenic bacteria does not result in massive pro-inflammatory cytokine responses. The test system established in this study allowed further investigation of parameters prior to set up of

  8. The ecology and biotechnology of sulphate-reducing bacteria

    NARCIS (Netherlands)

    Muyzer, G.; Stams, A.J.M.


    Sulphate-reducing bacteria (SRB) are anaerobic microorganisms that use sulphate as a terminal electron acceptor in, for example, the degradation of organic compounds. They are ubiquitous in anoxic habitats, where they have an important role in both the sulphur and carbon cycles. SRB can cause a seri

  9. Nitrifying and denitrifying bacteria in aerobic granules formed in sequencing batch airlift reactors

    Institute of Scientific and Technical Information of China (English)

    WANG Fang; YANG Fenglin; QI Aijiu


    The purpose of this study was to investigate nitrifying bacteria and denitrifying bacteria isolated from aerobic granules.Aerobic granules were formed in an internal-circulate sequencing batch airlift reactor(SBAR)and biodegradation of NH3 -N was analyzed in the reactor.Bacteria were isolated and determined from aerobic granules using selected media.The growth properties and morphology of bacteria colonies were observed by controlling aerobic or anaerobic conditions in the culture medium.It was found that bacteria in aerobic granules were diverse and some of them were facultative aerobes.The diversity of bacteria in aerobic granules was a premise of simultaneous nitrification and denitrification.

  10. Potential for anaerobic conversion of xenobiotics

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank;


    This review covers the latest research on the anaerobic biodegradation of aromatic xenobiotic compounds, with emphasis on surfactants, polycyclic aromatic hydrocarbons, phthalate esters, polychlorinated biphenyls, halogenated phenols, and pesticides. The versatility of anaerobic reactor systems...

  11. Truce with oxygen - A naerobiosis outcompete aerobiosis in the Antarctic lacustrine bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; DeSouza, M.J.B.D.; Chandramohan, D.

    The total number of bacteria counted directly by epifluorescent microscopy showed that they ranged from 10 sup(8)-10 sup(-1) in Antarctic lake water samples. The percentages of retrievable viable counts (RVC) of anaerobic bacteria (AnB) was greater...

  12. Occurrence and activity of anammox bacteria in surface sediments of the southern North Sea

    NARCIS (Netherlands)

    Bale, N.J.; Villanueva, L.; Fan, H.; Stal, L.J.; Hopmans, E.C.; Schouten, S.; Sinninghe Damsté, J.S.


    We investigated the occurrence and activity of anaerobic ammonia oxidation (anammox) bacteria in sandy and muddy sand sediments of the southern North Sea. The presence of anammox bacteria was established through the detection of specific phosphocholine-monoether ladderane lipids, 16S rRNA gene, and

  13. Energetics and kinetics of anaerobic aromatic and fatty acid degradation

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.


    The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, was studied in coculture with Desulfovibrio strain G11. The threshold value for benzoate degradation was dependent on the acetate concentration with benzoate threshold values ranging from 2.4 [mu]M at 20 mM acetate to 30.0 [mu]M at 65 mM acetate. Increasing acetate concentrations also inhibited the rate of benzoate degradation with a apparent K[sub i] for acetate inhibition of 7.0 mM. Lower threshold values were obtained when nitrate rather than sulfate was the terminal electron acceptor. These data are consistent with a thermodynamic explanation for the threshold, and suggest that there is a minimum Gibbs free energy value required for the degradation of benzoate. An acetoacetyl-CoA thiolase has been isolated from Syntrophomonas wolfei; it is apparently a key enzyme controlling the synthesis of poly-B-hydroxyalkanoate from acetyl-CoA in this organism. Kinetic characterization of the acetoacetyl-CoA thiolase from S. wolfei showed that it is similar in its structural, kinetic, and apparent regulatory properties to other biosynthetic acetoacetyl-CoA thiolases from phylogenetically distinct bacteria that synthesize PHA. Intracellular concentrations of CoA and acetyl-CoA are believed to be critical factors regulating the activity of the acetoacetyl-CoA thiolase in S. wolfei. We have also isolated and characterized several new halophilic anaerobic fermentative anaerobes. Phylogenetic analysis indicates that one of these bacteria is a new species in the genus, Haloanaerobium. Two other species appear to be members of the genus, Halobacteroides. Several halophilic acetoclastic methanogenic bacteria have also been isolated and their physiological properties are currently under investigation. We have also isolated an acetate-using dissimilatory iron-reducing bacterium.

  14. Bacteria Isolated from Post-Partum Infections

    Directory of Open Access Journals (Sweden)

    Nahid Arianpour


    Full Text Available Objective: This study was undertaken with an aim to determine bacterial species involved in post partum infections and also their abundance in patients admitted to at Khanevadeh hospital. In this study out of three different kinds of postpartum infections (i.e. genital, breast and urinary tract, only genital infection is considered.Materials and Methods: Post partum infection among 6077 patients (inpatients and re-admitted patients of Khanevadeh hospital from 2003 till 2008 was studied in this descriptive study. Samples were collected from patients for laboratory diagnosis to find out the causative organisms.Results: Follow up of mothers after delivery revealed 7.59% (461 patients had post partum infection, out of which 1.03% (63 patients were re-hospitalized. Infection was more often among younger mothers. Bacteria isolated and identified were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora of the site of infection. Though, some pathogenic bacteria like Staphylococcus aureus, Neisseria gonorrhea, Chlamydia trachomatis,were also the causative agents. The commonest infection was infection at the site of episiotomy. Conclusion: Puerperal infection was detected in of 7.59% mothers. Bacteria isolated were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora. However; some pathogenic bacteria were isolated.

  15. Anaerobic electrochemical membrane bioreactor and process for wastewater treatment

    KAUST Repository

    Amy, Gary


    An anaerobic electrochemical membrane bioreactor (AnEMBR) can include a vessel into which wastewater can be introduced, an anode electrode in the vessel suitable for supporting electrochemically active microorganisms (EAB, also can be referred to as anode reducing bacteria, exoelectrogens, or electricigens) that oxidize organic compounds in the wastewater, and a cathode membrane electrode in the vessel, which is configured to pass a treated liquid through the membrane while retaining the electrochemically active microorganisms and the hydrogenotrophic methanogens (for example, the key functional microbial communities, including EAB, methanogens and possible synergistic fermenters) in the vessel. The cathode membrane electrode can be suitable for catalyzing the hydrogen evolution reaction to generate hydro en.

  16. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær


    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was......, however, found to be crucial for determining the period needed before full capacity of the thermophilic plant could be achived. The importance of balanced loading, determined by the concentration of active biomass, is discussed. Finally, data will be shown on the optimal and maximal temperature...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  17. Pathways and Bioenergetics of Anaerobic Carbon Monoxide Fermentation. (United States)

    Diender, Martijn; Stams, Alfons J M; Sousa, Diana Z


    Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO-rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis, and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

  18. Pathways and bioenergetics of anaerobic carbon monoxide fermentation.

    Directory of Open Access Journals (Sweden)

    Martijn eDiender


    Full Text Available Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.

  19. Anaerobic treatment of lactic waste and goat manure

    Directory of Open Access Journals (Sweden)

    J. Luís Magaña-Ramírez


    Full Text Available Anaerobic digestion was carried out to obtain biogas from lactic waste in combination with goat manure. Waste from lactic products such as cream, cheese and whey was mixed with goat manure using three formulations; the quantity of waste from cream and cheese was maintained, and only the quantity of manure and whey was varied. Methanogenic bacteria obtained from predigestion of goat manure were used as inoculants. Temperature was 35ºC and pH 7.0.Biogas methane percentage was determined by gas chromatography. The results showed that the highest methane concentration obtained was 82% with formulation III.

  20. 21 CFR 866.2120 - Anaerobic chamber. (United States)


    ... 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. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic...

  1. The phenomenon of granulation of anaerobic sludge.

    NARCIS (Netherlands)

    Hulshoff Pol, L.W.


    Successful high-rate anaerobic wastewater treatment can only be accomplished when the slowgrowing anaerobic biomass is efficiently held back in the anaerobic treatment system. This biomass retention can be achieved in various ways including immobilization of the organisms on fixed materials and immo

  2. Microbial populations of an upflow anaerobic sludge blanket reactor treating wastewater from a gelatin industry. (United States)

    Vieira, A M; Bergamasco, R; Gimenes, M L; Nakamura, C V; Dias Filho, B P


    The microbial populations of an upflow anaerobic sludge blanket reactor, used for treating wastewater from the gelatin industry, were studied by microbiological methods and phase-contrast and electron microscopy. Microscopy examination of the sludge showed a complex mixture of various rod-shaped and coccoid bacterial pluslong filaments and verymobile curved rods. In addition free-living anaerobic ciliates and flagellates were also observed. The trophic group population observed in decreasing order of dominance were hydrolytic and acetogenic at 10(6) and sulfate reducing and methanogenic at 10(5). The rate of methane production in anaerobic granular sludge cultivated in growth medium supplement with formate pressurized with H2:CO2 showed a significant increase in methane yield compared with theseed culture containingthe same substrate and atmosphere of N2:CO2. Similar rates of methane production were observed when the growth medium was supplemented with acetate pressurized either with H2:CO2 or N2:CO2. The number of total anaerobic bacteria at 10(7), fecal coliforms and total coliforms at 10(6), and fecal streptococci at 10(3) is based on colony counts on solid media. The four prevalent species of facultative anaerobic gram-negative bacteria that belong to the family of Enterobacteriaceae were identified as Escherichia coli, Esherichia fergusonii, Klebsiella oxytoca, and Citrobacter freundii. The species Aeromonas hydrophila, Aeromonas veronii, Acinetobacter iwoffi and Stenotrophomonas maltophila were the most frequently isolated glucose fermenting and nonfermenting gram-negative bacilli.

