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Sample records for autotrophs

  1. Freshwater autotrophic picoplankton: a review

    Directory of Open Access Journals (Sweden)

    John G. STOCKNER

    2002-02-01

    Full Text Available Autotrophic picoplankton (APP are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

  2. Autotrophic ammonia oxidation by soil thaumarchaea

    OpenAIRE

    Zhang, Li-Mei; Offre, Pierre R.; He, Ji-Zheng; Verhamme, Daniel T.; Nicol, Graeme W.; Prosser, James I.

    2010-01-01

    Nitrification plays a central role in the global nitrogen cycle and is responsible for significant losses of nitrogen fertilizer, atmospheric pollution by the greenhouse gas nitrous oxide, and nitrate pollution of groundwaters. Ammonia oxidation, the first step in nitrification, was thought to be performed by autotrophic bacteria until the recent discovery of archaeal ammonia oxidizers. Autotrophic archaeal ammonia oxidizers have been cultivated from marine and thermal spring environments, bu...

  3. Clostridium difficile is an autotrophic bacterial pathogen.

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    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  4. Mannitol in six autotrophic stramenopiles and Micromonas.

    Science.gov (United States)

    Dittami, Simon M; Aas, Hoai T N; Paulsen, Berit S; Boyen, Catherine; Edvardsen, Bente; Tonon, Thierry

    2011-08-01

    Mannitol plays a central role in brown algal physiology since it represents an important pathway used to store photoassimilate. Several specific enzymes are directly involved in the synthesis and recycling of mannitol, altogether forming the mannitol cycle. The recent analysis of algal genomes has allowed tracing back the origin of this cycle in brown seaweeds to a horizontal gene transfer from bacteria, and furthermore suggested a subsequent transfer to the green microalga Micromonas. Interestingly, genes of the mannitol cycle were not found in any of the currently sequenced diatoms, but were recently discovered in pelagophytes and dictyochophytes. In this study, we quantified the mannitol content in a number of ochrophytes (autotrophic stramenopiles) from different classes, as well as in Micromonas. Our results show that, in accordance with recent observations from EST libraries and genome analyses, this polyol is produced by most ochrophytes, as well as the green alga tested, although it was found at a wide range of concentrations. Thus, the mannitol cycle was probably acquired by a common ancestor of most ochrophytes, possibly after the separation from diatoms, and may play different physiological roles in different classes. PMID:21720212

  5. Biogas desulfurization using autotrophic denitrification process.

    Science.gov (United States)

    Bayrakdar, Alper; Tilahun, Ebrahim; Calli, Baris

    2016-01-01

    The aim of this study was to evaluate the performance of an autotrophic denitrification process for desulfurization of biogas produced from a chicken manure digester. A laboratory scale upflow fixed bed reactor (UFBR) was operated for 105 days and fed with sodium sulfide or H2S scrubbed from the biogas and nitrate as electron donor and acceptor, respectively. The S/N ratio (2.5 mol/mol) of the feed solution was kept constant throughout the study. When the UFBR was fed with sodium sulfide solution with an influent pH of 7.7, about 95 % sulfide and 90 % nitrate removal efficiencies were achieved. However, the inlet of the UFBR was clogged several times due to the accumulation of biologically produced elemental sulfur particles and the clogging resulted in operational problems. When the UFBR was fed with the H2S absorbed from the biogas and operated with an influent pH of 8-9, around 98 % sulfide and 97 % nitrate removal efficiencies were obtained. In this way, above 95 % of the H2S in the biogas was removed as elemental sulfur and the reactor effluent was reused as scrubbing liquid without any clogging problem. PMID:26428238

  6. Estimating autotrophic respiration in streams using daily metabolism data

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    Knowing the fraction of gross primary production (GPP) that is immediately respired by autotrophs and their closely associated heterotrophs (ARf) is necessary to understand the trophic base and carbon spiraling in streams. We show a means to estimate ARf from daily metabolism da...

  7. Autotrophic acetyl coenzyme A biosynthesis in Methanococcus maripaludis

    International Nuclear Information System (INIS)

    To detect autotrophic CO2 assimilation in cell extracts of Methanococcus maripaludis, lactate dehydrogenase and NADH were added to convert pyruvate formed from autotropically synthesized acetyl coenzyme A to lactate. The lactate produced was determined spectrophotometrically. When CO2 fixation was pulled in the direction of lactate synthesis, CO2 reduction to methane was inhibited. Bromoethanesulfonate (BES), a potent inhibitor of methanogenesis, enhanced lactate synthesis, and methyl coenzyme M inhibited it in the absence of BES. Lactate synthesis was dependent on CO2 and H2, but H2 + CO2-independent synthesis was also observed. In cell extracts, the rate of lactate synthesis was about 1.2 nmol min-1 mg of protein-1. When BES was added, the rate of lactate synthesis increased to 2.1 nmol min-1 mg of protein-1. Because acetyl coenzyme A did not stimulate lactate synthesis, pyruvate synthase may have been the limiting activity in these assays. Radiolabel from 14CO2 was incorporated into lactate. The percentages of radiolabel in the C-1, C-2, and C-3 positions of lactate were 73, 33, and 11%, respectively. Both carbon monoxide and formaldehyde stimulated lactate synthesis. 14CH2O was specifically incorporated into the C-3 of lactate, and 14CO was incorporated into the C-1 and C-2 positions. Low concentrations of cyanide also inhibited autotrophic growth, CO dehydrogenase activity, and autotrophic lactate synthesis. These observations are in agreement with the acetogenic pathway of autotrophic CO2 assimilation

  8. Denitrification characteristics of a sulfur autotrophic denitrification reactor

    Directory of Open Access Journals (Sweden)

    Chenxiao ZHANG

    2016-02-01

    Full Text Available The denitrification characteristics of a sulfur autotrophic denitrification reactor are investigated. The results show that domestication of sulfur autotrophic bacteria is completed within 15 days after biofilm formation in the reactor, which is shorter than other similar researches. The nitrogen removal rate remains over than 90%, and the denitrification rate reaches 18.5 mg N/(L·h with influent NO-3-N of 70 mg/L , influent pH of 8 and HRT of 4.3 h . Thiobacillus denitrificans are observed in the whole reactor when domestication finishes, while it is more abundant in the middle and lower part. The optimal influent NO-3-N concentration for the reactor is 50 mg/L, the optimal temperature is 30~35 ℃, the optimal influent pH is 7~8, and the nitrogen removal rate is over than 90%.

  9. Photo-autotrophic Production of Poly(hydroxyalkanoates) in Cyanobacteria

    OpenAIRE

    Drosg, B.; Fritz, I; Gattermayr, F.; Silvestrini, L.

    2015-01-01

    In the last two decades, poly(hydroxyalkanoates) (PHA) were solely produced using heterotrophic bacteria in aerobic cultivation. With respect to the great potential (500 Mt yr–1) of raw industrial CO2 streams and even greater potential of flue gases, the focus on photo-autotrophic biotechnological processes is increasing steadily. Primarily, PHA-gene transfer from heterotrophic bacteria into algae and plant cells was attempted, with the intention to combine the known biosynthesis pathway with...

  10. Autotrophic growth of nitrifying community in an agricultural soil

    OpenAIRE

    Xia, Weiwei; Zhang, Caixia; Zeng,Xiaowei; Feng, Youzhi; Weng, Jiahua; Lin, Xiangui; Zhu, Jianguo; Xiong, Zhengqin; Xu, Jian; Cai, Zucong; Jia, Zhongjun

    2011-01-01

    The two-step nitrification process is an integral part of the global nitrogen cycle, and it is accomplished by distinctly different nitrifiers. By combining DNA-based stable isotope probing (SIP) and high-throughput pyrosequencing, we present the molecular evidence for autotrophic growth of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB) in agricultural soil upon ammonium fertilization. Time-course incubation of SIP microcosms indicated t...

  11. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    OpenAIRE

    B. Veuger; Pitcher, A.; Schouten, S.; Sinninghe Damsté, J.S.; Middelburg, J. J.

    2013-01-01

    Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absen...

  12. Lipid-based liquid biofuels from autotrophic microalgae: energetic and environmental performance

    NARCIS (Netherlands)

    L. Reijnders

    2013-01-01

    Commercial cultivation of autotrophic microalgae for food production dates back to the 1950s. Autotrophic microalgae have also been proposed as a source for lipid-based liquid biofuels. As yet, there is no commercial production of such biofuels and estimated near-term prices are far in excess of fos

  13. Autotrophic nitrogen removal in one lab-scale vertical submerged biofilm reactor

    Science.gov (United States)

    Liang, Zhiwei; Chen, Yingxu; Li, Wenhong; Yang, Shangyuan; Du, Ping

    In this study, the process performance of a new vertical submerged biofilm reactor for complete autotrophic ammonia removal was investigated using synthetic wastewater. The main objectives of this study were to evaluate the flexibility of the reactor, achieve partial autotrophic nitrification with influent ammonium nitrogen ranging from 40 to 280 mg L -1, and achieve a stable half partial autotrophic nitrification by controlling hydraulic retention time (HRT) and alkalinity. A very low concentration of nitrate was observed in the effluent during nitrification. Then autotrophic denitrification revealed Anammox bacteria were present and active in the central anaerobic parts of the bioreactor which was inoculated with a mixed microbial consortium from activated sludge. The results of this study demonstrated that autotrophic denitrification processes can coexist with heterotrophic denitrifying processes in the same environment even if Anammox bacteria were less competitive than heterotrophic denitrifying bacteria.

  14. Autotrophic and heterotrophic activity in Arctic first-year sea ice: seasonal study from Malene Bight, SW Greenland

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Kristensen, Morten; Rysgaard, Søren; Glud, Ronnie Nøhr; Hansen, Per Juel; Hillingsøe, Karen Marie

    2010-01-01

    followed by an algal bloom in late March and April, leading to a net autotrophic community. During February and March, the oxygen level in the bag incubations remained constant, validating the low balanced heterotrophic and autotrophic activity. As the autotrophic activity exceeded the heterotrophic...

  15. Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

    OpenAIRE

    Meijer, Wilhelmus Gerhardus

    1990-01-01

    Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O), pbosphoribulokinase (PRK) and fructosebisphosphatase (FBPase) are the unique enzymes of this autotrophic pathway (Chapter 1). ... Zie: Summary

  16. Current views on the regulation of autotrophic carbon dioxide fixation via the Calvin cycle in bacteria

    OpenAIRE

    Dijkhuizen, L; Harder, W

    1984-01-01

    The Calvin cycle of carbon dioxide fixation constitutes a biosynthetic pathway for the generation of (multi-carbon) intermediates of central metabolism from the one-carbon compound carbon dioxide. The product of this cycle can be used as a precursor for the synthesis of all components of cell material. Autotrophic carbon dioxide fixation is energetically expensive and it is therefore not surprising that in the various groups of autotrophic bacteria the operation of the cycle is under strict m...

  17. Investigation of mixotrophic, heterotrophic, and autotrophic growth of Chlorella vulgaris under agricultural waste medium.

    Science.gov (United States)

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-01-01

    Growth of Chlorella vulgaris and its lipid production were investigated under autotrophic, heterotrophic, and mixotrophic conditions. Cheap agricultural waste molasses and corn steep liquor from industries were used as carbon and nitrogen sources, respectively. Chlorella vulgaris grew remarkably under this agricultural waste medium, which resulted in a reduction in the final cost of the biodiesel production. Maximum dry weight of 2.62 g L(-1) was obtained in mixotrophic growth with the highest lipid concentration of 0.86 g L(-1). These biomass and lipid concentrations were, respectively, 140% and 170% higher than autotrophic growth and 300% and 1200% higher than heterotrophic growth. In mixotrophic growth, independent or simultaneous occurrence of autotrophic and heterotrophic metabolisms was investigated. The growth of the microalgae was observed to take place first heterotrophically to a minimum substrate concentration with a little fraction in growth under autotrophic metabolism, and then the cells grew more autotrophically. It was found that mixotrophic growth was not a simple combination of heterotrophic and autotrophic growth. PMID:25807048

  18. Morphology and physiology of facultative autotrophic coryneformic bacteria with ability of carbon monoxide oxidation

    International Nuclear Information System (INIS)

    Two coryneform bacterial strains (IFAM 1131 and IFAM 1133) capable of living on CO as the sole energy and carbon source were selected from a number of co-tolerant bacteria and studied more closely. Both strains could provisionally be grouped in the genera Arthrobacter. Their ability for hetorotrophic growth with a variety of C-sources and also autotrophic growth under CO and H2 atmospheric conditions characterised the test strains as facultative autotrophs. They could clearly be distinguished from all other CO- and H2-autotrophic bacterial strains described in the literature. Studies on strain IFAM 1131 using 14CO shared that for CO-autotrophic growth, carbon monoxide is oxidised to CO2. Ribulose 1,5-bisphosphate carboxylase activity, only found in autotrophically - grown cells, provided evidence for CO2 as the C-source and its fixation via the calvin cycle. The CO-oxidising system was also active in the absence of CO2. Gas chromatographically determined conversion rates for CO-autotrophically-grown static cultures of the strain IFAM 1131 revealed that some 20% of the CO oxidised to CO2 was fixed during logarithmic growth. (orig./MG)

  19. Expanding leaves of mature deciduous forest trees rapidly become autotrophic.

    Science.gov (United States)

    Keel, Sonja G; Schädel, Christina

    2010-10-01

    Emerging leaves in evergreen tree species are supplied with carbon (C) from the previous year's foliage. In deciduous trees, no older leaves are present, and the early phase of leaf development must rely on C reserves from other tissues. How soon developing leaves become autotrophic and switch from being C sinks to sources has rarely been studied in mature forest trees, and simultaneous comparisons of species are scarce. Using a canopy crane and a simple (13)CO(2)-pulse-labelling technique, we demonstrate that young leaves of mature trees in three European deciduous species (Fagus sylvatica L., Quercus petraea (Matt.) Liebl., Tilia platyphyllos Scop.) start assimilating CO(2) at a very early stage of development (10-50% expanded). One month after labelling, all leaves were still strongly (13)C enriched, suggesting that recent photosynthates had been incorporated into slow turnover pools such as cellulose or lignin and thus had contributed to leaf growth. In line with previous studies performed at the same site, we found stronger incorporation of recent photosynthates into growing tissues of T. platyphyllos compared with F. sylvatica and Q. petraea. Non-structural carbohydrate (NSC) concentrations analysed for one of the three study species (F. sylvatica) showed that sugar and starch pools rapidly increased during leaf development, suggesting that newly developed leaves soon produce more NSC than can be used for growth. In conclusion, our findings indicate that expanding leaves of mature deciduous trees become C autonomous at an early stage of development despite the presence of vast amounts of mobile carbohydrate reserves. PMID:20688879

  20. Sulfide-driven autotrophic denitrification significantly reduces N2O emissions.

    Science.gov (United States)

    Yang, Weiming; Zhao, Qing; Lu, Hui; Ding, Zhi; Meng, Liao; Chen, Guang-Hao

    2016-03-01

    The Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI) process build on anaerobic carbon conversion through biological sulfate reduction and autotrophic denitrification by using the sulfide byproduct from the previous reaction. This study confirmed extra decreases in N2O emissions from the sulfide-driven autotrophic denitrification by investigating N2O reduction, accumulation, and emission in the presence of different sulfide/nitrate (S/N) mass ratios at pH 7 in a long-term laboratory-scale granular sludge autotrophic denitrification reactor. The N2O reduction rate was linearly proportional to the sulfide concentration, which confirmed that no sulfide inhibition of N2O reductase occurred. At S/N = 5.0 g-S/g-N, this rate resulted by sulfide-driven autotrophic denitrifying granular sludge (average granule size = 701 μm) was 27.7 mg-N/g-VSS/h (i.e., 2 and 4 times greater than those at 2.5 and 0.8 g-S/g-N, respectively). Sulfide actually stimulates rather than inhibits N2O reduction no matter what granule size of sulfide-driven autotrophic denitrifying sludge engaged. The accumulations of N2O, nitrite and free nitrous acid (FNA) with average granule size 701 μm of sulfide-driven autotrophic denitrifying granular sludge engaged at S/N = 5.0 g-S/g-N were 4.7%, 11.4% and 4.2% relative to those at 3.0 g-S/g-N, respectively. The accumulation of FNA can inhibit N2O reduction and increase N2O accumulation during sulfide-driven autotrophic denitrification. In addition, the N2O gas emission level from the reactor significantly increased from 14.1 ± 0.5 ppmv (0.002% of the N load) to 3707.4 ± 36.7 ppmv (0.405% of the N load) as the S/N mass ratio in the influent decreased from 2.1 to 1.4 g-S/g-N over the course of the 120-day continuous monitoring period. Sulfide-driven autotrophic denitrification may significantly reduce greenhouse gas emissions from biological nutrient removal when sulfur conversion processes are applied. PMID

  1. Woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process for nitrate contaminated water remediation.

    Science.gov (United States)

    Li, Rui; Feng, Chuanping; Hu, Weiwu; Xi, Beidou; Chen, Nan; Zhao, Baowei; Liu, Ying; Hao, Chunbo; Pu, Jiaoyang

    2016-02-01

    Nitrate contaminated water can be effectively treated by simultaneous heterotrophic and autotrophic denitrification (HAD). In the present study, woodchips and elemental sulfur were used as co-electron donors for HAD. It was found that ammonium salts could enhance the denitrifying activity of the Thiobacillus bacteria, which utilize the ammonium that is produced by the dissimilatory nitrate reduction to ammonium (DNRA) in the woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process. The denitrification performance of the WSHAD process (reaction constants range from 0.05485 h(-1) to 0.06637 h(-1)) is better than that of sulfur-based autotrophic denitrification (reaction constants range from 0.01029 h(-1) to 0.01379 h(-1)), and the optimized ratio of woodchips to sulfur is 1:1 (w/w). No sulfate accumulation is observed in the WSHAD process and the alkalinity generated in the heterotrophic denitrification can compensate for alkalinity consumption by the sulfur-based autotrophic denitrification. The symbiotic relationship between the autotrophic and the heterotrophic denitrification processes play a vital role in the mixotrophic environment. PMID:26650451

  2. Diversity and succession of autotrophic microbial community in high-elevation soils along deglaciation chronosequence.

    Science.gov (United States)

    Liu, Jinbo; Kong, Weidong; Zhang, Guoshuai; Khan, Ajmal; Guo, Guangxia; Zhu, Chunmao; Wei, Xiaojie; Kang, Shichang; Morgan-Kiss, Rachael M

    2016-10-01

    Global warming has resulted in substantial glacier retreats in high-elevation areas, exposing deglaciated soils to harsh environmental conditions. Autotrophic microbes are pioneering colonizers in the deglaciated soils and provide nutrients to the extreme ecosystem devoid of vegetation. However, autotrophic communities remain less studied in deglaciated soils. We explored the diversity and succession of the cbbL gene encoding the large subunit of form I RubisCO, a key CO2-fixing enzyme, using molecular methods in deglaciated soils along a 10-year deglaciation chronosequence on the Tibetan Plateau. Our results demonstrated that the abundance of all types of form I cbbL (IA/B, IC and ID) rapidly increased in young soils (0-2.5 years old) and kept stable in old soils. Soil total organic carbon (TOC) and total nitrogen (TN) gradually increased along the chronosequence and both demonstrated positive correlations with the abundance of bacteria and autotrophs, indicating that soil TOC and TN originated from autotrophs. Form IA/B autotrophs, affiliated with cyanobacteria, exhibited a substantially higher abundance than IC and ID. Cyanobacterial diversity and evenness increased in young soils (<6 years old) and then remained stable. Our findings suggest that cyabobacteria play an important role in accumulating TOC and TN in the deglaciated soils. PMID:27465079

  3. Elemental sulfur formation and nitrogen removal from wastewaters by autotrophic denitrifiers and anammox bacteria.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Yan, Laihong; Wang, Aijie; Gu, Yingying; Lee, Duu-Jong

    2015-09-01

    Elemental sulfur (S(0)) formation from and nitrogen removal on sulfide, nitrate and ammonium-laden wastewaters were achieved by denitrifying ammonium oxidation (DEAMOX) reactor with autotrophic denitrifiers and anaerobic ammonium oxidation (anammox) bacteria. The sulfide to nitrate ratio is a key process parameter for excess accumulation of S(0) and a ratio of 1.31:1 is a proposed optimum. The Alishewanella, Thauera and Candidatus Anammoximicrobium present respectively the autotrophic denitrifiers and anammox bacteria for the reactor. DEAMOX is demonstrated promising biological process for treating organics-deficient (S+N) wastewaters with excess S(0) production. PMID:26022701

  4. Effect of heterotrophic versus autotrophic food on feeding and reproduction of the calanoid copepod Acartia tonsa : relationship with prey fatty acid composition

    DEFF Research Database (Denmark)

    Broglio, E.; Jonasdottir, Sigrun; Calbet, A.; Jakobsen, Hans Henrik; Saiz, E.

    2003-01-01

    ) and ingestion rates, or as the quotient: EPR/ingestion rate. The diets, offered in monoculture, were the heterotrophic ciliates Strombidium sulcatum or Mesodinium pulex, the heterotrophic dinoflagellate Gymnodinium dominans, the autotrophic cryptophyte Rhodomonas salina and the autotrophic...

  5. Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

    NARCIS (Netherlands)

    Meijer, Wilhelmus Gerhardus

    1990-01-01

    Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O), pb

  6. Estimation of autotrophic soil respiration in a boreal forest using three different approaches

    Science.gov (United States)

    Kulmala, Liisa; Pumpanen, Jukka; Heinonsalo, Jussi

    2016-04-01

    It is generally challenging to separate autotrophic and heterotrophic soil respiration. The reason for these difficulties is connected with the intimate interaction of the key processes in soil. Root-associated microbes practically colonize the whole soil volume while decomposition processes occur in the same matrix. Therefore, autotrophic and heterotrophic processes cannot be separated in natural systems. However, there are several methods that can be used to better understand the dynamics of these two. A classical method is called 'trenching' where a trench is dug around a known volume of soil and the roots entering the soil are cut from the living trees thus blocking the C flow from them. The second way to separate autotrophic and heterotrophic respiration relies on the difference in the isotopic signature (13C) of plant-derived or decomposition-derived CO2. The third way to separate the sources is to study the differences in the short- and long-term temperature dependencies in CO2 soil emissions. This is possible especially in boreal forests where the biological activity has a strong seasonal cycle. We compared these three methods in an experiment conducted in a southern boreal middle-aged Scots pine stand in Finland. Our data provides a unique possibility to critically evaluate current methods for estimating autotrophic and heterotrophic soil respiration. The knowledge is needed to study further plant physiology and plant-microbe interactions in soil.

  7. Fluidization velocity assessment of commercially available sulfur particles for use in autotrophic denitrification biofilters

    Science.gov (United States)

    There has been no evaluation of sulfur-based autotrophic denitrification using fluidized biofilters in a recirculating aquaculture system to mitigate nitrate-nitrogen loads. The objectives of this work were to quantify the particle size distribution, specific surface area, and fluidization velocitie...

  8. Expression of Heterogenous Arsenic Resistance Genes in the Obligately Autotrophic Biomining Bacterium Thiobacillus ferrooxidans

    OpenAIRE

    Peng, Ji-Bin; Yan, Wang-Ming; Bao, Xue-Zhen

    1994-01-01

    Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation. The plasmids with the replicon of wide-host-range plasmid RSF1010 were stable in T. ferrooxidans. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacterium, but the promoter derived from T. ferrooxidans showed no special function in its original host.

  9. Autotrophic nitrogen removal from low strength waste water at low temperature

    NARCIS (Netherlands)

    Hendrickx, T.L.G.; Wang, Y.; Kampman, C.; Zeeman, G.; Temmink, B.G.; Buisman, C.J.N.

    2012-01-01

    Direct anaerobic treatment of municipal waste waters allows for energy recovery in the form of biogas. A further decrease in the energy requirement for waste water treatment can be achieved by removing the ammonium in the anaerobic effluent with an autotrophic process, such as anammox. Until now, an

  10. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    Directory of Open Access Journals (Sweden)

    Christine eSharp

    2012-08-01

    Full Text Available Genomic analysis of the methanotrophic verrucomicrobium Methylacidiphilum infernorum strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo, ‘universal’ pmoA polymerase chain reaction (PCR primers do not target these bacteria. Unlike proteobacterial methanotrophs, Methylacidiphilum fixes carbon autotrophically, and uses methane only for energy generation. As a result, techniques used to detect methanotrophs in the environment such as 13CH4-stable isotope probing (SIP and pmoA-targeted PCR do not detect verrucomicrobial methanotrophs, and they may have been overlooked in previous environmental studies. We developed a modified SIP technique to identify active methanotrophic verrucomicrobia in the environment by labelling with 13CO2 and 13CH4, individually and in combination. Testing the protocol in M. infernorum strain V4 resulted in assimilation of 13CO2 but not 13CH4, verifying its autotrophic lifestyle. To specifically detect methanotrophs (as opposed to other autotrophs via 13CO2-SIP, a quantitative PCR (qPCR assay specific for verrucomicrobial-pmoA genes was developed and used in combination with SIP. Incubation of an acidic, high-temperature geothermal soil with 13CH4 + 12CO2 caused little shift in the density distribution of verrucomicrobial-pmoA genes relative to controls. However, labelling with 13CO2 in combination with 12CH4 or 13CH4 induced a strong shift in the distribution of verrucomicrobial-pmoA genes towards the heavy DNA fractions. The modified SIP technique demonstrated that the primary methanotrophs active in the soil were autotrophs and belonged to the Verrucomicrobia. This is the first demonstration of autotrophic, non-proteobacterial methanotrophy in situ, and provides a tool to detect verrucomicrobial methanotrophs in other ecosystems.

  11. Stimulation of autotrophic denitrification by intrusions of the Bosporus Plume into the anoxic Black Sea

    Directory of Open Access Journals (Sweden)

    Clara A. Fuchsman

    2012-07-01

    Full Text Available Autotrophic denitrification was measured in the southwestern coastal Black Sea, where the Bosporus Plume injects oxidized chemical species (especially O2 and NO3- into the oxic, suboxic and anoxic layers. Prominent oxygen intrusions caused an overlap of NOx- and sulfide at the same station where autotrophic denitrification activity was detected with incubation experiments. Several bacteria that have been proposed to oxidize sulfide in other low oxygen environments were found in the Black Sea including SUP05, Sulfurimonas, Arcobacter, and BS-GSO2. Comparison of TRFLP profiles from this mixing zone station and the Western Gyre (a station not affected by the Bosporus Plume indicate the greatest relative abundance of Sulfurimonas and Arcobacter at the appropriate depths at the mixing zone station. The autotrophic gammaproteobacterium BS-GSO2 correlated with ammonium fluxes rather than with sulfide fluxes and the maximum in SUP05 peak height was shallower than the depths where autotrophic denitrification was detected. Notably, anammox activity was not detected at the mixing zone station, though low levels of DNA from the anammox bacteria Candidatus Scalindua were present. These results provide evidence for a modified ecosystem with different N2 production pathways in the southwest coastal region compared to that found in the rest of the Black Sea. Moreover, the same Sulfurimonas phylotype (BS139 was previously detected on >30 μm particles in the suboxic zone of the Western Gyre along with DNA of potential sulfate reducers, so it is possible that particle-attached autotrophic denitrification may be an overlooked N2 production pathway in the central Black Sea as well.

  12. Development of biological platform for the autotrophic production of biofuels

    Science.gov (United States)

    Khan, Nymul

    of the current status of metabolic engineering of chemolithoautotrophs is carried out in order to identify the challenges and likely routes to overcome them. This is presented in Chapter 3 of this dissertation. The initial metabolic engineering and bioreactor studies was carried out using a number of gene-constructs on R. capsulatus and R. eutropha. The gene-constructs consisted of Plac promoter followed by the triterpene synthase genes (SS or BS) and other upstream genes. A comparison of the production of triterpenes were done in the different growth modes that R. capsulatus was capable of growing---aerobic heterotrophic, anaerobic photoheterotrophic and aerobic chemoautotrophic. Autotrophic productivity could likely be improved much further by increasing the available mass-transfer of the reactor. These efforts are presented in Chapter 4 of this dissertation. (Abstract shortened by UMI.).

  13. Lactate dehydrogenase from autotrophic and heterotrophic cells of the marine diatom Cylindrotheca fusiformis Reimann & Lewin.

    Science.gov (United States)

    Darley, W M; Smiley, R H

    1976-10-01

    Cultures of Cylindrotheca furisormis grown either autotrohpically or heterotrophically on lactate contained significant amounts of NAD-dependent L(+)-lactate dehydrogenase (EC 1.1.1.27). Polyacylamide gel electrophoresis of crude enzyme extracts revealed a single band which was indistinguishable between autotrohpic and heterotrohpic cells. The Km for lactate of partially purified preparations was lower under heterotrophic conditions. The specific activity in crude extracts was higher under autotrophic than heterotrophic conditions; it dropped precipitously when autotrophic cells were transferred to the dark, increasing again only in the presence of lactate. These and related observations suggest that this enzyme has at most only a minor role in the assimilation of lactate during heterotrophic growth on lactate. PMID:184899

  14. Autotrophic microbe metagenomes and metabolic pathways differentiate adjacent red sea brine pools

    KAUST Repository

    Wang, Yong

    2013-04-29

    In the Red Sea, two neighboring deep-sea brine pools, Atlantis II and Discovery, have been studied extensively, and the results have shown that the temperature and concentrations of metal and methane in Atlantis II have increased over the past decades. Therefore, we investigated changes in the microbial community and metabolic pathways. Here, we compared the metagenomes of the two pools to each other and to those of deep-sea water samples. Archaea were generally absent in the Atlantis II metagenome; Bacteria in the metagenome were typically heterotrophic and depended on aromatic compounds and other extracellular organic carbon compounds as indicated by enrichment of the related metabolic pathways. In contrast, autotrophic Archaea capable of CO2 fixation and methane oxidation were identified in Discovery but not in Atlantis II. Our results suggest that hydrothermal conditions and metal precipitation in the Atlantis II pool have resulted in elimination of the autotrophic community and methanogens.

  15. Management of microbial community composition, architecture and performance in autotrophic nitrogen removing bioreactors through aeration regimes

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem

    Completely autotrophic nitrogen removal from nitrogen-rich wastewaters through the nitritation -plus- anaerobic ammonium oxidation processes can greatly reduce operational energy costs compared to traditional nitrogen removal processes. The footprint can be further reduced by process intensificat......Completely autotrophic nitrogen removal from nitrogen-rich wastewaters through the nitritation -plus- anaerobic ammonium oxidation processes can greatly reduce operational energy costs compared to traditional nitrogen removal processes. The footprint can be further reduced by process...... some of the collateral impacts could be isolated, increasing process understanding. It was demonstrated that aeration strategy can be used as a powerful tool to manipulate the microbial community composition, its architecture and reactor performance. We suggest operation via intermittent aeration with...

  16. Autotrophic and heterotrophic food sources of copepods in the Scheldt estuary as traced by stable C and N isotopes

    OpenAIRE

    L. De Brabandere

    2005-01-01

    Estuaries draining densely populated watersheds experience significant anthropogenic pressure and sustain large autotrophic and heterotrophic production owing to an increased input of nutrients and organic matter. Polluted estuaries are often net heterotrophic systems. Our objective was to study the relative contributionof autotrophic and heterotrophic food webs in sustaining the high productivity of pelagic estuarine ecosystems along the estuarine gradient of the Scheldt estuary. We concentr...

  17. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    OpenAIRE

    ChristineSharp; MatthewStott

    2012-01-01

    Genomic analysis of the methanotrophic verrucomicrobium “Methylacidiphilum infernorum” strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo), ‘universal’ pmoA polymerase chain reaction (PCR) primers do not target these bacteria. Unlike proteobacterial methanotrophs, “Methylacidiphilum” fixes carbon autotrophically...

  18. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    OpenAIRE

    Sharp, Christine E; Stott, Matthew B.; Dunfield, Peter F.

    2012-01-01

    Genomic analysis of the methanotrophic verrucomicrobium “Methylacidiphilum infernorum” strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo), “universal” pmoA polymerase chain reaction (PCR) primers do not target these bacteria. Unlike proteobacterial methanotrophs, “Methylacidiphilum” fixes carbon autotrophically...

  19. Expression of Heterogenous Arsenic Resistance Genes in the Obligately Autotrophic Biomining Bacterium Thiobacillus ferrooxidans.

    Science.gov (United States)

    Peng, J B; Yan, W M; Bao, X Z

    1994-07-01

    Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation. The plasmids with the replicon of wide-host-range plasmid RSF1010 were stable in T. ferrooxidans. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacterium, but the promoter derived from T. ferrooxidans showed no special function in its original host. PMID:16349341

  20. Autotrophic Ammonia-Oxidizing Bacteria Contribute Minimally to Nitrification in a Nitrogen-Impacted Forested Ecosystem

    OpenAIRE

    Jordan, F L; Cantera, JJL; Fenn, M E; Stein, L.Y.

    2005-01-01

    Deposition rates of atmospheric nitrogenous pollutants to forests in the San Bernardino Mountains range east of Los Angeles, California, are the highest reported in North America. Acidic soils from the west end of the range are N-saturated and have elevated rates of N-mineralization, nitrification, and nitrate leaching. We assessed the impact of this heavy nitrogen load on autotrophic ammonia-oxidizing communities by investigating their composition, abundance, and activity. Analysis of 177 cl...

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

    OpenAIRE

    Pongsak (Lek) Noophan; Chalermraj Wantawin; Siriporn Sripiboon; Sanya Sirivitayapakorn

    2008-01-01

    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 accep...

  2. Modeling, Experimentation, and Control of Autotrophic Nitrogen Removal in Granular Sludge Systems

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine

    is convenient for treating anaerobic digester liquor, landfill leachate, or special industrial wastewaters, because costs related to the need for aeration and carbon addition are lowered by 60% and 100%, respectively, compared to conventional nitrification denitrification treatment. Energy and......Complete autotrophic nitrogen removal (CANR) is a novel process that can increase the treatment capacity for wastewaters containing high concentrations of nitrogen and low organic carbon to nitrogen ratios, through an increase of the volumetric removal rate by approximately five times. This process...

  3. Partitioning Longleaf Pine Soil Respiration into Its Heterotrophic and Autotrophic Components through Root Exclusion

    OpenAIRE

    Althea A. ArchMiller; Lisa J. Samuelson

    2016-01-01

    Rapid and accurate estimations of the heterotrophic and autotrophic components of total soil respiration (Rs) are important for calculating forest carbon budgets and for understanding carbon dynamics associated with natural and management-related disturbances. The objective of this study was to use deep (60 cm) root exclusion tubes and paired control (i.e., no root exclusion) collars to estimate heterotrophic respiration (Rh) and Rs, respectively, in three 26-year-old longleaf pine (Pinus pal...

  4. Fate of 14C-labeled microbial products derived from nitrifying bacteria in autotrophic nitrifying biofilms

    OpenAIRE

    Okabe, Satoshi; Kindaichi, Tomonori; Ito, Tsukasa

    2005-01-01

    The cross-feeding of microbial products derived from 14C-labeled nitrifying bacteria to heterotrophic bacteria coexisting in an autotrophic nitrifying biofilm was quantitatively analyzed by using microautoradiography combined with fluorescence in situ hybridization (MAR-FISH). After only nitrifying bacteria were labeled with [14C] bicarbonate, biofilm samples were incubated with and without NH4+ as a sole energy source for 10 days. The transfer of 14C originally incorporated into nitrifying b...

  5. The abundance and diversity of ammonia-oxidizing bacteria in activated sludge under autotrophic domestication.

    Science.gov (United States)

    Li, Qiang; Ma, Chao; Sun, Shifang; Xie, Hui; Zhang, Wei; Feng, Jun; Song, Cunjiang

    2013-04-01

    Ammonia-oxidizing bacteria (AOB) play a key role in nitrogen-removal wastewater treatment plants (WWTPs) as they can transform ammonia into nitrite. AOB can be enriched in activated sludge through autotrophic domestication although they are difficult to be isolated. In this study, autotrophic domestication was carried out in a lab-scale sequencing-batch-reactor (SBR) system with two activated sludge samples. The ammonia removal capacity of the sludge samples increased during the domestication, and pH exhibited a negative correlation with the ammonia removal amount, which indicated that it was one important factor of microbial ammonia oxidation. The count of AOB, measured by the most probable number (MPN) method, increased significantly during autotrophic domestication as ammonia oxidation efficiency was enhanced. We investigated the changes in the community structure of AOB before and after domestication by amoA clone library and T-RFLP profile. It showed that AOB had been successfully enriched and the community structure significantly shifted during the domestication. Two groups of AOB were found in sludge samples: Nitrosomonas-like group remained predominant all the time and Nitrosospira-like group changed obviously. Simultaneously, the total heterotrophic bacteria were investigated by MPN and Biolog assay. The metabolic diversity of heterotrophs had changed minutely, although the count of them decreased significantly and lost superiority of microbial communities in the sludge. PMID:24620598

  6. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Science.gov (United States)

    Veuger, B.; Pitcher, A.; Schouten, S.; Sinninghe Damsté, J. S.; Middelburg, J. J.

    2013-03-01

    Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC (dissolved inorganic carbon) in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) in combination with compound-specific stable isotope (13C) analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41-221 nmol N L-1 h-1). Ammonium assimilation was always substantially lower than nitrification - with nitrification on average contributing 89% (range 73-97%) to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27-95 %). The inhibitor-sensitive 13C-PLFA (phospholipid-derived fatty acid) pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase)). These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance measurements only, in order to

  7. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Directory of Open Access Journals (Sweden)

    B. Veuger

    2013-03-01

    Full Text Available Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC (dissolved inorganic carbon in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate in combination with compound-specific stable isotope (13C analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N L−1 h−1. Ammonium assimilation was always substantially lower than nitrification – with nitrification on average contributing 89% (range 73–97% to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95 %. The inhibitor-sensitive 13C-PLFA (phospholipid-derived fatty acid pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance

  8. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Directory of Open Access Journals (Sweden)

    B. Veuger

    2012-11-01

    Full Text Available Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate in combination with compound-specific stable isotope (13C analysis of bacterial- and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N l−1h−1. Ammonium assimilation was always substantially lower than nitrification with nitrification on average contributing 89% (range 73–97% to total ammonium consumption.

    13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95%. The inhibitor-sensitive 13C-PLFA pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. Cell-specific 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance

  9. Autotrophic and heterotrophic denitrification for simultaneous removal of nitrogen, sulfur and organic matter.

    Science.gov (United States)

    Guerrero, Lorna; Aguirre, Juan P; Muñoz, Maria A; Barahona, Andrea; Huiliñir, Cesar; Montalvo, Silvio; Borja, Rafael

    2016-07-01

    The aim of this investigation was to assess the startup and operation of a laboratory-scale hybrid UASB-Anaerobic Filter Reactor (UASFB) of 1 L volume, kept at 30°C, in order to carry out a simultaneous autotrophic and heterotrophic denitrification process. First, the heterotrophic and autotrophic populations were separately enriched, with specific cultures and subsequently the UASFB was inoculated with 2 g L(-1) of volatile suspended solids (VSS), with a ratio of 1.5:1 (autotrophs: heterotrophs). The influent or synthetic wastewater used was composed of: Na2S2O3·5H2O, CH3COOK, NaNO3, NaHCO3, K2HPO4, NH4Cl and saline solution. The concentrations varied depending on the organic loading rate (OLR), nitrogen loading rate (NLR) and sulfur loading rate (SLR) applied. In the UASFB reactor, two experimental conditions were tested and assessed: (i) COD/N ratio of 3.6 and SLR of 0.75 kg S m(-3) d(-1); and (ii) COD/N ratio of 5.8 and SLR of 0.25 kg S m(-3) d(-1). The results obtained demonstrated that an inoculum coming from an anaerobic reactor was able to carry out the process, obtaining a maximum nitrate removal of 85.3% in the first stage of operation and 99.5% in the second stage. The recovery of sulfur in form of sulfate in the effluent did not present a tendency to stabilize during the measured time, with a maximum thiosulfate removal of 32.5%, when the SLR was lowered to 0.25 kg S m(-3) d(-1). The maximum organic matter elimination, measured as COD, was 75.8%, which indicates the relatively good performance and behavior of the heterotrophic microorganisms. PMID:27093220

  10. Enhanced start-up of anaerobic facultatively autotrophic biocathodes in bioelectrochemical systems

    KAUST Repository

    Zaybak, Zehra

    2013-12-01

    Biocathodes in bioelectrochemical systems (BESs) can be used to convert CO2 into diverse organic compounds through a process called microbial electrosynthesis. Unfortunately, start-up of anaerobic biocathodes in BESs is a difficult and time consuming process. Here, a pre-enrichment method was developed to improve start-up of anaerobic facultatively autotrophic biocathodes capable of using cathodes as the electron donor (electrotrophs) and CO2 as the electron acceptor. Anaerobic enrichment of bacteria from freshwater bog sediment samples was first performed in batch cultures fed with glucose and then used to inoculate BES cathode chambers set at -0.4V (versus a standard hydrogen electrode; SHE). After two weeks of heterotrophic operation of BESs, CO2 was provided as the sole electron acceptor and carbon source. Consumption of electrons from cathodes increased gradually and was sustained for about two months in concert with a significant decrease in cathode chamber headspace CO2. The maximum current density consumed was -34±4mA/m2. Biosynthesis resulted in organic compounds that included butanol, ethanol, acetate, propionate, butyrate, and hydrogen gas. Bacterial community analyses based on 16S rRNA gene clone libraries revealed Trichococcus palustris DSM 9172 (99% sequence identity) as the prevailing species in biocathode communities, followed by Oscillibacter sp. and Clostridium sp. Isolates from autotrophic cultivation were most closely related to Clostridium propionicum (99% sequence identity; ZZ16), Clostridium celerecrescens (98-99%; ZZ22, ZZ23), Desulfotomaculum sp. (97%; ZZ21), and Tissierella sp. (98%; ZZ25). This pre-enrichment procedure enables simplified start-up of anaerobic biocathodes for applications such as electrofuel production by facultatively autotrophic electrotrophs. © 2013 Elsevier B.V.

  11. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor

    International Nuclear Information System (INIS)

    Highlights: → Intensified biofilm-electrode reactor using cooperative denitrification is developed. → IBER combines heterotrophic and autotrophic denitrification. → CO2 formed by heterotrophic denitrification is used by autotrophic bacteria. → Optimum running conditions are C/N = 0.75, HRT = 8 h, and I = 40 mA. → A novel degradation mechanism for cooperating denitrification process is proposed. - Abstract: An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO3-N50 mg L-1) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8 h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO3-N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO2 produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate.

  12. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yingxin [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan); Feng, Chuanping, E-mail: fengchuangping@gmail.com [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Wang, Qinghong; Yang, Yingnan; Zhang, Zhenya; Sugiura, Norio [Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan)

    2011-09-15

    Highlights: {yields} Intensified biofilm-electrode reactor using cooperative denitrification is developed. {yields} IBER combines heterotrophic and autotrophic denitrification. {yields} CO{sub 2} formed by heterotrophic denitrification is used by autotrophic bacteria. {yields} Optimum running conditions are C/N = 0.75, HRT = 8 h, and I = 40 mA. {yields} A novel degradation mechanism for cooperating denitrification process is proposed. - Abstract: An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO{sub 3}{sup -}N50 mg L{sup -1}) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8 h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO{sub 3}{sup -}N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO{sub 2} produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate.

  13. Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

    Directory of Open Access Journals (Sweden)

    W. Koeve

    2010-08-01

    Full Text Available The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (ΔCO2:ΔN2, varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of ΔCO2:ΔN2 can be found. However, accounting for concomitant diffusive fluxes of CO2, the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic

  14. Redox stratified biofilms to support completely autotrophic nitrogen removal: Principles and results

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Smets, Barth F.

    biofilm structure with aerobic ammonium oxidizing bacteria dominating the areas of the biofilm closer to the membrane surface while anaerobic oxidizing bacteria populated mainly the outer biofilm region. The biofilm was approximately 500 m thick and featured both aerobic and anaerobic ammonium oxidizing...... the outgrowth of nitrite oxidizing bacteria communities. Autotrophic nitrogen removal is already revealing itself as a cheap alternative to treat concentrated nitrogen streams. However, we believe that this concept can be taken a step further in MABRs and become an even more cost-effective, compact...

  15. Performance of an autotrophic nitrogen removing reactor: Diagnosis through fuzzy logic

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Mutlu, Ayten Gizem; Gernaey, Krist; Smets, Barth F.; Sin, Gürkan

    Autotrophic nitrogen removal through nitritation-anammox in one stage SBRs is an energy and cost efficient alternative to conventional treatment methods. Intensification of an already complex biological system challenges our ability to observe, understand, diagnose, and control the system. A fuzzy...... logic diagnosis tool was developed, utilizing stoichiometric and concentration ratio measurements and removal efficiencies, along with rules derived from process knowledge. The tool could accurately determine the overall performance of the system and can therefore serve as a powerful tool to provide...

  16. The sulfocyanic theory on the origin of life: towards a critical reappraisal of an autotrophic theory

    Science.gov (United States)

    Perezgasga, L.; Silva, E.; Lazcano, A.; Negrin-Mendoza, A.

    2003-10-01

    In the early 1930s, Alfonso L. Herrera proposed his so-called sulfocyanic theory on the origin of life, an autotrophic proposal on the first living beings according to which NH4SCN and H2CO acted as raw materials for the synthesis of bio-organic compounds inside primordial photosynthetic protoplasmic structures. Although the work of Herrera is frequently cited in historical analysis of the development of the origin of life studies, very little attention has been given to the chemical significance of the reactions he published. In this paper we report the results of our search for amino acids obtained from a reactive mixture used by Herrera from 1933 onwards. Chromatograms using the high-pressure liquid chromatography (HPLC) technique suggest the presence of several amino acids, the total yield being 2% of the initial thiocyanate used. Preliminary identification based on HPLC retention times suggests the presence of glycine, alanine, cysteine and methionine. Alanine was the most abundant amino acid in all samples of fractionated material analysed. Although the starting materials used by Herrera were determined by his autotrophic hypothesis on the origin of cells, our results show that his experiments may provide insights into the abiotic synthesis of sulfur-containing amino acids within the framework of a heterotrophic emergence of life.

  17. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions.

    Science.gov (United States)

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ(15)NNO3), carbon in dissolved inorganic carbon (δ(13)CDIC), and sulfur in sulfate (δ(34)SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ(13)CDIC (from -7.7‰ to -12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was -4.7‰), suggesting the contribution of C of trisodium citrate (δ(13)C=-12.4‰). No SO4(2-) and δ(34)SSO4 changes were observed. In the AD experiment, clear fractionation of δ(13)CDIC during DIC consumption (εC=-7.8‰) and δ(34)SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN=-12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field. PMID:26529303

  18. High CO2 subsurface environment enriches for novel microbial lineages capable of autotrophic carbon fixation

    Science.gov (United States)

    Probst, A. J.; Jerett, J.; Castelle, C. J.; Thomas, B. C.; Sharon, I.; Brown, C. T.; Anantharaman, K.; Emerson, J. B.; Hernsdorf, A. W.; Amano, Y.; Suzuki, Y.; Tringe, S. G.; Woyke, T.; Banfield, J. F.

    2015-12-01

    Subsurface environments span the planet but remain little understood from the perspective of the capacity of the resident organisms to fix CO2. Here we investigated the autotrophic capacity of microbial communities in range of a high-CO2 subsurface environments via analysis of 250 near-complete microbial genomes (151 of them from distinct species) that represent the most abundant organisms over a subsurface depth transect. More than one third of the genomes belonged to the so-called candidate phyla radiation (CPR), which have limited metabolic capabilities. Approximately 30% of the community members are autotrophs that comprise 70% of the microbiome with metabolism likely supported by sulfur and nitrogen respiration. Of the carbon fixation pathways, the Calvin Benson Basham Cycle was most common, but the Wood-Ljungdhal pathway was present in the greatest phylogenetic diversity of organisms. Unexpectedly, one organism from a novel phylum sibling to the CPR is predicted to fix carbon by the reverse TCA cycle. The genome of the most abundant organism, an archaeon designated "Candidatus Altiarchaeum hamiconexum", was also found in subsurface samples from other continents including Europe and Asia. The archaeon was proven to be a carbon fixer using a novel reductive acetyl-CoA pathway. These results provide evidence that carbon dioxide is the major carbon source in these environments and suggest that autotrophy in the subsurface represents a substantial carbon dioxide sink affecting the global carbon cycle.

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

    Directory of Open Access Journals (Sweden)

    Pongsak (Lek Noophan

    2008-07-01

    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.

  20. The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage.

    Science.gov (United States)

    Ma, Bin; Zhang, Shujun; Zhang, Liang; Yi, Peng; Wang, Junmin; Wang, Shuying; Peng, Yongzhen

    2011-09-01

    The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage was examined in this study. The obtained results showed that total nitrogen (TN) could be efficiently removed by 88.38% when influent TN and chemical oxygen demand (COD) were 45.87 and 44.40 mg/L, respectively. In the first stage, nitritation was instantly achieved by the bioaugmentation strategy, and can be maintained under limited oxygen condition (below 0.2mg/L). The ratio of nitrite to ammonium in the effluent of the nitritation reactor can be controlled at approximate 1.0 by adjusting aeration rate. In the second stage, anammox was realized in the upflow anaerobic sludge blanket (UASB) reactor, where the total nitrogen removal rate was 0.40 kg Nm(-3)d(-1) under limited-substrate condition. Therefore, the organic matter in sewage can be firstly concentrated in biomass which could generate biogas (energy). Then, nitrogen in sewage could be removed in a two-stage autotrophic nitrogen removal process. PMID:21719278

  1. Particulate Pyrite Autotrophic Denitrification (PPAD) for Remediation of Nitrate-contaminated Groundwater

    Science.gov (United States)

    Tong, S.; Rodriguez-Gonzalez, L. C.; Henderson, M.; Feng, C.; Ergas, S. J.

    2015-12-01

    The rapid movement of human civilization towards urbanization, industrialization, and increased agricultural activities has introduced a large amount of nitrate into groundwater. Nitrate is a toxic substance discharged from groundwater to rivers and leads to decreased dissolved oxygen and eutrophication. For this experiment, an electron donor is needed to convert nitrate into non-toxic nitrogen gas. Pyrite is one of the most abundant minerals in the earth's crust making it an ideal candidate as an electron donor. The overall goal of this research was to investigate the potential for pyrite to be utilized as an electron donor for autotrophic denitrification of nitrate-contaminated groundwater. Batch studies of particulate pyrite autotrophic denitrification (PPAD) of synthetic groundwater (100 mg NO3--N L-1) were set up with varying biomass concentration, pyrite dose, and pyrite particle size. Reactors were seeded with mixed liquor volatile suspended solids (VSS) from a biological nitrogen removal wastewater treatment facility. PPAD using small pyrite particles (treatment and promoted the utilization of pyrite in the field of environmental remediation.

  2. Bio-electrochemical synthesis of commodity chemicals by autotrophic acetogens utilizing CO_{2} for environmental remediation

    Indian Academy of Sciences (India)

    GUGAN JABEEN; ROBINA FAROOQ

    2016-09-01

    Bio-electrochemical synthesis (BES) is a technique in which electro-autotrophic bacteria such as Clostridiumljungdahlii utilize electric currents as an electron source from the cathode to reduce CO_{2} to extracellular, multicarbon,exquisite products through autotrophic conversion. The BES of volatile fatty acids and alcohols directly fromCO_{2} is a sustainable alternative for non-renewable, petroleum-based polymer production. This conversion ofCO_{2} implies reduction of greenhouse gas emissions. The synthesis of heptanoic acid, heptanol, hexanoic acidand hexanol, for the first time, by Clostridium ljungdahlii was a remarkable achievement of BES. In ourstudy, these microorganisms were cultivated on the cathode of a bio-electrochemical cell at −400 mV by aDC power supply at 37°C, pH 6.8, and was studied for both batch and continuous systems. Pre-enrichment ofbio-cathode enhanced the electroactivity of cells and resulted in maximizing extracellular products in lesstime. The main aim of the research was to investigate the impact of low-cost substrate CO_{2}, and the longercathode recovery range was due to bacterial reduction of CO_{2} to multicarbon chemical commodities withelectrons driven from the cathode. Reactor design was simplified for cost-effectiveness and to enhance energyefficiencies. The Columbic recovery of ethanoic acid, ethanol, ethyl butyrate, hexanoic acid, heptanoic acidand hexanol being in excess of 80% proved that BES was a remarkable technology.

  3. Bio-electrochemical synthesis of commodity chemicals by autotrophic acetogens utilizing CO2 for environmental remediation.

    Science.gov (United States)

    Jabeen, Gugan; Farooq, Robina

    2016-09-01

    Bio-electrochemical synthesis (BES) is a technique in which electro-autotrophic bacteria such as Clostridium ljungdahlii utilize electric currents as an electron source from the cathode to reduce CO2 to extracellular, multicarbon, exquisite products through autotrophic conversion. The BES of volatile fatty acids and alcohols directly from CO2 is a sustainable alternative for non-renewable, petroleum-based polymer production. This conversion of CO2 implies reduction of greenhouse gas emissions. The synthesis of heptanoic acid, heptanol, hexanoic acid and hexanol, for the first time, by Clostridium ljungdahlii was a remarkable achievement of BES. In our study, these microorganisms were cultivated on the cathode of a bio-electrochemical cell at -400 mV by a DC power supply at 37 degree Centrigrade, pH 6.8, and was studied for both batch and continuous systems. Pre-enrichment of bio-cathode enhanced the electroactivity of cells and resulted in maximizing extracellular products in less time. The main aim of the research was to investigate the impact of low-cost substrate CO2, and the longer cathode recovery range was due to bacterial reduction of CO2 to multicarbon chemical commodities with electrons driven from the cathode. Reactor design was simplified for cost-effectiveness and to enhance energy efficiencies. The Columbic recovery of ethanoic acid, ethanol, ethyl butyrate, hexanoic acid, heptanoic acid and hexanol being in excess of 80 percent proved that BES was a remarkable technology. PMID:27581929

  4. Heterotrophic and Autotrophic Microbial Populations in Cold Perennial Springs of the High Arctic ▿ †

    Science.gov (United States)

    Perreault, Nancy N.; Greer, Charles W.; Andersen, Dale T.; Tille, Stefanie; Lacrampe-Couloume, Georges; Lollar, Barbara Sherwood; Whyte, Lyle G.

    2008-01-01

    The saline springs of Gypsum Hill in the Canadian high Arctic are a rare example of cold springs originating from deep groundwater and rising to the surface through thick permafrost. The heterotrophic bacteria and autotrophic sulfur-oxidizing bacteria (up to 40% of the total microbial community) isolated from the spring waters and sediments were classified into four phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) based on 16S rRNA gene analysis; heterotrophic isolates were primarily psychrotolerant, salt-tolerant, facultative anaerobes. Some of the isolates contained genes for thiosulfate oxidation (soxB) and anoxygenic photosynthesis (pufM), possibly enabling the strains to better compete in these sulfur-rich environments subject to long periods of illumination in the Arctic summer. Although leucine uptake by the spring water microbial community was low, CO2 uptake was relatively high under dark incubation, reinforcing the idea that primary production by chemoautotrophs is an important process in the springs. The small amounts of hydrocarbons in gases exsolving from the springs (0.38 to 0.51% CH4) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy. Anaerobic heterotrophic sulfur oxidation and aerobic autotrophic sulfur oxidation activities were demonstrated in sediment slurries. Overall, our results describe an active microbial community capable of sustainability in an extreme environment that experiences prolonged periods of continuous light or darkness, low temperatures, and moderate salinity, where life seems to rely on chemolithoautotrophy. PMID:18805995

  5. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions

    Science.gov (United States)

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ15NNO3), carbon in dissolved inorganic carbon (δ13CDIC), and sulfur in sulfate (δ34SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ13CDIC (from - 7.7‰ to - 12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was - 4.7‰), suggesting the contribution of C of trisodium citrate (δ13C = - 12.4‰). No SO42 - and δ34SSO4 changes were observed. In the AD experiment, clear fractionation of δ13CDIC during DIC consumption (εC = - 7.8‰) and δ34SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN = - 12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field.

  6. Sulfide removal by simultaneous autotrophic and heterotrophic desulfurization-denitrification process

    International Nuclear Information System (INIS)

    An anaerobic attached-growth bioreactor (AAGBR) of 3.52 L was operated for 510 days to treat sulfide-laden organic wastewater where nitrate and nitrite were introduced as electron acceptors. When the influent sulfide was kept at 200 mg S2--S/L and organic carbon was increased from 20 to 33.6 mg C/L, and the hydraulic retention time decreased from 41.4 to 2.67 h, the removal rates of sulfide and organic carbon reached 99.9% and 91.8% at the loading rates of 1800 mg S2--S/(L d) and 302.4 mg C/(L d), respectively. Simultaneously, the introduced electron acceptors of nitrate and nitrite were, respectively, removed by 99.9% and 99.9% at the loading rates of 472.5 mg NO3--N/(L d) and 180 mg NO2--N/(L d). Inside the AAGBR, both autotrophic and heterotrophic denitrification processes were noted to take place. When the influent organic carbon was increased from 20 to 33.6 mg C/L, the nitrate and nitrite consumed for heterotrophic denitrification accounted for 27.3% and 48.5%, respectively. This simultaneous autotrophic and heterotrophic desulfurization-denitrification process has provided a demonstration of the possibility to eliminate sulfide and organic carbon with the presence of nitrate and nitrite

  7. An operation protocol for facilitating start-up of single-stage autotrophic nitrogen removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan; Smets, Barth F.

    2012-01-01

    Start-up and operation of single-stage nitritation/anammox reactor employing complete autotrophic nitrogen can be difficult. Keeping the performance criteria and monitoring the microbial community composition may not be easy or fast enough to take action on time. In this study, a control strategy...

  8. Coniochaeta ligniaria: antifungal activity of the cryptic endophytic fungus associated with autotrophic cultures of the medicinal plant Smallanthus sonchifolius (Asteraceae)

    Science.gov (United States)

    Few studies have addressed the presence and bioactivity of endophytic fungi living in plantlets growing under in vitro conditions. We isolated a fungus UM 109 from autotrophic cultures of the medicinal plant Smallanthus sonchifolius (yacon). The species was identified as Coniochaeta ligniaria using ...

  9. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems.

    Science.gov (United States)

    Hicks Pries, Caitlin E; van Logtestijn, Richard S P; Schuur, Edward A G; Natali, Susan M; Cornelissen, Johannes H C; Aerts, Rien; Dorrepaal, Ellen

    2015-12-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change feedback. Few studies partitioning ecosystem respiration examine decadal warming effects or compare responses among ecosystems. Here, we first examined how 11 years of warming during different seasons affected autotrophic and heterotrophic respiration in a bryophyte-dominated peatland in Abisko, Sweden. We used natural abundance radiocarbon to partition ecosystem respiration into autotrophic respiration, associated with production, and heterotrophic decomposition. Summertime warming decreased the age of carbon respired by the ecosystem due to increased proportional contributions from autotrophic and young soil respiration and decreased proportional contributions from old soil. Summertime warming's large effect was due to not only warmer air temperatures during the growing season, but also to warmer deep soils year-round. Second, we compared ecosystem respiration responses between two contrasting ecosystems, the Abisko peatland and a tussock-dominated tundra in Healy, Alaska. Each ecosystem had two different timescales of warming (permafrost ecosystems. PMID:26150277

  10. Cross effect of temperature, pH and free ammonia on autotrophic denitrification process with sulphide as electron donor.

    Science.gov (United States)

    Fajardo, Carmen; Mora, Mabel; Fernández, Isaac; Mosquera-Corral, Anuska; Campos, José Luis; Méndez, Ramón

    2014-02-01

    Autotrophic denitrification is a suitable technology to simultaneously remove oxidised nitrogen compounds and reduced sulphur compounds yielding nitrogen gas, sulphur and sulphate as the main products. In this work, several batch tests were conducted to investigate the cross effect of temperature, pH and free ammonia on the autotrophic denitrification. Denitrification efficiencies above 95% were achieved at 35°C and pH 7.5-8.0 with maximum specific autotrophic denitrifying activities up to 188mgN2g(-1)VSSd(-1). Free ammonia did not show any effect on denitrification at concentrations up to 53mg NH3-NL(-1). Different sulphide concentrations were also tested with stoichiometric nitrite and nitrate concentrations. Sulphide inhibited denitrification at concentrations higher than 200mgS(2-)L(-1). A 50% inhibition was also found at nitrite concentrations above 48mg NO2(-)-NL(-1). The maximum specific activity decreased until a value of 25mgN2g(-1) VSSd(-1) at 232mg NO2(-)-NL(-1). The Haldane model was used to describe denitrification inhibition caused by nitrite. Kinetic parameters determined from the fitting of experimental data were rmax=176mgN2g(-1)VSSd(-1), Ks=10.7mg NO2(-)-NL(-1) and Ki=34.7mg NO2(-)-NL(-1). The obtained model allowed optimising an autotrophic denitrification process by avoiding situations of inhibition and thus obtaining higher denitrification efficiencies. PMID:24216266

  11. Autotrophic and heterotrophic activity in Arctic first-year sea-ice: Seasonal study from Marlene Bight, SW Greenland

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Kristensen, Morten; Rysgaard, Søren;

    2010-01-01

    We present a study of autotrophic and heterotrophic activities of Arctic sea ice (Malene Bight, SW Greenland) as measured by 2 different approaches: (1) standard incubation techniques ((HCO3-)-C-14 and [H-3] thymidine incubation) on sea ice cores brought to the laboratory and (2) cores incubated ...

  12. Selection of controlled variables in bioprocesses. Application to a SHARON-Anammox process for autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Valverde Perez, Borja; Sin, Gürkan

    Selecting the right controlled variables in a bioprocess is challenging since the objectives of the process (yields, product or substrate concentration) are difficult to relate with a given actuator. We apply here process control tools that can be used to assist in the selection of controlled...... variables to the case of the SHARON-Anammox process for autotrophic nitrogen removal....

