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Sample records for autotrophic nitrifying bioreactor

  1. 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

    Addition of hydroxylamine (NH2OH) to autotrophic biomass in nitrifying bioreactors affected the activity, physical structure, and microbial ecology of nitrifying aggregates. When NH2OH is added to nitrifying cultures in 6-h batch experiments, the initial NH3-N uptake rates were physiologically...... accelerated by a factor of 1.4-13. NH2OH addition caused a 20-40% decrease in the median aggregate size, broadened the shape of the aggregate size distribution by up to 230%, and caused some of the microcolonies to appear slightly more dispersed. Longer term NH2OH addition in fed batch bioreactors decreased...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. Modeling bioaugmentation with nitrifiers in membrane bioreactors.

    Science.gov (United States)

    Mannucci, Alberto; Munz, Giulio; Mori, Gualtiero; Makinia, Jacek; Lubello, Claudio; Oleszkiewicz, Jan A

    2015-01-01

    Bioaugmentation with nitrifiers was studied using two pilot-scale membrane bioreactors, with the purpose of assessing the suitability of state-of-the-art activated sludge models (ASMs) in predicting the efficiency of bioaugmentation as a function of operating conditions. It was demonstrated that the temperature difference between seeding and seeded reactors (ΔT) affects bioaugmentation efficiency. Experimental data were accurately predicted when ΔT was within a range of up to 10 °C at the higher range, and when the temperature was significantly lower in the seeded reactor compared to the seeding one, standard ASMs overestimated the efficiency of bioaugmentation. A modified ASM, capable of accurately representing the behavior of seeded nitrifying biomass in the presence of high ΔT, would require the inclusion of the effect of temperature time gradients on nitrifiers. A simple linear correlation between ΔT and the Arrhenius coefficient was proposed as a preliminary step.

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

    NARCIS (Netherlands)

    Veuger, B.; 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 inc

  8. Cell adhesion, ammonia removal and granulation of autotrophic nitrifying sludge facilitated by N-acyl-homoserine lactones.

    Science.gov (United States)

    Li, An-Jie; Hou, Bao-Lian; Li, Mei-Xi

    2015-11-01

    In this study, six N-acyl-homoserine lactone (AHL) molecules (C6-HSL, C8-HSL, C10-HSL, 3-oxo-C6-HSL, 3-oxo-C8-HSL and 3-oxo-C10-HSL) were each dosed into a bioreactor and seeded using autotrophic nitrifying sludge (ANS). The effects of the AHLs on cell adhesion, nitrification and sludge granulation were investigated. The results indicated that the efficiencies of cell adhesion and ammonia removal both had a close correlation with the side chain length and β position substituent group of the AHLs. The best-performing AHL in terms of accelerating bacterial attached-growth was 3-oxo-C6-HSL, whereas C6-HSL outperformed the others in terms of the ammonia degradation rate. The addition of 3-oxo-C6-HSL or C6-HSL increased the biomass growth rate, microbial activity, extracellular proteins and nitrifying bacteria, which can accelerate the formation of nitrifying granules. Consequently, selecting AHL molecules that could improve bacteria in attached-growth mode and nitrification efficiency simultaneously will most likely facilitate the rapid granulation of nitrifying sludge.

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

    Science.gov (United States)

    Veuger, Bart; Pitcher, Angela; Schouten, Stefan; Sinninghe Damsté, Jaap S.; Middelburg, Jack J.

    2013-04-01

    A dual stable isotope (15N and 13C) tracer approach in combination with compound-specific stable isotope analysis of bacterial and Thaumarchaeotal lipid biomarkers was used to investigate nitrification and the associated growth of autotrophic nitrifiers in the Dutch coastal North Sea. This study focusses on the stoichiometry between nitrification and DIC fixation by autotrophic nitrifiers as well as on the contributions of bacteria versus Thaumarchaeota to total autotrophic DIC-fixation by nitrifiers. Water from the dutch coastal North Sea was collected at weekly to biweekly intervals during the winter of 2007-2008. Watersamples were incubated with 15N-labeled ammonium and 15N was traced into nitrate and suspended material to quantify rates of nitrification and ammonium assimilation respectively. Growth of autotrophic nitrifiers was measured by incubating water samples with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) and subsequent analysis of 13C in bacterial phospholipid-derived fatty acids (PLFAs) and the Thaumarchaeotal biomarker crenarchaeol. Results revealed high nitrification rates with nitrification being the primary sink for ammonium. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27-95%). The ratio between rates of nitrification versus DIC fixation by nitrifiers was higher or even much higher than typical values for autotrophic nitrifiers, indicating that little DIC was fixed relative to the amount of energy that was generated by nitrification, and hence that other other processes for C acquisition may have been relevant as well. 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

  10. 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

  11. 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

  12. 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

  13. Start-up of anaerobic ammonia oxidation bioreactor with nitrifying activated sludge

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ping; LIN Feng-mei; HU Bao-lan; CHEN Jian-song

    2004-01-01

    The anaerobic ammonia oxidation(Anammox) bioreactor was successfully started up with the nitrifying activated sludge. After anaerobically operated for 105 d, the bioreactor reached a good performance with removal percentage of both ammonia and nitrite higher high efficiency and stability because it held a large amount of biomass in the bioreactor.

  14. A robust nitrifying community in a bioreactor at 50 °C opens up the path for thermophilic nitrogen removal.

    Science.gov (United States)

    Courtens, Emilie Np; Spieck, Eva; Vilchez-Vargas, Ramiro; Bodé, Samuel; Boeckx, Pascal; Schouten, Stefan; Jauregui, Ruy; Pieper, Dietmar H; Vlaeminck, Siegfried E; Boon, Nico

    2016-09-01

    The increasing production of nitrogen-containing fertilizers is crucial to meet the global food demand, yet high losses of reactive nitrogen associated with the food production/consumption chain progressively deteriorate the natural environment. Currently, mesophilic nitrogen-removing microbes eliminate nitrogen from wastewaters. Although thermophilic nitrifiers have been separately enriched from natural environments, no bioreactors are described that couple these processes for the treatment of nitrogen in hot wastewaters. Samples from composting facilities were used as inoculum for the batch-wise enrichment of thermophilic nitrifiers (350 days). Subsequently, the enrichments were transferred to a bioreactor to obtain a stable, high-rate nitrifying process (560 days). The community contained up to 17% ammonia-oxidizing archaea (AOAs) closely related to 'Candidatus Nitrososphaera gargensis', and 25% nitrite-oxidizing bacteria (NOBs) related to Nitrospira calida. Incorporation of (13)C-derived bicarbonate into the respective characteristic membrane lipids during nitrification supported their activity as autotrophs. Specific activities up to 198±10 and 894±81 mg N g(-1) VSS per day for AOAs and NOBs were measured, where NOBs were 33% more sensitive to free ammonia. The NOBs were extremely sensitive to free nitrous acid, whereas the AOAs could only be inhibited by high nitrite concentrations, independent of the free nitrous acid concentration. The observed difference in product/substrate inhibition could facilitate the development of NOB inhibition strategies to achieve more cost-effective processes such as deammonification. This study describes the enrichment of autotrophic thermophilic nitrifiers from a nutrient-rich environment and the successful operation of a thermophilic nitrifying bioreactor for the first time, facilitating opportunities for thermophilic nitrogen removal biotechnology. PMID:26894446

  15. 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

  16. Polymeric supports for the adhesion of a consortium of autotrophic nitrifying bacteria

    OpenAIRE

    Sousa, M; Azeredo, Joana; Feijó, J.; Oliveira, Rosário

    1997-01-01

    The nitrifying performance of the biofilm formed onto polymeric supports (high density polystyrene, polyethylene, polypropylene, polyvinylchloride and polymethyl-methacrylate) was correlated with hydrophobicity and surface charge of both bacteria and support media. Polypropylene, the most hydrophobic material, had the best properties for biofilm formation. The adhesion of nitrifying bacteria mainly governed by hydrophobic interactions though electrostatic interactions were a determinant when ...

  17. 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).

  18. 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

    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. Fluoresce......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....... Fluorescence in situ hybridization revealed that ammonia-oxidizing bacteria dominated within the first 200 mu m below the granule surface, nitrite-oxidizing bacteria a deeper layer between 200 and 300 mu m, while heterotrophic bacteria were present in the core of the nitrifying granule. Presence...... of these 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...

  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. Nitrifying Community Analysis in a Single Submerged Attached-Growth Bioreactor for Treatment of High-Ammonia Waste Stream

    DEFF Research Database (Denmark)

    Gu, April Z.; Pedros, Philip B; Kristiansen, Anja;

    2007-01-01

    This study investigated the nitrifying community structure in a single-stage submerged attached-growth bioreactor (SAGB) that successfully achieved stable nitrogen removal over nitrite of a high-strength ammonia wastewater. The reactor was operated with intermittent aeration and external carbon a...... in this study is applicable for high-ammonia-strength wastewater treatment, such as centrate or industrial wastes. Udgivelsesdato: December 2007...

  1. 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.

  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. Selective isolation of ammonia-oxidizing bacteria from autotrophic nitrifying granules by applying cell-sorting and sub-culturing of microcolonies

    Directory of Open Access Journals (Sweden)

    Hirotsugu eFujitani

    2015-10-01

    Full Text Available Nitrification is a key process in the biogeochemical nitrogen cycle and biological wastewater treatment that consists of two stepwise reactions, ammonia oxidation by ammonia-oxidizing bacteria (AOB or archaea followed by nitrite oxidation by nitrite-oxidizing bacteria. One of the representative of the AOB group is Nitrosomonas mobilis species. Although a few pure strains of this species have been isolated so far, approaches to their preservation in pure culture have not been established. Here, we report isolation of novel members of the N. mobilis species from autotrophic nitrifying granules used for ammonia-rich wastewater treatment. We developed an isolation method focusing on microcolonies formation of nitrifying bacteria. Two kinds of distinctive light scattering signatures in a cell-sorting system enabled to separate microcolonies from single cells and heterogeneous aggregates within granule samples. Inoculation of a pure microcolony into 96-well microtiter plates led to successful sub-culturing and increased probability of isolation. Obtained strain Ms1 is cultivated in the liquid culture with relatively high ammonia or nitrite concentration, not extremely slow growing. Considering environmental clones that were closely related to N. mobilis and detected in various environments, the availability of this novel strain would facilitate to reveal this member’s ecophysiology in a variety of habitats.

  4. Selective isolation of ammonia-oxidizing bacteria from autotrophic nitrifying granules by applying cell-sorting and sub-culturing of microcolonies.

    Science.gov (United States)

    Fujitani, Hirotsugu; Kumagai, Asami; Ushiki, Norisuke; Momiuchi, Kengo; Tsuneda, Satoshi

    2015-01-01

    Nitrification is a key process in the biogeochemical nitrogen cycle and biological wastewater treatment that consists of two stepwise reactions, ammonia oxidation by ammonia-oxidizing bacteria (AOB) or archaea followed by nitrite oxidation by nitrite-oxidizing bacteria. One of the representatives of the AOB group is Nitrosomonas mobilis species. Although a few pure strains of this species have been isolated so far, approaches to their preservation in pure culture have not been established. Here, we report isolation of novel members of the N. mobilis species from autotrophic nitrifying granules used for ammonia-rich wastewater treatment. We developed an isolation method focusing on microcolonies formation of nitrifying bacteria. Two kinds of distinctive light scattering signatures in a cell-sorting system enabled to separate microcolonies from single cells and heterogeneous aggregates within granule samples. Inoculation of a pure microcolony into 96-well microtiter plates led to successful sub-culturing and increased probability of isolation. Obtained strain Ms1 is cultivated in the liquid culture with relatively high ammonia or nitrite concentration, not extremely slow growing. Considering environmental clones that were closely related to N. mobilis and detected in various environments, the availability of this novel strain would facilitate to reveal this member's ecophysiology in a variety of habitats. PMID:26528282

  5. Isolation and characterization of heterotrophic nitrifying bacteria in MBR

    Institute of Scientific and Technical Information of China (English)

    LIN Yan; HE Yi-liang; KONG Hai-nan; LIU Bin-bin; LI Yan; INAMON Yuhei

    2005-01-01

    The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification.Continuous tests via a membrane bioreactor (MBR) were operated under the controlled conditions to proliferate the nitrifiers. Heterotrophic nitrifying bacteria were isolated from the system in which the efficiency of total nitrogen(TN) removal was up to 80%. Since no autotrophic ammonium and nitrite oxidizers could be detected by fluorescence in situ hybridization(FISH), oxidized-N production was unlikely to be catalyzed by autotrophic nitrifiers during the heterotrophic nitrifiers' isolation in this study. The batch test results indicate that the isolated heterotrophic bacteria were able to nitrify. After 3 weeks incubation, the efficiencies of the COD removal by the three isolated bacterial strains B1, B2, and B3 were 52.6%, 71.7%, and 77.7%, respectively. The efficiencies of the TN removal by B1, B2, and B3 were 35.6%, 61.2% and 68.7%, respectively.

  6. 454-Pyrosequencing Analysis of Bacterial Communities from Autotrophic Nitrogen Removal Bioreactors Utilizing Universal Primers: Effect of Annealing Temperature

    Directory of Open Access Journals (Sweden)

    Alejandro Gonzalez-Martinez

    2015-01-01

    Full Text Available Identification of anaerobic ammonium oxidizing (anammox bacteria by molecular tools aimed at the evaluation of bacterial diversity in autotrophic nitrogen removal systems is limited by the difficulty to design universal primers for the Bacteria domain able to amplify the anammox 16S rRNA genes. A metagenomic analysis (pyrosequencing of total bacterial diversity including anammox population in five autotrophic nitrogen removal technologies, two bench-scale models (MBR and Low Temperature CANON and three full-scale bioreactors (anammox, CANON, and DEMON, was successfully carried out by optimization of primer selection and PCR conditions (annealing temperature. The universal primer 530F was identified as the best candidate for total bacteria and anammox bacteria diversity coverage. Salt-adjusted optimum annealing temperature of primer 530F was calculated (47°C and hence a range of annealing temperatures of 44–49°C was tested. Pyrosequencing data showed that annealing temperature of 45°C yielded the best results in terms of species richness and diversity for all bioreactors analyzed.

  7. Nitrification performance and microbial ecology of nitrifying bacteria in a full-scale membrane bioreactor treating TFT-LCD wastewater.

    Science.gov (United States)

    Whang, Liang-Ming; Wu, Yi-Ju; Lee, Ya-Chin; Chen, Hong-Wei; Fukushima, Toshikazu; Chang, Ming-Yu; Cheng, Sheng-Shung; Hsu, Shu-Fu; Chang, Cheng-Huey; Shen, Wason; Huang, Chung Kai; Fu, Ryan; Chang, Barkley

    2012-10-01

    This study investigated nitrification performance and nitrifying community in one full-scale membrane bioreactor (MBR) treating TFT-LCD wastewater. For the A/O MBR system treating monoethanolamine (MEA) and dimethyl sulfoxide (DMSO), no nitrification was observed, due presumably to high organic loading, high colloidal COD, low DO, and low hydraulic retention time (HRT) conditions. By including additional A/O or O/A tanks, the A/O/A/O MBR and the O/A/O MBR were able to perform successful nitrification. The real-time PCR results for quantification of nitrifying populations showed a high correlation to nitrification performance, and can be a good indicator of stable nitrification. Terminal restriction fragment length polymorphism (T-RFLP) results of functional gene, amoA, suggest that Nitrosomonas oligotropha-like AOB seemed to be important to a good nitrification in the MBR system. In the MBR system, Nitrobacter- and Nitrospira-like NOB were both abundant, but the low nitrite environment is likely to promote the growth of Nitrospira-like NOB.

  8. Nitrous oxides reduction pathways induced during nitrified leachate recirculation in bioreactor landfill; Voies de reduction des oxydes d'azote lors de leur injection dans un massif de dechets menagers et assimiles: contribution a l'etude de la recirculation de lixiviat nitrifie dans une installation de stockage de dechets menagers et assimiles bioactive

    Energy Technology Data Exchange (ETDEWEB)

    Vigneron, V.

    2005-12-15

    Nitrified leachate recirculation in bioreactor landfill has been proposed to avoid ammonium accumulation. We worked on the identification of nitrous oxides reduction pathways induced when nitrified leachate is recirculated during waste degradation. Batch reactors (1.1 liter, 40 g of reconstituted Municipal Solid Waste, MSW) were operated at 35 deg C and saturated with leachate. Injections of 250 mg N-NO{sub x}.10{sup -1} were performed during different phases of waste biodegradation. Nitrate reduction during acido-genic and active methanogenic phases, with an easily available carbon source in leachate, was mainly attributed to heterotrophic denitrification. However, H{sub 2}S concentration up to 0.7 % in the biogas (corresponding to 0.5 mmol of free H{sub 2}S per liter of leachate) led to prevalent DNRA (Dissimilatory Nitrate Reduction to Ammonium) over denitrification. This reaction hindered the release of nitrogen outside of the system. This observation was confirmed with experiments performed with {sup 15}N enriched nitrate. During late methanogenic phase, without any available carbon source in leachate, nitrate was reduced by autotrophic denitrification with sulfide as an electron donor. No free metal was detected in the leachate. N{sub 2}O transient accumulation was detected during both DNRA and autotrophic denitrification. A second set of experiments was conducted in a MSW pilot scale column (0.2 m{sup 3}, 80 kg of reconstituted waste) in methanogenic phase. 113 % and 203 % of nitrate were converted into N{sub 2} when a synthetic KNO{sub 3} solution (280 mg N.day{sup -1} during 77 days) or nitrified leachate (61 mg N.day{sup -1} during 54 days) were respectively injected into the system. The downward movement of a denitrification front passing through the waste mass was followed using 3 redox probes inserted at different levels of the pilot. Even if N{sub 2}O was never detected, a small production of this gas could not be totally excluded. It was established

  9. A preliminary and qualitative study of resource ratio theory to nitrifying lab-scale bioreactors.

    Science.gov (United States)

    Bellucci, Micol; Ofiţeru, Irina D; Beneduce, Luciano; Graham, David W; Head, Ian M; Curtis, Thomas P

    2015-05-01

    The incorporation of microbial diversity in design would ideally require predictive theory that would relate operational parameters to the numbers and distribution of taxa. Resource ratio-theory (RRT) might be one such theory. Based on Monod kinetics, it explains diversity in function of resource-ratio and richness. However, to be usable in biological engineered system, the growth parameters of all the bacteria under consideration and the resource supply and diffusion parameters for all the relevant nutrients should be determined. This is challenging, but plausible, at least for low diversity groups with simple resource requirements like the ammonia oxidizing bacteria (AOB). One of the major successes of RRT was its ability to explain the 'paradox of enrichment' which states that diversity first increases and then decreases with resource richness. Here, we demonstrate that this pattern can be seen in lab-scale-activated sludge reactors and parallel simulations that incorporate the principles of RRT in a floc-based system. High and low ammonia and oxygen were supplied to continuous flow bioreactors with resource conditions correlating with the composition and diversity of resident AOB communities based on AOB 16S rDNA clone libraries. Neither the experimental work nor the simulations are definitive proof for the application of RRT in this context. However, it is sufficient evidence that such approach might work and justify a more rigorous investigation.

  10. Isolation and Characterization of a New Heterotrophic Nitrifying Bacillus sp. Strain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To characterize the heterotrophic nitrifying bacteria. Methods The bacteria were isolated from membrane bioreactor for treating synthetic wastewater using the method newly introduced in this study. Fluorescence in situ hybridization (FISH) was used to validate the nonexistence of autotrophic ammonia oxidizers and nitrite oxidizers. Batch tests were carried out to investigate the capability of heterotrophic nitrification by the pure culture. Phylogenetic analysis of the pure culture was performed. Results A heterotrophic nitrifier, named Bacillus sp. LY, was newly isolated from the membrane bioreactor system in which the efficiency of TN removal was up to 80%. After 24-day, incubation, the removal efficiency of COD by Bacillus sp. LYwas 71.7%. The ammonium nitrogen removal rate after assimilation nearly ceased by Bacillus sp. LYwas 74.7%.The phylogenetic tree of Bacillus sp. LY and the neighbouring nitrifiers were given. Conclusions The batch test results indicate that Bacillus sp. LY can utilize the organic carbon as the source of assimilation when it grows on glucose and ammonium chloride medium accompanying the formation of oxidized-nitrogen. It also can denitrify nitrate while nitrifying. Bacillus sp. LY may become a new bacterial resource for heterotrophic nitrification and play a bioremediation role in nutrient removal.

  11. 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.

  12. Analysis of nitrification efficiency and microbial community in a membrane bioreactor fed with low COD/N-ratio wastewater.

    Directory of Open Access Journals (Sweden)

    Jinxing Ma

    Full Text Available In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR. Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress. The enrichment of nitrifiers in an MBR with a low COD/N-ratio demonstrated that this condition stimulated nitrification, and that the community distribution of ammonia oxidizing bacteria (AOB and nitrite oxidizing bacteria (NOB resulted in faster nitrite uptake rates. Further, ammonia oxidation was the rate-limiting step during the full nitrification.

  13. Bioreactor

    Science.gov (United States)

    1996-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues currently being cultured in rotating bioreactors by investigators

  14. Pilot and full scale applications of sulfur-based autotrophic denitrification process for nitrate removal from activated sludge process effluent.

    Science.gov (United States)

    Sahinkaya, Erkan; Kilic, Adem; Duygulu, Bahadir

    2014-09-01

    Sulfur-based autotrophic denitrification of nitrified activated sludge process effluent was studied in pilot and full scale column bioreactors. Three identical pilot scale column bioreactors packed with varying sulfur/lime-stone ratios (1/1-3/1) were setup in a local wastewater treatment plant and the performances were compared under varying loading conditions for long-term operation. Complete denitrification was obtained in all pilot bioreactors even at nitrate loading of 10 mg NO3(-)-N/(L.h). When the temperature decreased to 10 °C during the winter time at loading of 18 mg NO3(-)-N/(L.h), denitrification efficiency decreased to 60-70% and the bioreactor with S/L ratio of 1/1 gave slightly better performance. A full scale sulfur-based autotrophic denitrification process with a S/L ratio of 1/1 was set up for the denitrification of an activated sludge process effluent with a flow rate of 40 m(3)/d. Almost complete denitrification was attained with a nitrate loading rate of 6.25 mg NO3(-)-N/(L.h). PMID:24862952

  15. Comparison of membrane biofouling of autotrophic nitrifying and heterotrophic denitrifying sludge%自养硝化与异养反硝化污泥膜污染特性的对比

    Institute of Scientific and Technical Information of China (English)

    王朝朝; 李军

    2013-01-01

    Batch filtration tests were carried out to investigate the membrane biofouling characterizations of nitrifying and denitrifying sludge from a continuous-flow nitrogen and phosphorus removal bench-scale membrane bioreactor under the stable operation.Biofouling mechanisms of denitrifying sludge by using different electron donors were also analyzed and discussed.The test results show that the denitrifying rate by using the acetic acid as the electron donor is 13.8 mg/(g·h),higher than methanol 3.4 mg/(g·h),ethanol 10.2 mg/(g·h) at 25 C; compared with nitrifying sludge,the protein of soluble microbial products from denitrifying sludges increases in the range of < 1 kDa and > 100 kDa,being the main factor for the increased resistance of soluble substances in the mixed liquor,thereby increasing the pore blocking resistance of soluble substances,and denitrification process by using the methanol as the electron donor is the most obvious.It is also found that the decrease of extracellular polymeric substances produced through denitrification processes and relative hydrophobicity of carbohydrate and protein substances becomes the main factor for the decreased resistance of SS fraction in the mixed liquor; the relative molecular mass distributions of extracellular polymericsubstances becomes slightly different after denitrification,but Fourier transform infrared spectroscopy of the functional groups of extracellular polymeric substances shows that the chemical composition of extracellular polymeric substances produced by nitrifying sludge and denitrifying sludge by using three different electron donors have not changed.The modified fouling index of denitrifying sludge by using acetic as the electron donor becomes the lowest one.%以同步脱氮除磷连续流膜生物反应器小试稳定运行时的污泥为考查对象,采用序批式过滤试验对比考查硝化污泥与反硝化污泥的污染特性,并对不同电子供体下反硝化污泥

  16. Bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Jamaleddine, E. [McGill Univ., Montreal, PQ (Canada). Dept. of Bioresource Engineering

    2010-07-01

    Composting is once again gaining interest among ecological engineers in view of greener industrial and residential activities. Uniform composting is needed to ensure decomposition and to keep the whole system at the same composting stage. A homogeneous temperature must be maintained throughout the media. A bioreactor design consisting of a heater core made of copper tubing was designed and tested. Two four-inch holes were made at the top and bottom of the barrel to allow air to flow through the system and promote aerobic composting. Once composting began and temperature increased, the water began to flow through the copper piping and the core heat was distributed throughout the medium. Three thermocouples were inserted at different heights on a 200 litre plastic barrel fitted with the aforementioned apparatus. Temperature variations were found to be considerably lower when the apparatus was operated with the heat redistribution system, enabling uniform composting, accelerating the process and reducing the risks of pathogenic or other contaminants remaining active in the barrels.

  17. Nitrification in brackish water recirculating aquaculture system integrated with activated packed bed bioreactor.

    Science.gov (United States)

    Rejish Kumar, V J; Joseph, Valsamma; Philip, Rosamma; Bright Singh, I S

    2010-01-01

    Recirculation aquaculture systems (RAS) depend on nitrifying biofilters for the maintenance of water quality, increased biosecurity and environmental sustainability. To satisfy these requirements a packed bed bioreactor (PBBR) activated with indigenous nitrifying bacterial consortia has been developed and commercialized for operation under different salinities for instant nitrification in shrimp and prawn hatchery systems. In the present study the nitrification efficiency of the bioreactor was tested in a laboratory level recirculating aquaculture system for the rearing of Penaeus monodon for a period of two months under higher feeding rates and no water exchange. Rapid setting up of nitrification was observed during the operation, as the volumetric total ammonia nitrogen removal rates (VTR) increased with total ammonia nitrogen (TAN) production in the system. The average Volumetric TAN Removal Rates (VTR) at the feeding rate of 160 g/day from 54-60th days of culture was 0.1533+/-0.0045 kg TAN/m(3)/day. The regression between VTR and TAN explained 86% variability in VTR (P<0.001). The laboratory level RAS demonstrated here showed high performance both in terms of shrimp biomass yield and nitrification and environmental quality maintenance. Fluorescent in-situ Hybridization analysis of the reactor biofilm ensured the presence of autotrophic nitrifier groups such as Nitrosococcus mobilis lineage, Nitrobacter spp and phylum Nitrospira, the constituent members present in the original consortia used for activating the reactors. This showed the stability of the consortia on long term operation. PMID:20150717

  18. Nitrogen removal through different pathways in an aged refuse bioreactor treating mature landfill leachate.

    Science.gov (United States)

    Xie, Bing; Lv, Zhuo; Hu, Chong; Yang, Xuezhi; Li, Xiangzhen

    2013-10-01

    In this study, an aged refuse bioreactor was constructed to remove nitrogen in a mature landfill leachate. The nitrogen removal efficiency and the microbial community composition in the bioreactor were investigated. The results showed that the aged refuse bioreactor removed more than 90 % of total nitrogen in the leachate under the nitrogen loading rate (NLR) of 0.74 g/kg (vs) day, and the total nitrogen removal rate decreased to 62.2 % when NLR increased up to 2.03 g/kg (vs) day. Quantitative polymerase chain reaction results showed that the average cell number of ammonia-oxidizing bacteria in the bioreactor was 1.58 × 10(8) cells/g, which accounted for 0.41 % of total bacteria. The number of anammox bacteria in the reactor was 1.09 × 10(8) cells/g, which accounted for 0.27 % of total bacteria. Isotopic (15)N tracing experiments showed that nearly 10 % of nitrogen was removed by anammox. High-throughout 454 pyrosequencing revealed that the predominant bacteria in the bioreactor were Proteobacteria, Chloroflexi, Actinobacteria, Bacteroidetes, and Gemmatimonadetes, including various nitrifiers and denitrifiers with diverse heterotrophic and autotrophic metabolic pathways, supporting that nitrogen was removed through different pathways in this aged refuse bioreactor.

  19. Association of running manner with bacterial community dynamics in a partial short-term nitrifying bioreactor for treatment of piggery wastewater with high ammonia content.

    Science.gov (United States)

    Du, Wei-Li; Huang, Qiang; Miao, Li-Li; Liu, Ying; Liu, Zhi-Pei

    2016-12-01

    Optimization of running parameters in a bioreactor requires detailed understanding of microbial community dynamics during the startup and running periods. Using a novel piggery wastewater treatment system termed "UASB + SHARON + ANAMMOX" constructed in our laboratory, we investigated microbial community dynamics using the Illumina MiSeq method, taking activated sludge samples at ~2-week intervals during a ~300-day period. Ammonia-oxidizing bacteria (AOB) were further investigated by quantification of AOB amoA genes and construction of gene clone libraries. Major changes in bacterial community composition and dynamics occurred when running manner was changed from continuous flow manner (CFM) to sequencing batch manner (SBM), and when effluent from an upflow anaerobic sludge blanket (UASB) reactor for practical treatment of real piggery wastewater was used as influent; differences among these three experimental groups were significant (R (2)  = 0.94, p < 0.01). When running manner was changed from CFM to SBM, relative abundance of the genus Nitrospira decreased sharply from 18.1 % on day 116 to 1.5 % on day 130, and to undetectable level thereafter. Relative abundance of the genus Nitrosomonas increased from ~0.67 % during the CFM period to 8.0 % by day 220, and thereafter decreased to a near-constant ~1.6 %. Environmental factors such as load ammonia, effluent ammonia, effluent nitrite, UASB effluent, pH, and DO levels collectively drove bacterial community dynamics and contributed to maintenance of effluent NH4 (+)-N/NO2 (-)-N ratio ~1. Theses results might provide useful clues for the control of the startup processes and maintaining high efficiency of such bioreactors. PMID:27637946

  20. 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.

  1. Effects of Cr(III) and CR(VI) on nitrification inhibition as determined by SOUR, function-specific gene expression and 16S rRNA sequence analysis of wastewater nitrifying enrichments

    Science.gov (United States)

    The effect of Cr(III) and Cr(VI) on ammonia oxidation, the transcriptional responses of functional genes involved in nitrification and changes in 16S rRNA level sequences were examined in nitrifying enrichment cultures. The nitrifying bioreactor was operated as a continuous react...