  3. Single-cell analysis of growth and cell division of the anaerobe Desulfovibrio vulgaris Hildenborough

    Directory of Open Access Journals (Sweden)

    Anouchka eFievet


    Full Text Available 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.

  4. Perspectives of Anaerobic Soil Disinfestation

    NARCIS (Netherlands)

    Lamers, J.G.; Runia, W.T.; Molendijk, L.P.G.; Bleeker, P.O.


    Biological soil disinfestation is an environmentally friendly method to disinfest soil. From now on we refer to it as anaerobic soil disinfestation (ASD). With ASD a green manure crop (40 t/ha) is homogeneously incorporated into the topsoil (0-30 cm) after which the field is lightly compacted and ir

  5. Anaerobic granular sludge and biofilm reactors

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye


    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  6. Production of a ruminant protein supplement by anaerobic fermentation of feedlot waste filtrate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, C.A.; Erdman, M.D.


    In studies initiated to develop simple and efficient procedures for the production of feed supplements, it was shown that the filtrate from feedlot wastes diluted with water and filtered could be fermented under anaerobic conditions by mixed rumen bacteria, Lactobacilli, or natural microflora from the feedlot wastes to produce a protein-rich feed supplement. The filtrate is low in carbohydrate and therefore supplemental carbohydrate in the form of whey, molasses, starch from potato processing wastes, or corn starch is necessary. Rigid anaerobic conditions need not be maintained nor must aseptic conditions be observed. (JSR)

  7. Methanethiol Removal from Biogas by Biological Conversion in an Anaerobic Biotrickling Filter

    Institute of Scientific and Technical Information of China (English)

    王佳佳; 张卫江; 徐姣


    In this study, methanethiol(MT)-degradation bacteria were cultivated by using MT, methanol and trimethylamine as carbon sources under anaerobic conditions. It was found that the batch bacteria used MT and metha-nol as carbon sources grew faster than those used trimethylamine. The enriched bacteria used MT and methanol as the carbon sources were respectively inoculated in different biotrickling filters. The biological conversion performance of MT under anaerobic conditions was investigated in biotrickling filters. The results showed that the performance of the biotrickling filter inoculated with the bacteria enriched using MT was better than that inoculated with the bacteria en-riched using methanol. When the inlet concentration of MT was 0.005vol%(50,ppm), the empty bed residence time was 50 s, pH value was 8.0, and the flow rate of the nutrient solution was 10 L/h, the removal efficiency of MT reached 95.3%. Adding methanol stimulated the growth of the biomass and the degradation of MT, but caused that some bacteria only degrading methanol outcompeted the bacteria only degrading MT. The concentration of sodium bicarbonate in the nutrient solution needed to be controlled lower than 30 g/L, otherwise, it would be harmful to the degradation of MT.

  8. Combined stable isotope, proteomic, metabolomics, and spatial specific analysis to track carbon flow through a hypersaline phototrophic microbial mat (United States)

    Moran, J.; Cory, A.; Riha, K. M.; Huang, E. L.; Gritsenko, M. A.; Kim, Y. M.; Metz, T. O.; Lipton, M. S.


    Tracking labeled substrates through microbial mat systems can help elucidate carbon dynamics, species interactions, and niche partitioning, but the inherent microbial complexity of these systems makes them difficult to probe with single analytical techniques. Here we use a combination of different tools to track three labeled substrates through a benthic phototrophic mat from Hot Lake. Hot Lake is a hypersaline, meromictic lake located in an endorheic basin in north-central Washington which, despite extreme salinity and seasonal water temperatures (> 55 ˚C), hosts dense, phototrophic benthic microbial mats. Cyanobacteria are the dominant CO2-fixing organisms in the system and we seek to understand the spatial and metabolic controls on how the carbon initially fixed by mat cyanobacteria is transferred to associated heterotrophic populations spread throughout the mat strata. We performed ex situ incubations over a complete diel cycle with 13C labeled bicarbonate, acetate, and glucose. Traditional elemental analysis IRMS provided an estimate of bulk label uptake to total biomass and showed that both bicarbonate and acetate were incorporated only during daylight while glucose uptake was nearly constant through the cycle. Spatially resolved isotope analysis using laser ablation IRMS showed distinctive patterns between the different substrates with bicarbonate having highest uptake in the top third of the mat, acetate uptake focused near the mat's center, and glucose showing similar uptake at all mat depths. Proteomic analysis showed a longer lag in substrate conversion to protein than to biomass and a distinct spike in the number of labeled peptides in the bicarbonate incubation near the end of the diel cycle. Proteomic analysis confirmed that photosynthetic organisms showed the highest rates of label conversion to protein but heterotrophic organisms also incorporated label into their peptides. Metabolomic analysis demonstrated the high conversion of organic substrates

  9. Treatment of Chinese Traditional Medicine Wastewater by Photosynthetic Bacteria

    Institute of Scientific and Technical Information of China (English)

    WANG You-zhi; WANG Feng-jun; BAO Li


    The influence factors treating wastewater of Chinese traditional medicine extraction by photosynthetic bacteria are tested and discussed. The results indicate that the method of photosynthetic bacteria can eliminate COD and BCD from wastewater in high efficiency. And it also has high load shock resistance. On the conditions of slight aerobic and semi-darkness, treating wastewater of Chinese traditional medicine extraction, the method has better efficiency to eliminate COD and BOD from the wastewater than those by anaerobic illumination and aerobic darkness treatments. After pretreatment of hydrolytic acidization, the removal rate of COD in the wastewater reached more than 85 %, and that rate of BOD reached more than 90% in the treating system of photosynthetic bacteria. It may be more feasible and advantageous than traditional anaerobic biological process to treat organic wastewater using PSB system.

  10. NC10 bacteria in marine oxygen minimum zones

    DEFF Research Database (Denmark)

    Padilla, Cory C; Bristow, Laura A; Sarode, Neha


    Bacteria of the NC10 phylum link anaerobic methane oxidation to nitrite denitrification through a unique O2-producing intra-aerobic methanotrophy pathway. A niche for NC10 in the pelagic ocean has not been confirmed. We show that NC10 bacteria are present and transcriptionally active in oceanic....... rRNA and mRNA transcripts assignable to NC10 peaked within the OMZ and included genes of the putative nitrite-dependent intra-aerobic pathway, with high representation of transcripts containing the unique motif structure of the nitric oxide (NO) reductase of NC10 bacteria, hypothesized...

  11. Mechanism of uranium (VI) removal by two anaerobic bacterial communities

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Monica [Centro de Ciencias do Mar, Universidade do Algarve, FCT-DQF (edificio 8), Campus de Gambelas, 8005-139 Faro (Portugal); Faleiro, Maria Leonor [IBB - Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, FCT, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, Ana M. Rosa da [Centro de Investigacao em Quimica do Algarve, Universidade do Algarve, FCT, DQF, Campus de Gambelas, 8005-139 Faro (Portugal); Chaves, Sandra; Tenreiro, Rogerio [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biodiversidade, Genomica Integrativa e Funcional (BioFIG), Campus de FCUL, Campo Grande, 1749-016 Lisboa (Portugal); Matos, Antonio Pedro [Servico de Anatomia Patologica, Hospital Curry Cabral, Lisboa (Portugal); Costa, Maria Clara, E-mail: [Centro de Ciencias do Mar, Universidade do Algarve, FCT-DQF (edificio 8), Campus de Gambelas, 8005-139 Faro (Portugal)


    The mechanism of uranium (VI) removal by two anaerobic bacterial consortia, recovered from an uncontaminated site (consortium A) and other from an uranium mine (consortium U), was investigated. The highest efficiency of U (VI) removal by both consortia (97%) occurred at room temperature and at pH 7.2. Furthermore, it was found that U (VI) removal by consortium A occurred by enzymatic reduction and bioaccumulation, while the enzymatic process was the only mechanism involved in metal removal by consortium U. FTIR analysis suggested that after U (VI) reduction, U (IV) could be bound to carboxyl, phosphate and amide groups of bacterial cells. Phylogenetic analysis of 16S rRNA showed that community A was mainly composed by bacteria closely related to Sporotalea genus and Rhodocyclaceae family, while community U was mainly composed by bacteria related to Clostridium genus and Rhodocyclaceae family.

  12. Development of algae-bacteria granular consortia in photo-sequencing batch reactor. (United States)

    Liu, Lin; Fan, Hongyong; Liu, Yuhong; Liu, Chaoxiang; Huang, Xu


    The development and properties of algae-bacteria granular consortia, which cultivated with the algae (Chlorella and Scenedesmus) and aerobic granules, was investigated in this experiment. The results indicated that the granular consortia could be successfully developed by selection pressure control, and the algal biomass and extracellular polymeric substances (EPS) concentration in the consortia showed notable correlation with the operating parameters of reactor. The maximum specific removal rates of total nitrogen and phosphate were obtained from the granular consortia with the highest algal biomass, yet the correlation between the fatty acid methyl esters yield and the algal biomass in the consortia was not markedly observed. The seed algae maintained dominance in the phototroph community, whereas the cyanobacteria only occupied a small proportion (5.2-6.5%). Although the bacterial communities with different operational strategies showed significant difference, the dominated bacteria (Comamonadaceae, 18.79-36.25%) in the mature granular consortia were similar.