  13. Development of novel control strategies for single-stage autotrophic nitrogen removal: A process oriented approach

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Gernaey, Krist;

    2014-01-01

    The autotrophic nitrogen removing granular sludge process is a novel and intensified process. However, its stable operation and control remain a challenging issue. In this contribution, a process oriented approach was used to develop, evaluate and benchmark novel control strategies to ensure stable...... operation and rejection of disturbances. Three novel control strategies were developed, evaluated, and benchmarked against each other: a feedforward control (control structure 1 – CS#1), a rule-based feedback control (CS#2), and a feedforward–feedback controller, in which the feedback loop updates the set...... satisfactorily. Thus, the appropriate design will depend on the specific disturbances in the influent generated in the upstream units of the wastewater treatment plant....

  14. Biodegradation of tetramethylammonium hydroxide (TMAH) in completely autotrophic nitrogen removal over nitrite (CANON) process.

    Science.gov (United States)

    Chen, Shen-Yi; Lu, Li-An; Lin, Jih-Gaw

    2016-06-01

    This study conducted a completely autotrophic nitrogen removal over nitrite (CANON) process in a continuous anoxic upflow bioreactor to treat synthetic wastewater with TMAH (tetramethylammonium hydroxide) ranging from 200 to 1000mg/L. The intermediates were analyzed for understanding the metabolic pathway of TMAH biodegradation in CANON process. In addition, (15)N-labeled TMAH was used as the substrate in a batch anoxic bioreactor to confirm that TMAH was converted to nitrogen gas in CANON process. The results indicated that TMAH was almost completely biodegraded in CANON system at different influent TMAH concentrations of 200, 500, and 1000mg/L. The average removal efficiencies of total nitrogen were higher than 90% during the experiments. Trimethylamine (TMA) and methylamine (MA) were found to be the main biodegradation intermediates of TMAH in CANON process. The production of nitrogen gas with (15)N-labeled during the batch anaerobic bioreactor indicated that CANON process successfully converted TMAH into nitrogen gas. PMID:26879202

  15. Microbial community stratification in Membrane-Aerated Biofilm Reactors for Completely Autotrophic Nitrogen Removal

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Ruscalleda, Maël; Terada, Akihiko;

    bacterial granules or biofilms. In this sense, completely autotrophic nitrogen removal from high ammonium strength wastewater was achieved in a Membrane-Aereated Biofilm Reactor (MABR) in a single step. Here, a biofilm containing nitrifiers (Aerobic Ammonium and Nitrite Oxidizing Bacteria, AOB and NOB......Due to the necessity of a source of nitrite, most of the processes involving Anaerobic Ammonium Oxidation (Anammox) are based on a separated two-step process with a previous partial-nitritation reactor. However, these two processes can occur simultaneously in the same reactor by taking advantage of......, respectively) and Anaerobic Ammonium Oxidizing Bacteria (AnAOB) is grown on bubbleless aeration membranes to remove ammonium. Since oxygen permeates through the membrane-biofilm interface while ammonium diffuses into the biofilm from the biofilm-liquid interface, oxygen gradients can be established across the...

  16. Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

    DEFF Research Database (Denmark)

    Gilmore, Kevin R.; Terada, Akihiko; Smets, Barth F.;

    2013-01-01

    allowed anaerobic ammonium-oxidizing bacteria (AnaerAOB) to develop and be retained for > 250 days. Daily autotrophic nitrogen removal of 1.7 g N/m(2) (75% of influent N load) was achieved at an oxygen/nitrogen surface loading ratio of 2.2, with up to 85% of the influent N proceeding through Anaer......AOB. During early nitritation, nitrogen oxide (NO(g), NO2(g), and N2O(g)) emissions comprised up to 10% of the removed influent nitrogen, but emissions disappeared after proliferation of AnaerAOB. Microbial communities were radially stratified, with aerobic ammonium-oxidizing bacteria (AerAOB) colonizing...... elimination of gaseous nitrogen oxide emissions....

  17. A novel control strategy for single-stage autotrophic nitrogen removal in SBR

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist; Smets, Barth F.; Sin, Gürkan

    2015-01-01

    A novel feedforward–feedback control strategy was developed for complete autotrophic nitrogen removal in a sequencing batch reactor. The aim of the control system was to carry out the regulation of the process while keeping the system close to the optimal operation. The controller was designed...... based on a process model and then tested experimentally. The resulting batch-to-batch control strategy had the total nitrogen removal efficiency as controlled variable and the setting of the aeration mass flow controller as manipulated variable. Compared to manual operation mode (constant air supply...... lab-scale reactor is a promising result, which brings this control strategy one step closer to full-scale implementation....

  18. Membrane biofouling in a wastewater nitrification reactor: microbial succession from autotrophic colonization to heterotrophic domination

    KAUST Repository

    Lu, Huijie

    2015-10-22

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles.

  19. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars

    Directory of Open Access Journals (Sweden)

    Viktoria Shcherbakova

    2015-09-01

    Full Text Available The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2T M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth’s subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  20. Residence time of carbon substrate for autotrophic respiration of a grassland ecosystem correlates with the carbohydrate status of its vegetation

    Science.gov (United States)

    Ostler, Ulrike; Lehmeier, Christoph A.; Schleip, Inga; Schnyder, Hans

    2016-04-01

    Ecosystem respiration is composed of two component fluxes: (1) autotrophic respiration, which comprises respiratory activity of plants and plant-associated microbes that feed on products of recent photosynthetic activity and (2) heterotrophic respiration of microbes that decompose organic matter. The mechanistic link between the availability of carbon (C) substrate for ecosystem respiration and its respiratory activity is not well understood, particularly in grasslands. Here, we explore, how the kinetic features of the supply system feeding autotrophic ecosystem respiration in a temperate humid pasture are related to the content of water-soluble carbohydrates and remobilizable protein (as potential respiratory substrates) in vegetation biomass. During each September 2006, May 2007 and September 2007, we continuously labeled 0.8 m2 pasture plots with 13CO2/12CO2 and observed ecosystem respiration and its tracer content every night during the 14-16 day long labeling periods. We analyzed the tracer kinetics with a pool model, which allowed us to precisely partition ecosystem respiration into its autotrophic and heterotrophic flux components. At the end of a labeling campaign, we harvested aboveground and belowground plant biomass and analyzed its non-structural C contents. Approximately half of ecosystem respiration did not release any significant amount of tracer during the labeling period and was hence characterized as heterotrophic. The other half of ecosystem respiration was autotrophic, with a mean residence time of C in the respiratory substrate pool between 2 and 6 d. Both the rate of autotrophic respiration and the turnover of its substrate supply pool were correlated with plant carbohydrate content, but not with plant protein content. These findings are in agreement with studies in controlled environments that revealed water-soluble carbohydrates as the main substrate and proteins as a marginal substrate for plant respiration under favorable growth conditions

  1. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    Science.gov (United States)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  2. Targeting Autotrophic and Lithotrophic Microorganisms from Fumarolic Ice Caves of Mt. Erebus, Antarctica

    Science.gov (United States)

    Anitori, R.; Davis, R.; Connell, L.; Kelley, M.; Staudigel, H.; Tebo, B. M.

    2011-12-01

    Terrestrial and aquatic volcanic oligotrophic environments can host microorganisms that obtain their energy from reduced inorganic chemicals present in volcanic rocks and soils. We sampled basaltic rock from terrestrial Dark Oligotrophic Volcanic Ecosystems (DOVEs) located in two fumarole ice caves, Warren and Warren West, located near the summit of Mt. Erebus, Antarctica. For reference, we sampled a similar cave, Harry's Dream, which receives continuous light during the Austral summer. We report here culturing data for bacterial and eukaryotic microbes from rocky soils in these caves when targeting lithotrophic organisms using media containing reduced inorganic compounds (Mn2+, Fe2+, NH4+). In addition, to test for the possible presence of inorganic carbon fixation, we screened samples for the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) gene. Culturing of soil samples on media targeting both autotrophs and heterotrophs yielded a diverse collection of generally slow-growing colonies of bacteria (majority), fungi and non-fungal eukaryotes. Manganese(II)-oxidizing colonies were identified in Warren and Harry's Dream, and these exhibited two colony morphotypes upon subculturing. Sequencing of the PCR amplified 16S rRNA gene identified a bacterium distantly related to Pseudonocardia sp., a genus with known manganese oxidizers. Other bacteria enriched included members of the Actinobacteria, Alphaproteobacteria and Betaproteobacteria. There was a low diversity in cultured eukaryotes representing several potential undescribed species (Geomyces sp., Penicillium sp.) and isolates that may represent alternate, previously undescribed habitats and forms (Psilolechia leprosa, Alternaria alternata). One Warren isolate was a 99% 16S rRNA match to the N2 fixer Bradyrhizobium sp.; when inoculated into liquid medium specific for N2 fixers, growth was maintained upon subculture. Putative iron oxidizers were also enriched from the two DOVE caves, using slush agar iron

  3. Sequential Aeration of Membrane-Aerated Biofilm Reactors for High-Rate Autotrophic Nitrogen Removal: Experimental Demonstration

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Sun, Sheng-Peng; Lackner, Susanne;

    2010-01-01

    One-stage autotrophic nitrogen (N) removal, requiring the simultaneous activity of aerobic and anaerobic ammonium oxidizing bacteria (AOB and AnAOB), can be obtained in spatially redox-stratified biofilms. However, previous experience with Membrane-Aerated Biofilm Reactors (MABRs) has revealed a...... difficulty in reducing the abundance and activity of nitrite oxidizing bacteria (NOB), which drastically lowers process efficiency. Here we show how sequential aeration is an effective strategy to attain autotrophic N removal in MABRs: Two separate MABRs, which displayed limited or no N removal under......S rRNA gene confirmed that sequential aeration, even at elevated average O2 loads, stimulated the abundance of AnAOB and AOB and prevented the increase in NOB. Nitrous oxide (N2O) emissions were 100-fold lower compared to other anaerobic ammonium oxidation (Anammox)-nitritation systems. Hence, by...

  4. Thaumarchaeotes abundant in refinery nitrifying sludges express amoA but are not obligate autotrophic ammonia oxidizers

    OpenAIRE

    Mußmann, M; Brito, I.; A. Pitcher; Hatzenpichler, R.; Richter, A; Nielsen, J. L.; Nielsen, P. H.; Daims, H.; MÜller, A.; Wagner, M.; Head, I.M.

    2011-01-01

    Nitrification is a core process in the global nitrogen cycle that is essential for the functioning of many ecosystems. The discovery of autotrophic ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota has changed our perception of the microbiology of nitrification, in particular since their numerical dominance over ammonia-oxidizing bacteria (AOB) in many environments has been revealed. These and other data have led to a widely held assumption that all amoA-encoding members of the...

  5. Thaumarchaeotes abundant in refinery nitrifying sludges express amoA but are not obligate autotrophic ammonia oxidizers

    OpenAIRE

    Mußmann, Marc; Brito, Ivana; Pitcher, Angela; Sinninghe Damsté, Jaap S.; Hatzenpichler, Roland; Richter, Andreas; Nielsen, Jeppe L.; Nielsen, Per Halkjær; Müller, Anneliese; Daims, Holger; WAGNER, MICHAEL; Head, Ian M.

    2011-01-01

    Nitrification is a core process in the global nitrogen cycle that is essential for the functioning of many ecosystems. The discovery of autotrophic ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota has changed our perception of the microbiology of nitrification, in particular since their numerical dominance over ammonia-oxidizing bacteria (AOB) in many environments has been revealed. These and other data have led to a widely held assumption that all amoA-encoding members of the...

  6. Autotrophic, hydrogen-oxidizing, denitrifying bacteria in groundwater, potential agents for bioremediation of nitrate contamination

    Science.gov (United States)

    Smith, R.L.; Ceazan, M.L.; Brooks, M.H.

    1994-01-01

    Addition of hydrogen or formate significantly enhanced the rate of consumption of nitrate in slurried core samples obtained from an active zone of denitrification in a nitrate-contaminated sand and gravel aquifer (Cape Cod, Mass.). Hydrogen uptake by the core material was immediate and rapid, with an apparent K(m) of 0.45 to 0.60 ??M and a V(max) of 18.7 nmol cm-3 h-1 at 30??C. Nine strains of hydrogen-oxidizing denitrifying bacteria were subsequently isolated from the aquifer. Eight of the strains grew autotrophically on hydrogen with either oxygen or nitrate as the electron acceptor. One strain grew mixotrophically. All of the isolates were capable of heterotrophic growth, but none were similar to Paracoccus denitrificans, a well-characterized hydrogen-oxidizing denitrifier. The kinetics for hydrogen uptake during denitrification were determined for each isolate with substrate depletion progress curves; the K(m)s ranged from 0.30 to 3.32 ??M, with V(max)s of 1.85 to 13.29 fmol cell-1 h-1. Because these organisms appear to be common constituents of the in situ population of the aquifer, produce innocuous end products, and could be manipulated to sequentially consume oxygen and then nitrate when both were present, these results suggest that these organisms may have significant potential for in situ bioremediation of nitrate contamination in groundwater.

  7. Nitrate removal and microbial analysis by combined micro-electrolysis and autotrophic denitrification.

    Science.gov (United States)

    Xing, Wei; Li, Desheng; Li, Jinlong; Hu, Qianyi; Deng, Shihai

    2016-07-01

    A process combining micro-electrolysis and autotrophic denitrification (CEAD) with iron-carbon micro-electrolysis carriers was developed for nitrate removal. The process was performed using organic-free influent with a NO3(-)-N concentration of 40.0±3.0mg/L and provided an average nitrate removal efficiency of 95% in stable stages. The total nitrogen removal efficiency reached 75%, with 21% of NO3(-)-N converted into NH4(+)-N. The corresponding hydraulic retention time was 8-10h, and the optimal pH ranged from 8.5 to 9.5. Microbial analysis with high-throughput sequencing revealed that dominant microorganisms in the reactor belonged to the classes of β-, γ-, and α-Proteobacteria. The abundance of the genera Thermomonas significantly increased during the operation, comprising 21.4% and 24.1% in sludge attached to the carriers in the middle and at the bottom of the reactor, respectively. The developed CEAD achieved efficient nitrate removal from water without organics, which is suitable for practical application. PMID:27019127

  8. Investigating the association between photosynthetic efficiency and generation of biophotoelectricity in autotrophic microbial fuel cells

    Science.gov (United States)

    Ciniciato, Gustavo P. M. K.; Ng, Fong-Lee; Phang, Siew-Moi; Jaafar, Muhammad Musoddiq; Fisher, Adrian C.; Yunus, Kamran; Periasamy, Vengadesh

    2016-01-01

    Microbial fuel cells operating with autotrophic microorganisms are known as biophotovoltaic devices. It represents a great opportunity for environmentally-friendly power generation using the energy of the sunlight. The efficiency of electricity generation in this novel system is however low. This is partially reflected by the poor understanding of the bioelectrochemical mechanisms behind the electron transfer from these microorganisms to the electrode surface. In this work, we propose a combination of electrochemical and fluorescence techniques, giving emphasis to the pulse amplitude modulation fluorescence. The combination of these two techniques allow us to obtain information that can assist in understanding the electrical response obtained from the generation of electricity through the intrinsic properties related to the photosynthetic efficiency that can be obtained from the fluorescence emitted. These were achieved quantitatively by means of observed changes in four photosynthetic parameters with the bioanode generating electricity. These are the maximum quantum yield (Fv/Fm), alpha (α), light saturation coefficient (Ek) and maximum rate of electron transfer (rETRm). The relationship between the increases in the current density collected by the bioanode to the decrease of the rETRm values in the photosynthetic pathway for the two microorganisms was also discussed. PMID:27502051

  9. Startup and oxygen concentration effects in a continuous granular mixed flow autotrophic nitrogen removal reactor.

    Science.gov (United States)

    Varas, Rodrigo; Guzmán-Fierro, Víctor; Giustinianovich, Elisa; Behar, Jack; Fernández, Katherina; Roeckel, Marlene

    2015-08-01

    The startup and performance of the completely autotrophic nitrogen removal over nitrite (CANON) process was tested in a continuously fed granular bubble column reactor (BCR) with two different aeration strategies: controlling the oxygen volumetric flow and oxygen concentration. During the startup with the control of oxygen volumetric flow, the air volume was adjusted to 60mL/h and the CANON reactor had volumetric N loadings ranging from 7.35 to 100.90mgN/Ld with 36-71% total nitrogen removal and high instability. In the second stage, the reactor was operated at oxygen concentrations of 0.6, 0.4 and 0.2mg/L. The best condition was 0.2 mgO2/L with a total nitrogen removal of 75.36% with a CANON reactor activity of 0.1149gN/gVVSd and high stability. The feasibility and effectiveness of CANON processes with oxygen control was demonstrated, showing an alternative design tool for efficiently removing nitrogen species. PMID:25965951

  10. Effects of HRT and water temperature on nitrogen removal in autotrophic gravel filter.

    Science.gov (United States)

    Xu, Jing-Hang; He, Sheng-Bing; Wu, Su-Qing; Huang, Jung-Chen; Zhou, Wei-Li; Chen, Xue-Chu

    2016-03-01

    Organic Carbon added to low ratio of carbon to nitrogen (C/N ratio) wastewater to enhance heterotrophic denitrification performance might lead to higher operating costs and secondary pollution. In this study, sodium thiosulfate (Na2S2O3) was applied as an electron donor for a gravel filter (one kind of constructed wetland) to investigate effects of hydraulic retention time (HRT) and water temperature on the nitrate removal efficiency. The results show that with an HRT of 12 h, the average total nitrogen (TN) removal efficiencies were 91% at 15-20 °C and 18% at 3-6 °C, respectively. When HRT increased to 24 h, the average TN removal increased accordingly to 41% at 3-6 °C, suggesting denitrification performance was improved by extended HRT at low water temperatures. Due to denitrification, 96% of added nitrate nitrogen (NO3(-)-N) was converted to nitrogen gas, with a mean flux of nitrous oxide (N2O) was 0.0268-0.1500 ug m(-2) h(-1), while 98.86% of thiosulfate was gradually converted to sulfate throughout the system. Thus, our results show that the sulfur driven autotrophic denitrification constructed wetland demonstrated an excellent removal efficiency of nitrate for wastewater treatment. The HRT and water temperature proved to be two influencing factors in this constructed wetland treatment system. PMID:26766357

  11. Performance of completely autotrophic nitrogen removal over nitrite process under different aeration modes and dissolved oxygen

    Institute of Scientific and Technical Information of China (English)

    Jinsong GUO; Guohong YANG; Fang FANG; Yu QIN

    2008-01-01

    In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4+-N/L was fed into the reac-tors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8-1.0 mg/L. Whereas in the intermit-tently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0 2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and inter-mittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the inter-mittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process.

  12. Study of a combined heterotrophic and sulfur autotrophic denitrification technology for removal of nitrate in water

    International Nuclear Information System (INIS)

    A combined two-step process of heterotrophic denitrification in a fluidized reactor and sulfur autotrophic denitrification processes (CHSAD) was developed for the removal of nitrate in drinking water. In this process, the advantage of high efficiency of heterotrophic denitrification with non-excessive methanol and the advantage of non-pollution of sulfur autotriphic denitrification were integrated in this CHSAD process. And, this CHSAD process had the capacity of pH balance and could control the concentration of SO42- in effluent by adjusting the operation condition. When the influent nitrate was 30 mg NO3--N/L, the reactor could be operated efficiently at the hydraulic retention time (HRT) ranging from 20 to 40 min with C:N ratio (mg CH3OH:mg NO3--N) of 2.0 (methanol as carbon source). The nitrate removal was nearly 100% and there was no accumulated nitrite or residual methanol in the effluent. The effluent pH was about 7.5 and the sulfate concentration was lower than 130 mg/L. The maximum volume-loading rate of the reactor was 2.16 kg NO3--N/(m3 d). The biomass and scanning electron microscopy graphs of biofilm were also analyzed.

  13. Metabolic engineering of Cupriavidus necator for heterotrophic and autotrophic alka(e)ne production.

    Science.gov (United States)

    Crépin, Lucie; Lombard, Eric; Guillouet, Stéphane E

    2016-09-01

    Alkanes of defined carbon chain lengths can serve as alternatives to petroleum-based fuels. Recently, microbial pathways of alkane biosynthesis have been identified and enabled the production of alkanes in non-native producing microorganisms using metabolic engineering strategies. The chemoautotrophic bacterium Cupriavidus necator has great potential for producing chemicals from CO2: it is known to have one of the highest growth rate among natural autotrophic bacteria and under nutrient imbalance it directs most of its carbon flux to the synthesis of the acetyl-CoA derived polymer, polyhydroxybutyrate (PHB), (up to 80% of intracellular content). Alkane synthesis pathway from Synechococcus elongatus (2 genes coding an acyl-ACP reductase and an aldehyde deformylating oxygenase) was heterologously expressed in a C. necator mutant strain deficient in the PHB synthesis pathway. Under heterotrophic condition on fructose we showed that under nitrogen limitation, in presence of an organic phase (decane), the strain produced up to 670mg/L total hydrocarbons containing 435mg/l of alkanes consisting of 286mg/l of pentadecane, 131mg/l of heptadecene, 18mg/l of heptadecane, and 236mg/l of hexadecanal. We report here the highest level of alka(e)nes production by an engineered C. necator to date. We also demonstrated the first reported alka(e)nes production by a non-native alkane producer from CO2 as the sole carbon source. PMID:27212691

  14. Incidence of plant cover over the autotrophic nitrifying bacteria population in a fragment of Andean forest

    International Nuclear Information System (INIS)

    It was determined the incidence of plant cover (forest vs. pasture), on the autotrophy nitrifying bacteria, through the effect of biotic factors (radical exudate) and abiotic factors (temperature, ph and humidity), in a high mountain cloud forest fragment. The site of study was located near La Mesa (Cundinamarca) municipality. The temperature of soil was measured in situ, and soil samples were collected and carried to the laboratory for pH and humidity percentage measurements. Serial soil dilution method was used for plating samples on a selective culture medium with ammonium sulphate as nitrogen source, in order to estimate the autotrophic nitrifying bacteria population levels. Grown colonies were examined macro and microscopically. The quantity of nitrates produced by bacteria cultured in vitro was determined spectra-photometrical. In relation to the abiotic factors, there was no significant differences of pH between both plant covers, but there were significant for soil humidity and temperature (p<0.05). There were highly significant differences with respect to the bacteria population levels (p<0.0001) and with respect to nitrate production. This suggests a higher bacterial activity in the under forest cover. The radical exudate from both types of plant cover reduced the viability of bacteria in vitro, from 1:1 to 1:30 exudate bacteria proportions. In the soils physical and chemical analysis, it was found a higher P and Al concentrations, and a higher CIC and organic matter content under the forest cover. It is suggested the importance of this functional group in this ecosystem

  15. Exploratory Research - Using Volatile Organic Compounds to Separate Heterotrophic and Autotrophic Forest Soil Respiration

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Scott D [Mississippi State University; Hatten, Jeffrey A [Oregon State University

    2015-02-09

    The initial focus of this project was to develop a method to partition soil respiration into its components (autotrophic, heterotrophic etc.) using the fingerprint of volatile organic compounds (VOCs) from soils. We were able to identify 63 different VOCs in our study; however, due to technical difficulties we were unable to take reliable measurements in order to test our hypotheses and develop this method. In the end, we changed the objectives of the project. Our new objectives were to characterize the effects of species and soil moisture regime on the composition of soil organic matter. We utilized the soils from the greenhouse experiment we had established for the soil VOC study and determined the lignin biomarker profiles of each of the treatments. We found that moisture had a significant effect on the carbon content of the soils with the low moisture treatments having higher carbon content than the high moisture treatments. We found that the relative yield of syringyl phenols (SP), ligin (Lig), and substituted fatty acids (SFA) were elevated in deciduous planted pots and reduced in conifer planted pots relative to plant-free treatments. Our results suggest nuttall oak preserved lignin and SFA, while loblolly pine lost lignin and SFA similarly to the plant free treatments. Since we did not find that the carbon concentrations of the soils were different between the species, nuttall oak probably replaced more native soil carbon than loblolly pine. This suggests that relative to loblolly pine, nuttall oak is a priming species. Since priming may impact soil carbon pools more than temperature or moisture, determining which species are priming species may facilitate an understanding of the interaction that land use and climate change may have on soil carbon pools.

  16. Autotrophic carbon budget in coral tissue: a new 13C-based model of photosynthate translocation.

    Science.gov (United States)

    Tremblay, Pascale; Grover, Renaud; Maguer, Jean François; Legendre, Louis; Ferrier-Pagès, Christine

    2012-04-15

    Corals live in symbiosis with dinoflagellates of the genus Symbiodinum. These dinoflagellates translocate a large part of the photosynthetically fixed carbon to the host, which in turn uses it for its own needs. Assessing the carbon budget in coral tissue is a central question in reef studies that still vexes ecophysiologists. The amount of carbon fixed by the symbiotic association can be determined by measuring the rate of photosynthesis, but the amount of carbon translocated by the symbionts to the host and the fate of this carbon are more difficult to assess. In the present study, we propose a novel approach to calculate the budget of autotrophic carbon in the tissue of scleractinian corals, based on a new model and measurements made with the stable isotope (13)C. Colonies of the scleractinian coral Stylophora pistillata were incubated in H(13)CO (-)(3)-enriched seawater, after which the fate of (13)C was followed in the symbionts, the coral tissue and the released particulate organic carbon (i.e. mucus). Results obtained showed that after 15 min, ca. 60% of the carbon fixed was already translocated to the host, and after 48 h, this value reached 78%. However, ca. 48% of the photosynthetically fixed carbon was respired by the symbiotic association, and 28% was released as dissolved organic carbon. This is different from other coral species, where coral tissue after 48 h. Results show that our (13)C-based model could successfully trace the carbon flow from the symbionts to the host, and the photosynthetically acquired carbon lost from the symbiotic association. PMID:22442377

  17. Mutualism between autotrophic and heterophic bacteria in leaching of low grade ores

    International Nuclear Information System (INIS)

    During solubilization processes of low grade sulphidic ores, the auto trophic bacteria oxidize reduced sulphur compounds and ferrous iron to sulphates and ferric iron respectively. The ore leaching bio topes are not only colonized by auto trophic bacteria (Thiobacillus spp., Leptospirillum ferro oxidans and sulfolobus sp.) but the heterotrophic microorganisms, including bacteria and fungi of various species are also found in these habitats. The autotrophs, in addition to energy metabolism, also produce organic compounds which in excess amount inhibit their growth. Through the utilization of such compounds and also through the production of carbon dioxide and ammonia, these heterotorphs can help bio leaching processes. Effect of one of the heterotrophs; methylobacterium sp., a nitrogen scavenger, found in as association with the thio bacilli in one of the leaching bio tope in Germany was studied in leaching of a carbonate bearing complex (containing copper, iron, zinc and lead) sulphidic ore, in shake flask studies. T. ferro oxidans (Strain F-40) reported to be non nitrogen fixer and strain F-41, a nitrogen fixing thiobacillus were studied for leachability behaviour alone and in combination with T. thio oxidans (lacking nitrogen fixing ability) using media with and without added ammonium nitrogen. In addition the effect of methylobacterium sp. (alt-25) was also tested with the afore mentioned combinations. Nitrogen fixation by T. ferro oxidans did not suffice the nitrogen requirement and the leaching system in laboratory needed addition of nitrogen. The heterotrophic nitrogen scavenger also did not have a positive influence in nitrogen limited system. In case where ammonium nitrogen was also provided in the media, this heterotroph had a negative in own growth and leaving lesser amount available for thio bacilli. This high amount of acid is a limiting factor in bio leaching of high carbonate uranium ores. Uranium ore ecosystems have also been found to contain

  18. Autotrophic growth: methylated carbon monoxide dehydrogenase as an intermediate of acetyl-CoA synthesis

    International Nuclear Information System (INIS)

    A new pathway of autotrophic growth has been discovered in certain anaerobic bacteria in which acetyl-CoA is the product formed from CO2 for initiation of anabolism rather than 3-phosphoglycerate as in the Calvin Cycle. CO2 is reduced in combination with tetrahydrofolate to methyltetrahydrofolate (CH3THF) and is the source of the CH3 group. CO2 or CO is the source of the carbonyl group. CO dehydrogenase (CODH), corrinoid enzyme, methyltransferase, ferredoxin and CODH disulfide reductase have been isolated from Clostridium thermoaceticum and shown to catalyze the synthesis of acetyl-CoA from CH3THF, CO and CoA. The methyltransferase catalyzes transfer of the CH3 group from CH3THF to the corrinoid enzyme from which the methyl is transferred to CODH. CO is bound to the Ni of CODH forming a Ni-Fe-C center. When CO2 is the source of carbon, H2 and hydrogenase are required for reduction of the CO2 by CODH. CODH disulfide reductase is required for the addition of CoA to the CODH (Pezacka, E. and Wood, H.G. J. Biol. Chem., in press). Then, CODH catalyzes the combination of the three groups forming acetyl-CoA. The authors have now succeeded in methylating CODH using 14CH3I or 14CH3-B12. With the resulting 14CH3-CODH, only CODH disulfide reductase is required for synthesis of [14C]acetyl-CoA from CO and CoA. The amino acid sequence at the CH3-site is being investigated

  19. Partitioning Longleaf Pine Soil Respiration into Its Heterotrophic and Autotrophic Components through Root Exclusion

    Directory of Open Access Journals (Sweden)

    Althea A. ArchMiller

    2016-02-01

    Full Text Available Rapid and accurate estimations of the heterotrophic and autotrophic components of total soil respiration (Rs are important for calculating forest carbon budgets and for understanding carbon dynamics associated with natural and management-related disturbances. The objective of this study was to use deep (60 cm root exclusion tubes and paired control (i.e., no root exclusion collars to estimate heterotrophic respiration (Rh and Rs, respectively, in three 26-year-old longleaf pine (Pinus palustris Mill. stands in western Georgia. Root biomass was measured in root exclusion tubes and control collars after 102–104 days of incubation and fine root biomass loss from root exclusion was used to quantify root decay. Mean Rs from control collars was 3.3 micromol•CO2•m−2•s−1. Root exclusion tubes decreased Rs, providing an estimate of Rh. Mean Rh was 2.7 micromol•CO2•m−2•s−1 when uncorrected by pretreatment variation, root decay, or soil moisture compared to 2.1 micromol•CO2•m−2•s−1 when Rh was corrected for root decay. The corresponding ratio of Rh to Rs ranged from 66% to 82%, depending on the estimation method. This study provides an estimate of Rh in longleaf pine forests, and demonstrates the potential for deep root exclusion tubes to provide relatively rapid assessments (i.e., ~40 days post-treatment of Rh in similar forests. The range in Rh to Rs is comparable to other reports for similar temperate coniferous ecosystems.

  20. Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor 

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-mohammadi

    2013-02-01

    Full Text Available Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water.  Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

  1. Autotrophic antimonate bio-reduction using hydrogen as the electron donor.

    Science.gov (United States)

    Lai, Chun-Yu; Wen, Li-Lian; Zhang, Yin; Luo, Shan-Shan; Wang, Qing-Ying; Luo, Yi-Hao; Chen, Ran; Yang, Xiaoe; Rittmann, Bruce E; Zhao, He-Ping

    2016-01-01

    Antimony (Sb), a toxic metalloid, is soluble as antimonate (Sb(V)). While bio-reduction of Sb(V) is an effective Sb-removal approach, its bio-reduction has been coupled to oxidation of only organic electron donors. In this study, we demonstrate, for the first time, the feasibility of autotrophic microbial Sb(V) reduction using hydrogen gas (H2) as the electron donor without extra organic carbon source. SEM and EDS analysis confirmed the production of the mineral precipitate Sb2O3. When H2 was utilized as the electron donor, the consortium was able to fully reduce 650 μM of Sb(V) to Sb(III) in 10 days, a rate comparable to the culture using lactate as the electron donor. The H2-fed culture directed a much larger fraction of it donor electrons to Sb(V) reduction than did the lactate-fed culture. While 98% of the electrons from H2 were used to reduce Sb(V) by the H2-fed culture, only 12% of the electrons from lactate was used to reduce Sb(V) by the lactate-fed culture. The rest of the electrons from lactate went to acetate and propionate through fermentation, to methane through methanogenesis, and to biomass synthesis. High-throughput sequencing confirmed that the microbial community for the lactate-fed culture was much more diverse than that for the H2-fed culture, which was dominated by a short rod-shaped phylotype of Rhizobium (α-Protobacteria) that may have been active in Sb(V) reduction. PMID:26519630

  2. Carbon budgets for three autotrophic Australian estuaries: Implications for global estimates of the coastal air-water CO2 flux

    Science.gov (United States)

    Maher, D. T.; Eyre, B. D.

    2012-03-01

    Estuaries are `hot spots' in the global carbon cycle, yet data on carbon dynamics, in particular air-sea CO2 fluxes, from autotrophic systems are rare. Estuarine carbon budgets were constructed for three geomorphically distinct warm temperate Australian estuaries over an annual cycle. All three estuaries were net autotrophic, with annual net ecosystem metabolism (NEM) ranging from 8 ± 13.4 molC m-2 yr-1 to 10 ± 14 molC m-2 yr-1. There was a net flux of CO2 from the atmosphere to the estuaries of between 0.4 ± 0.6 molC m-2 yr-1 and 2 ± 0.9 molC m-2 yr-1. Loading of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) to the estuaries varied markedly within and between the estuaries, and was directly related to freshwater inflow. While NEM was similar in all three estuaries, the ratio of benthic versus pelagic contributions to NEM differed, with NEM dominated by pelagic production in the river dominated system, benthic production dominating in the intermediate estuary, and equal contributions of benthic and pelagic production in the marine dominated lagoon. All three estuaries exported more organic carbon than was imported, fueled by additional organic carbon supplied by NEM. The estuaries essentially acted as bioreactors, transforming DIC to organic carbon. Burial of organic carbon ranged from 1.2 ± 0.3 molC m-2 yr-1 to 4.4 ± 1.2 molC m-2 yr-1 and represented up to half of NEM. The annual net uptake of atmospheric CO2 in these systems, along with previous estimates of the global estuarine CO2flux being based predominantly on heterotrophic, large river dominated estuarine systems, indicates that the global estimate of the estuarine air-water CO2flux may be over-estimated due to the lack of studies from autotrophic marine dominated estuaries.

  3. Soil moisture sensitivity of autotrophic and heterotrophic forest floor respiration in boreal xeric pine and mesic spruce forests

    Science.gov (United States)

    Ťupek, Boris; Launiainen, Samuli; Peltoniemi, Mikko; Heikkinen, Jukka; Lehtonen, Aleksi

    2016-04-01

    Litter decomposition rates of the most process based soil carbon models affected by environmental conditions are linked with soil heterotrophic CO2 emissions and serve for estimating soil carbon sequestration; thus due to the mass balance equation the variation in measured litter inputs and measured heterotrophic soil CO2 effluxes should indicate soil carbon stock changes, needed by soil carbon management for mitigation of anthropogenic CO2 emissions, if sensitivity functions of the applied model suit to the environmental conditions e.g. soil temperature and moisture. We evaluated the response forms of autotrophic and heterotrophic forest floor respiration to soil temperature and moisture in four boreal forest sites of the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) by a soil trenching experiment during year 2015 in southern Finland. As expected both autotrophic and heterotrophic forest floor respiration components were primarily controlled by soil temperature and exponential regression models generally explained more than 90% of the variance. Soil moisture regression models on average explained less than 10% of the variance and the response forms varied between Gaussian for the autotrophic forest floor respiration component and linear for the heterotrophic forest floor respiration component. Although the percentage of explained variance of soil heterotrophic respiration by the soil moisture was small, the observed reduction of CO2 emissions with higher moisture levels suggested that soil moisture response of soil carbon models not accounting for the reduction due to excessive moisture should be re-evaluated in order to estimate right levels of soil carbon stock changes. Our further study will include evaluation of process based soil carbon models by the annual heterotrophic respiration and soil carbon stocks.

  4. Phototrophic biofilm assembly in microbial-mat-derived unicyanobacterial consortia: model systems for the study of autotroph-heterotroph interactions

    Directory of Open Access Journals (Sweden)

    StephenRLindemann

    2014-04-01

    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

  5. An operation protocol for facilitating start-up of single-stage autotrophic nitrogen removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan;

    2012-01-01

    Start-up and operation of single-stage nitritation/anammox reactor employing complete autotrophic nitrogen can be difficult. Keeping the performance criteria and monitoring the microbial community composition may not be easy or fast enough to take action on time. In this study, a control strategy...... is developed based on stoichiometric analysis of monitored nitrogen species. This analysis can serve as a strong decision-making tool to take appropriate actions with respect to the operational conditions to accelerate start up or attainment of near complete nitritation-anammox performance....

  6. Adaptation of the autotrophic acetogen Sporomusa ovata to methanol accelerates the conversion of CO2 to organic products

    DEFF Research Database (Denmark)

    Tremblay, Pier-Luc; Höglund, Daniel; Koza, Anna;

    2015-01-01

    Acetogens are efficient microbial catalysts for bioprocesses converting C1 compounds into organic products. Here, an adaptive laboratory evolution approach was implemented to adapt Sporomusa ovata for faster autotrophic metabolism and CO2 conversion to organic chemicals. S. ovata was first adapted...... increased 5-fold. Furthermore, acetate production rate from CO2 with an electrode serving as the electron donor was increased 6.5-fold confirming that the acceleration of the autotrophic metabolism of the adapted strain is independent of the electron donor provided. Whole-genome sequencing, transcriptomic....... The results demonstrate that an efficient strategy to increase rates of CO2 conversion in bioprocesses like microbial electrosynthesis is to evolve the microbial catalyst by adaptive laboratory evolution to optimize its autotrophic metabolism....

  7. Metabolic potential of microbial mats and microbialites: Autotrophic capabilities described by an in silico stoichiometric approach from shared genomic resources.

    Science.gov (United States)

    Cerqueda-García, Daniel; Falcón, Luisa I

    2016-08-01

    Microbialites and microbial mats are complex communities with high phylogenetic diversity. These communities are mostly composed of bacteria and archaea, which are the earliest living forms on Earth and relevant to biogeochemical evolution. In this study, we identified the shared metabolic pathways for uptake of inorganic C and N in microbial mats and microbialites based on metagenomic data sets. An in silico analysis for autotrophic pathways was used to trace the paths of C and N to the system, following an elementary flux modes (EFM) approach, resulting in a stoichiometric model. The fragility was analyzed by the minimal cut sets method. We found four relevant pathways for the incorporation of CO2 (Calvin cycle, reverse tricarboxylic acid cycle, reductive acetyl-CoA pathway, and dicarboxylate/4-hydroxybutyrate cycle), some of them present only in archaea, while nitrogen fixation was the most important source of N to the system. The metabolic potential to incorporate nitrate to biomass was also relevant. The fragility of the network was low, suggesting a high redundancy of the autotrophic pathways due to their broad metabolic diversity, and highlighting the relevance of reducing power source. This analysis suggests that microbial mats and microbialites are "metabolic pumps" for the incorporation of inorganic gases and formation of organic matter. PMID:27324427

  8. Bioleaching mechanism of Zn, Pb, In, Ag, Cd and As from Pb/Zn smelting slag by autotrophic bacteria.

    Science.gov (United States)

    Wang, Jia; Huang, Qifei; Li, Ting; Xin, Baoping; Chen, Shi; Guo, Xingming; Liu, Changhao; Li, Yuping

    2015-08-15

    A few studies have focused on release of valuable/toxic metals from Pb/Zn smelting slag by heterotrophic bioleaching using expensive yeast extract as an energy source. The high leaching cost greatly limits the practical potential of the method. In this work, autotrophic bioleaching using cheap sulfur or/and pyrite as energy matter was firstly applied to tackle the smelting slag and the bioleaching mechanisms were explained. The results indicated autotrophic bioleaching can solubilize valuable/toxic metals from slag, yielding maximum extraction efficiencies of 90% for Zn, 86% for Cd and 71% for In, although the extraction efficiencies of Pb, As and Ag were poor. The bioleaching performance of Zn, Cd and Pb was independent of leaching system, and leaching mechanism was acid dissolution. A maximum efficiency of 25% for As was achieved by acid dissolution in sulfursulfur oxidizing bacteria (S-SOB), but the formation of FeAsO4 reduced extraction efficiency in mixed energy source - mixed culture (MS-MC). Combined works of acid dissolution and Fe(3+) oxidation in MS-MC was responsible for the highest extraction efficiency of 71% for In. Ag was present in the slag as refractory AgPb4(AsO4)3 and AgFe2S3, so extraction did not occur. PMID:25996622

  9. Interactions of the metal tolerant heterotrophic microorganisms and iron oxidizing autotrophic bacteria from sulphidic mine environment during bioleaching experiments.

    Science.gov (United States)

    Jeremic, Sanja; Beškoski, Vladimir P; Djokic, Lidija; Vasiljevic, Branka; Vrvić, Miroslav M; Avdalović, Jelena; Gojgić Cvijović, Gordana; Beškoski, Latinka Slavković; Nikodinovic-Runic, Jasmina

    2016-05-01

    Iron and sulfur oxidizing chemolithoautotrophic acidophilic bacteria, such as Acidithiobacillus species, hold the dominant role in mine environments characterized by low pH values and high concentrations of reduced sulfur and iron compounds, such as ores, rocks and acid drainage waters from mines. On the other hand, heterotrophic microorganisms, especially their biofilms, from these specific niches are receiving increased attention, but their potential eco-physiological roles have not been fully understood. Biofilms are considered a threat to human health, but biofilms also have beneficial properties as they are deployed in waste recycling and bioremediation systems. We have analyzed interactions of the metal tolerant heterotrophic microorganisms in biofilms with iron oxidizing autotrophic bacteria both from the sulphidic mine environment (copper mine Bor, Serbia). High tolerance to Cu(2+), Cd(2+) and Cr(6+) and the presence of genetic determinants for the respective metal tolerance and biofilm-forming ability was shown for indigenous heterotrophic bacteria that included strains of Staphylococcus and Rhodococcus. Two well characterized bacteria- Pseudomonas aeruginosa PAO1 (known biofilm former) and Cupriavidus metallidurans CH34 (known metal resistant representative) were also included in the study. The interaction and survivability of autotrophic iron oxidizing Acidithiobacillus bacteria and biofilms of heterotrophic bacteria during co-cultivation was revealed. Finally, the effect of heterotrophic biofilms on bioleaching process with indigenous iron oxidizing Acidithiobacillus species was shown not to be inhibitory under in vitro conditions. PMID:26942859

  10. 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.

    2014-04-07

    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.

  11. Extraction and structural characteristics of extracellular polymeric substances (EPS), pellets in autotrophic nitrifying biofilm and activated sludge.

    Science.gov (United States)

    Liang, Zhiwei; Li, Wenhong; Yang, Shangyuan; Du, Ping

    2010-10-01

    The composition and the distribution of extracellular polymeric substances (EPS) and pellets of autotrophic nitrifying biofilm and activated sludge were investigated in this work. Fourier-transform Infrared Spectroscopy, fluorescent in situ hybridization and fluorescence staining were used to examine proteins, carbohydrates, humic substances and DNA being present in the biofilms and the sludge samples. To investigate extraction efficiency and its effect on characterization of tightly bounded EPS, four extraction methods (ethylenediamine tetraacetic acid (EDTA), NaOH, cationic exchange resin (CER), ultrasound) were compared. EDTA and ultrasound showed more effective extraction ability than NaOH and CER. NaOH and ultrasound extraction led to high activity of glucose-6-phosphate dehydrogenase from cell lysis, which was confirmed by fluorescence staining analysis. Ultrasound and NaOH extraction yielded 18% and 11% of dead cells in biofilm, respectively, whereas they obtained 11% and 9% of dead cells in activated sludge, respectively. Four layers of extractible products were separated from autotrophic nitrifiering flocs. The extraction results indicated that extraction yield in different layers varied in a wide range: 3-6% of soluble EPS, 5-10% of loosely bound EPS, 34-67% of tightly bound EPS and 30-60% of pellets. PMID:20655088

  12. Characterization of the start-up period of single-step autotrophic nitrogen removal in a sequencing batch reactor

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-song; QIN Yu; FANG Fang; YANG Guo-hong

    2008-01-01

    The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen (DO), hydraulic retention time (HRT) and temperature controlled. The experimental conditions were temperature at (30(2) (C, ammonia concentration of (60 to 120) mg/L, DO of (0.8 to 1.0) mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation: sludge domestication, nitrifying bacteria selection and sludge adaptation. It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.

  13. Performance of a completely autotrophic nitrogen removal over nitrite process for treating wastewater with different substrates at ambient temperature

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Chang; Dong Li; Yuhai Liang; Zhuo Yang; Shaoming Cui; Tao Liu; Huiping Zeng

    2013-01-01

    The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated.The completely autotrophic nitrogen removal over nitrite (CANON) reactor was fed with different concentrations of ammonia (400,300,and 200 mg N/L) but constant influent ammonia load.The results showed that the CANON system can achieve good treatment performance at ambient temperature (15-23℃).The average removal rate and removal loading of NH4 +-N and TN was 83.90%,1.26 kg N/(m3.day),and 70.14%,1.09 kg N/(m3.day),respectively.Among the influencing factors like pH,dissolved oxygen and alkalinity,it was indicated that the pH was the key parameter of the performance of the CANON system.Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way.Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria,which had low diversity in different stages,while the species of anaerobic ammonium oxidizing (anammox) bacteria were fewer and the community composition was relatively stable.These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation,which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.

  14. Effect of inorganic carbon on the completely autotrophic nitrogen removal over nitrite (CANON) process in a sequencing batch biofilm reactor.

    Science.gov (United States)

    Chen, You-Peng; Li, Shan; Fang, Fang; Guo, Jin-Song; Zhang, Qiang; Gao, Xu

    2012-12-01

    Ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AnAOB) are autotrophic microorganisms. Inorganic carbon (IC) is their main carbon source. The effects of IC limitation on AOB and AnAOB in the completely autotrophic nitrogen removal over nitrite (CANON) process in a sequencing batch biofilm reactor (SBBR) were examined. The optimal IC concentration in the influent was investigated. The start-up time of the CANON process from the activated sludge in the SBBR was 80 d under controlled free ammonia (FA) conditions and sufficient IC source. The AOB and AnAOB activities were limited by an IC concentration of 50 mg-C-L(-1) in the influent, whilst the nitrogen loading rate (NLR) was 200 mg-N x L(-1) x d(-1). The experiment on recovering the influent IC showed that AOB and AnAOB activities were affected by the IC limitation, and not by the pH or FA, at 200mg-N x L(-1) x d(-1) NLR and 50mg-C x L(-1) IC in the CANON process. The activities were recovered by increasing the IC concentration in the influent. From an economic point of view, the optimal IC concentration in the influent was 250mg-C x L(-1) at 200mg-N x L(-1) x d(-1) NLR in this CANON system. PMID:23437661

  15. Summer monsoon onset-induced changes of autotrophic pico- and nanoplankton in the largest monsoonal estuary along the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Mohan, A.P.; Jyothibabu, R.; Jagadeesan, L.; Lallu, K.R.; Karnan, C.

        Environ. Monit. Assess., vol.188; 2016; no.93 doi: 10.1007/s10661-016-5096-7 Summer Monsoon Onset -induced Changes of Autotrophic Pico - and Nano - plankton in the Largest Monsoonal Estuary along the West Coast of India Arya P. Mohan, Jyothibabu, R...: Phytoplankton, Synechococcus, Prochlorococcus, Picoeukaryotes, Cochin Backwaters  2    1. Introduction Smaller autotrophic plankton consist of pico - (0.2 - 2 μm) and nano - (2 - 20 μm) size ranges inhabiting the euphotic ocean surface layer. Earlier studies...

  16. Potential autotrophic metabolisms in ultra-basic reducing springs associated with present-day continental serpentinization

    Science.gov (United States)

    Morrill, P. L.; Miles, S.; Kohl, L.; Kavanagh, H.; Ziegler, S. E.; Brazelton, W. J.; Schrenk, M. O.

    2013-12-01

    Ultra-basic reducing springs at continental sites of serpentinization act as windows into the biogeochemistry of this subsurface exothermic environment rich in H2 and CH4 gases. Biogeochemical carbon transformations in these systems are of interest because serpentinization creates conditions that are amenable to abiotic and biotic reduction of carbon. However, little is known about the metabolic capabilities of the microorganisms that live in this environment. To determine the potential for autotrophic metabolisms, bicarbonate and CO substrate addition microcosm experiments were performed using water and sediment from an ultra-basic reducing spring in the Tablelands, Newfoundland, Canada, a site of present-day continental serpentinization. CO was consistently observed to be utilized in the Live but not the Killed controlled replicates amended with 10% 13C labelled CO and non-labelled (natural C isotope abundance) CO. In the Live CO microcosms with natural C isotope abundance, the residual CO became enriched in 13C (~10 ‰) consistent with a decrease in the fraction of CO remaining. In the Killed CO controlled replicates with natural C isotope abundance the CO showed little 13C enrichment (~1.3 ‰). The data from the Live CO microcosms were well described by a Rayleigh isotopic distillation model, yielding an isotopic enrichment factor for microbial CO uptake of 15.7 ×0.5 ‰ n=2. These data suggest that there was microbial CO utilization in these experiments. The sediment and water from the 13C-labelled and non-labelled, Live and Killed microcosms were extracted for phospholipid fatty acids (PLFAs) to determine changes in community composition between treatments as well as to determine the microbial uptake of CO. The difference in community composition between the Live and Killed microcosms was not readily resolvable based on PLFA distributions. Additionally, the microbial uptake of 13CO had minimal to no affect on the δ13C of the cellular biomarkers, with the

  17. Regulation of Autotrophic and Heterotrophic Metabolism in Pseudomonas oxalaticus OX1. Growth on Fructose and on Mixtures of Fructose and Formate in Batch and Continuous Cultures

    NARCIS (Netherlands)

    Dijkhuizen, L.; Harder, W.

    1984-01-01

    In Pseudomonas oxalaticus the synthesis of enzymes involved in autotrophic CO2 fixation via the Calvin cycle is regulated by repression/derepression. During growth of the organism on fructose alone, the synthesis of ribulosebisphosphate carboxylase (RuBPCase) remained fully repressed, both in batch

  18. Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park.

    Science.gov (United States)

    Moran, James J; Whitmore, Laura M; Isern, Nancy G; Romine, Margaret F; Riha, Krystin M; Inskeep, William P; Kreuzer, Helen W

    2016-05-01

    The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonensis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with (13)C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community. PMID:26995682

  19. Aeration control by monitoring the microbiological activity using fuzzy logic diagnosis and control. Application to a complete autotrophic nitrogen removal reactor

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine;

    2015-01-01

    microbial groups on the other hand, the diagnosis provides information on: nitritation, nitratation, anaerobic ammonium oxidation and overall autotrophic nitrogen removal. These four results give insight into the state of the process and are used as inputs for the controller that manipulates the aeration to...

  20. Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park

    Energy Technology Data Exchange (ETDEWEB)

    Moran, James J.; Whitmore, Laura M.; Isern, Nancy G.; Romine, Margaret F.; Riha, Krystin M.; Inskeep, William P.; Kreuzer, Helen W.

    2016-03-19

    The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonesis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with 13C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community.

  1. Effects of dissolved oxygen on microbial community of single-stage autotrophic nitrogen removal system treating simulating mature landfill leachate.

    Science.gov (United States)

    Wen, Xin; Zhou, Jian; Wang, Jiale; Qing, Xiaoxia; He, Qiang

    2016-10-01

    The performance of four identical sequencing biofilm batch reactors (SBBR) for autotrophic nitrogen removal was investigated with 2000mg/L ammonia-containing mature landfill leachate at 30°C. The main objective of this study was to evaluate the effects of dissolved oxygen (DO) on the performance and microbial community of single-stage nitrogen removal using anammox and partial nitritation (SNAP) system. At an applied load of 0.5kgNm(-3)d(-1), average total nitrogen removal efficiency (TNRE) above 90% was long-term achieved with an optimal DO concentration of 2.7mg/L. The microelectrode-measured profiles showed the microenvironments inside the biofilms. 16S ribosomal Ribonucleic Acid (rRNA) amplicon pyrosequencing and denaturing gradient gel electrophoresis (DGGE) were used to analyze the microbial variations of different DO concentrations and different positions inside one reactor. PMID:27450126

  2. Autotrophic growth and lipid production of Chlorella sorokiniana in lab batch and BIOCOIL photobioreactors: Experiments and modeling.

    Science.gov (United States)

    Concas, Alessandro; Malavasi, Veronica; Costelli, Cristina; Fadda, Paolo; Pisu, Massimo; Cao, Giacomo

    2016-07-01

    A novel mathematical model for the quantitative assessment of the effect of dissolved nitrogen on the autotrophic batch-growth and lipid accumulation of Chlorella sorokiniana, is proposed in this work. Model results have been validated through comparison with suitable experimental data performed in lab photobioreactors. Further experiments have been then performed using the BIOCOIL photobioreactor operated in fed-batch mode. The experimental results, which show that a maximum growth rate of 0.52day(-1) and a lipid content equal to 25%wt can be achieved with the BIOICOIL, have been successfully predicted through the proposed model. Therefore, the model might represent a first step toward the development of a tool for the scale-up and optimization of the operating conditions of BIOCOIL photobioreactors. Finally, the fatty acid methyl esters obtained by trans-esterification of lipids extracted from C. sorokiniana, have been analyzed in view of the assessment of their usability for producing biodiesel. PMID:27030952

  3. Impact of CO2 concentration on autotrophic metabolisms and carbon fate in saline aquifers - A case study

    Science.gov (United States)

    Dupraz, Sebastien; Fabbri, Antonin; Joulian, Catherine; Dictor, Marie-Christine; Battaglia-Brunet, Fabienne; Ménez, Bénédicte; Crouzet, Catherine; Henry, Benoît; Garrido, Francis

    2013-10-01

    The purpose of this study was to identify and quantify the fate and speciation of carbon that can occur in mixtures of geological media (crushed rock) and autotrophic microbial communities. A sulfate reducing bacterium (Desulfotomaculum geothermicum) and a methanogenic archaeon (Methanothermococcus thermolithotrophicus) were both tested separately and together, with and without crushed sedimentary rock (carbonaceous sandstone) for different CO2 partial pressures (0.22, 0.88, 3.52, and 8 bar) at 54 °C in saline artificial groundwater. In order to quantify the respective metabolic activities, the inorganic gases of interest (H2, CH4, H2S and CO2) were measured and the speciation of carbon was assessed by measuring volatile, non-purgeable, total and dissolved organic carbon as well as total and dissolved inorganic carbon. Despite a protective effect of the mineral matrix, the results showed a high sensitivity of autotrophic microorganisms to the stress induced by pressures of CO2 superior to one bar and revealed that a part of this stress was due to direct toxic effects. M. thermolithotrophicus demonstrated a better tolerance to CO2 and was dominating the consortia. This ascendancy was interpreted as resulting from equilibrium displacement due to transport effects of methane between the liquid and gas phases. Abiotic dissolution was observed but some biomineralization processes of carbonates were also identified for D. geothermicum. Both strains displayed very different patterns in their conversion of inorganic carbon: while M. thermolithotrophicus was mainly producing methane, D. geothermicum induced the formation of biomass. The availability of crushed rock increased the proportion of sessile biofilms. All these results were analyzed in correlation with a successful PHREEQC simulation and demonstrate the strong influence of the microbial activities and diversity on the carbon fate in the immediate surroundings of geological CCS storage zones.

  4. The effect of clay particles on the activity of suspended autotrophic nitrifying bacteria and on the performance of an air-lift reactor

    OpenAIRE

    Vieira, M. J.; Pacheco, A. P.; I. A. Pinho; Melo, L. F.

    2001-01-01

    Clay minerals have some properties, namely a high surface area and the ability of ion exchange that may exert some effects on microbial systems. It is often difficult to know the way the clay is exerting its influence and whether its presence improves a given metabolic process The present work concerns the study of the effect of the addition of Powdered kaolin to autotrophic nitrification systems, and includes the study of the effects of the particles on the activity of a suspended nitrifying...

  5. Abundances of Hyperthermophilic Autotrophic Fe(III) Oxide Reducers and Heterotrophs in Hydrothermal Sulfide Chimneys of the Northeastern Pacific Ocean ▿ †

    OpenAIRE

    Ver Eecke, Helene C.; Kelley, Deborah S.; Holden, James F.

    2008-01-01

    The abundances of hyperthermophilic heterotrophs, methanogens, and autotrophic reducers of amorphous Fe(III) oxide in 18 samples of deep-sea hydrothermal vent sulfide chimneys of the Endeavour Segment were measured. The results indicate that conditions favor the growth of iron reducers toward the interiors of these deposits and that of heterotrophs toward the outer surfaces near high-temperature polychaete worms (Paralvinella sulfincola).

  6. Abundances of Hyperthermophilic Autotrophic Fe(III) Oxide Reducers and Heterotrophs in Hydrothermal Sulfide Chimneys of the Northeastern Pacific Ocean ▿ †

    Science.gov (United States)

    Ver Eecke, Helene C.; Kelley, Deborah S.; Holden, James F.

    2009-01-01

    The abundances of hyperthermophilic heterotrophs, methanogens, and autotrophic reducers of amorphous Fe(III) oxide in 18 samples of deep-sea hydrothermal vent sulfide chimneys of the Endeavour Segment were measured. The results indicate that conditions favor the growth of iron reducers toward the interiors of these deposits and that of heterotrophs toward the outer surfaces near high-temperature polychaete worms (Paralvinella sulfincola). PMID:18978076

  7. Coupling between anammox and autotrophic denitrification for simultaneous removal of ammonium and sulfide by enriched marine sediments.

    Science.gov (United States)

    Rios-Del Toro, E Emilia; Cervantes, Francisco J

    2016-06-01

    In the present study, the capacity of enrichments derived from marine sediments collected from different sites of the Mexican littoral to perform anaerobic ammonium oxidation (anammox) coupled to sulfide-dependent denitrification for simultaneous removal of ammonium and sulfide linked to nitrite reduction was evaluated. Sulfide-dependent denitrification out-competed anammox during the simultaneous oxidation of sulfide and ammonium. Significant accumulation of elemental sulfur (ca. 14-30 % of added sulfide) occurred during the coupling between the two respiratory processes, while ammonium was partly oxidized (31-47 %) due to nitrite limitation imposed in sediment incubations. Nevertheless, mass balances revealed up to 38 % more oxidation of the electron donors available (ammonium and sulfide) than that expected from stoichiometry. Recycling of nitrite, from nitrate produced through anammox, is proposed to contribute to extra oxidation of sulfide, while additional ammonium oxidation is suggested by sulfate-reducing anammox (SR-anammox). The complex interaction between nitrogenous and sulfurous compounds occurring through the concomitant presence of autotrophic denitrification, conventional anammox and SR-anammox may significantly drive the nitrogen and sulfur fluxes in marine environments. PMID:26994921

  8. [Single-stage autotrophic nitrogen removal reactor with self-generated granular sludge for treating sludge dewatering effluent].

    Science.gov (United States)

    Cao, Jian-ping; Du, Bing; Liu, Yin; Qin, Yong-sheng

    2009-10-15

    Single-stage autotrophic nitrogen removal (SANR) has been observed in a long-term operated nitrosation air-lift reactor for treating digested sludge dewatering effluent from sewage wastewater treatment plant. A kind of so called self-generated granular sludge which undertake the SANR reaction has oriented formed. The performance of SANR reactor cultivated above sludge for treating sludge dewatering effluent has been tested and better results have been reached. When the influent total nitrogen (TN) was kept about 350 mg/L (mainly ammonium nitrogen), the average TN removal efficiency and nitrogen removal load were 74.8% (maximum 86.92%) and 0.68 kg x (m3 x d)(-1) [maximum 0.9 kg x (m3 x d)(-1)] respectively. The operation stability and nitrogen removal efficiency have been enforced after adding a certain quantity powered activated carbon. The influent ammonium concentration, nitrogen load and aeration rate have a great effect on SANR reactor as well as the influent organic compound, pH, alkalinity have a relatively low effect. The parameters such as the ratios of aeration rate/deltaTN, aeration rate/deltaNH4+ -N, deltaALK/deltaTN can be used for better controlling the reaction. PMID:19968119

  9. Extraction and characterization of extracellular polymeric substances in biofilm and sludge via completely autotrophic nitrogen removal over nitrite system.

    Science.gov (United States)

    Chen, You-Peng; Li, Chun; Guo, Jin-Song; Fang, Fang; Gao, Xu; Zhang, Peng; Li, Shan

    2013-01-01

    Extracellular polymeric substances (EPS) were extracted from sludge and biofilm via the completely autotrophic nitrogen removal over nitrite (CANON) system. Tightly bound (TB)-EPS were extracted using four physical methods, namely, cationic exchange resin (CER), sonication, heating, and steaming. CER was the most effective and most suitable method for extraction among the four methods. Moreover, the ultraviolet-vis spectra of TB-EPS indicated that few cells were destroyed by the CER method. The major component contents of total EPS, proteins, carbohydrates, humic substances, and DNA in sludge were 60.77, 49.84, 21.63, and 9.01 mg/g volatile suspended solids (VSS) and 90.03, 29.01, 15.96, and 10.04 mg/g VSS in biofilm, respectively. The Fourier transform infrared (FT-IR) spectra results indicated differences in the EPS functional groups between biofilm and sludge. The results of the batch experiments showed that the biofilm activity was significantly higher than that of the sludge in the CANON system. Furthermore, biomass activity was probably influenced by the EPS composition and distribution in the sludge and biofilm. PMID:23239415

  10. Autotrophic hydrogen photoproduction by operation of carbon-concentrating mechanism in Chlamydomonas reinhardtii under sulfur deprivation condition.