  2. Activated packed bed bioreactor for rapid nitrification in brackish water hatchery systems.

    Science.gov (United States)

    Kumar, V J Rejish; Achuthan, Cini; Manju, N J; Philip, Rosamma; Singh, I S Bright

    2009-03-01

    A packed bed bioreactor (PBBR) was developed for rapid establishment of nitrification in brackish water hatchery systems in the tropics. The reactors were activated by immobilizing ammonia-oxidizing (AMONPCU-1) and nitrite-oxidizing (NIONPCU-1) bacterial consortia on polystyrene and low-density polyethylene beads, respectively. Fluorescence in situ hybridization demonstrated the presence of autotrophic nitrifiers belong to Nitrosococcus mobilis, lineage of beta ammonia oxidizers and nitrite oxidizer Nitrobacter sp. in the consortia. The activated reactors upon integration to the hatchery system resulted in significant ammonia removal (P systems. With spent water the reactors could establish nitrification with high percentage removal of ammonia (78%), nitrite (79%) and BOD (56%) within 7 days of initiation of the process. PBBR is configured in such a way to minimize the energy requirements for continuous operation by limiting the energy inputs to a single stage pumping of water and aeration to the aeration cells. The PBBR shall enable hatchery systems to operate under closed recirculating mode and pave the way for better water management in the aquaculture industry. PMID:19039611

  3. Development of a microbiological ammonium to nitrate recycling bioreactor for space capsules

    International Nuclear Information System (INIS)

    Since 1988, the Expertise group of Molecular and Cellular Biology (MCB) is an important partner in the development of the Micro-Ecological Life Support System Alternative (MELiSSA). The MELiSSA was designed to allow a small crew to survive on an Antarctic, lunar or Mars outpost, and is a joint research project currently fostered by the European Space Agency, ESA. The MELiSSA functions through a series of five interconnected compartments, of which four are microbial bioreactors and was engineered to degrade organic waste, regenerate the outpost's atmosphere and water, and provide the crew with an additional vegetarian diet. The bioreactor of the third compartment provides the edible cyanobacteria and plants of the fourth compartment with nitrate instead of ammonium as a source of nitrogen. The two bacteria responsible for the biological transformation of ammonium to nitrate (nitrification) are Nitrosomonas europaea and Nitrobacter winogradskyi. Since all MELiSSA-reactors are to be relied on for a period of several years, reactor operation is to be studied exhaustively to allow optimal process- and reactor performance. Therefore, a pilot reactor for the third compartment was engineered and constructed at the Universitat Autonoma de Barcelona (UAB), where the pilot plant of the MELiSSA is installed. The reactor was able to perform nitrification with high efficiency for the entire trial period of nearly five years and was the subject of this study. Collaboration between the unit of MCB and researchers at Universitat Autonoma de Barcelona (UAB) allowed the development and validation of a mathematical model for the third compartment of the MELiSSA. A mathematical model will allow optimizing reactor operation and reactor performance even further. A Real-Time Quantitative Polymerase Chain Reaction (Q-PCR) was developed at MCB that allowed the quantitative assessment of the relative distribution of the two autotrophic nitrifying bacterial species along the reactor's packed

  4. Effect of carrier fill ratio on biofilm properties and performance of a hybrid fixed-film bioreactor treating coal gasification wastewater for the removal of COD, phenols and ammonia-nitrogen.

    Science.gov (United States)

    Rava, E; Chirwa, E

    2016-01-01

    The purpose of this study was to determine the effect different biofilm carrier filling ratios would have on biofilm morphology and activity and bacterial diversity in a hybrid fixed-film bioreactor treating high strength coal gasification wastewater (CGWW) for the removal of chemical oxygen demand (COD), phenols and ammonia-nitrogen. Results showed that a carrier fill of 70% formed a 'compact' biofilm, a 50% fill formed a 'rippling' biofilm and a 30% fill formed a 'porous' biofilm. The highest microbial activity was obtained with a 50% carrier fill supporting a relatively thin biofilm. The highest level of biofilm bound metals were aluminium, silicon, calcium and iron in the 'compact' biofilm; nitrogen, magnesium, chloride, sodium and potassium in the 'rippling' biofilm, and copper in the 'porous' biofilm. The bioreactor improved the quality of the CGWW by removing 49% and 78% of the COD and phenols, respectively. However, no significant amount of ammonia-nitrogen was removed since nitrification did not take place due to heterotrophic bacteria out-competing autotrophic nitrifying bacteria in the biofilm. The dominant heterotrophic genera identified for all three carrier filling ratios were Thauera, Pseudaminobacter, Pseudomonas and Diaphorobacter. PMID:27191568

  5. Modelling cometabolic biotransformation of organic micropollutants in nitrifying reactors.

    Science.gov (United States)

    Fernandez-Fontaina, E; Carballa, M; Omil, F; Lema, J M

    2014-11-15

    Cometabolism is the ability of microorganisms to degrade non-growth substrates in the presence of primary substrates, being the main removal mechanism behind the biotransformation of organic micropollutants in wastewater treatment plants. In this paper, a cometabolic Monod-type kinetics, linking biotransformation of micropollutants with primary substrate degradation, was applied to a highly enriched nitrifying activated sludge (NAS) reactor operated under different operational conditions (hydraulic retention time (HRT) and nitrifying activity). A dynamic model of the bioreactor was built taking into account biotransformation, sorption and volatilization. The micropollutant transformation capacity (Tc), the half-saturation constant (Ksc) and the solid-liquid partitioning coefficient (Kd) of several organic micropollutants were estimated at 25 °C using an optimization algorithm to fit experimental data to the proposed model with the cometabolic Monod-type biotransformation kinetics. The cometabolic Monod-type kinetic model was validated under different HRTs (1.0-3.7 d) and nitrification rates (0.12-0.45 g N/g VSS d), describing more accurately the fate of those compounds affected by the biological activity of nitrifiers (ibuprofen, naproxen, erythromycin and roxithromycin) compared to the commonly applied pseudo-first order micropollutant biotransformation kinetics, which does not link biotransformation of micropollutants to consumption of primary substrate. Furthermore, in contrast to the pseudo-first order biotransformation constant (k(biol)), the proposed cometabolic kinetic coefficients are independent of operational conditions such as the nitrogen loading rate applied. Also, the influence of the kinetic parameters on the biotransformation efficiency of NAS reactors, defined as the relative amount of the total inlet micropollutant load being biotransformed, was assessed considering different HRTs and nitrification rates. PMID:25150522

  6. NASA Bioreactor

    Science.gov (United States)

    1996-01-01

    Close-up view of the interior of a NASA Bioreactor shows the plastic plumbing and valves (cylinders at center) to control fluid flow. A fresh nutrient bag is installed at top; a flattened waste bag behind it will fill as the nutrients are consumed during the course of operation. The drive chain and gears for the rotating wall vessel are visible at bottom center center. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  7. Effect of Storm Events on Benthic Nitrifying Activity

    OpenAIRE

    Cooper, A. Bryce

    1983-01-01

    Storm events resulted in a marked reduction in the benthic nitrifying activity of a stream receiving geothermal inputs of ammonium. Subsequently, nitrifying activity demonstrated a logarithmic increase until a stable activity was reached 10 to 12 days after the storm event. The rate of increase of poststorm nitrifying activity was used to calculate the nitrifier growth rate in situ (0.0075 to 0.0116 h−1) which was lower than the growth rates observed for laboratory cultures of nitrifying bact...

  8. Bioreactor principles

    Science.gov (United States)

    2001-01-01

    Cells cultured on Earth (left) typically settle quickly on the bottom of culture vessels due to gravity. In microgravity (right), cells remain suspended and aggregate to form three-dimensional tissue. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  9. 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...

  10. 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.

  11. Autotrophic processes in meromictic Big Soda Lake, Nevada.

    Science.gov (United States)

    Cloern, J.E.; Cole, B.E.; Oremland, R.S.

    1983-01-01

    Daily rates of oxygenic photosynthesis (OP) by phytoplankton, anoxygenic photosynthesis (AP) by purple sulfur bacteria, and chemoautotrophic productivity (CP = dark CO2 assimilation) were measured once each season. Total daily productivity and the relative importance of each autotrophic process varied with seasonal changes in vertical mixing, light availability, and the biomass of phototrophs. Daily productivity was highest (2830 mg C.m-2) and was dominated by OP in winter when the mixolimnion was isothermal, the biomass of phytoplankton was high, and the biomass of purple sulfur bacteria was low. During the summer-fall period of thermal stratification, phytoplankton biomass decreased, a plate of purple sulfur bacteria formed below the oxycline, and daily rates of dark CO2 assimilation (CP = 390-680 mg C.m-2) exceeded phototrophic productivity (OP + AP = 200-370 mg C.m-2). Total annual productivity was approx 500 g C.m-2, of which 60% was produced by phytoplankton (mostly in winter), 30% by chemoautotrophs (nitrifying and sulfur-oxidizing bacteria), and only 10% by photosynthetic bacteria. -Authors

  12. NASA Bioreactor

    Science.gov (United States)

    1998-01-01

    Bioreactor Demonstration System (BDS) comprises an electronics module, a gas supply module, and the incubator module housing the rotating wall vessel and its support systems. Nutrient media are pumped through an oxygenator and the culture vessel. The shell rotates at 0.5 rpm while the irner filter typically rotates at 11.5 rpm to produce a gentle flow that ensures removal of waste products as fresh media are infused. Periodically, some spent media are pumped into a waste bag and replaced by fresh media. When the waste bag is filled, an astronaut drains the waste bag and refills the supply bag through ports on the face of the incubator. Pinch valves and a perfusion pump ensure that no media are exposed to moving parts. An Experiment Control Computer controls the Bioreactor, records conditions, and alerts the crew when problems occur. The crew operates the system through a laptop computer displaying graphics designed for easy crew training and operation. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. See No. 0101825 for a version with major elements labeled, and No. 0103180 for an operational schematic. 0101816

  13. NASA Bioreactor

    Science.gov (United States)

    1998-01-01

    Biotechnology Specimen Temperature Controller (BSTC) will cultivate cells until their turn in the bioreactor; it can also be used in culturing experiments that do not require the bioreactor. The BSTC comprises four incubation/refrigeration chambers individually set at 4 to 50 deg. C (near-freezing to above body temperature). Each chamber holds three rugged tissue chamber modules (12 total), clear Teflon bags holding 30 ml of growth media, all positioned by a metal frame. Every 7 to 21 days (depending on growth rates), an astronaut uses a shrouded syringe and the bags' needleless injection ports to transfer a few cells to a fresh media bag, and to introduce a fixative so that the cells may be studied after flight. The design also lets the crew sample the media to measure glucose, gas, and pH levels, and to inspect cells with a microscope. The controller is monitored by the flight crew through a 23-cm (9-inch) color computer display on the face of the BSTC. This view shows the BTSC with the front panel open. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  14. Kinetic evaluation of nitrification performance in an immobilized cell membrane bioreactor.

    Science.gov (United States)

    Güven, D; Ubay Çokgör, E; Sözen, S; Orhon, D

    2016-01-01

    High rate membrane bioreactor (MBR) systems operated at extremely low sludge ages (superfast membrane bioreactors (SFMBRs)) are inefficient to achieve nitrogen removal, due to insufficient retention time for nitrifiers. Moreover, frequent chemical cleaning is required due to high biomass flux. This study aims to satisfy the nitrification in SFMBRs by using sponge as carriers, leading to the extension of the residence time of microorganisms. In order to test the limits of nitrification, bioreactor was run under 52, 5 and 2 days of carrier residence time (CRT), with a hydraulic retention time of 6 h. Different degrees of nitrification were obtained for different CRTs. Sponge immobilized SFMBR operation with short CRT resulted in partial nitrification indicating selective dominancy of ammonia oxidizers. At higher CRT, simultaneous nitrification-denitrification was achieved when accompanying with oxygen limitation. Process kinetics was determined through evaluation of the results by a modeling study. Nitrifier partition in the reactor was also identified by model calibration.

  15. Microbial community analysis of a full-scale DEMON bioreactor.

    Science.gov (United States)

    Gonzalez-Martinez, Alejandro; Rodriguez-Sanchez, Alejandro; Muñoz-Palazon, Barbara; Garcia-Ruiz, Maria-Jesus; Osorio, Francisco; van Loosdrecht, Mark C M; Gonzalez-Lopez, Jesus

    2015-03-01

    Full-scale applications of autotrophic nitrogen removal technologies for the treatment of digested sludge liquor have proliferated during the last decade. Among these technologies, the aerobic/anoxic deammonification process (DEMON) is one of the major applied processes. This technology achieves nitrogen removal from wastewater through anammox metabolism inside a single bioreactor due to alternating cycles of aeration. To date, microbial community composition of full-scale DEMON bioreactors have never been reported. In this study, bacterial community structure of a full-scale DEMON bioreactor located at the Apeldoorn wastewater treatment plant was analyzed using pyrosequencing. This technique provided a higher-resolution study of the bacterial assemblage of the system compared to other techniques used in lab-scale DEMON bioreactors. Results showed that the DEMON bioreactor was a complex ecosystem where ammonium oxidizing bacteria, anammox bacteria and many other bacterial phylotypes coexist. The potential ecological role of all phylotypes found was discussed. Thus, metagenomic analysis through pyrosequencing offered new perspectives over the functioning of the DEMON bioreactor by exhaustive identification of microorganisms, which play a key role in the performance of bioreactors. In this way, pyrosequencing has been proven as a helpful tool for the in-depth investigation of the functioning of bioreactors at microbiological scale.

  16. 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...

  17. Cyanate as an energy source for nitrifiers.

    Science.gov (United States)

    Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico; Pogoda, Mario; Han, Ping; von Bergen, Martin; Lagkouvardos, Ilias; Karst, Søren M; Galushko, Alexander; Koch, Hanna; Berry, David; Daims, Holger; Wagner, Michael

    2015-08-01

    Ammonia- and nitrite-oxidizing microorganisms are collectively responsible for the aerobic oxidation of ammonia via nitrite to nitrate and have essential roles in the global biogeochemical nitrogen cycle. The physiology of nitrifiers has been intensively studied, and urea and ammonia are the only recognized energy sources that promote the aerobic growth of ammonia-oxidizing bacteria and archaea. Here we report the aerobic growth of a pure culture of the ammonia-oxidizing thaumarchaeote Nitrososphaera gargensis using cyanate as the sole source of energy and reductant; to our knowledge, the first organism known to do so. Cyanate, a potentially important source of reduced nitrogen in aquatic and terrestrial ecosystems, is converted to ammonium and carbon dioxide in Nitrososphaera gargensis by a cyanase enzyme that is induced upon addition of this compound. Within the cyanase gene family, this cyanase is a member of a distinct clade also containing cyanases of nitrite-oxidizing bacteria of the genus Nitrospira. We demonstrate by co-culture experiments that these nitrite oxidizers supply cyanase-lacking ammonia oxidizers with ammonium from cyanate, which is fully nitrified by this microbial consortium through reciprocal feeding. By screening a comprehensive set of more than 3,000 publically available metagenomes from environmental samples, we reveal that cyanase-encoding genes clustering with the cyanases of these nitrifiers are widespread in the environment. Our results demonstrate an unexpected metabolic versatility of nitrifying microorganisms, and suggest a previously unrecognized importance of cyanate in cycling of nitrogen compounds in the environment.

  18. Cyanate as an energy source for nitrifiers.

    Science.gov (United States)

    Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico; Pogoda, Mario; Han, Ping; von Bergen, Martin; Lagkouvardos, Ilias; Karst, Søren M; Galushko, Alexander; Koch, Hanna; Berry, David; Daims, Holger; Wagner, Michael

    2015-08-01

    Ammonia- and nitrite-oxidizing microorganisms are collectively responsible for the aerobic oxidation of ammonia via nitrite to nitrate and have essential roles in the global biogeochemical nitrogen cycle. The physiology of nitrifiers has been intensively studied, and urea and ammonia are the only recognized energy sources that promote the aerobic growth of ammonia-oxidizing bacteria and archaea. Here we report the aerobic growth of a pure culture of the ammonia-oxidizing thaumarchaeote Nitrososphaera gargensis using cyanate as the sole source of energy and reductant; to our knowledge, the first organism known to do so. Cyanate, a potentially important source of reduced nitrogen in aquatic and terrestrial ecosystems, is converted to ammonium and carbon dioxide in Nitrososphaera gargensis by a cyanase enzyme that is induced upon addition of this compound. Within the cyanase gene family, this cyanase is a member of a distinct clade also containing cyanases of nitrite-oxidizing bacteria of the genus Nitrospira. We demonstrate by co-culture experiments that these nitrite oxidizers supply cyanase-lacking ammonia oxidizers with ammonium from cyanate, which is fully nitrified by this microbial consortium through reciprocal feeding. By screening a comprehensive set of more than 3,000 publically available metagenomes from environmental samples, we reveal that cyanase-encoding genes clustering with the cyanases of these nitrifiers are widespread in the environment. Our results demonstrate an unexpected metabolic versatility of nitrifying microorganisms, and suggest a previously unrecognized importance of cyanate in cycling of nitrogen compounds in the environment. PMID:26222031

  19. Bioreactor landfill

    Institute of Scientific and Technical Information of China (English)

    WANG Hao; XING Kai; Anthony Adzomani

    2004-01-01

    Following the population expansion, there is a growing threat brought by municipal solid waste (MSW) against environment and human health. Sanitary landfill is the most important method of MSW disposal in China. In contrast to the conventional landfill, this paper introduces a new technique named bioreactor landfill (BL). Mechanisms, operation conditions as well as the advantages and disadvantages of BL are also discussed in this paper.

  20. High-efficient nitrogen removal by coupling enriched autotrophic-nitrification and aerobic-denitrification consortiums at cold temperature.

    Science.gov (United States)

    Zou, Shiqiang; Yao, Shuo; Ni, Jinren

    2014-06-01

    This study paid particular attention to total nitrogen removal at low temperature (10°C) by excellent coupling of enriched autotrophic nitrifying and heterotrophic denitrifying consortiums at sole aerobic condition. The maximum specific nitrifying rate of the nitrifying consortium reached 8.85mgN/(gSSh). Further test in four identical lab-scale sequencing batch reactors demonstrated its excellent performance for bioaugmentation in potential applications. On the other hand, the aerobic denitrifying consortium could achieve a specific denitrifying rate of 32.93mgN/(gSSh) under dissolved oxygen of 1.0-1.5mg/L at 10°C. Coupling both kinds of consortiums was proved very successful for a perfect total nitrogen (TN) removal at COD/N of 4 and dissolved oxygen of 1.5-4.5mg/L, which was hardly reached by any single consortium reported previously. The encouraging results from coupling aerobic consortiums implied a huge potential in practical treatment of low-strength domestic wastewater (200-300mg/L COD) during wintertime.

  1. Cyanate as energy source for nitrifiers

    OpenAIRE

    Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico; Pogoda, Mario; Han, Ping; von Bergen, Martin; Lagkouvardos, Ilias; Karst, Søren M.; Galushko, Alexander; Koch, Hanna; BERRY, David; Daims, Holger; Wagner, Michael

    2015-01-01

    Ammonia- and nitrite-oxidizers are collectively responsible for the aerobic oxidation of ammonia via nitrite to nitrate and play essential roles for the global biogeochemical nitrogen cycle. The physiology of these nitrifying microbes has been intensively studied since the first experiments of Sergei Winogradsky more than a century ago. Urea and ammonia are the only recognized energy sources that promote the aerobic growth of ammonia-oxidizing bacteria and archaea. Here we report the aerobic ...

  2. Cyanate as energy source for nitrifiers

    Science.gov (United States)

    Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico; Pogoda, Mario; Han, Ping; von Bergen, Martin; Lagkouvardos, Ilias; Karst, Søren M.; Galushko, Alexander; Koch, Hanna; Berry, David; Daims, Holger; Wagner, Michael

    2015-01-01

    Ammonia- and nitrite-oxidizers are collectively responsible for the aerobic oxidation of ammonia via nitrite to nitrate and play essential roles for the global biogeochemical nitrogen cycle. The physiology of these nitrifying microbes has been intensively studied since the first experiments of Sergei Winogradsky more than a century ago. Urea and ammonia are the only recognized energy sources that promote the aerobic growth of ammonia-oxidizing bacteria and archaea. Here we report the aerobic growth of a pure culture of the ammonia-oxidizing thaumarchaeote Nitrososphaera gargensis1 on cyanate as the sole source of energy and reductant, the first organism known to do so. Cyanate, which is a potentially important source of reduced nitrogen in aquatic and terrestrial ecosystems2, is converted to ammonium and CO2 by this archaeon using a cyanase that is induced upon addition of this compound. Within the cyanase gene family, this cyanase is a member of a distinct clade that also contains cyanases of nitrite-oxidizing bacteria of the genus Nitrospira. We demonstrate by co-culture experiments that these nitrite-oxidizers supply ammonia-oxidizers lacking cyanase with ammonium from cyanate, which is fully nitrified by this consortium through reciprocal feeding. Screening of a comprehensive set of more than 3,000 publically available metagenomes from environmental samples revealed that cyanase-encoding genes clustering with the cyanases of these nitrifiers are widespread in the environment. Our results demonstrate an unexpected metabolic versatility of nitrifying microbes and suggest a previously unrecognized importance of cyanate for N-cycling in the environment. PMID:26222031

  3. Agricultural land usage transforms nitrifier population ecology.

    Science.gov (United States)

    Bertagnolli, Anthony D; McCalmont, Dylan; Meinhardt, Kelley A; Fransen, Steven C; Strand, Stuart; Brown, Sally; Stahl, David A

    2016-06-01

    Application of nitrogen fertilizer has altered terrestrial ecosystems. Ammonia is nitrified by ammonia and nitrite-oxidizing microorganisms, converting ammonia to highly mobile nitrate, contributing to the loss of nitrogen, soil nutrients and production of detrimental nitrogen oxides. Mitigating these costs is of critical importance to a growing bioenergy industry. To resolve the impact of management on nitrifying populations, amplicon sequencing of markers associated with ammonia and nitrite-oxidizing taxa (ammonia monooxygenase-amoA, nitrite oxidoreductase-nxrB, respectively) was conducted from long-term managed and nearby native soils in Eastern Washington, USA. Native nitrifier population structure was altered profoundly by management. The native ammonia-oxidizing archaeal community (comprised primarily by Nitrososphaera sister subclusters 1.1 and 2) was displaced by populations of Nitrosopumilus, Nitrosotalea and different assemblages of Nitrososphaera (subcluster 1.1, and unassociated lineages of Nitrososphaera). A displacement of ammonia-oxidizing bacterial taxa was associated with management, with native groups of Nitrosospira (cluster 2 related, cluster 3A.2) displaced by Nitrosospira clusters 8B and 3A.1. A shift in nitrite-oxidizing bacteria (NOB) was correlated with management, but distribution patterns could not be linked exclusively to management. Dominant nxrB sequences displayed only distant relationships to other NOB isolates and environmental clones. PMID:26526405

  4. Simultaneous heterotrophic and sulfur-oxidizing autotrophic denitrification process for drinking water treatment: control of sulfate production.

    Science.gov (United States)

    Sahinkaya, Erkan; Dursun, Nesrin; Kilic, Adem; Demirel, Sevgi; Uyanik, Sinan; Cinar, Ozer

    2011-12-15

    A long-term performance of a packed-bed bioreactor containing sulfur and limestone was evaluated for the denitrification of drinking water. Autotrophic denitrification rate was limited by the slow dissolution rate of sulfur and limestone. Dissolution of limestone for alkalinity supplementation increased hardness due to release of Ca(2+). Sulfate production is the main disadvantage of the sulfur autotrophic denitrification process. The effluent sulfate concentration was reduced to values below drinking water guidelines by stimulating the simultaneous heterotrophic and autotrophic denitrification with methanol supplementation. Complete removal of 75 mg/L NO(3)-N with effluent sulfate concentration of around 225 mg/L was achieved when methanol was supplemented at methanol/NO(3)-N ratio of 1.67 (mg/mg), which was much lower than the theoretical value of 2.47 for heterotrophic denitrification. Batch studies showed that sulfur-based autotrophic NO(2)-N reduction rate was around three times lower than the reduction rate of NO(3)-N, which led to NO(2)-N accumulation at high loadings.

  5. Hydrodynamic characteristics of airlift nitrifying reactor using carrier-induced granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Jin Rencun [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Environmental Science, Hangzhou Normal University, Hangzhou 310036 (China); Zheng Ping [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China)], E-mail: pzheng@zju.edu.cn; Mahmood, Qaisar; Zhang Lei [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China)

    2008-09-15

    Since nitrification is the rate-limiting step in the biological nitrogen removal from wastewater, many studies have been conducted on the immobilization of nitrifying bacteria. A laboratory-scale investigation was carried out to scrutinize the effectiveness of activated carbon carrier addition for granulation of nitrifying sludge in a continuous-flow airlift bioreactor and to study the hydrodynamics of the reactor with carrier-induced granules. The results showed that the granular sludge began to appear and matured 60 and 108 days, respectively, after addition of carriers, while no granule was observed in the absence of carriers in the control test. The mature granules had a diameter of 0.5-5 mm (1.6 mm in average), settling velocity 22.3-55.8 m h{sup -1} and specific gravity of 1.086. The relationship between the two important hydrodynamic coefficients, i.e. gas holdup and liquid circulation velocity, and the superficial gas velocity were established by a simple model and were confirmed experimentally. The model also could predict the critical superficial gas velocity for liquid circulation and that for granules circulation, with respective values of 1.017 and 2.662 cm min{sup -1}, accurately.

  6. Bioreactors addressing diabetes mellitus.

    Science.gov (United States)

    Minteer, Danielle M; Gerlach, Jorg C; Marra, Kacey G

    2014-11-01

    The concept of bioreactors in biochemical engineering is a well-established process; however, the idea of applying bioreactor technology to biomedical and tissue engineering issues is relatively novel and has been rapidly accepted as a culture model. Tissue engineers have developed and adapted various types of bioreactors in which to culture many different cell types and therapies addressing several diseases, including diabetes mellitus types 1 and 2. With a rising world of bioreactor development and an ever increasing diagnosis rate of diabetes, this review aims to highlight bioreactor history and emerging bioreactor technologies used for diabetes-related cell culture and therapies.

  7. Influence of biofilm thickness on micropollutants removal in nitrifying MBBRs

    OpenAIRE

    Torresi, Elena; Andersen, Henrik Rasmus; Smets, Barth F.; Plósz, Benedek G.; Christensson, M.

    2015-01-01

    The removal of pharmaceuticals was investigated in nitrifying Moving Bed Biofilm Reactors (MBBRs) containing carriers with different biofilm thicknesses. The biofilm with the thinnest thickness was found to have the highest nitrification and biotransformation rate for some key pharmaceuticals. Microbial analysis revealed a different relative abundance of nitrifying guilds in the different carriers, suggesting the importance of nitrite oxidizing bacteria in removal of micropollutants.

  8. Cyanate as energy source for nitrifiers

    DEFF Research Database (Denmark)

    Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico;

    2015-01-01

    Ammonia- and nitrite-oxidizing microorganisms are collectively responsible for the aerobic oxidation of ammonia via nitrite to nitrate and have essential roles in the global biogeochemical nitrogen cycle. The physiology of nitrifiers has been intensively studied, and urea and ammonia are the only...... organism known to do so. Cyanate, a potentially important source of reduced nitrogen in aquatic and terrestrial ecosystems2, is converted to ammonium and carbon dioxide in Nitrososphaera gargensis by a cyanase enzyme that is induced upon addition of this compound. Within the cyanase gene family...

  9. Bioreactors Addressing Diabetes Mellitus

    OpenAIRE

    Minteer, Danielle M.; Gerlach, Jorg C; Marra, Kacey G.

    2014-01-01

    The concept of bioreactors in biochemical engineering is a well-established process; however, the idea of applying bioreactor technology to biomedical and tissue engineering issues is relatively novel and has been rapidly accepted as a culture model. Tissue engineers have developed and adapted various types of bioreactors in which to culture many different cell types and therapies addressing several diseases, including diabetes mellitus types 1 and 2. With a rising world of bioreactor develop...

  10. Impact of Aquifer Heterogeneities on Autotrophic Denitrification.

    Science.gov (United States)

    McCarthy, A.; Roques, C.; Selker, J. S.; Istok, J. D.; Pett-Ridge, J. C.

    2015-12-01

    Nitrate contamination in groundwater is a big challenge that will need to be addressed by hydrogeologists throughout the world. With a drinking water standard of 10mg/L of NO3-, innovative techniques will need to be pursued to ensure a decrease in drinking water nitrate concentration. At the pumping site scale, the influence and relationship between heterogeneous flow, mixing, and reactivity is not well understood. The purpose of this project is to incorporate both physical and chemical modeling techniques to better understand the effect of aquifer heterogeneities on autotrophic denitrification. We will investigate the link between heterogeneous hydraulic properties, transport, and the rate of autotrophic denitrification. Data collected in previous studies in laboratory experiments and pumping site scale experiments will be used to validate the models. The ultimate objective of this project is to develop a model in which such coupled processes are better understood resulting in best management practices of groundwater.

  11. Cometabolism of trihalomethanes by mixed culture nitrifiers.

    Science.gov (United States)

    Wahman, David G; Henry, Andrea E; Katz, Lynn E; Speitel, Gerald E

    2006-10-01

    Three mixed-culture nitrifier sources degraded low concentrations (25-450 microg/L) of four trihalomethanes (THMs) (trichloromethane (TCM) or chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM) or bromoform) commonly found in treated drinking water. Individual THM rate constants (k1THM) increased with increasing THM bromine-substitution with TBM>DBCM>BDCM>TCM and were comparable to previous studies with the pure culture nitrifier, Nitrosomonas europaea. A decrease in temperature resulted in a decrease in both ammonia and THM degradation rates with ammonia rates affected to a greater extent than THM degradation rates. The significant effect of temperature indicates that seasonal variations in water temperature should be a consideration for technology implementation. Product toxicity, measured by transformation capacity (T(c)), was similar to that observed with N. europaea. Because both rate constants and product toxicities increase with increasing THM bromine-substitution, a water's THM speciation is an important consideration for process implementation during drinking water treatment. Even though a given water is kinetically favored, the resulting THM product toxicity may not allow stable treatment process performance. PMID:16970971

  12. Tracking the dynamics of heterotrophs and nitrifiers in moving-bed biofilm reactors operated at different COD/N ratios.