  13. Modelling of Two-Stage Anaerobic Treating Wastewater from a Molasses-Based Ethanol Distillery with the IWA Anaerobic Digestion Model No.1

    Directory of Open Access Journals (Sweden)

    Kittikhun Taruyanon


    Full Text Available This paper presents the application of ADM1 model to simulate the dynamic behaviour of a two-stage anaerobic treatment process treating the wastewater generated from the ethanol distillery process. The laboratory-scale process comprised an anaerobic continuous stirred tank reactor (CSTR and an upflow anaerobic sludge blanket (UASB connecting in series, was used to treat wastewater from the ethanol distillery process. The CSTR and UASB hydraulic retention times (HRT were 12 and 70 hours, respectively. The model was developed based on ADM1 basic structure and implemented with the simulation software AQUASIM. The simulated results were compared with measured data obtained from using the laboratory-scale two-stage anaerobic treatment process to treat wastewater. The sensitivity analysis identified maximum specific uptake rate (km and half-saturation constant (Ks of acetate degrader and sulfate reducing bacteria as the kinetic parameters which highly affected the process behaviour, which were further estimated. The study concluded that the model could predict the dynamic behaviour of a two-stage anaerobic treatment process treating the ethanol distillery process wastewater with varying strength of influents with reasonable accuracy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Xun, Luying


    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.

  15. Rhizosphere Bacteria

    Directory of Open Access Journals (Sweden)

    N.V. Feoktistova


    Full Text Available The review deals with the analysis of modern literature data on rhizosphere bacteria and their role in plant life. The structure of rhizosphere has been characterized. The role of plants as the centers of formation of microbial communities has been shown. Data on the main groups of microorganisms inhabiting the rhizosphere have been provided. The associative relationship between rhizobacteria and partner plants has been investigated. The modern concept of holobiont defined as the whole host plant organism and microorganisms associated with it has been reviewed. The role of rhizobacteria in the processes of nitrogen fixation has been discussed in detail. The mechanisms of direct stimulation of plant growth by biosynthesis of phytohormones, improvement of phosphorus and nitrogen nutrition, increase in resistance to stress, and stimulation mediated by antagonism against pathogenic microorganisms have been analyzed. The criteria for selection of rhizobacteria for practical purposes have been discussed.

  16. Anaerobic waste water purification and biogas production in a pulsed bioreactor. Anaerobe Abwasserreinigung mit Biogasgewinnung in einem gepulsten Bioreaktor

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, K.Y.


    The author's experiments were carried out in a novel type of bioreactor. In view of the advantages in the anaerobic process (high concentrations of biomass), the microorganisms were retained inside the bioreactor by fixation on a carrier. To avoid the problems otherwise encountered in bioreactors with fixed bacteria, in the pulsed bioreactor the block of foamed polymer carrying the bacteria is moved upwards and downwards in a single period at longer intervals of time. The reactor geometry and the pulsed movement assure a uniform and strong flow through the carrier material; gas bubbles are quickly removed from the bacterial surfaces and led out of the bioreactor, thus ensuring uniform bacterial supply and discharge. The biochemical conversion rate was determined using a highly burdened liquid filtrate waste. The conversion rate and gas productivity were found to be a function of the time of residue and room burden.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, H., Jr.; Rai, D.; Xun, L.


    The complexation of radionuclides (e.g., plutonium (Pu) and {sup 60}Co) by codisposed ethylenediaminetetraacetate (EDTA) has enhanced their transport in sediments at DOE sites. Our previous NABIR research investigated the aerobic biodegradation and biogeochemistry of Pu(IV)-EDTA. Plutonium(IV) forms stable complexes with EDTA under aerobic conditions and an aerobic EDTA degrading bacterium can degrade EDTA in the presence of Pu and decrease Pu mobility. However, our recent studies indicate that while Pu(IV)-EDTA is stable in simple aqueous systems, it is not stable in the presence of relatively soluble Fe(III) compounds (i.e., Fe(OH){sub 3}(s)--2-line ferrihydrite). Since most DOE sites have Fe(III) containing sediments, Pu(IV) in likely not the mobile form of Pu-EDTA in groundwater. The only other Pu-EDTA complex stable in groundwater relevant to DOE sites would be Pu(III)-EDTA, which only forms under anaerobic conditions. Research is therefore needed in this brand new project to investigate the biotransformation of Pu and Pu-EDTA under anaerobic conditions. The biotransformation of Pu and Pu-EDTA under various anaerobic regimes is poorly understood including the reduction kinetics of Pu(IV) to Pu(III) from soluble (Pu(IV)-EDTA) and insoluble Pu(IV) as PuO2(am) by metal reducing bacteria, the redox conditions required for this reduction, the strength of the Pu(III)-EDTA complex, how the Pu(III)-EDTA complex competes with other dominant anoxic soluble metals (e.g., Fe(II)), and the oxidation kinetics of Pu(III)-EDTA. Finally, the formation of a stable soluble Pu(III)-EDTA complex under anaerobic conditions would require degradation of the EDTA complex to limit Pu(III) transport in geologic environments. Anaerobic EDTA degrading microorganisms have not been isolated. These knowledge gaps preclude the development of a mechanistic understanding of how anaerobic conditions will influence Pu and Pu-EDTA fate and transport to assess, model, and design approaches to stop

  18. Phototrophic Growth and Accumulation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate by Purple Nonsulfur Bacterium Rhodopseudomonas palustris SP5212

    Directory of Open Access Journals (Sweden)

    M. Mukhopadhyay


    Full Text Available The ability of the phototrophic bacterium Rhodopseudomonas palustris SP5212 to produce polyhydroxyalkanoates (PHAs, poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] in particular was, assessed in acetate medium supplemented with hydroxybutyrate and valerate as cosubstrates. The isolate accumulated the polymer accounting for some 49.06% and 30% of cell dry weight when grown in hydroxybutyrate and valerate, respectively. PHA accumulation as well as 3HV monomer incorporation (30 mol% was maximum at 0.1% hydroxybutyrate, while valerate at 0.1% and 0.3% was suitable for total polymer accumulation and 3HV monomer incorporation, respectively. Cosupplementation of hydroxybutyrate and valerate in the ratio of 3 : 1 led to the accumulation of PHA accounting for 54% of cell dry weight, which contained more than 50 mol% of 3HV monomer. Moreover, the biphasic cultivation conditions with hydroxybutyrate as cosubstrate have improved the quality as well as quantity of the accumulated copolymer significantly.

  19. Life at extreme limits: the anaerobic halophilic alkalithermophiles. (United States)

    Mesbah, Noha M; Wiegel, Juergen


    The ability of anaerobic microorganisms to proliferate under extreme conditions is of widespread importance for microbial physiology, remediation, industry, and evolution. The halophilic alkalithermophiles are a novel group of polyextremophiles. Tolerance to alkaline pH, elevated NaCl concentrations, and high temperatures necessitates mechanisms for cytoplasmic pH acidification; permeability control of the cell membrane; and stability of proteins, the cell wall, and other cellular constituents to multiple extreme conditions. Although it is generally assumed that extremophiles growing at more than one extreme combine adaptive mechanisms for each individual extreme, adaptations for individual extremes often counteract each other. However, in alkaline, hypersaline niches heated via intense solar irradiation, culture-independent analyses have revealed the presence of an extensive diversity of aerobic and anaerobic microorganisms belonging to Bacteria and Archaea that survive and grow under multiple harsh conditions. Thus, polyextremophiles must have developed novel adaptive strategies enabling them to grow and proliferate under multiple extreme conditions. The recent isolation of two novel anaerobic, halophilic alkalithermophiles, Natranaerobius thermophilus and Halonatronum saccharophilum, will provide a platform for detailed biochemical, genomic, and proteomic experiments, allowing a greater understanding of the novel adaptive mechanisms undoubtedly employed by polyextremophiles. In this review, we highlight growth characteristics, ecology, and phylogeny of the anaerobic halophilic alkalithermophiles isolated. We also describe the bioenergetic and physiological problems posed by growth at the multiple extreme conditions of alkaline pH, high NaCl concentration, and elevated temperature under anoxic conditions and highlight recent findings and unresolved problems regarding adaptation to multiple extreme conditions.

  20. Anaerobic Bacteremia: Impact of Inappropriate Therapy on Mortality (United States)

    Lee, Yangsoon; Park, Yongjung; Kim, Myungsook; Choi, Jun Yong; Yong, Dongeun; Jeong, Seok Hoon


    Background Investigation on incidence and mortality of anaerobic bacteremia (AB) is clinically relevant in spite of its infrequent occurrence and not often explored, which report varies according to period and institutions. Therefore, it is necessary to analyze the incidence and risk factors related to mortality and assess clinical outcomes of AB in current aspect. Materials and Methods Characteristics of AB patients and anaerobic bacteria from blood culture at a university hospital in 2012 were reviewed retrospectively. The correlation between risk factors and 28-day patient mortality was analyzed. Results A total of 70 non-duplicated anaerobic bacteria were isolated from blood of 70 bacteremia patients in 2012. The history of cardiovascular disease as host's risk factor was statistically significant (P = 0.0344) in univariate and multivariate analysis. Although the inappropriate therapy was not statistically significant in univariate and multivariate analysis, the survival rate of bacteremia was significantly worse in patients who had inappropriate therapy compared with those underwent appropriate therapy (hazard ratio, 5.4; 95% confidence interval, 1.7–6.9; P = 0.004). The most frequently isolated organism was Bacteroides fragilis (32 isolates, 46%), followed by Bacteroides thetaiotaomicron (10, 14%), and non-perfringens Clostridium (7, 10%). Conclusion The incidence of AB in 2012 was 2.3% (number of AB patients per 100 positive blood culture patients) and the mortality rate in patients with clinically significant AB was 21.4%. In addition, AB was frequently noted in patients having malignancy and the survival rate of AB was significantly worse in patients who received inappropriate therapy compared with those underwent appropriate therapy. PMID:27433379