    Science.gov (United States)

    Hong, Min Eui; Shin, Ye Sol; Kim, Byung Woo; Sim, Sang Jun

    2016-03-10

    Under autotrophic conditions, starch plays an important role in establishing anoxic conditions during PSII-dependent hydrogen (H2) photoproduction in microalgae. This is because starch is the sole organic substrate during respiratory consumption of internal oxygen (O2) from PSII-dependent direct pathway. Herein, we propose a novel approach to further facilitate the internal starch synthesis of Chlamydomonas reinhardtii through the operation of carbon-concentrating mechanism (CCM) along with a two-stage process based on sulfur (S) deprivation, thereby resulting in enhanced anaerobic capacity during PSII-dependent H2 photoproduction. When CCM-induced cells were exposed to high levels of carbon dioxide (CO2) (5%, v/v) with S deprivation, internal levels of starch were significantly elevated by retaining a functional CCM with the boosted photosynthetic activity during 24h of O2 evolution phase (I) of S deprivation. Consequently, during H2 production phase of S deprivation at irradiance of 50μEm(-2)s(-1), the concentrations of starch and H2 in CCM-induced cells were remarkably enhanced by 65.0% and 218.9% compared to that of CCM-uninduced cells, respectively. The treatment of low-CO2-driven CCM induction prior to S deprivation is a cost-effective and energy-efficient strategy that significantly improves the solar-driven H2 production by microalgae; this is particularly realizable in an industrial scale. PMID:26812657

  11. Potential for large-bodied zooplankton and dreissenids to alter the productivity and autotrophic structure of lakes.

    Science.gov (United States)

    Higgins, Scott N; Althouse, B; Devlin, S P; Vadeboncoeur, Y; Vander Zanden, M J

    2014-08-01

    While limnological studies have emphasized the importance of grazers on algal biomass and primary production in pelagic habitats, few studies have examined their potential role in altering total ecosystem primary production and it's partitioning between pelagic and benthic habitats. We modified an existing ecosystem production model to include biotic feedbacks associated with two groups of large-bodied grazers of phytoplankton (large-bodied zooplankton and dreissenid mussels) and estimated their effects on total ecosystem production (TEP), and the partitioning of TEP between phytoplankton and periphyton (autotrophic structure) across large gradients in lake size and total phosphorus (TP) concentration. Model results indicated that these filter feeders were capable of reducing whole-lake phytoplankton production by 20-70%, and increasing whole-lake benthic production between 0% and 600%. Grazer effects on TEP were constrained by lake size, trophic status, and potential feedbacks between grazing and maximum rates of benthic photosynthesis (BP(MAX)). In small (mean depth Z 100 m), Bf was minor (< 10%) in the presence or absence of grazers, but increases in littoral habitat and the stimulation of benthic production in these ecosystems could be of ecological relevance because littoral zones in large lakes contain a relatively high proportion of within-lake biodiversity and are important for whole-lake food webs. PMID:25230476

  12. Nitrate-dependent anaerobic ferrous oxidation (NAFO) by denitrifying bacteria: a perspective autotrophic nitrogen pollution control technology.

    Science.gov (United States)

    Zhang, Meng; Zheng, Ping; Wang, Ru; Li, Wei; Lu, Huifeng; Zhang, Jiqiang

    2014-12-01

    The nitrate-dependent anaerobic ferrous oxidation (NAFO) is an important discovery in the fields of microbiology and geology, which is a valuable biological reaction since it can convert nitrate into nitrogen gas, removing nitrogen from wastewater. The research on NAFO can promote the development of novel autotrophic biotechnologies for nitrogen pollution control and get a deep insight into the biogeochemical cycles. In this work, batch experiments were conducted with denitrifying bacteria as biocatalyst to investigate the performance of nitrogen removal by NAFO. The results showed that the denitrifying bacteria were capable of chemolithotrophic denitrification with ferrous salt as electron donor, namely NAFO. And the maximum nitrate conversion rates (qmax) reached 57.89 mg (g VSS d)−1, which was the rate-limiting step in NAFO. Fe/N ratio, temperature and initial pH had significant influences on nitrogen removal by NAFO process, and their optimal values were 2.0 °C, 30.15 °C and 8.0 °C, respectively. PMID:25461924

  13. Performance of nitrate-dependent anaerobic ferrous oxidizing (NAFO) process: a novel prospective technology for autotrophic denitrification.

    Science.gov (United States)

    Zhang, Meng; Zheng, Ping; Li, Wei; Wang, Ru; Ding, Shuang; Abbas, Ghulam

    2015-03-01

    Nitrate-dependent anaerobic ferrous oxidizing (NAFO) is a valuable biological process, which utilizes ferrous iron to convert nitrate into nitrogen gas, removing nitrogen from wastewater. In this work, the performance of NAFO process was investigated as a nitrate removal technology. The results showed that NAFO system was feasible for autotrophic denitrification. The volumetric loading rate (VLR) and volumetric removal rate (VRR) under steady state were 0.159±0.01 kg-N/(m(3) d) and 0.073±0.01 kg-N/(m(3) d), respectively. In NAFO system, the effluent pH was suggested as an indicator which demonstrated a good correlation with nitrogen removal. The nitrate concentration was preferred to be less than 130 mg-N/L. Organic matters had little influence on NAFO performance. Abundant iron compounds were revealed to accumulate in NAFO sludge with peak value of 51.73% (wt), and they could be recycled for phosphorus removal, with capacity of 16.57 mg-P/g VS and removal rate of 94.77±2.97%, respectively. PMID:25576990

  14. A Genetic System for Clostridium ljungdahlii: a Chassis for Autotrophic Production of Biocommodities and a Model Homoacetogen

    Energy Technology Data Exchange (ETDEWEB)

    Leang, C; Ueki, T; Nevin, KP; Lovley, DR

    2013-02-04

    Methods for genetic manipulation of Clostridium ljungdahlii are of interest because of the potential for production of fuels and other biocommodities from carbon dioxide via microbial electrosynthesis or more traditional modes of autotrophy with hydrogen or carbon monoxide as the electron donor. Furthermore, acetogenesis plays an important role in the global carbon cycle. Gene deletion strategies required for physiological studies of C. ljungdahlii have not previously been demonstrated. An electroporation procedure for introducing plasmids was optimized, and four different replicative origins for plasmid propagation in C. ljungdahlii were identified. Chromosomal gene deletion via double-crossover homologous recombination with a suicide vector was demonstrated initially with deletion of the gene for FliA, a putative sigma factor involved in flagellar biogenesis and motility in C. ljungdahlii. Deletion of fliA yielded a strain that lacked flagella and was not motile. To evaluate the potential utility of gene deletions for functional genomic studies and to redirect carbon and electron flow, the genes for the putative bifunctional aldehyde/alcohol dehydrogenases, adhE1 and adhE2, were deleted individually or together. Deletion of adhE1, but not adhE2, diminished ethanol production with a corresponding carbon recovery in acetate. The double deletion mutant had a phenotype similar to that of the adhE1-deficient strain. Expression of adhE1 in trans partially restored the capacity for ethanol production. These results demonstrate the feasibility of genetic investigations of acetogen physiology and the potential for genetic manipulation of C. ljungdahlii to optimize autotrophic biocommodity production.

  15. Autotrophic and heterotrophic metabolism of microbial planktonic communities in an oligotrophic coastal marine ecosystem: seasonal dynamics and episodic events

    Directory of Open Access Journals (Sweden)

    O. Bonilla-Findji

    2010-03-01

    Full Text Available A 18 month study was performed in the Bay of Villefranche to assess the episodic and seasonal variation of autotrophic and heterotrophic ecosystem processes. A typical spring bloom was encountered, where maximum of gross primary production (GPP was followed by maxima of bacterial respiration (BR and production (BP. The trophic balance (heterotrophy vs. autotrophy of the system did not exhibit any seasonal trend although a strong intra-annual variability was observed. On average, the community tended to be net heterotrophic with a GPP threshold for a balanced metabolism of 2.8 μmol O2 l−1 d−1. Extended forest fires in summer 2003 and a local episodic upwelling in July 2003 likely supplied orthophosphate and nitrate into the system. These events were associated with an enhanced bacterioplankton production (up to 2.4-fold, respiration (up to 4.5-fold and growth efficiency (up to 2.9-fold but had no effect on GPP. A Sahara dust wet deposition event in February 2004 stimulated bacterial abundance, production and growth efficiency but not GPP. Our study suggests that short-term disturbances such as wind-driven upwelling, forest fires and Sahara dust depositions can have a significant but previously not sufficiently considered influence on phytoplankton- and bacterioplankton-mediated ecosystem functions and can modify or even mask the seasonal dynamics. The study also indicates that atmospheric deposition of nutrients and particles not only impacts phytoplankton but also bacterioplankton and could, at times, also shift systems stronger towards net heterotrophy.

  16. Autotrophic and heterotrophic metabolism of microbial planktonic communities in an oligotrophic coastal marine ecosystem: seasonal dynamics and episodic events

    Directory of Open Access Journals (Sweden)

    O. Bonilla-Findji

    2010-11-01

    Full Text Available A 18 month study was performed in the Bay of Villefranche to assess the episodic and seasonal variation of autotrophic and heterotrophic ecosystem processes. A typical spring bloom was encountered, where maximum of gross primary production (GPP was followed by maxima of bacterial respiration (BR and production (BP. The trophic balance (heterotrophy vs. autotrophy of the system did not exhibit any seasonal trend although a strong intra-annual variability was observed. On average, the community tended to be net heterotrophic with a GPP threshold for a balanced metabolism of 1.1 μmol O2 l−1 d−1. Extended forest fires in summer 2003 and a local episodic upwelling in July 2003 likely supplied orthophosphate and nitrate into the system. These events were associated with an enhanced bacterioplankton production (up to 2.4-fold, respiration (up to 4.5-fold and growth efficiency (up to 2.9-fold but had no effect on GPP. A Sahara dust wet deposition event in February 2004 stimulated bacterial abundance, production and growth efficiency but not GPP. Our study suggests that short-term disturbances such as wind-driven upwelling, forest fires and Sahara dust depositions can have a significant but previously not sufficiently considered influence on phytoplankton- and bacterioplankton-mediated ecosystem functions and can modify or even mask the seasonal dynamics. The study also indicates that atmospheric deposition of nutrients and particles not only impacts phytoplankton but also bacterioplankton and could, at times, also shift systems stronger towards net heterotrophy.

  17. Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

    Directory of Open Access Journals (Sweden)

    E. González-Toril

    2009-01-01

    Full Text Available Four different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area and the Andes (Nevado Illimani summit, Bolivia, from Antarctic aerosol (French station Dumont d'Urville and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas, in a minimal mineral (oligotrophic media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria Alpha-, Beta- and Gamma-proteobacteria, Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified and the marine Antarctic soil the poorest (only one. Snow samples from Col du Midi (Alps and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones. These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteriaclone. The only microorganism identified in the Antarctica soil (Brevundimonas sp. was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other.

  18. Autotrophic nitrogen assimilation and carbon capture for microbial protein production by a novel enrichment of hydrogen-oxidizing bacteria.

    Science.gov (United States)

    Matassa, Silvio; Verstraete, Willy; Pikaar, Ilje; Boon, Nico

    2016-09-15

    Domestic used water treatment systems are currently predominantly based on conventional resource inefficient treatment processes. While resource recovery is gaining momentum it lacks high value end-products which can be efficiently marketed. Microbial protein production offers a valid and promising alternative by upgrading low value recovered resources into high quality feed and also food. In the present study, we evaluated the potential of hydrogen-oxidizing bacteria to upgrade ammonium and carbon dioxide under autotrophic growth conditions. The enrichment of a generic microbial community and the implementation of different culture conditions (sequenced batch resp. continuous reactor) revealed surprising features. At low selection pressure (i.e. under sequenced batch culture at high solid retention time), a very diverse microbiome with an important presence of predatory Bdellovibrio spp. was observed. The microbial culture which evolved under high rate selection pressure (i.e. dilution rate D = 0.1 h(-1)) under continuous reactor conditions was dominated by Sulfuricurvum spp. and a highly stable and efficient process in terms of N and C uptake, biomass yield and volumetric productivity was attained. Under continuous culture conditions the maximum yield obtained was 0.29 g cell dry weight per gram chemical oxygen demand equivalent of hydrogen, whereas the maximum volumetric loading rate peaked 0.41 g cell dry weight per litre per hour at a protein content of 71%. Finally, the microbial protein produced was of high nutritive quality in terms of essential amino acids content and can be a suitable substitute for conventional feed sources such as fishmeal or soybean meal. PMID:27262118

  19. Autotrophic growth: the methyl binding site of CO dehydrogenase in the synthesis of acetyl-CoA

    International Nuclear Information System (INIS)

    A pathway in which CO or CO2 and H2 is used as a source of energy and carbon to synthesize acetyl-CoA is used for autotrophic growth of acetogenes, methanogens and some sulfate-reducing bacteria. All enzymes involved in this pathway have been purified from C. thermoaceticum. Five of them: CO dehydrogenase (CODH), corrinoid protein, methyltransferase, CODH disulfide reductase (SSRd) and ferredoxin catalyzed synthesis of acetyl-CoA from methyltetrahydrofolate, CO and CoA. CODH is a central enzyme catalyzing the condensation of CH3, CO and CoA and per se it catalyzes a reversible exchange of CO with acetyl-CoA. Thus, CODH must have binding sites for CH3, CO and CoA. They have succeeded in methylating β subunits of CODH using 14CH3I or 14CH-corrinoid protein, a native donor of the CH3 group in synthesis of acetyl-CoA. With resulting [14CH3]CODH, only SSRd is required for synthesis of [14C]acetyl-CoA from CO and CoA. The kinetic studies show that CH3I is a competitive inhibitor for exchange reaction between CO and acetyl-CoA. Acetaldehyde and acetyl-CoA but not acetic acid and CoA protected CODH against methylation by CH3I. Methyl group bound to CODH is very slowly removed by CO and CoA and acetyl-CoA accelerated this process. These data confirm that CH3 group from CH3I and CH3-corrinoid protein is bound to the methyl binding site of CODH

  20. Summer monsoon onset-induced changes of autotrophic pico- and nanoplankton in the largest monsoonal estuary along the west coast of India.

    Science.gov (United States)

    Mohan, Arya P; Jyothibabu, R; Jagadeesan, L; Lallu, K R; Karnan, C

    2016-02-01

    This study presents the response of autotrophic pico- and nanoplankton to southwest monsoon-associated hydrographical transformations in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. By the onset of the southwest monsoon, the euhaline/mesohaline conditions in the downstream/upstream of CBW usually transform into oligohaline/limnohaline. The flow cytometer analysis revealed the dominance of picoeukaryotes > Synechococcus > nanoautotrophs, with Prochlorococcus either very low or entirely absent. Synechococcus abundance was high during the pre-southwest monsoon (10(6) L(-1)), which dwindled with heavy fresh water influx during the southwest monsoon (10(5) L(-1)). The drastic drop in salinity and faster flushing of the CBW during the southwest monsoon replaced the euhaline/mesohaline strain of Synechococcus with an oligohaline/limnohaline strain. Epifluorescence microscopy analyses showed that, among the two strains of Synechococcus, the phycoerythrin-rich (PE-rich) one was dominant in the mesohaline/euhaline conditions, whereas the phycocyanin-rich (PC-rich) strain dominated in oligohaline/limnohaline conditions. Although Synechococcus abundance diminished during the southwest monsoon, the total abundance of picoplankton community remained virtually unchanged in the upstream due to an increase in the abundance of picoeukaryotes. On the other hand, the autotrophic nanoplankton abundance increased from pre-monsoon levels of av. 3.8 × 10(6)-av. 9.5 × 10(6) L(-1) at the onset of the southwest monsoon. Utilizing suitable multivariate analyses, the study illustrated the differential response and niche preference of various smaller communities of autotrophs to the southwest monsoon-associated hydrographical ramifications in a large monsoonal estuary, which may be applicable to similar such estuaries situated along the Indian coastline. PMID:26780412

  1. Aeration control by monitoring the microbiological activity using fuzzy logic diagnosis and control. Application to a complete autotrophic nitrogen removal reactor

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist; Sin, Gürkan

    2015-01-01

    contribution describes the development of a fuzzy-logic based system for both diagnosis and control of a CANR reactor. Based on a combination of measurements of the nitrogen species concentration in the influent and in the effluent on the one hand, and insights into the activities of three distinctive...... the reactor.The diagnosis tool was first evaluated using 100 days of real process operation data obtained from a lab-scale single-stage autotrophic nitrogen removing reactor. This evaluation revealed that the fuzzy logic diagnosis is able to provide a realistic description of the microbiological state...

  2. Autotrophic fixation of geogenic CO2 by microorganisms contributes to soil organic matter formation and alters isotope signatures in a wetland mofette

    Science.gov (United States)

    Nowak, M. E.; Beulig, F.; von Fischer, J.; Muhr, J.; Küsel, K.; Trumbore, S. E.

    2015-12-01

    To quantify the contribution of autotrophic microorganisms to organic matter (OM) formation in soils, we investigated natural CO2 vents (mofettes) situated in a wetland in northwest Bohemia (Czech Republic). Mofette soils had higher soil organic matter (SOM) concentrations than reference soils due to restricted decomposition under high CO2 levels. We used radiocarbon (Δ14C) and stable carbon (δ13C) isotope ratios to characterize SOM and its sources in two mofettes and compared it with respective reference soils, which were not influenced by geogenic CO2. The geogenic CO2 emitted at these sites is free of radiocarbon and enriched in 13C compared to atmospheric CO2. Together, these isotopic signals allow us to distinguish C fixed by plants from C fixed by autotrophic microorganisms using their differences in 13C discrimination. We can then estimate that up to 27 % of soil organic matter in the 0-10 cm layer of these soils was derived from microbially assimilated CO2. Isotope values of bulk SOM were shifted towards more positive δ13C and more negative Δ14C values in mofettes compared to reference soils, suggesting that geogenic CO2 emitted from the soil atmosphere is incorporated into SOM. To distinguish whether geogenic CO2 was fixed by plants or by CO2 assimilating microorganisms, we first used the proportional differences in radiocarbon and δ13C values to indicate the magnitude of discrimination of the stable isotopes in living plants. Deviation from this relationship was taken to indicate the presence of microbial CO2 fixation, as microbial discrimination should differ from that of plants. 13CO2-labelling experiments confirmed high activity of CO2 assimilating microbes in the top 10 cm, where δ13C values of SOM were shifted up to 2 ‰ towards more negative values. Uptake rates of microbial CO2 fixation ranged up to 1.59 ± 0.16 μg gdw-1 d-1. We inferred that the negative δ13C shift was caused by the activity of autotrophic microorganisms using the Calvin

  3. Distribution patterns and biomass estimates of diatoms and autotrophic dinoflagellates in the NE Atlantic during June and July 1996

    Science.gov (United States)

    Yallop, M. L.

    Qualitative and quantitative analyses of microphytoplankton communities were determined from samples collected in the northeast Atlantic Ocean in the early summer of 1996 during the PRIME Cruise of the RRS Discovery. A combination of light microscopy and scanning electron microscopy techniques was used to determine the species composition of two of the main groups of phytoplankton: Bacillariophyceae and Dinophyta. Two series of samples were collected; the first set of samples was collected between 18 and 29 June 1996 during a Lagrangian time-series study in the vicinity of 59°N 20°W tracking a mesoscale cold-core eddy; the second set of samples was collected between 4 and 10 July 1996 during a transect along the 20°W meridian from 59 to 37°N. A total of 155 samples were analysed over various depths down to 150 m, and 78 phytoplankton species were identified. Samples taken during the Lagrangian time-series study were dominated by diatom species, including Ephemera planamembranacea and Pseudo-nitzschia species, whilst the main representative of the microphytoplankton dinoflagellates was Ceratium fusus. On the transect, several Ceratium species were common, including C. furca C. fusus, and C. lineatum, and three other autotrophic dinoflagellates were frequent including Prorocentrum minimum, Oxytoxum scolopax and Gonyaulax polygramma. A number of diatoms dominated the profiles along the transect including Leptocylindrus mediterraneus, Thalassiosira oestrupii, and representatives of the genera Haslea and Pseudo-nitzschia. Standing stocks of both groups were low and typical of post-bloom carbon levels. Diatom biomass exceeded that of dinoflagellate biomass in the eddy although the reverse situation was seen in the more southerly stations along the transect. Maximum abundances of the dinoflagellate communities were situated in the surface waters within the mixed layer, while depth maxima of certain diatoms were noted at around 40 m below the depth of the mixed layer

  4. Large-scale demonstration of the sulfate reduction autotrophic denitrification nitrification integrated (SANI(®)) process in saline sewage treatment.

    Science.gov (United States)

    Wu, Di; Ekama, George A; Chui, Ho-Kwong; Wang, Bo; Cui, Yan-Xiang; Hao, Tian-Wei; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2016-09-01

    Recently, the Sulfate reduction Autotrophic denitrification Nitrification Integrated (SANI(®)) process was developed for the removal of organics and nitrogen with sludge minimization in the treatment of saline sewage (with a Sulfate-to-COD ratio > 0.5 mg SO4(2-)-S/mg COD) generated from seawater used for toilet flushing or salt water intrusion. Previously investigated in lab- and pilot-scale, this process has now been scaled up to a 800-1000 m(3)/d full-scale demonstration plant. In this paper, the design and operating parameters of the SANI demo plant built in Hong Kong are analyzed. After a 4-month start-up period, a stable sulfur cycle-based biological nitrogen removal system having a hydraulic retention time (HRT) of 12.5 h was developed, thereby reducing the amount of space needed by 30-40% compared with conventional activated sludge (CAS) plants in Hong Kong. The demo plant satisfactorily met the local effluent discharge limits during both the summer and winter periods. In winter (sewage temperature of 21 ± 1 °C), the maximum volumetric loading rates for organic conversion, nitrification, and denitrification were 2 kg COD/(m(3)·d), 0.39 kg N/(m(3)·d), and 0.35 kg N/(m(3)·d), respectively. The biological sludge production rate of SANI process was 0.35 ± 0.08 g TSSproduced/g BOD5 (or 0.19 ± 0.05 g TSS/g COD), which is 60-70% lower than that of the CAS process in Hong Kong. While further process optimization is possible, this study demonstrates the SANI process can be potentially implemented for the treatment of saline sewage. PMID:27232994

  5. [Abundance and Community Composition of Ammonia-Oxidizing Archaea in Two Completely Autotrophic Nitrogen Removal over Nitrite Systems].

    Science.gov (United States)

    Gao, Jing-feng; Li, Ting; Zhang, Shu-jun; Fan, Xiao-yan; Pan, Kai-ling; Ma, Qian; Yuan, Ya-lin

    2015-08-01

    Ammonia oxidation is the first and rate-limiting step of nitrification, which was thought to be only performed by ammonia-oxidizing bacteria (AOB). In recent years, ammonia-oxidizing archaea (AOA) was also confirmed to take part in ammonia oxidation. The diversity and abundance of AOA have been investigated in various environments, however, little is known regarding the AOA in the completely autotrophic nitrogen removal over nitrite (CANON) wastewater treatment process. In this study, the abundance and diversity of AOA were investigated in the biofilm and flocculent activated sludge collected in a lab-scale (L) CANON system and a pilot-scale (P) CANON systems, respectively. The quantitative real time PCR (qPCR) was applied to investigate the abundance of AOA and the diversity of AOA was determined by polymerase chain reaction (PCR), cloning and sequencing. The qPCR results showed that the average abundance of AOA amoA gene of L and P was 2.42 x 10(6) copies x g(-1) dry sludge and 6.51 x 10(6) copies x g(-1) dry sludge, respectively. The abundance of AOA in biofilm was 10.1-14.1 times higher than that in flocculent activated sludge. For P system, the abundance of AOA in flocculent activated sludge was 1.8 times higher than that in biofilm. The results indicated that the abundance of AOA might be affected by different sludge morphology. The diversity of AOA in P system was extremely limited, only one OTU was observed, which was classified into Nitrosopumilus subcluster 5.2. The diversity of AOA in L system was higher, eight OTUs were observed, which were classified into five genera: Nitrososphaera subcluster 9, subcluster 8.1, subcluster 4.1, subcluster 1.1 and Nitrosopumilus subcluster 5.2. The diversity and abundance of AOA were different in CANON systems with different sludge morphology. AOA may play an important role in ammonia oxidation in CANON system. PMID:26592025

  6. Allelopathy of Aquatic Autotrophs

    OpenAIRE

    Gross, Elisabeth

    2003-01-01

    Allelopathy in aquatic environments may provide a competitive advantage to angiosperms, algae, or cyanobacteria in their interaction with other primary producers. Allelopathy can influence the competition between different photoautotrophs for resources and change the succession of species, for exarnple, in phytoplankton cornmunities. Field evidence and laboratory studies indicate that allelopathy occurs in all aquatic habitats (marine and freshwater), and that ail prirnary producing organisms...

  7. Sequential dark-photo fermentation and autotrophic microalgal growth for high-yield and CO{sub 2}-free biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Yung-Chung [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Chen, Chun-Yen [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China); Lee, Chi-Mei [Department of Environmental Engineering, National Chung Hsing University, Taichung (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan 701 (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China); Center for Biosciences and Biotechnology, National Cheng Kung University, Tainan (China)

    2010-10-15

    Dark fermentation, photo fermentation, and autotrophic microalgae cultivation were integrated to establish a high-yield and CO{sub 2}-free biohydrogen production system by using different feedstock. Among the four carbon sources examined, sucrose was the most effective for the sequential dark (with Clostridium butyricum CGS5) and photo (with Rhodopseudomonas palutris WP3-5) fermentation process. The sequential dark-photo fermentation was stably operated for nearly 80 days, giving a maximum H{sub 2} yield of 11.61 mol H{sub 2}/mol sucrose and a H{sub 2} production rate of 673.93 ml/h/l. The biogas produced from the sequential dark-photo fermentation (containing ca. 40.0% CO{sub 2}) was directly fed into a microalga culture (Chlorella vulgaris C-C) cultivated at 30 C under 60 {mu}mol/m{sup 2}/s illumination. The CO{sub 2} produced from the fermentation processes was completely consumed during the autotrophic growth of C. vulgaris C-C, resulting in a microalgal biomass concentration of 1999 mg/l composed mainly of 48.0% protein, 23.0% carbohydrate and 12.3% lipid. (author)

  8. Production Response and Digestive Enzymatic Activity of the Pacific White Shrimp Litopenaeus vannamei (Boone, 1931 Intensively Pregrown in Microbial Heterotrophic and Autotrophic-Based Systems

    Directory of Open Access Journals (Sweden)

    Manuel J. Becerra-Dórame

    2012-01-01

    Full Text Available Shrimp postlarvae were reared into different microcosm systems without water exchange; a traditional system based on simple fertilization to improve microalgae concentration (control, an autotrophic system (AS based on the promotion of biofloc and biofilm by the addition of fertilizer and artificial substrates and a heterotrophic system (HS based on the promotion of heterotrophic bacteria by the addition of nitrogenous and carbonaceous sources and artificial substrates. Better growth performance and survival were registered in shrimp from the AS and HS compared to the control. Feed conversion ratios were below 0.7 for all treatments, but AS and HS were significantly lower than the control. Regarding digestive performance, no significant differences were observed for trypsin, amylase and lipase activities among AS and control shrimp; however, shrimp from HS showed a higher trypsin and amylase activities, suggesting a higher digestive activity caused by the presence of microbial bioflocs. The presence of biofilm and bioflocs composed by either autotrophic or heterotrophic organisms in combination with formulated feed improved the growth performance and survival of shrimp. Apparently, such combination fits the nutritional requirements of shrimp.

  9. An evidence-based framework for predicting the impact of differing autotroph-heterotroph thermal sensitivities on consumer-prey dynamics.

    Science.gov (United States)

    Yang, Zhou; Zhang, Lu; Zhu, Xuexia; Wang, Jun; Montagnes, David J S

    2016-07-01

    Increased temperature accelerates vital rates, influencing microbial population and wider ecosystem dynamics, for example, the predicted increases in cyanobacterial blooms associated with global warming. However, heterotrophic and mixotrophic protists, which are dominant grazers of microalgae, may be more thermally sensitive than autotrophs, and thus prey could be suppressed as temperature rises. Theoretical and meta-analyses have begun to address this issue, but an appropriate framework linking experimental data with theory is lacking. Using ecophysiological data to develop a novel model structure, we provide the first validation of this thermal sensitivity hypothesis: increased temperature improves the consumer's ability to control the autotrophic prey. Specifically, the model accounts for temperature effects on auto- and mixotrophs and ingestion, growth and mortality rates, using an ecologically and economically important system (cyanobacteria grazed by a mixotrophic flagellate). Once established, we show the model to be a good predictor of temperature impacts on consumer-prey dynamics by comparing simulations with microcosm observations. Then, through simulations, we indicate our conclusions remain valid, even with large changes in bottom-up factors (prey growth and carrying capacity). In conclusion, we show that rising temperature could, counterintuitively, reduce the propensity for microalgal blooms to occur and, critically, provide a novel model framework for needed, continued assessment. PMID:26684731

  10. Effects of pulsed atrazine exposures on autotrophic community structure, biomass, and production in field-based stream mesocosms.

    Science.gov (United States)

    King, Ryan S; Brain, Richard A; Back, Jeffrey A; Becker, Christopher; Wright, Moncie V; Toteu Djomte, Valerie; Scott, W Casan; Virgil, Steven R; Brooks, Bryan W; Hosmer, Alan J; Chambliss, C Kevin

    2016-03-01

    The authors performed a multiple-pulsed atrazine experiment to measure responses of autotrophic endpoints in outdoor stream mesocosms. The experiment was designed to synthetically simulate worst-case atrazine chemographs from streams in agricultural catchments to achieve 60-d mean concentrations of 0 μg/L (control), 10 μg/L, 20 μg/L, and 30 μg/L. The authors dosed triplicate streams with pulses of 0 μg/L, 50 μg/L, 100 μg/L, and 150 μg/L atrazine for 4 d, followed by 7 d without dosing. This 11-d cycle occurred 3 times, followed by a recovery (untreated) period from day 34 to day 60. Mean ± standard error 60-d atrazine concentrations were 0.07 ± 0.03 μg/L, 10.7 ± 0.05 μg/L, 20.9 ± 0.24 μg/L, and 31.0 ± 0.17 μg/L for the control, 10-μg/L, 20-μg/L, and 30-μg/L treatments, respectively. Multivariate analyses revealed that periphyton and phytoplankton community structure did not differ among treatments on any day of the experiment, including during the atrazine pulses. Control periphyton biomass in riffles was higher immediately following the peak of the first atrazine pulse and remained slightly higher than some of the atrazine treatments on most days through the peak of the last pulse. However, periphyton biomass was not different among treatments at the end of the present study. Phytoplankton biomass was not affected by atrazine. Metaphyton biomass in pools was higher in the controls near the midpoint of the present study and remained higher on most days for the remainder of the study. Ceratophyllum demersum, a submersed macrophyte, biomass was higher in controls than in 20-μg/L and 30-μg/L treatments before pulse 3 but was not different subsequent to pulse 3 through the end of the present study. Maximum daily dissolved oxygen (DO, percentage of saturation) declined during each pulse in approximate proportion to magnitude of dose but rapidly converged among treatments after the third pulse. However

  11. A survey of 16S rRNA and amoA genes related to autotrophic ammonia-oxidizing bacteria of the ß-subdivision of the class proteobacteria in contaminated groundwater

    NARCIS (Netherlands)

    Ivanova, I.A.; Stephen, J.R.; Chang, Y.J.; Bruggemann, J.; Long, P.E.; McKinley, J.P.; Kowalchuk, G.A.; White, D.C.; MacNaughton, S.J.

    2000-01-01

    In this study, we investigated the size and structure of autotrophic ammonia oxidizer (AAO) communities in the groundwater of a contamination plume originating from a mill- tailings disposal site. The site has high levels of dissolved N from anthropogenic sources, and exhibited wide variations in th

  12. Investigations on photosynthetic pigments of Lemnaceae, pt. 14: The effect of UV-B radiation on deetiolating and autotrophically growing plants of Lemna gibba L

    International Nuclear Information System (INIS)

    In deetiolating plants of Lemma gibba L., the biosynthesis of photosynthetically active pigments (chlorophyll a and b, beta-carotene, lutein, violaxanthin and neoxanthin) was reduced by UV-B radiation (2,5 W cnt * m-2) in dependence on the exposure time (8-96-h). The biosynthesis of chlorophyll b was more inhibited than that of chlorophyll a, that of the chlorophylls more than that of the carotenoids and that of beta-carotene more than that of the xanthophylls notably lutein. In autotrophic plants. UV-B radiation (42, 72 and 120 h) causes a strong reduction of the pigment content. The alteration of the ratios between the pigments was the same as in deetiolating plants. In deetiolating as well as in autotropically cultivated plants of Lemma gibba, the termination of the UV-B radiation is followed by an approach to the original ratios

  13. An operational protocol for facilitating start-up of single-stage autotrophic nitrogen-removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, Ayten Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan;

    2013-01-01

    Start-up and operation of single-stage nitritation–anammox sequencing batch reactors (SBRs) for completely autotrophic nitrogen removal can be challenging and far from trivial. In this study, a step-wise procedure is developed based on stoichiometric analysis of the process performance from...... nitrogen species measurements to systematically guide start-up and normal operation efforts (instead of trial and error). The procedure is successfully applied to laboratory-scale SBRs for start-up and maintained operation over an 8-month period. This analysis can serve as a strong decision-making tool to...... take appropriate actions with respect to reactor operation to accelerate start-up or ensure high-rate N removal via the nitritation–anammox pathway....

  14. Inmirania thermothiophila gen. nov., sp. nov., a thermophilic, facultatively autotrophic, sulfur-oxidizing gammaproteobacterium isolated from a shallow-sea hydrothermal vent.

    Science.gov (United States)

    Slobodkina, Galina B; Baslerov, Roman V; Novikov, Andrei A; Viryasov, Mikhail B; Bonch-Osmolovskaya, Elizaveta A; Slobodkin, Alexander I

    2016-02-01

    A novel thermophilic, facultatively autotrophic bacterium, strain S2479T, was isolated from a thermal spring located in a tidal zone of a geothermally heated beach (Kuril Islands, Russia). Cells of strain S2479T were rod-shaped and motile with a Gram-negative cell-wall type. The temperature range for growth was 35-68 °C (optimum 65 °C), and the pH range for growth was pH 5.5-8.8 (optimum pH 6.5). Growth of strain S2479T was observed in the presence of NaCl concentrations ranging from 0.5 to 3.5 % (w/v) (optimum 1.5-2.0 %). The strain oxidized sulfur and thiosulfate as sole energy sources for autotrophic growth under anaerobic conditions with nitrate as electron acceptor. Strain S2479T was also capable of heterotrophic growth by reduction of nitrate with oxidation of low-chain fatty acids and a limited number of other carboxylic acids or with complex proteinaceous compounds. Nitrate was reduced to N2. Sulfur compounds were oxidized to sulfate. Strain S2479T did not grow aerobically during incubation at atmospheric concentration of oxygen but was able to grow microaerobically (1 % of oxygen in gas phase). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain was a member of the family Ectothiorhodospiraceae, order Chromatiales, class Gammaproteobacteria. On the basis of phylogenetic and phenotypic properties, strain S2479T represents a novel species of a new genus, for which the name Inmirania thermothiophila gen. nov., sp. nov. is proposed. The type strain of the type species is S2479T ( = DSM 100275T = VKM B-2962T). PMID:26582356

  15. Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification.

    Science.gov (United States)

    Shin, Jung-Hun; Kim, Byung-Chun; Choi, Okkyoung; Kim, Hyunook; Sang, Byoung-In

    2015-10-28

    Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4(+)-N/m(3)/d and 0.10-0.21 kg NO3(-)-N/m(3)/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4(+) or NO3(-) loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs. PMID:26095385

  16. The effect of clay particles on the activity of suspended autotrophic nitrifying bacteria and on the performance of an air-lift reactor.

    Science.gov (United States)

    Vieira, M J; Pacheco, A P; Pinho, I A; Melo, L F

    2001-02-01

    Clay minerals have some properties, namely a high surface area and the ability of ion exchange that may exert some effects on microbial systems. It is often difficult to know the way the clay is exerting its influence and whether its presence improves a given metabolic process. The present work concerns the study of the effect of the addition of powdered kaolin to autotrophic nitrification systems, and includes the study of the effects of the particles on the activity of a suspended nitrifying bacteria consortium and on the performance of an air-lift biofilm reactor used for tertiary nitrification. Concerning the suspended culture, kaolin particles produced stimulation on the specific endogenous and exogenous respiration rates of the bacteria, probably due to a nutritional effect supplied by the clay. This effect was more pronounced for the ammonia oxidation rates, although nitrite oxidation was also enhanced but to a lesser extent. In respect to the presence of kaolin particles in the air-lift reactor, the results obtained indicate that the clay particles become incorporated in the biofilm pellets, but do not change significantly their thickness or their shape. However, nitrate production decreased when the concentration of particles increased. The low adsorption of ammonia by the kaolin indicated that the clay particles embedded in the biofilm did not probably retain the ions. Although it was not proved, precipitation of salts may have occurred. PMID:11349371

  17. An isotope approach based on C-13 pulse-chase labelling vs. the root trenching method to separate heterotrophic and autotrophic respiration in cultivated peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Biasi, C.; Pitkamaki, A. S.; Tavi, N. M.; Koponen, H. T.; Martikainen, P. J. [Univ.of Eastern Finland, Kuopio (Finland). Dept. of Environmental Science], e-mail: christina.biasi@uef.fi

    2012-11-01

    We tested an isotope method based on C-13 pulse-chase labelling for determining the fractional contribution of soil microbial respiration to overall soil respiration in an organic soil (cutaway peatland, eastern Finland), cultivated with the bioenergy crop, reed canary grass. The plants were exposed to CO{sub 2}-13 for five hours and the label was thereafter determined in CO{sub 2} derived from the soil-root system. A two-pool isotope mixing model was used to separate sources of respiration. The isotopic approach showed that a minimum of 50% of the total CO{sub 2} originated from soil-microbial respiration. Even though the method uses undisturbed soil-plant systems, it has limitations concerning the experimental determination of the true isotopic signal of all components contributing to autotrophic respiration. A trenching experiment which was comparatively conducted resulted in a 71% fractional contribution of soil-microbial respiration. This value was likely overestimated. Further studies are needed to evaluate critically the output from these two partitioning approaches. (orig.)

  18. Effect of C/N Ratio,Temperature,pH on Autotrophic Denitrification Rate with Hydrogen Gas,Iron (II) and Sodium Sulfide as Electron Donors

    Institute of Scientific and Technical Information of China (English)

    Junfeng Su; Sicheng Shao; Tinglin Huang; Fang Ma; Gang Wen; Shengchen Zheng; Kai Zhang

    2016-01-01

    Nitrate is considered to be one of the most widely present pollutants leading to eutrophication of environment. The purpose of this work was to isolate and identify new anaerobic denitrifying bacteria from reservoir sediments and utilize different electron donors for isolates to improve nitrate removal efficiency. Using traditional enrichment approach, one purified anaerobic bacterium ( Y12 ) capable of NO-3⁃N removal from sediments was obtained. The species identity of Y12 was determined via 16S rRNA gene sequence analysis to be Acinetobacter. In this work, the fastest denitrification rates were observed with ferrous iron as electron donor. And, slightly slower rates were observed with hydrogen and sodium sulfide as electron donors. However, when used hydrogen gas, ferrous iron and sodium sulfide as electron donors, C/N ratios had little effect on autotrophic denitrification rate at the initial C/N ratio from 1.5 to 9.0. Meanwhile, when made use of hydrogen gas, ferrous iron and sodium sulfide as electron donors, a maximum nitrate removal ratio of 100.00%, 91.43%and 87.99% at the temperature of 30℃, respectively. Moreover, maximum denitrification activity was observed at pH 6.0-7.0.

  19. Effect of red cyst cell inoculation and iron(II) supplementation on autotrophic astaxanthin production by Haematococcus pluvialis under outdoor summer conditions.

    Science.gov (United States)

    Hong, Min-Eui; Choi, Yoon Young; Sim, Sang Jun

    2016-01-20

    The negative effect of heat stress on the autotrophic astaxanthin production by Haematococcus pluvialis has been observed during outdoor culture in summer. Under the summer conditions, the proliferation of vegetative cells was highly halted in the green stage and the inducibility in the biosynthesis of astaxanthin was partly hindered in the red stage. Herein, under outdoor summer conditions in which variations of the diurnal temperature occur, heat-stress-driven inefficient vegetative growth of H. pluvialis was highly improved by inoculating the red cyst cells; thereby, maintaining relatively moderate intracellular carotenoid levels in the green stage. Subsequently, a remarkably enhanced astaxanthin titer was successfully obtained by supplementing 50 μM iron(II) to induce the heat stress-driven Haber-Weiss reaction in the red stage. As a result, the productivity of astaxanthin in the cells cultured under summer temperature conditions (23.4-33.5 °C) using the two methods of red cell (cyst) inoculation and the iron(Fe(2+)) supplementation was increased by 147% up to 5.53 mg/L day compared with that of the cells cultured under spring temperature conditions (17.5-27.3 °C). Our technical solutions will definitely improve the annual natural astaxanthin productivity in H. pluvialis in locations confronted by hot summer weather, particularly in large-scale closed photobioreactor systems. PMID:26630998

  20. Remediation of nitrate-nitrogen contaminated groundwater using a pilot-scale two-layer heterotrophic-autotrophic denitrification permeable reactive barrier with spongy iron/pine bark.

    Science.gov (United States)

    Huang, Guoxin; Huang, Yuanying; Hu, Hongyan; Liu, Fei; Zhang, Ying; Deng, Renwei

    2015-07-01

    A novel two-layer heterotrophic-autotrophic denitrification (HAD) permeable reactive barrier (PRB) was proposed for remediating nitrate-nitrogen contaminated groundwater in an oxygen rich environment, which has a packing structure of an upstream pine bark layer and a downstream spongy iron and river sand mixture layer. The HAD PRB involves biological deoxygenation, heterotrophic denitrification, hydrogenotrophic denitrification, and anaerobic Fe corrosion. Column and batch experiments were performed to: (1) investigate the NO3(-)-N removal and inorganic geochemistry; (2) explore the nitrogen transformation and removal mechanisms; (3) identify the hydrogenotrophic denitrification capacity; and (4) evaluate the HAD performance by comparison with other approaches. The results showed that the HAD PRB could maintain constant high NO3(-)-N removal efficiency (>91%) before 38 pore volumes (PVs) of operation (corresponding to 504d), form little or even negative NO2(-)-N during the 45 PVs, and produce low NH4(+)-N after 10 PVs. Aerobic heterotrophic bacteria played a dominant role in oxygen depletion via aerobic respiration, providing more CO2 for hydrogenotrophic denitrification. The HAD PRB significantly relied on heterotrophic denitrification. Hydrogenotrophic denitrification removed 10-20% of the initial NO3(-)-N. Effluent total organic carbon decreased from 403.44mgL(-1) at PV 1 to 9.34mgL(-1) at PV 45. Packing structure had a noticeable effect on its denitrification. PMID:25747301

  1. Comparative investigation on integrated vertical-flow biofilters applying sulfur-based and pyrite-based autotrophic denitrification for domestic wastewater treatment.

    Science.gov (United States)

    Kong, Zhe; Li, Lu; Feng, Chuanping; Dong, Shanshan; Chen, Nan

    2016-07-01

    Two parallel biofilters applying sulfur/pyrite-based autotrophic denitrification were investigated for removing COD, TP and TN by a coordinated process. Results demonstrated good performance by removing 86.32% vs 87.14% COD and 92.56% vs 89.65% NH4(+)-N. Biofilter with sulfur (BS) was superior on nitrate (89.74% vs 80.72%) and TN removal (83.18% vs 70.42%) while biofilter with pyrite (BP) was better on TP removal (82.58% vs 77.40%) and maintaining sulfate (27.56mgL(-1) vs 41.55mgL(-1)) and pH (7.13 vs 6.31). Water-permeable adsorbents lowered clogging risk and buffered loading. Clone library revealed reasons of diversities, pH variation and sulfate accumulation of both biofilters. Sulfur was efficient on denitrification but whose byproducts were troublesome, pyrite produced less byproduct but which was sensitive to organics. This research was the first attempt to systematically compare two promising alternatives and their merits/demerits for rural wastewater on-site treatment. PMID:27015019

  2. 自养硝化污泥除磷能力研究%Study on the capacity of phosphorus removal of autotrophic nitrifying sludge

    Institute of Scientific and Technical Information of China (English)

    南亚萍; 袁林江; 赵倩; 李扬扬; 王晓昌

    2011-01-01

    The phosphorus uptake by autotrophic nitrifying bacteria was studied. The nitrifying bacteria phosphorus uptake ability discussed was fed with different nutrient with ammonia, inorganic carbon and ammonia, inorganic carbon when cultured under anaerobic/aerobic condition. Results indicated that in the condition similar to EBPR of phosphate accumulating organisms, phosphorus could not be removed by the nitrifying bacteria. Cell dyeing displayed that they had no PHB granules or poly-P granules. The nitrifying bacteria had no clear phosphorus removal ability cultured in the traditional mode of phosphorus removal of phosphate accumulating bacteria. The phenomenon and the reasons caused by energy utilization,nutritional type and culture conditions were discussed.%采用静态试验对自养硝化污泥的除磷特性进行研究.分别提供氨、无机碳源和氨、无机碳源三种营养条件,考察了厌氧—好氧交替环境下硝化细菌摄取磷酸盐的情况.结果表明:在与聚磷菌的运行模式相对应的条件下,硝化污泥无除磷效果;通过染色观察,硝化细菌体内几乎没有PHB颗粒及异染颗粒;按照传统聚磷菌除磷模式培养的硝化细菌未表现出明显的除磷特性.论文从能量利用、营养类型及培养条件等方面对该现象和产生的原因进行了分析.

  3. Start-up of a completely autotrophic nitrogen removal process in a three- dimensional electrode-biofilm reactor%三维电极生物膜反应器全程自养脱氮的启动研究

    Institute of Scientific and Technical Information of China (English)

    郭劲松; 杨琳; 陈猷鹏; 方芳; 唐金晶

    2012-01-01

    A completely autotrophic nitrogen removal process was started up in a three-dimensional electrode-biofilm reactor for artificial ammonia wastewater treatment. The titanium rod coated with a thin layer of ruthenium was used as anode to generate oxygen. In the aerobic area, NH4^+-N was oxidized to NO3^- -N or NO2^- -N by nitrifying bacteria. The active carbon fiber-felt was used as cathode to generate hydrogen. And in this anaerobic area, the denitrification was completed while hydrogen was acted as the electron donor. A lot of carbon particles were filled in tbe cathode area used as three- dimensional electrode. Nitrification and denitrification process were controlled by adjusting dissolved oxygen and pH values under the condition that the initial concentration of ammonia-nitrogen was 30 mg·L^-1 , the hydraulic retention time was 24h and the temperature was 30℃. After biofilm was formed and stabilized, the removal rate of NH4^+-N and TN achieved 97.8% and 92.4% respectively. It was indicated that the completely autotrophic nitrogen removal was started up successfully. The scanning electron microscopy showed that the bacteria on surface of activated carbon fiber felt were mainly short rod-shaped Pseudomonas, while the bacteria on the surface of the activated carbon particles were Micrococcus denitrificans. They both belong to hydrogen autotrophic denitrifying bacteria. In the reactor, the stable autotrophic nitrogen system was gradually established.%采用人工配制氨氮废水,对三维电极生物膜反应器进行全程自养脱氮的启动研究.反应器中阳极采用钌涂层钛棒,在阳极区电解水产氧供硝化菌进行硝化反应;阴极采用活性炭纤维毡,并在阴极区填充活性炭颗粒构建三维电极,在阴极区电解水产氢供反硝化菌完成反硝化过程.在进水NH4^+-N浓度30mg·L^-1、温度30℃、HRT为24h的试验条件下,通过调节DO和pH实现对硝化和反硝化反应的控制.结果

  4. Analysis of cbbL, nifH, and pufLM in Soils from the Sør Rondane Mountains, Antarctica, Reveals a Large Diversity of Autotrophic and Phototrophic Bacteria.

    Science.gov (United States)

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

    2016-01-01

    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. PMID:26582318

  5. A survey of 16S rRNA and amoA genes related to autotrophic ammonia-oxidizing bacteria of the beta-subdivision of the class proteobacteria in contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, I. A.; Stephen, J. R.; Chang, Y-J.; Bruggemann, J.; Macnaughton, S. J.; White, D. C. [Tennessee Univ., Center for Environmental Biotechnology, Knoxville, TN (United States); Long, P. E.; McKinley, J. P. [Pacific Northwest National Laboratory, Richland, WA (United States); Kowalchuk, G. A. [Netherlands Inst. of Ecology, Centre for Terrestrial Ecology, Heteren (Netherlands)

    2000-11-01

    Various genetic study methods were combined to profile beta-proteobacterial ammonia-oxidizing populations in ground water extracted from the subsurface of a contamination plume resulting from the disposal of tailings from a uranium mill at Shiprock, New Mexico. The objectives of this study were to characterize the ammonia-oxidizing populations at this site in terms of the diversity of dominant ammonia-oxidizing bacteria 16S and amoA genes, and to determine whether the ground water ammonia-oxidizing populations were linked to the dissolved nitrate concentration. Several studies have suggested that the genus Nitrosospira dominates over Nitrosomonas in bulk soil environments. Ammonia-oxidizing bacterial population sizes were estimated by competitive polymerase chain reaction targeting the gene amoA; it correlated significantly with nitrate concentration. Both 16S rDNA and amoA analyses suggested that all samples were dominated by Nitrosomonas over Nitrosospira in ground water, suggesting that ground water ammonia oxidizers are more like those dominating freshwater sediments than those dominant in bulk soil. It was concluded that the failure of the Shiprock site to remediate anthropogenic nitrogen is not likely to be related to the toxic effects of uranium on autotrophic nitrification. Indeed, it is more likely to be the result of factors such as the availability of organic carbon or other electron donors. 45 refs., 1 tab., 3 figs.

  6. 生物膜内自养硝化菌与异养菌竞争关系的研究进展%Progress on Competition between Autotrophic Nitrifying Bacteria and Heterotrophic Bacteria in Biofilm

    Institute of Scientific and Technical Information of China (English)

    殷峻; 徐恒娟

    2013-01-01

    As one of efficient technologies in biological removal of organic matter and nitrogen,biofilm technology has been widely applied to the industrial and domestic wastewater treatment in the past decades.But during the practical wastewater treatment,insufficient and instable nitrogen removal often occurs.At present,many research mainly focused reactor performance,biofilm formation,hydrodynamics,mass transfer and reaction kinetics in the biofilm reactor.However,the competition between different microorganisms directly affects morphology,stability and conversion efficiency of biofilm.In this paper,the affecting factors were discussed,especially competition between autotrophic nitrifying bacteria and heterotrophic bacteria.Future issues were also proposed.%生物膜工艺作为一种高效的生物除碳脱氮技术,近20年来被广泛应用于工业废水和城市生活污水的生物处理.但在实际污水处理过程中,生物膜系统往往会出现脱氮效果不稳定的情况.目前大量的研究工作主要集中在系统的处理效率、生物膜形成、流体力学、传质以及反应动力学特性等方面.而生物膜内微生物之间的竞争关系直接影响到生物膜的形态、稳定性以及转化效率.本文针对生膜工艺及其影响因素对生物膜中自养硝化菌和异养菌竞争的研究进展进行了综述,并提出了值得进一步研究的内容.

  7. Growth of microalgae in autotrophic stationary systems

    Directory of Open Access Journals (Sweden)

    Paulo Cunha

    2008-06-01

    Full Text Available In this paper we evaluate the growth of nine marine microalgae species (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira fluviatilis and Isochrysis sp. and one freshwater species (Chlorella vulgaris under stationary autotrophy conditions, using erlenmeyers fl asks with 800mL of culture medium exposed to constant light intensities providing a photon flux density of about 150μmol.m-2.s-1 and 25±2oC temperature and constant air flow. The experiment was carried out in a controlled environment considering a block delineating randomized over time with three replicates. The Nannochloropsis oculata showed the highest value of maximum cellular density, but with a longer period of time and a lower growth rate. This was probably due to its tiny cell size, demanding a large number of cells per volume to attain its optimum conditions for light, nutrients, water and atmospheric carbon dioxide. In addition, in spite of showing one of the lowest values of maximum cellular density, Thalassiosira fluviatilis was the species that reached its maximum in a short period of time at the highest growth rate. Chlorella vulgaris was the only freshwater species tested and it showed the poorest performance for all the variables analyzed in the current study.

  8. Autotrophic Ecosystems on the Early Earth

    Science.gov (United States)

    Schulte, M.

    2003-01-01

    Ophiolite sequences, sections of lower oceanic crust and upper mantle that have been thrust onto continental craton, are located in northern and central California and provide easily accessible areas that serve as good analogs for similar, more extensive areas of the early Earth. We have begun investigating and characterizing these sites in order to understand better the processes that may be responsible for the water chemistry, mineralogy and biology of similar environments on the early Earth. The geophysical and geochemical processes in these terranes provide niches for unique communities of extremeophiles and likely provide a good analog to the location that first gave rise to life on Earth. The ophiolites found in northern and central California include the Trinity, Josephine, Coast Range and Point Sal, all of which are approximately 160 million years old. Fluids from serpentinizing springs are generally alkaline with high pH and H2 contents, indicating that the mafic rock compositions control the fluid composition through water-rock reactions during relatively low-grade hydrothermal processes. There are significant amounts of primary mineralogy remaining in the rocks, meaning that substantial alteration processes are still occurring in these terranes. The general reaction for serpentinization of olivine is given by one of the authors. olivine + H2O = serpentine + brucite + magnetite + H2. We have analyzed the mineralogical composition of several rock samples collected from the Coast Range Ophiolite near Clear Lake, CA by electron microprobe. The remnant primary mineralogy is fairly urnform in composition, with an olivine composition of Fo(sub 90), and with pyroxene compositions of En(sub 90) for orthopyroxene and En(sub 49)Wo(sub 48)Fs(sub 03) for the clinopyroxene. Other primary phases observed include chromites and other spinels. Examination of petrographic thin sections reveals that serpentinization reactions have occurred in these locations. The serpentine resulting from aqueous alteration of olivine resides in veins that are see to cross cut the primary mineral grains. There are several generations of alteration products, comprised mostly of serpentines that are magnesium rich, with magnetite, brucite and carbonates observed as accessory minerals. The formation of carbonates can be taken to indicate the presence of CO2 in the altering fluids. We collected samples from a spring in the Coast Range Ophiolite in order to determine whether the geochemical environment serves as a habitat for chemotrophic microorganisms. DNA was extracted from the sediment samples and the 16s rRNA gene was PCR amplified using universal Archaeal primers. Denaturing gradient gel electrophoresis (DGGE) was used to determine the community of Archaea thriving in these samples. Our results indicate that there were 8 different genera of Archaea from a single sample. A sequence was obtained from one of these eight. The sequence is of an organism similar to Halorubrum tibetense, and alkalophilic Archaeon. This result suggests that these environments are likely hosts for communities of organisms that are adapted for the unique chemistry provided by the alkaline spring.

  9. Mannitol in six autotrophic stramenopiles and Micromonas

    OpenAIRE

    Dittami, Simon M.; Aas, Hoai TN; Paulsen, Berit Smestad; Boyen, Catherine; Edvardsen, Bente; Tonon, Thierry

    2011-01-01

    Mannitol plays a central role in brown algal physiology since it represents an important pathway used to store photoassimilate. Several specific enzymes are directly involved in the synthesis and recycling of mannitol, altogether forming the mannitol cycle. The recent analysis of algal genomes has allowed tracing back the origin of this cycle in brown seaweeds to a horizontal gene transfer from bacteria, and furthermore suggested a subsequent transfer to the green micro-alga Micromonas. Inter...

  10. Electro-autotrophic synthesis of higher alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Liao, James C.; Cho, Kwang Myung

    2015-10-06

    The disclosure provides a process that converts CO.sub.2 to higher alcohols (e.g. isobutanol) using electricity as the energy source. This process stores electricity (e.g. from solar energy, nuclear energy, and the like) in liquid fuels that can be used as high octane number gasoline substitutes. Instead of deriving reducing power from photosynthesis, this process derives reducing power from electrically generated mediators, either H.sub.2 or formate. H.sub.2 can be derived from electrolysis of water. Formate can be generated by electrochemical reduction of CO.sub.2. After delivering the reducing power in the cell, formate becomes CO.sub.2 and recycles back. Therefore, the biological CO.sub.2 fixation process can occur in the dark.

  11. 自养条件下高氯酸盐降解细菌群落研究%The Study of the Structure of Perchlorate(ClO4-)-degrading Bacterial Communities Under Autotrophic Conditions

    Institute of Scientific and Technical Information of China (English)

    谢宇轩; 关翔宇; 于丽莎; 刘菲

    2014-01-01

    For the purpose of further investigating the biological degradation under an autotrophic condition and well understanding the microbial community structures in a complex environment, hydrogen was used as an electron donor to completely reduce perchlorate(ClO4-)in this study. The composition of microbial communities after degradation was analyzed via the construction of a cloning library by using the High-Throughput Sequencing method(HiSeq 2000). 71 days were needed to completely degrade 10 mg/L ClO4-. Microbial phylogenic analysis of HD(hydrogen degradation)after degradation indicated that the relative abundance of total bacteria in the HD was 84.96%whereas the relative abundance of Proteobacteria was 68.11%, whose percentage accounting for the total bacteria reached to 80.16%. The relative abundance of Dechloromonas which is representative in PRB was 2.7%in the HD. Simultaneously, the relative abundance of Azospira was 3.1%. KEGG was used to analyze the function of bacteria in HD. The relative abundance of genes which engaged in carbohydrate metabolism was 4.75%, and the genes included in energy metabolism was 3.35%, whereas the genes participated in nitrogen cycle was 0.72%, and the genes involving chloride transformation was 0.83%. It was demonstrated that degradation of ClO4-in a complicated condition was achieved by various kinds of microbes rather than a single one. Adding hydrogen as an electron donor to change microbial community played a role in the purification or selection process in the system, which allowed the complex systems to have the specific capacity to remove given contaminates.%旨在研究自养条件下以氢气作为电子供体高氯酸根离子(ClO4-)的微生物降解机制,利用HiSeq 2000对微生物群落结构及多样性进行高通量测序及分析。结果表明,添加氢气的HD(hydrogen degradation)体系将10 mg/L ClO4-降至检出限以下共经历71 d。ClO4-完全降解后HD体系中总细菌的相对丰度为84

  12. A first insight into the occurrence and expression of functional amoA and accA genes of autotrophic and ammonia-oxidizing bathypelagic Crenarchaeota of Tyrrhenian Sea

    Science.gov (United States)

    Yakimov, Michail M.; Cono, Violetta La; Denaro, Renata

    2009-05-01

    The autotrophic and ammonia-oxidizing crenarchaeal assemblage at offshore site located in the deep Mediterranean (Tyrrhenian Sea, depth 3000 m) water was studied by PCR amplification of the key functional genes involved in energy (ammonia mono-oxygenase alpha subunit, amoA) and central metabolism (acetyl-CoA carboxylase alpha subunit, accA). Using two recently annotated genomes of marine crenarchaeons, an initial set of primers targeting archaeal accA-like genes was designed. Approximately 300 clones were analyzed, of which 100% of amoA library and almost 70% of accA library were unambiguously related to the corresponding genes from marine Crenarchaeota. Even though the acetyl-CoA carboxylase is phylogenetically not well conserved and the remaining clones were affiliated to various bacterial acetyl-CoA/propionyl-CoA carboxylase genes, the pool of archaeal sequences was applied for development of quantitative PCR analysis of accA-like distribution using TaqMan ® methodolgy. The archaeal accA gene fragments, together with alignable gene fragments from the Sargasso Sea and North Pacific Subtropical Gyre (ALOHA Station) metagenome databases, were analyzed by multiple sequence alignment. Two accA-like sequences, found in ALOHA Station at the depth of 4000 m, formed a deeply branched clade with 64% of all archaeal Tyrrhenian clones. No close relatives for residual 36% of clones, except of those recovered from Eastern Mediterranean, was found, suggesting the existence of a specific lineage of the crenarchaeal accA genes in deep Mediterranean water. Alignment of Mediterranean amoA sequences defined four cosmopolitan phylotypes of Crenarchaeota putative ammonia mono-oxygenase subunit A gene occurring in the water sample from the 3000 m depth. Without exception all phylotypes fell into Deep Marine Group I cluster that contain the vast majority of known sequences recovered from global deep-sea environment. Remarkably, three phylotypes accounted for 91% of all Mediterranean

  13. 硫磺/石灰石自养反硝化系统脱氮除磷性能研究%Performance of Nitrogen and Phosphorus Removal of Sulfur/Limestone Autotrophic Denitrification System

    Institute of Scientific and Technical Information of China (English)

    袁玉玲; 李睿华

    2011-01-01

    In order to investigate the performance of nitrogen and phosphorus removal of the sulfur/limestone system from low C/N municipal sewage,a sulfur/limestone packed column reactor fed with synthetic wastewater,and operated in the way of anaerobic biological filter was constructed.The effects of HRT,initial concentration of phosphate,pH and temperature on nitrogen and phosphorus removal were studied.The results showed that with influent of NO-3-N 30 mg/L,PO4^3--P 15 mg/L,the optimal HRT value was 6 h,and removal rates of TN and phosphorus were 100% and 44.64% respectively.Initial concentration of phosphate and initial pH had a significant influence on nitrogen and phosphorus removal.In order to keep nitrogen removal rate higher than 90%,initial concentration of phosphate should not be below 0.4 mg/L;the optimal pH value was 6.5,and removal rates of TN and phosphorus were 91.51% and 47.68% respectively.Temperature had a positive impact on that system,the nitrogen and phosphorus removal rate decreased with decreasing temperature.The nitrate removal efficiency was high in the temperature range of 18-30℃,and the efficiency of phosphorus removal rate reached about 50%,when the temperature was between 25-30℃.The dephosphorization behavior of sulfur/limestone system correlated closely with autotrophic denitrification process,and the mechanism of phosphate removal of the SLAD system was mainly due to chemical precipitation.The system had the performance of nitrogen and phosphorus removal from low C/N municipal sewage,the highest phosphorus removal rate could reach 50%.%为了考察硫磺/石灰石系统对于低C/N的城市污水进行同步脱氮除磷的性能,设计了体积比为1∶1的硫磺/石灰石柱式反应器,以人工配水为处理对象,采用厌氧生物滤池运行方式,研究了HRT、初始磷浓度、pH、温度等因素对其脱氮除磷性能的影响.结果表明,在进水NO 3^--N为30 mg/L左右,PO4^3--P为15 mg/L条件下,系统

  14. Cell Biology of Chromerids: Autotrophic Relatives to Apicomplexan Parasites

    Czech Academy of Sciences Publication Activity Database

    Oborník, Miroslav; Lukeš, Julius

    2013-01-01

    Roč. 306, č. 2013 (2013), s. 333-369. ISSN 1937-6448 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : long-branch attraction * Plasmodium falciparum * Toxoplasma gondii * phylogenetic analysis * extrachromosomal DNA * sterol composition * ribosomal RNA * life cycle * phtotosynthetic alveolata Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.522, year: 2013

  15. Cell Biology of Chromerids: Autotrophic Relatives to Apicomplexan Parasites

    Czech Academy of Sciences Publication Activity Database

    Oborník, Miroslav; Lukeš, J.