    Science.gov (United States)

    Bassin, J P; Abbas, B; Vilela, C L S; Kleerebezem, R; Muyzer, G; Rosado, A S; van Loosdrecht, M C M; Dezotti, M

    2015-09-01

    In this study, the impact of COD/N ratio and feeding regime on the dynamics of heterotrophs and nitrifiers in moving-bed biofilm reactors was addressed. Based on DGGE analysis of 16S rRNA genes, the influent COD was found to be the main factor determining the overall bacterial diversity. The amoA-gene-based analysis suggested that the dynamic behavior of the substrate in continuous and pulse-feeding reactors influenced the selection of specific ammonium-oxidizing bacteria (AOB) strains. Furthermore, AOB diversity was directly related to the applied COD/N ratio and ammonium-nitrogen load. Maximum specific ammonium oxidation rates observed under non-substrate-limiting conditions were observed to be proportional to the fraction of nitrifiers within the bacterial community. FISH analysis revealed that Nitrosomonas genus dominated the AOB community in all reactors. Moreover, Nitrospira was found to be the only nitrite-oxidizing bacteria (NOB) in the fully autotrophic system, whereas Nitrobacter represented the dominant NOB genus in the organic carbon-fed reactors. PMID:26025351

  13. 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.

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

    Science.gov (United States)

    Lu, Huijie; Xue, Zheng; Saikaly, Pascal; Nunes, Suzana P; Bluver, Ted R; Liu, Wen-Tso

    2016-01-01

    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.

  15. An evaluation of autotrophic microbes for the removal of carbon dioxide from combustion gas streams

    Energy Technology Data Exchange (ETDEWEB)

    Apel, W.A.; Walton, M.R.; Dugan, P.R. (EG G Idaho, Inc., Idaho Falls, ID (United States). Center for Biological Processing Technology)

    1994-11-01

    Carbon dioxide is a greenhouse gas that is believed to be a major contributor to global warming. Studies have shown that significant amounts of CO[sub 2] are released into the atmosphere as a result of fossil fuels combustion. Therefore, considerable interest exists in effective and economical technologies for the removal of CO[sub 2] from fossil fuel combustion gas streams. This work evaluated the use of autotrophic microbes for the removal of CO[sub 2] from coal fired power plant combustion gas streams. The CO[sub 2] removal rates of the following autotrophic microbes were determined: [ital Chlorella pyrenoidosa], [ital Euglena gracilis], [ital Thiobacillus ferrooxidans], [ital Aphanocapsa delicatissima], [ital Isochrysis galbana], [ital Phaodactylum tricornutum], [ital Navicula tripunctata schizonemoids], [ital Gomphonema parvulum], [ital Surirella ovata ovata], and four algal consortia. Of those tested, [ital Chlorella pyrenoidosa] exhibited the highest removal rate with 2.6 g CO[sub 2] per day per g dry weight of biomass being removed under optimized conditions. Extrapolation of these data indicated that to remove CO[sub 2] from the combustion gases of a coal fired power plant burning 2.4 x 10[sup 4] metric tons of coal per day would require a bioreactor 386 km[sup 2] x 1m deep and would result in the production of 2.13 x 10[sup 5] metric tons (wet weight) of biomass per day. Based on these calculations, it was concluded that autotrophic CO[sub 2] removal would not be feasible at most locations, and as a result, alternate technologies for CO[sub 2] removal should be explored. 14 refs., 7 figs., 2 tabs.

  16. Discrepant membrane fouling of partial nitrification and anammox membrane bioreactor operated at the same nitrogen loading rate.

    Science.gov (United States)

    Niu, Zhao; Zhang, Zuotao; Liu, Sitong; Miyoshi, Taro; Matsuyama, Hideo; Ni, Jinren

    2016-08-01

    In this study, two times more serious membrane fouling was found in anammox membrane bioreactor, compared to partial nitrification membrane bioreactor (PN-MBR) operated at the same nitrogen loading rate. By protein, polysaccharide, amino acids and functional groups analysis, it was found that the discrepancy in membrane fouling was virtually due to the difference in microbial products of nitrifiers and anammox bacteria. Protein and polysaccharide were main foulants on membrane surface; meanwhile theirs content and ratio in the EPS, supernatant and membrane surface were significantly different in PN-MBR and anammox-MBR. The anammox metabolism products contained much more hydrophobic organics, hydrophobic amino acids, and hydrophobic functional groups than nitrifiers. A mass of anammox bacteria as well as hydrophobic metabolism products deposited on the hydrophobic membrane surface and formed serious fouling. In further, hydrophilic modification is more urgently needed to mitigate membrane fouling when running anammox-MBR, than PN-MBR. PMID:27209455

  17. 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.

  18. Influence of biofilm thickness on micropollutants removal in nitrifying MBBRs

    DEFF Research Database (Denmark)

    Torresi, Elena; Andersen, Henrik Rasmus; Smets, Barth F.;

    The removal of pharmaceuticals was investigated in nitrifying Moving Bed Biofilm Reactors (MBBRs) containing carriers with different biofilm thicknesses. The biofilm with the thinnest thickness was found to have the highest nitrification and biotransformation rate for some key pharmaceuticals...

  19. Performance and Biofilm Activity of Nitrifying Biofilters Removing Trihalomethanes

    Science.gov (United States)

    Nitrifying biofilters seeded with three different mixed-culture sources degraded trichloromethane (TCM) and dibromochloromethane (DBCM). In addition, resuspended biofilm degraded TCM, bromododichloromethane (BDCM), DBCM, and tribromomethane (TBM) in backwash batch kinetic tests,...

  20. Monochloramine Cometabolism by Nitrifying Biofilm Relevant to Drinking Water

    Science.gov (United States)

    Recently, biological monochloramine removal (i.e., cometabolism) by a pure culture ammonia–oxidizing bacteria, Nitrosomonas europaea, and a nitrifying mixed–culture have been shown to increase monochloramine demand. Although important, these previous suspended cultur...

  1. p-Cresol mineralization by a nitrifying consortium

    International Nuclear Information System (INIS)

    Nitrification and denitrification processes are considered economically feasible technologies for nitrogen removal from wastewater. Knowledge of the toxic or inhibitory effects of cresols on the nitrifying respiratory process is still insufficient. The aim of this study was to evaluate the kinetic behavior and oxidizing ability of a nitrifying consortium exposed to p-cresol in batch cultures. Biotransformation of p-cresol was investigated by identifying the different intermediates formed. (Author)

  2. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    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.

  3. In Situ Identification and Stratification of Monochloramine Inhibition Effects on Nitrifying Biofilms as Determined by the Use of Microelectrodes

    Science.gov (United States)

    The nitrifying biofilm grown in an annular biofilm reactor and the microbial deactivation achieved after monochloramine treatment were investigated using microelectrodes. The nitrifying biofilm ammonium microprofile was measured and the effect of monochloramine on nitrifying bio...

  4. NASA Bioreactor Demonstration System

    Science.gov (United States)

    2002-01-01

    Leland W. K. Chung (left), Director, Molecular Urology Therapeutics Program at the Winship Cancer Institute at Emory University, is principal investigator for the NASA bioreactor demonstration system (BDS-05). With him is Dr. Jun Shu, an assistant professor of Orthopedics Surgery from Kuming Medical University China. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: Emory University.

  5. Enumeration and activity of nitrifying bacteria in zeoponic substrates

    Science.gov (United States)

    McGilloway, Robyn Leigh

    Regenerative life-support systems are needed for long-term space missions. One component of a proposed life-support system is the use of zeoponic growth substrates, which slowly release NH4 into 'soil' solution for the production of plants. Nitrifying bacteria that convert NH4 to NO3 are among the important microbial components of these systems. Some evidence suggests that a balance between NH4 and NO3 is desirable in promoting plant growth and seed development. Therefore, enumeration of nitrifying bacteria and evaluation of the kinetics of nitrification in zeoponic substrates warrants investigation. A method for rapid detection and enumeration of a commercial inoculum of nitrifying bacteria in a zeoponic substrate was developed using a most probable number (MPN)-polymerase chain reaction (PCR) approach, and a TaqMan probe-based assay. The detection limit of the MPN-PCR methodology was 2,000 cells per assay. Detection sensitivity for the TaqMan assay was determined to be 60 cells. The quantitative assay demonstrated that the zeoponic substrate was capable of supporting 105 to 107 Nitrobacter cells g-1 substrate. The MPN-PCR method and TaqMan probe-based assay can be effective and rapid approaches to enumerate nitrifying bacteria in zeoponic substrates. Column studies and a growth chamber study were conducted to evaluate the production of NO2 and NO3, and nitrifier populations in zeoponic substrates. The zeoponic substrate provided a readily available source of NH4, and nitrifying bacteria were active in the substrate. Quantities of NH4 oxidized, 10 mug N g-1 h-1, to NO2 and NO3 in inoculated zeoponic substrate were in excess of plant uptake. Acidification as a result of NH4 oxidation resulted in decline of pH to 5.5. The zeoponic substrate showed limited pH buffering capacity. Survival of nitrifying bacteria during periods of desiccation was evaluated, as the zeoponic substrate would likely be stored in an air-dry state between croppings. Substrate was enriched for

  6. Population of Nitrifying Bacteria and Nitrification in Ammonium Saturated Clinoptilolite

    Science.gov (United States)

    McGilloway, R. L.; Weaver, R. W.; Ming, Douglas W.; Gruener, J.

    1999-01-01

    As humans begin to spend longer periods of time in space, plants will be incorporated into life support systems. Ammonium saturated clinoptilolite is one plant growth substrate but a balance between ammonium and nitrate is needed. A laboratory study was conducted to determine effects of nitrifying bacteria on ammonium concentrations and kinetics of nitrification. Columns containing clinoptilolite substrate amended with nitrifying bacteria obtained from soil enrichment were analyzed weekly for a 90 day period. The enrichment culture initially contained 1 x 10(exp 5) ammonium oxidizing bacteria and 1 x 10(exp 2) nitrite oxidizing bacteria per gram of substrate. Populations of ammonium oxidizing bacteria increased to 1 x 10(exp 6) and nitrite oxidizing bacteria increased to 1 x 10(exp 3) per gram of substrate. The nitrification rate was approximately 0.25mg NO3(-)-N/kg.hr. Experiments were also conducted to enumerate nitrifying bacteria in a clinoptilolite substrate used to grow wheat (Triticum aestivum L.). Seventy days following the initial inoculation with an unknown number of commercial nitrifying bacteria, 1 x 10(exp 5) ammonium oxidizing bacteria per gram of substrate were present. The number of nitrite oxidizing bacteria was between 1 x 10(exp 3) to 10(exp 4) per gram of substrate as measured by the most probable number method. Nitrification rates were approximately 0.20mg NO3(-)-N/kg.hr. Clinoptilolite readily exchanged sufficient concentrations of ammonium to support nitrifying bacteria and they survived well in this medium.

  7. 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.).

  8. Nitrogen removal in the bioreactor landfill system with intermittent aeration at the top of landfilled waste

    Energy Technology Data Exchange (ETDEWEB)

    He Ruo [College of Environment and Resource, Zhejiang University, Hangzhou 310029 (China)]. E-mail: heruo@zju.edu.cn; Shen Dongsheng [College of Environment and Resource, Zhejiang University, Hangzhou 310029 (China)

    2006-08-25

    High ammonia concentration of recycled landfill leachate makes it very difficult to treat. In this work, a vertical aerobic/anoxic/anaerobic lab-scale bioreactor landfill system, which was constructed by intermittent aeration at the top of landfilled waste, as a bioreactor for in situ nitrogen removal was investigated during waste stabilization. Intermittent aeration at the top of landfilled waste might stimulate the growth of nitrifying bacteria and denitrifying bacteria in the top and middle layers of waste. The nitrifying bacteria population for the landfill bioreactor with intermittent aeration system reached between10{sup 6} and 10{sup 8} cells/dry g waste, although it decreased 2 orders of magnitude on day 30, due to the inhibitory effect of the acid environment and high organic matter in the landfilled waste. The denitrifying bacteria population increased by between 4 and 13 orders of magnitude compared with conventional anaerobic landfilled waste layers. Leachate NO{sub 3} {sup -}-N concentration was very low in both two experimental landfill reactors. After 105 days operation, leachate NH{sub 4} {sup +}-N and TN concentrations for the landfill reactor with intermittent aeration system dropped to 186 and 289 mg/l, respectively, while they were still kept above 1000 mg/l for the landfill reactor without intermittent aerobic system. In addition, there is an increase in the rate of waste stabilization as well as an increase of 12% in the total waste settlement for the landfill reactor with intermittent aeration system.

  9. Bioreactor rotating wall vessel

    Science.gov (United States)

    2001-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells.

  10. Enhanced aerobic nitrifying granulation by static magnetic field.

    Science.gov (United States)

    Wang, Xin-Hua; Diao, Mu-He; Yang, Ying; Shi, Yi-Jing; Gao, Ming-Ming; Wang, Shu-Guang

    2012-04-01

    One of the main challenging issues for aerobic nitrifying granules in treating high strength ammonia wastewater is the long granulation time required for activated sludge to transform into aerobic granules. The present study provides a novel strategy for enhancing aerobic nitrifying granulation by applying an intensity of 48.0mT static magnetic field. The element analysis showed that the applied magnetic field could promote the accumulation of iron compounds in the sludge. And then the aggregation of iron decreased the full granulation time from 41 to 25days by enhancing the setting properties of granules and stimulating the secretion of extracellular polymeric substances (EPS). Long-term, cycle experiments and fluorescence in-situ hybridization (FISH) analysis proved that an intensity of 48.0mT magnetic field could enhance the activities and growth of nitrite-oxidizing bacteria (NOB). These findings suggest that magnetic field is helpful and reliable for accelerating the aerobic nitrifying granulation.

  11. 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.

    Some species of microbial heterotrophic communities (14C glucose uptake and respiration; viable nad total bacterial numbers) and autotrophic communities (primary production rate, chlorophyll a, phytoplankton cell counts and generic diversity) were...

  12. 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

  13. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  14. 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 ...

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

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem

    intensification in single-stage reactors. Single-stage reactors require biofilms or bioaggregates to provide the complementary redox niches for the aerobic and anaerobic bacteria that are required for nitritation and anaerobic ammonium oxidation (anammox), respectively. The nitritation/anammox process might...... ammonium oxidizing bacteria in systems with size-segregated aggregates were considered to weaken the system robustness. Further assessment of the interaction between aeration regime and architectural evolution of the nitritation/anammox aggregates was carried out on the two systems once they achieved......-segregated community became more redox-stratified with larger aggregates. Increasing the duration of aeration, on the other hand, did not significantly alter the original redox-stratified architecture, but allowed proliferation of unwanted nitrite oxidizing bacteria. The decrease in aeration intensity concomitant...

  16. Autotrophic Biofilters for Oxidation of Nitric Oxide

    Institute of Scientific and Technical Information of China (English)

    陈建孟; 陈浚; LanceHershman; 王家德; DanielP.Y.Chang

    2004-01-01

    Carbon foam—a kind of new engineering material as packing material was adopted in three biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was developed on the surface of carbon foams using nitrite as its only nitric source. The moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize the thickness of the liquid film. The liquid phase nitrification test was conducted to determine the variability and the potential of performance among the three carbon foam biofilters. The investigation showed that during the NO2-—N inlet concentration of 200 g·L-1·min-1 to 800 g·L-1·min-1, the 24PPC (pores per centimeter) carbon foam biofilter had the greatest potential, achieving the NO2-—N removal efficiency of 94% to 98%. The 8PPC and 18PPC carbon foam biofilters achieved the NO2-—N removal efficiency of 15% to 21% and of 30% to 40%, respectively. The potential for this system to remove NO from a gas stream was shown on the basis of a steady removal efficiency of 41% to 50% which was attained for the 24PPC carbon foam biofilter at specified NO inlet concentration of 66.97 mg·m-3 to 267.86mg·m-3 and an empty-bed residence time of 3.5 min.

  17. Bioreactors and bioseparation.

    Science.gov (United States)

    Zhang, Siliang; Cao, Xuejun; Chu, Ju; Qian, Jiangchao; Zhuang, Yingping

    2010-01-01

    Along with the rapid development of life science, great attention has been increasingly given to the biotechnological products of cell cultivation technology. In the course of industrialization, bioreactor and bioproduct separation techniques are the two essential technical platforms. In this chapter, the current situation and development prospects of bioreactor techniques in China are systematically discussed, starting with the elucidation of bioreactor processes and the principle of process optimization. Separation technology for biological products is also briefly introduced.At present, a series of bioreactors made by Chinese enterprises have been widely used for laboratory microbial cultivation, process optimization studies, and large-scale production. In the course of bioprocess optimization studies, the complicated bioprocesses in a bioreactor could be resolved into different reaction processes on three scales, namely genetic, cellular, and bioreactor scales. The structural varieties and nonlinear features of various scales of bioprocess systems was discussed through considering the mutual effects of different scale events, namely material flux, energy flux, and information flux, and the optimization approach for bioprocesses was proposed by taking the analysis of metabolic flux and multiscale consideration as a core strategy.In order to realize such an optimization approach, a bioreactor system based on association analysis of multiscale parameters was elaborated, and process optimization of many biological products were materialized, which resulted in great improvement in production efficiency. In designing and manufacturing large-scale bioreactors, the principle of scaling up a process incorporated with flow field study and physiological features in a bioreactor was suggested according to the criterion for the scale-up of cellular physiological and metabolic traits. The flow field features of a bioreactor were investigated through computational fluid

  18. Bioreactors and bioseparation.

    Science.gov (United States)

    Zhang, Siliang; Cao, Xuejun; Chu, Ju; Qian, Jiangchao; Zhuang, Yingping

    2010-01-01

    Along with the rapid development of life science, great attention has been increasingly given to the biotechnological products of cell cultivation technology. In the course of industrialization, bioreactor and bioproduct separation techniques are the two essential technical platforms. In this chapter, the current situation and development prospects of bioreactor techniques in China are systematically discussed, starting with the elucidation of bioreactor processes and the principle of process optimization. Separation technology for biological products is also briefly introduced.At present, a series of bioreactors made by Chinese enterprises have been widely used for laboratory microbial cultivation, process optimization studies, and large-scale production. In the course of bioprocess optimization studies, the complicated bioprocesses in a bioreactor could be resolved into different reaction processes on three scales, namely genetic, cellular, and bioreactor scales. The structural varieties and nonlinear features of various scales of bioprocess systems was discussed through considering the mutual effects of different scale events, namely material flux, energy flux, and information flux, and the optimization approach for bioprocesses was proposed by taking the analysis of metabolic flux and multiscale consideration as a core strategy.In order to realize such an optimization approach, a bioreactor system based on association analysis of multiscale parameters was elaborated, and process optimization of many biological products were materialized, which resulted in great improvement in production efficiency. In designing and manufacturing large-scale bioreactors, the principle of scaling up a process incorporated with flow field study and physiological features in a bioreactor was suggested according to the criterion for the scale-up of cellular physiological and metabolic traits. The flow field features of a bioreactor were investigated through computational fluid

  19. 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.

  20. NASA Bioreactor Schematic

    Science.gov (United States)

    2001-01-01

    The schematic depicts the major elements and flow patterns inside the NASA Bioreactor system. Waste and fresh medium are contained in plastic bags placed side-by-side so the waste bag fills as the fresh medium bag is depleted. The compliance vessel contains a bladder to accommodate pressure transients that might damage the system. A peristolic pump moves fluid by squeezing the plastic tubing, thus avoiding potential contamination. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  1. NASA Classroom Bioreactor

    Science.gov (United States)

    Scully, Robert

    2004-01-01

    Exploration of space provides a compelling need for cell-based research into the basic mechanisms that underlie the profound changes that occur in terrestrial life that is transitioned to low gravity environments. Toward that end, NASA developed a rotating bioreactor in which cells are cultured while continuously suspended in a cylinder in which the culture medium rotates with the cylinder. The randomization of the gravity vector accomplished by the continuous rotation, in a low shear environment, provides an analog of microgravity. Because cultures grown in bioreactors develop structures and functions that are much closer to those exhibited by native tissue than can be achieved with traditional culture methods, bioreactors have contributed substantially to advancing research in the fields of cancer, diabetes, infectious disease modeling for vaccine production, drug efficacy, and tissue engineering. NASA has developed a Classroom Bioreactor (CB) that is built from parts that are easily obtained and assembled, user-friendly and versatile. It can be easily used in simple school settings to examine the effect cultures of seeds or cells. An educational brief provides assembly instructions and lesson plans that describes activities in science, math and technology that explore free fall, microgravity, orbits, bioreactors, structure-function relationships and the scientific method.

  2. Intrinsic autotrophic biomass yield and productivity in algae: modeling spectral and mixing-rate dependence.

    Science.gov (United States)

    Holland, Alexandra D; Wheeler, Dean R

    2011-05-01

    For non-inhibitory irradiances, the rate of algal biomass synthesis was modeled as the product of the algal autotrophic yield Φ(DW) and the flux of photons absorbed by the culture, as described using Beer-Lambert law. As a contrast to earlier attempts, the use of scatter-corrected extinction coefficients enabled the validation of such approach, which bypasses determination of photosynthesis-irradiance (PI) kinetic parameters. The broad misconception that PI curves, or the equivalent use of specific growth rate expressions independent of the biomass concentration, can be extended to adequately model biomass production under light-limitation is addressed. For inhibitory irradiances, a proposed mechanistic model, based on the photosynthetic units (PSU) concept, allows one to estimate a target speed νT across the photic zone in order to limit the flux of photons per cell to levels averting significant reductions in Φ(DW) . These modeled target speeds, on the order of 5-20 m s(-1) for high outdoor irradiances, call for fundamental changes in reactor design to optimize biomass productivity. The presented analysis enables a straightforward bioreactor parameterization, which, in-turn, guides the establishment of conditions ensuring maximum productivity and complete nutrients consumption. Additionally, solar and fluorescent lighting spectra were used to calculate energy to photon-counts conversion factors.

  3. Cascades of bioreactors.

    NARCIS (Netherlands)

    Gooijer, de C.D.

    1995-01-01

    In this thesis a common phenomenon in bioprocess engineering is described : the execution of a certain bioprocess in more than one bioreactor. Chapter 1, a review, classifies bioprocesses by means of a number of characteristics :i) processes with a variable stoichiometry ,ii) processes with a consta

  4. NASA Bioreactor tissue culture

    Science.gov (United States)

    1998-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  5. Basic bioreactor design.

    NARCIS (Netherlands)

    Riet, van 't K.; Tramper, J.

    1991-01-01

    Based on a graduate course in biochemical engineering, provides the basic knowledge needed for the efficient design of bioreactors and the relevant principles and data for practical process engineering, with an emphasis on enzyme reactors and aerated reactors for microorganisms. Includes exercises.

  6. Enhanced biological nutrient removal by the alliance of a heterotrophic nitrifying strain with a nitrogen removing ecosystem

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Nitrogen removal from synthetic wastewater was investigated in an airlift bioreactor (ALB), augmented with a novel heterotrophic nitrifier Pseudonocardia ammonioxydans H9T under organic carbon to nitrogen ratios (Corg/N) ranging from 0 to 12. Effect of the inoculated strain was also determined on the settling properties and the removal of chemical oxygen demand (COD). Two laboratory scale reactors were set up to achieve a stable nitrifying state under the same physicochemical conditions of hydraulic retention time (HRT), temperature, pH and dissolved oxygen (DO), and operated under the sequencing batch mode. The level of DO was kept at 0.5-1.5 mg/L by periodic stirring and aeration. Each specific Corg/N ratio was continued for duration of 3 weeks. One of the reactors (BR2) was inoculated with P. ammonioxydans H9T periodically at the start of each Corg/N ratio. Sludge volumetric index (SVI) improved with the increasing Corg/N ratio, but no significant difference was detected between the two reactors. BR2 showed higher levels of nitrogen removal with the increasing heterotrophic conditions, and the ammonia removal reached to the level of 82%-88%, up to10% higher than that in the control reactor (BR1) at Corg/N ratios higher than 6; however, the ammonia removal level in experimental reactor was up to 8% lower than that in control reactor at Corg/N ratios lower than 2. The COD removal efficiency progressively increased with the increasing Corg/N ratios in both of the reactors. The COD removal percentage up to peak values of 88%-94% in BR2, up to 11% higher than that in BR1 at Corg/N ratio higher than 4. The peak values of ammonia and COD removal almost coincided with the highest number (18%-27% to total bacterial number) of the exogenous bacterium in the BR2, detected as colony forming units (CFU). Furthermore, the removal of ammonia and COD in BR2 was closely related to the number of the inoculated strain with a coefficient index (R2) up to 0.82 and 0.85 for ammonia

  7. Membrane bioreactor for waste gas treatment.

    OpenAIRE

    Reij, M W

    1997-01-01

    SummaryThis thesis describes the design and testing of a membrane bioreactor (MBR) for removal of organic pollutants from air. In such a bioreactor for biological gas treatment pollutants are degraded by micro-organisms. The membrane bioreactor is an alternative to other types of bioreactors for waste gas treatment, such as compost biofilters and bioscrubbers. Propene was used as a model pollutant to study the membrane bioreactor.A membrane bioreactor for waste gas treatment consists of a gas...

  8. Small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water.

    Science.gov (United States)

    Smith, Richard L; Buckwalter, Seanne P; Repert, Deborah A; Miller, Daniel N

    2005-05-01

    Nitrate removal by hydrogen-coupled denitrification was examined using flow-through, packed-bed bioreactors to develop a small-scale, cost effective system for treating nitrate-contaminated drinking-water supplies. Nitrate removal was accomplished using a Rhodocyclus sp., strain HOD 5, isolated from a sole-source drinking-water aquifer. The autotrophic capacity of the purple non-sulfur photosynthetic bacterium made it particularly adept for this purpose. Initial tests used a commercial bioreactor filled with glass beads and countercurrent, non-sterile flow of an autotrophic, air-saturated, growth medium and hydrogen gas. Complete removal of 2 mM nitrate was achieved for more than 300 days of operation at a 2-h retention time. A low-cost hydrogen generator/bioreactor system was then constructed from readily available materials as a water treatment approach using the Rhodocyclus strain. After initial tests with the growth medium, the constructed system was tested using nitrate-amended drinking water obtained from fractured granite and sandstone aquifers, with moderate and low TDS loads, respectively. Incomplete nitrate removal was evident in both water types, with high-nitrite concentrations in the bioreactor output, due to a pH increase, which inhibited nitrite reduction. This was rectified by including carbon dioxide in the hydrogen stream. Additionally, complete nitrate removal was accomplished with wastewater-impacted surface water, with a concurrent decrease in dissolved organic carbon. The results of this study using three chemically distinct water supplies demonstrate that hydrogen-coupled denitrification can serve as the basis for small-scale remediation and that pilot-scale testing might be the next logical step.

  9. Oscillating Cell Culture Bioreactor

    Science.gov (United States)

    Freed, Lisa E.; Cheng, Mingyu; Moretti, Matteo G.

    2010-01-01

    To better exploit the principles of gas transport and mass transport during the processes of cell seeding of 3D scaffolds and in vitro culture of 3D tissue engineered constructs, the oscillatory cell culture bioreactor provides a flow of cell suspensions and culture media directly through a porous 3D scaffold (during cell seeding) and a 3D construct (during subsequent cultivation) within a highly gas-permeable closed-loop tube. This design is simple, modular, and flexible, and its component parts are easy to assemble and operate, and are inexpensive. Chamber volume can be very low, but can be easily scaled up. This innovation is well suited to work with different biological specimens, particularly with cells having high oxygen requirements and/or shear sensitivity, and different scaffold structures and dimensions. The closed-loop changer is highly gas permeable to allow efficient gas exchange during the cell seeding/culturing process. A porous scaffold, which may be seeded with cells, is fixed by means of a scaffold holder to the chamber wall with scaffold/construct orientation with respect to the chamber determined by the geometry of the scaffold holder. A fluid, with/without biological specimens, is added to the chamber such that all, or most, of the air is displaced (i.e., with or without an enclosed air bubble). Motion is applied to the chamber within a controlled environment (e.g., oscillatory motion within a humidified 37 C incubator). Movement of the chamber induces relative motion of the scaffold/construct with respect to the fluid. In case the fluid is a cell suspension, cells will come into contact with the scaffold and eventually adhere to it. Alternatively, cells can be seeded on scaffolds by gel entrapment prior to bioreactor cultivation. Subsequently, the oscillatory cell culture bioreactor will provide efficient gas exchange (i.e., of oxygen and carbon dioxide, as required for viability of metabolically active cells) and controlled levels of fluid

  10. Low concentrations of PAHs induce tolerance in nitrifying bacteria

    Directory of Open Access Journals (Sweden)

    Fredrik eLindgren

    2015-06-01

    Full Text Available The ability of marine microbes to develop tolerance to polycyclic aromatic hydrocarbons (PAHs was examined in a 90-day experiment. PAH levels in sediment were increased 0.3 and 1.6 times compared to the control sediment. Day 30, 60 and 90 the microbes were re-exposed to PAHs in a short-term toxicity test to detect tolerance, where nitrification and denitrification were used as endpoints. In addition, molecular analysis of the microbial communities was performed to detect possible differences in proportions of nitrifying bacteria compared to total bacterial abundance (amoA/rpoB-ratio between treatments and control. We here show PAH-induced tolerance in nitrifying microbial communities after 60 and 90 days of pre-exposure, as potential nitrification EC10-values were significantly higher in the low treatment (L after 60 days and in both treatments after 90 days compared to control. Tolerance development in denitrification was not detected. Furthermore, the developed tolerance resulted in reduced nitrification efficiency, compared to control. It was also shown that the induced tolerance produced dissimilar amoA/rpoB-ratio between treatments and control, indicating that development of tolerance changed the community composition and that the development time depended on initial exposure. The results from this study have implications for future studies or environmental monitoring programs of long-term oil and PAH-contaminated sites. The possibility for development of tolerance needs to be taken into account and potential nitrification can be used for evaluation of marine microbial health. Furthermore, changed proportions of nitrifying microbes can alter the capacity of ammonium oxidizing in benthic marine sediments.

  11. 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%.

  12. 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...

  13. Design challenges for space bioreactors

    Science.gov (United States)

    Seshan, P. K.; Petersen, G. R.

    1989-01-01

    The design of bioreactors for operation under conditions of microgravity presents problems and challenges. Absence of a significant body force such as gravity can have profound consequences for interfacial phenomena. Marangoni convection can no longer be overlooked. Many speculations on the advantages and benefits of microgravity can be found in the literature. Initial bioreactor research considerations for space applications had little regard for the suitability of the designs for conditions of microgravity. Bioreactors can be classified in terms of their function and type of operation. The complex interaction of parameters leading to optimal design and operation of a bioreactor is illustrated by the JSC mammalian cell culture system. The design of a bioreactor is strongly dependent upon its intended use as a production unit for cell mass and/or biologicals or as a research reactor for the study of cell growth and function. Therefore a variety of bioreactor configurations are presented in rapid summary. Following this, a rationale is presented for not attempting to derive key design parameters such as the oxygen transfer coefficient from ground-based data. A set of themes/objectives for flight experiments to develop the expertise for design of space bioreactors is then proposed for discussion. These experiments, carried out systematically, will provide a database from which engineering tools for space bioreactor design will be derived.