  1. Model-Based Feasibility Assessment of Membrane Biofilm Reactor to Achieve Simultaneous Ammonium, Dissolved Methane, and Sulfide Removal from Anaerobic Digestion Liquor (United States)

    Chen, Xueming; Liu, Yiwen; Peng, Lai; Yuan, Zhiguo; Ni, Bing-Jie


    In this study, the membrane biofilm reactor (MBfR) is proposed to achieve simultaneous removal of ammonium, dissolved methane, and sulfide from main-stream and side-stream anaerobic digestion liquors. To avoid dissolved methane stripping, oxygen is introduced through gas-permeable membranes, which also from the substratum for the growth of a biofilm likely comprising ammonium oxidizing bacteria (AOB), anaerobic ammonium oxidation (Anammox) bacteria, denitrifying anaerobic methane oxidation (DAMO) microorganisms, aerobic methane oxidizing bacteria (MOB), and sulfur oxidizing bacteria (SOB). A mathematical model is developed and applied to assess the feasibility of such a system and the associated microbial community structure under different operational conditions. The simulation studies demonstrate the feasibility of achieving high-level (>97.0%), simultaneous removal of ammonium, dissolved methane, and sulfide in the MBfRs from both main-stream and side-stream anaerobic digestion liquors through adjusting the influent surface loading (or hydraulic retention time (HRT)) and the oxygen surface loading. The optimal HRT was found to be inversely proportional to the corresponding oxygen surface loading. Under the optimal operational conditions, AOB, DAMO bacteria, MOB, and SOB dominate the biofilm of the main-stream MBfR, while AOB, Anammox bacteria, DAMO bacteria, and SOB coexist in the side-stream MBfR to remove ammonium, dissolved methane, and sulfide simultaneously.

  2. Characterization of membrane foulants at ambient temperature anaerobic membrane bioreactor treating low-strength industrial wastewater

    DEFF Research Database (Denmark)

    Zarebska, Agata; Kjerstadius, Hamse; Petrinic, Irena


    with anaerobic biological treatment at low temperature could not only reduce the operational cost of AD, but also alleviate environmental problems. However, at low temperature the AnMBR may suffer more fouling due to the increased extracellular polymeric substances production excreted by bacteria hampering......The large volume of industrial low-strength wastewaters has a potential for biogas production through conventional anaerobic digestion (AD), limited though by the need of heating and concentrating of the wastewaters. The use of anaerobic membrane bioreactor (AnMBR) combining membrane filtration...... the application of the process for the industrial wastewater treatment. In order to solve or reduce the fouling problem it is necessary to have a good insight into the processes that take place both on and in the membrane pores during filtration. Therefore, the objective of this study is to contribute to a better...

  3. Toxicity and biodegradability of olive mill wastewaters in batch anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Hamdi, M. (Centre de Biotechnologie, Sfax (Tunisia) Universite de Provence, Marseille (France))


    The anaerobic biodegradability and toxicity of olive mill wastewaters (OMW) were studied in batch anaerobic digestion experiments. Anaerobic digestion of OMW or the supernatant of its centrifugation, the methane production was achieved at up to 5-15% (V/V) dilution corresponding to only 5-20 g/L COD. The washed suspended solids of OMW were toxic at up to 80 g/L COD; however, the kinetic of biodegradability of OMW or the supernatant was faster than for suspended solids, which are constituted mealy of cellulose and lignin. The darkly colored polyphenols induce the problem of biodegradation of OMW, whereas the long chain fatty acids (LCFA), tannins and simple phenolic compounds are responsible for its toxicity for methanogenic bacteria. 26 refs., 4 figs., 1 tab.

  4. Decrease in anaerobe-related bacteraemias and increase in Bacteroides species isolation rate from 1998 to 2007: a retrospective study. (United States)

    Lazarovitch, Tsilia; Freimann, Sarit; Shapira, Galina; Blank, Helena


    Conflicting data have accumulated in recent years regarding the incidence of anaerobic bacteraemias. The aim of this study was to determine the prevalence of bacteraemias due to anaerobic bacteria and evaluate the importance of anaerobic blood cultures in a university hospital in Israel. A retrospective survey which focused on anaerobic blood culture bottles was performed on blood cultures received in our laboratory during the decade from January 1998 to December 2007. Anaerobic-related bacteraemias decreased during that period, whereas a significant increase was observed in Bacteroides species isolated from the blood cultures (from 18% during 1998-2002 to 43% during 2003-2007). Comparison of the medical records of 54 patients with Bacteroides-related bacteraemia during the two end periods (1998-1999 and 2006-2007) revealed a marked increase in complex underlying diseases. Hypertension and diabetes mellitus type II were found in 29% of the patients in 1998-1999 and increased to 43-45% of the patients in 2006-2007. Ischemic heart disease also increased from 14% of the patients in 1998-1999 to 43% in 2006-2007. We conclude that although positive anaerobic blood cultures account for a small percentage of positive blood samples, the growing involvement of Bacteroides species-related bacteraemias together with an increase in complex underlying diseases in these patients emphasize the importance of anaerobic blood cultures, particularly in patients with co-morbidities.

  5. Invasion of dentinal tubules by oral bacteria. (United States)

    Love, R M; Jenkinson, H F


    Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.

  6. Relationships between anaerobic consortia and removal efficiencies in an UASB reactor degrading 2,4 dichlorophenol (DCP). (United States)

    Sponza, Delia Teresa; Cigal, Canan


    To gain more insight into the interactions between anaerobic bacteria and reactor performances (chemical oxygen demand-COD, 2,4 dichlorophenol-2,4 DCP removals, volatile fatty acid-VFA, and methane gas productions) and how they depended on operational conditions the microbial variations in the anaerobic granular sludge from an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 DCP was studied. The study was composed of two parts. In the first part, the numbers of methanogens and acedogens in the anaerobic granular sludge were counted at different COD removal efficiencies. The relationships between the numbers of methanogens, the methane gas production and VFA production were investigated. The COD removal efficiencies increased to 74% from 30% while the number of total acedogens decreased to 10 from 30 cfu ml(-1). The number of total methanogens and acedogens varied between 11 x 10(3) and 10 x 10(9)MPN g(-1) and 10 and 30 cfu ml(-1) as the 2,4 DCP removal efficiencies were obtained between 60% and 99%, respectively. It was seen that, as the number of total acedogens decreased, the COD removal efficiencies increased. However, the number of total methanogens increased as the COD removal efficiencies increased. Correlations between the bacterial number and with the removal efficiencies obtained in different operational conditions were investigated. From the results presented in this paper a high correlation between the number of bacteria, COD removals, methane gas percentage, 2,4 DCP removals and VFA was observed. In the second part, methanogen bacteria in the anaerobic granular sludge were identified. Microbial observations and biochemical tests were applied to identify the anaerobic microorganisms from the anaerobic granular sludge. In the reactor treating 2,4 DCP, Methanobacterium bryantii, Methanobacterium formicicum, Methanobrevibacter smithii, Methanococcus voltae, Methanosarcina mazei, Methanosarcina acetivorans, Methanogenium bourgense and

  7. Properties of cellulose micro/nanofibers obtained from eucalyptus pulp fiber treated with anaerobic digestate and high shear mixing (United States)

    High production costs remain the single greatest factor limiting wider use of cellulose micro/nanofibers in the industry. The objective of the present study was to investigate the potential of using a low-cost bacteria-rich digestate (liquid anaerobic digestate – AD supernatant) on milled eucalyptus...

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

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


    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.

  9. Molecular ecology of anaerobic reactor systems

    DEFF Research Database (Denmark)

    Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter;


    Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

  10. Evaluation of a prereduced anaerobically sterilized medium (PRAS II) system for identification anaerobic microorganisms. (United States)

    Beaucage, C M; Onderdonk, A B


    A prereduced, anaerobically sterilized system of tubed media (PRAS II; Scott Laboratories, Fiskeville, R.I.) was evaluated for accuracy in the identification of anerobic microorganisms. PRAS II was found to be a rapid and accurate identification system for obligate anaerobes which does not require the use of gas cannula inoculation or incubation in a special anaerobic environment.

  11. Evaluation of a prereduced anaerobically sterilized medium (PRAS II) system for identification anaerobic microorganisms.


    Beaucage, C M; Onderdonk, A B


    A prereduced, anaerobically sterilized system of tubed media (PRAS II; Scott Laboratories, Fiskeville, R.I.) was evaluated for accuracy in the identification of anerobic microorganisms. PRAS II was found to be a rapid and accurate identification system for obligate anaerobes which does not require the use of gas cannula inoculation or incubation in a special anaerobic environment.