    2013-01-01

    Roč. 306, č. 2013 (2013), s. 333-369. ISSN 1937-6448 R&D Projects: GA ČR GBP501/12/G055; GA MŠk ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : long-branch attraction * Plasmodium falciparum * Toxoplasma gondii Subject RIV: CE - Biochemistry Impact factor: 4.522, year: 2013

  16. Autotrophic and heterotrophic bacterial diversity from Yucca Mountain

    International Nuclear Information System (INIS)

    A basic understanding of the types and functions of microbiota present within the deep subsurface of Yucca Mountain will be important in terms of modeling the long term stability of a nuclear waste repository. Microorganisms can degrade building materials used in tunnel construction such as concrete and steel. For example, high concentrations of nitrifying bacteria, may cause corrosion of concrete due to the release of nitric acid. Likewise, sulfur-oxidizing and iron-oxidizing bacteria have been implicated in microbially influenced corrosion (MIC), and may contribute to the degradation of waste packages. In addition, the metabolic activities of microbiota may alter the geochemistry of surrounding environments, which may in turn influence the permeability of subsurface strata and the fate of radioactive compounds. Microorganisms that play roles in these processes have diverse methods of obtaining the energy required for growth and metabolism and have been recovered from a wide range of environments, including the deep subsurface. The purpose of this research was to determine if these bacterial groups, important to the long-term success of a high-level nuclear waste repository, were indigenous to Yucca Mountain

  17. Examining thiosulfate-driven autotrophic denitrification through respirometry.

    Science.gov (United States)

    Mora, Mabel; Guisasola, Albert; Gamisans, Xavier; Gabriel, David

    2014-10-01

    Anoxic respirometry was applied to characterize a sulfide-oxidizing nitrate-reducing (SO-NR) culture obtained from an anoxic biogas desulfurizing biotrickling filter treating high loads of H2S. Immobilized biomass extracted from the biotrickling filter was grown in a suspended culture with thiosulfate as electron donor to obtain the biomass growth yield and the S2O3(2)(-)/NO3(-) consumed ratio. Afterward, respirometry was applied to describe thiosulfate oxidation under anoxic conditions. A pure culture of Thiobacillus denitrificans was also used as a control culture in order to validate the procedure proposed in this work to characterize the SO-NR biomass. Respirometric profiles obtained with this microbial culture showed that nitrite was formed as intermediate during nitrate reduction and revealed that no competitive inhibition appeared when both electron acceptors were present in the medium. Although final bioreaction products depended on the initial S2O3(2)(-)/NO3(-) ratio, such ratio did not affect thiosulfate oxidation or denitrification rates. Moreover, respirometric profiles showed that the specific nitrite uptake rate depended on the biomass characteristics being that of a SO-NR mixed culture (39.8mgNg(-1) VSSh(-1)) higher than that obtained from a pure culture of T. denitrificans (19.7mgNg(-1) VSSh(-1)). For the first time, the stoichiometry of the two-step denitrification mechanism with thiosulfate oxidation and biomass growth associated was solved for both reactions. PMID:25065782

  18. Autotrophic and heterotrophic characteristics in a polluted tropical estuarine complex

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, Neelam; Ramaiah, N.; Chandramohan, D.; Nair, V.R.

    subtropical estuary. Applied and Environmental Microbiology 54, 718-727. Ramaiah, N. & Chandramohan, D. 1993 Ecological and laboratory studies on the role of luminous bacteria and their luminescence in coastal pollution surveillance. Marine Pollution...

  19. Autotrophic ammonia removal from landfill leachate in anaerobic membrane bioreactor.

    Science.gov (United States)

    Suneethi, S; Joseph, Kurian

    2013-01-01

    Anaerobic ammonium oxidation (ANAMMOX) process, an advanced biological nitrogen removal, removes ammonia using nitrite as the electron acceptor without oxygen. In this paper, ANAMMOX process was adopted for removing NH4+-N from landfill leachate having low COD using anaerobic membrane bioreactor (AnMBR). The AnMBR was optimized for nitrogen loading rate (NLR) varying from 0.025 to 5 kg NH4+-N/m3/d with hydraulic retention time (HRT) ranging from 1 to 3d. NH4+-N removal efficacy of 85.13 +/- 9.67% with the mean nitrogen removal rate of 5.54 +/- 0.63 kg NH4+-N/m3/d was achieved with NLR of 6.51 +/- 0.20kg NH4+-N/m3/d at 1.5 d HRT. The nitrogen transformation intermediates in the form of hydrazine (N2H4) and hydroxylamine (NH2OH) were 0.008 +/- 0.005 and 0.006 +/- 0.001 mg/l, respectively, indicating co-existence of aerobic ammonia oxidizers and ANAMMOX. The free ammonia (NH3) and free nitrous acid (HNO2) concentrations were 26.61 +/- 16.54 mg/l and (1.66 +/- 0.95) x 10(-5) mg/l, preventing NO2(-)-N oxidation to NO3(-)-N enabling sustained NH4+-N removal. PMID:24617075

  20. HYDROGEN KINETICS LIMITATION OF AN AUTOTROPHIC SULPHATE REDUCTION REACTOR

    Directory of Open Access Journals (Sweden)

    CÉSAR SÁEZ-NAVARRETE

    2012-01-01

    Full Text Available El uso de sustratos inorgánicos podría reducir los costos y simplificar la operación de sistemas de tratamiento de aguas que utilizan bacterias reductoras de sulfato. Sin embargo, el uso de H2 como sustrato energético y la bioproducción de H2S podrían provocar limitaciones cinéticas. El objetivo de este estudio fue evaluar las condiciones en las que la capacidad de transferencia de masa de un bioreactor de reducción de sulfato, limita su cinética de reducción. La cinética del reactor fue obtenida monitoreando la presión del sistema en condiciones de no limitación por sulfato. Se concluyó que el diseño del bioreactor debería basarse en sus propiedades de transferencia. La tasa de consumo de H2 alcanzó un máximo de 10-4 M/min, para una tasa de reducción de sulfato de 3.4 g·L-1·d-1. Para evitar limitación por H2 se requirió un kLa de 1.48 min-1 a 1.2·109 cells/L (1.23·10-9 L·min-1·cell-1, valor relevante para propósitos de escalamiento.

  1. 两个 CANON 污水处理系统中氨氧化古菌的丰度和多样性研究%Abundance and Community Composition of Ammonia-Oxidizing Archaea in Two Completely Autotrophic Nitrogen Removal over Nitrite Systems

    Institute of Scientific and Technical Information of China (English)

    高景峰; 李婷; 张树军; 樊晓燕; 潘凯玲; 马谦; 袁亚林

    2015-01-01

    Ammonia oxidation is the first and rate-limiting step of nitrification, which was thought to be only performed by ammonia-oxidizing bacteria (AOB). In recent years, ammonia-oxidizing archaea (AOA) was also confirmed to take part in ammonia oxidation. The diversity and abundance of AOA have been investigated in various environments, however, little is known regarding the AOA in the completely autotrophic nitrogen removal over nitrite ( CANON) wastewater treatment process. In this study, the abundance and diversity of AOA were investigated in the biofilm and flocculent activated sludge collected in a lab-scale (L) CANON system and a pilot-scale (P) CANON systems, respectively. The quantitative real time PCR (qPCR) was applied to investigate the abundance of AOA and the diversity of AOA was determined by polymerase chain reaction ( PCR), cloning and sequencing. The qPCR results showed that the average abundance of AOA amoA gene of L and P was 2. 42 × 106 copies·g - 1 dry sludge and 6. 51 × 106 copies·g - 1 dry sludge, respectively. The abundance of AOA in biofilm was 10. 1-14. 1 times higher than that in flocculent activated sludge. For P system, the abundance of AOA in flocculent activated sludge was 1. 8 times higher than that in biofilm. The results indicated that the abundance of AOA might be affected by different sludge morphology. The diversity of AOA in P system was extremely limited, only one OTU was observed, which was classified into Nitrosopumilus subcluster 5. 2. The diversity of AOA in L system was higher, eight OTUs were observed, which were classified into five genera: Nitrososphaera subcluster 9, subcluster 8. 1, subcluster 4. 1, subcluster 1. 1 and Nitrosopumilus subcluster 5. 2. The diversity and abundance of AOA were different in CANON systems with different sludge morphology. AOA may play an important role in ammonia oxidation in CANON system.%近期,氨氧化古菌(ammonia-oxidizing archaea,AOA)在各类环境中的发现,打破了人们原

  2. A novel high-throughput drip-flow system to grow autotrophic biofilms of contrasting diversities

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen;

    . Thus, thicker biofilms are likely to host greater diversity. A system with 40 replicates has been constructed using flow-through polypropylene columns housing a defined number of single-sized glass beads supported by a stainless steel mesh. Biofilms consisting primarily of ammonia oxidizing and nitrite...... oxidizing bacteria are cultivated on the beads using a drip-flow assembly by feeding a mineral medium containing ammonium-N as sole energy source. Biofilm thickness is controlled by setting the surficial loading rate to 0.168 g NH4- N/m2/day or 1.678 g NH4-N /m2/day, which should theoretically result in...

  3. Monitoring system for the study of autotrophic biofilms in bioremediation of polyaromatic compounds

    Science.gov (United States)

    Alarie, Jean P.; Bruttig, A.; Miller, Gordon H.; Hill, Walter; Vo-Dinh, Tuan

    1999-02-01

    Bacterial and other natural materials such as plants and algae have received increasing interest for bioremediation efforts. The identificatIon of materials capable of biodegrading or sequestering environmental pollutants offers an attractive alternative to chemical or physical means of remediation. A number of bacteria capable of biodegrAding organic or reducing metal pollutants have received great interest. Similarly, the use of natural plants to absorb pollutants from soil anD liquid samples is another potential approach. Our interest lies in identification of naturally occurring algae and their ability to absorb polyaromatic compounds (PAC) from groundwater sources (i.e. streams). These algae could serve as natural water filters for streams contaminated with Polyaromatic hydrocarbons. Polycyclic aromatic compounds, which comprise a complex class of condensed multi-ring benzenoid compounds, are important environmental pollutants originating from a wide variety of natural and anthropogenic sources. PACs are generally formed during incomplete combustion or pyrolysis of organic matter containing carbon and hydrogen. Because combustion of organic materials is involved in countless natural processes or human activities, PACs are omnipresent and abundant pollutants in air, soil and water. Among energy-related products, fossil fuels are the major sources of PACs. The primary sources of airborne PACs are associated with combustion, coal coking, and petroleum catalytic cracking. Coal and shale conversion also contribute to production of PACs. Production, transportation and, use of synthetic fuels and petroleum products provide emission sources for PACs. In urban environments an significant source of PACs is diesel exhaust. Food cooking and cigarette smoking activities contribute to PAC occurrence in indoor environments. Chemical analysis of PACs is of great environmental and toxicological interest because many of them have been shown to be mutagens and/or potent carcinogens in laboratory animal assays. The parent homocyclic species, which contain only carbon and hydrogen, are the familiar polyaromatic hydrocarbon (PAH) compounds. In addition to the PAH compounds, there are thousands of substituted compounds that could have various substituent groups, such as alkyl, amino, chloro, cyano, hydroxy, oxy, or thio groups. In this study we investigate anthracene and pyrene as PAH model systems. A portable fiberoptic instrument capable of real-time measurements has been developed for field screening these PAHs in surface water and natural algae systems. Our preliminary studies investigated the detection limits of anthracene and pyrene and the adsorption properties of two algae using fluorescence monitoring. An exposure study of the algae to 5 ppb anthracene was performed to investigate the ability of the algae to adsorb PAHs.

  4. Rare bacteriohopanepolyols as markers for an autotrophic, intra-aerobic methanotroph

    Science.gov (United States)

    Kool, Dorien M.; Talbot, Helen M.; Rush, Darci; Ettwig, Katharina; Sinninghe Damsté, Jaap S.

    2014-07-01

    Bacteriohopanepolyols (BHPs) and their diagenetic products, hopanoids, are of great interest for their potential as biomarker lipids in both present day environments as well as in the geological record. Specific structural features such as methylation of the A-ring, and number and type of functional groups of C35 BHPs have been held characteristic for certain groups of organisms. Here we investigated the potential presence of BHPs in the unusual anaerobic methanotroph Methylomirabilis oxyfera and another Methylomirabilis sp. Although M. oxyfera thrives in anoxic settings, it uses internally produced molecular oxygen (from nitrite) for the oxidation of methane. We found that Methylomirabilis spp. synthesizes bacteriohopanehexol (BHP-hexol), -pentol, and -tetrol, and 3-methyl derivatives of each as major BHPs. None of the C-35 amino-BHPs that are more commonly observed in methanotrophs were detected. Our findings provide the first ever account of a 3-methyl-BHP-hexol, and only the second known source organism for BHP-hexol after Alicyclobacillus acidoterrestris. As the genes required for C3-methylation seem to be exclusively present in microorganisms with an aerobic metabolism, the abundant presence of 3-methyl-BHPs in Methylomirabilis spp. denotes for the first time the potential production of 3-methyl hopanoids in anoxic environments. Furthermore, with 13C-labeling experiments we show that M. oxyfera does not assimilate methane-carbon, but rather C from bicarbonate/CO2, into its BHPs. This implies that methanotroph-derived hopanoids do not necessarily exhibit a strongly depleted carbon isotopic signature, which is commonly anticipated with methanotrophy. This may have implications for the interpretation of the presence of hopanoids and their isotopic signature in the paleorecord.

  5. Microbial community structure in autotrophic nitrifying granules characterized by experimental and simulation analyses

    DEFF Research Database (Denmark)

    Matsumoto, S.; Katoku, M.; Saeki, G.;

    2010-01-01

    the bacterial distribution obtained by fluorescence in situ hybridization analysis, as well as the measured oxygen, nitrite, nitrate and ammonium concentration profiles. Results of this study are important because they show that a combination of simulation and experimental techniques can better......This study evaluates the community structure in nitrifying granules (average diameter of 1600 mu m) produced in an aerobic reactor fed with ammonia as the sole energy source by a multivalent approach combining molecular techniques, microelectrode measurements and mathematical modelling...... groups also became evident from a 16S rRNA clone library. Microprofiles of NH4+, NO2-, NO3- and O-2 concentrations measured with microelectrodes showed good agreement with the spatial organization of nitrifying bacteria. One- and two-dimensional numerical biofilm models were constructed to explain the...

  6. Biodiesel from microalgae Chlorella protothecoides growing at autotrophic and heterotrophic metabolisms in a new symbiotic bioreactor

    OpenAIRE

    Santos, Carla A.; Reis, Alberto

    2013-01-01

    Biodiesel is an alternative energy to fossil fuels, and is produced from biomass, therefore provides lower CO2 emissions. Currently, biodiesel is produced from plant oils, animal fats and used oils. These sources are low-yield which is a limitation to the production of biodiesel in large quantities. On the contrary, microalgae present a very high yield and can be produced in large amounts. The bio-refinery of microalgae oil must have a strategy of taking advantage of all by-products to make ...

  7. A fuzzy-logic based diagnosis and control of a reactor performing complete autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist; Sin, Gürkan

    Diagnosis and control modules based on fuzzy set theory were tested for novel bioreactor monitoring and control. Two independent modules were used jointly to carry out first the diagnosis of the state of the system and then use transfer this information to control the reactor. The separation in...

  8. A fuzzy-logic based diagnosis and control of a reactor performing complete autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine; Gernaey, Krist; Sin, Gürkan

    This contribution explores the use of diagnosis and control modules based on fuzzy set theory and logic for bioreactor monitoring and control. With this aim, two independent modules were used jointly to carry out first the diagnosis of the state of the system and then use transfer this information...

  9. Effect of simulated tillage on microbial autotrophic CO2 fixation in paddy and upland soils

    Science.gov (United States)

    Ge, Tida; Wu, Xiaohong; Liu, Qiong; Zhu, Zhenke; Yuan, Hongzhao; Wang, Wei; Whiteley, A. S.; Wu, Jinshui

    2016-01-01

    Tillage is a common agricultural practice affecting soil structure and biogeochemistry. To evaluate how tillage affects soil microbial CO2 fixation, we incubated and continuously labelled samples from two paddy soils and two upland soils subjected to simulated conventional tillage (CT) and no-tillage (NT) treatments. Results showed that CO2 fixation (14C-SOC) in CT soils was significantly higher than in NT soils. We also observed a significant, soil type- and depth-dependent effect of tillage on the incorporation rates of labelled C to the labile carbon pool. Concentrations of labelled C in the carbon pool significantly decreased with soil depth, irrespective of tillage. Additionally, quantitative PCR assays revealed that for most soils, total bacteria and cbbL-carrying bacteria were less abundant in CT versus NT treatments, and tended to decrease in abundance with increasing depth. However, specific CO2 fixation activity was significantly higher in CT than in NT soils, suggesting that the abundance of cbbL-containing bacteria may not always reflect their functional activity. This study highlights the positive effect of tillage on soil microbial CO2 fixation, and the results can be readily applied to the development of sustainable agricultural management.

  10. Physiological and taxonomic description of the novel autotrophic, metal oxidizing bacterium, Pseudogulbenkiania sp. strain 2002

    OpenAIRE

    Weber, Karrie A; Hedrick, David B.; Peacock, Aaron D.; Thrash, J. Cameron; White, David C.; Achenbach, Laurie A.; Coates, John D.

    2009-01-01

    A lithoautotrophic, Fe(II) oxidizing, nitrate-reducing bacterium, strain 2002 (ATCC BAA-1479; =DSM 18807), was isolated as part of a study on nitrate-dependent Fe(II) oxidation in freshwater lake sediments. Here we provide an in-depth phenotypic and phylogenetic description of the isolate. Strain 2002 is a gram-negative, non-spore forming, motile, rod-shaped bacterium which tested positive for oxidase, catalase, and urease. Analysis of the complete 16S rRNA gene sequence placed strain 2002 in...

  11. Dynamics of various viral groups infecting autotrophic plankton in Lake Geneva

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Zhong, X.; Jacquet, S.

    , PO Box 1913, Kochi, 682018 India INRA, UMR 042 CARRTEL, 75 Avenue de Corzent, 74203 Thonon-les-Bains cx, France Corresponding author: stephan.jacquet@thonon.inra.fr ; +33 4 50 26 78 12 Abstract Viral community structure and dynamics were... groups in a same study. Moreover freshwater European ecosystems have not been investigated yet with such a battery of viral genetic markers. Lake Geneva (Léman) is the largest lake in Western Europe lying between Switzerland and France. Although...

  12. The effect of hydroxylamine on the activity and aggregate structure of autotrophic nitrifying bioreactor cultures

    DEFF Research Database (Denmark)

    Harper, W.F.; Terada, Akihiko; Poly, F.;

    2009-01-01

    by qPCR results showing that the copy numbers of amoA and nxrA genes gradually decreased by LIP to an order-of-magnitude. Longer term NH2OH addition damaged the active biomass. This research clarifies the effect of NH2OH on nitrification and demonstrates the need to incorporate NH2OH-related dynamics...

  13. Management of microbial community composition, architecture and performance in autotrophic nitrogen removing bioreactors through aeration regimes

    OpenAIRE

    Mutlu, A. Gizem; Smets, Barth F.; Sin, Gürkan

    2015-01-01

    Fuldstændig autotrof fjernelse af kvælstof (der består af delvis nitrifikation koblet med anaerob ammonium oxidation) fra spildevand med et højt kvælstof indhold kan i høj grad minimere omkostninger i form af energibesparelse sammenlignet med den konventionelle behandling af spildevand. Dette forbrug kan reduceres yderligere ved en intensivering af processen, hvor begge processer kører i samme reaktor. Dette kan lade sig gøre i systemer med biofilmdannelse eller bioaggregater, der skaber de n...

  14. Nitrification and Autotrophic Nitrifying Bacteria in a Hydrocarbon-Polluted Soil

    OpenAIRE

    Deni, Jamal; Penninckx, Michel J.

    1999-01-01

    In vitro ammonia-oxidizing bacteria are capable of oxidizing hydrocarbons incompletely. This transformation is accompanied by competitive inhibition of ammonia monooxygenase, the first key enzyme in nitrification. The effect of hydrocarbon pollution on soil nitrification was examined in situ. In a microcosm study, adding diesel fuel hydrocarbon to an uncontaminated soil (agricultural unfertilized soil) treated with ammonium sulfate dramatically reduced the amount of KCl-extractable nitrate bu...

  15. Calibration and validation of a model describing complete autotrophic nitrogen removal in a granular SBR system

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mutlu, Ayten Gizem; Gernaey, Krist;

    2013-01-01

    steady-state in the biofilm system. For oxygen mass transfer coefficient (kLa) estimation, long-term data, removal efficiencies, and the stoichiometry of the reactions were used. For the dynamic calibration a pragmatic model fitting approach was used - in this case an iterative Monte Carlo based...... screening of the parameter space proposed by Sin et al. (2008) - to find the best fit of the model to dynamic data. Finally, the calibrated model was validated with an independent data set. CONCLUSION: The presented calibration procedure is the first customized procedure for this type of system and is...

  16. Diffusive fractionation complicates isotopic partitioning of autotrophic and heterotrophic sources of soil respiration.

    Science.gov (United States)

    Moyes, Andrew B; Gaines, Sarah J; Siegwolf, Rolf T W; Bowling, David R

    2010-11-01

    Carbon isotope ratios (δ¹³C) of heterotrophic and rhizospheric sources of soil respiration under deciduous trees were evaluated over two growing seasons. Fluxes and δ¹³C of soil respiratory CO₂ on trenched and untrenched plots were calculated from closed chambers, profiles of soil CO₂ mole fraction and δ¹³C and continuous open chambers. δ¹³C of respired CO₂ and bulk carbon were measured from excised leaves and roots and sieved soil cores. Large diel variations (>5‰) in δ¹³C of soil respiration were observed when diel flux variability was large relative to average daily fluxes, independent of trenching. Soil gas transport modelling supported the conclusion that diel surface flux δ¹³C variation was driven by non-steady state gas transport effects. Active roots were associated with high summertime soil respiration rates and around 1‰ enrichment in the daily average δ¹³C of the soil surface CO₂ flux. Seasonal δ¹³C variability of about 4‰ (most enriched in summer) was observed on all plots and attributed to the heterotrophic CO₂ source. PMID:20545887

  17. Autotrophic nitrogen removal from black water: calcium addition as a requirement for settleability.

    Science.gov (United States)

    de Graaff, M S; Temmink, H; Zeeman, G; van Loosdrecht, M C M; Buisman, C J N

    2011-01-01

    Black (toilet) water contains half of the organic load in the domestic wastewater, as well as the major fraction of the nutrients nitrogen and phosphorus. When collected with vacuum toilets, the black water is 25 times more concentrated than the total domestic wastewater stream, i.e. including grey water produced by laundry, showers etc. A two-stage nitritation-anammox process was successfully employed and removed 85%-89% of total nitrogen in anaerobically treated black water. The (free) calcium concentration in black water was too low (42 mg/L) to obtain sufficient granulation of anammox biomass. The granulation and retention of the biomass was improved considerably by the addition of 39 mg/L of extra calcium. This resulted in a volumetric nitrogen removal rate of 0.5 gN/L/d, irrespective of the two temperatures of 35 °C and 25 °C at which the anammox reactors were operated. Nitrous oxide, a very strong global warming gas, was produced in situations of an incomplete anammox conversion accompanied by elevated levels of nitrite. PMID:20822793

  18. Sequentially aerated membrane biofilm reactors for autotrophic nitrogen removal: microbial community composition and dynamics

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Franck, Stephanie; Gülay, Arda;

    2014-01-01

    (rich in oxygen) and AnAOB in regions neighbouring the liquid phase. Both communities were separated by a transition region potentially populated by denitrifying heterotrophic bacteria. AOB and AnAOB bacterial groups were more abundant and diverse than NOB, and dominated by the r...... reduction of the NOB Nitrospira and Nitrobacter and a 10-fold increase in AnAOB numbers. The study of biofilm sections with relevant 16S rRNA fluorescent probes revealed strongly stratified biofilm structures fostering aerobic ammonium oxidizing bacteria (AOB) in biofilm areas close to the membrane surface......-strategists Nitrosomonas europaea and Ca. Brocadia anammoxidans, respectively. Taken together, the present work presents tools to better engineer, monitor and control the microbial communities that support robust, sustainable and efficient nitrogen removal....

  19. Autotrophic Biological Denitrification for Complete Removal of Nitrogen from Septic System Wastewater

    International Nuclear Information System (INIS)

    The overall objective of this research was to develop a reliable, robust, and maintenance-free passive system for biological denitrification in on-site wastewater treatment systems. The process relies on sulfur oxidizing denitrifying bacteria in upflow packed bioreactors. Since this process consumes alkalinity, it is necessary to add a solid-phase buffer that can scavenge the H+ as it is generated by the biologically-mediated reaction and arrest the drop in the pH value. This study investigated the use of limestone, marble chips and crushed oyster shell as solid-phase buffers that provide alkalinity.Two bench-scale upflow column reactors and two field-scale bioreactors were constructed and packed with sulfur pellets and an alkalinity source. The pilot scale bioreactors (∼200 L each) were installed at the Massachusetts Alternative Septic System Test Center (MASSTC) in Sandwich, MA. The pilot-scale bioreactors performed better when oyster shell was used as the solid-phase buffer vis-a-vis marble chips. In both (pilot-scale and laboratory-scale) systems, denitrification rates were high with the effluent NO3- -N concentration consistently below 8 mg/L

  20. Nitrate removal effectiveness of fluidized sulfur-based autotrophic denitrification biofilters for recirculating aquaculture systems

    Science.gov (United States)

    There is a need to develop practical methods to reduce nitrate -nitrogen loads from recirculating aqua-culture systems to facilitate increased food protein production simultaneously with attainment of water quality goals. The most common wastewater denitrification treatment systems utilize methanol-...

  1. Microbial communities of recirculating aquaculture facilities: interaction between heterotrophic and autotrophic bacteria and the system itself

    OpenAIRE

    Michaud, Luigi

    2007-01-01

    Les systèmes d'aquaculture en circuit recirculé (Recirculating Aquaculture Systems, RAS) peuvent être considérés comme une alternative à la technologie de l'aquaculture en milieu ouvert et en bassins (en consommant moins d'eau pour un même rendement de production) ou peuvent être intégrés dans une chaîne de production avec des systèmes d'enclos en filet. L'intérêt des RAS est dû à leurs avantages intrinsèques comme la réduction des besoins en surface et en eau, le haut niveau de contrôle e...

  2. Start-up strategies of membrane-aerated biofilm reactor (MABR) for completely autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Sun, Sheng-Peng; Pellicer i Nàcher, Carles; Terada, Akihiko;

    2009-01-01

    downside of this process stems from a long start-up period due to the slow growth rate of AnAOB. Therefore, two different start-up strategies, i.e., continuous inoculation of AnAOB and sequential batch inoculation of AOB and AnAOB, were tested in two laboratory scale membrane-aerated biofilm reactor (MABRs...

  3. Faster autotrophic growth of anaerobic ammonium-oxidizing microorganisms in presence of nitrite, using inocula from Colombia

    Directory of Open Access Journals (Sweden)

    Jaime Sanchez

    2014-06-01

    Full Text Available Título en español: Crecimiento rápido autotrófico de microorganismos anaerobios oxidadores de amonio en presencia de nitrito, usando inóculos de ColombiaShort Title: Growth from Colombian inoculated anammoxSummary: Anammox is a nitrite dependent process, catalyzed by bacteria of the order Brocadiales. Anammox bacteria oxidize ammonia under anoxic conditions, with nitrite as electron acceptor producing dinitrogen gas. Here, we demonstrated the presence of anammox bacteria by enriched them in a SBR reactor, with anaerobic samples taken from de bottom of a pond used in primary wastewater treatment. The enrichment reached nitrogen (N removal rates of nearly 1.92kg N/m3/day. (The stoichiometry of the reaction matched previous anammox studies. The enriched bacterial communities were analyzed by Fluorescence In situ Hybridization (FISH, and showed nearly a 90% of enrichment at the end of the experiment (day 90. As far as we know, this is the first time that the anammox bacteria were enriched using Colombian inocula. The enrichment was achieved in relatively short time with high yields and has an excellent potential for application in wastewater treatment opening the opportunity to treat nitrogen-rich effluents by partial nitritation and anammox, thereby decreasing operational costs with respect to aeration (nitrification and addition of organic electron donor (heterotrophic denitrification. This more sustainable treatment is a good alternative to control nutrient pollution in water bodies in tropical countries.Key words: nitrogen cycle; advanced treatment; anammox;  nitritation; nitratation; denitrification.Resumen: La oxidación anaerobia del amonio (anammox, es un proceso nitrito dependiente, catalizado por bacterias del filo planctomicetes. Estas bacterias oxidan el amonio en ausencia de oxígeno, con nitrito como aceptor de electrones produciendo nitrógeno molecular. En Colombia, demostramos la presencia de estas bacterias mediante el enriquecimiento de cultivos en reactores por lotes, con inóculos nativos, provenientes de muestras anaeróbias tomadas del fondo de una laguna para el tratamiento primario de aguas residuales. El enriquecimiento logrado alcanzó remociones de nitrógeno (N, en el orden de 1.92kg - N /m3/día (la estequiometria de la reacción estuvo acorde con estudios previos de anammox. La comunidad bacteriana enriquecida, se analizó mediante hibridación en sitio con fluorescencia (FISH, y mostró que el enriquecimiento contenía aprox. 90 % de bacterias anammox al final del experimento (Día 90. Esta es la primera vez que en Colombia se logra el enriquecimiento de estas bacterias con inóculos locales, hasta nuestro conocimiento. El enriquecimiento fue alcanzado en relativamente corto tiempo con altos rendimientos y tiene un excelente potencial de aplicación en el tratamiento de aguas residuales, abriendo oportunidades para el tratamiento de efluentes ricos en nitrógeno mediante nitritación parcial y anammox, disminuyendo los costos en los procesos de aireación (nitrificación y en la de adición de donadores orgánicos (denitrificación heterótrofa. El uso de estos tratamientos más sostenibles es una buena alternativa para el control de contaminación por nutrientes en los cuerpos de agua, en países tropicales.Palabras clave: Ciclo del Nitrógeno; Tratamiento avanzado;  anammox; nitritación; nitratación; denitrificación.

  4. Autotrophic and heterotrophic abundance and activity associated with a nearshore front off the Georgia coast, U.S.A.

    Science.gov (United States)

    Jacobsen, T. R.; Pomeroy, L. R.; Blanton, J. O.

    1983-11-01

    The nearshore frontal zone off the coast of Georgia was found to be an area of high phytoplankton and bacterioplankton abundance and activity. Phytoplankton and bacterioplankton populations on the seaward side of the frontal zone had significantly higher photosynthetic and heterotrophic potentials than the nearshore side of the front. Phytoplankton species composition changed across the front, verifying that the front is a barrier to cross shelf mixing. Nearshore, large chain forming diatoms dominated, while smaller single cell diatoms and cyanobacteria dominated the seaward side of the front. Increased bacterioplankton activity was found associated with phytoplankton photosynthetic activity. Light appeared to be the major factor controlling photosynthesis across the frontal zone. Nitrogen, phosphorus and silica were present in similar concentrations, well above levels that would limit photosynthesis, on both sides of the front. Therefore the outflow of nutrients from rivers or estuaries did not influence primary production directly.

  5. Cultivation of Autotrophic Ammonia-Oxidizing Archaea from Marine Sediments in Coculture with Sulfur-Oxidizing Bacteria▿ †

    OpenAIRE

    Park, Byoung-Joon; Park, Soo-Je; Yoon, Dae-No; Schouten, Stefan; Sinninghe Damsté, Jaap S.; Rhee, Sung-Keun

    2010-01-01

    The role of ammonia-oxidizing archaea (AOA) in nitrogen cycling in marine sediments remains poorly characterized. In this study, we enriched and characterized AOA from marine sediments. Group I.1a crenarchaea closely related to those identified in marine sediments and “Candidatus Nitrosopumilus maritimus” (99.1 and 94.9% 16S rRNA and amoA gene sequence identities to the latter, respectively) were substantially enriched by coculture with sulfur-oxidizing bacteria (SOB). The selective enrichmen...

  6. Characterization of a model cyanobacterium Synechocystis sp. PCC 6803 autotrophic growth in a flat-panel photobioreactor

    Czech Academy of Sciences Publication Activity Database

    Zavřel, T.; Sinětova, M. A.; Búzová, Diana; Literáková, Petra; Červený, Jan

    2015-01-01

    Roč. 15, č. 1 (2015), s. 122-132. ISSN 1618-0240 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) EE2.3.20.0256 Institutional support: RVO:67179843 Keywords : Carbon dioxide * Exponential phase * Growth optimization * Light * Temperature Subject RIV: EH - Ecology, Behaviour Impact factor: 2.485, year: 2014

  7. Performance and microbial communities of Mn(II)-based autotrophic denitrification in a Moving Bed Biofilm Reactor (MBBR).

    Science.gov (United States)

    Su, Jun Feng; Luo, Xian Xin; Wei, Li; Ma, Fang; Zheng, Sheng Chen; Shao, Si Cheng

    2016-07-01

    In this study, Mn(II) as electron donor was tested for the effects on denitrification in the MBBR under the conditions of initial nitrate concentration (10mgL(-1), 30mgL(-1), 50mgL(-1)), pH (5, 6, 7) and hydraulic retention time (HRT) (4h, 8h, 12h) which conducted by response surface methodology (RSM), the results demonstrated that the highest nitrate removal efficiency was occurred under the conditions of initial nitrate concentration of 47.64mgL(-1), HRT of 11.96h and pH 5.21. Analysis of SEM and flow cytometry suggested that microorganisms were immobilized on the Yu Long plastic carrier media successfully before the reactor began to operate. Furthermore, high-throughput sequencing was employed to characterize and compare the community compositions and structures of MBBR under the optimum conditions, the results showed that Pseudomonas sp. SZF15 was the dominant contributor for effective removal of nitrate in the MBBR. PMID:27061262

  8. pH variation and influence in an autotrophic nitrogen removing biofilm system using an efficient numerical solution strategy

    OpenAIRE

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Valverde Perez, Borja; Gernaey, Krist; Sin, Gürkan

    2013-01-01

    A pH simulator consisting of an efficient numerical solver of a system of nine nonlinear equations was constructed and implemented in the modeling software MATLAB. The pH simulator was integrated in a granular biofilm model and used to simulate the pH profiles within granules performing the nitritation-anammox process for a range of operating points. The simulation results showed that pH profiles were consistently increasing with increasing depth into the granule, since the proton producing a...

  9. Characterization of an Autotrophic Nitrogen-Removing Biofilm from a Highly Loaded Lab-Scale Rotating Biological Contactor

    OpenAIRE

    Pynaert, Kris; Smets, Barth F.; Wyffels, Stijn; Beheydt, Daan; Siciliano, Steven D.; Verstraete, Willy

    2003-01-01

    In this study, a lab-scale rotating biological contactor (RBC) treating a synthetic NH4+ wastewater devoid of organic carbon and showing high N losses was examined for several important physiological and microbial characteristics. The RBC biofilm removed 89% ± 5% of the influent N at the highest surface load of approximately 8.3 g of N m−2 day−1, with N2 as the main end product. In batch tests, the RBC biomass showed good aerobic and anoxic ammonium oxidation (147.8 ± 7.6 and 76.5 ± 6.4 mg of...

  10. Dynamics of Endogenous Cytokinins during the Growth Cycle of a Hormone-Autotrophic Genetic Tumor Line of Tobacco

    Science.gov (United States)

    Nandi, Shyamal K.; Palni, Lok Man S.; Parker, Charles W.

    1990-01-01

    The profile of endogenous cytokinins in a genetic tumor line of tobacco, namely, Nicotiana glauca (Grah.) × Nicotiana langsdorffii (Weinm.), following 1 to 10 weeks of growth on solid medium was determined by radioimmunoassay. 3H-labeled cytokinins of high specific activity were added during tissue extraction to correct for the purification losses. Following subculture (of 4-week-old tissues when their cytokinin content is high) onto fresh medium the total cytokinin content continued to be high during the first week (1470 picomoles per gram fresh weight) when the tissue fresh weight remained essentially unchanged (lag phase). The cytokinin levels then declined by about half in 2- and 3-week-old tissues (626 and 675 picomoles per gram fresh weight, respectively), a period when rapid increase in tissue fresh weight was recorded. Increments of 840% and 2780% over initial fresh weight were obtained in 2- and 3-week-old cultures, respectively. The cytokinin content then increased to initial high levels in 4-week-old tissues (1384 picomoles per gram fresh weight) after which it gradually declined with tissue age. The lowest cytokinin levels (432 picomoles per gram fresh weight) were observed in 10-week-old tissues. Maximal tissue fresh weight (4030% increase over initial fresh weight) was recorded in 5-week-old cultures after which it decreased slowly to 77.5% of the highest tissue fresh weight in 10-week-old cultures. Zeatin appeared to be the dominant endogenous cytokinin in tissues of all ages. Other cytokinins quantified were dihydrozeatin, zeatin riboside, and dihydrozeatin riboside; the values may include contributions from aglucones derived from the hydrolysis of corresponding O-glucosides, since the entire basic fraction was treated with β-glucosidase before analysis. In addition the levels of isopentenyladenine, isopentenyladenosine, and the nucleotides of zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine were also determined. PMID:16667800

  11. Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

    Czech Academy of Sciences Publication Activity Database

    González-Toril, E.; Amils, R.; Delmas, R.J.; Petit, J.-L.; Komárek, Jiří; Elster, Josef

    2009-01-01

    Roč. 6, č. 1 (2009), s. 33-44. ISSN 1726-4170 R&D Projects: GA MŠk ME 934; GA MŠk ME 945; GA ČR GA206/05/0253 Institutional research plan: CEZ:AV0Z60050516 Keywords : bacteria * glacial ecosytems * polar and high mountains habitats Subject RIV: EF - Botanics Impact factor: 3.246, year: 2009

  12. Methanogenesis as a potential source of chemical energy for primary biomass production by autotrophic organisms in hydrothermal systems on Europa

    Science.gov (United States)

    McCollom, Thomas M.

    Geochemical models are used to explore the possibility that lithoautotrophic methanogenesis (the conversion of CO2 plus H2 to methane) could be a source of metabolically useful chemical energy for the production of biomass at putative European hydrothermal systems. Two cases are explored: a relatively reduced methane-rich ocean and a relatively oxidized sulfate-and bicarbonate-rich ocean. In the case of a methane-rich ocean, a source of CO2 for methanogenesis is provided by conversion of dissolved methane to CO2 during reaction of ocean water with igneous rocks at high temperatures in the subsurface. Fluid-rock reactions also provide a source of dissolved H2 in the hydrothermal fluid. When this fluid circulates back to the ocean floor and mixes with seawater, conversion of the dissolved CO2 and H2 to methane provides a potential source of chemical energy that can be used to drive metabolic processes. For the case of a sulfate- and carbonate-rich ocean, reaction with reduced igneous rocks at high temperatures will also produce hydrothermal fluids with high H2 concentrations (as occurs in hydrothermal systems on Earth). Mixing of the resulting hydrothermal fluid with seawater in a relatively oxidized ocean could supply energy from either methanogenesis or sulfate reduction. For plausible compositions of a European ocean, methanogenesis can supply similar amounts of energy to that which supports the prolific ecosystems surrounding submarine hydrothermal vents on Earth. Even in the most optimistic case, however, the total amount of biomass that could be supported globally by lithoautotrophic microbes on Europa is extremely small compared to the biomass produced photosynthetically on Earth. Nevertheless, sufficient metabolic energy could apparently be available at hydrothermal systems on Europa to support an origin of life and localized ecosystems.

  13. pH variation and influence in an autotrophic nitrogen removing biofilm system using an efficient numerical solution strategy

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Valverde Perez, Borja; Gernaey, Krist; Sin, Gürkan

    2013-01-01

    nitritation-anammox process for a range of operating points. The simulation results showed that pH profiles were consistently increasing with increasing depth into the granule, since the proton producing aerobic ammonium oxidizers (AOB) were located close to the granule surface.Despite this pH profile, more...

  14. Algal Lipids and Omega-3 Production via Autotrophic and Heterotrophic Pathways at Cellana?s Kona Demonstration Facility, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xuemei [Cellana LLC; Knurek, Emily [Cellana LLC; Goes, Nikki [Cellana LLC; Griswold, Lynn [Cellana LLC

    2012-05-05

    Cellana?s Kona Demonstration Facility (KDF) is a 2.5 hectare facility, with 17,000 sq. ft. under roof and 1 hectare of cultivation systems. KDF is designed to execute and support all stages of the production process at pilot scale, from cultivation through extraction. Since Feb. 2009, KDF has been producing up to 0.7MT dry weight of algal biomass per month, while at the same time optimizing processes of cultivation, harvesting, dewatering and extraction. The cultivation system at KDF uses ALDUO? technology, a hybrid system of photobioreactors (PBRs) and open ponds. All fluid transfers related to KDF cultivation and harvesting processes are operated and monitored by a remote Process-Control System. Fluid transfer data, together with biochemical data, enable the mass balance calculations necessary to measure productivity. This poster summarizes methods to improve both biomass and lipids yield by 1) alleviating light limitation in open ponds, 2) de-oxygenation and 3) heterotrophic lipid production for post-harvesting cultures.

  15. Anaerobic Removal of Ammonia Nitrogen by an Autotrophic Reactor with Fixed Film Opering in a Sequential Batch

    OpenAIRE

    Murilo C. Lucas; José H. A. Vasconcelos; Francisco Javier Cuba Téran; Carla Eloísa Diniz dos Santos

    2010-01-01

    This study presents results of ammonia nitrogen oxidation in absence of molecular oxygen. They were obtained after the operation of a sequential batch anaerobic reactor with fixed film. After the inoculation with sludge from an anaerobic stabilization pond of a slaughterhouse wastewater treatment plant, the reactor was fed with a synthetic culture media, as described by Martins (2007), in order to establish ideal conditions for growth and development of Anammox culture. The duration of the ba...

  16. Autotrophic component of soil respiration is repressed by drought more than the heterotrophic one in a dry grassland

    Science.gov (United States)

    Balogh, J.; Papp, M.; Pintér, K.; Fóti, Sz.; Posta, K.; Eugster, W.; Nagy, Z.

    2015-10-01

    Summer droughts projected to increase in Central Europe due to climate change strongly influence the carbon cycle of ecosystems. Persistent respiration activities during drought periods are responsible for a significant carbon loss, which may turn the ecosystem from sink to source of carbon. There are still gaps in our knowledge regarding the characteristic changes taking place in the respiration of the different components of the ecosystem respiration in response to drought events. Here, we combined a physical separation of soil respiration components with continuous measurements of soil CO2 efflux and its isotopic (13C) signal at a dry grassland site in Hungary. The physical separation of soil respiration components was achieved by the use of inox meshes and tubes inserted into the soil. The root-excluded and root- and mycorrhiza-excluded treatments served to measure the isotopic signal of the rhizospheric, mycorrhizal fungi and heterotrophic components, respectively. In the dry grassland investigated in this study the three components of the soil CO2 efflux decreased at different rates under drought conditions. During drought the contribution made by the heterotrophic components was the highest. Rhizospheric component was the most sensitive to soil drying with its relative contribution to the total soil respiration dropping from 71 ± 4 % (non-stressed) to 36 ± 12 % under drought conditions. According to our results, the heterotrophic component of soil respiration is the major contributor to the respiration activities during drought events.

  17. Seasonal dynamics of autotrophic and heterotrophic plankton metabolism and PCO2 in a subarctic Greenland fjord

    DEFF Research Database (Denmark)

    Sejr, Mikael K.; Krause-Jensen, Dorte; Dalsgaard, Tage;

    2014-01-01

    We measured net planktonic community production (NCP), community respiration (CR), and gross primary production (GPP) in September, February, and May in a subarctic Greenland fjord influenced by glacial meltwater and terrestrial runoff. Potential controls of pelagic carbon cycling, including the ...

  18. RNA-seq-based comparative transcriptome analysis of the syngas-utilizing bacterium Clostridium ljungdahlii DSM 13528 grown autotrophically and heterotrophically.

    Science.gov (United States)

    Tan, Yang; Liu, Juanjuan; Chen, Xiaohua; Zheng, Huajun; Li, Fuli

    2013-11-01

    Clostridium ljungdahlii DSM 13528 represents a promising platform organism for production of a whole variety of different biofuels and biochemicals from syngas. Although the publication of its genome gave us the first possibility to understand the molecular mechanism for carbon utilization, reports on the profiling of the transcriptome were unavailable. In this study, RNA-seq-based global transcriptome analysis was performed to compare the transcriptomes of C. ljungdahlii grown on CO-CO2 with those grown on fructose. In total, 1852 differentially expressed genes were identified, which included 366 upregulated genes and 1486 downregulated genes under CO-CO2 conditions. These up- and downregulated genes are predicted to be involved in the Wood-Ljungdahl pathway, CO2 reduction to acetic acid, fructose fermentation, central carbon metabolism and transport, and vitamin B12 synthesis. In addition, 36 small RNAs were identified, 20 of which were novel small RNAs. Quantitative real-time PCR (qRT-PCR) and RT-PCR analysis of the selected functional genes and sRNA genes expression profiles were found to be consistent with the RNA-seq data. The study allowed a deeper understanding of the molecular mechanisms underlying syngas utilization and could help guide the design of rational strategies to increase the efficiency of syngas fixation in the future. PMID:24056499

  19. Enrichment and Characterization of an Autotrophic Ammonia-Oxidizing Archaeon of Mesophilic Crenarchaeal Group I.1a from an Agricultural Soil

    NARCIS (Netherlands)

    Jung, M.Y.; Park, S.J.; Min, D.; Kim, J.S.; Rijpstra, W.I.C.; Sinninghe Damsté, J.S.; Kim, G.J.; Madsen, E.L.; Rhee, S.K.

    2011-01-01

    Soil nitrification is an important process for agricultural productivity and environmental pollution. Though one cultivated representative of ammonia-oxidizing Archaea from soil has been described, additional representatives warrant characterization. We describe an ammonia-oxidizing archaeon (strain

  20. Antifungal activity of extracts from endophytic fungi associated with Smallanthus maintained in vitro as autotrophic cultures and as pot plants in the greenhouse

    Science.gov (United States)

    Fungal endophytes associated with leaves, lateral shoots, and roots of Echinacea purpurea, a medicinal plant used by Native Americans, were evaluated for antifungal activity as well as larvicidal, adulticidal, and repellent activities against Aedes aegypti. A total of 39 fungal isolates were identif...

  1. To clone the ammonia monooxygenase gene of autotrophic bacteria ammonium oxidation capacity%化能自养菌氨单加氧酶基因的克隆

    Institute of Scientific and Technical Information of China (English)

    龚国利; 张甜; 史政豪; 魏选明; 王磊

    2015-01-01

    氨氧化细菌是一类革兰氏阴性的化能自养菌.也是生物脱氮工艺中不可缺少的一类细菌.本研究通过以土壤为材料富集氨氧化细菌,并从富集土样的全基因组中成功扩增到amoA全长基因,与NCBI标准菌株 Nitrosomonas sp .GH22序列同源性达到99%,并用amoA 全长基因构建得克隆载体,经菌落PC R和双酶切鉴定正确,为后期构建新型的生物脱氮基因工程菌奠定基础.%Ammonia oxidizing bacteria is a class of gram negative chemoautotrophic bacteria , and it is also a kind of indispensable in the process of biological removal of nitrogen .In this study ,the amoA gene was successfully amplified from the whole genome of the enriched soil sample ,then put this amoA gene sequence blasted in Genbank through Internet online;at last ,we get a result that it has high homology with the amoA gene of Nitrosomonas sp . GH22(99% ) .According to the amoA full‐length gene constructed a cloned vector ,through the identification of colony PCR and restriction analysis were correct ,to lay the foundation for the later construction of a new biological nitrogen removal genetically engineered bacteri‐a.

  2. Dynamics of endogenous cytokinins during the growth cycle of a hormone-autotrophic genetic tumor line of tobacco. [Nicotiana glauca (Grah. )

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, S.K.; Palni, L.M.S.; Parker, C.W. (Australian National Univ., Canberra (Australia))

    1990-11-01

    The profile of endogenous cytokinins in a genetic tumor line of tobacco, namely, Nicotiana glauca (Grah.) x Nicotiana langsdorffii (Weinm.), following 1 to 10 weeks of growth on solid medium was determined by radioimmunoassay. {sup 3}H-labeled cytokinins of high specific activity were added during tissue extraction to correct for the purification losses. Following subculture (of 4-week-old tissues when their cytokinin content is high) onto fresh medium the total cytokinin content continued to be high during the first week (1,470 picomoles per gram fresh weight) when the tissue fresh weight remained essentially unchanged (lag phase). The cytokinin levels then declined by about half in 2- and 3-week-old tissues (626 and 675 picomoles per gram fresh weight, respectively), a period when rapid increase in tissue fresh weight was recorded. Increments of 840% and 2,780% over initial fresh weight were obtained in 2- and 3-week-old cultures, respectively. The cytokinin content then increased to initial high levels in 4-week-old tissues (1,384 picomoles per gram fresh weight) after which it gradually declined with tissue age. The lowest cytokinin levels (432 picomoles per gram fresh weight) were observed in 10-week-old tissues. Maximal tissue fresh weight (4,030% increase over initial fresh weight) was recorded in 5-week-old cultures after which it decreased slowly to 77.5% of the highest tissue fresh weight in 10-week-old cultures. Zeatin appeared to be the dominant endogenous cytokinin in tissues of all ages. Other cytokinins quantified were dihydrozeatin, zeatin riboside, and dihydrozeatin riboside; the values may include contributions from aglucones derived from the hydrolysis of corresponding O-glucosides, since the entire basic fraction was treated with {beta}-glucosidase before analysis.

  3. Amplification of 16S ribosomal RNA genes of autotrophic ammonia-oxidizing bacteria demonstrates the ubiquity of nitrosospiras in the environment.

    Science.gov (United States)

    Hiorns, W D; Hastings, R C; Head, I M; McCarthy, A J; Saunders, J R; Pickup, R W; Hall, G H

    1995-11-01

    Oligonucleotide sequences selected from the 16S rRNA genes of various species of ammonia-oxidizing bacteria were evaluated as specific PCR amplification primers and probes. The specificities of primer pairs for eubacterial, Nitrosospira and Nitrosomonas rRNA genes were established with sequence databases, and the primer pairs were used to amplify DNA from laboratory cultures and environmental samples. Eubacterial rRNA genes amplified from samples of soil and activated sludge hybridized with an oligonucleotide probe specific for Nitrosospira spp., but not with a Nitrosomonas-specific probe. Lakewater and sediment samples were analysed using a nested PCR technique in which eubacterial rRNA genes were subjected to a secondary amplification with Nitrosomonas or Nitrosospira specific primers. Again, the presence of Nitrosospira DNA, but not Nitrosomonas DNA, was detected and this was confirmed by hybridization of the amplified DNA with an internal oligonucleotide probe. Enrichments of lakewater and sediment samples, incubated for two weeks in the presence of ammonium, produced nitrite and were found to contain DNA from both Nitrosospira and Nitrosomonas as determined by nested PCR amplification and probing of 16S rRNA genes. This demonstrates that Nitrosospira spp. are widespread in the environment. The implications of the detection of Nitrosomonas DNA only after enrichment culture are discussed. PMID:8535507

  4. Impacto del pastoreo sobre picoplancton autotrófico en dos lagos andinos (Patagonia, Argentina) con diferentes relaciones luz:nutrientes Grazing impact on autotrophic picoplankton in two south Andean lakes (Patagonia, Argentina) with different light:nutrient ratios

    OpenAIRE

    ESTEBAN G BALSEIRO; CLAUDIA P. QUEIMALIÑOS; BEATRIZ E. MODENUTTI

    2004-01-01

    Los lagos andino-patagónicos son ambientes con una alta relación luz:nutrientes. En estos lagos se ha descrito una red trófica particular constituida por grandes ciliados mixotróficos que comparten y compiten por recursos alimentarios con nanoflagelados y cladóceros. A través de experimentos de pastoreo se compararon las tasas de limpieza sobre picoplancton autotrófico de nanoflagelados; el ciliado Ophrydium naumanni y cladóceros de los lagos Moreno Oeste y Rivadavia. Estos lagos presentan di...

  5. 基于氨单加氧酶基因的自养脱氮菌群结构分析%Phylogenetic Analysis based on the amoA Gene of Ammonia Oxidizers in an Autotrophic Nitrogen-Removal Reactor

    Institute of Scientific and Technical Information of China (English)

    郑雪松; 龚钢明

    2009-01-01

    全程自养脱氮是一种在高氨氮低溶氧条件下完全由自养菌群作用脱除氮素的现象.以全程自养脱氮污泥为研究对象,特异性扩增氨单加氧酶活性基因amoA片段,建立克隆文库并对克隆序列进行系统发育学分析,考察全程自养脱氮系统从建立到退化过程中氨氧化菌的结构变迁.结果表明:Nitrosomonas oligotropha和Nitrosomonas europaea细菌是系统中的主要氨氧化菌,而随着系统的退化前者逐渐被后者完全取代,而氨氧化菌的种群变迁可能并不是全混流系统全程自养脱氮效率下降的原因.

  6. Community context mediates the top-down vs. bottom-up effects of grazers on rocky shores

    OpenAIRE

    Bracken, MES; Dolecal, RE; Long, JD

    2014-01-01

    Interactions between grazers and autotrophs are complex, including both topdown consumptive and bottom-up facilitative effects of grazers. Thus, in addition to consuming autotrophs, herbivores can also enhance autotroph biomass by recycling limiting nutrients, thereby increasing nutrient availability. Here, we evaluated these consumptive and facilitative interactions between snails (Littorina littorea) and seaweeds (Fucus vesiculosus and Ulva lactuca) on a rocky shore. We partitioned herbivor...

  7. An autotrophic H 2 -oxidizing, nitrate-respiring, Tc(VII)-reducing A cidovorax sp. isolated from a subsurface oxic-anoxic transition zone: H 2 -oxidizing, Tc-reducing Acidovorax spp.

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji-Hoon [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fredrickson, James K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Plymale, Andrew E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dohnalkova, Alice C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Resch, Charles T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McKinley, James P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shi, Liang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-08

    Increasing concentrations of H2 with depth were observed across a geologic unconformity and associated redox transition zone in the subsurface at the Hanford Site in south-central Washington, USA. An opposing gradient characterized by decreasing O2 and nitrate concentrations was consistent with microbial-catalyzed biogeochemical processes. Sterile sand was incubated in situ within a multi-level sampler placed across the redox transition zone to evaluate the potential for Tc(VII) reduction and for enrichment of H2-oxidizing denitrifiers capable of reducing Tc(VII). H2-driven TcO4- reduction was detected in sand incubated at all depths but was strongest in material from a depth of 17.1 m. Acidovorax spp. were isolated from H2-nitrate enrichments from colonized sand from 15.1 m, with one representative, strain JHL-9, subsequently characterized. JHL-9 grew on acetate with either O2 or nitrate as electron acceptor (data not shown) and on medium with bicarbonate, H2 and nitrate. JHL-9 also reduced pertechnetate (TcO4-) under denitrifying conditions with H2 as the electron donor. H2-oxidizing Acidovorax spp. in the subsurface at Hanford and other locations may contribute to the maintenance of subsurface redox gradients and offer the potential for Tc(VII) reduction.

  8. Mixotrophs in aquatic ecosystems : linking physiology to food web dynamics

    OpenAIRE

    Wilken, S.

    2013-01-01

    Mixotrophs combine traits from plants (autotrophs) and animals (heterotrophs. They can use sunlight for photosynthesis but also feed on other organisms. Understanding the intricate interaction and regulation of these autotrophic and heterotrophic processes within mixotrophs is essential for understanding their functional role in ecosystem processes, including their potential application as biological control agents against toxic cyanobacteria. This thesis combines lab experiments with mathema...

  9. Nobel Prize winners for literature as palliative for scientific English.

    Science.gov (United States)

    Sri Kantha, Sachi

    2003-02-01

    Plagiarism causes a serious concern in scientific literature. I distinguish two types of plagiarism. What is routinely highlighted and discussed is the reprehensible type of stealing another author's ideas and words. This type I categorize as "heterotrophic" plagiarism. A more prevalent and less-discussed type of plagiarism is the verbatim use of same sentences repetitively by authors in their publications. This I categorize as "autotrophic" plagiarism. Though harmless per se, autotrophic plagiarism is equally taxing on the readers. The occurrence of autotrophic plagiarism is mainly caused by the lack of proficiency in the current lingua franca of science, ie, English. The writings of 22 Nobel literature laureates who wrote in English, especially their travelogues, essays, and letters to the press can be used for benefit of improving one's own vocabulary and writing skills and style. I suggest the writings of three literati--Bernard Shaw, Bertrand Russell, and Ernest Hemingway--as palliatives for autotrophic plagiarism in scientific publishing. PMID:12590423

  10. A first look at the dinoflagellate cysts abundance in the Bay of Bengal: implications on Late Quaternary productivity and climate change

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Patil, J.S.; Narale, D.D.; Anil, A.C.

    glacial period reflect the affinity to climate change between these two periods, like other regions. Greater abundance of heterotroph and autotroph cysts and higher species diversity were noticed during Holocene than in the last glacial period, which...

  11. Bacterial contribution to mitigation of iron and manganese in mangrove sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnan, K.P.; Fernandes, S.O.; Chandan, G.S.; LokaBharathi, P.A.

    with nitrifiers (NtB; representating autotroph) were chosen to assess the influence of the above-mentioned abiotic parameters on the former. The experimental site located along the Mandovi is under the influence of extensive ferromanganese ore mining, while...

  12. State Estimation for a Biological Phosphorus Removal Process using an Asymptotic Observer

    DEFF Research Database (Denmark)

    Larose, Claude Alain; Jørgensen, Sten Bay

    2001-01-01

    This study investigated the use of an asymptotic observer for state estimation in a continuous biological phosphorus removal process. The estimated states are the concentration of heterotrophic, autotrophic, and phosphorus accumulating organisms, polyphosphate, glycogen and PHA. The reaction scheme...

  13. The Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.; Naik, H.; Narvekar, P.V.

    , during the same cruises are consistent with the results of size fractionated PP (Tarran etal., 1999). [n general, pico-planktonic prokaryotcs. Synechococcus and Prochlorococcus dominated the autotrophic assemblages, and of the nano- and micro..., high abundances of nano- and micro autotrophs extended much farther offshore on TN050 when blooms of the prymnesiophyte Phaeocysti" were found at Stas. S7 and S 1I (Garrison et aI., 1998). During the late NEM (January-February) of 1995, sampled on TN...

  14. Liquid-nitrogen cryopreservation of three kinds of autotrophicbioleaching bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Xue-ling; XIN Xiao-hong; JIANG Ying; LIANG Ren-xing; YUAN Peng; FANG Cheng-xiang

    2008-01-01

    Three kinds of autotrophic bioleaching bacteria strains,including mesophilic and acidophilic ferrous ion-oxidizing bacteria Acidithiobacillus ferrooxidans (A.ferrooxidans),mesophilic and acidophilic sulfur-oxidizing bacteria Acidithiobacillus thiooxidans (A.thiooxidans),and moderately thermophilic sulfur-oxidizing bacteria Acidianus brierleyi,were cryopreserved in liquid nitrogen and their ferrous ion- or sulfur-oxidizing activities were investigated and compared with the original ones.The results revealed that ferrous ion/sulfur oxidation activities of the strains were almost equal before and after cryopreservation.Glycerin was used as cryoprotective agent.In conclusion,liquid-nitrogen cryopreservation is a simple and effective method for autotrophic bioleaching microorganisms.

  15. Enhancing biomass and ethanol production by increasing NADPH production in Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Choi, Yun-Nam; Park, Jong Moon

    2016-08-01

    This study demonstrates that increased NADPH production can improve biomass and ethanol production in cyanobacteria. We over-expressed the endogenous zwf gene, which encodes glucose-6-phosphate dehydrogenase of pentose phosphate pathway, in the model cyanobacterium Synechocystis sp. PCC 6803. zwf over-expression resulted in increased NADPH production, and promoted biomass production compared to the wild type in both autotrophic and mixotrophic conditions. Ethanol production pathway including NADPH-dependent alcohol dehydrogenase was also integrated with and without zwf over-expression. Excessive NADPH production by zwf over-expression could improve both biomass and ethanol production in the autotrophic conditions. PMID:26951740

  16. The Role of Diatom Nanostructures in Biasing Diffusion to Improve Uptake in a Patchy Nutrient Environment

    OpenAIRE

    Mitchell, James G; Seuront, Laurent; Doubell, Mark J.; Losic, Dusan; Voelcker, Nicolas H.; Seymour, Justin; Lal, Ratnesh

    2013-01-01

    Background Diatoms are important single-celled autotrophs that dominate most lit aquatic environments and are distinguished by surficial frustules with intricate designs of unknown function. Principal Findings We show that some frustule designs constrain diffusion to positively alter nutrient uptake. In nutrient gradients of 4 to 160 times over

  17. Distribution of micro-organisms along a transect in the South-East Pacific Ocean (BIOSOPE cruise) from epifluorescence microscopy

    Science.gov (United States)

    Masquelier, S.; Vaulot, D.