  14. 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.

  15. Sensing in tissue bioreactors

    Science.gov (United States)

    Rolfe, P.

    2006-03-01

    Specialized sensing and measurement instruments are under development to aid the controlled culture of cells in bioreactors for the fabrication of biological tissues. Precisely defined physical and chemical conditions are needed for the correct culture of the many cell-tissue types now being studied, including chondrocytes (cartilage), vascular endothelial cells and smooth muscle cells (blood vessels), fibroblasts, hepatocytes (liver) and receptor neurones. Cell and tissue culture processes are dynamic and therefore, optimal control requires monitoring of the key process variables. Chemical and physical sensing is approached in this paper with the aim of enabling automatic optimal control, based on classical cell growth models, to be achieved. Non-invasive sensing is performed via the bioreactor wall, invasive sensing with probes placed inside the cell culture chamber and indirect monitoring using analysis within a shunt or a sampling chamber. Electroanalytical and photonics-based systems are described. Chemical sensing for gases, ions, metabolites, certain hormones and proteins, is under development. Spectroscopic analysis of the culture medium is used for measurement of glucose and for proteins that are markers of cell biosynthetic behaviour. Optical interrogation of cells and tissues is also investigated for structural analysis based on scatter.

  16. Cells growing in NASA Bioreactor

    Science.gov (United States)

    1998-01-01

    For 5 days on the STS-70 mission, a bioreactor cultivated human colon cancer cells, which grew to 30 times the volume of control specimens grown on Earth. This significant result was reproduced on STS-85 which grew mature structures that more closely match what are found in tumors in humans. Shown here, clusters of cells slowly spin inside a bioreactor. On Earth, the cells continually fall through the buffer medium and never hit bottom. In space, they are naturally suspended. Rotation ensures gentle stirring so waste is removed and fresh nutrient and oxygen are supplied. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  17. Structure, composition, and strength of nitrifying membrane-aerated biofilms

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Smets, Barth F.

    2014-01-01

    Membrane-aerated biofilm reactors (MABRs) are a novel technology based on the growth of biofilms on oxygen-permeable membranes. Hereby, MABRs combine all the advantages of biofilm growth with a more flexible and efficient control of the oxygen load. In the present work, flow cell operation...... to achieve full nitrification revealed a significantly different structure of nitrifying MABR biofilms with respect to its co-diffusion counterparts reported in the literature (up to now assumed to have similar properties). Different levels of shear stress and oxygen loadings during MABR operation also...... affected these biofilm parameters. Furthermore, reactor operation at higher oxygen loads resulted in an increase of the biofilm cohesiveness, which depended on the EPS mass in the biofilms and the type of stress applied (more cohesive against normal than shear stresses). The EPS in the strongest biofilms...

  18. N2O emissions from full-scale nitrifying biofilters.

    Science.gov (United States)

    Bollon, Julien; Filali, Ahlem; Fayolle, Yannick; Guerin, Sabrina; Rocher, Vincent; Gillot, Sylvie

    2016-10-01

    A full-scale nitrifying biofilter was continuously monitored during two measurement periods (September 2014; February 2015) during which both gaseous and liquid N2O fluxes were monitored on-line. The results showed diurnal and seasonal variations of N2O emissions. A statistical model was run to determine the main operational parameters governing N2O emissions. Modification of the distribution between the gas phase and the liquid phase was observed related to the effects of temperature and aeration flow on the volumetric mass transfer coefficient (kLa). With similar nitrification performance values, the N2O emission factor was twice as high during the winter campaign. The increase in N2O emissions in winter was correlated to higher effluent nitrite concentrations and suspected increased biofilm thickness.

  19. N2O emissions from full-scale nitrifying biofilters.

    Science.gov (United States)

    Bollon, Julien; Filali, Ahlem; Fayolle, Yannick; Guerin, Sabrina; Rocher, Vincent; Gillot, Sylvie

    2016-10-01

    A full-scale nitrifying biofilter was continuously monitored during two measurement periods (September 2014; February 2015) during which both gaseous and liquid N2O fluxes were monitored on-line. The results showed diurnal and seasonal variations of N2O emissions. A statistical model was run to determine the main operational parameters governing N2O emissions. Modification of the distribution between the gas phase and the liquid phase was observed related to the effects of temperature and aeration flow on the volumetric mass transfer coefficient (kLa). With similar nitrification performance values, the N2O emission factor was twice as high during the winter campaign. The increase in N2O emissions in winter was correlated to higher effluent nitrite concentrations and suspected increased biofilm thickness. PMID:27318446

  20. Characterization of a marine origin aerobic nitrifying-denitrifying bacterium.

    Science.gov (United States)

    Zheng, Hai-Yan; Liu, Ying; Gao, Xi-Yan; Ai, Guo-Min; Miao, Li-Li; Liu, Zhi-Pei

    2012-07-01

    The bacterial strain F6 was isolated from a biological aerated filter that is used for purifying recirculating water in a marine aquaculture system and was identified as Marinobacter sp. based on the analysis of its 16S rRNA gene sequence. Strain F6 showed efficient aerobic denitrifying ability. One hundred percent of nitrates and 73.10% of nitrites were removed, and the total nitrogen (TN) removal rates reached 50.08% and 33.03% under a high nitrate and nitrite concentration in the medium, respectively. N(2)O and (15)N(2), as revealed by GC-MS and GC-IRMS, were the products of aerobic denitrification. Factors affecting the growth and aerobic denitrifying performance of strain F6 were investigated. The results showed that the optimum aerobic denitrification conditions for strain F6 were the presence of sodium succinate as a carbon source, a C/N ratio of 15, salinity ranging from 32-35 g/L of NaCl, incubation temperature of 30°C, an initial pH of 7.5, and rotation speed of 150 rpm [dissolved oxygen (DO) 6.75 mg/L]. In addition, strain F6 was confirmed to be a heterotrophic nitrifier through its NO(2)(-) generation and 25.96% TN removal when NH(4)(+) was used as the sole N source. Therefore, strain F6, the first reported member of genus Marinobacter with aerobic heterotrophic nitrifying-denitrifying ability, is an excellent candidate for facilitating simultaneous nitrification and denitrification (SND) in industry and aquaculture wastewater. PMID:22578593

  1. Spiral vane bioreactor

    Science.gov (United States)

    Morrison, Dennis R. (Inventor)

    1991-01-01

    A spiral vane bioreactor of a perfusion type is described in which a vertical chamber, intended for use in a microgravity condition, has a central rotating filter assembly and has flexible membranes disposed to rotate annularly about the filter assembly. The flexible members have end portions disposed angularly with respect to one another. A fluid replenishment medium is input from a closed loop liquid system to a completely liquid filled chamber containing microcarrier beads, cells and a fluid medium. Output of spent medium is to the closed loop. In the closed loop, the output and input parameters are sensed by sensors. A manifold permits recharging of the nutrients and pH adjustment. Oxygen is supplied and carbon dioxide and bubbles are removed and the system is monitored and controlled by a microprocessor.

  2. Controlled-Turbulence Bioreactors

    Science.gov (United States)

    Wolf, David A.; Schwartz, Ray; Trinh, Tinh

    1989-01-01

    Two versions of bioreactor vessel provide steady supplies of oxygen and nutrients with little turbulence. Suspends cells in environment needed for sustenance and growth, while inflicting less damage from agitation and bubbling than do propeller-stirred reactors. Gentle environments in new reactors well suited to delicate mammalian cells. One reactor kept human kidney cells alive for as long as 11 days. Cells grow on carrier beads suspended in liquid culture medium that fills cylindrical housing. Rotating vanes - inside vessel but outside filter - gently circulates nutrient medium. Vessel stationary; magnetic clutch drives filter cylinder and vanes. Another reactor creates even less turbulence. Oxygen-permeable tubing wrapped around rod extending along central axis. Small external pump feeds oxygen to tubing through rotary coupling, and oxygen diffuses into liquid medium.

  3. Pyrosequencing Analysis of Bench-Scale Nitrifying BiofiltersRemoving Trihalomethanes

    Science.gov (United States)

    The bacterial biofilm communities in four nitrifying biofilters degrading regulated drinking water trihalomethanes were characterized by 454 pyrosequencing. The three most abundant phylotypes based on total diversity were Nitrosomonas (70%), Nitrobacter (14%), and Chitinophagace...

  4. Bioreactor Mass Transport Studies

    Science.gov (United States)

    Kleis, Stanley J.; Begley, Cynthia M.

    1997-01-01

    The objectives of the proposed research efforts were to develop both a simulation tool and a series of experiments to provide a quantitative assessment of mass transport in the NASA rotating wall perfused vessel (RWPV) bioreactor to be flown on EDU#2. This effort consisted of a literature review of bioreactor mass transport studies, the extension of an existing scalar transport computer simulation to include production and utilization of the scalar, and the evaluation of experimental techniques for determining mass transport in these vessels. Since mass transport at the cell surface is determined primarily by the relative motion of the cell assemblage and the surrounding fluid, a detailed assessment of the relative motion was conducted. Results of the simulations of the motion of spheres in the RWPV under microgravity conditions are compared with flight data from EDU#1 flown on STS-70. The mass transport across the cell membrane depends upon the environment, the cell type, and the biological state of the cell. Results from a literature review of cell requirements of several scalars are presented. As a first approximation, a model with a uniform spatial distribution of utilization or production was developed and results from these simulations are presented. There were two candidate processes considered for the experimental mass transport evaluations. The first was to measure the dissolution rate of solid or gel beads. The second was to measure the induced fluorescence of beads as a stimulant (for example hydrogen peroxide) is infused into the vessel. Either technique would use video taped images of the process for recording the quantitative results. Results of preliminary tests of these techniques are discussed.

  5. Characterization of effluent water qualities from satellite membrane bioreactor facilities.

    Science.gov (United States)

    Hirani, Zakir M; Bukhari, Zia; Oppenheimer, Joan; Jjemba, Patrick; LeChevallier, Mark W; Jacangelo, Joseph G

    2013-09-15

    Membrane bioreactors (MBRs) are often a preferred treatment technology for satellite water recycling facilities since they produce consistent effluent water quality with a small footprint and require little or no supervision. While the water quality produced from centralized MBRs has been widely reported, there is no study in the literature addressing the effluent quality from a broad range of satellite facilities. Thus, a study was conducted to characterize effluent water qualities produced by satellite MBRs with respect to organic, inorganic, physical and microbial parameters. Results from sampling 38 satellite MBR facilities across the U.S. demonstrated that 90% of these facilities produced nitrified (NH4-N <0.4 mg/L-N) effluents that have low organic carbon (TOC <8.1 mg/L), turbidities of <0.7 NTU, total coliform bacterial concentrations <100 CFU/100 mL and indigenous MS-2 bacteriophage concentrations <21 PFU/100 mL. Multiple sampling events from selected satellite facilities demonstrated process capability to consistently produce effluent with low concentrations of ammonia, TOC and turbidity. UV-254 transmittance values varied substantially during multiple sampling events indicating a need for attention in designing downstream UV disinfection systems. Although enteroviruses, rotaviruses and hepatitis A viruses (HAV) were absent in all samples, adenoviruses were detected in effluents of all nine MBR facilities sampled. The presence of Giardia cysts in filtrate samples of two of nine MBR facilities sampled demonstrated the need for an appropriate disinfection process at these facilities. PMID:23871258

  6. Distribution of nitrifying activity in the Seine River (France) from Paris to the estuary

    OpenAIRE

    Brion, N; Billen, G.; Guézennec, J.; Ficht, A.

    2000-01-01

    The distribution of nitrification has been measured with the H14CO3- incorporation method in the Seine River and its estuary during summer conditions. The Seine River below Paris receives large amounts of ammonium through wastewater discharge. In the river itself, this ammonium is only slowly nitrified, while in the estuary nitrification is rapid and complete. We show that this contrasting behavior is related to the different hydrosedimentary conditions of the two systems, as nitrifying bacte...

  7. [Study on hydrogen autotrophic denitrification of bio-ceramic reactor].

    Science.gov (United States)

    Chen, Dan; Wang, Hong-Yu; Song, Min; Yang, Kai; Liu, Chen

    2013-10-01

    Nitrate wastewater is processed in a bio-ceramic reactor based on hydrogen autotrophic denitrification. The implementation procedure of biological denitrification by hydrogen autotrophic denitrification was investigated. The effects of hydraulic retention time, influent nitrate load, influent pH, temperature and the amount of hydrogen were assessed throughout this trial. The results showed that the removal rate of NO-(3) -N was 94. 54% and 97. 47% when the hydraulic retention time was 24 h and 48 h, respectively. When the hydraulic retention time was in the range of 5-16 h, the removal rate gradually dropped with the shortening of the hydraulic retention time. When the influent NO-(3) -N concentration was low, with the increase in the influent NO-(3) -N concentration, the degradation rate also increased. The denitrification was inhibited when the NO-(3) -N concentration was higher than 110 mg.L-1. Neutral and alkaline environment was more suitable for the reactor. The reactor showed a wide range of temperature adaptation and the optimum temperature of the reactor was from 25 to 30 degrees C. When hydrogen was in short supply, the effect of denitrification was significantly reduced. These results indicated the specificity of hydrogen utilization by the denitrifying bacteria. The effluent nitrite nitrogen concentration was maintained at low levels during the operation.

  8. Laboratory study of nitrification, denitrification and anammox processes in membrane bioreactors considering periodic aeration.

    Science.gov (United States)

    Abbassi, Rouzbeh; Yadav, Asheesh Kumar; Huang, Shan; Jaffé, Peter R

    2014-09-01

    The possibility of using membrane bioreactors (MBRs) in simultaneous nitrification-anammox-denitrification (SNAD) by considering periodic aeration cycles was investigated. Two separate reactors were operated to investigate the effect of different anammox biomass in the presence of nitrifying and denitrifying biomass on the final nitrogen removal efficiency. The results illustrated that the reactor with higher anammox biomass was more robust to oxygen cycling. Around 98% Total Nitrogen (TN) and 83% Total Organic Carbon (TOC) removal efficiencies were observed by applying one hour aeration over a four-hour cycle. Decreasing the aeration time to 30, 15, and 2 min during a four-hour cycle affected the final TN removal efficiencies. However, the effect of decreasing aeration on the TN removal efficiencies in the reactor with higher anammox biomass was much lower compared to the regular reactor. The nitrous oxide (N2O) emission was a function of aeration as well, and was lower in the reactor with higher anammox biomass. The results of q-PCR analysis confirmed the simultaneous co-existence of nitrifiers, anammox, and denitrifiers in both of the reactors. To simulate the TN removal in these reactors as a function of the aeration time, a new model, based on first order reaction kinetics for both denitrification and anammox was developed and yielded a good agreement with the experimental observations.

  9. 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

  10. Wastewater as a source of nitrifying bacteria in river systems: the case of the River Seine downstream from Paris

    OpenAIRE

    Brion, N; Billen, G.

    2000-01-01

    The River Seine downstream from Paris receives large amounts of ammonium (about 200 µmol/l) from treated and untreated wastewater effluents. In such large river systems, due to the slow growth of nitrifying bacteria, the small size of the nitrifying population present in the water column often represents the limiting factor for nitrification of the contaminating ammonium. In this work we demonstrate that discharge of urban effluents can represent an important seeding of nitrifying bacteria, i...

  11. Progress in bioreactors of bioartiifcial livers

    Institute of Scientific and Technical Information of China (English)

    Cheng-Bo Yu; Xiao-Ping Pan; Lan-Juan Li

    2009-01-01

    BACKGROUND: Bioartiifcial liver support systems are becoming an effective therapy for hepatic failure. Bioreactors, as key devices in these systems, can provide a favorable growth and metabolic environment, mass exchange, and immunological isolation as a platform. Currently, stagnancy in bioreactor research is the main factor restricting the development of bioartiifcial liver support systems. DATA SOURCES: A PubMed database search of English-language literature was performed to identify relevant articles using the keywords "bioreactor", "bioartiifcial liver", "hepatocyte", and "liver failure". More than 40 articles related to the bioreactors of bioartiifcial livers were reviewed. RESULTS: Some progress has been made in the improvement of structures, functions, and modiifed macromolecular materials related to bioreactors in recent years. The current data on the improvement of bioreactor conifgurations for bioartiifcial livers or on the potential of the use of certain scaffold materials in bioreactors, combined with the clinical efifcacy and safety evaluation of cultured hepatocytesin vitro, indicate that the AMC (Academic Medical Center) BAL bioreactor and MELS (modular extracorporeal liver support) BAL bioreactor system can partly replace the synthetic and metabolic functions of the liver in phaseⅠ clinical studies. In addition, it has been indicated that the microlfuidic PDMS (polydimethylsiloxane) bioreactor, or SlideBioreactor, and the microfabricated grooved bioreactor are appropriate for hepatocyte culture, which is also promising for bioartiifcial livers. Similarly, modiifed scaffolds can promote the adhesion, growth, and function of hepatocytes, and provide reliable materials for bioreactors.CONCLUSIONS: Bioreactors, as key devices in bioartiifcial livers, play an important role in the therapy for liver failure both now and in the future. Bioreactor conifgurations are indispensable for the development of bioartiifcial livers used for liver

  12. 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

    was 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...

  13. 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;

    2010-01-01

    was 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...

  14. Preliminary Study on Airlift Membran—Bioreactor

    Institute of Scientific and Technical Information of China (English)

    XUNong; XINGWeihong; 等

    2002-01-01

    A new type of membrane bioreactor named “airlift membrane-bioreactor”is discussed.For municipal wastewater reclamation,the preliminary study on airlift membrane-bioreactor shows its good performance such as high flux and lower energy consumption.The airlift membrane-bioreactor is potentially applicable in bioengineering and environmental protection fields.

  15. Tissue grown in NASA Bioreactor

    Science.gov (United States)

    1998-01-01

    Cells from kidneys lose some of their special features in conventional culture but form spheres replete with specialized cell microvilli (hair) and synthesize hormones that may be clinically useful. Ground-based research studies have demonstrated that both normal and neoplastic cells and tissues recreate many of the characteristics in the NASA bioreactor that they display in vivo. Proximal kidney tubule cells that normally have rich apically oriented microvilli with intercellular clefts in the kidney do not form any of these structures in conventional two-dimensional monolayer culture. However, when normal proximal renal tubule cells are cultured in three-dimensions in the bioreactor, both the microvilli and the intercellular clefts form. This is important because, when the morphology is recreated, the function is more likely also to be rejuvenated. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC).

  16. Sensitivity analysis of autotrophic N removal by a granule based bioreactor: Influence of mass transfer versus microbial kinetics

    DEFF Research Database (Denmark)

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

    2012-01-01

    A comprehensive and global sensitivity analysis was conducted under a range of operating conditions. The relative importance of mass transfer resistance versus kinetic parameters was studied and found to depend on the operating regime as follows: Operating under the optimal loading ratio of 1.90 (g......O2/m3/d)/(gN/m3/d), the system was influenced by mass transfer (10% impact on nitrogen removal) and performance was limited by AOB activity (75% impact on nitrogen removal), while operating above, AnAOB activity was limiting (68% impact on nitrogen removal). The negative effect of oxygen mass...

  17. Isolation and Characteristics of New Heterotrophic Nitrifying Bacteria

    Institute of Scientific and Technical Information of China (English)

    SU Jun-feng; MA Fang; WANG Hong-yu; GUO Jing-bo; HOU Ning; LI Wei-guo; WEI Li

    2007-01-01

    The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. When influent Ammonia nitrogen concentration was 42. 78-73. 62 mg/L. The average ammonia nitrogen removal rate was 81,32% from the bio-ceramics reactor. Sodium acetate and ammonium chloride were used as carbon and nitrogen source. The COD removal rates by microorganisms of strain wgy21 and wgy36 were 56.1% and 45.45%, respectively. The TN removal rates by microorganisms of strain wgy21 and wgy36 were 65.85%and 67. 98%, respectively. At the same time, the concentration of ammonium nitrogen was with the removal rates of 75.25% and 84.96%, and it also had the function of producing NO2-N. Sodium acetate and sodium nitrite were used as carbon and nitrogen source. Through the 12days of the aerobic culture, the COD femoral rates by microorganisms of strain wgy21 and wgy36 were 29.25%and 22.08%, respectively. NO2-N concentration decreased slowly. Comparison, similarity of wgy21 and many Acinetobacter sp. ≥99%, similarity of wgy36 and many Acinetobacter sp. ≥99%. Refer to routine physiological-biochemical characteristic determination, further evidences showed that wgy21 and wgy36 belong to Acinetobacter sp.,respectively.

  18. Bioreactor technology for herbal plants

    International Nuclear Information System (INIS)

    Plants have been an important source of medicine for thousands of years and herbs are hot currency in the world today. During the last decade, popularity of alternative medicine increased significantly worldwide with noticeable trend. This in turn accelerated the global trade of herbal raw materials and herbal products and created greater scope for Asian countries that possess the major supply of herbal raw materials within their highly diversified tropical rain forest. As such, advanced bioreactor culture system possesses a great potential for large scale production than the traditional tissue culture system. Bioreactor cultures have many advantages over conventional cultures. Plant cells in bioreactors can grow fast and vigorously in shorter period as the culture conditions in bioreactor such as temperature, pH, concentrations of dissolved oxygen, carbon dioxide and nutrients can be optimised by on-line manipulation. Nutrient uptake can also be enhanced by continuous medium circulation, which ultimately increased cell proliferation rate. Consequently, production period and cost are substantially reduced, product quality is controlled and standardized as well as free of pesticide contamination and production of raw material can be conducted all year round. Taking all these into consideration, current research efforts were focused on varying several parameters such as inoculation density, air flow, medium formulation, PGRs etc. for increased production of cell and organ cultures of high market demand herbal and medicinal plants, particularly Eurycoma longifolia, Panax ginseng and Labisia pumila. At present, the production of cell and organ culture of these medicinal plants have also been applied in airlift bioreactor with different working volumes. It is hope that the investment of research efforts into this advanced bioreactor technology will open up a bright future for the modernization of agriculture and commercialisation of natural product. (author)

  19. Following an Optimal Batch Bioreactor Operations Model

    DEFF Research Database (Denmark)

    Ibarra-Junquera, V.; Jørgensen, Sten Bay; Virgen-Ortíz, J.J.;

    2012-01-01

    The problem of following an optimal batch operation model for a bioreactor in the presence of uncertainties is studied. The optimal batch bioreactor operation model (OBBOM) refers to the bioreactor trajectory for nominal cultivation to be optimal. A multiple-variable dynamic optimization of fed...... as the master system which includes the optimal cultivation trajectory for the feed flow rate and the substrate concentration. The “real” bioreactor, the one with unknown dynamics and perturbations, is considered as the slave system. Finally, the controller is designed such that the real bioreactor...

  20. Effects of Cr(III) and Cr(VI) on nitrification inhibition as determined by SOUR, function-specific gene expression and 16S rRNA sequence analysis of wastewater nitrifying enrichments.

    Science.gov (United States)

    Kapoor, Vikram; Elk, Michael; Li, Xuan; Impellitteri, Christopher A; Santo Domingo, Jorge W

    2016-03-01

    The effect of Cr(III) and Cr(VI) on nitrification was examined with samples from nitrifying enrichment cultures using three different approaches: by measuring substrate (ammonia) specific oxygen uptake rates (SOUR), by using RT-qPCR to quantify the transcripts of functional genes involved in nitrification, and by analysis of 16S rRNA sequences to determine changes in structure and activity of the microbial communities. The nitrifying bioreactor was operated as a continuous reactor with a 24 h hydraulic retention time. The samples were exposed in batch vessels to Cr(III) (10-300 mg/L) and Cr(VI) (1-30 mg/L) for a period of 12 h. There was considerable decrease in SOUR with increasing dosages for both Cr(III) and Cr(VI), however Cr(VI) was more inhibitory than Cr(III). Based on the RT-qPCR data, there was reduction in the transcript levels of amoA and hao for increasing Cr(III) dosage, which corresponded well with the ammonia oxidation activity measured via SOUR. For Cr(VI) exposure, there was comparatively little reduction in amoA expression while hao expression decreased for 1-3 mg/L Cr(VI) and increased at 30 mg/L Cr(VI). While Nitrosomonas spp. were the dominant bacteria in the bioreactor, based on 16S rRNA sequencing, there was a considerable reduction in Nitrosomonas activity upon exposure to 300 mg/L Cr(III). In contrast, a relatively small reduction in activity was observed at 30 mg/L Cr(VI) loading. Our data that suggest that both Cr(III) and Cr(VI) were inhibitory to nitrification at concentrations near the high end of industrial effluent concentrations. PMID:26774300

  1. Influence of water quality on nitrifier regrowth in two full-scale drinking water distribution systems.

    Science.gov (United States)

    Scott, Daniel B; Van Dyke, Michele I; Anderson, William B; Huck, Peter M

    2015-12-01

    The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems. A culture-based presence-absence test confirmed the presence of viable nitrifiers. AOB were usually present in similar or greater numbers than AOA in both systems. As well, AOB showed higher regrowth potential compared with AOA in both systems. Statistically significant correlations were measured between several water quality parameters of relevance to nitrification. Total chlorine was negatively correlated with both nitrifiers and heterotrophic plate count (HPC) bacteria, and ammonia levels were positively correlated with nitrifiers. Of particular importance was the strong correlation between HPC and AOB, which reinforced the usefulness of HPC as an operational parameter to measure general microbiological conditions in distribution systems.

  2. Intensified nitrogen removal in immobilized nitrifier enhanced constructed wetlands with external carbon addition.

    Science.gov (United States)

    Wang, Wei; Ding, Yi; Wang, Yuhui; Song, Xinshan; Ambrose, Richard F; Ullman, Jeffrey L

    2016-10-01

    Nitrogen removal performance response of twelve constructed wetlands (CWs) to immobilized nitrifier pellets and different influent COD/N ratios (chemical oxygen demand: total nitrogen in influent) were investigated via 7-month experiments. Nitrifier was immobilized on a carrier pellet containing 10% polyvinyl alcohol (PVA), 2.0% sodium alginate (SA) and 2.0% calcium chloride (CaCl2). A batch experiment demonstrated that 73% COD and 85% ammonia nitrogen (NH4-N) were degraded using the pellets with immobilized nitrifier cells. In addition, different carbon source supplement strategies were applied to remove the nitrate (NO3-N) transformed from NH4-N. An increase in COD/N ratio led to increasing reduction in NO3-N. Efficient nitrification and denitrification promoted total nitrogen (TN) removal in immobilized nitrifier biofortified constructed wetlands (INB-CWs). The results suggested that immobilized nitrifier pellets combined with high influent COD/N ratios could effectively improve the nitrogen removal performance in CWs. PMID:27396293

  3. Influence of water quality on nitrifier regrowth in two full-scale drinking water distribution systems.

    Science.gov (United States)

    Scott, Daniel B; Van Dyke, Michele I; Anderson, William B; Huck, Peter M

    2015-12-01

    The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems. A culture-based presence-absence test confirmed the presence of viable nitrifiers. AOB were usually present in similar or greater numbers than AOA in both systems. As well, AOB showed higher regrowth potential compared with AOA in both systems. Statistically significant correlations were measured between several water quality parameters of relevance to nitrification. Total chlorine was negatively correlated with both nitrifiers and heterotrophic plate count (HPC) bacteria, and ammonia levels were positively correlated with nitrifiers. Of particular importance was the strong correlation between HPC and AOB, which reinforced the usefulness of HPC as an operational parameter to measure general microbiological conditions in distribution systems. PMID:26518069

  4. Use Alkalinity Monitoring to Optimize Bioreactor Performance.

    Science.gov (United States)

    Jones, Christopher S; Kult, Keegan J

    2016-05-01

    In recent years, the agricultural community has reduced flow of nitrogen from farmed landscapes to stream networks through the use of woodchip denitrification bioreactors. Although deployment of this practice is becoming more common to treat high-nitrate water from agricultural drainage pipes, information about bioreactor management strategies is sparse. This study focuses on the use of water monitoring, and especially the use of alkalinity monitoring, in five Iowa woodchip bioreactors to provide insights into and to help manage bioreactor chemistry in ways that will produce desirable outcomes. Results reported here for the five bioreactors show average annual nitrate load reductions between 50 and 80%, which is acceptable according to established practice standards. Alkalinity data, however, imply that nitrous oxide formation may have regularly occurred in at least three of the bioreactors that are considered to be closed systems. Nitrous oxide measurements of influent and effluent water provide evidence that alkalinity may be an important indicator of bioreactor performance. Bioreactor chemistry can be managed by manipulation of water throughput in ways that produce adequate nitrate removal while preventing undesirable side effects. We conclude that (i) water should be retained for longer periods of time in bioreactors where nitrous oxide formation is indicated, (ii) measuring only nitrate and sulfate concentrations is insufficient for proper bioreactor operation, and (iii) alkalinity monitoring should be implemented into protocols for bioreactor management.

  5. Comparison of mixotrophic to cyclic autotrophic/heterotrophic growth strategies to optimize productivity of Chlorella sorokiniana

    DEFF Research Database (Denmark)

    van Wagenen, Jonathan Myerson; De Francisci, Davide; Angelidaki, Irini

    2015-01-01

    to autotrophic growth. Chlorella sorokiniana was cultivated in medium supplemented with sodium acetate in concentrations equivalent to the volatile fatty acid concentration found in anaerobic digester effluent. Flat-panel photobioreactors were operated using 16:8 light:dark cycles, with different strategies...... for acetate addition. Acetate was added during the light period for the mixotrophic strategy and during the dark one for the cyclic autotrophic/heterotrophic strategy. Autotrophic productivity of up to 0.99 g L−1 day−1 was obtained using the optimal tested dilution rate of 0.031 h−1. The highest mixotrophic...

  6. 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

  7. Pilot-scale nitrogen removal from leachate by ex situ nitrification and in situ denitrification in a landfill bioreactor.

    Science.gov (United States)

    Sun, Faqian; Sun, Bin; Li, Qian; Deng, Xiaoya; Hu, Jian; Wu, Weixiang

    2014-04-01

    A combined process consisting of ex situ nitrification and in situ denitrification in landfill refuse was studied in pilot scale for nitrogen removal from municipal landfill leachate. The results showed that above 80% of partial nitrification ratio and an average COD loading rate of 1.50 kg m(-3) d(-1) were steadily maintained under DO concentrations of 1.0-1.7 mg L(-1) in the aerobic reactor. Quantitative PCR results indicated that nitrite-oxidizing bacteria being sensitive to DO fluctuations lead to partial nitrification when free ammonia inhibition was weak. Nitrified landfill leachate could be denitrified in the landfill bioreactor with maximum total oxidizing nitrogen removal rate of 67.2 g N t(-1) TSwaste d(-1). Clone and sequencing analysis of denitrifying bacterial nirS gene inferred that heterotrophic denitrifier Azoarcus tolulyticu was the primary nitrogen converter in the landfill bioreactor. The obtained results will provide valuable information for optimizing the design and operation of a landfill bioreactor.