  12. Antarctic strict anaerobic microbiota from Deschampsia antarctica vascular plants rhizosphere reveals high ecology and biotechnology relevance. (United States)

    Peixoto, Rafael José Marques; Miranda, Karla Rodrigues; Lobo, Leandro Araujo; Granato, Alessandra; de Carvalho Maalouf, Pedro; de Jesus, Hugo Emiliano; Rachid, Caio T C C; Moraes, Saulo Roni; Dos Santos, Henrique Fragoso; Peixoto, Raquel Silva; Rosado, Alexandre Soares; Domingues, Regina Maria Cavalcanti Pilotto


    The Antarctic soil microbial community has a crucial role in the growth and stabilization of higher organisms, such as vascular plants. Analysis of the soil microbiota composition in that extreme environmental condition is crucial to understand the ecological importance and biotechnological potential. We evaluated the efficiency of isolation and abundance of strict anaerobes in the vascular plant Deschampsia antarctica rhizosphere collected in the Antarctic's Admiralty Bay and associated biodiversity to metabolic perspective and enzymatic activity. Using anaerobic cultivation methods, we identified and isolated a range of microbial taxa whose abundance was associated with Plant Growth-Promoting Bacteria (PGPB) and presences were exclusively endemic to the Antarctic continent. Firmicutes was the most abundant phylum (73 %), with the genus Clostridium found as the most isolated taxa. Here, we describe two soil treatments (oxygen gradient and heat shock) and 27 physicochemical culture conditions were able to increase the diversity of anaerobic bacteria isolates. Heat shock treatment allowed to isolate a high percentage of new species (63.63 %), as well as isolation of species with high enzymatic activity (80.77 %), which would have potential industry application. Our findings contribute to the understanding of the role of anaerobic microbes regarding ecology, evolutionary, and biotechnological features essential to the Antarctic ecosystem.

  13. Study of the role of anaerobic metabolism in succinate production by Enterobacter aerogenes. (United States)

    Tajima, Yoshinori; Kaida, Kenichi; Hayakawa, Atsushi; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Fudou, Ryosuke; Matsui, Kazuhiko; Usuda, Yoshihiro; Sode, Koji


    Succinate is a core biochemical building block; optimizing succinate production from biomass by microbial fermentation is a focus of basic and applied biotechnology research. Lowering pH in anaerobic succinate fermentation culture is a cost-effective and environmentally friendly approach to reducing the use of sub-raw materials such as alkali, which are needed for neutralization. To evaluate the potential of bacteria-based succinate fermentation under weak acidic (pH Enterobacter aerogenes AJ110637, which rapidly assimilates glucose at pH 5.0. Based on the profile of anaerobic products, we constructed single-gene knockout mutants to eliminate the main anaerobic metabolic pathways involved in NADH re-oxidation. These single-gene knockout studies showed that the ethanol synthesis pathway serves as the dominant NADH re-oxidation pathway in this organism. To generate a metabolically engineered strain for succinate production, we eliminated ethanol formation and introduced a heterogeneous carboxylation enzyme, yielding E. aerogenes strain ΔadhE/PCK. The strain produced succinate from glucose with a 60.5% yield (grams of succinate produced per gram of glucose consumed) at pH <6.2 and anaerobic conditions. Thus, we showed the potential of bacteria-based succinate fermentation under weak acidic conditions.

  14. Bacterial community composition and abundance in leachate of semi-aerobic and anaerobic landfills

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Bo Yue; Qi Wang; Zechun Huang; Qifei Huang; Zengqiang Zhang


    The abundance and phylogenetic composition of bacterial community in leachate of semi-aerobic and anaerobic landfill were compared through real-time polymerase chain reaction and denaturing gradient gel electrophoresis.In semi-aerobic landfill scenario,the bacterial 16S rRNA copy numbers in leachate had no significant reduction from initial stage to stable period.In the scenario of anaerobic landfill,the largest bacterial 16S rRNA gene copy number was found in leachate at initial stage,but it reduced significantly at stable period.Moreover,methane-oxidizing bacteria population in stable period was lower than that in initial period in both two landfill processes.However,semi-aerobic landfill leachate had more methanotrophic bacteria populations than that in the anaerobic one.Furthermore,according to the sequences and phylogenetic analysis,obvious difference could be detected in bacterial community composition in different scenarios.Proteobacteria and bacteroidetes took up a dominantly higher proportion in semi-aerobic landfill leachate.To summarize up,different landfill methods and its landfill ages had crucial impacts on bacterial abundance and composition in leachate of semi-aerobic and anaerobic landfills.

  15. Effect of thermal hydrolysis and ultrasounds pretreatments on foaming in anaerobic digesters. (United States)

    Alfaro, N; Cano, R; Fdz-Polanco, F


    Foam appears regularly in anaerobic digesters producing operational and safety problems. In this research, based on the operational observation at semi-industrial pilot scale where sludge pretreatment mitigated foaming in anaerobic digesters, this study aimed at evaluating any potential relationship between foaming tools applied to activated sludge at lab-scale (foam potential, foam stability and Microthrix parvicella abundance) and the experimental behavior observed in pilot scale and full-scale anaerobic digesters. The potential of thermal hydrolysis and ultrasounds for reducing foaming capacity was also evaluated. Filamentous bacteria abundance was directly linked to foaming capacity in anaerobic processes. A maximum reduction of M.parvicella abundance (from 5 to 2) was reached using thermal hydrolysis with steam explosion at 170°C and ultrasounds at 66.7kWh/m(3), showing both good anti-foaming properties. On the other hand, foam potential and stability determinations showed a lack of consistency with the bacteria abundance results and experimental evidences.

  16. Azoarcus sp. CIB, an anaerobic biodegrader of aromatic compounds shows an endophytic lifestyle.

    Directory of Open Access Journals (Sweden)

    Helga Fernández

    Full Text Available BACKGROUND: Endophytic bacteria that have plant growth promoting traits are of great interest in green biotechnology. The previous thought that the Azoarcus genus comprises bacteria that fit into one of two major eco-physiological groups, either free-living anaerobic biodegraders of aromatic compounds or obligate endophytes unable to degrade aromatics under anaerobic conditions, is revisited here. METHODOLOGY/PRINCIPAL FINDINGS: Light, confocal and electron microscopy reveal that Azoarcus sp. CIB, a facultative anaerobe β-proteobacterium able to degrade aromatic hydrocarbons under anoxic conditions, is also able to colonize the intercellular spaces of the rice roots. In addition, the strain CIB displays plant growth promoting traits such nitrogen fixation, uptake of insoluble phosphorus and production of indoleacetic acid. Therefore, this work demonstrates by the first time that a free-living bacterium able to degrade aromatic compounds under aerobic and anoxic conditions can share also an endophytic lifestyle. The phylogenetic analyses based on the 16S rDNA and nifH genes confirmed that obligate endophytes of the Azoarcus genus and facultative endophytes, such as Azoarcus sp. CIB, locate into different evolutionary branches. CONCLUSIONS/SIGNIFICANCE: This is the first report of a bacterium, Azoarcus sp. CIB, able to degrade anaerobically a significant number of aromatic compounds, some of them of great environmental concern, and to colonize the rice as a facultative endophyte. Thus, Azoarcus sp. CIB becomes a suitable candidate for a more sustainable agricultural practice and phytoremediation technology.

  17. Thermophilic fermentative bacteria from a deep borehole in granitic rock in Sweden (United States)

    Szewzyk, Ulrich; Szewzyk, Regine; Stenstroem, Thor-Axel


    A borehole drilled to a final depth of 6779 m in granitic rock in Gravberg, Sweden, was sampled and examined for the presence and activity of anaerobic bacteria. The application of anaerobic enrichment and isolation techniques resulted in pure cultures of various fermenting bacteria. Growth in enrichment cultures was observed only in those cultures inoculated from water samples from a depth of 3500 m. Pure cultures of anaerobic, fermenting bacteria were obtained with the following substrates: glucose, starch, xylane, ethanol, and lactate. All isolated bacteria were so far undiscribed bacteria by means of their physiological properties. One strain of the glucose fermenting bacteria was further characterized concerning its phylogenetic position and was found to be closest related to Clostridium thermohydrosulfuricum. However, by means of its characteristic metabolism, it was clearly separated from C. thermohydrosulfuricum. No sulfate-reducing or methanogenic bacteria were found in any of the samples. Fermentative bacteria growing in the presence of hematite often reduced the iron and induced the formation and deposition of insoluble iron sulfides.

  18. Zero valent iron simultaneously enhances methane production and sulfate reduction in anaerobic granular sludge reactors. (United States)

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie


    Zero valent iron (ZVI) packed anaerobic granular sludge reactors have been developed for improved anaerobic wastewater treatment. In this work, a mathematical model is developed to describe the enhanced methane production and sulfate reduction in anaerobic granular sludge reactors with the addition of ZVI. The model is successfully calibrated and validated using long-term experimental data sets from two independent ZVI-enhanced anaerobic granular sludge reactors with different operational conditions. The model satisfactorily describes the chemical oxygen demand (COD) removal, sulfate reduction and methane production data from both systems. Results show ZVI directly promotes propionate degradation and methanogenesis to enhance methane production. Simultaneously, ZVI alleviates the inhibition of un-dissociated H2S on acetogens, methanogens and sulfate reducing bacteria (SRB) through buffering pH (Fe(0) + 2H(+) = Fe(2+) + H2) and iron sulfide precipitation, which improve the sulfate reduction capacity, especially under deterioration conditions. In addition, the enhancement of ZVI on methane production and sulfate reduction occurs mainly at relatively low COD/ [Formula: see text] ratio (e.g., 2-4.5) rather than high COD/ [Formula: see text] ratio (e.g., 16.7) compared to the reactor without ZVI addition. The model proposed in this work is expected to provide support for further development of a more efficient ZVI-based anaerobic granular system.

  19. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor (United States)

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


    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.

  20. Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Rahayu, Suparni Setyowati, E-mail: [Doctoral Program in Environmental Science, University of Diponegoro, Semarang (Indonesia); Department of Mechanical Engineering, State Polytechnic of Semarang, Semarang Indonesia (Indonesia); Purwanto,, E-mail:; Budiyono, E-mail: [Doctoral Program in Environmental Science, University of Diponegoro, Semarang (Indonesia); Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Semarang Indonesia (Indonesia)


    The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH{sub 4}/g COD and produce biogas containing of CH{sub 4}: 81.23% and CO{sub 2}: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

  1. Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater (United States)

    Rahayu, Suparni Setyowati; Purwanto, Budiyono


    The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH4/g COD and produce biogas containing of CH4: 81.23% and CO2: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

  2. Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids. (United States)

    Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi


    In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

  3. Diversity of Cultured Thermophilic Anaerobes in Hot Springs of Yunnan Province, China (United States)

    Lin, L.; Lu, Y.; Dong, X.; Liu, X.; Wei, Y.; Ji, X.; Zhang, C.