    2007-08-01

    The distribution of selected groups of micro-organisms was analyzed along a South-East Pacific Ocean transect sampled during the BIOSOPE cruise in 2004. The transect could be divided into four regions of contrasted trophic status: a high Nutrient Low Chlorophyll (HNLC) region (mesotrophic) near the equator, the South-East Pacific Ocean gyre (hyper-oligotrophic), the transition region between the gyre and the coast of South America (moderately oligotrophic), and the Chile upwelling (eutrophic). The abundance of phycoerythrin containing picocyanobacteria, autotrophic and heterotrophic eukaryotes in different size ranges, dinoflagellates, and ciliates was determined by epifluorescence microscopy after DAPI staining. All populations reached a maximum in the Chile upwelling and a minimum near the centre of the gyre. Picocyanobacteria reached a maximum abundance of 70×10³ cell mL-1. In the HNLC zone, up to 50% of picocyanobacteria formed colonies. Autotrophic eukaryote and dinoflagellate abundance reached 24.5×10³ and 200 cell mL-1, respectively. We observed a shift in the size distribution of autotrophic eukaryotes from 2-5 μm in eutrophic and mesotrophic regions to less than 2 μm in the central region. The contribution of autotrophic eukaryotes to total eukaryotes was the lowest in the central gyre. Maximum concentration of ciliates (18 cell ml-1) also occurred in the Chile upwelling, but, in contrast to the other groups, their abundance was very low in the HNLC zone and near the Marquesas Islands.

  18. Soil Respiration in Response to Landscape Position

    Science.gov (United States)

    Variations in soil type, due to landscape position, may influence soil respiration. This study was conducted to determine how landscape position (summit, side-slope, and depression) influences heterotrophic and autotrophic soil respiration. Soil respiration was determined at three landscape positio...

  19. Microbial lifestyles that enable survival in lithifying habitats

    DEFF Research Database (Denmark)

    Tamez-Hidalgo, Paulina

    2010-01-01

    The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone National Park occurs at a rapid rate, whereby microorganisms that colonize the ponds and apron facies are required to overcome lithification. CO2-fixation by autotrophic microorganisms in this cation-...

  20. Bacterial Microcompartments

    OpenAIRE

    Kerfeld, Cheryl A.

    2010-01-01

    Bacterialmicrocompartments (BMCs) are organelles composed entirely of protein. They promote specific metabolic processes by encapsulating and colocalizing enzymes with their substrates and cofactors, by protecting vulnerable enzymes in a defined microenvironment, and by sequestering toxic or volatile intermediates. Prototypes of the BMCsare the carboxysomes of autotrophic bacteria. However, structures of similar polyhedral shape are being discovered in an ever-increasing number of heterotroph...

  1. Chlorophyll fluorescence as a marker for herbicide mechanisms of action

    Science.gov (United States)

    Photosynthesis is the single most important source of O2 and organic chemical energy necessary to support all non-autotrophic life forms. Plants compartmentalize this elaborate biochemical process within chloroplasts in order to safely harness the power of solar energy and convert it into usable ch...

  2. Ecological evaluation of two prawn culture fields in the Cochin Backwater based on premonsoon diurnal observations

    Digital Repository Service at National Institute of Oceanography (India)

    Balasubramanian, T.; Viswakumar, M.; Venugopal, P.

    of prawns as these ponds are maintained in the autotrophic range with a P/R ratio greater than one under high production and respiration rates. Previous authors found a higher P/R ratio for the main backwater system, but without fulfilling the latter...

  3. Draft Genome Sequence of Acid-Tolerant Clostridium drakei SL1T, a Potential Chemical Producer through Syngas Fermentation

    OpenAIRE

    Jeong, Yujin; Song, Yoseb; Shin, Hyeon Seok; Cho, Byung-Kwan

    2014-01-01

    Clostridium drakei SL1T is a strictly anaerobic, H2-utilizing, and acid-tolerant acetogen isolated from an acidic sediment that is a potential platform for commodity chemical production from syngas fermentation. The draft genome sequence of this strain will enable determination of the acid resistance and autotrophic pathway of the acetogen.

  4. Genome Sequence of the Acetogenic Bacterium Moorella mulderi DSM 14980T

    Science.gov (United States)

    Castillo Villamizar, Genis Andrés

    2016-01-01

    Here, we report the draft genome sequence of Moorella mulderi DSM 14980T, a thermophilic acetogenic bacterium, which is able to grow autotrophically on H2 plus CO2 using the Wood-Ljungdahl pathway. The genome consists of a circular chromosome (2.99 Mb). PMID:27231372

  5. Carbon Dioxide in Arable Soil Profiles

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Plauborg, Finn; Heckrath, Goswin Johann;

    2014-01-01

    Carbon dioxide (CO2) concentrations in arable soil profiles are influenced by autotrophic and heterotrophic respiration as well as soil physical properties that regulate gas transport. Whereas different methods have been used to assess dynamics of soil CO2 concentrations, our understanding on the...

  6. Seasonal occurrence of anoxygenic photosynthesis in Tillari and Selaulim reservoirs, Western India

    Digital Repository Service at National Institute of Oceanography (India)

    Kurian, S.; Roy, R.; Repeta, D.J.; Gauns, M.; Shenoy, D.M.; Suresh, T.; Sarkar, A.; Narenkar, G.; Johnson, C.G.; Naqvi, S.W.A.

    conditions prevailed in the water column below the thermocline, the occurrence of photo-autotrophic bacteria was restricted only to mid-depths (maximal concentration of BChl e isomers was detected at 0.2% of the surface incident light). This shows...

  7. Next-generation sequencing reveals the impact of repetitive DNA in phylogenetically closely related genomes of Orobanchaceae

    OpenAIRE

    Piednoël, Mathieu; Aberer, Andre J.; Schneeweiss, Gerald M.; Macas, Jiri; Novak, Petr; Gundlach, Heidrun; Temsch, Eva M.; Renner, Susanne S

    2012-01-01

    We used next-generation sequencing to characterize the genomes of nine species of Orobanchaceae of known phylogenetic relationships, different life forms, and including a polyploid species. The study species are the autotrophic, nonparasitic Lindenbergia philippensis, the hemiparasitic Schwalbea americana, and seven nonphotosynthetic parasitic species of Orobanche (Orobanche crenata, Orobanche cumana, Orobanche gracilis (tetraploid), and Orobanche pancicii) and Phelipanche (Phelipanche lavand...

  8. Next-Generation Sequencing Reveals the Impact of Repetitive DNA Across Phylogenetically Closely Related Genomes of Orobanchaceae

    OpenAIRE

    Piednoël, Mathieu; Aberer, Andre J.; Schneeweiss, Gerald M.; Macas, Jiri; Novak, Petr; Gundlach, Heidrun; Temsch, Eva M.; Renner, Susanne S

    2012-01-01

    We used next-generation sequencing to characterize the genomes of nine species of Orobanchaceae of known phylogenetic relationships, different life forms, and including a polyploid species. The study species are the autotrophic, nonparasitic Lindenbergia philippensis, the hemiparasitic Schwalbea americana, and seven nonphotosynthetic parasitic species of Orobanche (Orobanche crenata, Orobanche cumana, Orobanche gracilis (tetraploid), and Orobanche pancicii) and Phelipanche (Phelipanche lavand...

  9. Biomass and nutrient productivities of Tetraselmis chuii under mixotrophic culture conditions with various C:N ratios

    Science.gov (United States)

    Lu, Lin; Wang, Jun; Yang, Guanpin; Zhu, Baohua; Pan, Kehou

    2016-05-01

    Mass microalgal culture plays an irreplaceable role in aquaculture, but microalgal productivity is restricted by traditional autotrophic culture conditions. In the present study, a Tetraselmis chuii strain belonging to the phylum Chlorophyta was isolated from south Yellow Sea. The growth rate and biomass productivity of this strain was higher under mixotrophic conditions with different carbon:nitrogen (C:N) ratios than those under autotrophic conditions. When the C:N ratio was 16, the optical density and biomass productivity were 3.7- and 5-fold higher than their corresponding values under autotrophic culture conditions, respectively. Moreover, T. chuii synthesized more polysaccharides and total lipids under mixotrophic conditions. In addition, T. chuii cultured under mixotrophic conditions synthesized more types of fatty acids than autotrophic culture conditions. At a C:N ratio of 16, the percentage of C16:0 and C18:1 reached 30.08% and 24.65% of the total fatty acid (TFA) content, respectively. These findings may provide a basis for largescale mixotrophic culture of T. chuii, as a potential bait-microalga.

  10. Ecology and trophic preference of picoplankton and nanoplankton in the Gulf of Mannar and the Palk Bay, southeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Mohan, A.P.; Jagadeesan, L.; Anjusha, A.; Muraleedharan, K.R.; KrishnaKiran, L.; Ullas, N.

    -74% in the PB) was prominently higher than the picoplankton (23-24% in GoM and 26-30% in the PB). The autotrophic nanoplankton alone contributed 59-63% and 31 – 36% of the total organic carbon available in pico and nano fractions in the GoM and PB respectively...

  11. Algumas controvérsias sobre a origem da vida Some controversies on the origin of life

    Directory of Open Access Journals (Sweden)

    Dimas A. M. Zaia

    2008-01-01

    Full Text Available In the present paper some controversies on the origin of life are discussed. Did the first living beings on Earth have an autotrophic or heterotrophic origin? What did come first, genetic code or metabolism? Were cells invented early? What was the role of minerals regarding the origin of life?

  12. Model-based evaluation of the role of Anammox on nitric oxide and nitrous oxide productions in membrane aerated biofilm reactor

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Smets, Barth F.; Yuan, Zhiguo;

    2013-01-01

    A multispecies one-dimensional biofilm model considering nitric oxide (NO) and nitrous oxide (N2O) productions for membrane aerated biofilm reactor (MABR) that remove nitrogen autotrophically through aerobic ammonia oxidation followed by Anammox is used to study the role of Anammox activity on th...

  13. Nitrification in acid coniferous forests: Some soils do, some soils don't

    NARCIS (Netherlands)

    Nugroho, R.A.

    2006-01-01

    Nitrification is a key process in the global nitrogen cycle. Ammonia-oxidising bacteria (AOB) were long thought to be the sole microorganisms capable of autotrophic ammonia oxidation, the rate-limited step in nitrification. This thesis elucidates the relation between the presence of AOB, environmen

  14. Kinetic models for nitrogen inhibition in ANAMMOX and nitrification process on deammonification system at room temperature

    Science.gov (United States)

    The performance of the deammonification process depends on the microbial activity of ammonia oxidizing bacteria (AOB) and ANAMMOX bacteria. These autotrophic organisms have different preferences for substrate, operating conditions and some external factors that may cause inhibition or imbalance of t...

  15. DECLINE IN SOIL CO2 EFFLUX FOLLOWING TREE GIRTLING IN MATURE BEECH AND SPRUCE STANDS IN GERMANY

    Science.gov (United States)

    Studies were undertaken to estimate the contribution of autotrophic respiration to total soil CO2 efflux in stands of mature European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Five mature trees of each species were girdled to eliminate carbo...

  16. ESTIMATING ROOT RESPIRATION IN SPRUCE AND BEECH: DECREASES IN SOIL RESPIRATION FOLLOWING GIRDLING

    Science.gov (United States)

    A study was undertaken to follow seasonal fluxes of CO2 from soil and to estimate the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) in a mixed stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Matu...

  17. Opposite metabolic responses of shoots and roots to drought

    Czech Academy of Sciences Publication Activity Database

    Gargallo-Garriga, A.; Sardans, J.; Pérez-Trujillo, M.; Rivas-Ubach, A.; Oravec, Michal; Večeřová, Kristýna; Urban, Otmar; Jentsch, A.; Kreyling, J.; Beierkuhnlein, C.; Parella, T.; Penuelas, J.

    2014-01-01

    Roč. 4, č. 6829 (2014), s. 1-7. ISSN 2045-2322 Grant ostatní: AV ČR(CZ) M200871201 Institutional support: RVO:67179843 Keywords : shoot and roots * autotrophic and heterotrophic organs * environmental change * growth metabolism * water and nutirens Subject RIV: EH - Ecology, Behaviour Impact factor: 5.578, year: 2014

  18. Comparative-Analysis of Gene-Sequences Encoding Ammonia Monooxygenase of Nitrosospira Sp Ahb1 and Nitrosolobus- Multiformis C-71

    NARCIS (Netherlands)

    Rotthauwe, J.H.; De Boer, W.; Liesack, W.

    1995-01-01

    DNA encoding ammonia monooxygenase from two phylogenetically related autotrophic nitrifying bacteria, Nitrosospira sp. AHB1 and Nitrosolobus multiformis C-71, was amplified by PCR, The resulting products were cloned into the vector pCR-Script, A continuous region of DNA of about 1.5 kb for strain AH

  19. Viral lysis of Phaeocystis pouchetii: implications for algal population dynamics and heterotrophic C, N and P cycling

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Middelboe, Mathias

    2009-01-01

    A model ecosystem with two autotrophic flagellates, Phaeocystis pouchetii and Rhodomonas salina, a virus specific to P. pouchetii (PpV) and bacteria and heterotrophic nanoflagellates was used to investigate effects of viral lysis on algal population dynamics and heterotrophic nitrogen and...

  20. Ciliates and their picophytoplankton-feeding activity in a high altitude warm-monomictic saline lake

    Czech Academy of Sciences Publication Activity Database

    Peštová, D.; Macek, Miroslav; Pérez, M. E. M.

    2008-01-01

    Roč. 44, č. 1 (2008), s. 13-25. ISSN 0932-4739 Institutional research plan: CEZ:AV0Z60170517 Keywords : ciliates * autotrophic picoplankton * feeding rates Subject RIV: EH - Ecology, Behaviour Impact factor: 1.000, year: 2008

  1. Misconceptions on the Biological Concept of Food: Results of a Survey of High School Students.

    Science.gov (United States)

    Lee, Y. J.; Diong, C. H.

    This paper explains the results of a survey of students' ideas about food as a scientific concept. The survey found that high school students in Singapore (n=66) displayed an anthropocentric view of food that was not generally applied across living organisms in heterotrophs (animals) or autotrophs (plants) as a whole. It is also noted that…

  2. Ecosystem metabolism in a temporary Mediterranean marsh (Donana National Park, SW Spain)

    DEFF Research Database (Denmark)

    Geertz-Hansen, O.; Montes, C.; Duarte, C.M.; Jensen, Kaj Sand; Marba, N.; Grillas, P.

    2011-01-01

    metabolic balance of the open waters supporting submerged macrophytes of the Donana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community (benthic + pelagic) was net autotrophic with net community production rates averaging 0.61 g C m(-2) d(-1), and...

  3. Development of the trophic part of consortia’s relations of the gossamer-winged butterflies (Lepidoptera, Lycaenidae with Salvia nutans (Lamiaceae

    Directory of Open Access Journals (Sweden)

    K. K. Goloborodko

    2008-03-01

    Full Text Available On the basis of dummy individual consortia of Salvia nutans L. an important component of fertilization mechanism – the dynamics of trophic relations of antophylus agents with an entomophilous angiosperm autotroph was investigated. The dominant position in species structure of fertilizers in conditionally native steppe ecosystems is occupied by relict TomaresnogelidobrogensisCar.

  4. Influence of detachment mechanisms on competition in biofilms

    DEFF Research Database (Denmark)

    Morgenroth, Eberhard Friedrich; Wilderer, P. A.

    2000-01-01

    autotrophic biomass in situations with long intervals between detachment with resulting high variations of the bio®lm thickness. It is concluded that the application of results from mathematical models assuming a constant bio®lm thickness may be misleading when predicting the performance of systems with large...

  5. GROWTH RATES, PHYSIOLOGICAL INDICATORS AND ELEMENTAL COMPOSITION OF THE RED-TIDE DINOFLAGELLATE, ALEXANDRIUM MONILATUM

    Science.gov (United States)

    Alexandrium monilatum is a thecate, autotrophic, bioluminescent and chain-forming dinoflagellate. Although it has been known to be associated with red tides and fish kills along the US Gulf of Mexico coast for almost 50 years, little basic physiological information is available f...

  6. THE RED-TIDE DINOFLAGELLATE, ALEXANDRIUM MONILATUM, SUPPRESSES GROWTH OF MIXED NATURAL PHYTOPLANKTON

    Science.gov (United States)

    Alexandrium monilatum is a large, chain-forming, autotrophic dinoflagellate associated with red-tides and fish kills along the US Gulf of Mexico coast. When cultured inocula of A. monilatum were added to nutrient-amended seawater samples, growth rates and biomass yields of the na...

  7. What's the flux? Unraveling how CO2 fluxes from trees reflect underlying physiological processes

    Energy Technology Data Exchange (ETDEWEB)

    Trumbore, Susan E. [Max-Planck Institute for Biogeochemistry, Jena (Germany); Angert, Alon [Hebrew Univ. of Jerusalem (Israel). The Institute of Earth Sciences; Kunert, Norbert [Max-Planck Institute for Biogeochemistry, Jena (Germany); Muhr, Jan [Max-Planck Institute for Biogeochemistry, Jena (Germany); Chambers, Jeffrey Q. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Climate Sciences Dept.

    2012-12-18

    We report that the CO2 emitted from a stem is produced by physiological processes, but the challenge remains identifying what portion is produced by local tissues, which will facilitate much-needed mechanistic understanding of factors controlling autotrophic respiration.

  8. Algumas controvérsias sobre a origem da vida Some controversies on the origin of life

    OpenAIRE

    Dimas A. M. Zaia; Cássia Thaïs B. V. Zaia

    2008-01-01

    In the present paper some controversies on the origin of life are discussed. Did the first living beings on Earth have an autotrophic or heterotrophic origin? What did come first, genetic code or metabolism? Were cells invented early? What was the role of minerals regarding the origin of life?

  9. Habitat connectivity and ecosystem productivity: implications from a simple model.

    Science.gov (United States)

    Cloern, J.E.

    2007-01-01

    The import of resources (food, nutrients) sustains biological production and food webs in resource-limited habitats. Resource export from donor habitats subsidizes production in recipient habitats, but the ecosystem-scale consequences of resource translocation are generally unknown. Here, I use a nutrient-phytoplankton-zooplankton model to show how dispersive connectivity between a shallow autotrophic habitat and a deep heterotrophic pelagic habitat can amplify overall system production in metazoan food webs. This result derives from the finite capacity of suspension feeders to capture and assimilate food particles: excess primary production in closed autotrophic habitats cannot be assimilated by consumers; however, if excess phytoplankton production is exported to food-limited heterotrophic habitats, it can be assimilated by zooplankton to support additional secondary production. Transport of regenerated nutrients from heterotrophic to autotrophic habitats sustains higher system primary production. These simulation results imply that the ecosystem-scale efficiency of nutrient transformation into metazoan biomass can be constrained by the rate of resource exchange across habitats and that it is optimized when the transport rate matches the growth rate of primary producers. Slower transport (i.e., reduced connectivity) leads to nutrient limitation of primary production in autotrophic habitats and food limitation of secondary production in heterotrophic habitats. Habitat fragmentation can therefore impose energetic constraints on the carrying capacity of aquatic ecosystems. The outcomes of ecosystem restoration through habitat creation will be determined by both functions provided by newly created aquatic habitats and the rates of hydraulic connectivity between them.

  10. DIVERSITY OF PLANKTON IN BIRNAL RESERVIOR WITH SPECIAL REFERENCE TO PHYTOPLANKTON

    OpenAIRE

    Deshmukh. S. B; Gonjare. G. R

    2014-01-01

    Phytoplankton's are microscopic autotrophs forming communities and Remain suspended in water up to the effective light penetration. Planktons are found in fresh; Marine and brackish water.Planktons are divided in phytoplankton and zooplankton. Phytoplankton constitute the basic food sourceof any aquatic ecosystem; which supports Aquatic animals such as fish's .The zooplanktons are the major mode of energy between Phytoplankton and fish.

  11. The role of photosynthesis and food uptake for the growth of marine mixotrophic dinoflagellates

    DEFF Research Database (Denmark)

    Hansen, Per Juel

    2011-01-01

    Mixotrophy (i.e. combined use of photosynthesis and food uptake for growth) is widespread among marine dinoflagellates. Species with permanent chloroplasts generally display a growth response towards irradiance like an ordinary autotrophic alga. However, some species cannot grow in the light on a...

  12. Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.

    Science.gov (United States)

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent…

  13. [Simultaneous Biotransformation of Ammonium and Nitrate via Zero-Valent Iron on Anaerobic Conditions].

    Science.gov (United States)

    Zhou, Jian; Huang, Yong; Yuan, Yi; Liu, Xin; Li, Xiang; Shen, Jie; Yang, Peng-bing

    2015-12-01

    Zero-valent iron (ZVI) was used to improve the biological autotrophic denitrification process between nitrate and ammonia by anaerobic ammonia oxidation ( ANAMMOX) bacteria. With the addition of ZVI, the biological autotrophic denitrification process could be reacted in the influent condition of pH was 7-8, at 35°C ±0.5°C, the concentration of ammonia was 50-100 mg · L⁻¹ and the concentration of nitrate was 50-100 mg · L⁻¹. The highest conversion rate could be reached to 17.2 mg · (L·h) ⁻¹. With the change of reaction time and the molar ratio of nitrate and ammonia in influent, the final molar conversion ratio of nitrate and ammonia in effluent fluctuated between 1.2-3. 5. The result showed that this autotrophic denitrification process was not belonged to elementary reaction. The mechanism of this autotrophic denitrification process could be summarized that with the reduction of ZVI, the nitrate could be reduced to nitrite. Hereafter, the ANAMMOX process reacted between the nitrite and ammonia. PMID:27011992

  14. Controlling effects of irradiance and heterotrophy on carbon translocation in the temperate coral Cladocora caespitosa.

    Directory of Open Access Journals (Sweden)

    Pascale Tremblay

    Full Text Available Temperate symbiotic corals, such as the Mediterranean species Cladocora caespitosa, live in seasonally changing environments, where irradiance can be ten times higher in summer than winter. These corals shift from autotrophy in summer to heterotrophy in winter in response to light limitation of the symbiont's photosynthesis. In this study, we determined the autotrophic carbon budget under different conditions of irradiance (20 and 120 µmol photons m(-2 s(-1 and feeding (fed three times a week with Artemia salina nauplii, and unfed. Corals were incubated in H(13CO(3 (--enriched seawater, and the fate of (13C was followed in the symbionts and the host tissue. The total amount of carbon fixed by photosynthesis and translocated was significantly higher at high than low irradiance (ca. 13 versus 2.5-4.5 µg cm(-2 h(-1, because the rates of photosynthesis and carbon fixation were also higher. However, the percent of carbon translocation was similar under the two irradiances, and reached more than 70% of the total fixed carbon. Host feeding induced a decrease in the percentage of carbon translocated under low irradiance (from 70 to 53%, and also a decrease in the rates of carbon translocation per symbiont cell under both irradiances. The fate of autotrophic and heterotrophic carbon differed according to irradiance. At low irradiance, autotrophic carbon was mostly respired by the host and the symbionts, and heterotrophic feeding led to an increase in host biomass. Under high irradiance, autotrophic carbon was both respired and released as particulate and dissolved organic carbon, and heterotrophic feeding led to an increase in host biomass and symbiont concentration. Overall, the maintenance of high symbiont concentration and high percentage of carbon translocation under low irradiance allow this coral species to optimize its autotrophic carbon acquisition, when irradiance conditions are not favourable to photosynthesis.

  15. Multiple stressors for oceanic primary production

    KAUST Repository

    Agusti, Susana

    2015-12-15

    Marine ecosystems are increasingly exposed to stress factors of anthropogenic origin that change their function, structure and services they deliver society. Climate change occurs simultaneously with other changes in the environment acting jointly in a context of global environmental change. For oceanic phytoplankton communities, the research conducted so far has identified stress factors associated with global change and their impact individually (warming, acidification, increased UVB radiation, pollutants). But when several stressors act simultaneously interactions and responses are not equal to the sum of individual impacts, but may have synergistic effects (the effects are multiplied) or antagonistic (cancel out the effects) that hinder predictions of the vulnerability of ecosystems to global change. Here we will examine the vulnerability of oceanic primary producers to the accumulation of different stressors associated with global change. The trend for autotrophic picoplankton to increase with temperature in the ocean has led to predictions that autotrophic picoplankton abundance will increase with warming. However, it is documented a trend towards a decline in productivity, due to declined autotroph biomass and production with warming and the associated stratification in the subtropical ocean. Models predicting an increase in abundance are in contradiction with the reported decrease in productivity in several oceanic areas, and associate oligotrophication. Here we perform a global study to analyze the relationships of autotrophic picoplankton with oceanic temperature, nutrients, underwater light and ultraviolet B (UVB) radiation, and productivity. We built a model to project the future changes of autotrophic picoplankton considering multiple environmental changes in future climate scenarios for the subtropical gyres. We considered increased water temperature, and associated changes in productivity and underwater light and UVB. The model show that warming and

  16. Assessing the ecological status of plankton in Anjos Bay: a flow cytometry approach

    Science.gov (United States)

    Pereira, G. C.; de Figuiredo, A. R.; Jabor, P. M.; Ebecken, N. F. F.

    2010-08-01

    This aim of this paper is to assess the use of the heterotrophic/autotrophic ratio as an early indicator of trophic status as a part of development of a real time monitoring program at Anjos Bay, Rio de Janeiro, Brazil. An in-situ flow cytometer was used to quantify the abundances of phytoplankton and cyanobacteria, which were identified by chlorophyll and phycoerythrin autofluorescence, respectively. Heterotrophic prokaryotes and viruses were quantified by DNA-binding fluorochromes; merozooplankton larvae were collected by plankton net and quantified by stereomicroscopy. The temporal and spatial distributions of these variables were evaluated on the basis of weekly observations from August 2006 to September 2007. The heterotrophic/autotrophic ratio and the viral abundance were correlated with upwelling events and assume an apparently seasonal pattern. A possible control mechanism and influential factors are discussed, and it is concluded that this ecosystem is bottom-up controlled under eutrophic conditions and top-down controlled under oligotrophic conditions.

  17. Heterotrophs are key contributors to nitrous oxide production in mixed liquor under low C-to-N ratios during nitrification - batch experiments and modelling

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Pellicer i Nàcher, Carles; Petersen, Morten S.;

    2016-01-01

    model structures have been proposed without consensus calibration procedures. Here, we present a new experimental design that was used to calibrate AOB-driven N2O dynamics of a mixed culture. Even though AOB activity was favoured with respect to HB, oxygen uptake rates indicated HB activity. Hence......Nitrous oxide (N2O), a by-product of biological nitrogen removal during wastewater treatment, is produced by ammonia-oxidizing bacteria (AOB) and heterotrophic denitrifying bacteria (HB). Mathematical models are used to predict N2O emissions, often including AOB as the main N2O producer. Several......, rigorous experimental design for calibration of autotrophic N2O production from mixed cultures is essential. The proposed N2O production pathways were examined using five alternative process models confronted with experimental data inferred. Individually, the autotrophic and heterotrophic denitrification...

  18. Evaluation of the Influence of Extracellular Polymeric Substances on the Mass Transport of Substrate within Multispecies Biofilms

    Institute of Scientific and Technical Information of China (English)

    曹宏斌; 李鑫钢; 姜斌; 孙津生; 张懿

    2004-01-01

    A model, for evaluating the effect of porosity and volume fraction of extracellular polymeric substances (EPS) within multispecies biofilms on the effective diffusivity, is developed and experimentally validated, based on the extraction of EPS from intact biofilms. The amount of EPS in biofilms significantly affects the effective diffusivity. For biofilms with porosity of 77%—95% in the top layers and 54%—58% in the bottom layers, the value of De/Dw decreases from 0.52—0.83 in the top layers to 0.23—0.31 in the bottom layers. Generally, the effective diffusivity in the heterotrophic/autotrophic biofilms is slightly lower than that in the heterotrophic biofilms, due to the lower porosity in the heterotrophic/autotrophic biofilms.

  19. 胞外高分子物质对基质在复合生物膜内传质速率影响的测定%Evaluation of the Influence of Extracellular Polymeric Substances on the Mass Transport of Substrate within Multispecies Biofilms

    Institute of Scientific and Technical Information of China (English)

    曹宏斌; 李鑫钢; 姜斌; 孙津生; 张懿

    2004-01-01

    A model, for evaluating the effect of porosity and volume fraction of extracellular polymeric substances(EPS) within multispecies biofilms on the effective diffusivity, is developed and experimentally validated, based on the extraction of EPS from intact biofilms. The amount of EPS in biofilms significantly affects the effective diffusivity. For biofilms with porosity of 77%-95% in the top layers and 54%-58% in the bottom layers, the value of De/Dw decreases from 0.52-0.83 in the top layers to 0.23-0.31 in the bottom layers. Generally, the effective diffusivity in the heterotrophic/autotrophic biofilms is slightly lower than that in the heterotrophic biofilms, due to the lower porosity in the heterotrophic/autotrophic biofilms.

  20. Identifizierung der Nitratabbauprozesse und Prognose des Nitratabbaupotenzials in den Sedimenten des Hessischen Rieds

    Science.gov (United States)

    Kludt, Christoph; Weber, Frank-Andreas; Bergmann, Axel; Knöller, Kay; Berthold, Georg; Schüth, Christoph

    2016-03-01

    Microbial denitrification contributes significantly to the mitigation of nitrate contamination in sedimentary aquifers by reducing nitrate coupled to the consumption of organic carbon (heterotrophic) and iron sulphides like pyrite (autotrophic). However, these phases are often only present in trace amounts and can become depleted, so that denitrification will eventually cease. In order to implement measures within the EC-Water Framework Directive, we investigated the denitrification potential and the denitrification processes in the sediments of the Hessian Ried. The reduction potential was quantified and characterized by solid-phase analyses of drill core samples. Depth-oriented investigations of hydrochemistry (i.e. stable isotopes, N2Excess) allowed determining nitrate input, reduction progress and average reduction kinetics upstream of selected wells. Despite low sulphide contents (max. 123 mg-S/kg), autotrophic denitrification was typically the dominant process. The results can be used to delineate risk areas, downstream of which denitrification can be expected to cease in the near future.

  1. The membrane biofilm reactor: the natural partnership of membranes and biofilm.

    Science.gov (United States)

    Rittmann, B E

    2006-01-01

    Many exciting new technologies for water-quality control combine microbiological processes with adsorption, advanced oxidation, a membrane or an electrode to improve performance, address emerging contaminants or capture renewable energy. An excellent example is the H2-based membrane biofilm reactor (MBfR), which delivers H2 gas to a biofilm that naturally accumulates on the outer surface of a bubbleless membrane. Autotrophic bacteria in the biofilm oxidise the H2 and use the electrons to reduce NO3-, CIO4- and other oxidised contaminants. This natural partnership of membranes and biofilm makes it possible to gain many cost, performance and simplicity advantages from using H2 as the electron donor for microbially catalysed reductions. The MBfR has been demonstrated for denitrification in drinking water; reduction of perchlorate in groundwater; reduction of selenate, chromate, trichloroethene and other emerging contaminants; advanced N removal in wastewater treatment and autotrophic total-N removal. PMID:16605035

  2. Effects of hydrography on the distribution of bacteria and virus in Cochin Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Jasna, V.; Jina, S.; Jayalakshmy, K.V.; Lallu, K.R.; Madhu, N.V.; Muraleedharan, K.R.; NaveenKumar, K.R.; Balachandran, K.K.

    indicating the complex nature of the system (Ramamirtham and Muthusamy, 1986; Balachandran et al., 2008). Importantly, the CE has undergone drastic transformations over the past five decades and the increased microbial activity has transformed it from... an autotrophic to a highly heterotrophic system (Thottathil et al., 2008a; Gupta et al., 2009). The viruses play a crucial role in lysing bacterial and phytoplankton cells to release the dissolved organic matter and thereby increasing the community respiration...

  3. Diurnal variations in bacterial and viral production in Cochin estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Jasna, V.; Haridevi, C.K.; Jina, S.; Greeshma, M.; Breezy, J.; Nair, M.

    . 200; Weinbauer and Rassoulzadegan 2004), up to 70% cyanobacterial mortality (Proctor and Fuhrman 1990) and 10-70 % phytoplankton mortality in the aquatic systems (Jacquet et al. 2002; Nagasaki 2008). This in turn affects the biogeochemical cycling... of nutrients and dissolved organic matter (DOM) pool in the ecosystem (Bratbak et al. 1992; Sime- Ngando et al. 2008; Winget and Wommack 2009). Light is the most important physical factor that influences both autotrophic processes and the short...

  4. Influence of Extractive Solvents on Lipid and Fatty Acids Content of Edible Freshwater Algal and Seaweed Products, the Green Microalga Chlorella kessleri and the Cyanobacterium Spirulina platensis

    OpenAIRE

    Jarmila Vavra Ambrozova; Ladislava Misurcova; Robert Vicha; Ludmila Machu; Dusan Samek; Mojmir Baron; Jiri Mlcek; Jiri Sochor; Tunde Jurikova

    2014-01-01

    Total lipid contents of green (Chlorella pyrenoidosa, C), red (Porphyra tenera, N; Palmaria palmata, D), and brown (Laminaria japonica, K; Eisenia bicyclis, A; Undaria pinnatifida, W, WI; Hizikia fusiformis, H) commercial edible algal and cyanobacterial (Spirulina platensis, S) products, and autotrophically cultivated samples of the green microalga Chlorella kessleri (CK) and the cyanobacterium Spirulina platensis (SP) were determined using a solvent mixture of methanol/chloroform/water (1:2:...

  5. Distribution of micro-organisms along a transect in the South-East Pacific Ocean (BIOSOPE cruise using epifluorescence microscopy

    Directory of Open Access Journals (Sweden)

    S. Masquelier

    2008-03-01

    Full Text Available The distribution of selected groups of micro-organisms was analyzed along a South-East Pacific Ocean transect sampled during the BIOSOPE cruise in 2004. The transect could be divided into four regions of contrasted trophic status: a High Nutrient Low Chlorophyll (HNLC region (mesotrophic near the equator, the South-East Pacific Ocean gyre (hyper-oligotrophic, a transition region between the gyre and the coast of South America (moderately oligotrophic, and the Chile upwelling (eutrophic. The abundance of phycoerythrin containing picocyanobacteria (PE picocyanobacteria, autotrophic and heterotrophic eukaryotes (classified into different size ranges, dinoflagellates, and ciliates was determined by epifluorescence microscopy after DAPI staining. Despite some apparent loss of cells due to sample storage, distribution patterns were broadly similar to those obtained by flow cytometry for PE picocyanobacteria and picoeukaryotes. All populations reached a maximum in the Chile upwelling and a minimum near the centre of the gyre. The maximum abundance of PE picocyanobacteria was 70 103 cell mL−1. Abundance of autotrophic eukaryotes and dinoflagellates reached 24.5 103 and 20 cell mL−1, respectively. We observed a shift in the size distribution of autotrophic eukaryotes from 2–5 μm in eutrophic and mesotrophic regions to less than 2 μm in the central region. The contribution of autotrophic eukaryotes to total eukaryotes was the lowest in the central gyre. Maximum concentration of ciliates (18 cell mL−1 also occurred in the Chile upwelling, but, in contrast to the other groups, their abundance was very low in the HNLC zone and near the Marquesas Islands. Two key findings of this work that could not have been observed with other techniques are the high percentage of PE picocyanobacteria forming colonies in the HLNC region and the observation of numerous dinoflagellates with bright green

  6. Distribution of micro-organisms along a transect in the South-East Pacific Ocean (BIOSOPE cruise from epifluorescence microscopy

    Directory of Open Access Journals (Sweden)

    S. Masquelier

    2007-08-01

    Full Text Available The distribution of selected groups of micro-organisms was analyzed along a South-East Pacific Ocean transect sampled during the BIOSOPE cruise in 2004. The transect could be divided into four regions of contrasted trophic status: a high Nutrient Low Chlorophyll (HNLC region (mesotrophic near the equator, the South-East Pacific Ocean gyre (hyper-oligotrophic, the transition region between the gyre and the coast of South America (moderately oligotrophic, and the Chile upwelling (eutrophic. The abundance of phycoerythrin containing picocyanobacteria, autotrophic and heterotrophic eukaryotes in different size ranges, dinoflagellates, and ciliates was determined by epifluorescence microscopy after DAPI staining. All populations reached a maximum in the Chile upwelling and a minimum near the centre of the gyre. Picocyanobacteria reached a maximum abundance of 70×10³ cell mL−1. In the HNLC zone, up to 50% of picocyanobacteria formed colonies. Autotrophic eukaryote and dinoflagellate abundance reached 24.5×10³ and 200 cell mL−1, respectively. We observed a shift in the size distribution of autotrophic eukaryotes from 2–5 μm in eutrophic and mesotrophic regions to less than 2 μm in the central region. The contribution of autotrophic eukaryotes to total eukaryotes was the lowest in the central gyre. Maximum concentration of ciliates (18 cell ml−1 also occurred in the Chile upwelling, but, in contrast to the other groups, their abundance was very low in the HNLC zone and near the Marquesas Islands.

  7. Distribution of micro-organisms along a transect in the South-East Pacific Ocean (BIOSOPE cruise) using epifluorescence microscopy

    Science.gov (United States)

    Masquelier, S.; Vaulot, D.

    2008-03-01

    The distribution of selected groups of micro-organisms was analyzed along a South-East Pacific Ocean transect sampled during the BIOSOPE cruise in 2004. The transect could be divided into four regions of contrasted trophic status: a High Nutrient Low Chlorophyll (HNLC) region (mesotrophic) near the equator, the South-East Pacific Ocean gyre (hyper-oligotrophic), a transition region between the gyre and the coast of South America (moderately oligotrophic), and the Chile upwelling (eutrophic). The abundance of phycoerythrin containing picocyanobacteria (PE picocyanobacteria), autotrophic and heterotrophic eukaryotes (classified into different size ranges), dinoflagellates, and ciliates was determined by epifluorescence microscopy after DAPI staining. Despite some apparent loss of cells due to sample storage, distribution patterns were broadly similar to those obtained by flow cytometry for PE picocyanobacteria and picoeukaryotes. All populations reached a maximum in the Chile upwelling and a minimum near the centre of the gyre. The maximum abundance of PE picocyanobacteria was 70 103 cell mL-1. Abundance of autotrophic eukaryotes and dinoflagellates reached 24.5 103 and 20 cell mL-1, respectively. We observed a shift in the size distribution of autotrophic eukaryotes from 2-5 μm in eutrophic and mesotrophic regions to less than 2 μm in the central region. The contribution of autotrophic eukaryotes to total eukaryotes was the lowest in the central gyre. Maximum concentration of ciliates (18 cell mL-1) also occurred in the Chile upwelling, but, in contrast to the other groups, their abundance was very low in the HNLC zone and near the Marquesas Islands. Two key findings of this work that could not have been observed with other techniques are the high percentage of PE picocyanobacteria forming colonies in the HLNC region and the observation of numerous dinoflagellates with bright green autofluorescence.

  8. Genetic Engineering: A Promising Tool to Engender Physiological, Biochemical, and Molecular Stress Resilience in Green Microalgae

    OpenAIRE

    Guihéneuf, Freddy; Khan, Asif; Tran, Lam-Son P.

    2016-01-01

    As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest toward a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy ...

  9. Genetic engineering: a promising tool to engender physiological, biochemical and molecular stress resilience in green microalgae

    OpenAIRE

    Freddy eGuiheneuf; Asif eKhan; Lam-Son ePhan Tran

    2016-01-01

    As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest towards a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy...

  10. Thallophytic algal flora from a new Silurian Lagerstätte

    OpenAIRE

    Tinn, Oive; Meidla, Tõnu; Ainsaar, Leho; Pani, Tõnu

    2009-01-01

    Algae have always been the most diverse and numerous eukaryotic autotrophs in marine ecosystems. Both fossil andmolecular data point to an early Proterozoic origin for algae. Although known for their long evolutionary history, the fossil recordof algae is sparse and mainly remains of taxa with heavily calcified thalli are preserved. However, fossils of noncalcareous algae,known as extremely sporadic and occasional finds from different parts of the world, provide important insights into thepal...

  11. Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers

    Institute of Scientific and Technical Information of China (English)

    许恒龙; MIN; Gi-Sik; CHOI; Joong-Ki; 朱明壮; 姜勇; AL-RASHEID; Khaled; A.S.

    2010-01-01

    The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to ...

  12. Linking Heterotrophic Metabolism and Nutrient Uptake in Headwater Streams

    OpenAIRE

    Gray, Travis Michael

    2007-01-01

    Autotrophs and heterotrophs differ in their demand, acquisition and use of materials, but fundamentally nutrient demand is inherently linked to metabolism based on the stoichiometry of biochemical reactions. The differences between these two groups of organisms confound straightforward regression approaches to quantifying the relationship between nutrient demand and metabolism at an ecosystem level. We address how nutrient demand in headwater streams changes with shifts in organic matter su...

  13. Highly Active Microbial Communities in the Ice and Snow Cover of High Mountain Lakes

    OpenAIRE

    Felip, M.; Sattler, B.; Psenner, R.; Catalan, J

    1995-01-01

    An exploratory study carried out in Pyrenean and Alpine lakes shows that a rich, active microbial community lives in the slush layers of the winter cover of such lakes in spite of the low temperature and the seasonal occurrence of the habitat. Bacteria were very diverse in morphology, with filaments reaching up to 100 (mu)m long; flagellates, both autotrophic (chrysophytes, cryptophytes, dinoflagellates, and volvocales) and heterotrophic, and ciliates were abundant, reaching biovolume values ...

  14. Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

    OpenAIRE

    Ehrenfeld Nicole; Ugalde Juan A; Levicán Gloria; Maass Alejandro; Parada Pilar

    2008-01-01

    Abstract Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacter...

  15. Picoplankton Community Composition by CARD-FISH and Flow Cytometric Techniques: A Preliminary Study in Central Adriatic Sea Water

    OpenAIRE

    Anita Manti; Paola Boi; Federica Semprucci; Rosaria Cataudella; Stefano Papa

    2012-01-01

    Data concerning picoplanktonic community composition and abundance in the Central Adriatic Sea are presented in an effort to improve the knowledge of bacterioplankton and autotrophic picoplankton and their seasonal changes. Flow cytometry analyses revealed the presence of two distinct bacteria populations: HNA and LNA cells. HNA cells showed an explicit correlation with viable and actively respiring cells. The study of viability and activity may increase our knowledge of the part that con...

  16. How does abundance scale with body size in coupled size-structured food webs?

    OpenAIRE

    Julia L Blanchard; Jennings, Simon; Law, Richard; Castle, Matthew D.; Mccloghrie, Paul; Rochet, Marie-joelle; Benoit, Eric

    2009-01-01

    Widely observed macro-ecological patterns in log abundance vs. log body mass of organisms can be explained by simple scaling theory based on food (energy) availability across a spectrum of body sizes. The theory predicts that when food availability falls with body size (as in most aquatic food webs where larger predators eat smaller prey), the scaling between log N vs. log m is steeper than when organisms of different sizes compete for a shared unstructured resource (e.g. autotrophs, herbivor...

  17. Tracking heavy water (D2O) incorporation for identifying and sorting active microbial cells

    DEFF Research Database (Denmark)

    Berry, David; Mader, Esther; Lee, Tae Kwon;

    2015-01-01

    active microbes on the single-cell level in complex samples using stable isotope probing with heavy water (D2O) combined with Raman microspectroscopy. Incorporation of D2O-derived D into the biomass of autotrophic and heterotrophic bacteria and archaea could be unambiguously detected via C-D signature...... potential of the nondestructive D2O-Raman approach for targeted sorting of microbial cells with defined functional properties for singlecell genomics....

  18. Widespread methanotrophic primary production in lowland chalk rivers

    OpenAIRE

    Shelley, Felicity; Grey, Jonathan; Trimmer, Mark

    2014-01-01

    Methane is oversaturated relative to the atmosphere in many rivers, yet its cycling and fate is poorly understood. While photosynthesis is the dominant source of autotrophic carbon to rivers, chemosynthesis and particularly methane oxidation could provide alternative sources of primary production where the riverbed is heavily shaded or at depth beneath the sediment surface. Here, we highlight geographically widespread methanotrophic carbon fixation within the gravel riverbeds of over 30 chalk...

  19. Biological removal of phosphorus and nitrogen from wastewater : new insights from metagenomic and metatranscriptomic approaches

    OpenAIRE

    Mao, Yanping; 毛艷萍

    2014-01-01

    The study was conducted to reveal the insights of microbial diversity, functional profile and gene expression of microorganisms responsible for enhanced biological phosphorus removal (EBPR) and hydrogen-oxidizing autotrophic denitrification mainly by using metagenomic and metatranscriptomic analysis based on high-throughput sequencing. Two sequencing batch reactors (SBRs) were operated to remove phosphorus (15 mg/L) from synthetic wastewater. The integrated metagenomic and metatranscripto...

  20. Molecular and phenotypic characterization of endophytic Sebacinoid strains

    OpenAIRE

    Basiewicz, Magdalena

    2010-01-01

    The order Sebacinales belongs to a taxonomically, ecologically, and physiologically diverse group of fungi within the Phylum Basidiomycota. Using several molecular techniques they were detected all over the world. Few isolates, classified into the clade B, are available at the moment: the root–colonizing mutualistic fungus Piriformospora indica, various Sebacina vermifera isolates from autotrophic orchids, as well as Piriformospora glomeralium (ex multinucleate rhizoctonia DAR29830, Warcup). ...

  1. Characterization of purple and green photosynthetic bacteria isolated from the lagoon of Agatti Atoll (Lakshadweep Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Chandramohan, D.

    physiologically but with common anoxygenic photosynthesis using only one photosystem. They are different from cyanobacteria in that the latter group will carry out oxygenic photo- synthesis using two photosystems1. The contribution of photosynthetic bacteria... characters , cell size and ability for photo hyphenminus autotroph y permit the m to be tentatively identified as Chromatium violascens. The possibilit y o f identifying th e presen t strai n a s either Chr. warmingii o r Chr. buderi whic h ar e als o...

  2. Metabolism and Gaseous Exchanges in Two Coastal Lagoons from Rio de Janeiro with Distinct Limnological Characteristics

    OpenAIRE

    Thomaz Sidinei M.; Enrich-Prast Alex; Gonçalves Jr. José F.; Santos Anderson M. dos; Esteves Francisco A.

    2001-01-01

    The global metabolism and exchange of gases with the atmosphere were measured during a diel cycle in two tropical coastal lagoons, using the curves of carbon dioxide and dissolved oxygen. Heterotrophic metabolism (net CO2 production and net O2 consumption) was observed in a black water lagoon (Comprida), and autotrophic metabolism (net O2 production and net CO2 consumption) in a clear water lagoon (Imboassica). These differences were attributed to the limnological characteristics of both ecos...

  3. The effects of prolonged darkness on temperate and tropical marine phytoplankton, and their implications for ballast water risk management

    Digital Repository Service at National Institute of Oceanography (India)

    Carney, K.J.; Delany, J.E.; Sawant, S.S.; Mesbahi, E.

    environment by these introduced organisms. Ballast tanks are hostile environments with no light to support growth of autotrophs over long periods, which consequently affects grazing populations. Food and nutrient availability, temperature, and chemical..., as has been demonstrated in a number of studies on polar and temperate species (Anita 1976; Peters 1996; Peters and Thomas, 1996). These studies did not however explore responses to the dark experimental conditions in assemblages of several taxa...

  4. Recent Advances in Outdoor High-Density Cultivation of Novelty Micro-Algae Strain with High Content of Lipids

    OpenAIRE

    Kaštánek, Petr

    2012-01-01

    The objective of the study was the pilot plant examination of a newly developed integrated process for autotrophic cultivation of useful micro-algae. The process utilizes waste carbon dioxide as a source of carbon and yields simultaneously products that can be utilized in food and cosmetic industries, turned into biodiesel and/or used as a supplement in animal feed. At present, the cultivation of micro-algae merely for the production of biofuels is not economically viable. In the proposed pr...

  5. Quantitative analysis of an engineered CO2-fixing Escherichia coli reveals great potential of heterotrophic CO2 fixation

    OpenAIRE

    Gong, Fuyu; Liu, Guoxia; Zhai, Xiaoyun; Zhou, Jie; Cai, Zhen; Yin LI

    2015-01-01

    Background Production of fuels from the abundant and wasteful CO2 is a promising approach to reduce carbon emission and consumption of fossil fuels. Autotrophic microbes naturally assimilate CO2 using energy from light, hydrogen, and/or sulfur. However, their slow growth rates call for investigation of the possibility of heterotrophic CO2 fixation. Although preliminary research has suggested that CO2 fixation in heterotrophic microbes is feasible after incorporation of a CO2-fixing bypass int...

  6. Hydrogen isotopic compositions of organic compounds in plants reflect the plant's carbon metabolism

    Science.gov (United States)

    Cormier, M. A.; Kahmen, A.; Werner, R. A.

    2015-12-01

    The main factors controlling δ2H of plant organic compounds are generally assumed to be the plant's source water and the evaporative deuterium enrichment of leaf water. Hydrogen isotope analyses of plant compounds from sediments or tree rings are therefore mainly applied to assess hydrological conditions at different spatial and temporal scales. However, the biochemical hydrogen isotope fractionation occurring during biosynthesis of plant organic compounds (ɛbio) also accounts for a large part of the variability observed in the δ2H values. Nevertheless, only few studies have directly addressed the physiological basis of this variability and even fewer studies have thus explored possible applications of hydrogen isotope variability in plant organic compounds for plant physiological research. Here we show two datasets indicating that the plant's carbon metabolism can have a substantial influence on δ2H values of n-alkanes and cellulose. First, we performed a controlled experiment where we forced plants into heterotrophic and autotrophic C-metabolism by growing them under four different light treatments. Second, we assessed the δ2H values of different parasitic heterotrophic plants and their autotrophic host plants. Our two datasets show a systematic shift in ɛbio of up to 80 ‰ depending on the plant's carbon metabolism (heterotrophic or autotrophic). Differences in n-alkane and cellulose δ2H values in plants with autotrophic vs. heterotrophic metabolisms can be explained by different NADPH pools that are used by the plants to build their compounds either with assimilates that originate directly from photosynthesis or from stored carbohydrates. Our results have significant implications for the calibration and interpretation of geological records. More importantly, as the δ2H values reflect the plant's carbon metabolism involved during the tissue formation, our findings highlight the potential of δ2H values as new tool for studying plant and ecosystem carbon

  7. 2012 Molecular Basis of Microbial One-Carbon Metabolism Gordon Research Conferences and Gordon Research Seminar, August 4-10,2012

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Thomas

    2012-08-10

    The 2012 Gordon Conference will present and discuss cutting-edge research in the field of microbial metabolism of C1 compounds. The conference will feature the roles and application of C1 metabolism in natural and synthetic systems at scales from molecules to ecosystems. The conference will stress molecular aspects of the unique metabolism exhibited by autotrophic bacteria, methanogens, methylotrophs, aerobic and anaerobic methanotrophs, and acetogens.

  8. Genetic engineering of cyanobacteria

    DEFF Research Database (Denmark)

    Jacobsen, Jacob Hedemand

    , including genetic tools that allow metabolic engineering. The cyanobacterial phylum represents a diverse group of aerobic photosynthetic bacteria that are widespread in nature. Cyanobacteria shaped our atmosphere by oxygen evolution through the splitting of water using energy from sunlight. The sole carbon...... source for growth in autotrophic cyanobacteria is CO2, which is reduced to carbohydrates during photosynthesis. Simple input requirements, fast growth rates and tolerance of adverse environmental conditions make cyanobacteria attractive candidates for large scale production of energy or value added...

  9. Organisation of microbenthic communities in intertidal estuarine flats, a case study from the Molenplaat (Westerschelde Estuary, The Netherlands)

    OpenAIRE

    Hamels, I.; Sabbe, K.; Muylaert, K.; BARRANGUET, C; Lucas, A.; P. M. J. Herman; Vyverman, W.

    1998-01-01

    The auto- and heterotrophic microbenthic communities of a tidal flat in the Westerschelde estuary were studied at 4 stations in late spring and early autumn 1996. Additional information on the diatom component of these communities was obtained from a one-year survey of these organisms. Total autotrophic biomass greatly exceeded heterotrophic biomass in late spring, especially at the more silty stations. However, in autumn, the auto-/heterotrophic biomass ratio was much lower and is < 1 in the...

  10. Nitrogen control of 13C enrichment in heterotrophic organs relative to leaves in a landscape-building desert plant species

    OpenAIRE

    Zhang, J.; Gu, L; F. Bao; Cao, Y.; Hao, Y.; He, J.; Li, J.; Li, Y.; Ren, Y.; Wang, F.; Wu, R; B. Yao; Zhao, Y.; Lin, G.; Wu, B

    2014-01-01

    A longstanding puzzle in isotope studies of C3 plant species is that heterotrophic plant organs (e.g., stems, roots, seeds, and fruits) tend to be enriched in 13C compared to the autotrophic organ (leaves) that provides them with photosynthate. Our inability to explain this puzzle suggests key deficiencies in understanding post-photosynthetic metabolic processes. It also limits the effectiveness of applications of stable carbon isotope analyses in a variety of scientific dis...

  11. Nitrogen control of 13C enrichment in heterotrophic organs relative to leaves in a landscape-building desert plant species

    OpenAIRE

    Zhang, J.; Gu, L; F. Bao; Cao, Y.; Hao, Y.; He, J.; Li, J.; Li, Y.; Ren, Y.; Wang, F.; Wu, R; B. Yao; Zhao, Y.; Lin, G.; Wu, B

    2015-01-01

    A longstanding puzzle in isotope studies of C3 plant species is that heterotrophic plant organs (e.g., stems, roots, seeds, and fruits) tend to be enriched in 13C compared to the autotrophic organ (leaves) that provides them with photosynthate. Our inability to explain this puzzle suggests key deficiencies in understanding post-photosynthetic metabolic processes. It also limits the effectiveness of applications of stable carbon isotope analyses in a variety of scientific dis...

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

    Energy Technology Data Exchange (ETDEWEB)

    Beller, H R

    2004-06-25

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

  13. Whole-genome sequencing reveals novel insights into sulfur oxidation in the extremophile Acidithiobacillus thiooxidans

    OpenAIRE

    Yin, Huaqun; Zhang, Xian; Li, Xiaoqi; He, Zhili; Liang, Yili; Guo, Xue; Hu, Qi; Xiao, Yunhua; Cong, Jing; Ma, Liyuan; Niu, Jiaojiao; Liu, Xueduan

    2014-01-01

    Background Acidithiobacillus thiooxidans (A. thiooxidans), a chemolithoautotrophic extremophile, is widely used in the industrial recovery of copper (bioleaching or biomining). The organism grows and survives by autotrophically utilizing energy derived from the oxidation of elemental sulfur and reduced inorganic sulfur compounds (RISCs). However, the lack of genetic manipulation systems has restricted our exploration of its physiology. With the development of high-throughput sequencing techno...

  14. Does B12 vitamin limit phytoplankton growth in the new Iberian Peninsula?

    OpenAIRE

    Esther Barber Lluch

    2014-01-01

    The effects of increasing nutrient inputs entering to oceanic and coastal environments on primary producers are hardly predictable. Phytoplankton responses to nutrient supply depend on the autotrophic-heterotrophic coupling and a profound understanding of this interaction is required to describe response patterns. A series of microcosm experiments were carried out to assess the response of primary producers to nutrient amendments and to elucidate the role of B-vitamins on phytoplankton growth...

  15. Temperature effect on aerobic denitrification and nitrification

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-guang; ZHANG Xiao-jian; WANG Zhan-sheng

    2003-01-01

    Nitrogen loss without organic removal in biofilter was observed and its possible reason was explained. A lower hydraulic loading could improve aerobic denitrification rate. Aerobic denitrification was seriously affected by low temperature(below 10oC). However, nitrification rate remained high when the temperature dropped from 15oC to5oC. It seemed the autotrophic biofilm in BAF could alleviate the adverse effect of low temperature.

  16. Nitrification in acid coniferous forests: Some soils do, some soils don't

    OpenAIRE

    Nugroho, R.A.

    2006-01-01

    Nitrification is a key process in the global nitrogen cycle. Ammonia-oxidising bacteria (AOB) were long thought to be the sole microorganisms capable of autotrophic ammonia oxidation, the rate-limited step in nitrification. This thesis elucidates the relation between the presence of AOB, environmental factors and nitrification rates in the soil layer of acid coniferous forests. Especially, the question why some acid forests show nitrification while others do not, is addressed in this thesis.

  17. Which Environmental Factors Predict Seasonal Variation in the Coral Health of Acropora digitifera and Acropora spicifera at Ningaloo Reef?

    OpenAIRE

    Hinrichs, Saskia; Patten, Nicole L.; Feng, Ming; Strickland, Daniel; Waite, Anya M.

    2013-01-01

    The impact of physico-chemical factors on percent coral cover and coral health was examined on a spatial basis for two dominant Acropora species, A. digitifera and A. spicifera, at Ningaloo Reef (north-western Australia) in the southeast Indian Ocean. Coral health was investigated by measuring metabolic indices (RNA/DNA ratio and protein concentration), energy levels (lipid ratio) and autotrophic indices (chlorophyll a (chl a) and zooxanthellae density) at six stations during typical seasons ...

  18. Inter-annual ciliate distribution variation within the late stratification oxycline in a monomictic lake, Lake Alchichica (Mexico)

    OpenAIRE

    Ximena Sánchez Medina; Miroslav Macek; Fernando Bautista-Reyes; Andrea Perz; Patricia Bonilla Lemus; Mario Chávez Arteaga

    2016-01-01

    noxia, and ciliates might play a very important role in the plankton community budget there. We analysed changes in the composition and biomass of the ciliate assemblage and other microbial loop components throughout the oxycline just at the end of stratification in a warm-monomictic lake, Lake Alchichica, Mexico (four samplings: 2006-2008, 2010); the results were compared with those obtained from another lake from the region, La Preciosa, sampled in 2010. Bacteria, autotrophic picoplankton (...

  19. Mass-energy balance analysis for estimation of light energy conversion in an integrated system of biological H2 production

    OpenAIRE

    A.I. Gavrisheva; B.F. Belokopytov; V.I. Semina; E.S. Shastik; T.V. Laurinavichene; A.A. Tsygankov

    2015-01-01

    The present study investigated an integrated system of biological H2 production, which includes the accumulation of biomass of autotrophic microalgae, dark fermentation of biomass, and photofermentation of the dark fermentation effluent. Particular emphasis was placed on the estimation of the conversion efficiency of light into hydrogen energy at each stage of this system. For this purpose, the mass and energy balance regularities were applied. The efficiency of the energy transformation from...

  20. Whole-Cell Protein Profiles of Disintegrated Freshwater Green Algae and Cyanobacterium

    OpenAIRE

    Samek, Dušan; Mišurcová, Ladislava; Machů, Ludmila; Buňková, Leona; Minařík, Antonín; Fišera, Miroslav

    2016-01-01

    The influence of cultivation methods and postharvesting treatment on protein profiles of green freshwater microalgae Chlorella kessleri, Scenedesmus quadricauda, and Chlorella sp. and cyanobacterium Spirulina platensis were evaluated. The comparison of protein profiles in algal biomass originated from the autotrophic cultivation in an outdoor open circulating cascade-type cultivation apparatus in thin-layer, a solar photobioreactor, and from the heterotrophic cultivation regime in a fermenter...

  1. Ammonia-oxidizing archaea have more important role than ammonia-oxidizing bacteria in ammonia oxidation of strongly acidic soils

    OpenAIRE

    Zhang, Li-Mei; Hu, Hang-Wei; Shen, Ju-Pei; He, Ji-Zheng

    2011-01-01

    Increasing evidence demonstrated the involvement of ammonia-oxidizing archaea (AOA) in the global nitrogen cycle, but the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to ammonia oxidation are still in debate. Previous studies suggest that AOA would be more adapted to ammonia-limited oligotrophic conditions, which seems to be favored by protonation of ammonia, turning into ammonium in low-pH environments. Here, we investigated the autotrophic nitrification activity of AOA...

  2. The ammonia monooxygenase structural gene amoA as a functional marker: molecular fine-scale analysis of natural ammonia-oxidizing populations.

    OpenAIRE

    Rotthauwe, J H; K. P. WITZEL; Liesack, W.

    1997-01-01

    The naturally occurring genetic heterogeneity of autotrophic ammonia-oxidizing populations belonging to the beta subclass of the Proteobacteria was studied by using a newly developed PCR-based assay targeting a partial stretch of the gene which encodes the active-site polypeptide of ammonia monooxygenase (amoA). The PCR yielded a specific 491-bp fragment with all of the nitrifiers tested, but not with the homologous stretch of the particulate methane monooxygenase, a key enzyme of methane-oxi...

  3. High-Throughput Analysis of Ammonia Oxidiser Community Composition via a Novel, amoA-Based Functional Gene Array

    OpenAIRE

    Guy C J Abell; Stan S Robert; Frampton, Dion M. F.; John K Volkman; Farhan Rizwi; József Csontos; Levente Bodrossy

    2012-01-01

    Advances in microbial ecology research are more often than not limited by the capabilities of available methodologies. Aerobic autotrophic nitrification is one of the most important and well studied microbiological processes in terrestrial and aquatic ecosystems. We have developed and validated a microbial diagnostic microarray based on the ammonia-monooxygenase subunit A (amoA) gene, enabling the in-depth analysis of the community structure of bacterial and archaeal ammonia oxidisers. The am...