  8. Two new disposable bioreactors for plant cell culture: The wave and undertow bioreactor and the slug bubble bioreactor.

    Science.gov (United States)

    Terrier, Bénédicte; Courtois, Didier; Hénault, Nicolas; Cuvier, Arnaud; Bastin, Maryse; Aknin, Aziz; Dubreuil, Julien; Pétiard, Vincent

    2007-04-01

    The present article describes two novel flexible plastic-based disposable bioreactors. The first one, the WU bioreactor, is based on the principle of a wave and undertow mechanism that provides agitation while offering convenient mixing and aeration to the plant cell culture contained within the bioreactor. The second one is a high aspect ratio bubble column bioreactor, where agitation and aeration are achieved through the intermittent generation of large diameter bubbles, "Taylor-like" or "slug bubbles" (SB bioreactor). It allows an easy volume increase from a few liters to larger volumes up to several hundred liters with the use of multiple units. The cultivation of tobacco and soya cells producing isoflavones is described up to 70 and 100 L working volume for the SB bioreactor and WU bioreactor, respectively. The bioreactors being disposable and pre-sterilized before use, cleaning, sterilization, and maintenance operations are strongly reduced or eliminated. Both bioreactors represent efficient and low cost cell culture systems, applicable to various cell cultures at small and medium scale, complementary to traditional stainless-steel bioreactors.

  9. Filtration characteristics in membrane bioreactors

    NARCIS (Netherlands)

    Evenblij, H.

    2006-01-01

    Causes of and remedies for membrane fouling in Membrane Bioreactors for wastewater treatment are only poorly understood and described in scientific literature. A Filtration Characterisation Installation and a measurement protocol were developed with the aim of a) unequivocally determination and quan

  10. Profiling of microbial communities in a bioreactor for treating hydrocarbon-sulfide-containing wastewater

    Institute of Scientific and Technical Information of China (English)

    LIAO Bo; JI Guodong; CHENG Liqiu

    2008-01-01

    A technology of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to profile the structure and dynamic changes of microbial communities in a bioreactor for treating hydrocarbon-sulfide-containing (HSC) wastewater. The results showed that the heterotrophic genus of Acinetobacter and the autotrophic genera of Thiobacillus and Thiomonas could survive well in all of three operating conditions. Some special genera were also observed with changes of micro-ecoenvironment in the reactor, such as the halophilic genus of Nesterenkonia. Further, a new genus was found in the reactor, which was likely to have the ability to degrade sulfide and hydrocarbon at the same time. All of these detected and the new found genera have widely applicable potential in the treatment of HSC wastewater.

  11. Fate of water borne therapeutic agents and associated effects on nitrifying biofilters in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming

    experience is limited. The two main objectives of this Ph.D. project were to 1) investigate the fate of FA in nitrifying aquaculture biofilters, focusing on factors influencing degradation rates, and 2) investigate the fate of HP and PAA in nitrifying aquaculture biofilters and evaluate the effects...... of these agents on biofilter nitrification performance. All experiments were conducted through addition of chemical additives to closed pilot scale recirculating aquaculture systems (RAS) with fixed media submerged biofilters under controlled operating conditions with rainbow trout (Oncorhynchus mykiss......) in a factorial design with true replicates. Biofilter nitrification performances were evaluated by changes in chemical processes, and nitrifying populations were identified by fluorescence in situ hybridisation (FISH) analysis. FA was degraded at a constant rate immediately after addition, and found...

  12. Structure and activity of multiple nitrifying bacterial populations co-existing in a biofilm

    DEFF Research Database (Denmark)

    Gieseke, A.; Friis-Holm, Lotte Bjerrum; Wagner, M.;

    2003-01-01

    ) by free ammonia under HA conditions. Diversity, spatial distribution, and abundance of nitrifying bacteria as analysed by fluorescence in situ hybridization (FISH) revealed six different nitrifying populations with heterogeneous distributions. Nitrosococcus mobilis formed conspicuous microcolonies locally......A biofilm from a nitrifying pilot-scale sequencing batch reactor was investigated for effects of varying process conditions on its microscale activity and structure. Microsensor measurements of oxygen, substrates and products of nitrification were applied under incubation at different ammonium...... and oxygen concentrations which reflected various situations during a treatment cycle. A high net N loss was observed under high ammonium (HA) concentrations in contrast to low ones. Additionally, results indicated inhibition of nitrite-oxidizing bacteria (NOB), but not of ammonia-oxidizing bacteria (AOB...

  13. [Element Sulfur Autotrophic Denitrification Combined Anaerobic Ammonia Oxidation].

    Science.gov (United States)

    Zhou, Jian; Huang, Yong; Liu, Xin; Yuan, Yi; Li Xiang; Wangyan, De-qing; Ding, Liang; Shao, Jing-wei; Zhao, Rong

    2016-03-15

    A novel element sulfur autotrophic denitrification combined anaerobic ammonia oxidation process, reacted in CSTR, was used to investigate the sulfate production and alkalinity consumption during the whole process. The element sulfur dosage was 50 g · L⁻¹. The inoculation volume of ANAMMOX granular sludge was 100 g · L⁻¹. The agitation rate and environment reaction temperature of the CSTR were set to 120 r · min⁻¹ and 35°C ± 0.5°C, respectively. The pH of influent was maintained in range of 8. 0-8. 4. During the start-up stage of sulfur based autotrophic denitrification, the nitrogen removal loading rate could reach 0.56-0.71 kg · (m³ · d) ⁻¹ in the condition of 5.3 h hydrogen retention time and 200 mg · L⁻¹ nitrate nitrogen. After the addition of 60 mg · L⁻¹ ammonia nitrogen, Δn(SO₄²⁻):Δn(NO₃⁻) decreased from 1.21 ± 0.06 to 1.01 ± 0.10, Δ(IC): Δ(NO₃⁻-N) decreased from 0.72 ± 0.1 to 0.51 ± 0.11, and the effluent pH increased from 6.5 to 7.2. During the combined stage, the ammonia concentration of effluent was 10.1-19.2 mg · L⁻¹, and the nitrate-nitrogen removal loading rate could be maintained in range of 0.66-0.88 kg · (m³ · d)⁻¹. The Δn (NH₄⁺): Δn (NO₃⁻) ratio reached 0.43, and the NO₃⁻ removal rate was increased by 60% in the simultaneous ammonia and nitrate removal reaction under the condition of G(T) = 22-64 s⁻¹ and pH = 8.08, while improper conditions reduced the efficiency of simultaneous reaction.

  14. 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

  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. [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.

  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.

  18. 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

  19. Substrate preference, uptake kinetics and bioenergetics in a facultatively autotrophic, thermoacidophilic crenarchaeote.

    Science.gov (United States)

    Urschel, Matthew R; Hamilton, Trinity L; Roden, Eric E; Boyd, Eric S

    2016-05-01

    Facultative autotrophs are abundant components of communities inhabiting geothermal springs. However, the influence of uptake kinetics and energetics on preference for substrates is not well understood in this group of organisms. Here, we report the isolation of a facultatively autotrophic crenarchaeote, strain CP80, from Cinder Pool (CP, 88.7°C, pH 4.0), Yellowstone National Park. The 16S rRNA gene sequence from CP80 is 98.8% identical to that from Thermoproteus uzonensis and is identical to the most abundant sequence identified in CP sediments. Strain CP80 reduces elemental sulfur (S8°) and demonstrates hydrogen (H2)-dependent autotrophic growth. H2-dependent autotrophic activity is suppressed by amendment with formate at a concentration in the range of 20-40 μM, similar to the affinity constant determined for formate utilization. Synthesis of a cell during growth with low concentrations of formate required 0.5 μJ compared to 2.5 μJ during autotrophic growth with H2 These results, coupled to data indicating greater C assimilation efficiency when grown with formate as compared to carbon dioxide, are consistent with preferential use of formate for energetic reasons. Collectively, these results provide new insights into the kinetic and energetic factors that influence the physiology and ecology of facultative autotrophs in high-temperature acidic environments.

  20. PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS

    Science.gov (United States)

    Six bioreactor landfills were analyzed to provide a perspective of current practice and technical issues that differentiate bioreactor landfills from conventional landfills. Five of the bioreactor landfills were anaerobic and one was aerated. In one case, nearly identical cells e...

  1. 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.

  2. Bioreactor design and optimization – a future perspective

    DEFF Research Database (Denmark)

    Gernaey, Krist

    2011-01-01

    Bioreactor design and optimisation are essential in translating the experience gained from lab or pilot scale experiments to efficient production processes in industrial scale bioreactors. This article gives a future perspective on bioreactor design and optimisation, where it is foreseen that tec......Bioreactor design and optimisation are essential in translating the experience gained from lab or pilot scale experiments to efficient production processes in industrial scale bioreactors. This article gives a future perspective on bioreactor design and optimisation, where it is foreseen...

  3. Prostate tumor grown in NASA Bioreactor

    Science.gov (United States)

    2001-01-01

    This prostate cancer construct was grown during NASA-sponsored bioreactor studies on Earth. Cells are attached to a biodegradable plastic lattice that gives them a head start in growth. Prostate tumor cells are to be grown in a NASA-sponsored Bioreactor experiment aboard the STS-107 Research-1 mission in 2002. Dr. Leland Chung of the University of Virginia is the principal investigator. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and the University of Virginia.

  4. Methane production in simulated hybrid bioreactor landfill.

    Science.gov (United States)

    Xu, Qiyong; Jin, Xiao; Ma, Zeyu; Tao, Huchun; Ko, Jae Hac

    2014-09-01

    The aim of this work was to study a hybrid bioreactor landfill technology for landfill methane production from municipal solid waste. Two laboratory-scale columns were operated for about ten months to simulate an anaerobic and a hybrid landfill bioreactor, respectively. Leachate was recirculated into each column but aeration was conducted in the hybrid bioreactor during the first stage. Results showed that leachate pH in the anaerobic bioreactor maintained below 6.5, while in the hybrid bioreactor quickly increased from 5.6 to 7.0 due to the aeration. The temporary aeration resulted in lowering COD and BOD5 in the leachate. The volume of methane collected from the hybrid bioreactor was 400 times greater than that of the anaerobic bioreactor. Also, the methane production rate of the hybrid bioreactor was improved within a short period of time. After about 10 months' operation, the total methane production in the hybrid bioreactor was 212 L (16 L/kgwaste).

  5. Optimizing of Culture Conditionin Horizontal Rotating Bioreactor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionBioreactor is the most important equipment in tissue engineering. It can mimic the micro-environment of cell growth in vitro. At present, horizontal rotating bioreactor is the most advanced equipment for cell culture in the world. 2 Rotating bioreactors2.1 Working principleThere are two kinds of horizontal rotating bioreactor: HARV(high aspect ratio vessel) and RCCS (rotary cell culture system). It is drived by step motor with horizontal rotation, the culture medium and cell is filled between ...

  6. Review of nonconventional bioreactor technology

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C.E.; Mcllwain, M.E.

    1993-09-01

    Biotechnology will significantly affect many industrial sectors in the future. Industrial sectors that will be affected include pharmaceutical, chemical, fuel, agricultural, and environmental remediation. Future research is needed to improve bioprocessing efficiency and cost-effectiveness in order to compete with traditional technologies. This report describes recent advances in bioprocess technologies and bioreactor designs and relates them to problems encountered in many industrial bioprocessing operations. The primary focus is directed towards increasing gas and vapor transfer for enhanced bioprocess kinetics as well as unproved by-product separation and removal. The advantages and disadvantages of various conceptual designs such as hollow-fiber, gas-phase, hyperbaric/hypobaric, and electrochemical bioreactors are also discussed. Specific applications that are intended for improved bioprocesses include coal desulfurization, coal liquefaction, soil bioremediation, biomass conversion to marketable chemicals, biomining, and biohydrometallurgy as well as bioprocessing of gases and vapors.

  7. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  8. Dynamics of the diversity and structure of the overall and nitrifying microbial community in activated sludge along gradient copper exposures.

    Science.gov (United States)

    Ouyang, Fan; Ji, Min; Zhai, Hongyan; Dong, Zhao; Ye, Lin

    2016-08-01

    Diversity and composition of the microbial community, especially the nitrifiers, are essential to the treatment efficiency of wastewater in activated sludge systems. Heavy metals commonly present in the wastewater influent such as Cu can alter the community structure of nitrifiers and lower their activity. However, the dynamics of microbial community along a gradient of metal exposure have largely been unexplored, partially due to the limitations in traditional molecular methods. This study explored the dynamics regarding the diversity and community structures of overall and nitrifying microbial communities in activated sludge under intermittent Cu gradient loadings using Illumina sequencing. We created a new local nitrifying bacterial database for sequence BLAST searches. High Cu loadings (>10.9 mg/L) impoverished microbial diversity and altered the microbial community. Overall, Proteobacteria was the predominant phylum in the activated sludge system, in which Zoogloea, Thauera, and Dechloromonas (genera within the Rhodocyclaceae family of the Beta-proteobacteria class) were the dominant genera in the presence of Cu. The abundance of unclassified bacteria at the phylum level increased substantially with increasing Cu loadings. Nitrosomonas and Nitrospira were the predominant nitrifiers. The nitrifying bacterial community changed through increasing abundance and shifting to Cu-tolerant species to reduce the toxic effects of Cu. Our local nitrifying bacterial database helped to improve the resolution of bacterial identification. Our results provide insights into the dynamics of microbial community in response to various metal concentrations in activated sludge systems and improve our understanding regarding the effect of metals on wastewater treatment efficiency. PMID:27098258

  9. Denitrification using immersed membrane bioreactors

    OpenAIRE

    McAdam, Ewan J.

    2008-01-01

    Nitrate is practically ubiquitous in waters abstracted for municipal potable water production in Europe due to decades of intensive agricultural practice. Ion exchange is principally selected to target abstracted waters with elevated nitrate concentrations. However, the cost associated with disposal of the waste stream has re-ignited interest in destructive rather concentrative technologies. This thesis explores the potential of membrane bioreactor (MBR) technology for the remo...

  10. Distribution of baroduric, psychrotrophic and culturable nitrifying and denitrifying bacteria in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; PradeepRam, A.S.; Nair, S.; Nath, B.N.; Chandramohan, D.

    ) dry weight sediment and formed 0.21 and 4.30% of the total counts. Unusually high number of nitrifiers comprising of 40% of the total bacterial population have been encountered in one of the cores, namely CIB 16. Denitrifying bacterial population...

  11. Influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules.

    Science.gov (United States)

    Song, Zhiwei; Li, Ting; Wang, Qiuxu; Pan, Yu; Li, Lixin

    2015-09-01

    In order to evaluate the influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules, these granules were cultivated with different seed sludge, and the variation of microbial community and dominant bacterial groups that impact the nitrogen removal efficiency of the aerobic nitrifying granules were analyzed and identified using 16s rDNA sequence and denaturing gradient gel electrophoresis (DGGE) profiles. The results presented here demonstrated that the influence of the community structure of seed sludge on the properties of aerobic nitrifying granules was remarkable, and the granules cultivated by activated sludge from a beer wastewater treatment plant showed better performance, with a stable sludge volume index (SVI) value of 20mL/g, high extracellular polymeric substance (EPS) content of 183.3mg/L, high NH4(+)-N removal rate of 89.42% and abundant microbial population with 10 dominant bacterial groups. This indicated that activated sludge with abundant communities is suitable for use as seed sludge in culturing aerobic nitrifying granules. PMID:26354703

  12. Nitrification performance of nitrifying bacteria immobilized in waterborne polyurethane at low ammonia nitrogen concentrations

    Institute of Scientific and Technical Information of China (English)

    Yamei Dong; Zhenjia Zhang; Yongwei Jin; Zhirong Li; Jian Lu

    2011-01-01

    Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen (DO) concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations.The results showed that nitrification was prone to complete with increasing pH, DO and temperature.Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria.Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient.Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1 mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times (HRT).The continuous removal rate remains above 80% even under HRT 30 min.The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.

  13. Transcriptional and physiological responses of nitrifying bacteria to heavy metal inhibition

    Science.gov (United States)

    Heavy metals have been shown to inhibit nitrification, a key process in the removal of nitrogen in wastewater treatment plants. In the present study, the effects of nickel, zinc, lead and cadmium on nitrifying enrichment cultures were studied in batch reactors. The transcriptiona...

  14. 454 pyrosequencing-based characterization of the bacterial consortia in a well established nitrifying reactor.

    Science.gov (United States)

    Ramirez-Vargas, Rocio; Serrano-Silva, Nancy; Navarro-Noya, Yendi E; Alcántara-Hernández, Rocio J; Luna-Guido, Marco; Thalasso, Frederic; Dendooven, Luc

    2015-01-01

    This present study aimed to characterize the bacterial community in a well-established nitrifying reactor by high-throughput sequencing of 16S rRNA amplicons. The laboratory-scale continuous stirred tank reactor has been supplied with ammonium (NH(4)(+)) as sole energy source for over 5 years, while no organic carbon has been added, assembling thus a unique planktonic community with a mean NH(4)(+) removal rate of 86 ± 1.4 mg NH(4)(+)-N/(L d). Results showed a nitrifying community composed of bacteria belonging to Nitrosomonas (relative abundance 11.0%) as the sole ammonia oxidizers (AOB) and Nitrobacter (9.3%) as the sole nitrite oxidizers (NOB). The Alphaproteobacteria (42.3% including Nitrobacter) were the most abundant class within the Proteobacteria (62.8%) followed by the Gammaproteobacteria (9.4%). However, the Betaproteobacteria (excluding AOB) contributed only 0.08%, confirming that Alpha- and Gammaproteobacteria thrived in low-organic-load environments while heterotrophic Betaproteobacteria are not well adapted to these conditions. Bacteroidetes, known to metabolize extracellular polymeric substances produced by nitrifying bacteria and secondary metabolites of the decayed biomass, was the second most abundant phylum (30.8%). It was found that Nitrosomonas and Nitrobacter sustained a broad population of heterotrophs in the reactor dominated by Alpha- and Gammaproteobacteria and Bacteroidetes, in a 1:4 ratio of total nitrifiers to all heterotrophs. PMID:26360760

  15. Bioreactor microbial ecosystems for thiocyanate and cyanide degradation unravelled with genome-resolved metagenomics.

    Science.gov (United States)

    Kantor, Rose S; van Zyl, A Wynand; van Hille, Robert P; Thomas, Brian C; Harrison, Susan T L; Banfield, Jillian F

    2015-12-01

    Gold ore processing uses cyanide (CN(-) ), which often results in large volumes of thiocyanate- (SCN(-) ) contaminated wastewater requiring treatment. Microbial communities can degrade SCN(-) and CN(-) , but little is known about their membership and metabolic potential. Microbial-based remediation strategies will benefit from an ecological understanding of organisms involved in the breakdown of SCN(-) and CN(-) into sulfur, carbon and nitrogen compounds. We performed metagenomic analysis of samples from two laboratory-scale bioreactors used to study SCN(-) and CN(-) degradation. Community analysis revealed the dominance of Thiobacillus spp., whose genomes harbour a previously unreported operon for SCN(-) degradation. Genome-based metabolic predictions suggest that a large portion of each bioreactor community is autotrophic, relying not on molasses in reactor feed but using energy gained from oxidation of sulfur compounds produced during SCN(-) degradation. Heterotrophs, including a bacterium from a previously uncharacterized phylum, compose a smaller portion of the reactor community. Predation by phage and eukaryotes is predicted to affect community dynamics. Genes for ammonium oxidation and denitrification were detected, indicating the potential for nitrogen removal, as required for complete remediation of wastewater. These findings suggest optimization strategies for reactor design, such as improved aerobic/anaerobic partitioning and elimination of organic carbon from reactor feed. PMID:26031303

  16. Bioreactor microbial ecosystems for thiocyanate and cyanide degradation unravelled with genome-resolved metagenomics.

    Science.gov (United States)

    Kantor, Rose S; van Zyl, A Wynand; van Hille, Robert P; Thomas, Brian C; Harrison, Susan T L; Banfield, Jillian F

    2015-12-01

    Gold ore processing uses cyanide (CN(-) ), which often results in large volumes of thiocyanate- (SCN(-) ) contaminated wastewater requiring treatment. Microbial communities can degrade SCN(-) and CN(-) , but little is known about their membership and metabolic potential. Microbial-based remediation strategies will benefit from an ecological understanding of organisms involved in the breakdown of SCN(-) and CN(-) into sulfur, carbon and nitrogen compounds. We performed metagenomic analysis of samples from two laboratory-scale bioreactors used to study SCN(-) and CN(-) degradation. Community analysis revealed the dominance of Thiobacillus spp., whose genomes harbour a previously unreported operon for SCN(-) degradation. Genome-based metabolic predictions suggest that a large portion of each bioreactor community is autotrophic, relying not on molasses in reactor feed but using energy gained from oxidation of sulfur compounds produced during SCN(-) degradation. Heterotrophs, including a bacterium from a previously uncharacterized phylum, compose a smaller portion of the reactor community. Predation by phage and eukaryotes is predicted to affect community dynamics. Genes for ammonium oxidation and denitrification were detected, indicating the potential for nitrogen removal, as required for complete remediation of wastewater. These findings suggest optimization strategies for reactor design, such as improved aerobic/anaerobic partitioning and elimination of organic carbon from reactor feed.

  17. 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

  18. 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

  19. Bioreactors for Plant Embryogenesis and Beyond.

    Science.gov (United States)

    Fei, Liwen; Weathers, Pamela

    2016-01-01

    A variety of different bioreactors have been developed for use in initiating and cultivating somatic embryos. The various designs for embryogenesis and culture are critically evaluated here. Bioreactor optimization and operation methods are also described along with recommendations for use based on desired outcome.

  20. BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY

    Science.gov (United States)

    Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. ...

  1. Effect of different salt adaptation strategies on the microbial diversity, activity, and settling of nitrifying sludge in sequencing batch reactors

    NARCIS (Netherlands)

    Bassin, J.P.; Kleerebezem, R.; Muyzer, G.; Rosado, A.S.; Van Loosdrecht, M.C.M.; Dezotti, M.

    2011-01-01

    The effect of salinity on the activity of nitrifying bacteria, floc characteristics, and microbial community structure accessed by fluorescent in situ hybridization and polymerase chain reaction–denaturing gradient gel electrophoresis techniques was investigated. Two sequencing batch reactors (SRB1

  2. Autotrophic and heterotrophic activity in Arctic first-year sea ice

    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 (H14CO3– and [3H]thymidine incubation) on sea ice cores brought to the laboratory and (2) cores incubated in situ...... in plastic bags with subsequent melting and measurements of changes in total O2 concentrations. The standard incubations showed that the annual succession followed a distinctive pattern, with a low, almost balancing heterotrophic and autotrophic activity during February and March. This period was followed...... March and April, it resulted in a significant net oxygen accumulation in the bag incubations. Integrated over the entire season, the sea ice of Malene Bight was net autotrophic with an annual net carbon fixation of 220 mg C m– 2, reflecting the net result of a sea ice-related gross primary production...

  3. Drivers for the performance of nitrifying organisms and their temporal and spatial interaction in grassland and forest ecosystems

    OpenAIRE

    Stempfhuber, Barbara Hildegard Josefine

    2016-01-01

    The abundance, activity and diversity of nitrifying organisms and the temporal and spatial interaction patterns of key players were investigated. Drivers influencing these response patterns were examined across forest and grassland ecosystems. In summary, dynamic environmental parameters such as land management affect activity and abundance, while rather stable parameters such as soil pH determine the community composition of nitrifiers across ecosystems. By shaping substrate-levels, drivers ...

  4. Inhibition of Nitrifiers and Methanotrophs from an Agricultural Humisol by Allylsulfide and Its Implications for Environmental Studies

    OpenAIRE

    Neufeld, Josh D.; Knowles, Roger

    1999-01-01

    Allylsulfide, an inhibitor of ammonia monooxygenase, was tested to determine its ability to inhibit nitrification and methane oxidation in pure cultures, in agricultural humisol enrichment cultures, and in humisol slurries. We confirmed that allylsulfide is a differential inhibitor of cultures of nitrifiers and methanotrophs at concentrations of 1 and 200 μM, respectively, which result in 50% inhibition. However, although a nitrifying enrichment culture added to sterilized humisol was inhibit...

  5. Diversity, Abundance, and Potential Activity of Nitrifying and Nitrate-Reducing Microbial Assemblages in a Subglacial Ecosystem ▿ †

    OpenAIRE

    Boyd, Eric S.; Lange, Rachel K.; Mitchell, Andrew C.; Havig, Jeff R.; Hamilton, Trinity L.; Lafrenière, Melissa J.; Shock, Everett L.; Peters, John W.; Skidmore, Mark

    2011-01-01

    Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubate...

  6. MELiSSA third compartment: Nitrosomonas europaea and Nitrobacter winogradskyi axenic cultures in bioreactors

    Science.gov (United States)

    Cruvellier, Nelly; Lasseur, Christophe; Poughon, Laurent; Creuly, Catherine; Dussap, Gilles

    Nitrogen is a key element for the life and its balance on Earth is regulated by the nitrogen cycle. This loop includes several steps among which nitrification that permits the transformation of the ammonium into nitrate. The MELiSSA loop is an artificial ecosystem designed for life support systems (LSS). It is based on the carbon and nitrogen cycles and the recycling of the non-edible part of the higher plants and the waste produced by the crew. In this order, all the wastes are collected in the first compartment to degrade them into organic acids and CO2. These compounds are joining the second compartment which is a photoheterotrophic compartment where at the outlet an organic-free medium containing ammonium is produced. This solution will be the substrate of the third compartment where nitrification is done. This compartment has to oxidize the ammonium into nitrate, and this biological reaction needs two steps. In the MELiSSA loop, the nitrification is carried out by two bacteria: Nitrosomonas europaea ATCC® 19718™ which is oxidizing ammonia into nitrite and Nitrobacter winogradskyi ATCC® 25391™ which is producing nitrate from nitrite in the third compartment. These two bacteria are growing in axenic conditions on a fixed bed bioreactor filled with Biostyr® beads. The nitrogen compounds are controlled by Ionic Chromatography and colorimetric titration for each sample. The work presented here deals with the culture of both bacteria in pure cultures and mixed cultures in stirred and aerated bioreactors of different volumes. The first aim of our work is the characterization of the bacteria growth in bioreactors and in the nitrifying fixed-bed column. The experimental results confirm that the growth is slow; the maximal growth rate in suspended cultures is 0.054h-1 for Nitrosomonas europaea and 0.022h-1 for Nitrobacter winogradskyi. Mixed cultures are difficult to control and operate but one could be done for more than 500 hours. The characterization of the

  7. 新型固定化细胞膜反应器脱氮研究%Study on nitrogen removal from wastewater in a new co-immobilized cells membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    曹国民; 赵庆祥; 龚剑丽; 张彤

    2001-01-01

    研究了一种新型的废水生物脱氮反应器,即利用固定化细胞膜将反应器一隔为二,膜的一侧与好氧的氨氮废水接触,另一侧与缺氧的乙醇水溶液(反硝化碳源)接触.固定于膜中的硝化细菌将氨氮氧化成亚硝氮和硝氮,随即被同一膜中的反硝化细菌还原成氮气.硝化细菌和反硝化细菌混合固定于膜内时的氨氧化速率约为硝化细菌单独固定时的2倍.未发现碳源重复利用对脱氮过程产生不利影响.此新型反应器可以稳定运行50天以上.%A new bioreactor (double-chambered bioreactor) for the nitrogen removal from wastewater was described which consisted of a plate membrane containing nitrifying organisms and denitrifying organisms. The one side of the co-immobilized cells membrane was in aerobic contact with wastewater containing ammonia, while the other side of the membrane was in anoxic contact with ethanol solution (carbon sources for denitrification). Nitrifying bacteria oxidized ammonia to nitrite and nitrate in the membrane, and then denitrifying bacteria reduced nitrite and nitrate to nitrogen gas in the same membrane. The co-immobilized nitrifying organisms and denitrifying organisms accelerated the nitrification rate two times faster than the rate of the immobilized nitrifying organisms alone, although the initial densities of nitrifying organisms in the two membranes were the same. The effect of carbon sources reuse on biological nitrogen removal process wasn't found in the experiment. The co-immobilized cells membrane remained stable for a period of more then 50 days.

  8. Tissue grown in space in NASA Bioreactor

    Science.gov (United States)

    1998-01-01

    For 5 days on the STS-70 mission, a bioreactor cultivated human colon cancer cells, such as the culture section shown here, which grew to 30 times the volume of control specimens grown on Earth. This significant result was reproduced on STS-85 which grew mature structures that more closely match what are found in tumors in humans. The two white circles within the tumor are part of a plastic lattice that helped the cells associate. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  9. N2O production dynamics in nitrifying/denitrifying activated sludge under defined environmental conditions

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Jensen, Marlene Mark; Petersen, Morten S.;

    Nitrous oxide (N2O) is a gaseous pollutant emitted as an unwanted product in wastewater treatment plants during the nitrification-denitrification process. Even though the emission capacity of the process with respect to this compound is still under debate, N2O has been identified as an important...... contributor to global warming and the destruction of the ozone layer. The present study makes use of unique datasets collected during controlled batch tests with activated sludge biomass to test and calibrate a pseudo-mechanistic model that predicts N2O production by nitrifying and heterotrophic bacteria....... The proposed model described successfully the observed N2O production dynamics and confirmed that the availability of ammonia, low dissolved oxygen and nitrite accumulation were the main factors triggering N2O production. Nitrifier-denitrification was proposed as the main pathway catalyzing the conversion...