    Thermophilic anaerobes including Archaea and Bacteria refer to those growing optimally at temperatures above 50°C and do not use oxygen as the terminal electron acceptor for growth. Study on thermophilic anaerobes will help to understand how life thrives under extreme conditions. Meanwhile thermophilic anaerobes are of importance in potential application and development of thermophilic biotechnology. We have surveyed culturable thermophilic anaerobes in hot springs (pH6.5-7.5; 70 - 94°C) in Rehai of Tengchong, Bangnazhang of Longlin, Eryuan of Dali,Yunnan, China. 50 strains in total were cultured from the hot springs water using Hungate anaerobic technique, and 30 strains were selected based on phenotypic diversity for analysis of 16S rDNA sequences. Phylogenetic analysis showed that 28 strains belonged to the members of five genera: Caldanaerobacter, Calaramator, Thermoanaerobacter, Dictyoglomus and Fervidobacterium, which formed five branches on the phylogenetic tree. Besides, 2 strains of methanogenic archaea were obtained. The majority of the isolates were the known species, however, seven strains were identified as novel species affiliated to the five genera based on the lower 16S rDNA sequence similarities (less than 93 - 97%) with the described species. This work would provide the future study on their diversity, distribution among different regions and the potential application of thermophilic enzyme. Supported by State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences(SKLMR-080605)and the Foundation of State Natural Science (30660009, 30960022, 31081220175).

  4. Genetics and Molecular Biology of Hydrogen Metabolism in Sulfate-Reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)


    The degradation of our environment and the depletion of fossil fuels make the exploration of alternative fuels evermore imperative. Among the alternatives is biohydrogen which has high energy content by weight and produces only water when combusted. Considerable effort is being expended to develop photosynthetic systems -- algae, cyanobacteria, and anaerobic phototrophs -- for sustainable H2 production. While promising, this approach also has hurdles such as the harvesting of light in densely pigmented cultures that requires costly constant mixing and large areas for exposure to sunlight. Little attention is given to fermentative H2 generation. Thus understanding the microbial pathways to H2 evolution and metabolic processes competing for electrons is an essential foundation that may expand the variety of fuels that can be generated or provide alternative substrates for fine chemical production. We studied a widely found soil anaerobe of the class Deltaproteobacteria, a sulfate-reducing bacterium to determine the electron pathways used during the oxidation of substrates and the potential for hydrogen production.

  5. Genetics and Molecular Biology of Hydrogen Metabolism in Sulfate-Reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [University of Missouri-Columbia


    The degradation of our environment and the depletion of fossil fuels make the exploration of alternative fuels evermore imperative. Among the alternatives is biohydrogen which has high energy content by weight and produces only water when combusted. Considerable effort is being expended to develop photosynthetic systems -- algae, cyanobacteria, and anaerobic phototrophs -- for sustainable H2 production. While promising, this approach also has hurdles such as the harvesting of light in densely pigmented cultures that requires costly constant mixing and large areas for exposure to sunlight. Little attention is given to fermentative H2 generation. Thus understanding the microbial pathways to H2 evolution and metabolic processes competing for electrons is an essential foundation that may expand the variety of fuels that can be generated or provide alternative substrates for fine chemical production. We studied a widely found soil anaerobe of the class Deltaproteobacteria, a sulfate-reducing bacterium to determine the electron pathways used during the oxidation of substrates and the potential for hydrogen production.

  6. Performance of mesophilic anaerobic granules for removal of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    An Chunjiang [Department of Environmental Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); He Yanling [Department of Environmental Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Huang Guohe, E-mail: [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); Sino-Canada Research Academy of Energy and Environmental Studies, North China Electric Power University, Beijing 102206 (China); Liu Yonghong [Department of Environmental and Chemical Engineering, Xi' an Polytechnic University, Xi' an 710048 (China)


    The performance of mesophilic anaerobic granules to degrade octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) was investigated under various conditions. The results of batch experiments showed that anaerobic granules were capable of removing HMX from aqueous solution with high efficiency. Both biotic and abiotic mechanisms contributed to the removal of HMX by anaerobic granules under mesophilic conditions. Adsorption appeared to play a significant role in the abiotic process. Furthermore, HMX could be biodegraded by anaerobic granules as the sole substrate. After 16 days of incubation, 99.04% and 96.42% of total HMX could be removed by 1 g VSS/L acclimated and unacclimated granules, respectively. Vancomycin, an inhibitor of acetogenic bacteria, caused a significant inhibition of HMX biotransformation, while 2-bromoethanesulfonic acid, an inhibitor of methanogenic bacteria, only resulted in a slight decrease of metabolic activity. The presence of the glucose, as a suitable electron donor and carbon source, was found to enhance the degradation of HMX by anaerobic granules. Our study showed that sulfate had little adverse effects on biotransformation of HMX by anaerobic granules. However, nitrate had significant inhibitory effect on the extent of HMX removal especially in the initial period. This study offered good prospects of using high-rate anaerobic technology in the treatment of munition wastewater.

  7. [Aerobic and aero-anaerobic bacterial flora of the nasal cavities of lambs]. (United States)

    Menoueri, N; Richard, Y; Brunet, J; Oudar, J


    On the basis of bacteriological examinations carried out on 415 intranasal swabs, aerobic and aero-anaerobic respiratory microbes were studied in lambs. A great diversity of bacteria has been found (in total 35 bacterial species and genus have been identified). This flora is characterised by the presence of gram positive cocci with a gram negative strain included in genus Moraxella and connected with Moraxella bovis species.

  8. The physicochemical characteristics and anaerobic degradability of desiccated coconut industry waste water. (United States)

    Chanakya, H N; Khuntia, Himanshu Kumar; Mukherjee, Niranjan; Aniruddha, R; Mudakavi, J R; Thimmaraju, Preeti


    Desiccated coconut industries (DCI) create various intermediates from fresh coconut kernel for cosmetic, pharmaceutical and food industries. The mechanized and non-mechanized DCI process between 10,000 and 100,000 nuts/day to discharge 6-150 m(3) of malodorous waste water leading to a discharge of 264-6642 kg chemical oxygen demand (COD) daily. In these units, three main types of waste water streams are coconut kernel water, kernel wash water and virgin oil waste water. The effluent streams contain lipids (1-55 g/l), suspended solids (6-80 g/l) and volatile fatty acids (VFA) at concentrations that are inhibitory to anaerobic bacteria. Coconut water contributes to 20-50% of the total volume and 50-60% of the total organic loads and causes higher inhibition of anaerobic bacteria with an initial lag phase of 30 days. The lagooning method of treatment widely adopted failed to appreciably treat the waste water and often led to the accumulation of volatile fatty acids (propionic acid) along with long-chain unsaturated free fatty acids. Biogas generation during biological methane potential (BMP) assay required a 15-day adaptation time, and gas production occurred at low concentrations of coconut water while the other two streams did not appear to be inhibitory. The anaerobic bacteria can mineralize coconut lipids at concentrations of 175 mg/l; however; they are severely inhibited at a lipid level of ≥350 mg/g bacterial inoculum. The modified Gompertz model showed a good fit with the BMP data with a simple sigmoid pattern. However, it failed to fit experimental BMP data either possessing a longer lag phase and/or diauxic biogas production suggesting inhibition of anaerobic bacteria.

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

    Directory of Open Access Journals (Sweden)

    Enea Gino Di Domenico


    Full Text Available 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.

  10. Carbon monoxide conversion by anaerobic bioreactor sludges

    NARCIS (Netherlands)

    Sipma, J.; Stams, A.J.M.; Lens, P.N.L.; Lettinga, G.


    Seven different anaerobic sludges from wastewater treatment reactors were screened for their ability to convert carbon monoxide (CO) at 30 and 55degreesC
    Seven different anaerobic sludges from wastewater treatment reactors were screened for their ability to convert carbon monoxide (CO) at 30 and

  11. Anaerobic critical velocity in four swimming techniques. (United States)

    Neiva, H P; Fernandes, R J; Vilas-Boas, J P


    The aim of this study was to assess critical velocity in order to control and evaluate anaerobic swimming training. 51 highly trained male swimmers performed maximal 15, 25, 37.5 and 50 m in the 4 swimming techniques to determine critical velocity from the distance-time relationship. Anaerobic critical velocity was compared with 100 m swimming performance and corresponding partials. Complementarily, 9 swimmers performed a 6×50 m (4 min interval) training series at front crawl individual anaerobic critical velocity, capillary blood lactate concentrations being assessed after each repetition. The mean±SD values of anaerobic critical velocity and its relationship with the 100 m event were: 1.61±0.07 (r=0.60, p=0.037), 1.53±0.05 (r=0.81, p=0.015), 1.33±0.05 (r=0.83, p=0.002), and 1.75±0.05 (r=0.74, p=0.001), for butterfly, backstroke, breaststroke and front crawl, respectively. However, differences between anaerobic critical velocity and performance were observed (with exception of the second half of the 100 m swimming events in breaststroke and butterfly). Lactate concentration values at the end of the series were 14.52±1.06 mmol.l (-1), which suggests that it was indeed an anaerobic training set. In this sense, anaerobic critical velocity can be used to prescribe anaerobic training intensities.