  4. Treatment of High-Strength Nitrogen Wasetewater With a Hollow-Fiber Membrane-Aerated Biofilm Reactor: A Comprehensive Evaluation

    OpenAIRE

    Gilmore, Kevin R

    2008-01-01

    Protecting the quality and quantity of our water resources requires advanced treatment technologies capable of removing nutrients from wastewater. This research work investigated the capability of one such technology, a hollow-fiber membrane-aerated biofilm reactor (HFMBR), to achieve completely autotrophic nitrogen removal from a wastewater with high nitrogen content. Because the extent of oxygenation is a key parameter for controlling the metabolic processes that occur in a wastewate...

  5. Vascular gene expression: a hypothesis

    OpenAIRE

    Martínez-Navarro, Angélica C.; Galván-Gordillo, Santiago V.; Xoconostle-Cázares, Beatriz; Ruiz-Medrano, Roberto

    2013-01-01

    The phloem is the conduit through which photoassimilates are distributed from autotrophic to heterotrophic tissues and is involved in the distribution of signaling molecules that coordinate plant growth and responses to the environment. Phloem function depends on the coordinate expression of a large array of genes. We have previously identified conserved motifs in upstream regions of the Arabidopsis genes, encoding the homologs of pumpkin phloem sap mRNAs, displaying expression in vascular ti...

  6. Utilización de glucosa por Prochlorococcus: caracterización del transportador Pro 1404 y efectos metabólicos

    OpenAIRE

    Muñoz Marín, Mª Carmen

    2013-01-01

    Prochlorococcus is responsible for a significant part of CO2 fixation in the ocean. It was long considered an autotrophic cyanobacterium, but our group has shown in laboratory experiments that Prochlorococcus can take up glucose like a heterotrophic organism. However, the mechanisms of glucose uptake and its occurrence in the ocean have not been shown. Here we report that the gene melB confers capability for glucose uptake in P. marinus SS120. We utilized a cyanobacterium un...

  7. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya)

    OpenAIRE

    Nyunja, J.; Ntiba, M.; Onyari, J.; Mavuti, K.; K. Soetaert; BOUILLON, S

    2009-01-01

    Interlinked mangrove-seagrass ecosystems are characteristic features of many tropical coastal areas, where they act as feeding and nursery grounds for a variety of fishes and invertebrates. The autotrophic carbon sources supporting fisheries in Gazi bay (Kenya) were studied in three sites, two located in the tidal creeks flowing through extensive mangrove forests, another site located in the subtidal seagrass meadows, approximately 2.5 km away from the forest. Carbon and nitrogen stable isoto...

  8. Evolution of Microbial “Streamer” Growths in an Acidic, Metal-Contaminated Stream Draining an Abandoned Underground Copper Mine

    OpenAIRE

    D. Barrie Johnson; Hallberg, Kevin B.; Laura Rocchetti; Kris Coupland; Rowe, Owen F.; Catherine M. Kay

    2013-01-01

    A nine year study was carried out on the evolution of macroscopic “acid streamer” growths in acidic, metal-rich mine water from the point of construction of a new channel to drain an abandoned underground copper mine. The new channel became rapidly colonized by acidophilic bacteria: two species of autotrophic iron-oxidizers (Acidithiobacillus ferrivorans and “Ferrovum myxofaciens”) and a heterotrophic iron-oxidizer (a novel genus/species with the propos...

  9. Deammonification in the moving-bed process for the treatment of wastewater with high ammonia content

    Energy Technology Data Exchange (ETDEWEB)

    Rosenwinkel, K.H.; Cornelius, A. [Institut fuer Siedlungswasserwirtschaft und Abfalltechnik der Universitaet Hannover (ISAH), Welfengarten 1, D-30167 Hannover (Germany)

    2005-01-01

    The process of deammonification for the biological treatment of sludge water was investigated in a full-scale pilot plant at Hattingen, Germany. Since deammonification is a completely autotrophic process, no organic carbon is needed for bacteria growth. So, deammonification is an attractive and cost-effective process for the treatment of wastewater with unfavorable COD/N ratio without using an external carbon source. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  10. Nanoscale analysis of pyritized microfossils reveals differential heterotrophic consumption in the ∼1.9-Ga Gunflint chert

    OpenAIRE

    Wacey, David.; McLoughlin, Nicola; Kilburn, Matt R; Saunders, Martin; Cliff, John B.; KONG, Charlie; Barley, Mark E.; MARTIN D. BRASIER

    2013-01-01

    The 1.88-Ga Gunflint biota is one of the most famous Precambrian microfossil lagerstätten and provides a key record of the biosphere at a time of changing oceanic redox structure and chemistry. Here, we report on pyritized replicas of the iconic autotrophic Gunflintia–Huroniospora microfossil assemblage from the Schreiber Locality, Canada, that help capture a view through multiple trophic levels in a Paleoproterozoic ecosystem. Nanoscale analysis of pyritic Gunflintia (sheaths) and Huroniospo...

  11. Seagrass systems : stability of seagrass systems against anthropogenic impacts

    OpenAIRE

    Munkes, Britta

    2005-01-01

    The study presented here examines which factors directly or indirectly connected to eutrophication, are relevant to the deterioration of seagrass populations in the Baltic Sea/Greifswalder Bodden. More particularly it is a study of the interaction effects of seagrass autotrophic competitors (epiphytic algae, drifting macroalgae and phytoplankton) on seagrass. These are interesting yet largely studied and were, in this study, investigated through the field observations and experiments of a sea...

  12. Induction of differentiation in the shoot apical meristem by transient overexpression of a retinoblastoma-related protein

    OpenAIRE

    Wyrzykowska, Joanna; Schorderet, Martine; Pien, Stéphane; Gruissem, Wilhelm; Fleming, Andrew J.

    2007-01-01

    The shoot apical meristem contains cells that undergo continual growth and division to generate the building blocks for the aerial portion of the plant. As cells leave the meristem, they undergo differentiation to form specific cell types. Most notably, heterotrophic cells of the meristem rapidly gain autotrophic capability by synthesis and assembly of components of the chloroplast. At the same time, cells undergo enlargement via vacuolation. Despite significant advances in the characterizati...

  13. Biomedical and Environmental Support programs

    International Nuclear Information System (INIS)

    Progress is reported on studies on the effects of heat, ionizing radiation, and various combinations of the two on the inactivation of hepatitis viruses in various environments such as blood and sewage sludge. The mutational effects of heat, radiation, and combinations thereof on spore-forming bacteria are being studied and preliminary results are reported from a study of the frequency of autotrophic mutants observed among the survivors of Bacillus subtilis spores after varying periods of dry-heat treatment. (CH)

  14. European seaweeds under pressure: Consequences for communities and ecosystem functioning

    OpenAIRE

    Mineur, F.; Arenas, F.; Assis, J.; Davies, A J; Engelen, A. H.; Fernandes, F; Malta, E.-J.; T. THIBAUT; Nguyen, T.; Vaz-Pinto, F.; Vranken, S.; Serrão, E.A.; De Clerck, O.

    2015-01-01

    Seaweed assemblages represent the dominant autotrophic biomass in many coastal environments, playing a central structural and functional role in several ecosystems. In Europe, seaweed assemblages are highly diverse systems. The combined seaweed flora of different European regions hold around 1550 species (belonging to nearly 500 genera), with new species continuously uncovered, thanks to the emergence of molecular tools. In this manuscript we review the effects of global and local stressors o...

  15. Innovative process scheme for removal of organic matter, phosphorus and nitrogen from pig manure

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Schmidt, Jens Ejbye; Angelidaki, Irini

    2008-01-01

    blanket (UASB) reactor, partial oxidation), nitrogen (oxygen-limited autotrophic nitrification-denitrification, OLAND) and phosphorus (phosphorus removal by precipitation as struvite, PRS) from pig manure were tested. Results obtained showed that microfiltration was unsuitable for pig manure treatment...... with sequential separation by decanter centrifuge, post-digestion in UASB reactor, partial oxidation and finally OLAND process. This combination resulted in reduction of the total organic, nitrogen and phosphorus contents by 96%, 88%, and 81%, respectively....

  16. Fatty Acids as a Tool to Understand Microbial Diversity and Their Role in Food Webs of Mediterranean Temporary Ponds

    OpenAIRE

    Carla C. C. R. de Carvalho; Maria-José Caramujo

    2014-01-01

    Temporary Mediterranean ponds are complex ecosystems which support a high diversity of organisms that include heterotrophic microorganisms, algae, crustaceans, amphibians and higher plants, and have the potential to supply food and a resting place to migratory birds. The role of heterotrophs at the base of the food web in providing energy to the higher trophic levels was studied in temporary ponds in Central and Southern Portugal. The relative quantification of the hetero and autotrophic bio...

  17. Appraisal of the tire derived rubber (TDR) medium for wastewater treatment under aerobic and anaerobic conditions

    OpenAIRE

    Naz, I; Khatoon, N; Ali, M.; Saroj, DP; S. Batool; Ali, N.; Ahmed, S.

    2013-01-01

    The present study evaluated the effectiveness and durability of TDR for biofilm development and related long term usage in fixed biofilm reactors for wastewater treatment. TDR incubated (30±2ºC) with activated sludge showed comparatively higher biofilm development (0.51g) under aerobic than under anaerobic (0. 42g) conditions after 7 weeks. During biofilm succession, a significant shift in bacterial community was observed from pathogenic to autotrophic after 4 weeks. The decreasing bacterial ...

  18. Changes in biogenic carbon flow in response to sea surface warming

    OpenAIRE

    Wohlers, Julia; Engel, Anja; Zöllner, Eckart; Breithaupt, Petra; Jürgens, K.; Hoppe, Hans-Georg; Sommer, Ulrich; Riebesell, Ulf

    2009-01-01

    The pelagic ocean harbors one of the largest ecosystems on Earth. It is responsible for approximately half of global primary production, sustains worldwide fisheries, and plays an important role in the global carbon cycle. Ocean warming caused by anthropogenic climate change is already starting to impact the marine biota, with possible consequences for ocean productivity and ecosystem services. Because temperature sensitivities of marine autotrophic and heterotrophic processes differ greatly,...

  19. Modelling and control design for SHARON/Anammox reactor sequence

    OpenAIRE

    Valverde Perez, Borja; Mauricio Iglesias, Miguel; Sin, Gürkan

    2012-01-01

    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work presents a complete model of the SHARON/Anammox reactor sequence. The dynamics of the reactor were explored pointing out the different scales of the rates in the system: slow microbial metabolism against fast chemical reaction and mass transfer. Likewise, the analysis of the dynamics contributed to establish qualitatively the requirements for control of the reactors, both for regulation...

  20. Microalgae for biofuels: the Portuguese experience

    OpenAIRE

    L. de Gouveia; Reis, Alberto; Moura, Patrícia; A. C. OLIVEIRA; Gírio, Francisco M.

    2015-01-01

    Autotrophic microalgae are photosynthetic organisms that undergo the conversion of light into chemical energy as a form of a wide range of organic compounds through its photosynthetic machinery. The cultivation of microalgae brings environmental advantages, bearing in mind the capability of nutrient recycling in wastewaters together with the fixation of greenhouse gases such as CO2. These micro-organisms have been widely recognized as having huge potential as feedstock for food, feed, pharmac...

  1. Dinoflagellates in a mesotrophic, tropical environment influenced by monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    DeCosta, P.M.; Anil, A.C.; Patil, J.S.; Hegde, S.; DeSilva, M.S.; Chourasia, M.

    -Variate Statistical Package program version 3.1(Kovach, 1998). Dinoflagellates were classified into autotrophic and heterotrophic forms based on the presence/absence of chloroplasts. They were also classified into groups based on the order to which they belong... higher in near bottom waters (39% of the vegetative dinoflagellate community) compared to surface waters (19%) during post-monsoon II (Fig. 5). 3.5 Effect of environmental variables on vegetative cells and cysts of dinoflagellates CCA station...

  2. Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

    OpenAIRE

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (R A) and heterotrophic (R H) in total soil (R T) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, ne...

  3. Structural relationships among vegetation, soil fauna and humus form in a subalpine forest ecosystem: a Hierarchical Multiple Factor Analysis (HMFA)

    OpenAIRE

    Bernier, Nicolas; F. Gillet

    2012-01-01

    Aboveground vegetation, four belowground fauna groups and humus composition have been analyzed in order to investigate the links between autotrophic and heterotrophic communities in a Norway-spruce mountain forest in Tours-en-Savoie (France). The aboveground plant community was recorded in small patches corresponding to contrasting microhabitats. Animal communities and humus layers were sampled within the same patches. The relationships between humus profile, faunistic and floristic compositi...

  4. Separating soil respiration components with stable isotopes: natural abundance and labelling approaches

    OpenAIRE

    Braig E; Tupek B

    2010-01-01

    Due to the potential of forest ecosystems contributing to CO2 increase as well as to climate change mitigation, forest-atmosphere CO2 exchange has been intensively studied over last decades. However, the contribution of individual components of belowground carbon pools is still poorly known. In particular, there is no unequivocal means to separate root respiration (autotrophic) from heterotrophic respiration by soil microflora and fauna. Most studies investigating soil respiration disturbed t...

  5. Chemosymbiotic species from the Gulf of Cadiz

    OpenAIRE

    Rodrigues, C. F.; A. Hilário; M. R. Cunha

    2013-01-01

    Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin) revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S) and investigate the intra-specific variation of isotope signat...

  6. Molecular genetics of Thiobacillus ferrooxidans.

    OpenAIRE

    Rawlings, D E; Kusano, T

    1994-01-01

    Thiobacillus ferrooxidans is a gram-negative, highly acidophilic (pH 1.5 to 2.0), autotrophic bacterium that obtains its energy through the oxidation of ferrous iron or reduced inorganic sulfur compounds. It is usually dominant in the mixed bacterial populations that are used industrially for the extraction of metals such as copper and uranium from their ores. More recently, these bacterial consortia have been used for the biooxidation of refractory gold-bearing arsenopyrite ores prior to the...

  7. Comparative analysis of microbial community between different cathode systems of microbial fuel cells for denitrification.

    Science.gov (United States)

    Li, Chao; Xu, Ming; Lu, Yi; Fang, Fang; Cao, Jiashun

    2016-03-01

    Two types of cathodic biofilm in microbial fuel cells (MFC) were established for comparison on their performance and microbial communities. Complete autotrophic simultaneous nitrification and denitrification (SND) without organics addition was achieved in nitrifying-MFC (N-MFC) with a total nitrogen (TN) removal rate of 0.35 mg/(L·h), which was even higher than that in denitrifying-MFC (D-MFC) at same TN level. Integrated denaturing gradient gel electrophoresis analysis based on both 16S rRNA and nirK genes showed that Alpha-, Gammaproteobacteria were the main denitrifier communities. Some potential autotrophic denitrifying bacteria which can use electrons and reducing power from cathodes, such as Shewanella oneidensis, Shewanella loihica, Pseudomonas aeruginosa, Starkeya novella and Rhodopseudomonas palustris were identified and selectively enriched on cathode biofilms. Further, relative abundance of denitrifying bacteria characterized by nirK/16S ratios was much higher in biofilm than suspended sludge according to real-time polymerase chain reaction. The highest enrichment efficiency for denitrifiers was obtained in N-MFC cathode biofilms, which confirmed autotrophic denitrifying bacteria enrichment is the key factor for a D-MFC system. PMID:26278100

  8. Evaluating simultaneous chromate and nitrate reduction during microbial denitrification processes.

    Science.gov (United States)

    Peng, Lai; Liu, Yiwen; Gao, Shu-Hong; Chen, Xueming; Ni, Bing-Jie

    2016-02-01

    Sulfur-based autotrophic denitrification and heterotrophic denitrification have been demonstrated to be promising technological processes for simultaneous removal of nitrate NO3(-) and chromate (Cr (VI)), two common contaminants in surface and ground waters. In this work, a mathematical model was developed to describe and evaluate the microbial and substrate interactions among sulfur oxidizing denitrifying organism, methanol-based heterotrophic denitrifiers and chromate reducing bacteria in the biofilm systems for simultaneous nitrate and chromate removal. The concomitant multiple chromate reduction pathways by these microbes were taken into account in this model. The validity of the model was tested using experimental data from three independent biofilm reactors under autotrophic, heterotrophic and mixotrophic conditions. The model sufficiently described the nitrate, chromate, methanol, and sulfate dynamics under varying conditions. The modeling results demonstrated the coexistence of sulfur-oxidizing denitrifying bacteria and heterotrophic denitrifying bacteria in the biofilm under mixotrophic conditions, with chromate reducing bacteria being outcompeted. The sulfur-oxidizing denitrifying bacteria substantially contributed to both nitrate and chromate reductions although heterotrophic denitrifying bacteria dominated in the biofilm. The mixotrophic denitrification could improve the tolerance of autotrophic denitrifying bacteria to Cr (VI) toxicity. Furthermore, HRT would play an important role in affecting the microbial distribution and system performance, with HRT of higher than 0.15 day being critical for a high level removal of nitrate and chromate (over 90%). PMID:26619398

  9. Microbial community of granules in expanded granular sludge bed reactor for simultaneous biological removal of sulfate, nitrate and lactate.

    Science.gov (United States)

    Chen, Chuan; Ren, Nanqi; Wang, Aijie; Yu, Zhenguo; Lee, Duu-Jong

    2008-07-01

    This study studied the cultivation of granules from an expanded granular sludge bed reactor that simultaneously transforms sulfates, nitrates, and oxygen to elementary sulfur, nitrogen gas, and carbon dioxides, respectively. The living cells accumulate at the granule outer layers, as revealed by the multicolor staining and confocal laser scanning microscope technique. The microbial community comprises sulfate-reducing bacteria (SRB, Desulfomicrobium sp.), heterotrophic (Pseudomonas aeruginosa and Sulfurospirillum sp.), and autotrophic denitrifiers (Sulfurovum sp. and Paracoccus denitrificans) whose population dynamics at different sulfate and nitrate loading rates are monitored with the single-strand conformation polymorphism and denaturing gradient gel electrophoresis technique. The Desulfomicrobium sp. presents one of the dominating strains following reactor startup. At high sulfate and nitrate loading rates, the heterotrophic denitrifiers overcompete autotrophic denitrifiers to reduce SRB activities. Conversely, suddenly reducing nitrate loading rates completely removes the heterotrophic denitrifier Sulfurospirillum sp. from the granules and activates the autotrophic denitrifiers. The physical fixation of different groups of functional strains in granules fine-tunes the strains' activities, and hence the reactor performance. PMID:18483736

  10. Comparative proteomics of leaves found at different stem positions of maize seedlings.

    Science.gov (United States)

    Chen, Yi-Bo; Wang, Dan; Ge, Xuan-Liang; Zhao, Biligen-Gaowa; Wang, Xu-Chu; Wang, Bai-Chen

    2016-07-01

    To better understand the roles of leaves at different stem positions during plant development, we measured the physiological properties of leaves 1-4 on maize seedling stems, and performed a proteomics study to investigate the differences in protein expression in the four leaves using two-dimensional difference gel electrophoresis and tandem mass spectrometry in conjunction with database searching. A total of 167 significantly differentially expressed protein spots were found and identified. Of these, 35% are involved in photosynthesis. By further analysis of the data, we speculated that in leaf 1 the seedling has started to transition from a heterotroph to an autotroph, development of leaf 2 is the time at which the seedling fully transitions from a heterotroph to an autotroph, and leaf maturity was reached only with fully expanded leaves 3 and 4, although there were still some protein expression differences in the two leaves. These results suggest that the different leaves make different contributions to maize seedling growth via modulation of the expression of the photosynthetic proteins. Together, these results provide insight into the roles of the different maize leaves as the plant develops from a heterotroph to an autotroph. PMID:27176136

  11. Soil CO2 efflux in an old-growth southern conifer forest (Agathis australis) - magnitude, components and controls

    Science.gov (United States)

    Schwendenmann, Luitgard; Macinnis-Ng, Cate

    2016-08-01

    Total soil CO2 efflux and its component fluxes, autotrophic and heterotrophic respiration, were measured in a native forest in northern Aotearoa-New Zealand. The forest is dominated by Agathis australis (kauri) and is on an acidic, clay rich soil. Soil CO2 efflux, volumetric soil water content and soil temperature were measured bi-weekly to monthly at 72 sampling points over 18 months. Trenching and regression analysis was used to partition total soil CO2 efflux into heterotrophic and autotrophic respiration. The effect of tree structure was investigated by calculating an index of local contribution (Ic, based on tree size and distance to the measurement location) followed by correlation analysis between Ic and total soil CO2 efflux, root biomass, litterfall and soil characteristics. The measured mean total soil CO2 efflux was 3.47 µmol m-2 s-1. Autotrophic respiration accounted for 25 % (trenching) or 28 % (regression analysis) of total soil CO2 efflux. Using uni- and bivariate models showed that soil temperature was a poor predictor of the temporal variation in total soil CO2 efflux (soil CO2 efflux, root biomass and mineral soil CN ratio within 5-6 m of the sampling points. Using multiple regression analysis revealed that 97 % of the spatial variability in total soil CO2 efflux in this kauri-dominated stand was explained by root biomass and soil temperature. Our findings suggest that biotic factors such as tree structure should be investigated in soil carbon related studies.

  12. Synthetic Biology of Cyanobacteria: Unique Challenges and Opportunities

    Directory of Open Access Journals (Sweden)

    Bertram M Berla

    2013-08-01

    Full Text Available Photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. Synthetic biology tools can help unlock cyanobacteria’s potential for these functions, but unfortunately tool development for these organisms has lagged behind that for S. cerevisiae and E. coli. While these organisms may in many cases be more difficult to work with as ‘chassis’ strains for synthetic biology than certain heterotrophs, the unique advantages of autotrophs in biotechnology applications as well as the scientific importance of improved understanding of photosynthesis warrant the development of these systems into something akin to a ‘green E. coli’. In this review, we highlight unique challenges and opportunities for development of synthetic biology approaches in cyanobacteria. We review classical and recently developed methods for constructing targeted mutants in various cyanobacterial strains, and offer perspective on what genetic tools might most greatly expand the ability to engineer new functions in such strains. Similarly, we review what genetic parts are most needed for the development of cyanobacterial synthetic biology. Finally, we highlight recent methods to construct genome-scale models of cyanobacterial metabolism and to use those models to measure properties of autotrophic metabolism. Throughout this paper, we discuss some of the unique challenges of a diurnal, autotrophic lifestyle along with how the development of synthetic biology and biotechnology in cyanobacteria must fit within those constraints.

  13. Investigation of the combined effects of acetate and photobioreactor illuminated fraction in the induction of anoxia for hydrogen production by Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Degrenne, Benoit; Pruvost, Jeremy; Cogne, Guillaume; Legrand, Jack [Nantes Universite, CNRS, GEPEA UMR-CNRS 6144, Bd de l' Universite, CRTT-BP 406, 44602 Saint-Nazaire Cedex (France); Christophe, Gwendoline; Cornet, Jean Francois [Clermont Universite - ENSCCF, LGCB, 9 Rue Kessler, BP 10448, F-63012 Clermont-Ferrand Cedex 1 (France)

    2010-10-15

    In the context of hydrogen production by microalgae, the growth of Chlamydomonas reinhardtii was characterized under autotrophic and mixotrophic conditions in a fully controlled photobioreactor (PBR). The combined effect of light transfer conditions, as represented by the illuminated fraction {gamma}, with acetate consumption was observed upon establishment of anoxia. Anoxia was reached in batch cultures when {gamma} was close to 1 (almost fully illuminated culture) in mixotrophic conditions while a value of {gamma} {approx} 0.46 in autotrophic conditions was not sufficient. Based on these results, continuous hydrogen production was established in a cylindrical PBR operated in luminostat with constant illumination and in mixotrophic conditions. Maximum hydrogen gas production was equal to 1.4 {+-} 0.1 ml{sub H2} l{sup -1} h{sup -1} for photon flux density of 110 {mu}mol m{sup -2} s{sup -1} and reactor illuminated fraction of {gamma} = 0.5. Carbon mass balance was realized, emphasizing the necessity to work in strictly autotrophic conditions for hydrogen production with no concomitant CO{sub 2} release. (author)

  14. Improving the ISBACC land surface model simulation of water and carbon fluxes and stocks over the Amazon forest

    Science.gov (United States)

    Joetzjer, E.; Delire, C.; Douville, H.; Ciais, P.; Decharme, B.; Carrer, D.; Verbeeck, H.; De Weirdt, M.; Bonal, D.

    2015-06-01

    We evaluate the ISBACC (Interaction Soil Biosphere Atmosphere Carbon Cycle) land surface model (LSM) over the Amazon forest, and propose a revised parameterization of photosynthesis, including new soil water stress and autotrophic respiration (RA) functions. The revised version allows the model to better capture the energy, water and carbon fluxes when compared to five Amazonian flux towers. The performance of ISBACC is slightly site dependent although similar to the widely evaluated LSM ORCHIDEE (Organizing Carbon and Hydrology In Dynamic Ecosystems - version 1187), which is based on different assumptions. Changes made to the autotrophic respiration functions, including a vertical profile of leaf respiration, lead to yearly simulated carbon use efficiency (CUE) and carbon stocks which is consistent with an ecophysiological meta-analysis conducted on three Amazonian sites. Despite these major improvements, ISBACC struggles to capture the apparent seasonality of the carbon fluxes derived from the flux tower estimations. However, there is still no consensus on the seasonality of carbon fluxes over the Amazon, stressing a need for more observations as well as a better understanding of the main drivers of autotrophic respiration.

  15. Energetic differences between bacterioplankton trophic groups and coral reef resistance.

    Science.gov (United States)

    McDole Somera, Tracey; Bailey, Barbara; Barott, Katie; Grasis, Juris; Hatay, Mark; Hilton, Brett J; Hisakawa, Nao; Nosrat, Bahador; Nulton, James; Silveira, Cynthia B; Sullivan, Chris; Brainard, Russell E; Rohwer, Forest

    2016-04-27

    Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance. PMID:27097927

  16. Evolution of Microbial “Streamer” Growths in an Acidic, Metal-Contaminated Stream Draining an Abandoned Underground Copper Mine

    Directory of Open Access Journals (Sweden)

    D. Barrie Johnson

    2013-02-01

    Full Text Available A nine year study was carried out on the evolution of macroscopic “acid streamer” growths in acidic, metal-rich mine water from the point of construction of a new channel to drain an abandoned underground copper mine. The new channel became rapidly colonized by acidophilic bacteria: two species of autotrophic iron-oxidizers (Acidithiobacillus ferrivorans and “Ferrovum myxofaciens” and a heterotrophic iron-oxidizer (a novel genus/species with the proposed name “Acidithrix ferrooxidans”. The same bacteria dominated the acid streamer communities for the entire nine year period, with the autotrophic species accounting for ~80% of the micro-organisms in the streamer growths (as determined by terminal restriction enzyme fragment length polymorphism (T-RFLP analysis. Biodiversity of the acid streamers became somewhat greater in time, and included species of heterotrophic acidophiles that reduce ferric iron (Acidiphilium, Acidobacterium, Acidocella and gammaproteobacterium WJ2 and other autotrophic iron-oxidizers (Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans. The diversity of archaea in the acid streamers was far more limited; relatively few clones were obtained, all of which were very distantly related to known species of euryarchaeotes. Some differences were apparent between the acid streamer community and planktonic-phase bacteria. This study has provided unique insights into the evolution of an extremophilic microbial community, and identified several novel species of acidophilic prokaryotes.

  17. Environmental impact of heavy metals from dredged and resuspended sediments on phytoplankton and bacteria assessed in in situ mesocosms.

    Science.gov (United States)

    Nayar, S; Goh, B P L; Chou, L M

    2004-11-01

    Past and on-going reclamation, dredging, construction and shipping activities impact Ponggol Estuary, located on the northeastern coast of Singapore. Tin, lead, nickel, cadmium, and copper in particulate and dissolved fractions and sediments ranged from ND (undetectable)-92 ppm, ND-303.2 ppm, ND-2818.4 ppm, ND-74.4 ppm and ND-1117.7 ppm, respectively. Intensive dredging activity during the monitoring period may have led to the resuspension and bioavailability of particulate metals. This was tested by the exposure of phytoplankton and bacteria in mesocosms to previously measured environmental levels of heavy metals and the contaminated sediments with the highest heavy metal concentrations from one of the impacted sites. The results showed significant copper toxicity to phytoplankton and autotrophic bacteria, followed by nickel and lead at all concentrations tested. Enhanced rates of heterotrophic bacterial production and total bacterial abundance were observed in treatments with higher metal concentrations. Among the various treatments, particulate and sediment metal concentrations were significantly different from those of the control. Mesocosms using contaminated sediments with the highest metal concentrations compared with the control showed a bioavailability of metals that resulted in the inhibition of phytoplankton and autotrophic bacteria. High concentrations of copper (5.52-11.35 mg L(-1)) and nickel (2.42-2.71 mg L(-1)) observed in the aqueous phase of treatment mesocosms, and attributed to release from the contaminated sediments could account for the toxicity to phytoplankton and autotrophic bacteria. PMID:15388275

  18. Proteomic analysis of carbon concentrating chemolithotrophic bacteria Serratia sp. for sequestration of carbon dioxide.

    Directory of Open Access Journals (Sweden)

    Randhir K Bharti

    Full Text Available A chemolithotrophic bacterium enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was identified as Serratia sp. by 16S rRNA sequencing. Carbon dioxide sequestering capacity of bacterium was detected by carbonic anhydrase enzyme and ribulose-1, 5- bisphosphate carboxylase/oxygenase (RuBisCO. The purified carbonic anhydrase showed molecular weight of 29 kDa. Molecular weight of RuBisCO was 550 kDa as determined by fast protein liquid chromatography (FPLC, however, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE showed presence of two subunits whose molecular weights were 56 and 14 kDa. The Western blot analysis of the crude protein and purified sample cross reacted with RuBisCO large-subunit polypeptides antibodies showed strong band pattern at molecular weight around 56 kDa regions. Whole cell soluble proteins of Serratia sp. grown under autotrophic and heterotrophic conditions were resolved by two-dimensional gel electrophoresis and MALDI-TOF/MS for differential expression of proteins. In proteomic analysis of 63 protein spots, 48 spots were significantly up-regulated in the autotrophically grown cells; seven enzymes showed its utilization in autotrophic carbon fixation pathways and other metabolic activities of bacterium including lipid metabolisms indicated sequestration potency of carbon dioxide and production of biomaterials.

  19. Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge

    KAUST Repository

    Tian, Renmao

    2014-08-29

    Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Biogeophysical interactions control the formation of iron oxide microbial biofilms in acidic geothermal outflow channels of Yellowstone National Park

    Science.gov (United States)

    Beam, J.; Berstein, H. C.; Jay, Z.; Kozubal, M. A.; Jennings, R. D.; Inskeep, W. P.

    2012-12-01

    Amorphous iron oxyhydroxide microbial mats in acidic (pH ~ 3) geothermal outflow channels of Yellowstone National Park (YNP) are habitats for diverse populations of autotrophic and heterotrophic microorganisms from the domains Archaea and Bacteria. These systems have been extensively characterized with regards to geochemical, physical, and microbiological (e.g., metagenomics) analyses; however, there is minimal data describing the formation of these iron oxide microbial mats. A conceptual model of Fe(III)-oxide microbial mat development was created, which includes four distinct stages. Autotrophic archaea (Metallosphaera yellowstonensis) and bacteria (Hydrogenobaculum spp.) are the first colonizers (Stage I) that provide pools of organic carbon for heterotrophic thermophiles (Stage II). M. yellowstonensis is an autotrophic Sulfolobales that is responsible for the oxidation of Fe(II) and can thus be defined as the mat 'architect' creating suitable habitats for microbial niches (e.g., anaerobic microorganisms) (Stage III). The last phase of mat formation (Stage IV) represents a pseudo-steady state mature microbial mat, which has been the subject of all previous microbial surveys of these systems. The conceptual model for Fe(III)-oxide microbial mat development was tested by inserting glass (SiO2) microscope slides into the main flow channels of two acidic geothermal springs in YNP. Slides were removed at various time intervals and analyzed for total iron accretion, microbial community structure (i.e., 16S rRNA gene abundance), and mRNA expression of community members. Routine geochemical and physical (e.g., flow) parameters were also measured to decipher their relative contribution to mat development. Initial and previous results show that autotrophic microorganisms (e.g, M. yellowstonensis) are often the first to colonize the glass slides and their activity was confirmed by mRNA expression of genes related to iron oxidation and carbon fixation. Heterotrophs are rare

  1. A Numerical Study of the Effect of Periodic Nutrient Supply on Pathways of Carbon in a Coastal Upwelling Regime

    Science.gov (United States)

    Carr, Mary-Elena

    1998-01-01

    A size-based ecosystem model was modified to include periodic upwelling events and used to evaluate the effect of episodic nutrient supply on the standing stock, carbon uptake, and carbon flow into mesozooplankton grazing and sinking flux in a coastal upwelling regime. Two ecosystem configurations were compared: a single food chain made up of net phytoplankton and mesozooplankton (one autotroph and one heterotroph, A1H1), and three interconnected food chains plus bacteria (three autotrophs and four heterotrophs, A3H4). The carbon pathways in the A1H1 simulations were under stronger physical control than those of the A3H4 runs, where the small size classes are not affected by frequent upwelling events. In the more complex food web simulations, the microbial pathway determines the total carbon uptake and grazing rates, and regenerated nitrogen accounts for more than half of the total primary production for periods of 20 days or longer between events. By contrast, new production, export of carbon through sinking and mesozooplankton grazing are more important in the A1H1 simulations. In the A3H4 simulations, the turnover time scale of the autotroph biomass increases as the period between upwelling events increases, because of the larger contribution of slow-growing net phytoplankton. The upwelling period was characterized for three upwelling sites from the alongshore wind speed measured by the NASA Scatterometer (NSCAT) and the corresponding model output compared with literature data. This validation exercise for three upwelling sites and a downstream embayment suggests that standing stock, carbon uptake and size fractionation were best supported by the A3H4 simulations, while the simulated sinking fluxes are not distinguishable in the two configurations.

  2. Distribution pattern of picoplankton carbon biomass linked to mesoscale dynamics in the southern gulf of Mexico during winter conditions

    Science.gov (United States)

    Linacre, Lorena; Lara-Lara, Rubén; Camacho-Ibar, Víctor; Herguera, Juan Carlos; Bazán-Guzmán, Carmen; Ferreira-Bartrina, Vicente

    2015-12-01

    In order to characterize the carbon biomass spatial distribution of autotrophic and heterotrophic picoplankton populations linked to mesoscale dynamics, an investigation over an extensive open-ocean region of the southern Gulf of Mexico (GM) was conducted. Seawater samples from the mixed layer were collected during wintertime (February-March 2013). Picoplankton populations were counted and sorted using flow cytometry analyses. Carbon biomass was assessed based on in situ cell abundances and conversion factors from the literature. Approximately 46% of the total picoplankton biomass was composed of three autotrophic populations (Prochlorococcus, Synechococcus, and pico-eukaryotes), while 54% consisted of heterotrophic bacteria populations. Prochlorococcus spp. was the most abundant pico-primary producer (>80%), and accounted for more than 60% of the total pico-autotrophic biomass. The distribution patterns of picoplankton biomass were strongly associated with the mesoscale dynamics that modulated the hydrographic conditions of the surface mixed layer. The main features of the carbon distribution pattern were: (1) the deepening of picoplankton biomass to layers closer to the nitracline base in anticyclonic eddies; (2) the shoaling of picoplankton biomass in cyclonic eddies, constraining the autoprokaryote biomasses to the upper layers, as well as accumulating the pico-eukaryote biomass in the cold core of the eddies; and (3) the increase of heterotrophic bacteria biomass in frontal regions between counter-paired anticyclonic and cyclonic eddies. Factors related to nutrient preferences and light conditions may as well have contributed to the distribution pattern of the microbial populations. The findings reveal the great influence of the mesoscale dynamics on the distribution of picoplankton populations within the mixed layer. Moreover, the significance of microbial components (especially Prochlorococcus) in the southern GM during winter conditions was revealed

  3. Photosynthetic response of Persian Gulf acroporid corals to summer versus winter temperature deviations

    Directory of Open Access Journals (Sweden)

    Jahangir Vajed Samiei

    2015-06-01

    Full Text Available With on-going climate change, coral susceptibility to thermal stress constitutes a central concern in reefconservation. In the Persian Gulf, coral reefs are confronted with a high seasonal variability in water temperature, and both hot and cold extremes have been associated with episodes of coral bleaching and mortality. Using physiological performance as a measure of coral health, we investigated the thermal susceptibility of the common acroporid, Acropora downingi, near Hengam Island where the temperature oscillates seasonally in the range 20.2–34.2 °C. In a series of two short-term experiments comparing coral response in summer versus winter conditions, we exposed corals during each season (1 to the corresponding seasonal average and extreme temperature levels in a static thermal environment, and (2 to a progressive temperature deviation from the annual mean toward the corresponding extreme seasonal value and beyond in a dynamic thermal environment. We monitored four indictors of coral physiological performance: net photosynthesis (Pn, dark respiration (R, autotrophic capability (Pn/R, and survival. Corals exposed to warming during summer showed a decrease in net photosynthesis and ultimately died, while corals exposed to cooling during winter were not affected in their photosynthetic performance and survival. Coral autotrophic capability Pn/R was lower at the warmer thermal level within eachseason, and during summer compared to winter. Corals exposed to the maximum temperature of summer displayed Pn/R < 1, inferring that photosynthetic performance could not support basal metabolic needs under this environment. Our results suggest that the autotrophic performance of the Persian Gulf A. downingi is sensitive to the extreme temperatures endured in summer, and therefore its populations may be impacted by future increases in water temperature.

  4. N2O production pathways in the subtropical acid forest soils in China

    International Nuclear Information System (INIS)

    To date, N2O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N2O production in four subtropical acid forest soils (pH2O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N2O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N2O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N2O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N2O product ratios from nitrification. The ratio of N2O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N2O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N2O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N2O production. → While, contribution of autotrophic nitrification to N2O production was little. → Ratios of N2O-N emission from nitrification were higher than those in most previous references.

  5. Whole-system metabolism and CO2 fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean

    Directory of Open Access Journals (Sweden)

    F. Gazeau

    2005-01-01

    Full Text Available Planktonic and benthic incubations (bare and Posidonia oceanica vegetated sediments were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the Bay of Palma (Mallorca, Spain. Results showed a contrast between the planktonic compartment, which was on average near metabolic balance (−4.6±5.9 mmol O2 m-2 d-1 and the benthic compartment, which was autotrophic (17.6±8.5 mmol O2 m-2 d-1. During two cruises in March and June 2002, planktonic and benthic incubations were performed at several stations in the bay to estimate the whole-system metabolism and to examine its relationship with partial pressure of CO2 (pCO2 and apparent oxygen utilisation (AOU spatial patterns. Moreover, during the second cruise, when the residence time of water was long enough, net ecosystem production (NEP estimates based on incubations were compared, over the Posidonia oceanica meadow, to rates derived from dissolved inorganic carbon (DIC and oxygen (O2 mass balance budgets. These budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the planktonic heterotrophy in shallow waters relative to the maximum depth of the bay (55 m. This generated a horizontal gradient from autotrophic or balanced communities in the shallow seagrass-covered areas, to strongly heterotrophic communities in deeper areas of the bay. It seems therefore that, on an annual scale in the whole bay, the organic matter production by the Posidonia oceanica may not be sufficient to fully compensate the heterotrophy of the planktonic compartment, which may require external organic carbon inputs, most likely from land.

  6. Spatial and temporal variability of CO2 fluxes at the sediment-air interface in a tidal flat of a temperate lagoon (Arcachon Bay, France)

    Science.gov (United States)

    Migné, Aline; Davoult, Dominique; Spilmont, Nicolas; Ouisse, Vincent; Boucher, Guy

    2016-03-01

    This study aimed to explore the spatial and temporal variability of benthic metabolism in a temperate mesotidal lagoon. This was achieved by measuring fluxes of CO2 in static chambers during emersion, both under light and dark conditions. Three sample sites were selected according to their tidal level (upper or mid), their sediment type (sand or mud) and the presence/absence of the seagrass Zostera noltei. The three sites were investigated at three seasons (end of winter, spring and beginning of autumn). At each site and each season, three benthic chambers were used simultaneously in successive incubations over the emersion period. The sediment chlorophyll-a content varied seasonally in the upper sands (reaching 283 mg.m- 2 in spring) but not in the mid muds (averaging 142 mg m- 2 in bare muds and 186 mg m- 2 in muds covered by seagrass). The maximum sediment CO2-uptake under light was 9.89 mmol m- 2 h- 1 in the mid-bare muds, in early autumn. The maximum sediment CO2-release under darkness was 6.97 mmol m- 2 h- 1 in the mid muds covered by seagrass, in spring. Both CO2-fluxes measured in the light and in the dark increased over periods of emersion. This increase, not related to light nor temperature variations, could be explained by changes in the amount and chemistry of pore water during the air exposure of sediments. The benthic trophic state index, based on the maximum light CO2-flux versus maximum dark CO2-flux ratio, assigned to each site at each season indicated that the sediments were net autotrophic in spring in upper sands and in mid muds covered by seagrass and highly autotrophic in other cases. The most autotrophic sediments were the mid-level bare muds whatever the season. The relevance of this index is discussed compared to carbon annual budget.

  7. Exploring the Metabolic Potential of Microbial Communities in Ultra-basic Reducing Spring at The Cedars, CA: Evidence of Microbial Methanogenesis and Heterotrophic Acetogenesis

    Science.gov (United States)

    Kohl, L.; Cummings, E.; Cox, A.; Suzuki, S.; Morrrissey, L.; Lang, S. Q.; Richter, A.; Nealson, K. H.; Morrill, P. L.

    2015-12-01

    The Cedars is a complex of ultra-basic, reducing springs located in the Coastal Range Ophiolite (CA, USA), a site of present day serpentinization. Similar to other serpentinization-associated fluids, the groundwaters discharging at The Cedars contain elevated concentrations of C1-C6 alkanes and volatile organic acids (VOAs) which may originate from abiotic or thermogenic processes but can also be produced, consumed, or transformed by microbial activity. In contrast to other continental sites of serpentinization, geochemical indicators (δ13CCH4, δ2HCH4, CH4/C2-C6 alkanes) are consistent with a partial microbial origin of methane at The Cedars. These indicators, however, can provide only indirect evidence of microbial methanogenesis. To further explore the metabolic potential of the indigenous microbial communities at The Cedars, we conducted a series of microcosm experiments in which fluids and sediments collected at The Cedars were incubated with 13C labeled substrates (formate, acetate, bicarbonate, methanol) under anaerobic conditions. 13C from all amended substrates was incorporated into CH4 demonstrating that these microbial communities can convert both organic and inorganic substrates to CH4. The apparent fractionation of 13C between methane and potential substrates indicated that carbonate reduction was the dominant pathway of methanogenesis, and 16S rDNA based community profiling revealed the presence of an OTU closest related to Methanobacterium sp., an autotrophic (CO2/H2) methanogen. Concentrations of C1-C4 VOAs increased 5-fold over the course of the experiment indicating the microbial production of VOAs. This acetogenesis occurred heterotrophically as autotrophic acetogenesis can be excluded because (a) δ13C values of acetate were similar to those of inorganic carbon (inconsistent with the strong discrimination against 13C observed in autotrophic acetogenesis) and (b) no incorporation of 13C from labeled bicarbonate was into acetate was observed.

  8. Composition of microbial communities in aerosol, snow and ice samples from remote glaciated areas (Antarctica, Alps, Andes

    Directory of Open Access Journals (Sweden)

    J. Elster

    2007-06-01

    Full Text Available Taxonomical and ecological analyses were performed on micro-autotrophs (cyanobacteria and algae together with remnants of diatom valves, micro-fungi (hyphae and spores, bacteria (rod, cocci and red clusters, yeast, and plant pollen extracted from various samples: Alps snow (Mt. Blank area, Andean snow (Illimani, Bolivia, Antarctic aerosol filters (Dumont d'Urville, Terre Adélie, and Antarctic inland ice (Terre Adélie. Three methods for ice and snow sample's pre-concentration were tested (filtration, centrifugation and lyophilisation. Afterwards, cultivation methods for terrestrial, freshwater and marine microorganisms (micro-autotrophs and micro-fungi were used in combination with liquid and solid media. The main goal of the study was to find out if micro-autotrophs are commonly transported by air masses, and later stored in snow and icecaps around the world. The most striking result of this study was the absence of culturable micro-autotrophs in all studied samples. However, an unusual culturable pigmented prokaryote was found in both alpine snow and aerosol samples. Analyses of many samples and proper statistical analyses (PCA, RDA- Monte Carlo permutation tests showed that studied treatments highly significantly differ in both microbial community and biotic remnants composition F=9.33, p=0.001. In addition, GLM showed that studied treatments highly significantly differ in numbers of categories of microorganisms and remnants of biological material F=11.45, p=0.00005. The Antarctic aerosol samples were characterised by having red clusters of bacteria, the unusual prokaryote and yeasts. The high mountain snow from the Alps and Andes contained much more culturable heterotrophs. The unusual prokaryote was very abundant, as were coccoid bacteria, red clusters of bacteria, as well as yeasts. The Antarctic ice samples were quite different. These samples had higher numbers of rod bacteria and fungal hyphae. The microbial communities and

  9. Interactions between the microbial network and the organic matter in the Southern Ocean: impacts on the biological carbon pump

    OpenAIRE

    Dumont, Isabelle

    2009-01-01

    The Southern Ocean (ca. 20% of the world ocean surface) is a key place for the regulation of Earth climate thanks to its capacity to absorb atmospheric carbon dioxide (CO2) by physico-chemical and biological mechanisms. The biological carbon pump is a major pathway of absorption of CO2 through which the CO2 incorporated into autotrophic microorganisms in surface waters is transferred to deep waters. This process is influenced by the extent of the primary production and by the intensity of the...

  10. Proteomic analysis of the purple sulfur bacterium Candidatus “Thiodictyon syntrophicum” strain Cad16T isolated from Lake Cadagno

    Directory of Open Access Journals (Sweden)

    Nicola Storelli

    2014-03-01

    Full Text Available Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB. 2D-DIGE was used to monitor the global changes in the proteome of Candidatus “Thiodictyon syntrophicum” strain Cad16T both in the presence and absence of light. This study aimed to disclose details regarding the dark CO2 assimilation of the PSB, as this mechanism is often observed but is not yet sufficiently understood. Our results showed the presence of 17 protein spots that were more abundant in the dark, including three enzymes that could be part of the autotrophic dicarboxylate/4-hydroxybutyrate cycle, normally observed in archaea.

  11. Changes of communities of phytobenthos of Drevnica River - ecological condition assessment in space and time

    International Nuclear Information System (INIS)

    The study deals with a biological evaluation of water quality of the Drevnice River (Eastern Moravia) by a community of cyanobacteria and algae which are tied to the bottom substrate (e.g. mud, sand, stones). Phytobenthos, as this file of benthic autotrophic organisms is called, has a significant position among bioindicators of water quality for the ability to reflect environmental changes in a short time. The work consisted in monitoring changes in diversity of phytobenthos community and measurement of physicochemical parameters within one year. The aim was to find relations between the organisms and parameters and to determinate the current ecological status of the river. (authors)

  12. Significance of the Gunflint (Precambrian) Microflora: Photosynthetic oxygen may have had important local effects before becoming a major atmospheric gas.

    Science.gov (United States)

    Cloud, P E

    1965-04-01

    Several categories of biological microstructures 1.9+/- billion years old are here described, illustrated, and referred to a group of early thallophytes that includes the thread bacteria and the blue-green algae. These microstructures were almost surely autotrophic and in the line of evolution toward green-plant photosynthesis, if not themselves oxygen producers. Geochemical evidence has been interpreted by some to imply that the contemporaneous atmosphere was essentially anoxygenic (reducing), and by others to indicate an atmosphere rich in oxygen. These conflicting interpretations may be reconciled by a hypothesis, based on demonstrable fossil organisms, that calls for local centers of biologic oxygen generation. PMID:17773767

  13. Organic carbon and iron modulate nitrification rates in mangrove swamps of Goa, south west coast of India

    Science.gov (United States)

    Krishnan, K. P.; Loka Bharathi, P. A.

    2009-09-01

    Nitrification, fuelled by ammonium is the pivotal oxidative pathway to nitrogen cycling. In spite of its ecological significance, the factors regulating nitrification rates in the benthic realm remain poorly understood. The present study therefore examines some of the factors like ammonium, nitrite, nitrate, organic carbon, iron and manganese on down-core variability in benthic nitrification rates in two different mangrove ecosystems, one under the influence of ferromanganese ore mining (experiment) and the other relatively undisturbed (control). We hypothesize that besides organic carbon, iron could also influence the rate of nitrification. The study also contrasts the distributive pattern of autotrophic and heterotrophic nitrifiers in the two regions. The concentration of iron at the control site ranged from 1.1% to 15.1% while at the experimental site it ranged from 2.9% to 46%. The levels of organic carbon at control and experimental sites ranged from 0.02% to 6.9% and 0.1% to 6.5%, respectively. The nitrification rates at the control and experimental sites are comparable and ranged from 3.2 ± 1.2 to 18.4 ± 1.9 ng at-N g(sediment) -1 h -1 and 2.7 ± 1.5 to 18.2 ± 0.6 ng at-N g(sediment) -1 h -1, respectively. While the abundance of heterotrophic nitrifiers at both the sites ranged from 10 2-3 cells g -1 sediment, the autotrophic nitrifiers at the experimental site was higher by an order at ˜10 3 cells g -1 sediment reflecting the relatively higher refractile nature of organic carbon at the experimental site (Straus and Lamberti, 2000). Though organic carbon and nitrification rates are similar in both the sites, the underlying mechanisms governing the processes could be different. Our studies suggest that at the control site, heterotrophic nitrifiers govern nitrification rates ( r = 0.28, p < 0.05, n = 64) using organic carbon ( r = 0.32, p < 0.01, n = 64). At the experimental site, nitrification was governed more by autotrophic nitrifiers ( r = 0.43, p < 0

  14. Complete genome sequence of Acidimicrobium ferrooxidans type strain (ICPT)

    Energy Technology Data Exchange (ETDEWEB)

    Clum, Alicia; Nolan, Matt; Lang, Elke; Glavina Del Rio, Tijana; Tice, Hope; Copeland, Alex; Cheng, Jan-Fang; Lucas, Susan; Chen, Feng; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Ivanova, Natalia; Mavrommatis, Konstantinos; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Goker, Markus; Spring, Stefan; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jefferies, Cynthia C.; Chain, Patrick; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter; Lapidus, Alla

    2009-05-20

    Acidimicrobium ferrooxidans (Clark and Norris 1996) is the sole and type species of the genus, which until recently was the only genus within the actinobacterial family Acidimicrobiaceae and in the order Acidomicrobiales. Rapid oxidation of iron pyrite during autotrophic growth in the absence of an enhanced CO2 concentration is characteristic for A. ferrooxidans. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the order Acidomicrobiales, and the 2,158,157 bp long single replicon genome with its 2038 protein coding and 54 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  15. Purification and some properties of carbon monoxide dehydrogenase from Acinetobacter sp. strain JC1 DSM 3803.

    OpenAIRE

    Kim, K.S.; Ro, Y T; Kim, Y. M.

    1989-01-01

    A brown carbon monoxide dehydrogenase from CO-autotrophically grown cells of Acinetobacter sp. strain JC1, which is unstable outside the cells, was purified 80-fold in seven steps to better than 95% homogeneity, with a yield of 44% in the presence of the stabilizing agents iodoacetamide (1 mM) and ammonium sulfate (100 mM). The final specific activity was 474 mumol of acceptor reduced per min per mg of protein as determined by an assay based on the CO-dependent reduction of thionin. Methyl vi...

  16. Desulfotomaculum spp. and related Gram-positive sulfate-reducing bacteria in deep subsurface environments.

    Directory of Open Access Journals (Sweden)

    AnthonyRanchou-Peyruse

    2013-12-01

    Full Text Available Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2 and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review.

  17. MIXOTROPHIC GROWTH OF THE MICROALGAE NANNOCHLOROPSIS OCULATA (EUSTIGMATALES: MONODOPSIDACEAE ON BIOLOGICAL FISH ENSILAGE MEDIUM

    Directory of Open Access Journals (Sweden)

    Sánchez-Torres, H.

    2008-07-01

    Full Text Available Nannochloropsis oculata was grown in batch culture during 12 days until stationary phase, under constant temperature and illumination 24 h per day, using three different culture media (T1 – Guillard F/2, T2 – Yashima and T3 –biological fish ensilage. We found that N. oculata reached high cellular densities in treatment T3, although it showed low chlorophyll concentrations per biomass unit, which is inconsistent with autotrophic growth. It suggests that N. oculata could growth mixotrophically in biological fish ensilage.

  18. Comparative differential gene expression analysis of nucleus-encoded proteins for Rafflesia cantleyi against Arabidopsis thaliana

    Science.gov (United States)

    Ng, Siuk-Mun; Lee, Xin-Wei; Wan, Kiew-Lian; Firdaus-Raih, Mohd

    2015-09-01

    Regulation of functional nucleus-encoded proteins targeting the plastidial functions was comparatively studied for a plant parasite, Rafflesia cantleyi versus a photosynthetic plant, Arabidopsis thaliana. This study involved two species of different feeding modes and different developmental stages. A total of 30 nucleus-encoded proteins were found to be differentially-regulated during two stages in the parasite; whereas 17 nucleus-encoded proteins were differentially-expressed during two developmental stages in Arabidopsis thaliana. One notable finding observed for the two plants was the identification of genes involved in the regulation of photosynthesis-related processes where these processes, as expected, seem to be present only in the autotroph.

  19. Temporal dynamics of phytoplankton and heterotrophic protists at station ALOHA

    Science.gov (United States)

    Pasulka, Alexis L.; Landry, Michael R.; Taniguchi, Darcy A. A.; Taylor, Andrew G.; Church, Matthew J.

    2013-09-01

    Pico- and nano-sized autotrophic and heterotrophic unicellular eukaryotes (protists) are an important component of open-ocean food webs. To date, however, no direct measurements of cell abundance and biomass of these organisms have been incorporated into our understanding of temporal variability in the North Pacific Subtropical Gyre (NPSG). Based primarily on epifluoresence microscopy augmented with flow cytometry, we assessed the abundance and biomass of autotrophs and heterotrophic protists at Station ALOHA between June 2004 and January 2009. Autotrophic eukaryotes (A-EUKS) were more abundant in both the upper euphotic zone and deep chlorophyll maximum layer (DCML) during winter months, driven mostly by small flagellates. A higher ratio of A-EUKS to heterotrophic protists (A:H ratio) and a structural shift in A-EUKS to smaller cells during the winter suggests a seasonal minimum in grazing pressure. Although Prochlococcus spp. comprised between 30% and 50% of autotrophic biomass in both the upper and lower euphotic zone for most of the year, the community structure and seasonality of nano- and micro-phytoplankon differed between the two layers. In the upper layer, Trichodesmium spp. was an important contributor to total biomass (20-50%) in the late summer and early fall. Among A-EUKS, prymnesiophytes and other small flagellates were the dominant contributors to total biomass in both layers regardless of season (10-20% and 13-39%, respectively). Based on our biomass estimates, community composition was less seasonally variable in the DCML relative to the upper euphotic zone. In surface waters, mean estimates of C:Chl a varied with season—highest in the summer and lowest in the winter (means=156±157 and 89±32, respectively); however, there was little seasonal variability of C:Chl a in the DCML (100 m mean=29.9±9.8). Biomass of heterotrophic protists peaked in the summer and generally declined monotonically with depth without a deep maximum. Anomalous patterns

  20. Monsoon-induced changes in the size-fractionated phytoplankton biomass and production rate in the estuarine and coastal waters of southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Madhu, N.V.; Jyothibabu, R.; Balachandran, K.K.

    . R, Balachandran. K. K National Institute of Oceanography, Regional Centre, Kochi -18, India Abstract Changes in the autotrophic pico- (0.2-2µm), nano- (2-20µm) and micro- (>20µm) plankton biomass (chlorophyll a) and primary production were... phytoplankton (Chisholm, 1992), while the production of small phytoplankton (nano-) are mainly controlled by microzooplankton (cilites and flagellates) grazing (Riegman et al., 1993, Jyothibabu et al., 2006). The Cochin estuary (9° 40’ & 10° 12’N and 76° 10...

  1. Carbon dioxide emissions from an Acacia plantation on peatland in Sumatra, Indonesia

    Directory of Open Access Journals (Sweden)

    A. Hooijer

    2012-02-01

    Full Text Available Peat surface CO2 emission, groundwater table depth and peat temperature were monitored for two years along transects in an Acacia plantation on thick tropical peat (>4 m in Sumatra, Indonesia. A total of 2300 emission measurements were taken at 144 locations, over a 2 year period. The autotrophic root respiration component of CO2 emission was separated from heterotrophic emission caused by peat oxidation in three ways: (i by comparing CO2 emissions within and beyond the tree rooting zone, (ii by comparing CO2 emissions with and without peat trenching (i.e. cutting any roots remaining in the peat beyond the tree rooting zone, and (iii by comparing CO2 emissions before and after Acacia tree harvesting. On average, the contribution of autotrophic respiration to daytime CO2 emission was 21% along transects in mature tree stands. At locations 0.5 m from trees this was up to 80% of the total emissions, but it was negligible at locations more than 1.3 m away. This means that CO2 emission measurements well away from trees were free of any autotrophic respiration contribution and thus represent only heterotrophic emissions. We found daytime mean annual CO2 emission from peat oxidation alone of 94 t ha−1 y−1 at a mean water table depth of 0.8 m, and a minimum emission value of 80 t ha−1 y−1 after correction for the effect of diurnal temperature fluctuations, which may result in a 14.5% reduction of the daytime emission. There is a positive correlation between mean long-term water table depth and peat oxidation CO2 emission. However, no such relation is found for instantaneous emission/water table depth within transects and it is clear that factors other than water table depth also affect peat oxidation and total CO2 emissions. The increase in the temperature of the surface peat due to plantation establishment may explain over 50% of peat oxidation emissions. Our study sets a standard for greenhouse gas flux studies from tropical peatlands under

  2. Immobilized reactor for rapid destruction of recalcitrant organics and inorganics in tannery wastewater

    Institute of Scientific and Technical Information of China (English)

    A. Ganesh Kumar; G. Sekaran; S. Swarnalatha; B. Prasad Rao

    2005-01-01

    The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic activated carbon oxidation(CAACO) reactor, an immobilized cell reactor using chemoautotrophs for the treatment of tannery wastewater. The treatment scheme comprised of anaerobic treatment, sand filtration, and CAACO reactor, which remove COD, BOD, TOC, VFA and sulphides respectively by 86%, 95%, 81%,71% and 100%. Rice bran mesoporous activated carbon prepared indigenously and was used for immobilization of chemoautotrophs. The degradation of xenobiotic compounds by CAACO was confirmed through HPLC and FT-IR techniques.

  3. Uncertainty and sensitivity analysis of control strategies using the benchmark simulation model No1 (BSM1)

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Rodriguez-Roda, Ignasi; Sin, Gürkan;

    2009-01-01

    -NH) controller reduce uncertainty in both overall pollution removal and effluent total Kjeldahl nitrogen. Also, control strategies with an external carbon source reduce the effluent nitrate (S-NO) uncertainty increasing both their economical cost and variability as a trade-off. Finally, the maximum specific...... autotrophic growth rate (mu(A)) causes most of the variance in the effluent for all the evaluated control strategies. The influence of denitrification related parameters, e. g. eta(g) (anoxic growth rate correction factor) and eta(h) (anoxic hydrolysis rate correction factor), becomes less important when a S...

  4. Increase in the biomass of some green algae species in nitrate and ammonium mediums depending on auto-, mixo- or heterotrophic conditions

    Directory of Open Access Journals (Sweden)

    Stefan Gumiński

    2014-02-01

    Full Text Available The increase in total dry mass and protein in cultures of Chlorella pyrenoidosa, Scenedesmus quadricauda and Ankistrodesmus acicularis was studied. Under autotrophic conditions, increases in dry mass were, as a rule, larger in the nitrate medium than in the ammonium one, under mixotrophic conditions the situation was reversed and in the case of heterotrophy, the individual species reacted differently. The dependence ot the protein content increase on the nitrate or ammonium form of the medium was not clear. Changes in time of the pH and rH of the mediums were followed and the interdependence of these changes with the production of biomass is discussed.

  5. Spatial and temporal variability of the phytoplankton community structure in the North Water Polynya, investigated using pigment biomarkers

    DEFF Research Database (Denmark)

    Vidussi, F.; Roy, S.; Lovejoy, C.; Gammelgaard, Marie; Thomsen, Helge Abildhauge; Booth, B.; Tremblay, J.E.; Mostajir, B.

    2004-01-01

    contribution of the different phytoplankton groups to Chl a inferred using a factorization program (CHEMTAX) indicated that the bloom was diatom-dominated (maximum 94% diatoms). The phytoplankton community structure was influenced by the water mass characteristics and the surface circulation pattern....... Autotrophic flagellates dominated in April and May along the Canadian coast, where cold Arctic waters with relatively deep mixed layers were found. In contrast, diatoms dominated in May along the Greenland coast in warmer water masses of Atlantic origin and during June in the whole polynya, except in the...

  6. Denitrification as the dominant nitrogen loss process in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ward, B.B.; Devol, A.H.; Rich, J.J.; Chang, B.X.; Bulow, S.E.; Naik, H.; Pratihary, A.K.; Jayakumar, A.

    of heterotrophic denitrifying bacteria10,11,12. In the absence of oxygen, denitrifiers respire nitrate (NO3 - ) sequentially to nitrite (NO2 - ), nitric and nitrous oxides (NO, N 2 O) and finally to N 2 . In consuming organic matter, they regenerate... and are represented by only 1 or 2 phylotypes 12,13,14 . In contrast to denitrifying bacteria, anammox bacteria are autotrophs that consume NH4 + and NO 2 - in respiration and form biomass by CO 2 fixation. Anammox is thus dependent upon nutrient...