  10. Co-cultivation of microalgae and nitrifiers for higher biomass production and better carbon capture.

    Science.gov (United States)

    Bilanovic, Dragoljub; Holland, Mark; Starosvetsky, Jeanna; Armon, Robert

    2016-11-01

    The aim of this work was to study co-cultivation of nitrifiers with microalgae as a non-intrusive technique for selective removal of oxygen generated by microalgae. Biomass concentration was, at least, 23% higher in mixed-cultures where nitrifiers kept the dissolved oxygen concentration below 9.0μLL(-1) than in control Chlorella vulgaris axenic-cultures where the concentration of dissolved oxygen was higher than 10.0μLL(-1). This approach to eliminating oxygen inhibition of microalgal growth could become the basis for the development of advanced microalgae reactors for removal of CO2 from the atmosphere, and concentrated CO2 streams. CO2 sequestration would become a chemically and geologically safer and environmentally more sound technology provided it uses microalgal, or other biomass, instead of CO2, for carbon storage. PMID:27584904

  11. Co-cultivation of microalgae and nitrifiers for higher biomass production and better carbon capture.

    Science.gov (United States)

    Bilanovic, Dragoljub; Holland, Mark; Starosvetsky, Jeanna; Armon, Robert

    2016-11-01

    The aim of this work was to study co-cultivation of nitrifiers with microalgae as a non-intrusive technique for selective removal of oxygen generated by microalgae. Biomass concentration was, at least, 23% higher in mixed-cultures where nitrifiers kept the dissolved oxygen concentration below 9.0μLL(-1) than in control Chlorella vulgaris axenic-cultures where the concentration of dissolved oxygen was higher than 10.0μLL(-1). This approach to eliminating oxygen inhibition of microalgal growth could become the basis for the development of advanced microalgae reactors for removal of CO2 from the atmosphere, and concentrated CO2 streams. CO2 sequestration would become a chemically and geologically safer and environmentally more sound technology provided it uses microalgal, or other biomass, instead of CO2, for carbon storage.

  12. Enhancing the formation and shear resistance of nitrifying biofilms on membranes by surface modification

    DEFF Research Database (Denmark)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko;

    2009-01-01

    Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG......) chains with two different functional groups (-PEG-NH2 and -PEG-CH3). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed...... similar trends: biofilms on -PEG-NH2 modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface...

  13. Modelling the fate of nitrite in an urbanized river using experimentally obtained nitrifier growth parameters

    OpenAIRE

    Raimonet, Mélanie; Vilmin, Lauriane; Flipo, Nicolas; Rocher, Vincent; Laverman, Anniet M

    2015-01-01

    International audience Maintaining low nitrite concentrations in aquatic systems is a major issue for stakeholders due to nitrite's high toxicity for living species. This study reports on a cost-effective and realistic approach to study nitrite dynamics and improve its modelling in human-impacted river systems. The implementation of different nitrifying biomasses to model riverine communities and waste water treatment plant (WWTP)-related communities enabled us to assess the impact of a ma...

  14. Temporal Dynamics of Active Prokaryotic Nitrifiers and Archaeal Communities from River to Sea

    OpenAIRE

    Hugoni, Mylène; Agogué, Hélène; Taib, Najwa; Domaizon, Isabelle; Moné, Anne; Pierre E Galand; Bronner, Gisèle; Debroas, Didier; Mary, Isabelle

    2015-01-01

    International audience To test if different niches for potential nitrifiers exist in estuarine systems, we assessed by pyrosequencing the diversity of archaeal gene transcript markers for taxonomy (16S ribosomal RNA (rRNA)) during an entire year along a salinity gradient in surface waters of the Charente estuary (Atlantic coast, France). We further investigated the potential for estuarine prokaryotes to oxidize ammonia and hydrolyze urea by quantifying thaumarchaeal amoA and ureC and bacte...

  15. Study of nitrifying sequencing batch reactor in presence of m-Cresol

    International Nuclear Information System (INIS)

    The process of the nitrification has been studied scantly in presence of phenolic compounds such as m-cresol. the aim of this study was evaluate the tolerance of a nitrifying SBR (Sequencing Batch Reactor) to m-cresol and the ability of the sludge to consume this phenolic compound. Nitrification is the process of oxidation of ammonia to nitrite and nitrate by lithoautotrophic ammonia-and nitrite-oxidizing bacteria. (Author)

  16. Study of nitrifying sequencing batch reactor in presence of m-Cresol

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Alvarez, E.; Steed, E.; Ben-youssef, C.; Zepeda, A.

    2009-07-01

    The process of the nitrification has been studied scantly in presence of phenolic compounds such as m-cresol. the aim of this study was evaluate the tolerance of a nitrifying SBR (Sequencing Batch Reactor) to m-cresol and the ability of the sludge to consume this phenolic compound. Nitrification is the process of oxidation of ammonia to nitrite and nitrate by lithoautotrophic ammonia-and nitrite-oxidizing bacteria. (Author)

  17. Culture-independent detection of "TM7" bacteria in a streptomycin-resistant acidophilic nitrifying process

    Science.gov (United States)

    Kurogi, T.; Linh, N. T. T.; Kuroki, T.; Yamada, T.; Hiraishi, A.

    2014-02-01

    Nitrification in biological wastewater treatment processes has been believed for long time to take place under neutral conditions and is inhibited under acidic conditions. However, we previously constructed acidophilic nitrifying sequencing-batch reactors (ANSBRs) being capable of nitrification at bacteria of the candidate phylum "TM7" as the major constituents of the microbial community. In light of the fact that the 16S rRNA of TM7 bacteria has a highly atypical base substitution possibly responsible for resistance to streptomycin at the ribosome level, this study was undertaken to construct streptomycin-resistant acidophilic nitrifying (SRAN) reactors and to demonstrate whether TM7 bacteria are abundant in these reactors. The SRAN reactors were constructed by seeding with nitrifying sludge from an ANSBR and cultivating with ammonium-containing mineral medium (pH 4.0), to which streptomycin at a concentration of 10, 30 and 50 mg L-1 was added. In all reactors, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate in every batch cycle. PCR-aided denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes revealed that some major clones assigned to TM7 bacteria and Gammaproteobacteria were constantly present during the overall period of operation. Fluorescence in situ hybridization (FISH) with specific oligonucleotide probes also showed that TM7 bacteria predominated in all SRAN reactors, accounting for 58% of the total bacterial population on average. Although the biological significance of the TM7 bacteria in the SRAN reactors are unknown, our results suggest that these bacteria are possibly streptomycin-resistant and play some important roles in the acidophilic nitrifying process.

  18. Tubular membrane bioreactors for biotechnological processes.

    Science.gov (United States)

    Wolff, Christoph; Beutel, Sascha; Scheper, Thomas

    2013-02-01

    This article is an overview of bioreactors using tubular membranes such as hollow fibers or ceramic capillaries for cultivation processes. This diverse group of bioreactor is described here in regard to the membrane materials used, operational modes, and configurations. The typical advantages of this kind of system such as environments with low shear stress together with high cell densities and also disadvantages like poor oxygen supply are summed up. As the usage of tubular membrane bioreactors is not restricted to a certain organism, a brief overview of various applications covering nearly all types of cells from prokaryotic to eukaryotic cells is also given here. PMID:23224587

  19. Spatial Experiment Technologies Suitable for Unreturnable Bioreactor

    Science.gov (United States)

    Zhang, Tao; Zheng, Weibo; Tong, Guanghui

    2016-07-01

    The system composition and main function of the bioreactor piggybacked on TZ cargo transport spacecraft are introduced briefly in the paper.The spatial experiment technologies which are suitable for unreturnable bioreactor are described in detail,including multi-channel liquid transportion and management,multi-type animal cells circuit testing,dynamic targets microscopic observation in situ etc..The feasibility and effectiveness of these technologies which will be used in space experiment in bioreactor are verified in tests and experiments on the ground.

  20. Development of Fundamental Technologies for Micro Bioreactors

    Science.gov (United States)

    Sato, Kiichi; Kitamori, Takehiko

    This chapter reviews the development of fundamental technologies required for microchip-based bioreactors utilizing living mammalian cells and pressure driven flow. The most important factor in the bioreactor is the cell culture. For proper cell culturing, continuous medium supply from a microfluidic channel and appropriate modification of the channel surface to accommodate cell attachment is required. Moreover, the medium flow rate should be chosen carefully, because shear stress affects cell activity. The techniques presented here could be applied to the development of micro bioreactors such as microlivers, pigment production by plant cells, and artificial insemination.

  1. Effect of organic carbon on nitrification efficiency and community composition of nitrifying biofilms

    Institute of Scientific and Technical Information of China (English)

    HU Jie; LI Daping; LIU Qiang; TAO Yong; HE Xiaohong; WANG Xiaomei; LI Xudong; GAO Ping

    2009-01-01

    The effects of organic carbon/inorganic nitrogen (C/N) ratio on the nitrification processes and the community shifts of nitrifying biofilms were investigated by kinetic comparison and denaturing gradient gel electrophoresis (DGGE) analysis. The results showed that the nitrification rate decreased with an increasing organic concentration. However, the effect became weak when the carbon concentration reached sufficiently high level. Denitrification was detected after organic carbon was added. The 12 h ammonium removal rate ranged from 85% to 30% at C/N = 0.5, 1, 2, 4, 8 and 16 compare to control (C/N = 0). The loss of nitrogen at C/N = 0.5, 1, 2, 4, (8 and 16 was 31%, 18%, 24%, 65%, 59% and 62% respectively, after 24 h. Sequence analysis of 16S rRNA gene fragments revealed that the dominant populations changed from nitrifying bacteria (Nitrosomonas europaea and Nitrobacter sp.) to denitrifying bacteria (Pseudomonas sp., Acidovorax sp. and Comamonas sp.) with C/N ratio increase. Although at high C/N ratio the denitrifying bacteria were the dominant populations, nitrifying bacteria grew simultaneously. Conrrespondingly, nitrification process coexisted with denitrification.

  2. Influence of nitrifying conditions on the biodegradation and sorption of emerging micropollutants.

    Science.gov (United States)

    Fernandez-Fontaina, E; Omil, F; Lema, J M; Carballa, M

    2012-10-15

    High biodegradation efficiencies of different emerging micropollutants were obtained with nitrifying activated sludge (NAS) working at high nitrogen loading rates (NLR), that boosted the development of biomass with high nitrifying activities (>1 g N-NH(4)(+)/g VSS d). Come-tabolic biodegradation seemed to be responsible for the removal of most compounds due to the action of the ammonium monooxygenase enzyme. NAS showed a different affinity for each compound, probably due to steric hindrance, activation energy limitations or the presence of specific functional groups. Increasing loading rates of micropollutants were removed at shorter hydraulic retention times, although the biodegradation efficiencies of compounds with slow/intermediate kinetics, such as fluoxetine, erythromycin, roxithromycin and trimethoprim, diminished due to kinetic and/or stoichiometric limitations. Solids retention time, always above the minimum to avoid the washout of nitrifiers, did not enhance the biodegradation of any of the selected compounds, with the exception of diclofenac. Regarding sorption, the solid-liquid distribution coefficients (K(d)) obtained in NAS were very similar to those found in conventional activated sludge by other authors. No correlation between K(d) values and any of the operational parameters was found for the selected substances. PMID:22877882

  3. Effect of wastewater COD/N ratio on aerobic nitrifying sludge granulation and microbial population shift

    Institute of Scientific and Technical Information of China (English)

    Lei Wu; Chengyao Peng; Yongzhen Peng; Lingyun Li; Shuying Wang; Yong Ma

    2012-01-01

    The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200 (m/n).Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/(mg MLVSS.hr),respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.

  4. 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.

  5. 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...

  6. 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...

  7. 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

    Membrane-aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration...

  8. 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

  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. Development of Denitrifying and Nitrifying Bacteria and Their Co-occurrence in Newly Created Biofilms in Urban Streams

    Science.gov (United States)

    Vaessen, T. N.; Martí Roca, E.; Pinay, G.; Merbt, S. N.

    2015-12-01

    Biofilms play a pivotal role on nutrient cycling in streams, which ultimately dictates the export of nutrients to downstream ecosystems. The extent to which biofilms influence the concentration of dissolved nutrients, oxygen and pH in the water column may be determined by the composition of the microbial assemblages and their activity. Evidence of biological interactions among bacteria and algae are well documented. However, the development, succession and co-occurence of nitrifying and denitrifying bacteria remain poorly understood. These bacteria play a relevant role on the biogeochemical process associated to N cycling, and their relative abundance can dictate the fate of dissolved inorganic nitrogen in streams. In particular, previous studies indicated that nitrifiers are enhanced in streams receiving inputs from wastewater treatment plant (WWTP) effluents due to both increases in ammonium concentration and inputs of nitrifiers. However, less is known about the development of denitrifiers in receiving streams, although environmental conditions seem to favor it. We conducted an in situ colonization experiment in a stream receiving effluent from a WWTP to examine how this input influences the development and co-occurrence of nitrifying and denitrifying bacteria. We placed artificial substrata at different locations relative to the effluent and sampled them over time to characterize the developed biofilm in terms of bulk measurements (organic matter content and algae) as well as in terms of abundance of nitrifiers and denitrifiers (using qPCR). The results of this study contribute to a better understanding of the temporal dynamics of denitrifiers and nitrifiers in relation to the developed organic matter, dissolved oxygen and pH and the biomass accrual in stream biofilms under the influence of nutrients inputs from WWTP effluent. Ultimately, the results provide insights on the potential role of nitrifiers and denitrifiers on N cycling in WWTP effluent receiving

  11. An innovative membrane bioreactor for methane biohydroxylation.

    Science.gov (United States)

    Pen, N; Soussan, L; Belleville, M-P; Sanchez, J; Charmette, C; Paolucci-Jeanjean, D

    2014-12-01

    In this study, a membrane bioreactor (MBR) was developed for efficient, safe microbial methane hydroxylation with Methylosinus trichosporium OB3b. This innovative MBR, which couples a bioreactor with two gas/liquid macroporous membrane contactors supplying the two gaseous substrates (methane and oxygen) was operated in fed-batch mode. The feasibility and the reproducibility of this new biohydroxylation process were first demonstrated. The mass transfer within this MBR was twice that observed in a batch reactor in similar conditions. The productivity reached with this MBR was 75±25mgmethanol(gdrycell)(-1)h(-1). Compared to the literature, this value is 35times higher than that obtained with the only other fed-batch membrane bioreactor reported, which was run with dense membranes, and is comparable to those obtained with bioreactors fed by bubble-spargers. However, in the latter case, an explosive gas mixture can be formed, a problem that is avoided with the MBR.

  12. In vivo bioreactors for mandibular reconstruction.

    Science.gov (United States)

    Tatara, A M; Wong, M E; Mikos, A G

    2014-12-01

    Large mandibular defects are difficult to reconstruct with good functional and aesthetic outcomes because of the complex geometry of craniofacial bone. While the current gold standard is free tissue flap transfer, this treatment is limited in fidelity by the shape of the harvested tissue and can result in significant donor site morbidity. To address these problems, in vivo bioreactors have been explored as an approach to generate autologous prefabricated tissue flaps. These bioreactors are implanted in an ectopic site in the body, where ossified tissue grows into the bioreactor in predefined geometries and local vessels are recruited to vascularize the developing construct. The prefabricated flap can then be harvested with vessels and transferred to a mandibular defect for optimal reconstruction. The objective of this review article is to introduce the concept of the in vivo bioreactor, describe important preclinical models in the field, summarize the human cases that have been reported through this strategy, and offer future directions for this exciting approach.

  13. 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.

  14. 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.

  15. Energy efficiency in membrane bioreactors.

    Science.gov (United States)

    Barillon, B; Martin Ruel, S; Langlais, C; Lazarova, V

    2013-01-01

    Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters. The aim of this project was to understand how the energy is consumed in MBR facilities and under which operating conditions, in order to finally provide guidelines and recommended practices for optimisation of MBR operation and design to reduce energy consumption and environmental impacts.

  16. Thin film bioreactors in space

    Science.gov (United States)

    Hughes-Fulford, M.; Scheld, H. W.

    1989-01-01

    Studies from the Skylab, SL-3 and D-1 missions have demonstrated that biological organisms grown in microgravity have changes in basic cellular functions such as DNA, mRNA and protein synthesis, cytoskeleton synthesis, glucose utilization, and cellular differentiation. Since microgravity could affect prokaryotic and eukaryotic cells at a subcellular and molecular level, space offers an opportunity to learn more about basic biological systems with one inmportant variable removed. The thin film bioreactor will facilitate the handling of fluids in microgravity, under constant temperature and will allow multiple samples of cells to be grown with variable conditions. Studies on cell cultures grown in microgravity would make it possible to identify and quantify changes in basic biological function in microgravity which are needed to develop new applications of orbital research and future biotechnology.

  17. NASA Bioreactors Advance Disease Treatments

    Science.gov (United States)

    2009-01-01

    The International Space Station (ISS) is falling. This is no threat to the astronauts onboard, however, because falling is part of the ISS staying in orbit. The absence of gravity beyond the Earth s atmosphere is actually an illusion; at the ISS s orbital altitude of approximately 250 miles above the surface, the planet s gravitational pull is only 12-percent weaker than on the ground. Gravity is constantly pulling the ISS back to Earth, but the space station is also constantly traveling at nearly 18,000 miles per hour. This means that, even though the ISS is falling toward Earth, it is moving sideways fast enough to continually miss impacting the planet. The balance between the force of gravity and the ISS s motion creates a stable orbit, and the fact that the ISS and everything in it including the astronauts are falling at an equal rate creates the condition of weightlessness called microgravity. The constant falling of objects in orbit is not only an important principle in space, but it is also a key element of a revolutionary NASA technology here on Earth that may soon help cure medical ailments from heart disease to diabetes. In the mid-1980s, NASA researchers at Johnson Space Center were investigating the effects of long-term microgravity on human tissues. At the time, the Agency s shuttle fleet was grounded following the 1986 Space Shuttle Challenger disaster, and researchers had no access to the microgravity conditions of space. To provide a method for recreating such conditions on Earth, Johnson s David Wolf, Tinh Trinh, and Ray Schwarz developed that same year a horizontal, rotating device called a rotating wall bioreactor that allowed the growth of human cells in simulated weightlessness. Previously, cell cultures on Earth could only be grown two-dimensionally in Petri dishes, because gravity would cause the multiplying cells to sink within their growth medium. These cells do not look or function like real human cells, which grow three-dimensionally in

  18. Colon tumor cells grown in NASA Bioreactor

    Science.gov (United States)

    2001-01-01

    These photos compare the results of colon carcinoma cells grown in a NASA Bioreactor flown on the STS-70 Space Shuttle in 1995 flight and ground control experiments. The cells grown in microgravity (left) have aggregated to form masses that are larger and more similar to tissue found in the body than the cells cultured on the ground (right). The principal investigator is Milburn Jessup of the University of Texas M. D. Anderson Cancer Center. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). Credit: NASA and University of Texas M. D. Anderson Cancer Center.

  19. New bioreactors systems for pharmacological screening

    OpenAIRE

    Vozzi, Federico

    2007-01-01

    Bioreactors, biotechnological devices for in vitro cell cultures with dynamic conditions, have the potential to provide information on local cell behavior and function. The development of bioreactors could lead to a multitude of applications from drug testing and development, tissue engineering and basic research to the identification of new and alternative therapies for many disorders. High quality, reliable, in vitro data also provide a shift in focus from large scale animal testing to the ...

  20. Effect of sludge retention time on sludge characteristics and membrane fouling of membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    OUYANG Ke; LIU Junxin

    2009-01-01

    Three identical membrane bioreactors (MBRs) were operated over 2 years at different sludge retention times (SRT) of 10, 40 d and no sludge withdrawal (NS), respectively, to elucidate and quantify the effect of SRT on the sludge characteristics and membrane fouling. The hydraulic retention times of these MBRs were controlled at 12 h. With increasing SRT, the sludge concentrations in the MBRs increased, whereas the ratio of volatile suspended solid to the total solid decreased, and the size of sludge granule diminished in the meantime. A higher sludge concentration at long SRT could maintain a better organic removal efficiency, and a longer SRT was propitious to the growth of nitrifiers. The performance of these MBRs for the removal of COD and NH4+-N did not change much with different SRTs. However, the bioactivity decreased as SRT increased. The measurements of specific oxygen uptake rates (SOUR) and fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes testified that SOUR and the proportion of the bacteria-specific probe EUB338 in all DAPI-stainable bacteria decreased with increasing SRT. The concentrations of total organic carbon, protein, polysaccharides and soluble extracellular polymeric substance (EPS) in the mixed liquor supernatant decreased too with increasing SRT. The membrane fouling rate was higher at shorter SRT, and the highest fouling rate appeared at a SRT of 10 d. Both the sludge cake layer and gel layer had contribution to the fouling resistance, but the relative contribution of the gel layer decreased as SRT increased.

  1. Kinetics of phenolic and phthalic acid esters biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate.

    Science.gov (United States)

    Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2016-05-01

    The kinetic of phenolic and phthalic acid esters (PAEs) biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate was investigated. Laboratory-scale MBR was fed with mixture of fresh and stabilized landfill leachate containing carbon to nitrogen (C/N) ratio of 10, 6, 3 and operated under different solid retention time (SRT) of 90, 15 and 5 d. Batch experiments using MBR sludge obtained from each steady-state operating condition revealed highest biodegradation rate constant (k) of 0.059-0.092 h(-1) of the phenolic and PAEs compounds at C/N of 6. Heterotrophic bacteria were the major group responsible for biodegradation of compounds whereas the presence of ammonia-oxidizing bacteria (AOB) helped accelerating their removals. Heterotrophic nitrifying bacteria found under high ammonia condition had an important role in enhancing the biodegradation of phenols and PAEs by releasing phenol hydroxylase (PH), esterase (EST) and phthalate dioxygenase (PDO) enzymes and the presence of AOB helped improving biodegradation of phenolic and PAEs compounds through their co-metabolism. PMID:26908045

  2. A new photo-activated sludge system for nitrification by an algal-bacterial consortium in a photo-bioreactor with biomass recycle.

    Science.gov (United States)

    van der Steen, Peter; Rahsilawati, Kuntarini; Rada-Ariza, Angélica M; Lopez-Vazquez, Carlos M; Lens, Piet N L

    2015-01-01

    Wastewater treatment technologies requiring large areas may be less feasible in urbanizing regions of developing countries. Therefore, a new technology, named photo-activated sludge (PAS), was investigated to combine the advantages of regular activated sludge systems with those of algae ponds for the removal of ammonium. The PAS consisted of a mixed photo-bioreactor, continuously fed with BG-11 medium, adjusted to 66 mgN-NH4⁺/l. The reactor volume was 2 l, hydraulic retention time was 24 hours, with a depth of 8 cm, and continuous illumination at the water surface was 66 μmol PAR/m²/s (photosynthetically active radiation). Reactor effluent passed through a settler and settled biomass was returned to the reactor. A well settling biomass developed, that contained both algae and nitrifiers. Effluent contained 10 mgN-NH4⁺/L and 51 mgN-NOx⁻/L. Using a simplified model, the specific algae growth rate was estimated at about 0.62 day⁻¹, which was within the expected range. For nitrifiers (ammonia oxidizers), the specific growth rate was 0.11 day⁻¹, which was lower than reported for regular activated sludge. The in-situ photo-oxygenation process by algae contributed 82% of the oxygen input, whereas oxygen diffusion through the mixed surface provided the remaining 18%. The foreseen energy savings that a PAS system could achieve warrant further investigations with real wastewater. PMID:26204077

  3. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    Directory of Open Access Journals (Sweden)

    Miguel Ramirez

    2014-01-01

    Full Text Available Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2 and nitrous oxide (N2O while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1 was examined for its ability to perform heterotrophic nitrification in the presence of Cu2+ and Ni2+ and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1 mM Cu2+ or 0.5 mM Ni2+ was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1 mM Cu2+ or 0.5 mM Ni2+. The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed.

  4. Advanced microscale bioreactor system: a representative scale-down model for bench-top bioreactors.

    Science.gov (United States)

    Hsu, Wei-Ting; Aulakh, Rigzen P S; Traul, Donald L; Yuk, Inn H

    2012-12-01

    In recent years, several automated scale-down bioreactor systems have been developed to increase efficiency in cell culture process development. ambr™ is an automated workstation that provides individual monitoring and control of culture dissolved oxygen and pH in single-use, stirred-tank bioreactors at a working volume of 10-15 mL. To evaluate the ambr™ system, we compared the performance of four recombinant Chinese hamster ovary cell lines in a fed-batch process in parallel ambr™, 2-L bench-top bioreactors, and shake flasks. Cultures in ambr™ matched 2-L bioreactors in controlling the environment (temperature, dissolved oxygen, and pH) and in culture performance (growth, viability, glucose, lactate, Na(+), osmolality, titer, and product quality). However, cultures in shake flasks did not show comparable performance to the ambr™ and 2-L bioreactors.

  5. Diversity and distribution of amoA-type nitrifying and nirS-type denitrifying microbial communities in the Yangtze River estuary

    OpenAIRE

    Y. Zhang; Xie, X.; Jiao, N.; Hsiao, S. S.-Y.; Kao, S.-J.

    2014-01-01

    Coupled nitrification–denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtro...

  6. Tubular bioreactor and its application; Tubular bioreactor to sono tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Endo, I.; Nagamune, T. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Yuki, K. [Nikka Whisky Distilling Co. Ltd. Tokyo (Japan); Inaba, H. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1994-09-05

    The loop type tubular bioreactor (TBR) was developed where biocatalysts are trapped in the reactor by membrane module. A UF membrane or MF membrane and crossflow filtration were adopted for the membrane module, and the reactor loop was composed of four membrane modules. The reactor was operated at 2-4 m/s in membrane surface velocity and 300-400 kPa in filtration pressure. As the result of the high-density culture of lactic acid bacteria and yeast, a biomass concentration was more than 10 times that in batch culture, suggesting the remarkable enhancement of a production efficiency. As the result of the continuous fermentation of cider, the fast fermentation more than 60 times that in conventional ones was obtained together with the same quality as conventional ones. Such a fast fermentation was probably achieved by yeast suspended in the fermenter of TBR, by yeast hardly affected physico-chemically as compared with immobilized reactors, and by small effect of mass transfer on reaction systems. 4 refs., 6 figs.

  7. Optimizing of Culture Condition in Horizontal Rotating Bioreactor

    Institute of Scientific and Technical Information of China (English)

    Yan-Fang ZHANG; Huai-Qing CHEN; Hua HUANG

    2005-01-01

    @@ 1 Introduction Bioreactor is the most important equipment in tissue engineering. It can mimic the micro-environment of cell growth in vitro. At present, horizontal rotating bioreactor is the most advanced equipment for cell culture in the world.

  8. 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

    to grow quicker autotrophically with methanol, a toxic C1 compound, as the sole substrate. Better growth on different concentrations of methanol and with H2-CO2 indicated the adapted strain had a more efficient autotrophic metabolism and a higher tolerance to solvent. The growth rate on methanol......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...... was 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...

  9. 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.

  10. Completely Autotrophic Nitrogen-removal over Nitrite in Two Types of Reactors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Two lab-scale reactors, susponded-sludge and fluidized-bed, were conducted with the feed of ammonium-rich syntheticwa,tewater devoid of COD. Completely autotrophic nitrogen-removal process was fulfilled in both reactors and the maximum efficiencies of nitrogen removal were achieved, 65% in the suspended-sludge reactor and 73% in the fluidized-bed reactor respectively. Different fromn the steady performance of the fluidized-bed reactor, the suspended-sludge reactor came to deteriorate constantly after a period of stable operation, resulting in almost complete loss of the N-removal ability in the suspending system.Molecular methods such as PCR and FISH were employed for describing the microbial characteristics in two systems. This study suggests that a biofilm system is a suitable configuration for completely autotrophic N-removal with more feasibility and stability than a suspending system.

  11. Nitrogen removal in a single-chamber microbial fuel cell with nitrifying biofilm enriched at the air cathode

    KAUST Repository

    Yan, Hengjing

    2012-05-01

    Nitrogen removal is needed in microbial fuel cells (MFCs) for the treatment of most waste streams. Current designs couple biological denitrification with side-stream or combined nitrification sustained by upstream or direct aeration, which negates some of the energy-saving benefits of MFC technology. To achieve simultaneous nitrification and denitrification, without extra energy input for aeration, the air cathode of a single-chamber MFC was pre-enriched with a nitrifying biofilm. Diethylamine-functionalized polymer (DEA) was used as the Pt catalyst binder on the cathode to improve the differential nitrifying biofilm establishment. With pre-enriched nitrifying biofilm, MFCs with the DEA binder had an ammonia removal efficiency of up to 96.8% and a maximum power density of 900 ± 25 mW/m 2, compared to 90.7% and 945 ± 42 mW/m 2 with a Nafion binder. A control with Nafion that lacked nitrifier pre-enrichment removed less ammonia and had lower power production (54.5% initially, 750 mW/m 2). The nitrifying biofilm MFCs had lower Coulombic efficiencies (up to 27%) than the control reactor (up to 36%). The maximum total nitrogen removal efficiency reached 93.9% for MFCs with the DEA binder. The DEA binder accelerated nitrifier biofilm enrichment on the cathode, and enhanced system stability. These results demonstrated that with proper cathode pre-enrichment it is possible to simultaneously remove organics and ammonia in a single-chamber MFC without supplemental aeration. © 2012 Elsevier Ltd.

  12. Nitrifying and denitrifying bacteria in aerobic granules formed in sequencing batch airlift reactors

    Institute of Scientific and Technical Information of China (English)

    WANG Fang; YANG Fenglin; QI Aijiu

    2007-01-01

    The purpose of this study was to investigate nitrifying bacteria and denitrifying bacteria isolated from aerobic granules.Aerobic granules were formed in an internal-circulate sequencing batch airlift reactor(SBAR)and biodegradation of NH3 -N was analyzed in the reactor.Bacteria were isolated and determined from aerobic granules using selected media.The growth properties and morphology of bacteria colonies were observed by controlling aerobic or anaerobic conditions in the culture medium.It was found that bacteria in aerobic granules were diverse and some of them were facultative aerobes.The diversity of bacteria in aerobic granules was a premise of simultaneous nitrification and denitrification.

  13. Performance of Anammox granular sludge bed reactor started up with nitrifying granular sludge

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ping; LIN Feng-mei; HU Bao-lan; CHEN Jian-song

    2004-01-01

    The anaerobic ammonia oxidation(Anammox) granular sludge bed reactor was started up successfully withnitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammoxgranular sludge with good settling property and high conversion activity. The Anammox reactor worked well with theshortest HRT of 2.43 h. Under the condition that HRT was 6.39 h and influent concentration of ammonia and nitritewas 10 mmol/L, the removal of ammonia and nitrite was 97.17% and 100.00%, respectively. Corresponding

  14. Development of Novel Random Network Theory-Based Approaches to Identify Network Interactions among Nitrifying Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Cindy

    2015-07-17

    The interactions among different microbial populations in a community could play more important roles in determining ecosystem functioning than species numbers and their abundances, but very little is known about such network interactions at a community level. The goal of this project is to develop novel framework approaches and associated software tools to characterize the network interactions in microbial communities based on high throughput, large scale high-throughput metagenomics data and apply these approaches to understand the impacts of environmental changes (e.g., climate change, contamination) on network interactions among different nitrifying populations and associated microbial communities.

  15. 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

  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. 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.

    and to highlight the importance and seasonal dynamics of different viral groups. In addition, we tried to relate such richness to potential autotrophic hosts and the influence of key environmental factors on the dynamics of specific viral communities in Lake.... 1998) but reported to be specific 12 for marine cyanomyoviruses. Hence it is important to re-evaluate the use of such primers specific for marine cyanomyoviruses in studies pertaining to lacustrine environments. Besides, the burst size...