  12. Integrated anaerobic and aerobic treatment of sewage.

    NARCIS (Netherlands)

    Kaijun Wang,


    This thesis describes results of investigations dealing with sequential concept of anaerobic-aerobic treatment of municipal wastewater. The main purposes of the study were 1) to develop a proper anaerobic hydrolytic pretreatment unit, consisting of a Hydrolysis Upflow Sludge Bed (HUSB-) reactor and

  13. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær


    increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  14. Prospects of Anaerobic Digestion Technology in China

    Institute of Scientific and Technical Information of China (English)


    As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

  15. Toxicants inhibiting anaerobic digestion: a review. (United States)

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


    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.

  16. Enzymes involved in the anaerobic oxidation of n-alkanes: from methane to long-chain paraffins

    Directory of Open Access Journals (Sweden)

    Amy V. Callaghan


    Full Text Available Anaerobic microorganisms play key roles in the biogeochemical cycling of methane and non-methane alkanes. To date, there appear to be at least three proposed mechanisms of anaerobic methane oxidation (AOM. The first pathway is mediated by consortia of archaeal anaerobic methane oxidizers and sulfate-reducing bacteria via ‘reverse methanogenesis’ and is catalyzed by a homologue of methyl-coenzyme M reductase. The second pathway is also mediated by anaerobic methane oxidizers and sulfate-reducing bacteria, wherein the archaeal members catalyze both methane oxidation and sulfate reduction and zero-valent sulfur is a key intermediate. The third AOM mechanism is a nitrite-dependent, intra-aerobic pathway described for the denitrifying bacterium, ‘Candidatus Methylomirabilis oxyfera.’ It is hypothesized that AOM proceeds via reduction of nitrite to nitric oxide, followed by the conversion of two nitric oxide molecules to dinitrogen and molecular oxygen. The latter can be used to functionalize the methane via a particulate methane monooxygenase. With respect to non-methane alkanes, there also appears to be novel mechanisms of activation. The most well-described pathway is the addition of non-methane alkanes across the double bond of fumarate to form alkyl-substituted succinates via the putative glycyl radical enzyme, alkylsuccinate synthase (also known as methylalkylsuccinate synthase. Other proposed mechanisms include anaerobic hydroxylation via ethylbenzene dehydrogenase-like enzymes and an ‘intra-aerobic’ denitrification pathway similar to that described for ‘M. oxyfera.’

  17. Massive nitrogen loss from the Benguela upwelling system through anaerobic ammonium oxidation RID B-8834-2011

    DEFF Research Database (Denmark)

    Kuypers, MMM; Lavik, G.; Woebken, D.;


    ) and is commonly attributed to denitrification (reduction of nitrate to N-2 by heterotrophic bacteria). Here, we show that instead, the anammox process (the anaerobic oxidation of ammonium by nitrite to yield N-2) is mainly responsible for nitrogen loss in the OMZ waters of one of the most productive regions...... that anammox bacteria are responsible for massive losses of fixed nitrogen. We have identified and directly linked anammox bacteria to the removal of fixed inorganic nitrogen in the OMZ waters of an open-ocean setting. We hypothesize that anammox could also be responsible for substantial nitrogen loss from...... other OMZ waters of the ocean....

  18. The inhibition of Clostridium botulinum type C by other bacteria in wetland sediments (United States)

    Sandler, Renee J.; Rocke, Tonie E.; Yuill, Thomas M.


    Bacteria with inhibitory activity against Clostridium botulinum type C were isolated from 32% of sediment samples (n = 1600) collected from 10 marshes in a northern California wetland over a 12 mo period. Aerobic and anaerobic bacteria with inhibitory activity were isolated from 12% and 23% of the samples, respectively. Bacteria with inhibitory activity were isolated from all 10 study sites and throughout the year. This study demonstrates that bacteria with inhibitory activity against C. botulinum type C occur naturally in wetland sediments.

  19. Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify

    Energy Technology Data Exchange (ETDEWEB)

    Boulêtreau, Stéphanie, E-mail: [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Lyautey, Emilie [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Dubois, Sophie [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France); Compin, Arthur [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Delattre, Cécile; Touron-Bodilis, Aurélie [EDF Recherche et Développement, LNHE (Laboratoire National d' Hydraulique et Environnement), 6 quai Watier, F-78401 Chatou (France); Mastrorillo, Sylvain [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Garabetian, Frédéric [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France)


    Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+ 2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB). We used water warming associated to the immediate thermal release of a nuclear power plant cooling circuit to produce natural PRB assemblages on glass slides while testing 2 temperatures (mean temperature of 17 °C versus 19.5 °C). PRB were sampled at 2 sampling times during PRB accretion (6 and 21 days) in both temperatures. Bacterial community composition was assessed using ARISA. Denitrifier community abundance and denitrification gene mRNA levels were estimated by q-PCR and qRT-PCR, respectively, of 5 genes encoding catalytic subunits of the denitrification key enzymes. Denitrification enzyme activity (DEA) was measured by the acetylene-block assay at 20 °C. A mean water warming of 2.5 °C was sufficient to produce contrasted total bacterial and denitrifier communities and, therefore, to affect DEA. Indirect temperature effect on DEA may have varied between sampling time, increasing by up to 10 the denitrification rate of 6-day-old PRB and decreasing by up to 5 the denitrification rate of 21-day-old PRB. The present results suggest that indirect effects of warming through changes in bacterial community composition, coupled to the strong direct effect of temperature on DEA already demonstrated in PRB, could modulate dissolved nitrogen removal by denitrification in rivers and streams. - Highlights: •We produced river biofilms in 2 mean temperature conditions: 17 vs 19.5 °C. •We compared their denitrifiers' structuring and functioning in 6d- and 21d-old biofilms. •A difference of 2.5 °C produced contrasted denitrifier communities. •The indirect temperature effect on denitrification activity shifted between biofilm age.

  20. An advanced anaerobic biofilter with effluent recirculation for phenol removal and methane production in treatment of coal gasification wastewater. (United States)

    Li, Yajie; Tabassum, Salma; Zhang, Zhenjia


    An advanced anaerobic biofilter (AF) was introduced for the treatment of coal gasification wastewater (CGW), and effluent recirculation was adopted to enhance phenol removal and methane production. The results indicated that AF was reliable in treating diluted CGW, while its efficiency and stability were seriously reduced when directly treating raw CGW. However, its performance could be greatly enhanced by effluent recirculation. Under optimal effluent recirculation of 0.5 to the influent, concentrations of chemical oxygen demand (COD) and total phenol in the effluent could reach as low as 234.0 and 14.2mg/L, respectively. Also, the rate of methane production reached 169.0mLCH4/L/day. Though CGW seemed to restrain the growth of anaerobic microorganisms, especially methanogens, the inhibition was temporary and reversible, and anaerobic bacteria presented strong tolerance. The activities of methanogens cultivated in CGW could quickly recover on feeding with glucose wastewater (GW). However, the adaptability of anaerobic bacteria to the CGW was very poor and the activity of methanogens could not be improved by long-term domestication. By analysis using the Haldane model, it was further confirmed that high effluent recirculation could result in high activity for hydrolytic bacteria and substrate affinity for toxic matters, but only suitable effluent recirculation could result in high methanogenic activity.

  1. Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation (United States)

    Brocks, Jochen J.; Schaeffer, Philippe


    Carbonates of the 1640 million years (Ma) old Barney Creek Formation (BCF), McArthur Basin, Australia, contain more than 22 different C 40 carotenoid derivatives including lycopane, γ-carotane, β-carotane, chlorobactane, isorenieratane, β-isorenieratane, renieratane, β-renierapurpurane, renierapurpurane and the monoaromatic carotenoid okenane. These biomarkers extend the geological record of carotenoid derivatives by more than 1000 million years. Okenane is potentially derived from the red-colored aromatic carotenoid okenone. Based on a detailed review of the ecology and physiology of all extant species that are known to contain okenone, we interpret fossil okenane as a biomarker for planktonic purple sulfur bacteria of the family Chromatiaceae. Okenane is strictly a biomarker for anoxic and sulfidic conditions in the presence of light (photic zone euxinia) and indicates an anoxic/oxic transition (temporarily) located at less than 25 m depth and, with a high probability, less than 12 m depth. For the BCF, we also interpret renierapurpurane, renieratane and β-renierapurpurane as biomarkers for Chromatiaceae with a possible contribution of cyanobacterial synechoxanthin to the renierapurpurane pool. Although isorenieratane may, in principle, be derived from actinobacteria, in the BCF these biomarkers almost certainly derive from sulfide-oxidizing phototrophic green sulfur bacteria (Chlorobiaceae). Biological precursors of γ-carotane, β-carotane and lycopane are found among numerous autotrophic and almost all phototrophic organisms in the three domains of life. In the BCF, a paucity of diagnostic eukaryotic steroids suggests that algae were rare and, therefore, that cyanobacterial carotenoids such as β-carotene, echinenone, canthaxanthin and zeaxanthin are the most likely source of observed β-carotane. γ-Carotane may be derived from cyanobacteria, Chlorobiaceae and green non-sulfur bacteria (Chloroflexi), while the most likely biological sources for lycopane

  2. Effect of increasing total solids contents on anaerobic digestion of food waste under mesophilic conditions: performance and microbial characteristics analysis.

    Directory of Open Access Journals (Sweden)

    Jing Yi

    Full Text Available The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.

  3. Hygiene tests in the anaerobic digestion of household refuse

    Energy Technology Data Exchange (ETDEWEB)

    Maier, H.; Philipp, W.; Wekerle, J.; Strauch, D.