  7. Investigations into the transfer of cesium 137 and strontium 90 in selected exposure pathways

    International Nuclear Information System (INIS)

    This research project investigates the behaviour of radiocesium and strontium 90 in natural conifer forest sites and derives corresponding transfer factors for radioecological calculations. As a point of particular interest the question was investigated in how far the requirements of the different mushroom species and the properties of the forest soil bear on the dynamics and transfer rate of radiocesium and strontium 90. To complement the investigations, autotrophic plants were included. The results of these studies are compared with the behaviour of the same radionuclides on farmland. The differences are discussed. (orig./HP)

  8. Dynamic belowground ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W. F.; Santantonio, D.; McGinty, D.

    1979-01-01

    Roots comprise the primary interface between plant and soil for uptake of water and nutrients. Much is known about the biochemistry, cell physiology and membrane physics associated with these important processes. In this paper we discuss the role of the belowground ecosystem, especially the autotrophic root component, in the structure and function of forest ecosystems. Beyond recognizing roles of anchoring terrestrial plants and uptake of water and nutrients, this component of the forest has been largely neglected in an ecosystem context. In order to focus discussion on the properties of the belowground ecosystem, we use the term rhizosphere to include roots, mycorrhizae, microbes, and rhizophagus invertebrates.

  9. Seagrass community metabolism: assessing the carbon sink capacity of seagrass meadows

    OpenAIRE

    Duarte, Carlos M.; Marbà, Núria; Gacia, Esperança; Fourqurean, James W.; Beggins, Jeff; Barrón, Cristina; Apostolaki, Eugenia T.

    2010-01-01

    The metabolic rates of seagrass communities were synthesized on the basis of a data set on seagrass community metabolism containing 403 individual estimates derived from a total of 155 different sites. Gross primary production (GPP) rates (mean ± SE = 224.9 ± 11.1 mmol O2 m−2 d−1) tended to be significantly higher than the corresponding respiration (R) rates (mean ± SE = 187.6 ± 10.1 mmol O2 m−2 d−1), indicating that seagrass meadows tend to be autotrophic ecosystems, reflected in a positive ...

  10. Soil Carbon Turnover and the Net Ecosystem Carbon Balance of a Northern Hardwood Forest, Michigan, USA

    Science.gov (United States)

    Gough, C. M.; Biswas, S.; Vogel, C. S.; Curtis, P. S.

    2004-12-01

    Soils are a major reservoir of stored carbon (C) in forested ecosystems, containing up to 70% of total ecosystem C. Heterotrophic activity largely dictates the rate of soil C turnover and directly impacts ecosystem C balance. Reliable estimates of net ecosystem productivity (NEP) from ecophysiological and biometric data as well as the refinement of process-based models predicting belowground changes in C storage depend on accurate quantification and partitioning of autotrophic and heterotrophic soil C fluxes. We used field and laboratory measurements of root, microbial and soil respiration in a northern hardwood forest to (1) quantify the annual soil C efflux attributed to heterotrophs and autotrophs from 1999 to 2003; (2) identify the extent to which microclimatic drivers impact interannual variability in microbial activity of the mineral soil and O-horizon; and (3) evaluate the sensitivity of estimated annual NEP to heterotrophic respiration. The study was conducted in an 85-year-old aspen-dominated mixed deciduous forest at the University of Michigan Biological Station Ameriflux site (UMBS ˜Flux) in N. lower Michigan, USA. Soil respiration was monitored from 1999 to 2003. Laboratory incubations of roots, mineral soil and the O-horizon at different temperatures were used to examine the relationship between microclimate and autotrophic and heterotrophic respiration. Empirical models relating root and microbial respiration to temperature were used in combination with soil respiration models and site soil temperature, moisture and root biomass data to estimate the contribution of autotrophic and heterotrophic respiration to total soil C efflux. Heterotrophic soil respiration estimates were combined with other C flux data to calculate annual NEP from 1999 to 2003. Microbially-mediated C turnover was responsible for ˜half of the total annual soil C efflux. Heterotrophic respiration varied by more than 1 Mg C ha-1 yr-1 among years primarily due to interannual

  11. Bioprocess Engineering Aspects of Biopolymer Production by the Cyanobacterium Spirulina Strain LEB 18

    OpenAIRE

    Roberta Guimarães Martins; Igor Severo Gonçalves; Michele Greque de Morais; Jorge Alberto Vieira Costa

    2014-01-01

    Microbial biopolymers can replace environmentally damaging plastics derived from petrochemicals. We investigated biopolymer synthesis by the cyanobacterium Spirulina strain LEB 18. Autotrophic culture used unmodified Zarrouk medium or modified Zarrouk medium in which the NaNO3 content was reduced to 0.25 g L−1 and the NaHCO3 content reduced to 8.4 g L−1 or increased to 25.2 g L−1. Heterotrophic culture used modified Zarrouk medium containing 0.25 g L−1 NaNO3 with the NaHCO3 replaced by 0.2 g ...

  12. 八代海における有害ラフィド藻Chattonella antiquaに対する殺藻及び増殖阻害細菌の時空間的変動

    OpenAIRE

    稲葉, 信晴; 秋里, 綾乃; 黒田, 麻美; 西, 広海; 田原, 義雄; 坂見, 知子; 今井, 一郎

    2016-01-01

    The harmful raphidophyte Cattonella antiqua is known as a notorious red-tide causing autotrophic flagellate. Mass mortalities of mainly cultured yellowtails by C. antiqua in 2009 and 2010 at Yatsushiro Sea, located in Kyushu, the southernmost of the four main islands of Japan, reaching 8.7 billion Japanese yen(about 80 million US dollar) have been newly reported. There is an urgent need to seek strategies for reducing negative impacts by Chattonella red-tides. In this study, temporal and spat...

  13. Spatial variations in time-integrated plankton metabolic rates in Sagami Bay using triple oxygen isotopes and O2:Ar ratios

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Abe, O.; Saino, T.

    community respira- tion (R), which is termed net community production (NCP); the balance between GPP and R (the net metabolic status) dictates whether oceans are net sources or sinks of CO 2 to the atmosphere. Several studies have suggested that metabolic... processes are substantially out of balance in the open-ocean regions, i.e., respiration is higher than produc- tion (del Giorgio and Duarte 2002; Williams et al. 2004), while coastal oceans are net autotrophic (Ducklow and McAllister 2005). Williams (1997...

  14. Microbiology and physiology of anaerobic fermentation of cellulose. Annual report for 1990, 1992, 1993 and final report

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L.G.; Wiegel, J.; Peck, H.D. Jr.; Mortenson, L.E.

    1993-08-31

    This report focuses on the bioconversion of cellulose to methane by various anaerobes. The structure and enzymatic activity of cellulosome and polycellulosome was studied in Clostridium thermocellum. The extracellular enzymes involved in the degradation of plant material and the physiology of fermentation was investigated in anaerobic fungi. Enzymes dealing with CO, CO{sub 2}, H{sub 2}, CH{sub 3}OH, as well as electron transport and energy generation coupled to the acetyl-CoA autotrophic pathway was studied in acetogenic clostridia.

  15. Biogeophysical interactions control the formation of iron oxide microbial biofilms in acidic geothermal outflow channels of Yellowstone National Park

    Science.gov (United States)

    Beam, J.; Berstein, H. C.; Jay, Z.; Kozubal, M. A.; Jennings, R. D.; Inskeep, W. P.

    2012-12-01

    Amorphous iron oxyhydroxide microbial mats in acidic (pH ~ 3) geothermal outflow channels of Yellowstone National Park (YNP) are habitats for diverse populations of autotrophic and heterotrophic microorganisms from the domains Archaea and Bacteria. These systems have been extensively characterized with regards to geochemical, physical, and microbiological (e.g., metagenomics) analyses; however, there is minimal data describing the formation of these iron oxide microbial mats. A conceptual model of Fe(III)-oxide microbial mat development was created, which includes four distinct stages. Autotrophic archaea (Metallosphaera yellowstonensis) and bacteria (Hydrogenobaculum spp.) are the first colonizers (Stage I) that provide pools of organic carbon for heterotrophic thermophiles (Stage II). M. yellowstonensis is an autotrophic Sulfolobales that is responsible for the oxidation of Fe(II) and can thus be defined as the mat 'architect' creating suitable habitats for microbial niches (e.g., anaerobic microorganisms) (Stage III). The last phase of mat formation (Stage IV) represents a pseudo-steady state mature microbial mat, which has been the subject of all previous microbial surveys of these systems. The conceptual model for Fe(III)-oxide microbial mat development was tested by inserting glass (SiO2) microscope slides into the main flow channels of two acidic geothermal springs in YNP. Slides were removed at various time intervals and analyzed for total iron accretion, microbial community structure (i.e., 16S rRNA gene abundance), and mRNA expression of community members. Routine geochemical and physical (e.g., flow) parameters were also measured to decipher their relative contribution to mat development. Initial and previous results show that autotrophic microorganisms (e.g, M. yellowstonensis) are often the first to colonize the glass slides and their activity was confirmed by mRNA expression of genes related to iron oxidation and carbon fixation. Heterotrophs are rare

  16. Microbial ecology studies at two coal mine refuse sites in Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R. M.; Cameron, R. E.

    1978-01-01

    An investigation was made of the microflora associated with coal refuse at two abandoned mines in the midwestern United States. Information was gathered for both the edaphic and the biotic composition of the refuse material. Emphasis was placed on heterotrophic and autotrophic components as to numbers, kinds, and physiological groups. The presence of chemolithotrophs was also investigated. The relationship between abiotic and biotic components in regard to distribution of bacteria, fungi, and algae is discussed. Information presented in this report will be utilized in assessing trends and changes in microbial numbers and composition related to manipulations of the edaphic and biotic ecosystem components associated with reclamation of the refuse piles.

  17. Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites

    DEFF Research Database (Denmark)

    Collalti, A.; Marconi, S.; Ibrom, Andreas;

    2016-01-01

    autotrophic respiration schemes, was implemented in this new daily version. Model ability in reproducing timing and magnitude of daily and monthly GPP fluctuations is validated at intra-annual and inter-annual scale, including extreme anomalous seasons. With the purpose to test the 3D-CMCC FEM applicability...... over Europe without a site-related calibration, the model has been deliberately parametrized with a single set of species-specific parametrizations for each forest ecosystem. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the...

  18. Review:Anaerobic ammonium oxidation for treatment of ammonium-rich wastewaters

    Institute of Scientific and Technical Information of China (English)

    Lei ZHANG; Ping ZHENG; Chongojian TANG; Ren-cun JIN

    2008-01-01

    The concept of anaerobic ammonium oxidation (ANAMMOX) is presently of great interest.The functional bacteria belonging to the Planctomycete phylum and their metabolism are investigated by microbiologists.Meanwhile,the ANAMMOX is equally valuable in treatment of ammonium-rich wastewaters.Related processes including partial nitritation-ANAMMOX and completely autotrophic nitrogen removal over nitrite (CANON) have been developed,and lab-scale experiments proved that both processes were quite feasible in engineering with appropriate control.Successful full-scale practice in the Netherlands will ac-celerate application of the process in future.This review introduces the microbiology and more focuses on application of the ANAMMOX process.

  19. Changing sources of soil respiration with time since fire in a boreal forest

    OpenAIRE

    Czimczik, CI; Trumbore, SE; Carbone, MS; Winston, GC

    2006-01-01

    Radiocarbon signatures (Δ14C) of carbon dioxide (CO2) provide a measure of the age of C being decomposed by microbes or respired by living plants. Over a 2-year period, we measured Δ14C of soil respiration and soil CO2 in boreal forest sites in Canada, which varied primarily in the amount of time since the last stand-replacing fire. Comparing bulk respiration Δ14C with Δ14C of CO2 evolved in incubations of heterotrophic (decomposing organic horizons) and autotrophic (root and moss) components...

  20. [Study of the growth and development of Chlorella on "Kosmos-1887"].

    Science.gov (United States)

    Sychev, V N; Levinskikh, M A; Livanskaia, O G

    1989-01-01

    The growth, development and population characteristics of Chlorella cells flown for 13 days in space were investigated during their postflight cultivation. The growth rate of flown algae did not differ from that of ground-based controls in terms of increases in the cell number and biomass. All basic parameters of the specimens (generation time, number of developing autospores, time ratio of developmental phases) were ontogentically normal. Exposure of the algae to space flight as a component of the algobacterial cenosis--fish autotrophic-heterotrophic system produced no significant effect of the population or individual specimens during their postflight cultivation. PMID:2593605

  1. Modelling and control design for SHARON/Anammox reactor sequence

    DEFF Research Database (Denmark)

    Valverde Perez, Borja; Mauricio Iglesias, Miguel; Sin, Gürkan

    2012-01-01

    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work presents a complete model of the SHARON/Anammox reactor sequence. The dynamics of the reactor were explored pointing out the different scales of the rates in the system: slow microbial...... metabolism against fast chemical reaction and mass transfer. Likewise, the analysis of the dynamics contributed to establish qualitatively the requirements for control of the reactors, both for regulation and for optimal operation. Work in progress on quantitatively analysing different control structure...

  2. Enhanced performance of denitrifying sulfide removal process under micro-aerobic condition

    International Nuclear Information System (INIS)

    The denitrifying sulfide removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide and acetate into di-nitrogen gas, elementary sulfur and carbon dioxide, respectively, at high loading rates. This study determines the reaction rate of sulfide oxidized into sulfur, as well as the reduction of nitrate to nitrite, would be enhanced under a micro-aerobic condition. The presence of limited oxygen mitigated the inhibition effects of sulfide on denitrifier activities, and enhanced the performance of DSR granules. The advantages and disadvantages of applying the micro-aerobic condition to the DSR process are discussed.

  3. Bacterial carbonatogenesis

    International Nuclear Information System (INIS)

    Several series of experiments in the laboratory as well as in natural conditions teach that the production of carbonate particles by heterotrophic bacteria follows different ways. The 'passive' carbonatogenesis is generated by modifications of the medium that lead to the accumulation of carbonate and bicarbonate ions and to the precipitation of solid particles. The 'active' carbonatogenesis is independent of the metabolic pathways. The carbonate particles are produced by ionic exchanges through the cell membrane following still poorly known mechanisms. Carbonatogenesis appears to be the response of heterotrophic bacterial communities to an enrichment of the milieu in organic matter. The active carbonatogenesis seems to start first. It is followed by the passive one which induces the growth of initially produced particles. The yield of heterotrophic bacterial carbonatogenesis and the amounts of solid carbonates production by bacteria are potentially very high as compared to autotrophic or chemical sedimentation from marine, paralic or continental waters. Furthermore, the bacterial processes are environmentally very ubiquitous; they just require organic matter enrichment. Thus, apart from purely evaporite and autotrophic ones, all Ca and/or Mg carbonates must be considered as from heterotrophic bacterial origin. By the way, the carbon of carbonates comes from primary organic matter. Such considerations ask questions about some interpretations from isotopic data on carbonates. Finally, bacterial heterotrophic carbonatogenesis appears as a fundamental phase in the relationships between atmosphere and lithosphere and in the geo-biological evolution of Earth. (author)

  4. Detailing the optimality of photosynthesis in cyanobacteria through systems biology analysis.

    Science.gov (United States)

    Nogales, Juan; Gudmundsson, Steinn; Knight, Eric M; Palsson, Bernhard O; Thiele, Ines

    2012-02-14

    Photosynthesis has recently gained considerable attention for its potential role in the development of renewable energy sources. Optimizing photosynthetic organisms for biomass or biofuel production will therefore require a systems understanding of photosynthetic processes. We reconstructed a high-quality genome-scale metabolic network for Synechocystis sp. PCC6803 that describes key photosynthetic processes in mechanistic detail. We performed an exhaustive in silico analysis of the reconstructed photosynthetic process under different light and inorganic carbon (Ci) conditions as well as under genetic perturbations. Our key results include the following. (i) We identified two main states of the photosynthetic apparatus: a Ci-limited state and a light-limited state. (ii) We discovered nine alternative electron flow pathways that assist the photosynthetic linear electron flow in optimizing the photosynthesis performance. (iii) A high degree of cooperativity between alternative pathways was found to be critical for optimal autotrophic metabolism. Although pathways with high photosynthetic yield exist for optimizing growth under suboptimal light conditions, pathways with low photosynthetic yield guarantee optimal growth under excessive light or Ci limitation. (iv) Photorespiration was found to be essential for the optimal photosynthetic process, clarifying its role in high-light acclimation. Finally, (v) an extremely high photosynthetic robustness drives the optimal autotrophic metabolism at the expense of metabolic versatility and robustness. The results and modeling approach presented here may promote a better understanding of the photosynthetic process. They can also guide bioengineering projects toward optimal biofuel production in photosynthetic organisms. PMID:22308420

  5. The sensitivity of wet and dry tropical forests to climate change in Bolivia

    Science.gov (United States)

    Seiler, C.; Hutjes, R. W. A.; Kruijt, B.; Hickler, T.

    2015-03-01

    Bolivia's forests contribute to the global carbon and water cycle, as well as to global biodiversity. The survival of these forests may be at risk due to climate change. To explore the associated mechanisms and uncertainties, a regionally adapted dynamic vegetation model was implemented for the Bolivian case, and forced with two contrasting climate change projections. Changes in carbon stocks and fluxes were evaluated, factoring out the individual contributions of atmospheric carbon dioxide ([CO2]), temperature, and precipitation. Impacts ranged from a strong increase to a severe loss of vegetation carbon (cv), depending on differences in climate projections, as well as the physiological response to rising [CO2]. The loss of cv simulated for an extremely dry projection was primarily driven by a reduction in gross primary productivity, and secondarily by enhanced emissions from fires and autotrophic respiration. In the wet forest, less precipitation and higher temperatures equally reduced cv, while in the dry forest, the impact of precipitation was dominating. The temperature-related reduction of cv was mainly due to a decrease in photosynthesis and only to lesser extent because of more autotrophic respiration and less stomatal conductance as a response to an increasing atmospheric evaporative demand. Under an extremely dry projection, tropical dry forests were simulated to virtually disappear, regardless of the potential fertilizing effect of rising [CO2]. This suggests a higher risk for forest loss along the drier southern fringe of the Amazon if annual precipitation will decrease substantially.

  6. Assessing the ecological status of plankton in Anjos Bay: a flow cytometry approach

    Directory of Open Access Journals (Sweden)

    G. C. Pereira

    2010-08-01

    Full Text Available This aim of this paper is to assess the use of the heterotrophic/autotrophic ratio as an early indicator of trophic status as a part of development of a real time monitoring program at Anjos Bay, Rio de Janeiro, Brazil. An in-situ flow cytometer was used to quantify the abundances of phytoplankton and cyanobacteria, which were identified by chlorophyll and phycoerythrin autofluorescence, respectively. Heterotrophic prokaryotes and viruses were quantified by DNA-binding fluorochromes; merozooplankton larvae were collected by plankton net and quantified by stereomicroscopy. The temporal and spatial distributions of these variables were evaluated on the basis of weekly observations from August 2006 to September 2007. The heterotrophic/autotrophic ratio and the viral abundance were correlated with upwelling events and assume an apparently seasonal pattern. A possible control mechanism and influential factors are discussed, and it is concluded that this ecosystem is bottom-up controlled under eutrophic conditions and top-down controlled under oligotrophic conditions.

  7. The geomicrobiology of calcium montmorillonite (Fuller's Earth)

    International Nuclear Information System (INIS)

    Oxfordshire Fuller's Earth contains high populations of aerobic heterotrophic microorganisms and smaller populations of anaerobic heterotrophs. These groups seem to be generally unaffected by depth. The aerobic heterotroph activity in Fuller's Earth extract is continuous indicating that the necessary organic carbon is available. Chemical analysis has shown that all other necessary nutrients are present in the waters sampled. Activity can also be stimulated by the addition of TCA cycle intermediates. It is likely that the carbon dioxide produced by the aerobic heterotrophs could be utilised by autotrophic populations. Similarly, bicarbonate rich groundwaters could also supply inorganic carbon for them. These populations already exist at low levels and include corrosion important microorganisms. The organic carbon thus produced by the autotrophs could be used as a source for further heterotrophic activity. These findings indicate that microbial inhibition would only occur if the availability of organic carbon was controlled. The use of Fuller's Earth as a backfill material in other groundwater environments, especially those rich in bicarbonate, may stimulate various microbial groups and lead to interactions affecting waste isolation. It would thus be prudent to reduce or eliminate the organic carbon content in Fuller's Earth should it be used as a backfill material. (author)

  8. Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process

    International Nuclear Information System (INIS)

    Highlights: • Simultaneous heterotrophic and autotrophic denitrification was stimulated. • Simultaneous bioreduction of nitrate and chromate was achieved. • Total chromium decreased 3−–N and Cr(VI) concentrations of 75 mg/L and 10 mg/L, respectively, and 3.7 h HRT. Maximum denitrification rate was 0.5 g NO3−–N/(L.d) when the bioreactor was fed with 75 mg/L NO3−–N, 150 mg/L methanol and 10 mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 μg/L provided that influent Cr(VI) concentration was equal or below 5 mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed

  9. Sulfur-based mixotrophic denitrification corresponding to different electron donors and microbial profiling in anoxic fluidized-bed membrane bioreactors.

    Science.gov (United States)

    Zhang, Lili; Zhang, Chao; Hu, Chengzhi; Liu, Huijuan; Bai, Yaohui; Qu, Jiuhui

    2015-11-15

    Sulfur-based mixotrophic denitrifying anoxic fluidized bed membrane bioreactors (AnFB-MBR) were developed for the treatment of nitrate-contaminated groundwater with minimized sulfate production. The nitrate removal rates obtained in the methanol- and ethanol-fed mixotrophic denitrifying AnFB-MBRs reached 1.44-3.84 g NO3 -N/L reactor d at a hydraulic retention time of 0.5 h, which were significantly superior to those reported in packed bed reactors. Compared to methanol, ethanol was found to be a more effective external carbon source for sulfur-based mixotrophic denitrification due to lower sulfate and total organic carbon concentrations in the effluent. Using pyrosequencing, the phylotypes of primary microbial groups in the reactor, including sulfur-oxidizing autotrophic denitrifiers, methanol- or ethanol-supported heterotrophic denitrifiers, were investigated in response to changes in electron donors. Principal component and heatmap analyses indicated that selection of electron donating substrates largely determined the microbial community structure. The abundance of Thiobacillus decreased from 45.1% in the sulfur-oxidizing autotrophic denitrifying reactor to 12.0% and 14.2% in sulfur-based methanol- and ethanol-fed mixotrophic denitrifying bioreactors, respectively. Heterotrophic Methyloversatilis and Thauera bacteria became more dominant in the mixotrophic denitrifying bioreactors, which were possibly responsible for the observed methanol- and ethanol-associated denitrification. PMID:26364226

  10. Autohydrogenotrophic denitrification by a bioelectrochemical process: A viability study

    Directory of Open Access Journals (Sweden)

    Mahdi Safari

    2014-06-01

    Full Text Available ABSTRACT In this study, viability of the autotrophic bacteria was investigated in a denitrification process. Bench-scale bioelectrochemical denitrification with separated chambers reactor were applied for nitrate reduction from synthetic wastewater. The influences of current density, retention time, mixing on viability of autotrophic denitrifying bacteria were investigated in the bioelectrochemical reactor (BER. It was found that by increasing the current density up to 8 mA/cm2, nitrate reduction rate was increased. At higher current density (24 - 32 mA/cm2, denitrification rate due to excess of hydrogen gas on cathode surface and accumulation of nitrite, was decreased. Low current density (<16 mA/cm2 has not had a significant effect on viability of denitrifying bacteria. Mixing of the solution reduced the adverse effects of electric current on bacteria and enhanced the denitrification rate which was mainly due to prevention of bacteria localization, increasing the contact of hydrogen and bacteria, and delay in membrane fouling. The viability of cultivable bacteria has not been significantly influenced by running time.

  11. Psychrophilic Biomass Producers in the Trophic Chain of the Microbial Community of Lake Untersee, Antarctica

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.

    2010-01-01

    The study of photosynthetic microorganisms from the Lake Untersee samples showed dispersed distribution of phototrophs within 80 m water column. Lake Untersee represents a unique ecosystem that experienced complete isolation: sealed by the Anuchin Glacier for many millennia. Consequently, its biocenosis has evolved over a significant period of time without exchange or external interaction with species from other environments. The major producers of organic matter in Lake Untersee are represented by phototrophic and chemolithotrophic microorganisms. This is the traditional trophic scheme for lacustrine ecosystems on Earth. Among the phototrophs, diatoms were not found, which differentiates this lake from other known ecosystems. The dominant species among phototrophs was Chlamydomonas sp. with typical morphostructure: green chloroplasts, bright red round spot, and two polar flagella near the opening. As expected, the physiology of studied phototrophs was limited by low temperature, which defined them as obligate psychrophilic microorganisms. By the quantity estimation of methanogenesis in this lake, the litho-autotrophic production of organic matter is competitive with phototrophic production. However, pure cultures of methanogens have not yet been obtained. We discuss the primary producers of organic matter and the participation of our novel psychrophilic homoacetogen into the litho-autotrophic link of biomass production in Lake Untersee.

  12. Two-step nitrification in a pure moving bed biofilm reactor-membrane bioreactor for wastewater treatment: nitrifying and denitrifying microbial populations and kinetic modeling.

    Science.gov (United States)

    Leyva-Díaz, J C; González-Martínez, A; Muñío, M M; Poyatos, J M

    2015-12-01

    The moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) is a novel solution to conventional activated sludge processes and membrane bioreactors. In this study, a pure MBBR-MBR was studied. The pure MBBR-MBR mainly had attached biomass. The bioreactor operated with a hydraulic retention time (HRT) of 9.5 h. The kinetic parameters for heterotrophic and autotrophic biomasses, mainly nitrite-oxidizing bacteria (NOB), were evaluated. The analysis of the bacterial community structure of the ammonium-oxidizing bacteria (AOB), NOB, and denitrifying bacteria (DeNB) from the pure MBBR-MBR was carried out by means of pyrosequencing to detect and quantify the contribution of the nitrifying and denitrifying bacteria in the total bacterial community. The relative abundance of AOB, NOB, and DeNB were 5, 1, and 3%, respectively, in the mixed liquor suspended solids (MLSS), and these percentages were 18, 5, and 2%, respectively, in the biofilm density (BD) attached to carriers. The pure MBBR-MBR had a high efficiency of total nitrogen (TN) removal of 71.81±16.04%, which could reside in the different bacterial assemblages in the fixed biofilm on the carriers. In this regard, the kinetic parameters for autotrophic biomass had values of YA=2.3465 mg O2 mg N(-1), μm, A=0.7169 h(-1), and KNH=2.0748 mg NL(-1). PMID:26264139

  13. Role of the arbuscular mycorrhizal symbiosis in tolerance response against Armillaria mellea in lavender

    Directory of Open Access Journals (Sweden)

    Cinta Calvet

    2015-09-01

    Full Text Available Lavender species form the arbuscular mycorrhizal symbiosis and are at the same time highly susceptible to white root rot. In an attempt to evaluate the response of mycorrhizal Lavandula angustifolia L. to Armillaria mellea (Vahl:Fr P. Kumm in a greenhouse experiment, plants were previously inoculated with an isolate of the arbuscular mycorrhizal fungus Rhizophagus irregularis (former Glomus intraradices BEG 72 and the influence of the pH growing medium on the plant-symbiont-pathogen interaction was tested in gnotobiotic autotrophic growth systems in which mycorrhizal inoculum was obtained from root organ cultures. After ten months growth dual-inoculated lavender plants grown in containers with a pasteurized substrate mixture produced a similar number of spikes than healthy plants and achieved equivalent plant diameter coverage. When the growing medium in the autotrophic systems was supplemented with calcium carbonate, the inoculation of lavender plantlets with R. irregularis at higher pH (7.0 and 8.5 media caused a significant decrease of A. mellea presence in plant roots, as detected by qPCR. Moreover, the observation of internal root mycorrhizal infection showed that the extent of mycorrhizal colonization increasedin plant rootsgrown at higher pH, indicating that tolerance to white root rot in lavender plants inoculated with R. irregularis could be associated to mycorrhizal establishment.

  14. The geomicrobiology of used and disused mines in Britain

    International Nuclear Information System (INIS)

    Several used and disused mines in Britain have been analysed for microbial presence, content and activity. The sites sampled are located in Cornwall, Derbyshire and Cumbria. The mines in Cornwall can be called 'working' and were being operated at the time of sampling. The mine in Derbyshire was disused until recently re-opened by cavers while the mines in Cumbria had remained closed up to the time of sampling. Waters and solid materials have been sampled where detailed microbiology has been undertaken. In Cumbria a detailed description of structures of biological interest was carried out. Both heterotrophic and autotrophic microorganisms have been found in some waters and on mine walls. The actual content of each mine is different according to local conditions and chemistries. The results of the microbiological analyses are given. The origin of these microorganisms cannot be determined although it is likely that they have been introduced by water running down mine shafts from surface strata and/or from excavation processes. Activity measurements have shown that waters in some mines are organic carbon limited. There are indications from the working mines that such carbon would be available from autotrophic populations present within the ecosystem or from backfill material. (author)

  15. Significance of different microalgal species for growth of moon jellyfish ephyrae, Aurelia sp.1

    Science.gov (United States)

    Zheng, Shan; Sun, Xiaoxia; Wang, Yantao; Sun, Song

    2015-10-01

    The scyphozoan Aurelia aurita (Linnaeus) sp. l., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. The effects of different microalgal species on the growth of newly-released Aurelia sp.1 ephyrae were studied under laboratory conditions. We fed ephyrae with four different microalgal species (diatom, autotrophic dinoflagellate, heterotrophic dinoflagellate, and chlorophyta) plus Artemia nauplii for 12-24 d at 18°C. Results showed that the growth rate diverged significantly for Artemia nauplii compared to other food types. In addition, there was no significant variation between the growth rates for Skeletonema costatum and Prorocentrum donghaiense, and no significant variation was found in the growth rates for N. scintillans and P. subcordiformis. Artemia nauplii could support the energy requirement for the newly-released ephyrae to develop to meduase, and the ephyrae with Artemia nauplii showed a significant average growth rate of 25.85% d-1. Newly-released ephyrae could grow slightly with some species of microalgae in the earliest development stage. Chain diatom Skeletonema costatum and autotrophic dinoflagellate Prorocentrum donghaiense, could not support the growth of the ephyrae, while heterotrophic dinoflagellate Noctiluca scintillans and chlorophyta Platymonas subcordiformis could support the growth of the ephyrae. However, none of the ephyrae fed with the tested phytoplankton could mature to medusae.

  16. Investigation of the microbial diversity of an extremely acidic, metal-rich water body (Lake Robule, Bor, Serbia

    Directory of Open Access Journals (Sweden)

    Stanković Srđan

    2014-01-01

    Full Text Available An investigation of the microbial diversity of the extremely acidic, metal-rich Lake Robule was carried out using culture-dependant and culture-independent (T-RFLP methods, and the ability of indigenous bacteria from the lake water to leach copper from a mineral concentrate was tested. T-RFLP analysis revealed that the dominant bacteria in lake water samples were the obligate heterotroph Acidiphilium cryptum (~50% of total bacteria and the iron-oxidizing autotroph Leptospirillum ferrooxidans (~40% The iron/sulfur-oxidizing autotroph Acidithiobacillus ferrooxidans had been reported to be the most abundant bacteria in the lake in an earlier study by other authors, but it was not detected in the present study using T-RFLP. Although it was isolated on solid media and detected in enrichment (bioleaching cultures. The presence of the two bacterial species detected by T-RFLP (L. ferrooxidans and A. cryptum was also confirmed by cultivation on solid media. The presence and relative abundance of bacteria inhabiting Lake Robule was explained by the physiological characteristics of the bacteria and the physico-chemical characteristics of the lake water. [Projekat Ministarstva nauke Republike Srbije, br. 176016 i br.173048

  17. The Genome of the Epsilonproteobacterial Chemolithoautotroph Sulfurimonas dentrificans

    Energy Technology Data Exchange (ETDEWEB)

    USF Genomics Class; Sievert, Stefan M.; Scott, Kathleen M.; Klotz, Martin G.; Chain, Patrick S.G.; Hauser, Loren J.; Hemp, James; Hugler, Michael; Land, Miriam; Lapidus, Alla; Larimer, Frank W.; Lucas, Susan; Malfatti, Stephanie A.; Meyer, Folker; Paulsen, Ian T.; Ren, Qinghu; Simon, Jorg

    2007-08-08

    Sulfur-oxidizing epsilonproteobacteria are common in a variety of sulfidogenic environments. These autotrophic and mixotrophic sulfur-oxidizing bacteria are believed to contribute substantially to the oxidative portion of the global sulfur cycle. In order to better understand the ecology and roles of sulfur-oxidizing epsilonproteobacteria, in particular those of the widespread genus Sulfurimonas, in biogeochemical cycles, the genome of Sulfurimonas denitrificans DSM1251 was sequenced. This genome has many features, including a larger size (2.2 Mbp), that suggest a greater degree of metabolic versatility or responsiveness to the environment than seen for most of the other sequenced epsilonproteobacteria. A branched electron transport chain is apparent, with genes encoding complexes for the oxidation of hydrogen, reduced sulfur compounds, and formate and the reduction of nitrate and oxygen. Genes are present for a complete, autotrophic reductive citric acid cycle. Many genes are present that could facilitate growth in the spatially and temporally heterogeneous sediment habitat from where Sulfurimonas denitrificans was originally isolated. Many resistance-nodulation-development family transporter genes (10 total) are present; of these, several are predicted to encode heavy metal efflux transporters. An elaborate arsenal of sensory and regulatory protein-encoding genes is in place, as are genes necessary to prevent and respond to oxidative stress.

  18. Investigation of the Prebiotic Synthesis of Amino Acids and RNA Bases from CO2 using FeS/H2S as a Reducing Agent

    Science.gov (United States)

    Keefe, Anthony D.; Miller, Stanley L.; McDonald, Gene; Bada, Jeffrey

    1995-01-01

    An autotrophic theory of the origin of metabolism and life has been proposed in which carbon dioxide is reduced by ferrous sulfide and hydrogen sulfide by means of a reversed citric acid cycle, leading to the production of amino acids. Similar processes have been proposed for purine synthesis. Ferrous sulfide is a strong reducing agent in the presence of hydrogen sulfide and can produce hydrogen as well as reduce alkenes, alkynes, and thiols to saturated hydrocarbons and reduce ketones to thiols. However, the reduction of carbon dioxide has not been demonstrated. We show here that no amino acids, purines, or pyrimidines are produced from carbon dioxide with the ferrous sulfide and hydrogen sulfide system. Furthermore, this system does not produce amino acids from carboxylic acids by reductive amination and carboxylation. Thus, the proposed autotrophic theory, using carbon dioxide, ferrous sulfide, and hydrogen sulfide, lacks the robustness needed to be a geological process and is, therefore, unlikely to have played a role in the origin of metabolism or the origin of life.

  19. Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

    Directory of Open Access Journals (Sweden)

    Adarme-Vega T

    2012-07-01

    Full Text Available Abstract Omega-3 fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5 and DHA (C22:6 and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.

  20. Distribution and hydrophobic properties of Extracellular Polymeric Substances in biofilms in relation towards cohesion.

    Science.gov (United States)

    Ras, M; Lefebvre, D; Derlon, N; Hamelin, J; Bernet, N; Paul, E; Girbal-Neuhauser, E

    2013-05-20

    A heterotrophic biofilm (B1) and a mixed autotrophic-heterotrophic biofilm (B2) were developed in an annular reactor and submitted to an erosion test in order to selectively detach top layers from the bottom layers. Densities of the basal layers were 5-fold higher and 3-fold higher than the densities of the entire biofilms B1 and B2, respectively. After extraction, EPS content in B1 biofilm was found higher in the basal layer (95 mg g⁻¹ VSS) compared to the top layer (30 mg g⁻¹ VSS), while B2 biofilm had a higher EPS content in the top layer (303 mg g⁻¹ VSS) compared to the basal layer (135 mg g⁻¹ VSS). Hydrophobic Interaction Chromatography (HIC) indicates that hydrophobic EPS (HEPS) in both biofilms reached 21% of EPS in basal cohesive layers, and remained slightly lower or identical (16-19%) in top detached biofilm layers. Strong interacting HEPS were found in a higher proportion in the mixed autotrophic-heterotrophic B2 which was also more diversified in terms of bacterial populations than the B1 heterotrophic biofilm. These results show that HEPS content correlates better with cohesive properties of the biofilm layers than global EPS content and that strong hydrophobic adhesion forces may be related to microbial populations such as the presence of nitrifiers. PMID:23524058

  1. Optimization of water balance within the martian crew life support system

    Science.gov (United States)

    Sychev, V.; Levinskikh, M.

    The present-day scenarios of the first exploration mission differ in the total length crew size period of the stay on Mars etc However no matter the scenario one of the common problems is optimization of water balance within the crew life support system Water balance optimization implies in addition to regeneration of atmospheric moisture and urine also dehydration of biowastes In this mission all wastes will be stored and for this reason safe storage is prerequisite Investigations of two-component laboratory BLSS in which the autotrophic component was composed of algae Spirulina platensis and the heterotrophic component was represented by Japanese quail Coturnix coturnix japonica dom showed that optimization of the autotrophic and heterotrophic gas exchange and water regeneration from quail biowastes could raise the system susbstance balance to 76 of the total balance during autonomic cultivation of algae and birds In these investigations dehydration of quail biowastes caused significant pollution of water and air by organics toxic for humans It was demonstrated that the sorption technologies applied on the Russian space station MIR and ISS cannot fully absorb organic contaminants released in the process of quail wastes drying Algal suspension as a hydrobiological filter was able to control the organic pollination of both air and water These results are in agreement with the data of ground-based simulation studies with participation of human subjects at IBMP According to the simulation data intensive

  2. Evaluation of Cyanothece sp. ATCC 51142 as a candidate for inclusion in a CELSS

    Science.gov (United States)

    Schneegurt, M. A.; Arieli, B.; Nielsen, S. S.; Trumbo, P. R.; Sherman, L. A.; Mitchell, C. A. (Principal Investigator)

    1996-01-01

    Controlled ecological life support systems (CELSS) have been proposed to make long-duration manned space flights more cost-effective. Higher plants will presumably provide food and a breathable atmosphere for the crew. It has been suggested that imbalances between the CO2/O2 gas exchange ratios of the heterotrophic and autotrophic components of the system will inevitably lead to an unstable system, and the loss of O2 from the atmosphere. Ratio imbalances may be corrected by including a second autotroph with an appropriate CO2/O2 gas exchange ratio. Cyanothece sp. ATCC 51142 is a large unicellular N2-fixing cyanobacterium, exhibiting high growth rates under diverse physiological conditions. A rat-feeding study showed the biomass to be edible. Furthermore, it may have a CO2/O2 gas exchange ratio that theoretically can compensate for ratio imbalances. It is suggested that Cyanothece spp. could fulfill several roles in a CELSS: supplementing atmosphere recycling, generating fixed N from the air, providing a balanced protein supplement, and protecting a CELSS in case of catastrophic crop failure.

  3. [Application and obstacles of ANAMMOX process].

    Science.gov (United States)

    Jin Rencun; Zhang, Zhengzhe; Ji, Yuxin; Chen, Hui; Guo, Qiong; Zhou, Yuhuang; Wu, Conghui; Jin, Rencun

    2014-12-01

    Anaerobic ammonium oxidation (ANAMMOX), as its essential advantages of high efficiency and low cost, is a promising novel biological nitrogen elimination process with attractive application prospects. Over the past two decades, many processes based on the ANAMMOX reaction have been continuously studied and applied to practical engineering, with the perspective of reaching 100 full-scale installations in operation worldwide by 2014. Our review summarizes various forms of ANAMMOX processes, including partial nitritation-ANAMMOX, completely autotrophic nitrogen removal over nitrite, oxygen limited autotrophic nitrification and denitrification, denitrifying ammonium oxidation, aerobic deammonification, simultaneous partial nitrification, ANAMMOX and denitrification, single-stage nitrogen removal using ANAMMOX and partial nitritation. We also compare the operating conditions for one-stage and two-stage processes and summarize the obstacles and countermeasures in engineering application of ANAMMOX systems, such as moving bed biofilm reactor, sequencing batch reactor and granular sludge reactor. Finally, we discuss the future research and application direction, which should focus on the optimization of operating conditions and applicability of the process to the actual wastewater, especially on automated control and the impact of special wastewater composition on process performance. PMID:26016370

  4. How switches and lags in biophysical regulators affect spatial-temporal variation of soil respiration in an oak-grass savanna

    Science.gov (United States)

    Baldocchi, Dennis; Tang, Jianwu; Xu, Liukang

    2006-06-01

    Complex behavior, associated with soil respiration of an oak-grass savanna ecosystem in California, was quantified with continuous measurements of CO2 exchange at two scales (soil and canopy) and with three methods (overstory and understory eddy covariance systems, soil respiration chambers, and a below-ground CO2 flux gradient system). To partition soil respiration into its autotrophic and heterotrophic components, we exploited spatial gradients in the landscape and seasonal variations in rainfall. During the dry summer, heterotrophic respiration was dominant in the senesced grassland area, whereas autotrophic respiration by roots and the feeding of microbes by root exudates was dominant under the trees. A temporal switch in soil respiration occurred in the spring. But the stimulation of root respiration lagged the timing of leaf-out by the trees. Another temporal switch in soil respiration occurred at the start of autumn rains. This switch was induced by the rapid germination of grass seed and new grass growth. Isolated summer rain storms caused a pulse in soil respiration. Such rain events stimulated microbial respiration only; the rain was not sufficient to replenish soil moisture in the root zone or to germinate grass seed. Soil respiration lagged photosynthetic activity on hourly scales. The likely mechanism is the slow translocation of photosynthate to the roots and associated microbes. Another lag occurred on daily scales because of modulations in photosynthesis and stomatal conductance by the passage of dry and humid air masses.

  5. Stable isotope signatures confirm carbon and nitrogen gain through ectomycorrhizas in the ghost orchid Epipogium aphyllum Swartz.

    Science.gov (United States)

    Liebel, H T; Gebauer, G

    2011-03-01

    Epipogium aphyllum is a rare Eurasian achlorophyllous forest orchid known to associate with fungi that form ectomycorrhizas, while closely related orchids of warm humid climates depend on wood- or litter-decomposer fungi. We conducted (13) C and (15) N stable isotope natural abundance analyses to identify the organic nutrient source of E. aphyllum from Central Norway. These data for orchid shoot tissues, in comparison to accompanying autotrophic plants, document C and N flow from ectomycorrhizal fungi to the orchid. DNA data from fungal pelotons in the orchid root cortex confirm the presence of Inocybe and Hebeloma, which are both fungi that form ectomycorrhizas. The enrichment factors for (13) C and (15) N of E. aphyllum are used to calculate a new overall average enrichment factor for mycoheterotrophic plants living in association with ectomycorrhizal fungi (ε(13) C ± 1 SD of 7.2 ± 1.6 ‰ and ε(15) N ± 1 SD of 12.8 ± 3.9 ‰). These can be used to estimate the fungal contribution to organic nutrient uptake by partially mycoheterotrophic plants where fully mycoheterotrophic plants are lacking. N concentrations in orchid tissue were unusually high and significantly higher than in accompanying autotrophic leaf samples. This may be caused by N gain of E. aphyllum from obligate ectomycorrhizal fungi. We show that E. aphyllum is an epiparasitic mycoheterotrophic orchid that depends on ectomycorrhizal Inocybe and Hebeloma to obtain C and N through a tripartite system linking mycoheterotrophic plants through fungi with forest trees. PMID:21309973

  6. Hydrogen consumption by methanogens on the early Earth

    Science.gov (United States)

    Kral, T. A.; Brink, K. M.; Miller, S. L.; McKay, C. P.; Bada, J. L. (Principal Investigator)

    1998-01-01

    It is possible that the first autotroph used chemical energy rather than light. This could have been the main source of primary production after the initial inventory of abiotic organic material had been depleted. The electron acceptor most readily available for use by this first chemoautotroph would have been CO2. The most abundant electron donor may have been H2 that would have been outgassing from volcanoes at a rate estimated to be as large as 10(12) moles yr-1, as well as from photo-oxidation of Fe+2. We report here that certain methanogens will consume H2 down to partial pressures as low as 4 Pa (4 x 10(-5) atm) with CO2 as the sole carbon source at a rate of 0.7 ng H2 min-1 microgram-1 cell protein. The lower limit of pH2 for growth of methanogens can be understood on the basis that the pH2 needs to be high enough for one ATP to be synthesized per CO2 reduced. The pH2 values needed for growth measured here are consistent with those measured by Stevens and McKinley for growth of methanogens in deep basalt aquifers. H2-consuming autotrophs are likely to have had a profound effect on the chemistry of the early atmosphere and to have been a dominant sink for H2 on the early Earth after life began rather than escape from the Earth's atmosphere to space.

  7. Coupled RNA-SIP and metatranscriptomics of active chemolithoautotrophic communities at a deep-sea hydrothermal vent.

    Science.gov (United States)

    Fortunato, Caroline S; Huber, Julie A

    2016-08-01

    The chemolithoautotrophic microbial community of the rocky subseafloor potentially provides a large amount of organic carbon to the deep ocean, yet our understanding of the activity and metabolic complexity of subseafloor organisms remains poorly described. A combination of metagenomic, metatranscriptomic, and RNA stable isotope probing (RNA-SIP) analyses were used to identify the metabolic potential, expression patterns, and active autotrophic bacteria and archaea and their pathways present in low-temperature hydrothermal fluids from Axial Seamount, an active submarine volcano. Metagenomic and metatranscriptomic results showed the presence of genes and transcripts for sulfur, hydrogen, and ammonium oxidation, oxygen respiration, denitrification, and methanogenesis, as well as multiple carbon fixation pathways. In RNA-SIP experiments across a range of temperatures under reducing conditions, the enriched (13)C fractions showed differences in taxonomic and functional diversity. At 30 °C and 55 °C, Epsilonproteobacteria were dominant, oxidizing hydrogen and primarily reducing nitrate. Methanogenic archaea were also present at 55 °C, and were the only autotrophs present at 80 °C. Correspondingly, the predominant CO2 fixation pathways changed from the reductive tricarboxylic acid (rTCA) cycle to the reductive acetyl-CoA pathway with increasing temperature. By coupling RNA-SIP with meta-omics, this study demonstrates the presence and activity of distinct chemolithoautotrophic communities across a thermal gradient of a deep-sea hydrothermal vent. PMID:26872039

  8. The deep-sea glass sponge Lophophysema eversa harbours potential symbionts responsible for the nutrient conversions of carbon, nitrogen and sulfur.

    Science.gov (United States)

    Tian, Ren-Mao; Sun, Jin; Cai, Lin; Zhang, Wei-Peng; Zhou, Guo-Wei; Qiu, Jian-Wen; Qian, Pei-Yuan

    2016-09-01

    Glass sponge (Hexactinellida, Porifera) is a special lineage because of its unique tissue organization and skeleton material. Structure and physiology of glass sponge have been extensively studied. However, our knowledge of the glass sponge-associated microbial community and of the interaction with the host is rather limited. Here, we performed genomic studies on the microbial community in the glass sponge Lophophysema eversa in seamount. The microbial community was dominated by an ammonia-oxidizing archaeum (AOA), a nitrite-oxidizing bacterium (NOB) and a sulfur-oxidizing bacterium (SOB), all of which were autotrophs. Genomic analysis on the AOA, NOB and SOB in the sponge revealed specific functional features of sponge-associated microorganisms in comparison with the closely related free-living relatives, including chemotaxis, phage defence, vitamin biosynthesis and nutrient uptake among others, which are related to ecological functions. The three autotrophs play essential roles in the cycles of carbon, nitrogen and sulfur in the microenvironment inside the sponge body, and they are considered to play symbiotic roles in the host as scavengers of toxic ammonia, nitrite and sulfide. Our study extends knowledge regarding the metabolism and the evolution of chemolithotrophs inside the invertebrate body. PMID:26637128

  9. Filamentous cyanobacteria fossils and their significance in the Permian-Triassic boundary section at Laolongdong, Chongqing

    Institute of Scientific and Technical Information of China (English)

    JIANG HongXia; WU YaSheng; CAI ChunFang

    2008-01-01

    The microbial communities blooming immediately after the end-Permian mass extinction represent abnormally extreme environments, and vary in different areas. In this study, filamentous cyanobacterial biota was found in the strata after the extinction in the famous Permian-Triassic boundary section at Laolongdong, Chongqing, southwest China. In thin sections, the filamentous cyanobacterial fossils are below 1 mm in length, and generally taper to one end, with the widest diameter up to 0.08 mm. Some of them are curved, indicating that they are soft in life. Their walls are composed of cryptocrystalline to microcrystalline calcites. The filaments have round cross section, and are internally filled with micrites and fine sparry calcites, which indicate that the filaments are originally empty. They are randomly dis-tributed in the rocks, but in some places, they tend to be distributed in radial pattern. The filamentous organisms are morphologically similar to Rivularia of Rivulariaceae, Cyanobacteria Phylum, but with calcified sheaths, and are tentatively regarded as an indeterminate new species in Rivularia: Rivularia sp. Cyanobacteria are photosynthetic autotrophic, and can survive in dysoxic condition. The blooming of this organism and the absence of other organisms may indicate that the environment was oxygen-deficient and shallow, since this photosynthetic autotrophic organism needed to live within photic zone.

  10. Microbial diversity associated with four functional groups of benthic reef algae and the reef-building coral Montastraea annularis.

    Science.gov (United States)

    Barott, Katie L; Rodriguez-Brito, Beltran; Janouškovec, Jan; Marhaver, Kristen L; Smith, Jennifer E; Keeling, Patrick; Rohwer, Forest L

    2011-05-01

    The coral reef benthos is primarily colonized by corals and algae, which are often in direct competition with one another for space. Numerous studies have shown that coral-associated Bacteria are different from the surrounding seawater and are at least partially species specific (i.e. the same bacterial species on the same coral species). Here we extend these microbial studies to four of the major ecological functional groups of algae found on coral reefs: upright and encrusting calcifying algae, fleshy algae, and turf algae, and compare the results to the communities found on the reef-building coral Montastraea annularis. It was found using 16S rDNA tag pyrosequencing that the different algal genera harbour characteristic bacterial communities, and these communities were generally more diverse than those found on corals. While the majority of coral-associated Bacteria were related to known heterotrophs, primarily consuming carbon-rich coral mucus, algal-associated communities harboured a high percentage of autotrophs. The majority of algal-associated autotrophic Bacteria were Cyanobacteria and may be important for nitrogen cycling on the algae. There was also a rich diversity of photosynthetic eukaryotes associated with the algae, including protists, diatoms, and other groups of microalgae. Together, these observations support the hypothesis that coral reefs are a vast landscape of distinctive microbial communities and extend the holobiont concept to benthic algae. PMID:21272183

  11. A Review on the Assessment of Stress Conditions for Simultaneous Production of Microalgal Lipids and Carotenoids.

    Science.gov (United States)

    Minhas, Amritpreet K; Hodgson, Peter; Barrow, Colin J; Adholeya, Alok

    2016-01-01

    Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids) under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C) such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME), and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions. PMID:27199903

  12. Stable isotopic study of effects of N deposition on ammonium cycling in a boreal forest in Northern China

    Science.gov (United States)

    Li, Sheng-Gong; Gao, Wen-Long; Kou, Liang; Zhang, Jin-Bo; Müller, Christoph

    2016-04-01

    There is still lacking of study on the effect of N deposition on microbial N cycling in boreal forests. Here we present results from a N deposition stimulation experiment to show that relatively low rate of N deposition (40 kg NH4Cl-N hm‑2 a‑1) caused a decoupling of ammonium cycling in mineral soil of a boreal coniferous forest in the Great Xing' an Mountain region of China. The uncoupled microbial NH4+ cycling is likely due to reduced NH4+ immobilization possibly as a result of a change in soil N status. Soil autotrophic nitrification rates decreased as NH4+ immobilization decreased. However, the abundance of ammonia-oxidizing archaea (AOA) also presented a decreasing trend as NH4+ immobilization decreased, which explains the reduction in autotrophic nitrification. In addition, gross NO3- production and NO3- retention processes (NO3- immobilization, and dissimilatory nitrate reduction to ammonium DNRA) in the soil did not change with enhanced N deposition. These results demonstrate that soil microbial NH4+ consumption processes are more prone to be affected by enhanced N deposition.

  13. A steady-state biofilm model for simultaneous reduction of nitrate and perchlorate, part 1: model development and numerical solution.

    Science.gov (United States)

    Tang, Youneng; Zhao, Heping; Marcus, Andrew K; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

    2012-02-01

    A multispecies biofilm model is developed for simultaneous reduction of nitrate and perchlorate in the H(2)-based membrane biofilm reactor. The one-dimension model includes dual-substrate Monod kinetics for a steady-state biofilm with five solid and five dissolved components. The solid components are autotrophic denitrifying bacteria, autotrophic perchlorate-reducing bacteria, heterotrophic bacteria, inert biomass, and extracellular polymeric substances (EPS). The dissolved components are nitrate, perchlorate, hydrogen (H(2)), substrate-utilization-associated products, and biomass-associated products (BAP). The model explicitly considers four mechanisms involved in how three important operating conditions (H(2) pressure, nitrate loading, and perchlorate loading) affect nitrate and perchlorate removals: (1) competition for H(2), (2) promotion of PRB growth due to having two electron acceptors (nitrate and perchlorate), (3) competition between nitrate and perchlorate reduction for the same resources in the PRB: electrons and possibly reductase enzymes, and (4) competition for space in the biofilm. Two other special features are having H(2) delivered from the membrane substratum and solving directly for steady state using a novel three-step approach: finite-difference for approximating partial differential and/or integral equations, Newton-Raphson for solving nonlinear equations, and an iterative scheme to obtain the steady-state biofilm thickness. An example result illustrates the model's features. PMID:22191376

  14. Mars ecopoiesis test bed: on earth and on the red planet

    Science.gov (United States)

    Todd, Paul; Kurk, Michael Andy; Boland, Eugene; Thomas, David; Scherzer, Christopher

    2016-07-01

    The concept of autotrophic organisms serving as planetary pioneers as a precursor to terraforming has been under consideration for several decades, and the term Ecopoiesis was introduced by the ecopoiets C. Sagan, M. Avener, R. Haynes and C. McKay to call attention to this possibility. There is a continuing need for experimental evidence to support this concept, one of them being the need to evaluate the survivability of terrestrial autotrophic microbes in a planetary environment. For this and other purposes a planetary simulation facility was constructed and operated at Techshot, Inc. in Indiana, USA. This facility has an accumulated record of more than one year's worth of experimentation under simulated Mars conditions. In a recent study this facility was operated for five weeks in a mode that simulated 35 sols on and just below the surface of Mars at low latitude. The diurnal lighting period was 12 hours:12 hours using xenon arc light filtered to simulate the solar intensity and spectrum on the Martian surface. A daily temperature profile followed that recorded at low latitudes with night-time minima at -80 C and noontime maxima at +26 C. Atmosphere was CO _{2} at additive manufacturing with moving parts that simulate the components of the design. This mock-up assembly marks a starting point for a planetary surface probe for safe implantation on the surface of the Red Planet some decades in the future. This research was supported by NASA NIAC Phase I Grant "Mars Ecopoiesis Testbed" NNX14AM97G.

  15. [Analysis on Diversity of Denitrifying Microorganisms in Sequential Batch Bioreactor Landfill].

    Science.gov (United States)

    Li, Wei-Hua; Sun, Ying-Jie; Liu, Zi-Liang; Ma, Qiang; Yang, Qiang

    2016-01-15

    A denitrification functional microorganism gene clone library (amoA, nosZ) and the PCR-RFLP technology was constructed to investigate the microbial diversity of denitrifying microorganisms in the late period of stabilization of sequential batch bioreactor landfill. The results indicated that: the bacterial diversity of ammonia oxidizing bacteria in the aged refuse reactor was very high, and most of them were unknown groups, also, all bacteria were unculturable or had not been isolated. The phylogenetic analysis suggested that the dominant ammonia oxidizing bacteria were presumably Nitrosomonas of 6-Proteobacteria. The diversity of denitrifying bacteria in fresh refuse reactor was abundant, which mainly included Thauera and Thiobacillus of 6-Proteobacteria. As Thauera sp. has the denitrification characteristics under the condition of aerobic while Thiobacillus denitrificans has the autotrophic denitrification characteristics, it was speculated that aerobic denitrification and autotrophic denitrification might be the main pathways for nitrogen removal in the fresh refuse reactor at the late period of stabilization. Additionally, another group in the gene clone library of denitrifying bacteria may be classified as Bradyrhizobiaceae of alpha-Proteobacteria. PMID:27078976

  16. Inorganic Nitrogen Deposition and Its Impacts on N:P-Ratios and Lake Productivity

    Directory of Open Access Journals (Sweden)

    Dag O. Hessen

    2013-03-01

    Full Text Available The pronounced increase in the cycling and deposition of biologically reactive dissolved inorganic nitrogen (DIN over large areas globally not only cause increased concentrations of DIN in surface waters, but it will also affect nutrient ratios in rivers, lakes and coastal areas. This review addresses the flux and fate of DIN, focusing NO3 in lakes of boreal and alpine catchments. Not only DIN-deposition, but also catchment properties strongly affect the concentrations of NO3 in lakes, as well as NO3:total P (TP ratios. This ratio displays an extreme variability, and does also serve as an indicator of shift between N and P-limitation of aquatic autotrophs. A high share of forests and bogs in the catchment generally decreases NO3:total P ratios, while alpine and subalpine catchments with sparse vegetation cover may have high NO3:total P ratios, especially in regions with high DIN-deposition. Several empirical and experimental studies indicate a shift from an initial N to P-limitation, but for N-limited lakes, an increased growth of phytoplankton, periphytes and macrophytes may be accredited to elevated inputs of DIN. An intensified P-limitation may also be a consequence of elevated DIN-deposition. This P-limitation may again yield higher C:P-ratios in autotrophs with negative impacts on grazers and higher trophic levels.

  17. A Review on the Assessment of Stress Conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

    Science.gov (United States)

    Minhas, Amritpreet K.; Hodgson, Peter; Barrow, Colin J.; Adholeya, Alok

    2016-01-01

    Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids) under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C) such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME), and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions. PMID:27199903

  18. Enrichment of anammox from activated sludge and its application in the CANON process.

    Science.gov (United States)

    Third, K A; Paxman, J; Schmid, M; Strous, M; Jetten, M S M; Cord-Ruwisch, R

    2005-02-01

    A microbial culture capable of actively oxidizing ammonium to dinitrogen gas in the absence of oxygen, using nitrite as the electron acceptor, was enriched from local activated sludge (Western Australia) in activity achieved by the anaerobic culture was 0.26 mmol NH (4) (+) (g biomass)(-1) h(-1) (0.58 kg total-N m(-3) day(-1)). Qualitative FISH analysis (fluorescence in situ hybridization) confirmed the phylogenetic position of the enriched microorganism as belonging to the order Planctomycetales, in which all currently identified anammox strains fall. Preliminary FISH analysis suggests the anammox strain belongs to the same phylogenetic group as the Candidatus 'Brocadia anammoxidans' strain discovered in the Netherlands. However, there are quite a few differences in the target sites for the more specific probes of these organisms and it is therefore likely to represent a new species of anammox bacteria. A small amount of aerobic ammonium-oxidizing biomass was inoculated into the anammox reactor (10% v/v) to initiate completely autotrophic nitrogen removal over nitrite (the CANON process) in chemostat culture. The culture was always under oxygen limitation and no organic carbon was added. The CANON reactor was operated as an intermittently aerated system with 20 min aerobiosis and 30 min anaerobiosis, during which aerobic and anaerobic ammonium oxidation were performed in sequential fashion, respectively. Anammox was not inhibited by repeated intermittent exposure to oxygen, allowing sustained, completely autotrophic ammonium removal (0.08 kg N m(-3) day(-1)) for an extended period of time. PMID:15735941

  19. Whole-system metabolism and CO2 fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean

    Directory of Open Access Journals (Sweden)

    A. V. Borges

    2004-10-01

    Full Text Available The relationship between whole-system metabolism estimates based on planktonic and benthic incubations (bare sediments and seagrass, Posidonia oceanica meadows, and CO2 fluxes across the air-sea interface were examined in the Bay of Palma (Mallorca, Spain during two cruises in March and June 2002. Moreover, planktonic and benthic incubations were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the bay. From the annual study, results showed a contrast between the planktonic compartment, which was heterotrophic during most of the year, except for occasional bloom episodes, and the benthic compartment, which was slightly autotrophic. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the excess respiration of the planktonic compartment in shallow waters (2 fields and fluxes across the bay observed during the two extensive cruises in 2002. Finally, dissolved inorganic carbon and oxygen budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow.

  20. MOVEMENT OF CADMIUM AND LEAD IN ANTHROPOGENICALLY FORMED TROPHIC CHAINS OF A PASTURE TYPE

    Directory of Open Access Journals (Sweden)

    B BAYKOV

    2004-04-01

    Full Text Available An investigation on the movement of Lead (Pb and cadmium (Cd in a trophic chain in 2 villages (industrial polluted and non polluted has been conducted. The contents of the 2 heavy metals in the soil, food and in different organs of young kids, so as their transfer in the 3 trophic levels (using different static and dynamic methods of recalculation have been established. The authors show, that it is expedient to determine quantitatively the chemical heterogeneity at the heterotrophic levels applying two criteria: along with the dynamic criterion “Clarc of concentration”(Cc, used up to know, to include also “Factor of bioaccumulation” (FB, which shows the real value of accumulation or dispersal of the chemical element according to its content in soil or at the trophic level of the autotrophic organisms. The increased Cc of lead /4,72/ and cadmium /49,14/ in soil is not the reason for the concentration in the nutrition chain at the level of the autotrophic organisms and at the level of the organisms phytophages /kids/. The studies of the FB show that the technogenically high Clarc of lead and cadmium in the ecotope is the reason for some changes in the metabolism, enabling the dispersal of lead along the trophic chain, the values falling down to 0,05 – 0,02 compared to its content in the ecotope, and, of cadmium – down to 0,03 – 0,15 in the tested organs and tissues.