  20. 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

    This work describes the successful coupling of partial nitrification (nitritation) and anaerobic ammonium oxidation in a membrane-aerated biofilm reactor (MABR) with continuous aeration. Controlling the relative surface loadings of oxygen versus ammonium prevented complete nitrite oxidation...... nearest to and AnaerAOB furthest from the membrane. Despite the presence of nitrite-oxidizing bacteria, this work demonstrated that these autotrophic processes can be successfully coupled in an MABR with continuous aeration, achieving the benefits of competitive specific N removal rates...

  1. 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...

  2. 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...

  3. Open source software to control Bioflo bioreactors.

    Directory of Open Access Journals (Sweden)

    David A Burdge

    Full Text Available Bioreactors are designed to support highly controlled environments for growth of tissues, cell cultures or microbial cultures. A variety of bioreactors are commercially available, often including sophisticated software to enhance the functionality of the bioreactor. However, experiments that the bioreactor hardware can support, but that were not envisioned during the software design cannot be performed without developing custom software. In addition, support for third party or custom designed auxiliary hardware is often sparse or absent. This work presents flexible open source freeware for the control of bioreactors of the Bioflo product family. The functionality of the software includes setpoint control, data logging, and protocol execution. Auxiliary hardware can be easily integrated and controlled through an integrated plugin interface without altering existing software. Simple experimental protocols can be entered as a CSV scripting file, and a Python-based protocol execution model is included for more demanding conditional experimental control. The software was designed to be a more flexible and free open source alternative to the commercially available solution. The source code and various auxiliary hardware plugins are publicly available for download from https://github.com/LibourelLab/BiofloSoftware. In addition to the source code, the software was compiled and packaged as a self-installing file for 32 and 64 bit windows operating systems. The compiled software will be able to control a Bioflo system, and will not require the installation of LabVIEW.

  4. Influence of wastewater composition on nutrient removal behaviors in the new anaerobic–anoxic/nitrifying/induced crystallization process

    OpenAIRE

    Shi, Jing; Xiwu LU; Yu, Ran; Gu, Qian; Zhou, Yi

    2013-01-01

    In this study, the new anaerobic–anoxic/nitrifying/induced crystallization (A2N–IC) system was compared with anaerobic-anoxic/nitrifying (A2N) process to investigate nutrient removal performance under different influent COD and ammonia concentrations. Ammonia and COD removal rates were very stable in both processes, which were maintained at 84.9% and 86.6% when the influent ammonia varied from 30 mg L−1 to 45 mg L−1 and COD ranged from 250 mg L−1 to 300 mg L−1. The effluent phosphorus always ...

  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.

  6. 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

  7. A pH-control model for heterotrophic and hydrogen-based autotrophic denitrification.

    Science.gov (United States)

    Tang, Youneng; Zhou, Chen; Ziv-El, Michal; Rittmann, Bruce E

    2011-01-01

    This work presents a model to predict the alkalinity, pH, and Langelier Saturation Index (LSI) in heterotrophic and H(2)-based autotrophic denitrification systems. The model can also be used to estimate the amount of acid, e.g. HCl, added to the influent (method 1) or the pH set point in the reactor (method 2: pH can be maintained stable by CO(2)-sparge using a pH-control loop) to prevent the pH from exceeding the optimal range for denitrification and to prevent precipitation from occurring. The model was tested with two pilot plants carrying out denitrification of groundwater with high hardness: a heterotrophic system using ethanol as the electron donor and an H(2)-based autotrophic system. The measured alkalinity, pH, and LSI were consistent with the model for both systems. This work also quantifies: (1) how the alkalinity and pH in Stage-1 significantly differ from those in Stage-2; (2) how the pH and LSI differ significantly in the two denitrification systems while the alkalinity increase is about the same; and (3) why CO(2) addition is the preferred method for autotrophic system, while HCl addition is the preferred method for the heterotrophic system.

  8. Autotrophic ammonia oxidation at low pH through urea hydrolysis.

    Science.gov (United States)

    Burton, S A; Prosser, J I

    2001-07-01

    Ammonia oxidation in laboratory liquid batch cultures of autotrophic ammonia oxidizers rarely occurs at pH values less than 7, due to ionization of ammonia and the requirement for ammonium transport rather than diffusion of ammonia. Nevertheless, there is strong evidence for autotrophic nitrification in acid soils, which may be carried out by ammonia oxidizers capable of using urea as a source of ammonia. To determine the mechanism of urea-linked ammonia oxidation, a ureolytic autotrophic ammonia oxidizer, Nitrosospira sp. strain NPAV, was grown in liquid batch culture at a range of pH values with either ammonium or urea as the sole nitrogen source. Growth and nitrite production from ammonium did not occur at pH values below 7. Growth on urea occurred at pH values in the range 4 to 7.5 but ceased when urea hydrolysis was complete, even though ammonia, released during urea hydrolysis, remained in the medium. The results support a mechanism whereby urea enters the cells by diffusion and intracellular urea hydrolysis and ammonia oxidation occur independently of extracellular pH in the range 4 to 7.5. A proportion of the ammonia produced during this process diffuses from the cell and is not subsequently available for growth if the extracellular pH is less than 7. Ureolysis therefore provides a mechanism for nitrification in acid soils, but a proportion of the ammonium produced is likely to be released from the cell and may be used by other soil organisms.

  9. First flowering hybrid between autotrophic and mycoheterotrophic plant species: breakthrough in molecular biology of mycoheterotrophy.

    Science.gov (United States)

    Ogura-Tsujita, Yuki; Miyoshi, Kazumitsu; Tsutsumi, Chie; Yukawa, Tomohisa

    2014-03-01

    Among land plants, which generally exhibit autotrophy through photosynthesis, about 880 species are mycoheterotrophs, dependent on mycorrhizal fungi for their carbon supply. Shifts in nutritional mode from autotrophy to mycoheterotrophy are usually accompanied by evolution of various combinations of characters related to structure and physiology, e.g., loss of foliage leaves and roots, reduction in seed size, degradation of plastid genome, and changes in mycorrhizal association and pollination strategy. However, the patterns and processes involved in such alterations are generally unknown. Hybrids between autotrophic and mycoheterotrophic plants may provide a breakthrough in molecular studies on the evolution of mycoheterotrophy. We have produced the first hybrid between autotrophic and mycoheterotrophic plant species using the orchid group Cymbidium. The autotrophic Cymbidium ensifolium subsp. haematodes and mycoheterotrophic C. macrorhizon were artificially pollinated, and aseptic germination of the hybrid seeds obtained was promoted by sonication. In vitro flowering was observed five years after seed sowing. Development of foliage leaves, an important character for photosynthesis, segregated in the first generation; that is, some individuals only developed scale leaves on the rhizome and flowering stems. However, all of the flowering plants formed roots, which is identical to the maternal parent.

  10. Hydrodynamics research of wastewater treatment bioreactors

    Institute of Scientific and Technical Information of China (English)

    REN Nan-qi; ZHANG Bing; ZHOU Xue-fei

    2009-01-01

    To optimize the design and improve the performance of wastewater treatment bioreactors, the review concerning the hydrodynamics explored by theoretical equations, process experiments, modeling of the hydrody-namics and flow field measurement is presented. Results of different kinds of experiments show that the hydro-dynamic characteristics can affect sludge characteristics, mass transfer and reactor performance significantly. A-long with the development of theoretical equations, turbulence models including large eddy simulation models and Reynolds-averaged Navier-Stokes (RANS) models are widely used at present. Standard and modified k-ε models are the most widely used eddy viscosity turbulence models for simulating flows in bioreactors. Numericalsimulation of hydrodynamics is proved to be efficient for optimizing design and operation. The development of measurement techniques with high accuracy and low intrusion enables the flow filed in the bioreactors to be transparent. Integration of both numerical simulation and experimental measurement can describe the hydrody-namics very well.

  11. Evolution of Bioreactors for Extracorporeal Liver Support

    Directory of Open Access Journals (Sweden)

    Vilkova Е.V.

    2014-03-01

    Full Text Available The development of effective extracorporeal liver support systems in acute and chronic hepatic failure for transplantology purposes and in toxic injuries is a promising direction in modern biomedical studies. Widely used techniques are based on physicochemical interactions of biological molecules, and able to perform a detoxification function only (hemodialysis, hemofiltration, hemodiafiltration, sorption, albumin dialysis, plasmapheresis. However, support systems combining both blood/plasma perfusion and cellular technologies to maintain metabolic, synthetic and regulatory hepatic functions — “artificial liver” systems — are being extensively developed in recent decades. The review describes the main types of cell lines cultured to occupy bioreactors, various technological concepts for bioreactor design (dynamic, static, scaffold-carriers as part of bioreactors (structure, biochemical composition. The study gives metabolic characteristics of a cellular component of “bioartificial liver”: nourishment, oxygen saturation. Various types of existing extracorporeal support systems, their evolution, and preclinical and clinical test results are presented.

  12. Assessment of bacterial community structure in nitrifying biofilm under inorganic carbon-sufficient and -limited conditions.

    Science.gov (United States)

    Bae, Hyokwan; Chung, Yun-Chul; Yang, Heejeong; Lee, Changsoo; Aryapratama, Rio; Yoo, Young J; Lee, Seockheon

    2015-01-01

    In this work, nitrification and changes in the composition of the total bacterial community under inorganic carbon (IC)-limited conditions, in a nitrifying moving bed biofilm reactor, was investigated. A culture-independent analysis of cloning and sequencing based on the 16S rRNA gene was applied to quantify the bacterial diversity and to determine bacterial taxonomic assignment. IC concentrations had significant effects on the stability of ammonia-oxidation as indicated by the reduction of the nitrogen conversion rate with high NH4(+)-N loadings. The predominance of Nitrosomonas europaea was maintained in spite of changes in the IC concentration. In contrast, heterotrophic bacterial species contributed to a high bacterial diversity, and to a dynamic shift in the bacterial community structure, under IC-limited conditions. In this study, individual functions of heterotrophic bacteria were estimated based on taxonomic information. Possible key roles of coexisting heterotrophic bacteria are the assimilation of organic compounds of extracellular polymeric substances produced by nitrifiers, and biofilm formation by providing a filamentous structure and aggregation properties.

  13. Temporal Dynamics of Active Prokaryotic Nitrifiers and Archaeal Communities from River to Sea.

    Science.gov (United States)

    Hugoni, Mylène; Agogué, Hélène; Taib, Najwa; Domaizon, Isabelle; Moné, Anne; Galand, Pierre E; Bronner, Gisèle; Debroas, Didier; Mary, Isabelle

    2015-08-01

    To test if different niches for potential nitrifiers exist in estuarine systems, we assessed by pyrosequencing the diversity of archaeal gene transcript markers for taxonomy (16S ribosomal RNA (rRNA)) during an entire year along a salinity gradient in surface waters of the Charente estuary (Atlantic coast, France). We further investigated the potential for estuarine prokaryotes to oxidize ammonia and hydrolyze urea by quantifying thaumarchaeal amoA and ureC and bacterial amoA transcripts. Our results showed a succession of different nitrifiers from river to sea with bacterial amoA transcripts dominating in the freshwater station while archaeal transcripts were predominant in the marine station. The 16S rRNA sequence analysis revealed that Thaumarchaeota marine group I (MGI) were the most abundant overall but other archaeal groups like Methanosaeta were also potentially active in winter (December-March) and Euryarchaeota marine group II (MGII) were dominant in seawater in summer (April-August). Each station also contained different Thaumarchaeota MGI phylogenetic clusters, and the clusters' microdiversity was associated to specific environmental conditions suggesting the presence of ecotypes adapted to distinct ecological niches. The amoA and ureC transcript dynamics further indicated that some of the Thaumarchaeota MGI subclusters were involved in ammonia oxidation through the hydrolysis of urea. Our findings show that ammonia-oxidizing Archaea and Bacteria were adapted to contrasted conditions and that the Thaumarchaeota MGI diversity probably corresponds to distinct metabolisms or life strategies. PMID:25851445

  14. Rapid Nitrogen Cycling Following Wet-Up Results from Heterotroph, then Nitrifier Response

    Science.gov (United States)

    Placella, S.; Herman, D.; Firestone, M.

    2009-12-01

    The first rainfall following the hot, dry summer in arid and semi-arid ecosystems, known as wet-up, results in large pulses of carbon dioxide and nitrous oxide, two radiatively important gases. Nitrous oxide in general, is produced by nitrifiers and denitrifiers. Using laboratory simulations of wet-up, we monitored soil pools of ammonium and nitrate, gross rates of nitrogen mineralization and nitrification, effluxes of carbon dioxide and nitrous oxide, and gene expression of archaeal and bacterial amoA, a functional gene for nitrification and nirK, a functional gene for denitrification. Results from a California annual grassland soil show significant increases in the ammonium pool within one hour of water addition followed by a significant increase in the nitrate pool within three hours of water addition. Gross nitrogen mineralization and gross nitrification were very high with nitrogen mineralization being highest within three hours of wet-up. Ammonia-oxidizers were most active at nine hours after water addition. Nitrous oxide emissions followed the same pattern as nitrifiers, suggesting nitrification may play an important role in nitrous oxide emissions during wet-up.

  15. Online estimation of wastewater nitrifiable nitrogen, nitrification and denitrification rates, using ORP and DO dynamics.

    Science.gov (United States)

    Spérandio, M; Queinnec, I

    2004-01-01

    Biological nitrogen removal is susceptible to disturbances in activated sludge processes. Significant improvement of performances are obtained by controlling the process taking into account wastewater modifications and sludge activity. In this work a specific sensor is developed, based on oxidation-reduction potential (ORP) and dissolved oxygen (DO) measurements performed in a completely mixed reactor which can be the activated sludge basin itself. This reactor is continuously fed by wastewater and sludge issued from the recirculation stream of the process, and submitted to alternating aeration. DO profiles and ORP bending point are linked to nitrification and denitrification in the sensor. Signal dynamics are treated with a physical model for simultaneously estimating nitrifiable nitrogen concentration in wastewater, nitrification rate, and denitrification rate. Results show very good prediction of experimental oxygen profiles and the software sensor allows us to recalculate nitrate and ammonia profiles in the reactor with a good accuracy. The estimation of nitrifiable nitrogen and removal rates has been validated experimentally. The system allows us to follow highly variable influent nitrogen concentration, toxic events, and changes in the COD concentration or quality in wastewater. PMID:14979535

  16. Monitoring of population shifts in an enriched nitrifying system under gradually increased cadmium loading

    Energy Technology Data Exchange (ETDEWEB)

    Mertoglu, Bulent [Department of Bioengineering, Marmara University, 34722 Goztepe, Istanbul (Turkey)], E-mail: bmertoglu@eng.marmara.edu.tr; Semerci, Neslihan [Department of Environmental Engineering, Marmara University, 34722 Goztepe, Istanbul (Turkey); Guler, Nuray [TUBITAK-Marmara Research Center, Chemistry and Environmental Institute, 41470 Gebze, Kocaeli (Turkey); Calli, Baris [Department of Environmental Engineering, Marmara University, 34722 Goztepe, Istanbul (Turkey); Cecen, Ferhan [Institute of Environmental Sciences, Bogazici University, Bebek, Istanbul (Turkey); Saatci, Ahmet Mete [Department of Environmental Engineering, Marmara University, 34722 Goztepe, Istanbul (Turkey)

    2008-12-30

    The changes in nitrifying bacterial population under cadmium loading were monitored and evaluated in a laboratory scale continuous-flow enriched nitrification system. For this purpose, the following molecular microbiological methods were used: slot-blot hybridization, denaturing gradient gel electrophoresis (DGGE), real-time PCR followed by melting curve analysis, cloning and sequence analysis. The initial cadmium concentration was incrementally increased from 1 to 10 mg/l which led to a drop in ammonia removal efficiency from 99 to 10%. Inhibition was recovered when cadmium loading was stopped. During the second application of cadmium, nitrifying population became more tolerant. Even at 15 mg/l Cd, only a minor inhibition was observed. To investigate the variations in ammonia and nitrite oxidizing bacteria populations in a period of 483 days, ammonia monooxygenase (amoA) and 16S rRNA genes-based molecular techniques were used. An obvious shift was experienced in the diversity of ammonia oxidizers after the first application of 10 mg/l Cd. Metal-tolerant ammonia oxidizing species became dominant and the microbial diversity sharply shifted from Nitrosomonas and Nitrosococcus sp. to Nitrosospira sp. which were observed to tolerate higher cadmium loadings. This result indicated that the extent of nitrification inhibition was not only related to the metal concentration and quantity of microorganisms but also depended on the type of species.

  17. Monochloramine Cometabolism by Mixed-Culture Nitrifiers under Drinking Water Conditions.

    Science.gov (United States)

    Maestre, Juan P; Wahman, David G; Speitel, Gerald E

    2016-06-21

    Chloramines are the second most used secondary disinfectant by United States water utilities. However, chloramination may promote nitrifying bacteria. Recently, monochloramine cometabolism by the pure culture ammonia-oxidizing bacteria, Nitrosomonas europaea, was shown to increase monochloramine demand. The current research investigated monochloramine cometabolism by nitrifying mixed cultures grown under more relevant drinking water conditions and harvested from sand-packed reactors before conducting suspended growth batch kinetic experiments. Four types of batch kinetic experiments were conducted: (1) positive controls to estimate ammonia kinetic parameters, (2) negative controls to account for biomass reactivity, (3) utilization associated product (UAP) controls to account for UAP reactivity, and (4) cometabolism experiments to estimate cometabolism kinetic parameters. Kinetic parameters were estimated in AQUASIM with a simultaneous fit to the experimental data. Cometabolism kinetics were best described by a first-order model. Monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism accounted for 30% of the observed monochloramine loss. These results demonstrated that monochloramine cometabolism occurred in mixed cultures similar to those found in drinking water distribution systems; therefore, monochloramine cometabolism may be a significant contribution to monochloramine loss during nitrification episodes in drinking water distribution systems. PMID:27196729

  18. Influence of temperature on phenanthrene toxicity towards nitrifying bacteria in three soils with different properties.

    Science.gov (United States)

    Suszek-Łopatka, Beata; Maliszewska-Kordybach, Barbara; Klimkowicz-Pawlas, Agnieszka; Smreczak, Bożena

    2016-09-01

    This study focused on the combined effect of environmental conditions (temperature) and contamination (polycyclic aromatic hydrocarbons, PAHs) on the activity of soil microorganisms (nitrifying bacteria). Phenanthrene (Phe) at five contamination levels (0, 1, 10, 100 and 1000 mg kg(-1) dry mass of soil) was employed as a model PAH compound in laboratory experiments that were conducted at three temperatures (i.e., 20 °C (recommended by ISO 15685 method), 15 and 30 °C). Three soils with different properties were used in these studies, and the activity of the nitrifying bacteria was assessed based on nitrification potential (NP) determinations. For the statistical evaluation of the results, the ANCOVA (analysis of covariance) method for three independent variables (i.e., temperature, phenanthrene concentration, soil matrix (as a qualitative variable)) and their interactions was employed. The results indicated on the significant interaction of all studied factors. Temperature influenced the toxicity of Phe towards NP, and this effect was related to the Phe concentration as well as was varied for the different soils. A low content of soil organic matter (controlling bioavailability of phenanthrene to soil microorganisms) enhanced the combined effect of temperature and Phe toxicity, and a high biological activity of the soil (high NP values) increased the effect of high temperature on the Phe stimulatory influence. The results indicate that the temperature should not be neglected in tests evaluating PAH ecotoxicity, especially for reliable ecological risk assessment. PMID:27394082

  19. Production of NO2/-/ and N2O by nitrifying bacteria at reduced concentrations of oxygen

    Science.gov (United States)

    Goreau, T. J.; Kaplan, W. A.; Wofsy, S. C.; Mcelroy, M. B.; Valois, F. W.; Watson, S. W.

    1980-01-01

    The influence of oxygen concentration on the production of NO2(-) and N2O by nitrifying marine bacteria of the genus Nitrosomonas is investigated. Pure cultures of the ammonium-oxiding bacteria isolated from the Western Tropical Atlantic Ocean were grown at oxygen partial pressures from 0.005 to 0.2 atm, and concentrations of N2O in the air above the growth medium and dissolved NO2(-) were determined. Decreasing oxygen concentrations are observed to induce a marked decrease in NO2(-) production rates and increase in N2O evolution, leading to an increase of the relative yield of N2O with respect to NO2(-) from 0.3% to nearly 10%. Similar yields of N2O at atmospheric oxygen levels are found for nitrifying bacteria of the genera Nitrosomonas, Nitrosolobus, Nitrosospira and Nitrosococcus, while nitrite-oxydizing bacteria and a dinoflagellate did not produce detectable quantities of N2O. Results support the view that nitrification is a major source of N2O in the environment.

  20. Bioreactor and methods for producing synchronous cells

    Science.gov (United States)

    Helmstetter, Charles E. (Inventor); Thornton, Maureen (Inventor); Gonda, Steve (Inventor)

    2005-01-01

    Apparatus and methods are directed to a perfusion culture system in which a rotating bioreactor is used to grow cells in a liquid culture medium, while these cells are attached to an adhesive-treated porous surface. As a result of this arrangement and its rotation, the attached cells divide, with one cell remaining attached to the substrate, while the other cell, a newborn cell is released. These newborn cells are of approximately the same age, that are collected upon leaving the bioreactor. The populations of newborn cells collected are of synchronous and are minimally, if at all, disturbed metabolically.

  1. Modelling the biological performance of a side-stream membrane bioreactor using ASM1

    Institute of Scientific and Technical Information of China (English)

    TIAN Ke-jun; LIU Xin-ai; JIANG Tao; M.D. Kennedy; J.C. Schippers; P.A. Vanrolleghem

    2004-01-01

    Membrane bioreactors(MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modelling of a side-stream MBR system using Activated Sludge Model No.1(ASM1), and comparing the results with the modelling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated(i.e. YH=0.72gCOD/gCOD, YA=0.25gCOD/gN, bH=0.25 d-1, bA=0.080 d-1 and fP=0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. A sensitivity analysis for steady state operation and DO dynamics suggested that the biological performance of the MBR system(the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters(i.e. YH, YA, bH, bA, (maxH and (maxA), and influent wastewater components(XI, Ss, Xs, SNH).

  2. Preservation of Nitrifying Capacity and Nitrate Availability in Waterlogged Soils by Radial Oxygen Loss from Roots of Wetland Plants

    NARCIS (Netherlands)

    Engelaar, W.M.H.G.; Symens, J.C.; Laanbroek, H.J.; Blom, C.W.P.M.

    1995-01-01

    The effects of radial O-2 loss from roots on nitrification and NO3- availability were studied. Plants of the flooding- resistant species Rumex palustris and the flooding-sensitive species Rumex thyrsiflorus were grown on drained and waterlogged soils with an initially high nitrifying capacity. Nitra

  3. Nitrifying moving bed biofilm reactor (MBBR) biofilm and biomass response to long term exposure to 1 °C.

    Science.gov (United States)

    Hoang, V; Delatolla, R; Abujamel, T; Mottawea, W; Gadbois, A; Laflamme, E; Stintzi, A

    2014-02-01

    This study aims to investigate moving bed biofilm reactor (MBBR) nitrification rates, nitrifying biofilm morphology, biomass viability as well as bacterial community shifts during long-term exposure to 1 °C. Long-term exposure to 1 °C is the key operational condition for potential ammonia removal upgrade units to numerous northern region treatment systems. The average laboratory MBBR ammonia removal rate after long-term exposure to 1 °C was measured to be 18 ± 5.1% as compared to the average removal rate at 20 °C. Biofilm morphology and specifically the thickness along with biomass viability at various depths in the biofilm were investigated using variable pressure electron scanning microscope (VPSEM) imaging and confocal laser scanning microscope (CLSM) imaging in combination with viability live/dead staining. The biofilm thickness along with the number of viable cells showed significant increases after long-term exposure to 1 °C. Hence, this study observed nitrifying bacteria with higher activities at warm temperatures and a slightly greater quantity of nitrifying bacteria with lower activities at cold temperatures in nitrifying MBBR biofilms. Using DNA sequencing analysis, Nitrosomonas and Nitrosospira (ammonia oxidizers) as well as Nitrospira (nitrite oxidizer) were identified and no population shift was observed between 20 °C and after long-term exposure to 1 °C.

  4. Preservation of Nitrifying Capacity and Nitrate Availability in Waterlogged Soils by Radial Oxygen Loss from Roots of Wetland Plants

    NARCIS (Netherlands)

    Engelaar, W.M.H.G; Symens, J.C.; Laanbroek, H.J.; Blom, C.W.P.M.

    1995-01-01

    The effects of radial 02 loss from roots on nitrification and NO3- availability were studied. Plants of the flooding-resistant species Rumex palustris and the flooding-sensitive species Rumex thyrsiflorus were grown on drained and waterlogged soils with an initially high nitrifying capacity. Nitrate

  5. 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;

    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...

  6. 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;

    2013-01-01

    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...

  7. Sulfate-reducing bacteria in anaerobic bioreactors.

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.

    1998-01-01

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

  8. Computational fluid dynamics simulation of bioreactors

    Directory of Open Access Journals (Sweden)

    Bjørn H. Hjertager

    1995-10-01

    Full Text Available Multi-dimensional models of flow processes in bioreactors are presented. Particular emphasis is given to models that use the two-fluid technique. The models use a two-equation turbuluence model and a Monod type kinetic reaction model. Predictions are given for both bubble column and mechanically stirred reactors.

  9. Vortex breakdown in a truncated conical bioreactor

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.;

    2015-01-01

    This numerical study explains the eddy formation and disappearance in a slow steady axisymmetric air–water flow in a vertical truncated conical container, driven by the rotating top disk. Numerous topological metamorphoses occur as the water height, Hw, and the bottom-sidewall angle, α, vary. It ...... are of fundamental interest and can be relevant for aerial bioreactors....

  10. Denitrifying bioreactor clogging potential during wastewater treatment

    Science.gov (United States)

    Chemoheterotrophic denitrification technologies using woodchips as a solid carbon source (i.e., woodchip bioreactors) have been widely trialed for treatment of diffuse-source agricultural nitrogen pollution. There is growing interest in the use of this simple, relatively low-cost biological wastewat...

  11. LANDFILL BIOREACTOR PERFORMANCE, SECOND INTERIM REPORT

    Science.gov (United States)

    A bioreactor landfill is a landfill that is operated in a manner that is expected to increase the rate and extent of waste decomposition, gas generation, and settlement compared to a traditional landfill. This Second Interim Report was prepared to provide an interpretation of fie...

  12. Critical Review of Membrane Bioreactor Models

    DEFF Research Database (Denmark)

    Naessens, W.; Maere, T.; Ratkovich, Nicolas Rios;

    2012-01-01

    Membrane bioreactor technology exists for a couple of decades, but has not yet overwhelmed the market due to some serious drawbacks of which operational cost due to fouling is the major contributor. Knowledge buildup and optimisation for such complex systems can heavily benefit from mathematical...

  13. MONITORING APPROACHES FOR BIOREACTOR LANDFILLS - Report

    Science.gov (United States)

    Experimental bioreactor landfill operations at operating Municipal Solid Waste (MSW) landfills can be approved under the research development and demonstration (RD&D) provisions of 30CFR 258.4. To provide a basis for consistent data collection for future decision-making in suppor...

  14. Engineering skeletal muscle tissue in bioreactor systems

    Institute of Scientific and Technical Information of China (English)

    An Yang; Li Dong

    2014-01-01

    Objective To give a concise review of the current state of the art in tissue engineering (TE) related to skeletal muscle and kinds of bioreactor environment.Data sources The review was based on data obtained from the published articles and guidelines.Study selection A total of 106 articles were selected from several hundred original articles or reviews.The content of selected articles is in accordance with our purpose and the authors are authorized scientists in the study of engineered muscle tissue in bioreactor.Results Skeletal muscle TE is a promising interdisciplinary field which aims at the reconstruction of skeletal muscle loss.Although numerous studies have indicated that engineering skeletal muscle tissue may be of great importance in medicine in the near future,this technique still represents a limited degree of success.Since tissue-engineered muscle constructs require an adequate connection to the vascular system for efficient transport of oxygen,carbon dioxide,nutrients and waste products.Moreover,functional and clinically applicable muscle constructs depend on adequate neuromuscular junctions with neural calls.Third,in order to engineer muscle tissue successfully,it may be beneficial to mimic the in vivo environment of muscle through association with adequate stimuli from bioreactors.Conclusion Vascular system and bioreactors are necessary for development and maintenance of engineered muscle in order to provide circulation within the construct.

  15. Establishing Liver Bioreactors for In Vitro Research.

    Science.gov (United States)

    Rebelo, Sofia P; Costa, Rita; Sousa, Marcos F Q; Brito, Catarina; Alves, Paula M

    2015-01-01

    In vitro systems that can effectively model liver function for long periods of time are fundamental tools for preclinical research. Nevertheless, the adoption of in vitro research tools at the earliest stages of drug development has been hampered by the lack of culture systems that offer the robustness, scalability, and flexibility necessary to meet industry's demands. Bioreactor-based technologies, such as stirred tank bioreactors, constitute a feasible approach to aggregate hepatic cells and maintain long-term three-dimensional cultures. These three-dimensional cultures sustain the polarity, differentiated phenotype, and metabolic performance of human hepatocytes. Culture in computer-controlled stirred tank bioreactors allows the maintenance of physiological conditions, such as pH, dissolved oxygen, and temperature, with minimal fluctuations. Moreover, by operating in perfusion mode, gradients of soluble factors and metabolic by-products can be established, aiming at resembling the in vivo microenvironment. This chapter provides a protocol for the aggregation and culture of hepatocyte spheroids in stirred tank bioreactors by applying perfusion mode for the long-term culture of human hepatocytes. This in vitro culture system is compatible with feeding high-throughput screening platforms for the assessment of drug elimination pathways, being a useful tool for toxicology research and drug development in the preclinical phase. PMID:26272143

  16. Anaerobic membrane bioreactors: Are membranes really necessary?

    NARCIS (Netherlands)

    Davila, M.; Kassab, G.; Klapwijk, A.; Lier, van J.B.