    In a pilot plant the disinfecting effect of composting the effluent of an anaerobic mesophilic digestion process of the organic fraction of household refuse was investigated. The dewatered effluent was mixed with straw as bulking material, put in not aerated windrows and aerobically composted. It was further investigated whether the influent of the digester could be disinfected with lime milk prior to the anaerobic mesophilic digestion process. For the evaluation of the disinfection salmonellas, enterococci, klebsiellas, parvo-, polio- and rotavirus were used as test agents. Temperature, total aerobic germ count, enterobacteriaceae and coliforms were also considered. The effect of lime milk in the influent on the digestion process, survival of the test bacteria and gas production was also studied. Both treatments can result in a hygienically safe product. But composting under the conditions given should not be operated during the winter period. Lime treatment of the influent results in a disinfection of the effluent which immediately can be utilized as liquid sludge in agriculture. (orig.)

  4. Cellulosomes - promising supramolecular machines of anaerobic cellulolytic microorganisms. (United States)

    Vodovnik, Maša; Marinšek-Logar, Romana


    Cellulose is the main structural component of plant cell wall and thus the most abundant carbohydrate in nature. However, extracting the energy from this abundant source is limited by its recalcitrant nature. The hydrolysis of plant cell wall requires synergystic action of different enzymes, including multiple cellulases, hemicellulases, pectinases, etc. Meanwhile aerobic cellulolytic microorganisms release large quantities of synergistically acting free enzymes in their environment, most anaerobic microorganisms evolved more efficient strategies to optimize the process of plant cell wall degradation, for example production of extracellular multi-enzyme complexes (cellulosomes). Cellulosomes consist of at least one core structural protein, named scaffoldin, which firmly binds numerous enzymatic subunits, and usually also plays a major role in substrate binding. Although the general structure of cellulosomes seems universal, differences in number and identity of complex components do exist among microorganisms. The article surveys the current knowledge about cellulosomes, focusing on three best investigated cellulolytic clostridia, one representative of ruminal bacteria and novel findings concerning anaerobic fungi. Efforts in construction of artificially engineered cellulosomal systems (designer cellulosomes) as well as their biotechnological potential are also discussed.

  5. Hydrolytic activity of alpha-amylase in anaerobic digested sludge. (United States)

    Higuchi, Y; Ohashi, A; Imachi, H; Harada, H


    Hydrolysis is usually considered to be a rate-limiting step in anaerobic digestion. For improving anaerobic solid waste treatments, it is essential to elucidate the mechanism of hydrolysis. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism of hydrolysis. Alpha-amylase activity of solid starch-degrading bacteria (SDB) was estimated through batch experiments with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Monitoring of newly isolated strains of SDB was done by fluorescence in situ hybridization. Results indicated that cell-bound alpha-amylase is chiefly responsible for the hydrolysis in the digested sludge, providing very useful information that the contact between microbial cells and solids is significantly important. The activity of alpha-amylase of the digested sludge remained quite low when not required, but increased as they recognized appropriate substrates. Several-fold higher activity was obtained for starch or maltose as compared to glucose only.

  6. Anaerobic ammonium oxidation in a bioreactor treating slaughterhouse wastewater

    Directory of Open Access Journals (Sweden)

    V. Reginatto


    Full Text Available Ammonium oxidation was thought to be an exclusively aerobic process; however, as recently described in the literature, it is also possible under anaerobic conditions and this process was named ANAMMOX. This work describes the operation of a system consisting of a denitrifying reactor coupled to a nitrifying reactor used for removal of nitrogen from slaughterhouse wastewater. During operation of the denitrifying reactor an average nitrogen ammonium removal rate of 50 mg/Ld was observed. This biomass was used to seed a second reactor, operated in repeated fed batch mode, fed with synthetic medium specific to the growth of bacteria responsible for the ANAMMOX process. The nitrogen loading rate varied between 33 and 67 mgN/Ld and average nitrogen removal was 95% and 40%, respectively. Results of fluorescence in situ hybridization (FISH confirmed the presence of anammox-like microorganisms in the enriched biomass.

  7. Vertical distribution and anaerobic biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments in Hong Kong, South China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun-Hua [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Zhou, Hong-Wei [Department of Environmental Health Science, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou (China); Wong, Yuk-Shan [Department of Biology, The Hong Kong University of Science and Technology (Hong Kong); Tam, Nora Fung-Yee, E-mail: [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)


    The vertical distribution of polycyclic aromatic hydrocarbons (PAHs) at different sediment depths, namely 0-2 cm, 2-4 cm, 4-6 cm, 6-10 cm, 10-15 cm and 15-20 cm, in one of the most contaminated mangrove swamps, Ma Wan, Hong Kong was investigated. It was the first time to study the intrinsic potential of deep sediment to biodegrade PAHs under anaerobic conditions and the abundance of electron acceptors in sediment for anaerobic degradation. Results showed that the total PAHs concentrations (summation of 16 US EPA priority PAHs) increased with sediment depth. The lowest concentration (about 1300 ng g{sup -1} freeze-dried sediment) and the highest value (around 5000 ng g{sup -1} freeze-dried sediment) were found in the surface layer (0-2 cm) and deeper layer (10-15 cm), respectively. The percentage of high molecular weight (HMW) PAHs (4 to 6 rings) to total PAHs was more than 89% at all sediment depths. The ratio of phenanthrene to anthracene was less than 10 while fluoranthene to pyrene was around 1. Negative redox potentials (Eh) were recorded in all of the sediment samples, ranging from - 170 to - 200 mv, with a sharp decrease at a depth of 6 cm then declined slowly to 20 cm. The results suggested that HMW PAHs originated from diesel-powered fishing vessels and were mainly accumulated in deep anaerobic sediments. Among the electron acceptors commonly used by anaerobic bacteria, sulfate was the most dominant, followed by iron(III), nitrate and manganese(IV) was the least. Their concentrations also decreased with sediment depth. The population size of total anaerobic heterotrophic bacteria increased with sediment depth, reaching the peak number in the middle layer (4-6 cm). In contrast, the aerobic heterotrophic bacterial count decreased with sediment depth. It was the first time to apply a modified electron transport system (ETS) method to evaluate the bacterial activities in the fresh sediment under PAH stress. The vertical drop of the ETS activity suggested that

  8. Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

    KAUST Repository

    Meulepas, Roel J W


    Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study.

  9. The impacts of triclosan on anaerobic community structures, function, and antimicrobial resistance. (United States)

    McNamara, Patrick J; LaPara, Timothy M; Novak, Paige J


    Triclosan is a widespread antimicrobial agent that accumulates in anaerobic digesters used to treat the residual solids generated at municipal wastewater treatment plants; there is very little information, however, about how triclosan impacts microbial communities in anaerobic digesters. We investigated how triclosan impacts the community structure, function and antimicrobial resistance genes in lab-scale anaerobic digesters. Previously exposed (to triclosan) communities were amended with 5, 50, and 500 mg/kg of triclosan, corresponding to the median, 95th percentile, and 4-fold higher than maximum triclosan concentration that has been detected in U.S. biosolids. Triclosan amendment caused all of the Bacteria and Archaea communities to structurally diverge from that of the control cultures (based on ARISA). At the end of the experiment, all triclosan-amended Archaea communities had diverged from the control communities, regardless of the triclosan concentration added. In contrast, over time the Bacteria communities that were amended with lower concentrations of triclosan (5 mg/kg and 50 mg/kg) initially diverged and then reconverged with the control community structure. Methane production at 500 mg/kg was nearly half the methane production in control cultures. At 50 mg/kg, a large variability in methane production was observed, suggesting that 50 mg/kg may be a tipping point where function begins to fail in some communities. When previously unexposed communities were exposed to 500 mg triclosan/kg, function was maintained, but the abundance of a gene encoding for triclosan resistance (mexB) increased. This research suggests that triclosan could inhibit methane production in anaerobic digesters if concentrations were to increase and may also select for resistant Bacteria. In both cases, microbial community composition and exposure history alter the influence of triclosan.

  10. Biomarkers of Microbial Metabolism for Monitoring in-situ Anaerobic PAH Degradation (United States)

    Young, L.; Phelps, C.; Battistelli, J.


    Monoaromatic and polycyclic aromatic compounds found in petroleum and its products are subject to biodegradation in the absence of oxygen. These anaerobic pathways reveal novel mechanism of microbial transformation through a series of metabolites and intermediates which are unique to the anaerobic degradation process. The presence of these compounds in-situ, then conceptually can serve as indicators that anaerobic degradation is taking place. We have laboratory studies and field samples which support this concept for BTX and PAH compounds. Environments in which these anaerobic degradation processes have been observed include freshwater and estuarine sediments, groundwater from impacted aquifers at a former manufactured gas plant and gasoline station, and a creosote-contaminated aquifer. Analytical protocols were developed to detect nanomolar concentrations from soil slurries and groundwater samples and microcosm studies verified their formation from field samples and use as biomarkers of activity. Recent studies on the mechanisms of anaerobic naphthalene and methylnaphthalene metabolism have identified several unusual compounds that can serve as biomarkers for monitoring in situ PAH biodegradation. For naphthalene these include 2-naphthoic acid (2-NA), tetrahydro-2-naphthoic acid (TH-2-NA), hexahydro-2-naphthoic acid (HH-2-NA) and methylnaphthoic acid (MNA) generated by sulfate-reducing bacteria degrading naphthalene or methylnaphthalene. Groundwater samples were analyzed from wells distributed throughout an anaerobic, creosote-contaminated aquifer and also from a leaking underground storage site. Samples were extracted, derivatized and analyzed by GC/MS. The concentration of 2-NA at each monitoring well was quantified and correlated to the zones of naphthalene contamination. Taken together with measurements of the aquifer's physical characteristics, these bio