  1. Picoplankton Community Composition by CARD-FISH and Flow Cytometric Techniques: A Preliminary Study in Central Adriatic Sea Water

    Directory of Open Access Journals (Sweden)

    Anita Manti

    2012-01-01

    Full Text Available Data concerning picoplanktonic community composition and abundance in the Central Adriatic Sea are presented in an effort to improve the knowledge of bacterioplankton and autotrophic picoplankton and their seasonal changes. Flow cytometry analyses revealed the presence of two distinct bacteria populations: HNA and LNA cells. HNA cells showed an explicit correlation with viable and actively respiring cells. The study of viability and activity may increase our knowledge of the part that contributes really to the remineralization and bacterial biomass production. Authotrophic picoplankton abundance, especially picocyanobacteria, was strongly influenced by seasonality, indicating that light availability and water temperature are very important regulating factors. In terms of total carbon biomass, the main contribution came from heterotrophic bacteria with a lower contribution from autotrophic picoplankton. CARD-FISH evidenced, within the Eubacteria domain, the dominance of members of the phyla Alphaproteobacteria, with a strong contribution from SAR11clade, followed by Cytophaga-Flavobacterium and Gammaproteobacteria. The bacterial groups detected contributed differently depending when the sample was taken, suggesting possible seasonal patterns. This study documents for the first time picoplankton community composition in the Central Adriatic Sea using two different approaches, FCM and CARD-FISH, and could provide preliminary data for future studies.

  2. Dynamics of component carbon fluxes in a semi-arid Acacia woodland, central Australia

    Science.gov (United States)

    Cleverly, James; Boulain, Nicolas; Villalobos-Vega, Randol; Grant, Nicole; Faux, Ralph; Wood, Cameron; Cook, Peter G.; Yu, Qiang; Leigh, Andrea; Eamus, Derek

    2013-07-01

    Vast areas in the interior of Australia are exposed to regular but infrequent periods of heavy rainfall, interspersed with long periods at high temperatures, but little is known of the carbon budget of these remote areas or how they respond to extreme precipitation. In this study, we applied three methods to partition net ecosystem photosynthesis into gross primary production (GPP) and ecosystem respiration (Re) during two years of contrasting rainfall. The first year was wet (>250 mm above average rainfall), while little precipitation fell during the second year (>100 mm below average). During the first year of study, rates of GPP were large (793 g C m-2 yr-1) in this semi-arid Mulga (Acacia aneura) and grass savanna due to complementary photosynthetic responses by the canopy and C4 understorey to cycles of heavy rainfall. Patterns in GPP during the summer and autumn matched those in leaf area index (LAI), photosynthetic activity, and autotrophic respiration. During the dry year, small but positive photosynthetic uptake by Mulga contributed to the neutral carbon budget (GPP / Re = 1.06 ± 0.03). Small rates of photosynthesis by evergreen Mulga when dry were supported by storage of soil moisture above a relatively shallow hardpan. Little soil organic matter (1.1%) was available to support heterotrophic respiration (Rh) without input of fresh substrate. The two largest sources of Re in this study were autotrophic respiration by the seasonal understorey and Rh through decomposition of fresh organic matter supplied by the senescent understorey.

  3. Few apparent short-term effects of elevated soil temperature and increased frequency of summer precipitation on the abundance and taxonomic diversity of desert soil micro- and meso-fauna

    Science.gov (United States)

    Darby, B.J.; Neher, D.A.; Housman, D.C.; Belnap, J.

    2011-01-01

    Frequent hydration and drying of soils in arid systems can accelerate desert carbon and nitrogen mobilization due to respiration, microbial death, and release of intracellular solutes. Because desert microinvertebrates can mediate nutrient cycling, and the autotrophic components of crusts are known to be sensitive to rapid desiccation due to elevated temperatures after wetting events, we studied whether altered soil temperature and frequency of summer precipitation can also affect the composition of food web consumer functional groups. We conducted a two-year field study with experimentally-elevated temperature and frequency of summer precipitation in the Colorado Plateau desert, measuring the change in abundance of nematodes, protozoans, and microarthropods. We hypothesized that microfauna would be more adversely affected by the combination of elevated temperature and frequency of summer precipitation than either effect alone, as found previously for phototrophic crust biota. Microfauna experienced normal seasonal fluctuations in abundance, but the effect of elevated temperature and frequency of summer precipitation was statistically non-significant for most microfaunal groups, except amoebae. The seasonal increase in abundance of amoebae was reduced with combined elevated temperature and increased frequency of summer precipitation compared to either treatment alone, but comparable with control (untreated) plots. Based on our findings, we suggest that desert soil microfauna are relatively more tolerant to increases in ambient temperature and frequency of summer precipitation than the autotrophic components of biological soil crust at the surface.

  4. RubisCO-based CO2 fixation and C1 metabolism in the actinobacterium Pseudonocardia dioxanivorans CB1190.

    Science.gov (United States)

    Grostern, Ariel; Alvarez-Cohen, Lisa

    2013-11-01

    Pseudonocardia is an actinobacterial genus of interest due to its potential biotechnological, medical and environmental remediation applications, as well as for the ecologically relevant symbiotic relationships it forms with attine ants. Some Pseudonocardia spp. can grow autotrophically, but the genetic basis of this capability has not previously been reported. In this study, we examined autotrophy in Pseudonocardia dioxanivorans CB1190, which can grow using H2 and CO2, as well as heterotrophically. Genomic and transcriptomic analysis of CB1190 cells grown with H2/bicarbonate implicated the Calvin-Benson-Bassham (CBB) cycle in growth-supporting CO2 fixation, as well as a [NiFe] hydrogenase-encoding gene cluster in H2 oxidation. The CBB cycle genes are evolutionarily most related to actinobacterial homologues, although synteny has not been maintained. Ribulose-1,5-bisphosphate carboxylase activity was confirmed in H2/bicarbonate-grown CB1190 cells and was detected in cells grown with the C1 compounds formate, methanol and carbon monoxide. We also demonstrated the upregulation of CBB cycle genes upon exposure of CB1190 to these C1 substrates, and identified genes putatively involved in generating CO2 from the C1 substrates by using RT-qPCR. Finally, the potential for autotrophic growth of other Pseudonocardia spp. was explored, and the ecological implications of autotrophy in attine ant- and plant root-associated Pseudonocardia discussed. PMID:23663433

  5. Endolithic bacterial communities in rock coatings from Kärkevagge, Swedish Lapland.

    Science.gov (United States)

    Marnocha, Cassandra L; Dixon, John C

    2014-11-01

    Rock coatings in Kärkevagge, Swedish Lapland, are widespread and mineralogically diverse. A preliminary study of the rock coatings revealed higher than expected bacterial diversity for an endolithic environment in the arctic. Using 454 Roche pyrosequencing of the 16S rRNA gene, nine rock coating samples from three different coating mineralogies were sequenced. The three coating types include Fe films of goethite and hematite, sulfate crusts of jarosite and gypsum, and aluminum glazes of basaluminite and alunite. Over 20,000 quality sequences were analyzed, and over 2800 operational taxonomic units were identified. Diversity indices and richness estimates confirmed high levels of diversity, particularly in the sulfate crusts with diversity indices at the level of complex soils. Inferred physiology shows the presence of both heterotrophs and autotrophs, with genera of autotrophic Fe and S metabolisms present in at least 2% of the total for each coating type. The most common phyla included Proteobacteria, Acidobacteria, and Actinobacteria - all common soil taxa. Coatings also showed distinct community structure between coating mineralogies. Given the diversity in coating types found in areas receiving the same chemical and environmental inputs, the distinct microbial communities suggest a biological role in coating development. PMID:25118061

  6. Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process

    Energy Technology Data Exchange (ETDEWEB)

    Sahinkaya, Erkan, E-mail: erkansahinkaya@yahoo.com [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey); Kilic, Adem [Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa (Turkey); Calimlioglu, Beste; Toker, Yasemin [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey)

    2013-11-15

    Highlights: • Simultaneous heterotrophic and autotrophic denitrification was stimulated. • Simultaneous bioreduction of nitrate and chromate was achieved. • Total chromium decreased <50 μg/L when the influent Cr(VI) was ≤5 mg/L. -- Abstract: This study aims at evaluating simultaneous chromate and nitrate reduction using sulfur-based mixotrophic denitrification process in a column reactor packed with elemental sulfur and activated carbon. The reactor was supplemented with methanol at C/N ratio of 1.33 or 2. Almost complete denitrification was achieved at influent NO{sub 3}{sup −}–N and Cr(VI) concentrations of 75 mg/L and 10 mg/L, respectively, and 3.7 h HRT. Maximum denitrification rate was 0.5 g NO{sub 3}{sup −}–N/(L.d) when the bioreactor was fed with 75 mg/L NO{sub 3}{sup −}–N, 150 mg/L methanol and 10 mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 μg/L provided that influent Cr(VI) concentration was equal or below 5 mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed.

  7. Using Partial Genomic Fosmid Libraries for Sequencing CompleteOrganellar Genomes

    Energy Technology Data Exchange (ETDEWEB)

    McNeal, Joel R.; Leebens-Mack, James H.; Arumuganathan, K.; Kuehl, Jennifer V.; Boore, Jeffrey L.; dePamphilis, Claude W.

    2005-08-26

    Organellar genome sequences provide numerous phylogenetic markers and yield insight into organellar function and molecular evolution. These genomes are much smaller in size than their nuclear counterparts; thus, their complete sequencing is much less expensive than total nuclear genome sequencing, making broader phylogenetic sampling feasible. However, for some organisms it is challenging to isolate plastid DNA for sequencing using standard methods. To overcome these difficulties, we constructed partial genomic libraries from total DNA preparations of two heterotrophic and two autotrophic angiosperm species using fosmid vectors. We then used macroarray screening to isolate clones containing large fragments of plastid DNA. A minimum tiling path of clones comprising the entire genome sequence of each plastid was selected, and these clones were shotgun-sequenced and assembled into complete genomes. Although this method worked well for both heterotrophic and autotrophic plants, nuclear genome size had a dramatic effect on the proportion of screened clones containing plastid DNA and, consequently, the overall number of clones that must be screened to ensure full plastid genome coverage. This technique makes it possible to determine complete plastid genome sequences for organisms that defy other available organellar genome sequencing methods, especially those for which limited amounts of tissue are available.

  8. Methanogenesis-induced pH–Eh shifts drives aqueous metal(loid) mobility in sulfide mineral systems under CO2 enriched conditions

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Omar R.; Qafoku, Nikolla; Cantrell, Kirk J.; Wilkins, Michael J.; Brown, Christopher F.

    2016-01-15

    Accounting for microbially-mediated CO2 transformation is pivotal to assessing geochemical implications for elevated CO2 in subsurface environments. A series of batch-reactor experiments were conducted to decipher links between autotrophic methanogenesis, CO2 dynamics and aqueous Fe, As and Pb concentrations in the presence of sulfide minerals. Microbially-mediated solubility-trapping followed by pseudo-first order reduction of HCO3- to CH4 (k’ = 0.28-0.59 d-1) accounted for 95% of the CO2 loss from methanogenic experiments. Bicarbonate-to-methane reduction was pivotal in the mitigation of CO2-induced acidity (~1 pH unit) and enhancement of reducing conditions (Eh change from -0.215 to -0.332V ). Methanogenesis-associated shifts in pH-Eh values showed no significant effect on aqueous Pb but favored, 1) increased aqueous As as a result of microbially-mediated dissolution of arsenopyrite and 2) decreased aqueous Fe due to mineral-trapping of CO2-mobilized Fe as Fe-carbonate. Its order of occurrence (and magnitude), relative to solubility- and mineral-trapping, highlighted the potential for autotrophic methanogenesis to modulate both carbon sequestration and contaminant mobility in CO2-impacted subsurface environments.

  9. Discovery of a Katablepharis sp. in the Columbia River estuary that is abundant during the spring and bears a unique large ribosomal subunit sequence element

    Science.gov (United States)

    Kahn, Peter; Herfort, Lydie; Peterson, Tawnya D; Zuber, Peter

    2014-01-01

    Heterotrophic protists play significant roles in pelagic food webs as bacterivorous and herbivorous consumers. However, heterotrophic protists—unlike autotrophic ones—are often difficult to track since they tend to lack features such as photosynthetic pigments that allow for remote sensing or for bulk characterization. Difficulty in the identification of heterotrophic protists has often resulted in lumping them into broad groups, but there is a strong need to develop methods that increase the spatial and temporal resolution of observations applied to particular organisms in order to discover the drivers of population structure and ecological function. In surveys of small subunit rRNA, gene (SSU) sequences of microbial eukaryotes from the Columbia River to the Pacific Ocean, the heterotrophic flagellate Katablepharis sp. were found to dominate protist assemblages (including autotrophic and heterotrophic fractions) in the spring, prior to the freshet. We discovered a 332 base pair unique sequence element (USE) insertion in the large subunit rRNA gene (28S) that is not present in other katablepharids or in any other eukaryote. Using this USE, we were able to detect Katablepharis within mixed assemblages in river, estuarine, and oceanic samples and determine spatial and temporal patterns in absolute abundance through quantitative PCR and fluorescence in situ hybridization. Given their high abundance and repeatable temporal patterns of occurrence, we hypothesize that the Columbia River Estuary Katablepharis (Katablepharis CRE) plays an important role in estuarine biogeochemical and ecosystem function. PMID:25168204

  10. Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

    Directory of Open Access Journals (Sweden)

    Esparza Mario

    2010-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2. Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. Results Four gene clusters (termed cbb1-4 in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39 and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19. Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II Rubis

  11. CO2 fluxes exchanged by a 4-year crop rotation cycle.

    Science.gov (United States)

    Aubinet, M.; Moureaux, C.; Bodson, B.; Dufranne, D.; Heinesch, B.; Suleau, M.; Vancutsem, F.; Vilret, A.

    2009-04-01

    This study analyses carbon fluxes exchanged by a production crop during a four year cycle. Between 2004 and 2008, the successive crops were sugar beet, winter wheat, potato and again winter wheat. Eddy covariance, automatic and manual soil chamber, leaf diffusion and biomass measurements were performed continuously in order to obtain the daily and seasonal Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP), Total Ecosystem Respiration (TER), Net Primary Productivity (NPP), Autotrophic Respiration, Heterotrophic Respiration and Net Biome Production (NBP). The whole cycle budget showed that NEE was negative and the rotation behaved as a sink of 1.59 kgC m-2 over the 4-year rotation. However, if exports were deducted from the budget, the crop would become a small source of 0.22 (+/- 0.14) kgC m-2, which also suggests that the crop soil carbon content decreased. This could partly be explained by the crop management, as neither farmyard manure nor slurry had been applied to the crop for more than 10 years and as cereal straw had been systematically exported for livestock. This result is also strongly dependent on climate: the fluxes were subjected to a large inter-annual variability due to differences between crops but also to climate variability. In particular, the mild winter and the dry spring underwent in 2007 induced an increase of the biomass fraction that returned to the soil, at the expense of harvested biomass. If 2007 had been a ‘normal' year, the carbon emission by the crop rotation would have been twice as great. This is analysed more in detail in a companion presentation (Dufranne et al., this session). The impacts of some farmer interventions were quantified. In particular, the impact of ploughing was found to be limited both in intensity (1 to 2 micromol m-2 s-1) and duration (not more than 1 day). Seasonal budgets showed that, during cropping periods, the TER/GPP ratio varied between 40 and 60% and that TER was dominated mainly by the

  12. N{sub 2}O production pathways in the subtropical acid forest soils in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinbo [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Cai Zucong, E-mail: zccai@mail.issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Zhu Tongbin [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2011-07-15

    To date, N{sub 2}O production pathways are poorly understood in the humid subtropical and tropical forest soils. A {sup 15}N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N{sub 2}O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N{sub 2}O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N{sub 2}O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N{sub 2}O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N{sub 2}O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N{sub 2}O product ratios from nitrification. The ratio of N{sub 2}O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: {yields} We studied N{sub 2}O production pathways in subtropical acid forest soil under aerobic conditions. {yields} Denitrification was the main source of N{sub 2}O production in subtropical acid forest soils. {yields} Heterotrophic nitrification accounted for 27.3%-41.8% of N{sub 2}O production. {yields} While, contribution of autotrophic nitrification to N{sub 2}O production was little. {yields} Ratios of N{sub 2}O-N emission from nitrification were higher than those in most previous references.

  13. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2−}, NO{sub 3}{sup −}-N, NO{sub 2}{sup −}-N, and Ac{sup −}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup −1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2−}), nitrate (NO{sub 3}{sup −}) and acetate (Ac{sup −}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2−} concentration, S{sup 2−}/NO{sub 3}{sup −}-N ratio and Ac{sup −}-C/NO{sub 3}{sup −}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup −} reduction to NO{sub 2}{sup −}) was inhibited by S{sup 2−} compared with the denitritation step (NO{sub 2}{sup −} reduction to N{sub 2}). Also, the S{sup 2−} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup −} as electron acceptor than that with NO{sub 3}{sup −} as electron acceptor. NO{sub 3}{sup −} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2−}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of

  14. Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas

    International Nuclear Information System (INIS)

    Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium 14C-bicarbonate and sodium 3H-acetate and size fractionated to determine the size structure of planktonic autotrophy and microheterotrophy in DeGray Reservoir, an oligotrophic impoundment of the Caddo River in south-central Arkansas. Size distributions of autotrophy and microheterotrophy were remarkably uniform seasonally, vertically within the water column, and along the longitudinal axis of the reservoir despite significant changes in environmental conditions. Planktonic autotrophy was dominated by small algal cells with usually >50% of the photosynthetic carbon uptake accounted for by organisms 75% of the planktonic microheterotrophy. Longitudinal patterns in autotrophic and microheterotrophic activities associated with >3-μm and >1-μm size fractions, respectively, suggest an uplake to downlake shift from riverine to lacustrine environmental influences within the reservoir. 83 references, 7 figures

  15. COUPLED PHYSICAL-ECOLOGICAL MODELLING IN THE CENTRAL PART OF JIAOZHOU BAY Ⅱ. COUPLED WITH AN ECOLOGICAL MODEL

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Sharples' 1-D physical model employing tide-wind driven turbulence closure and surface heating-cooling physics, was coupled with an ecological model with 9-biochemical components: phytoplankton, zooplankton, shellfish, autotrophic and heterotrophic bacterioplankton, dissolved organic carbon (DOC), suspended detritus and sinking particles to simulate the annual evolution of ecosystem in the central part of Jiaozhou Bay. The coupled modeling results showed that the phytoplankton shading effect could reduce seawater temperature by 2℃, so that photosynthesis efficiency should be less than 8%; that the loss of phytoplankton by zooplankton grazing in winter tended to be compensated by phytoplankton advection and diffusion from the outside of the Bay; that the incident irradiance intensity could be the most important factor for phytoplankton growth rate; and that it was the bacterial secondary production that maintained the maximum zooplankton biomass in winter usually observed in the 1990s, indicating that the microbial food loop was extremely important for ecosystem study of Jiaozhou Bay.

  16. Partitioning CO2 fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Davidson, Eric [Univ. of Arizona, Tucson, AZ (United States); Finzi, Adrien [Boston Univ., MA (United States); Wehr, Richdard [Harvard Univ., Cambridge, MA (United States); Moorcroft, Paul [Harvard Univ., Cambridge, MA (United States)

    2016-01-28

    1. Objectives This project combines automated in situ observations of the isotopologues of CO2 with root observations, novel experimental manipulations of belowground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. aboveground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: A. Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics ; B. Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated belowground using measurements of root growth and indices of belowground autotrophic vs. heterotrophic respiration (via trenched plots and isotope measurements); C. Testing whether plant allocation of carbon belowground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and D. Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2). 2. Highlights Accomplishments: • Our isotopic eddy flux record has completed its 5th full year and has been used to independently estimate ecosystem-scale respiration and photosynthesis. • Soil surface chamber isotopic flux measurements were carried out during three growing seasons, in conjunction with a trenching manipulation. Key findings to date (listed by objective): A. Partitioning of Net Ecosystem Exchange: 1. Ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light (the “Kok effect”) at the ecosystem scale. 2. Because it neglects the Kok effect, the standard NEE partitioning approach overestimates ecosystem photosynthesis (by ~25%) and

  17. Partitioning CO2 fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Davidson, Eric [Univ. of Arizona, Tucson, AZ (United States); Finzi, Adrien [Univ. of Arizona, Tucson, AZ (United States); Wehr, Richard [Univ. of Arizona, Tucson, AZ (United States); Moorcroft, Paul [Univ. of Arizona, Tucson, AZ (United States)

    2016-01-28

    1. Objectives This project combines automated in situ observations of the isotopologues of CO2 with root observations, novel experimental manipulations of belowground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. aboveground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: A. Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics ; B. Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated belowground using measurements of root growth and indices of belowground autotrophic vs. heterotrophic respiration (via trenched plots and isotope measurements); C. Testing whether plant allocation of carbon belowground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and D. Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2). 2. Highlights Accomplishments: • Our isotopic eddy flux record has completed its 5th full year and has been used to independently estimate ecosystem-scale respiration and photosynthesis. • Soil surface chamber isotopic flux measurements were carried out during three growing seasons, in conjunction with a trenching manipulation. Key findings to date (listed by objective): A. Partitioning of Net Ecosystem Exchange: 1. Ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light (the “Kok effect”) at the ecosystem scale. 2. Because it neglects the Kok effect, the standard NEE partitioning approach overestimates ecosystem

  18. Bacterial community structure in High-Arctic snow and freshwater as revealed by pyrosequencing of 16S rRNA genes and cultivation

    DEFF Research Database (Denmark)

    Møller, Annette; Søborg, Ditte Andreasen; Al-Soud, Waleed Abu;

    2013-01-01

    controlled the distribution of the Cyanobacteria and algae in the snow while carbon and nitrogen fixed by these autotrophs in turn fed the heterotrophic bacteria. In the lake, a probable lower light input relative to snow resulted in low numbers of Cyanobacteria and chloroplasts and, hence, limited input......The bacterial community structures in High-Arctic snow over sea ice and an ice-covered freshwater lake were examined by pyrosequencing of 16S rRNA genes and 16S rRNA gene sequencing of cultivated isolates. Both the pyrosequence and cultivation data indicated that the phylogenetic composition...... of the microbial assemblages was different within the snow layers and between snow and freshwater. The highest diversity was seen in snow. In the middle and top snow layers, Proteobacteria, Bacteroidetes and Cyanobacteria dominated, although Actinobacteria and Firmicutes were relatively abundant also. High numbers...

  19. Facile Carbon Fixation to Performic Acids by Water-Sealed Dielectric Barrier Discharge

    Science.gov (United States)

    Kawasaki, Mitsuo; Morita, Tatsuo; Tachibana, Kunihide

    2015-10-01

    Carbon fixation refers to the conversion of carbon dioxide (CO2) to organic materials, as commonly performed in nature through photosynthesis by plants and other autotrophic organisms. The creation of artificial carbon fixation processes is one of the greatest challenges for chemistry to solve the critical environmental issue concerning the reduction of CO2 emissions. We have developed an electricity-driven facile CO2 fixation process that yields performic acid, HCO2OH, from CO2 and water at neutral pH by dielectric barrier discharge with an input electric power conversion efficiency of currently 0.2-0.4%. This method offers a promising future technology for artificial carbon fixation on its own, and may also be scaled up in combination with e.g., the post-combustion CO2 capture and storage technology.

  20. Application of Microbial Products to Promote Electrodialytic Remediation of Heavy Metal Contaminated Soil

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland

    2006-01-01

    In urban areas of Denmark, Pb is the most frequently observed soil-contaminant together with PAHs. Comprehensive legislation has been imposed to reduce Pb-exposure in the Danish society. The major use of Pb is at present in accumulators, which are being collected and reused. Since the use of Pb...... by other researchers in the group. Therefore the possibility of treating the fine fraction of Pb-contaminated soils by suspended EDR was investigated. This technology was intended for combination with conventional soil washing, in which the lack of a treatment method for the remaining soil-fines has been...... using a number of reactors in series, where the initial reactor works at the highest possible removal rate, and the final reactor works at the target Pb-concentration. Application of microbially produced siderophores, autotrophic leaching, heterotrophic leaching and biosurfactants were identified...

  1. AN ECOSYSTEM MODEL OF FISHERIES AND NUTRIENT ENRICHMENT

    DEFF Research Database (Denmark)

    Nguyen, Thanh Viet; Vestergaard, Niels

    2009-01-01

      Economic models of fishery largely ignore the linkages to lower trophic levels. In particular, environmental data and other bottom-up information is widely disregarded. Nor are changes in physical environment (bottom-up) alongside both exogenous and endogenous environmental effects included in...... the general ecosystem models. The objectives of this paper are modeling the impacts of nutrient enrichment on fisheries; particularly the impacts on consumer stocks and the fisheries based on these stocks are presented. We consider an aquatic ecosystem with four components: producers (autotrophs......), consumers (herbivores, carnivores), nonliving matter and pollution sources. The interactions between nutrients-producers, producers- consumers are assumed following the Holling type II functional response. Pollution sources cause excess nutrients which linked to increase primary productivity, hypoxia and...

  2. Stability and optimal control for some classes of tritrophic systems.

    Science.gov (United States)

    Galbusera, Luca; Pasquali, Sara; Gilioli, Gianni

    2014-04-01

    The objective of this paper is to study an optimal resource management problem for some classes of tritrophic systems composed by autotrophic resources (plants), bottom level consumers (herbivores) and top level consumers (humans). The first class of systems we discuss are linear chains, in which biomass flows from plants to herbivores, and from herbivores to humans. In the second class of systems humans are omnivorous and hence compete with herbivores for plant resources. Finally, in the third class of systems humans are omnivorous, but the plant resources are partitioned so that humans and herbivores do not complete for the same ones. The three trophic chains are expressed as Lotka-Volterra models, which seems to be a suitable choice in contexts where there is a shortage of food for the consumers. Our model parameters are taken from the literature on agro-pastoral systems in Sub-Saharan Africa. PMID:24245717

  3. [Significance of hydrobiont persistent properties for symbiotic interactions].

    Science.gov (United States)

    Nemtseva, N V

    2012-01-01

    Significance of symbiotic relations formed by associative symbiosis type for autochthonous and allochthonous microflora of natural water bodies is shown. Generality of symbiotic interaction mechanisms of symbionts in limnetic and halophilous communities provided by secreted factors of natural resistance from the side of the host, and by factors of persistence from the side of symbionts is proven based on a set of examples. Features of operation of lysozyme-antilysozyme, histon-antihiston, hydrogen peroxide-catalase functional systems in symbiotic interactions of autotrophic and heterotrophic components of hydrobiocenosis with dominant and associative microflora are presented. Associative microflora of allochthonous origin was shown to actively use the ecologically formed system of interaction between hydrobionts that facilitates survival of these microorganisms and preservation of their persistent potential, and as a result leads to biocenosis disorders. The knowledge obtained open new possibilities and perspectives of research of sanitary and ecological aspects of vital activity of aquatic biocenoses. PMID:22937711

  4. Immobilization of activated sludge using improved polyvinyl alcohol (PVA) gel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microbial immobilization method using polyvinyl alcohol (PVA) gel as an immobilizing material was improved and used for entrapment of activated sludge. The OUR (oxygen uptake rate) was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads was prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media (containing 250 mg/L COD and 25 mg/L NH4+-N). The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.

  5. Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers

    Science.gov (United States)

    Xu, Henglong; Min, Gi-Sik; Choi, Joong-Ki; Zhu, Mingzhuang; Jiang, Yong; Al-Rasheid, Khaled A. S.

    2010-01-01

    The ecological processes and interrelationships between protists, either autotrophic or heterotrophic, and environmental factors in mariculture ponds are largely unknown. This study investigated the temporal dynamics of potentially harmful dinoflagellate, Prorocentrum minimum (Pavillard) Schiller, and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao, Northern China. P. minimum occurred frequently in low numbers from June to August, followed by a sharp increase from the middle of August, reaching a single maximum peak value of 2.2×105 cells L-1 in October. Temporal variation in abundance was positively correlated with dissolved nitrogen, but showed a significant inverse relationship to abundance of the dominant ciliates, Tintinnopsis lohmanni and Askenasia stellaris. The results provide statistical evidence that the number of P. minimum increased with increasing nitrogen, and the suppression or shortening of algal bloom may be associated with protozoan grazers, such as Tintinnopsis lohmanni, in mariculture ponds.

  6. Generation and Evaluation of a Genome-Scale Metabolic Network Model of Synechococcus elongatus PCC7942

    Directory of Open Access Journals (Sweden)

    Julián Triana

    2014-08-01

    Full Text Available The reconstruction of genome-scale metabolic models and their applications represent a great advantage of systems biology. Through their use as metabolic flux simulation models, production of industrially-interesting metabolites can be predicted. Due to the growing number of studies of metabolic models driven by the increasing genomic sequencing projects, it is important to conceptualize steps of reconstruction and analysis. We have focused our work in the cyanobacterium Synechococcus elongatus PCC7942, for which several analyses and insights are unveiled. A comprehensive approach has been used, which can be of interest to lead the process of manual curation and genome-scale metabolic analysis. The final model, iSyf715 includes 851 reactions and 838 metabolites. A biomass equation, which encompasses elementary building blocks to allow cell growth, is also included. The applicability of the model is finally demonstrated by simulating autotrophic growth conditions of Synechococcus elongatus PCC7942.

  7. Anammox transited from denitrification in upflow biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-hui; ZHENG Ping; HUA Yu-mei

    2004-01-01

    Anammox was successfully transited from heterotrophic denitrification and autotrophic denitrification in two upflow biofilm reactors, respectively. The results showed that the volumetric loading rate and nitrogen removal efficiency in the reactor transited from heterotrophic denitrification were higher than that in its counterpart. When the hydraulic retention time was 12 h or so, the total nitrogen loading rate was about 0.609 kg N/(m3·d), and the effluent ammonia and nitrite concentrations were less than 8.5 mg/L and 2.5 mg/L, respectively. The upflow anammox biofilm reactor was capable of keeping and accumulating the slow-growing bacteria efficiently. During operation of the reactor, the biomass color was gradually turned from brownish to red, and the ratio of ammonia consumption, nitrite consumption and nitrate production approached the theoretical one. These changes could be used as an indicator for working state of the reactor.

  8. The δ15N and δ18O values of N2O produced during the co-oxidation of ammonia by methanotrophic bacteria

    Science.gov (United States)

    Mandernack, Kevin W.; Mills, Christopher T.; Johnson, Craig A.; Rahn, Thomas; Kinney, Chad

    2009-01-01

    In order to determine if the δ15N and δ18O values of N2O produced during co-oxidation of NH4+ by methanotrophic (methane oxidizing) bacteria can be isotopically distinguished from N2O produced either by autotrophic nitrifying or denitrifying bacteria, we conducted laboratory incubation experiments with pure cultures of methanotrophic bacteria that were provided NH4Cl as an oxidation substrate. The N2O produced during NH4+ oxidation by methanotrophic bacteria showed nitrogen isotope fractionation between NH4+ and N2O (εN2O–NH4+) of − 48 and − 55‰ for Methylomonas methanica and Methylosinus trichosporium, OB3b respectively. These large fractionations are similar to those previously measured for autotrophic nitrifying bacteria and consistent with N2O formation by multiple rate limiting steps that include NH4+oxidation by the methane monooxygenase enzyme and reduction of NO2− to N2O. Consequently, N2O formed by NH4+ oxidation via methanotrophic or autotrophic nitrifying bacteria might generally be characterized by lower δ15NN2O values than that formed by denitrificaiton, although this also depends on the variability of δ15N of available nitrogen sources (e.g., NH4+, NO3−, NO2−). Additional incubations with M. trichosporium OB3b at high and low CH4 conditions in waters of different δ18O values revealed that 19–27% of the oxygen in N2O was derived from O2 with the remainder from water. The biochemical mechanisms that could explain this amount of O2 incorporation are discussed. The δ18O of N2O formed under high CH4 conditions was ~ + 15‰ more positive than that formed under lower CH4 conditions. This enrichment resulted in part from the incorporation of O2 into N2O that was enriched in 18O due to an isotope fractionation effect of − 16.1 ± 2.0‰ and − 17.5 ± 5.4‰ associated with O2 consumption during the high and low methane concentration incubations, respectively. Therefore, N2O formed by NH4+

  9. C1-carbon sources for chemical and fuel production by microbial gas fermentation.

    Science.gov (United States)

    Dürre, Peter; Eikmanns, Bernhard J

    2015-12-01

    Fossil resources for production of fuels and chemicals are finite and fuel use contributes to greenhouse gas emissions and global warming. Thus, sustainable fuel supply, security, and prices necessitate the implementation of alternative routes to the production of chemicals and fuels. Much attention has been focussed on use of cellulosic material, particularly through microbial-based processes. However, this is still costly and proving challenging, as are catalytic routes to biofuels from whole biomass. An alternative strategy is to directly capture carbon before incorporation into lignocellulosic biomass. Autotrophic acetogenic, carboxidotrophic, and methanotrophic bacteria are able to capture carbon as CO, CO2, or CH4, respectively, and reuse that carbon in products that displace their fossil-derived counterparts. Thus, gas fermentation represents a versatile industrial platform for the sustainable production of commodity chemicals and fuels from diverse gas resources derived from industrial processes, coal, biomass, municipal solid waste (MSW), and extracted natural gas. PMID:25841103

  10. Calcification generates protons for nutrient and bicarbonate uptake

    Science.gov (United States)

    McConnaughey, T. A.; Whelan, J. F.

    1997-03-01

    The biosphere's great carbonate deposits, from caliche soils to deep-sea carbonate oozes, precipitate largely as by-products of autotrophic nutrient acquisition physiologies. Protons constitute the critical link: Calcification generates protons, which plants and photosynthetic symbioses use to assimilate bicarbonate and nutrients. A calcium ATPase-based "trans" mechanism underlies most biological calcification. This permits high calcium carbonate supersaturations and rapid carbonate precipitation. The competitive advantages of calcification become especially apparent in light and nutrient-deficient alkaline environments. Calcareous plants often dominate the lower euphotic zone in both the benthos and the plankton. Geographically and seasonally, massive calcification concentrates in nutrient-deficient environments including alkaline soils, coral reefs, cyanobacterial mats and coccolithophorid blooms. Structural and defensive uses for calcareous skeletons are sometimes overrated.

  11. Butanol formation from gaseous substrates.

    Science.gov (United States)

    Dürre, Peter

    2016-03-01

    Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain. PMID:26903012

  12. DETERMINATION OF ACTIVATED SLUDGE MODEL ASDM PARAMETERS FOR WASTE WATER TREATMENT PLANT OPERATING IN THE SEQUENTIAL–FLOW TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Dariusz Zdebik

    2015-01-01

    Full Text Available This paper presents a method for calibration of activated sludge model with the use of computer program BioWin. Computer scheme has been developed on the basis of waste water treatment plant operating in the sequential – flow technology. For calibration of the activated sludge model data of influent and treated effluent from the existing object were used. As a result of conducted analysis was a change in biokinetic model and kinetic parameters parameters of wastewater treatment facilities. The presented method of study of the selected parameters impact on the activated sludge biokinetic model (including autotrophs maximum growth rate, the share of organic slurry in suspension general operational, efficiency secondary settling tanks can be used for conducting simulation studies of other treatment plants.

  13. Arsenic speciation in shrimp and mussel from the Mid-Atlantic hydrothermal vents

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Quetel, C. R.; Munoz, R.; FialaMedioni, A.; Donard, O. F. X.

    Specimens of shrimp (Rimicaris exoculata) and mussel (Bathymodiolus puteoserpentis) were collected 3500 m below the ocean surface at the hydrothermal vents of the mid-Atlantic Ridge (TAG and Snake Pit sites, respectively). Arsenic, a potentially toxic element, is among the substances emitted by the...... hydrothermal vents. The hydrothermal vent shrimp, which are known to be a primary consumer of the primary producing chemolithoautotrophic bacteria, contained arsenic at 13 mu g g(-1) almost exclusively as arsenobetaine (AsB). Arsenic was present in the soft:issues of the mussel at 40 mu g g(-1) and the major...... of arsenic species found in the shrimp and mussel species in the deep-sea is similar to that found in their counterparts from the ocean surface. It is concluded that the autotrophic bacteria of the hydrothermal vent ecosystem and the symbiotic bacteria harboured in the mussel species are responsible...

  14. Chlorophyll content and culture of flax embryos in vitro

    Directory of Open Access Journals (Sweden)

    A. Petrova

    2014-02-01

    Full Text Available During in vitro cultivation of green flax embryos excised 14 days after fertilization on White's medium the chloraphylls a and b are gradually destroyed and the lamellar system of plastids is disintegrated. It was possible, to prolong somewhat the presence of chlorophyll and to enhance embryo growth by culture in the dark and by adding kinetin. Light has a stimulating effect on the germination of embryos. Streptomycin inhibits chlorophyll synthesis not earlier than at germination. Young, green embryos are unable to sumvive and develop on media without sucrose. It is supposed that photosynthesis does not occur in flax embryos in vitro, and that green embryos are not more autotrophic in vitro than those of leucoembryophytes.

  15. Metabolism and Gaseous Exchanges in Two Coastal Lagoons from Rio de Janeiro with Distinct Limnological Characteristics

    Directory of Open Access Journals (Sweden)

    Thomaz Sidinei M.

    2001-01-01

    Full Text Available The global metabolism and exchange of gases with the atmosphere were measured during a diel cycle in two tropical coastal lagoons, using the curves of carbon dioxide and dissolved oxygen. Heterotrophic metabolism (net CO2 production and net O2 consumption was observed in a black water lagoon (Comprida, and autotrophic metabolism (net O2 production and net CO2 consumption in a clear water lagoon (Imboassica. These differences were attributed to the limnological characteristics of both ecosystems, especially to dissolved organic carbon and the attenuation coefficient of light, which are much higher in the first environment. During the diel cycle analyzed there was a net release of carbon dioxide into the atmosphere in the first lagoon and a net uptake by the water in the second one. Thus, the importance of coastal lagoons for the global carbon budget deserves further study.

  16. Activated sludge filterability improvement by nitrifying bacteria abundance regulation in an adsorption membrane bioreactor (Ad-MBR).

    Science.gov (United States)

    Sun, Fei-yun; Lv, Xiao-mei; Li, Ji; Peng, Zhong-yi; Li, Pu; Shao, Ming-fei

    2014-10-01

    Autotrophic nitrifying bacteria have its intrinsic properties including low EPS production, dense colonial structure and slow-growth rate, favoring the sludge filterability improvement. An adsorption-MBR (Ad-MBR) was developed to enrich nitrifier abundance in the MBR chamber by inlet C/N regulation, and its possible positive effect on sludge filterability and underlying mechanisms were investigated. By DNA extraction, PCR amplification and Illumina high-throughput pyrosequencing, the abundance of nitrifying bacteria was accurately quantified. More than 8.29% nitrifier abundance was achieved in Ad-MBR sludge, which was above three times of that in conventional MBR. Regulated C/N ratio and thereafter nitrifier abundance enrichment improved sludge filterability by altering sludge mixture and its supernatant properties, reflected by a good sludge settleability, a low supernatant viscosity and turbidity, a low supernatant organic substances concentration, and a small amount of strong hydrophobic fractional components, thus to profoundly improve sludge filterability and decelerate membrane fouling. PMID:25146315

  17. Enhanced Performance of Denitrifying Sulifde Removal Process by 1,2-Naphthoquinone-4-Sulphonate

    Institute of Scientific and Technical Information of China (English)

    Liu Chunshuang; Han Kang; Zhao Dongfeng; Guo Yadonag; Liu Lihong; Liu Fang; Zhao Chaocheng

    2016-01-01

    The denitrifying sulifde removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitriifers can simultaneously convert nitrate, sulifde and acetate species into di-nitrogen gas, elemental sulfur and carbon dioxide, respectively, at high loading rates. This study has determined that the reaction rate of sulifde oxidized into sulfur could be enhanced in the presence of 1,2-naphthoquinone-4-sulphonate (NQS). The presence of NQS mitigated the inhibi-tion effects of sulifde species on denitriifcation. Furthermore, the reaction rates of nitrate and acetate to nitrogen gas and CO2, respectively, were also promoted in the presence of NQS, thereby enhancing the performance of DSR granules. The advantages and disadvantages of applying the NQS-DSR process are discussed.

  18. Microbial community structure at the U.S.-Joint Global Ocean Flux Study Station ALOHA: Inverse methods for estimating biochemical indicator ratios

    Science.gov (United States)

    Christian, James R.; Karl, David M.

    1994-01-01

    Modeling biogeochemical fluxes in the marine plankton requires the application of factors for extrapolation of biomass indicators measured in the field (chlorophyll a, adenosine triphosphate, bacterial counts) to biomass carbon or nitrogen. These are often inferred from culture studies and are poorly constrained for natural populations. At least squares inverse method with a simple linear model constrains the values of several common indicator ratios, giving self-consistent solutions that provide useful information about the structure of the microbial community at our North Pacific Ocean study site (Station ALOHA (A Long-term Oligotrophic Habitat Assessment)). These results indicate that the fraction of the microbial biomass that is autotrophic (pigmented) is greater in the mixed layer than at the deep chlorophyll maximum layer and that heterotrophic bacteria are a significant but not necessarily predominant component of the microbial community in the euphotic zone.

  19. Microalgae as the Third Generation Biofuel:Production, Usage, Challenges and Prospects

    OpenAIRE

    Wang, Yue

    2013-01-01

    Microalgae refer to a kind of autotrophic microorganism with rich nutrition and high photosynthetic utilization degree, which are widely living in the sea and land. Microalgae can be converted into bio energy such as biogas, biodiesel and bio oil. This thesis presents a review on the different cultivation methods and energy conversion techniques of microalgae. Through comparison with other biomass feedstocks, the advantages and disadvantages of microalgae are detailed. Since the large scale o...

  20. Hotspots of anaerobic ammonia oxidation in land - freshwater interfaces

    DEFF Research Database (Denmark)

    Zhu, Guibing; Wang, Shanyun; Wang, Weidong;

    2013-01-01

    sampled fromlake riparian zones in North China. Laboratory incubations in the presence of ammonium or nitrate—at concentrations equivalent to no more than 10% of those detected in situ—yielded some of the highest potential anammox activities reported for natural environments to date. Potential rates of......For decades, the conversion of organic nitrogen to dinitrogen gas by heterotrophic bacteria, termed heterotrophic denitrification, was assumed to be the main pathway of nitrogen loss in natural ecosystems. Recently, however, autotrophic bacteria have been shown to oxidize ammonium in the absence of...... anammox peaked in sediments sampled from the interface between the land and the water, as did the abundance of annamox bacteria. Scaling our findings up to the entire lake system, we estimate that interfacial anammox hotspots account for the loss of 103 gNm-2 yr-1 from this lake region, and around one...

  1. Modeling and visual simulation of Microalgae photobioreactor

    Science.gov (United States)

    Zhao, Ming; Hou, Dapeng; Hu, Dawei

    Microalgae is a kind of nutritious and high photosynthetic efficiency autotrophic plant, which is widely distributed in the land and the sea. It can be extensively used in medicine, food, aerospace, biotechnology, environmental protection and other fields. Photobioreactor which is important equipment is mainly used to cultivate massive and high-density microalgae. In this paper, based on the mathematical model of microalgae which grew under different light intensity, three-dimensional visualization model was built and implemented in 3ds max, Virtools and some other three dimensional software. Microalgae is photosynthetic organism, it can efficiently produce oxygen and absorb carbon dioxide. The goal of the visual simulation is to display its change and impacting on oxygen and carbon dioxide intuitively. In this paper, different temperatures and light intensities were selected to control the photobioreactor, and dynamic change of microalgal biomass, Oxygen and carbon dioxide was observed with the aim of providing visualization support for microalgal and photobioreactor research.

  2. Biological removal of nitrogen from waste water

    Energy Technology Data Exchange (ETDEWEB)

    Dombrowski, T.; Lompe, D.; Wiesmann, U.

    1989-02-01

    The biological treatment of waste water with both a high organic (2500 mg/l DOC) and high ammonia concentration (600 mg/l NH/sub 4//sup +/-N) was investigated. The first step consists of a two step anaerobic cascade of fixed bed loop reactors with polyurethan foam particles as support material for bacterica. The aerobic treatment occurs in two aerated stirred tanks with sedimentation tanks and two separate sludge recycle systems each for heterotrophic and autotrophic biomass resulting in a degradation of organic compounds (first tank) and nitrification (second tank). Finally the nitrate is reduced by biological denitrification. By optimization the total hydraulic retention time could be reduced to 7 hr. Nitrification is the most sensitive step and can be on-line controlled by measurement of oxygen consumption.

  3. Investigating Nitrosomonas europaea stress biomarkers in batch, continuous culture, and biofilm reactors.

    Science.gov (United States)

    Radniecki, Tyler S; Lauchnor, Ellen G

    2011-01-01

    The understanding of nitrification inhibition in ammonia oxidizing bacteria (AOB) by priority pollutants and emerging contaminants is critical in managing the nitrogen cycle to preserve current water supplies, one of the National Academy of Engineers Grand Challenges in Engineering for the twenty-first century. Nitrosomonas europaea is an excellent model AOB for nitrification inhibition experimentation due to its well-defined NH(3) metabolism and the availability of a wide range of physiological and transcriptional tools that can characterize the mechanism of nitrification inhibition and probe N. europaea's response to the inhibitor. This chapter is a compilation of the physiological and transcriptional methods that have been used to characterize nitrification inhibition of N. europaea under a wide variety of growth conditions including batch, continuously cultured, and in biofilms. The protocols presented here can be applied to other AOB, and may be readily adapted for other autotrophic bacteria (e.g., nitrite oxidizing bacteria). PMID:21514466

  4. Profiling of lipid and glycogen accumulations under different growth conditions in the sulfothermophilic red alga Galdieria sulphuraria.

    Science.gov (United States)

    Sakurai, Toshihiro; Aoki, Motohide; Ju, Xiaohui; Ueda, Tatsuya; Nakamura, Yasunori; Fujiwara, Shoko; Umemura, Tomonari; Tsuzuki, Mikio; Minoda, Ayumi

    2016-01-01

    The unicellular red alga Galdieria sulphuraria grows efficiently and produces a large amount of biomass in acidic conditions at high temperatures. It has great potential to produce biofuels and other beneficial compounds without becoming contaminated with other organisms. In G. sulphuraria, biomass measurements and glycogen and lipid analyses demonstrated that the amounts and compositions of glycogen and lipids differed when cells were grown under autotrophic, mixotrophic, and heterotrophic conditions. Maximum biomass production was obtained in the mixotrophic culture. High amounts of glycogen were obtained in the mixotrophic cultures, while the amounts of neutral lipids were similar between mixotrophic and heterotrophic cultures. The amounts of neutral lipids were highest in red algae, including thermophiles. Glycogen structure and fatty acids compositions largely depended on the growth conditions. PMID:26595665

  5. Influence of waste water from oil refinery on species and biomass of microzoon in rootzone of water hyacinth

    International Nuclear Information System (INIS)

    There are lots of biological species in rootzone of water hyacinth, which can purify waste water from oil refinery. Rootzone of water hyacinth is an ecological subsystem. There are 20 microzoon species including 13 protozoa, 3 rotifer and 4 others. The main species are Vorticella convallaria, Rotaria rotatoria and Lepadella patella with percentages of 18.5%, 17.5% and 34.5%, respectively. The longer retention time of the waste water is in the oxidation pond, the more species and the bigger population of microzoon in rootzone of water hyacinth. The total biomass increases along with waste water flow. The maximum value of the population is 1.91 x 107 ind/m2. There is no microzoon except Englena which is an autotrophic organism in control pond. Increase of retention time of waste water is beneficial to biomass of microzoon and has no effect on the content of aerobic and facultative aerobic microbes in oxidation pond

  6. Microbial community structure at the U.S. -Joint Global Ocean flux Study Station ALOHA: Inverse methods for estimating biochemical indicator ratios

    Science.gov (United States)

    Christian, James R.; Karl, David M.

    1994-07-01

    Modeling biogeochemical fluxes in the marine plankton requires the application of factors for extrapolation of biomass indicators measured in the field (chlorophyll a, adenosine triphosphate, bacterial counts) to biomass carbon or nitrogen. These are often inferred from culture studies and are poorly constrained for natural populations. A least squares inverse method with a simple linear model constrains the values of several common indicator ratios, giving self-consistent solutions that provide useful information about the structure of the microbial community at our North Pacific Ocean study site (Station ALOHA (A Long-term Oligotrophic Habitat Assessment)). These results indicate that the fraction of the microbial biomass that is autotrophic (pigmented) is greater in the mixed layer than at the deep chlorophyll maximum layer and that heterotrophic bacteria are a significant but not necessarily predominant component of the microbial community in the euphotic zone.

  7. Coupling auto trophic in vitro plant cultivation system to scanning electron microscope to study plant-fungal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, N. de; Decock, C.; Declereck, S.; Providencia, I. E. de la

    2010-07-01

    The interactions of plants with pathogens and beneficial micro-organisms have been seldom compared on the same host and under strict controlled auto trophic in vitro culture conditions. Here, the life cycle of two plant beneficial (Glomus sp. MUCL 41833 and Trichoderma harzianum) and one plant pathogen (Rhizoctonia solani) fungi were described on potato (Solanum tuberosum) plantlets under auto trophic in vitro culture conditions using video camera imaging and the scanning electron microscope (SEM). (i) The colony developmental pattern of the extraradical mycelium within the substrate, (ii) the reproduction structures and (iii) the three-dimensional spatial arrangements of the fungal hyphae within the potato root cells were successfully visualized, monitored and described. The combination of the autotrophic in vitro culture system and SEM represent a powerful tool for improving our knowledge on the dynamics of plant-fungal interactions. (Author) 41 refs.

  8. Seasonal rates of benthic primary production in a Greenland fjord measured by aquatic eddy correlation

    DEFF Research Database (Denmark)

    M. Attard, Karl; Glud, Ronnie; McGinnis, Daniel F.;

    2014-01-01

    We present the first year-round estimates of benthic primary production at four contrasting shallow (3–22 m depth) benthic habitats in a southwest Greenland fjord. In situ measurements were performed using the noninvasive aquatic eddy-correlation (EC) oxygen (O2) flux method. A series of high-qua...... document the importance of benthic photosynthesis on an ecosystem level and indicate that the benthic phototrophic compartment should be accounted for when assessing carbon and nutrient budgets as well as responses of coastal Arctic ecosystems to climate change.......-quality multiple-day EC data sets document the presence of a year-round productive benthic phototrophic community. The shallow-water sites were on average autotrophic during the spring and summer months, up to 43.6 mmol O2 m22 d21, and heterotrophic or close to metabolic balance during the autumn and winter...

  9. Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain).

    Science.gov (United States)

    Sánchez-Rodríguez, Alvaro; Sosa-Ferrera, Zoraida; Santana-del Pino, Angelo; Santana-Rodríguez, José Juan

    2011-05-01

    The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%. PMID:21396664

  10. SEASONAL DYNAMIC AND DRIVE MECHANISM OF SOIL RESPIRATION IN THREE TEMPERATE FORESTS%3种温带森林土壤呼吸季节动态及其驱动机制

    Institute of Scientific and Technical Information of China (English)

    张俊兴; 苏宏新; 刘海丰; 高润宏

    2011-01-01

    本研究通过壕沟法定量区分自养呼吸和异养呼吸,结合各种监测因子初步探讨北京东灵山地区3种温带森林土壤呼吸季节变化及其驱动机制.结果表明:3种森林生态系统的土壤呼吸、异氧呼吸和自养呼吸呼吸速率均呈现明显的季节变化;异养呼吸在土壤呼吸中占较大比重,辽东栎林、华北落叶松林、油松林土壤异养呼吸分别占总呼吸的80%、71%、77%,在3种林型之间的差异达到极显著水平(P<0.001).土壤温度是影响土壤呼吸各组分的主要环境因子,影响土壤呼吸的生物因子在不同林型间存在差异,细根净输入量很大程度上决定了自养呼吸的总量,凋落物净输入量对于异养呼吸有重要影响.%Based upon the field data on seasonal dynamic of soil respiration in three temperate forests, we could obtain the response of soil respiration, autotrophic respiration and heterotrophic respiration to the soil temperature, soil water moisture, leaf area index, fine root biomass, fine root turnover and litter turnover in Donglinshan mountain. The relationship proposed for soil respiration with these factors was useful for understanding and predicting potential changes in Beijing Donglinshan mountain forest ecosystem in response to forest management and climate change. We used trench method to sepetate components of soil respiration in three typical forestlands. A study was conducted to determine the seasonal dynamic of soil respiration and the drive mechanism of the changes in temperate forests in Donglingshan mountain from April to October in 2010. Results indicated that the total soil respiration, heterotrophic respiration and autotrophic respiration of three temperate forests followed a similar seasonal trend, and heterotrophic respiration differences in forest types ( P < 0.001) . The contributions of heterotrophic respiration to the total soil respiration of Oak forest, Larch forest and Pine forest were 80%

  11. Niche specialization and functional traits regulate the rarity of charophytes in the Nordic countries

    DEFF Research Database (Denmark)

    Båstrup-Spohr, Lars; Iversen, Lars Lønsman; Borum, Jens;

    2015-01-01

    , while specialists often have short stature, restricted life cycle variability and are rare in the disturbed contemporary landscape. It is thus a conservation priority to delineate accurately the environmental conditions preferred by the threatened species and protect or restore proper habitats.......1. Charophytes are benthic macroalgae that live in fresh and brackish waters. Given the historic deterioration of their habitats and their competitive inferiority relative to tall rooted plants under eutrophic conditions, it is hypothesized that charophytes are among the most threatened autotrophs....... Also, it is expected that charophytes with generalist niches and functional traits, such as tolerance of a broad salinity range and large height, should thrive owing to available habitats and stronger competitive ability. 2. These hypotheses were tested comparing the rarity of charophytes in the Nordic...

  12. Hydrogen production employing Spirulina maxima 2342: A chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Juantorena, A.U.; Santoyo, E.; Gamboa, S.A.; Lastres, O.D. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Sebastian, P.J. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Cuerpo Academico de Energia, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Sanchez-Escamilla, D. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Bustos, A. [Centro de Ciencias Fisicas, UNAM, Ave. Universidad, Cuernavaca, Morelos (Mexico); Eapen, D. [Investigacion y Desarrollo en Agroindustria, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    The biomass of the cyanobacteria, Spirulina maxima 2342, was autotrophically obtained in a 20 l bioreactor under illumination and air bubbling and analyzed for its photobiological hydrogen production capability. A volume of 250 ml of Spirulina sp. taken from the reactor was used as culture sample for performing the experiments. An illumination-agitation process was employed to induce the hydrogen photoproduction reaction. The hydrogen produced in this process was quantified by gas chromatography technique using Molesieve 5 A(16ft x (1)/(8)in) column and a thermal conductivity detector (with a detector temperature of 110{sup o}C and a column temperature of 60{sup o}C). The culture samples were finally observed in an electron microscope to evaluate the effect of vacuum on the Spirulina sp. cells. (author)

  13. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    International Nuclear Information System (INIS)

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S0), N2, and CO2, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

  14. Combined autoradiography and immunofluorescence for estimation of single cell activity by ammonium-oxidizing bacteria

    International Nuclear Information System (INIS)

    Immunofluorescence and 14CO2 autoradiography were used for simultaneously enumerating and assaying the autotrophic activity of ammonium-oxidizing bacteria in seawater. Relative activity (14CO2 assimilation as measured by autoradiography) and abundance were measured in simulated in situ incubations at seven stations in the primary NO2- maximum region of the Northeast Pacific Ocean. More than 104 cells-liter-1 were present; relative activity often showed a peak near the surface and an increase in the NO2- max region below the photic zone. The method permits assessment of individual cell activity; most cells at all depths were active in CO2 assimilation, usually at low and quite variable levels. Relative activity was positively correlated with the abundance of ammonium-oxidizing bacteria, temperature, total dark CO2 assimilation and phenopigment concentration

  15. Multiphyletic origins of methylotrophy in Alphaproteobacteria, exemplified by comparative genomics of Lake Washington isolates.

    Science.gov (United States)

    Beck, David A C; McTaggart, Tami L; Setboonsarng, Usanisa; Vorobev, Alexey; Goodwin, Lynne; Shapiro, Nicole; Woyke, Tanja; Kalyuzhnaya, Marina G; Lidstrom, Mary E; Chistoserdova, Ludmila

    2015-03-01

    We sequenced the genomes of 19 methylotrophic isolates from Lake Washington, which belong to nine genera within eight families of the Alphaproteobacteria, two of the families being the newly proposed families. Comparative genomic analysis with a focus on methylotrophy metabolism classifies these strains into heterotrophic and obligately or facultatively autotrophic methylotrophs. The most persistent metabolic modules enabling methylotrophy within this group are the N-methylglutamate pathway, the two types of methanol dehydrogenase (MxaFI and XoxF), the tetrahydromethanopterin pathway for formaldehyde oxidation, the serine cycle and the ethylmalonyl-CoA pathway. At the same time, a great potential for metabolic flexibility within this group is uncovered, with different combinations of these modules present. Phylogenetic analysis of key methylotrophy functions reveals that the serine cycle must have evolved independently in at least four lineages of Alphaproteobacteria and that all methylotrophy modules seem to be prone to lateral transfers as well as deletions. PMID:25683159

  16. Hydrogen production by photosynthetic water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E.; Lee, J.W.; Tevault, C.V. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Contrary to the prediction of the {open_quotes}Z-scheme{close_quotes} model of photosynthesis, experiments demonstrated that mutants of Chlamydomonas containing Photosystem II (PSII) but lacking Photosystem I (PSI), can grow photoautotrophically with O{sub 2} evolution and using atmospheric CO{sub 2} as the sole carbon source. Autotrophic photosynthesis by PSI-deficient mutants was stable both under anaerobic conditions and in air (21% O{sub 2}) at an actinic intensity of 200 {mu}E/m{sup -2}{sup {sm_bullet}}s. This {open_quotes}PSII photosynthesis,{close_quotes} sufficient to support cell development and mobility, may also occur in wild-type green algae and higher plants. The mutants can survive under 2000 {mu}E{sup {sm_bullet}}m{sup -2}{sup {sm_bullet}}s{sup -1} with air, although they have less resistance to photoinhibition.

  17. Nutrient flows between ecosystems can destabilize simple food chains.

    Science.gov (United States)

    Marleau, Justin N; Guichard, Frédéric; Mallard, François; Loreau, Michel

    2010-09-01

    Dispersal of organisms has large effects on the dynamics and stability of populations and communities. However, current metacommunity theory largely ignores how the flows of limiting nutrients across ecosystems can influence communities. We studied a meta-ecosystem model where two autotroph-consumer communities are spatially coupled through the diffusion of the limiting nutrient. We analyzed regional and local stability, as well as spatial and temporal synchrony to elucidate the impacts of nutrient recycling and diffusion on trophic dynamics. We show that nutrient diffusion is capable of inducing asynchronous local destabilization of biotic compartments through a diffusion-induced spatiotemporal bifurcation. Nutrient recycling interacts with nutrient diffusion and influences the susceptibility of the meta-ecosystem to diffusion-induced instabilities. This interaction between nutrient recycling and transport is further shown to depend on ecosystem enrichment. It more generally emphasizes the importance of meta-ecosystem theory for predicting species persistence and distribution in managed ecosystems. PMID:20600133

  18. Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Ma, Wenjuan; Guo, Yadong; Wang, Aijie; Wang, Qilin; Lee, Duu-Jong

    2016-02-01

    Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S(0)), carbon dioxide, and nitrogen-containing gas (such as N2) at NaCl concentration of 35-70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S(0) conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity. PMID:26454867

  19. Biocathodes reducing oxygen at high potential select biofilms dominated by Ectothiorhodospiraceae populations harboring a specific association of genes.

    Science.gov (United States)

    Desmond-Le Quéméner, Elie; Rimboud, Mickaël; Bridier, Arnaud; Madigou, Céline; Erable, Benjamin; Bergel, Alain; Bouchez, Théodore

    2016-08-01

    Biocathodes polarized at high potential are promising for enhancing Microbial Fuel Cell performances but the microbes and genes involved remain poorly documented. Here, two sets of five oxygen-reducing biocathodes were formed at two potentials (-0.4V and +0.1V vs. saturated calomel electrode) and analyzed combining electrochemical and metagenomic approaches. Slower start-up but higher current densities were observed at high potential and a distinctive peak increasing over time was recorded on cyclic voltamogramms, suggesting the growth of oxygen reducing microbes. 16S pyrotag sequencing showed the enrichment of two operational taxonomic units (OTUs) affiliated to Ectothiorodospiraceae on high potential electrodes with the best performances. Shotgun metagenome sequencing and a newly developed method for the identification of Taxon Specific Gene Annotations (TSGA) revealed Ectothiorhodospiraceae specific genes possibly involved in electron transfer and in autotrophic growth. These results give interesting insights into the genetic features underlying the selection of efficient oxygen reducing microbes on biocathodes. PMID:27126080

  20. Natural Pyrrhotite as a Catalyst in Prebiotic Chemical Evolution

    Directory of Open Access Journals (Sweden)

    César Menor-Salván

    2013-08-01

    Full Text Available The idea of an autotrophic organism as the first living being on Earth leads to the hypothesis of a protometabolic, complex chemical system. In one of the main hypotheses, the first metabolic systems emerged from the interaction between sulfide minerals and/or soluble iron-sulfide complexes and fluids rich in inorganic precursors, which are reduced and derived from crustal or mantle activity. Within this context, the possible catalytic role of pyrrhotite, one of the most abundant sulfide minerals, in biomimetic redox and carbon fixation reactions was studied. Our results showed that pyrrhotite, under simulated hydrothermal conditions, could catalyze the pyruvate synthesis from lactate and that a dynamic system formed by coupling iron metal and iron-sulfur species in an electrochemical cell could promote carbon fixation from thioacetate esters.