    2008-01-01

    Membranes themselves represent a significant cost for the full scale application of anaerobic membrane bioreactors (AnMBR). The possibility of operating an AnMBR with a self-forming dynamic membrane generated by the substances present in the reactor liquor would translate into an important saving. A

  17. Establishing Liver Bioreactors for In Vitro Research.

    Science.gov (United States)

    Rebelo, Sofia P; Costa, Rita; Sousa, Marcos F Q; Brito, Catarina; Alves, Paula M

    2015-01-01

    In vitro systems that can effectively model liver function for long periods of time are fundamental tools for preclinical research. Nevertheless, the adoption of in vitro research tools at the earliest stages of drug development has been hampered by the lack of culture systems that offer the robustness, scalability, and flexibility necessary to meet industry's demands. Bioreactor-based technologies, such as stirred tank bioreactors, constitute a feasible approach to aggregate hepatic cells and maintain long-term three-dimensional cultures. These three-dimensional cultures sustain the polarity, differentiated phenotype, and metabolic performance of human hepatocytes. Culture in computer-controlled stirred tank bioreactors allows the maintenance of physiological conditions, such as pH, dissolved oxygen, and temperature, with minimal fluctuations. Moreover, by operating in perfusion mode, gradients of soluble factors and metabolic by-products can be established, aiming at resembling the in vivo microenvironment. This chapter provides a protocol for the aggregation and culture of hepatocyte spheroids in stirred tank bioreactors by applying perfusion mode for the long-term culture of human hepatocytes. This in vitro culture system is compatible with feeding high-throughput screening platforms for the assessment of drug elimination pathways, being a useful tool for toxicology research and drug development in the preclinical phase.

  18. Continuous-Flow Gas-Phase Bioreactors

    Science.gov (United States)

    Wise, Donald L.; Trantolo, Debra J.

    1994-01-01

    Continuous-flow gas-phase bioreactors proposed for biochemical, food-processing, and related industries. Reactor contains one or more selected enzymes dehydrated or otherwise immobilized on solid carrier. Selected reactant gases fed into reactor, wherein chemical reactions catalyzed by enzyme(s) yield product biochemicals. Concept based on discovery that enzymes not necessarily placed in traditional aqueous environments to function as biocatalysts.

  19. Contribution of Methanotrophic and Nitrifying Bacteria to CH4 and NH4+ Oxidation in the Rhizosphere of Rice Plants as Determined by New Methods of Discrimination

    OpenAIRE

    Bodelier, Paul L. E.; Frenzel, Peter

    1999-01-01

    Methanotrophic and nitrifying bacteria are both able to oxidize CH4 as well as NH4+. To date it is not possible to estimate the relative contribution of methanotrophs to nitrification and that of nitrifiers to CH4 oxidation and thus to assess their roles in N and C cycling in soils and sediments. This study presents new options for discrimination between the activities of methanotrophs and nitrifiers, based on the competitive inhibitor CH3F and on recovery after inhibition with C2H2. By using...

  20. Coupling autotrophic sulfide mineral weathering with dolomite dissolution in a subglacial ecosystem

    Science.gov (United States)

    Boyd, E. S.; Hamilton, T. L.; Havig, J. R.; Lange, R.; Murter, E.; Skidmore, M. L.; Peters, J.; Shock, E.

    2013-12-01

    Evidence in the rock record suggests that glaciers have been present and covered a significant portion of the Earth's surface since the putative Mozaan Glaciation (circa 2.9 Ga) and were demonstrated recently to host active microbial communities that impact local and global biogeochemical cycles. In the present study, we applied a microcosm-based radioisotopic biocarbonate tracer approach to quantify rates of inorganic carbon assimilation in sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada at 4°C. Rates of inorganic carbon assimilation were stimulated by the addition of ammonium and phosphate, suggesting that these nutrients might be of limited supply in the subglacial environment or, in the case of ammonia, might be serving as a source of reductant fueling inorganic carbon fixation. Geochemical analyses were used to assess the potential redox couples that might be fueling autotrophic activity. The difference in the concentration of sulfate (2.4 mM) in unamended microcosm fluids when compared to fluids sampled from killed controls following 180 days incubation suggests that inorganic carbon assimilation in microcosms is driven by microbial populations involved in the oxidation of mineral sulfides, most likely pyrite. Amendment of microcosms with 1 mM ammonia led to near stoichiometric production of nitrate (~890 μM) and lower production of sulfate (~1.5 mM), indicating that the enhanced activity observed in ammonia treated microcosms is likely due to the stimulation of autotrophic ammonia oxidizing populations. The isotopic composition of dissolved organic carbon in subglacial meltwaters ranged was -24.40 ‰ versus VPDB, which is consistent with a source for this organic carbon via the activity of autotrophs that use the Calvin cycle of inorganic carbon fixation. Quantification and sequencing of transcripts of Calvin cycle biomarker genes (ribulose-1,5 bisphosphate carboxylase/oxygenase, encoded by cbbL) suggest the presence of a ubiquitous

  1. 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.

  2. 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.

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

    Science.gov (United States)

    Zaybak, Zehra; Pisciotta, John M; Tokash, Justin C; Logan, Bruce E

    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 ± 4 mA/m(2). 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.

  4. Bioreactors in tissue engineering - principles, applications and commercial constraints.

    Science.gov (United States)

    Hansmann, Jan; Groeber, Florian; Kahlig, Alexander; Kleinhans, Claudia; Walles, Heike

    2013-03-01

    Bioreactor technology is vital for tissue engineering. Usually, bioreactors are used to provide a tissue-specific physiological in vitro environment during tissue maturation. In addition to this most obvious application, bioreactors have the potential to improve the efficiency of the overall tissue-engineering concept. To date, a variety of bioreactor systems for tissue-specific applications have been developed. Of these, some systems are already commercially available. With bioreactor technology, various functional tissues of different types were generated and cultured in vitro. Nevertheless, these efforts and achievements alone have not yet led to many clinically successful tissue-engineered implants. We review possible applications for bioreactor systems within a tissue-engineering process and present basic principles and requirements for bioreactor development. Moreover, the use of bioreactor systems for the expansion of clinically relevant cell types is addressed. In contrast to cell expansion, for the generation of functional three-dimensional tissue equivalents, additional physical cues must be provided. Therefore, bioreactors for musculoskeletal tissue engineering are discussed. Finally, bioreactor technology is reviewed in the context of commercial constraints.

  5. 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

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

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Mutlu, Ayten Gizem;

    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...

  7. Control of SHARON reactor for autotrophic nitrogen removal in two-reactor configuration

    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 explores the control design for a SHARON reactor. With this aim, a full model is developed, including the pH dependency, in order to simulate the reactor and determine the optimal operating...... conditions. Then, the screening of controlled variables and pairing is carried out by an assessment of the effect of the disturbances based on the closed loop disturbance gain plots. Two controlled structures are obtained and benchmarked by their capacity to reject the disturbances before the Anammox reactor....

  8. Incremental design of control system of SHARON-Anammox process for autotrophic nitrogen removal

    DEFF Research Database (Denmark)

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

    2012-01-01

    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work explores the control design for a SHARON-Anammox reactor sequence. With this aim, a full model is developed, including the pH dependency, in order to simulate the reactor and determine...... the optimal operating conditions. Then, the screening of controlled variables and pairing is carried out by an assessment of the effect of the disturbances based on the closed loop disturbance gain plots. Three control structures are obtained and benchmarked by their capacity to reject the disturbances before...... the Anammox reactor....

  9. Acclimation Behavior of Nitrifying Sludge Against Trichloroethylene by Membrane Bioreactor%膜生物反应器中污泥的TCE硝化反应特性

    Institute of Scientific and Technical Information of China (English)

    丁原红; 熊小京; 洪华生

    2003-01-01

    采用一体式浸没膜生物反应器,在曝气、连续的条件下,间歇投加硝化反应的抑制物TCE(三氯乙烯),考察在不同TCE投加浓度下,TCE及其共代谢中间产物对硝化菌和异养菌活性的抑制情况,以及在TCE停止投加后,污泥相对硝化活性的变化趋势.虽然TCE对异养菌酶活性有一定的抑制作用,使CODMn的去除率呈下降趋势,但仍然没有被大幅度地降低;硝化菌由于对环境比较敏感,在TCE投加的初期,受抑制作用比较明显,氨氮的去除率呈下降趋势,但当硝化菌慢慢适应TCE共存环境后,其硝化活性将慢慢恢复,氨氮去除率将逐渐提高;停止投加TCE后,硝化菌仍然具有一定的耐TCE抑制的能力,且较高浓度TCE驯化的污泥的耐TCE抑制的能力也较高,但随着停止投加时间的延长,这种耐TCE抑制的能力将逐渐下降,直至消失.

  10. Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

    Institute of Scientific and Technical Information of China (English)

    TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue

    2009-01-01

    Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

  11. Attempts to improve nitrogen utilization efficiency of aquaponics through nitrifies addition and filler gradation.

    Science.gov (United States)

    Zou, Yina; Hu, Zhen; Zhang, Jian; Xie, Huijun; Liang, Shuang; Wang, Jinhe; Yan, Runxin

    2016-04-01

    Aquaponics has attracted worldwide attention in recent years and is considered as an alternative technology for conventional aquaculture. In this study, common carp (Cyprinus carpio) and pakchoi (Brassica chinensis) were cultured in lab-scale aquaponics, and attempts were conducted to enhance its nitrogen utilization efficiency (NUE) through two optimization methods, i.e., nitrifies addition (NA) and filler gradation (FG). Results showed that NA and FG could improve the NUE of aquaponics by 8.8 and 16.0%, respectively, compared with control. The total ammonia (TAN) and nitrite (NO2(-)) concentrations in NA and FG systems were maintained at relatively low level (TAN aquaponics also contributed to global warming. Although the two proposed attempts in this study caused more N2O emission, they made new breakthrough in improving the NUE of aquaponics.

  12. Biofilm Thickness Influences Biodiversity in Nitrifying MBBRs-Implications on Micropollutant Removal

    DEFF Research Database (Denmark)

    Torresi, Elena; Fowler, Jane; Polesel, Fabio;

    2016-01-01

    In biofilm systems for wastewater treatment (e.g., moving bed biofilms reactors-MBBRs) biofilm thickness is typically not under direct control. Nevertheless, biofilm thickness is likely to have a profound effect on the microbial diversity and activity, as a result of diffusion limitation and thus...... substrate penetration in the biofilm. In this study, we investigated the impact of biofilm thickness on nitrification and on the removal of more than 20 organic micropollutants in laboratory-scale nitrifying MBBRs. We used novel carriers (Z-carriers, AnoxKaldnes) that allowed controlling biofilm thickness...... at 50, 200, 300, 400, and 500 μm. The impact of biofilm thickness on microbial community was assessed via 16S rRNA gene amplicon sequencing and ammonia monooxygenase (amoA) abundance quantification through quantitative PCR (qPCR). Results from batch experiments and microbial analysis showed that (i...

  13. Attempts to improve nitrogen utilization efficiency of aquaponics through nitrifies addition and filler gradation.

    Science.gov (United States)

    Zou, Yina; Hu, Zhen; Zhang, Jian; Xie, Huijun; Liang, Shuang; Wang, Jinhe; Yan, Runxin

    2016-04-01

    Aquaponics has attracted worldwide attention in recent years and is considered as an alternative technology for conventional aquaculture. In this study, common carp (Cyprinus carpio) and pakchoi (Brassica chinensis) were cultured in lab-scale aquaponics, and attempts were conducted to enhance its nitrogen utilization efficiency (NUE) through two optimization methods, i.e., nitrifies addition (NA) and filler gradation (FG). Results showed that NA and FG could improve the NUE of aquaponics by 8.8 and 16.0%, respectively, compared with control. The total ammonia (TAN) and nitrite (NO2(-)) concentrations in NA and FG systems were maintained at relatively low level (TAN aquaponics also contributed to global warming. Although the two proposed attempts in this study caused more N2O emission, they made new breakthrough in improving the NUE of aquaponics. PMID:26645232

  14. Stimulatory effect of xenobiotics on oxidative electron transport of chemolithotrophic nitrifying bacteria used as biosensing element.

    Directory of Open Access Journals (Sweden)

    Andrzej Woznica

    Full Text Available Electron transport chain (ETCh of ammonium (AOB and nitrite oxidizing bacteria (NOB participates in oxidation of ammonium to nitrate (nitrification. Operation of ETCh may be perturbed by a range of water-soluble xenobiotics. Therefore, consortia of nitrifying bacteria may be used as a biosensor to detect water contamination. A surprising feature of this system is an increase of oxygen consumption, detected in the presence of certain inhibitors of ETCh. Thus, to shed light on the mechanism of this effect (and other differences between inhibitors we monitored separately respiration of the bacteria of the first (AOB - Nitrosomonas and second (NOB -Nitrobacter stages of nitrification. Furthermore, we measured plasma membrane potential and the level of reduction of NAD(PH. We propose a novel model of ETCh in NOB to explain the role of reverse electron transport in the stimulation of oxygen consumption (previously attributed to hormesis.

  15. Preliminary Study on the Heterotrophic Bacteria and Autotrophic Bacteria in the Water Body of the Juoenile Trionyx%稚鳖养殖水体中异养细菌及自养细菌的初步研究

    Institute of Scientific and Technical Information of China (English)

    运珞珈; 李谷; 刘志伟; 唐非; 刘红艳

    2000-01-01

    Heterotrophic bacteria and autotrophic bacteria were identified and counted in the water body and the sediment of the juvenile triongx. The results showed that total number of heterortrophic bacteria in the water body and sediment were (5. 3-17. 0) × 105 CFU/ml and (1. 0-1. 5) × 106 CFU/g (wet weight) respectively. Total number of 3 genus of autotrophic bacteria were 8. 5 MPN/ml, 0. 4 MPN/ml and 2. 45 MPN/ml, respectively. The number of autoterophic bacteria were significantly lower than the heterotrophic bacteria. Majority of 21 strains of heterotrophic bacteria that isolated from water body were Pseudomonas. Majority of 25 strains of heterotrophic bacteria isolated from sediment were bacillus, microccus and Pseudomonas.Three genus of autotrophic bacteria were sulphuret bacteria, nitrify bacteria and nitrosobacteria that were capable of oxidizing H2S, S, FeS, oxidizing NH3 to NO2 and NO2 to NO3 respectively. The chemical indicators (BOD5, NH3-N and S) in the water body were determined and they overrun the fishery, water quality standard. Sulphuret approached the maximum limit in the fishponct water body. The 3 breed water body was heavily polluted.%对D湖水产养殖场,室内养鳖池水体和底泥中的异养细菌及自养细菌种类、数量进行了初步测定分析。结果表明水中异养细菌总数为5.3×105~1 7.0×105 CFU/ml,底泥中异养细菌总数为1.66×106~2.24×106CFU/ml(湿重)。三种自养细菌的总数(用最大可能数MPN法测得)分别为8.5MPN/ml,0.4MPN/m1,2.45MPN/ml。自养细菌的数量明显低于异养细菌。试验稚鳖池水中共分离出21株异养细菌,其中优势菌为假单胞杆菌属细菌(Pseudomonas);底泥中共分离出25株异养细菌,其中优势菌为芽胞杆菌属细菌(Bacillus),微球菌属细菌(Micrococcus)假单胞菌属细菌(Pseudomonas),三种自养细菌分别为具有氧化硫化氢、元素硫或硫化亚铁的硫细菌;具有氧化氨

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Perchlorate reduction by hydrogen autotrophic bacteria and microbial community analysis using high-throughput sequencing.

    Science.gov (United States)

    Wan, Dongjin; Liu, Yongde; Niu, Zhenhua; Xiao, Shuhu; Li, Daorong

    2016-02-01

    Hydrogen autotrophic reduction of perchlorate have advantages of high removal efficiency and harmless to drinking water. But so far the reported information about the microbial community structure was comparatively limited, changes in the biodiversity and the dominant bacteria during acclimation process required detailed study. In this study, perchlorate-reducing hydrogen autotrophic bacteria were acclimated by hydrogen aeration from activated sludge. For the first time, high-throughput sequencing was applied to analyze changes in biodiversity and the dominant bacteria during acclimation process. The Michaelis-Menten model described the perchlorate reduction kinetics well. Model parameters q(max) and K(s) were 2.521-3.245 (mg ClO4(-)/gVSS h) and 5.44-8.23 (mg/l), respectively. Microbial perchlorate reduction occurred across at pH range 5.0-11.0; removal was highest at pH 9.0. The enriched mixed bacteria could use perchlorate, nitrate and sulfate as electron accepter, and the sequence of preference was: NO3(-) > ClO4(-) > SO4(2-). Compared to the feed culture, biodiversity decreased greatly during acclimation process, the microbial community structure gradually stabilized after 9 acclimation cycles. The Thauera genus related to Rhodocyclales was the dominated perchlorate reducing bacteria (PRB) in the mixed culture.

  7. Absorption and utilization of organic matter by the strict autotroph, Thiobacillus thiooxidans, with special reference to aspartic acid.

    Science.gov (United States)

    Butler, R G; Umbreit, W W

    1966-02-01

    Butler, Richard G. (Rutgers, The State University, New Brunswick, N.J.), and Wayne W. Umbreit. Absorption and utilization of organic matter by the strict autotroph, Thiobacillus thiooxidans, with special reference to aspartic acid. J. Bacteriol. 91:661-666. 1966.-The strictly autotrophic bacterium, Thiobacillus thiooxidans, can be shown to assimilate a variety of organic materials. Aspartic acid can be assimilated into protein and can be converted into CO(2), but even in the presence of sulfur it cannot serve as the sole source of carbon for growth. The reason appears to be that aspartic acid is converted into inhibitory materials.

  8. Bioreactor and process design for biohydrogen production.

    Science.gov (United States)

    Show, Kuan-Yeow; Lee, Duu-Jong; Chang, Jo-Shu

    2011-09-01

    Biohydrogen is regarded as an attractive future clean energy carrier due to its high energy content and environmental-friendly conversion. It has the potential for renewable biofuel to replace current hydrogen production which rely heavily on fossil fuels. While biohydrogen production is still in the early stage of development, there have been a variety of laboratory- and pilot-scale systems developed with promising potential. This work presents a review of advances in bioreactor and bioprocess design for biohydrogen production. The state-of-the art of biohydrogen production is discussed emphasizing on production pathways, factors affecting biohydrogen production, as well as bioreactor configuration and operation. Challenges and prospects of biohydrogen production are also outlined.

  9. Filterability and Sludge Concentration in Membrane Bioreactors

    OpenAIRE

    Lousada-Ferreira, M

    2011-01-01

    The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of the sludge to be filtrated through a membrane, in a wastewater treatment system designated as Membrane Bioreactor (MBR). An MBR is a wastewater treatment system that combines an activated sludge proc...

  10. Anaerobic membrane bioreactors: Are membranes really necessary?

    OpenAIRE

    Davila, M.; Kassab, G.; Klapwijk, A.; Van, Lier, G

    2008-01-01

    Membranes themselves represent a significant cost for the full scale application of anaerobic membrane bioreactors (AnMBR). The possibility of operating an AnMBR with a self-forming dynamic membrane generated by the substances present in the reactor liquor would translate into an important saving. A self-forming dynamic membrane only requires a support material over which a cake layer is formed, which determines the rejection properties of the system. The present research studies the applicat...

  11. Engineering stem cell niches in bioreactors

    OpenAIRE

    2013-01-01

    Stem cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells and amniotic fluid stem cells have the potential to be expanded and differentiated into various cell types in the body. Efficient differentiation of stem cells with the desired tissue-specific function is critical for stem cell-based cell therapy, tissue engineering, drug discovery and disease modeling. Bioreactors provide a great platform to regulate the stem cell microenvironment, known as “ni...

  12. Oxygen transfer in a pressurized airlift bioreactor.

    Science.gov (United States)

    Campani, Gilson; Ribeiro, Marcelo Perencin Arruda; Horta, Antônio Carlos Luperni; Giordano, Roberto Campos; Badino, Alberto Colli; Zangirolami, Teresa Cristina

    2015-08-01

    Airlift bioreactors (ALBs) offer advantages over conventional systems, such as simplicity of construction, reduced risk of contamination, and efficient gas-liquid dispersion with low power consumption. ALBs are usually operated under atmospheric pressure. However, in bioprocesses with high oxygen demand, such as high cell density cultures, oxygen limitation may occur even when operating with high superficial gas velocity and air enriched with oxygen. One way of overcoming this drawback is to pressurize the reactor. In this configuration, it is important to assess the influence of bioreactor internal pressure on the gas hold-up, volumetric oxygen transfer coefficient (k(L)a), and volumetric oxygen transfer rate (OTR). Experiments were carried out in a concentric-tube airlift bioreactor with a 5 dm(3) working volume, equipped with a system for automatic monitoring and control of the pressure, temperature, and inlet gas flow rate. The results showed that, in disagreement with previous published results for bubble column and external loop airlift reactors, overpressure did not significantly affect k(L)a within the studied ranges of pressure (0.1-0.4 MPa) and superficial gas velocity in the riser (0.032-0.065 m s(-1)). Nevertheless, a positive effect on OTR was observed: it increased up to 5.4 times, surpassing by 2.3 times the oxygen transfer in a 4 dm(3) stirred tank reactor operated under standard cultivation conditions. These results contribute to the development of non-conventional reactors, especially pneumatic bioreactors operated using novel strategies for oxygen control.

  13. Bioreactor Yields Extracts for Skin Cream

    Science.gov (United States)

    2015-01-01

    Johnson Space Flight Center researchers created a unique rotating-wall bioreactor that simulates microgravity conditions, spurring innovations in drug development and medical research. Renuèll Int'l Inc., based in Aventure, Florida, licensed the technology and used it to produce a healing skin care product, RE`JUVEL. In a Food and Drug Administration test, RE`JUVEL substantially increased skin moisture and elasticity while reducing dark blotches and wrinkles.

  14. Degradation of Refuse in Hybrid Bioreactor Landfill

    Institute of Scientific and Technical Information of China (English)

    YAN LONG; Yu-YANG LONG; HAI-CHUN LIU; DONG-SHENG SHEN

    2009-01-01

    Objectivess To explore the process of refuse decomposition in hybrid bioreactor landfill. Methods The bioreactor landfill was operated in sequencing of facultative-anaerobic and aerobic conditions with leachate recireulation, pH, COD, and ammonia in the leachate and pH, biodegradable organic matter (BDM), and cation exchange capacity (CEC) in refuse were detected. Results CEC increased gradually with the degradation of refuse, which was negatively correlad, With BDM. COD and ammonia in the leachate was declined to 399.2 mg L-1 and 20.6 mg N L-1, respectively, during the 357-day operation. The respective concentrations of ammonia and COD were below the second and the third levels of current discharge standards in China. Conclusion The refuse is relatively stable at the end of hybrid bioreactor landfill operation. Most of the readily biodegradable organic matter is mineralized in the initial phase of refuse degradation, whereas the hard-biodegradable organic matter is mainly humidified in the maturity phase of refuse degradation.

  15. Replaceable Sensor System for Bioreactor Monitoring

    Science.gov (United States)

    Mayo, Mike; Savoy, Steve; Bruno, John

    2006-01-01

    A sensor system was proposed that would monitor spaceflight bioreactor parameters. Not only will this technology be invaluable in the space program for which it was developed, it will find applications in medical science and industrial laboratories as well. Using frequency-domain-based fluorescence lifetime technology, the sensor system will be able to detect changes in fluorescence lifetime quenching that results from displacement of fluorophorelabeled receptors bound to target ligands. This device will be used to monitor and regulate bioreactor parameters including glucose, pH, oxygen pressure (pO2), and carbon dioxide pressure (pCO2). Moreover, these biosensor fluorophore receptor-quenching complexes can be designed to further detect and monitor for potential biohazards, bioproducts, or bioimpurities. Biosensors used to detect biological fluid constituents have already been developed that employ a number of strategies, including invasive microelectrodes (e.g., dark electrodes), optical techniques including fluorescence, and membrane permeable systems based on osmotic pressure. Yet the longevity of any of these sensors does not meet the demands of extended use in spacecraft habitat or bioreactor monitoring. It was therefore necessary to develop a sensor platform that could determine not only fluid variables such as glucose concentration, pO2, pCO2, and pH but can also regulate these fluid variables with controlled feedback loop.

  16. Aujeszky's disease virus production in disposable bioreactor

    Indian Academy of Sciences (India)

    I Slivac; V Gaurina Srček; K Radošević; I Kmetič; Z Kniewald

    2006-09-01

    A novel, disposable-bag bioreactor system that uses wave action for mixing and transferring oxygen was evaluated for BHK 21 C13 cell line growth and Aujeszky’s disease virus (ADV) production. Growth kinetics of BHK 21 C13 cells in the wave bioreactor during 3-day period were determined. At the end of the 3-day culture period and cell density of 1.82 × 106 cells ml–1, the reactor was inoculated with 9 ml of gE- Bartha K-61 strain ADV suspension (105.9 TCID50) with multiplicity of infection (MOI) of 0.01. After a 144 h incubation period, 400 ml of ADV harvest was obtained with titre of 107.0 TCID50 ml–1, which corresponds to 40,000 doses of vaccine against AD. In conclusion, the results obtained with the wave bioreactor using BHK 21 C13 cells showed that this system can be considered as suitable for ADV or BHK 21 C13 cell biomass production.

  17. Linking nitrifying biofilm characteristics and nitrification performance in moving-bed biofilm reactors for polluted raw water pretreatment.

    Science.gov (United States)

    Zhang, Shuangfu; Wang, Yayi; He, Weitao; Xing, Meiyan; Wu, Min; Yang, Jian; Gao, Naiyun; Sheng, Guangyao; Yin, Daqiang; Liu, Shanhu

    2013-10-01

    Biofilm physiology was characterized by four biofilm constituents, i.e., polysaccharides, proteins (PN), humic-like substances and phospholipids (PL), for the first time to explore the relationships between biofilm characteristics and nitrification performance in moving-bed biofilm reactors (MBBRs) designed for pretreatment of polluted raw surface water for potable supply. The biofilm compositions depended highly on the balance of microbial decay and nitrification processes. The increased ammonia loading greatly regulated the community structure, promoting the dominance of nitrifiers and their proportions in the nitrifying biofilm. Nitrification rate and activity correlated linearly with the fractions of volatile solids (VS), PN and PL, which were related to nitrification processes in the biofilm. The specific biofilm activity demonstrated an exponential-asymptotic relationship with ratios of PN/VS and PL/VS. Thus, analyzing biofilm characteristics can be valid for estimating nitrification performance in MBBRs, and may offer engineers with basis to optimize MBBR design and operation.

  18. Distribution and microbial community structure analysis of a single-stage partial nitritation/anammox granular sludge bioreactor operating at low temperature.

    Science.gov (United States)

    Rodriguez-Sanchez, Alejandro; Purswani, Jessica; Lotti, Tommaso; Maza-Marquez, Paula; van Loosdrecht, M C M; Vahala, Riku; Gonzalez-Martinez, Alejandro

    2016-09-01

    In the last decade, autotrophic nitrogen removal technologies based on anammox metabolism have become state of the art in urban and industrial wastewater treatment systems, due to their advantages over traditional nitrogen removal processes. However, their application is currently limited to the treatment of warm wastewater (25-40°C) mainly due to the low growth rate of the anammox bacteria. The extension of the application field to wastewater characterized by lower temperatures (8-20°C), such as those typical for municipal sewage, allows the design of treatment systems with a net energy production. In this study, the distribution and bacterial community structure of a lab-scale single-stage partial nitritation/anammox (PN/A) granular sludge bioreactor operating at low temperatures was analysed using next-generation sequencing techniques. The presence of ammonium-oxidizing bacteria and anammox bacteria was found, but the appearance of other bacterial species shows a complex microbial ecosystem. Evaluation of ecological roles of representative species inside the single-stage PN/A bioreactor was accomplished. Results obtained will be helpful for the future design and operation of PN/A systems performing at low temperatures. PMID:26829222

  19. Effect of land use on the density of nitrifying and denitrifying bacteria in the colombian coffee region

    OpenAIRE

    Vallejo Quintero, Victoria Eugenia; Gómez, María M.; Cubillos, Ana M.; Roldán, Fabio

    2012-01-01

    Soil microbial communities involved in the cycling of nitrogen (N) are essential to maintaining and improving soil fertility, productivity and functionality of natural and agricultural ecosystems. However, some compounds generated during the metabolic processes performed by nitrifying (NB) and denitrifying (DB) bacteria are associated with the production of greenhouse gases, groundwater pollution and acidification. Therefore, the study of these bacteria is essential for economic and environme...

  20. Nitrogen-removal performance and community structure of nitrifying bacteria under different aeration modes in an oxidation ditch.

    Science.gov (United States)

    Guo, Chang-Zi; Fu, Wei; Chen, Xue-Mei; Peng, Dang-Cong; Jin, Peng-Kang

    2013-07-01

    Oxidation-ditch operation modes were simulated using sequencing batch reactors (SBRs) with alternate stirring and aerating. The nitrogen-removal efficiencies and nitrifying characteristics of two aeration modes, point aeration and step aeration, were investigated. Under the same air-supply capacity, oxygen dissolved more efficiently in the system with point aeration, forming a larger aerobic zone. The nitrifying effects were similar in point aeration and step aeration, where the average removal efficiencies of NH4(+) N were 98% and 96%, respectively. When the proportion of anoxic and oxic zones was 1, the average removal efficiencies of total nitrogen (TN) were 45% and 66% under point aeration and step aeration, respectively. Step aeration was more beneficial to both anoxic denitrification and simultaneous nitrification and denitrification (SND). The maximum specific ammonia-uptake rates (AUR) of point aeration and step aeration were 4.7 and 4.9 mg NH4(+)/(gMLVSS h), respectively, while the maximum specific nitrite-uptake rates (NUR) of the two systems were 7.4 and 5.3 mg NO2(-)-N/(gMLVSS h), respectively. The proportions of ammonia-oxidizing bacteria (AOB) to all bacteria were 5.1% under point aeration and 7.0% under step aeration, and the proportions of nitrite-oxidizing bacteria (NOB) reached 6.5% and 9.0% under point and step aeration, respectively. The dominant genera of AOB and NOB were Nitrosococcus and Nitrospira, which accounted for 90% and 91%, respectively, under point aeration, and the diversity of nitrifying bacteria was lower than under step aeration. Point aeration was selective of nitrifying bacteria. The abundance of NOB was greater than that of AOB in both of the operation modes, and complete transformation of NH4(+) N to NO3(-)-N was observed without NO2(-)-N accumulation.

  1. Preservation of nitrifying capacity and nitrate availability in waterlogged soils by radial oxygen loss from roots of wetland plants

    OpenAIRE

    Engelaar, W.M.H.G.; Symens, J.C.; Laanbroek, H. J.; Blom, C.W.P.M.

    1995-01-01

    The effects of radial 02 loss from roots on nitrification and NO3- availability were studied. Plants of the flooding-resistant species Rumex palustris and the flooding-sensitive species Rumex thyrsiflorus were grown on drained and waterlogged soils with an initially high nitrifying capacity. Nitrate reductase activity in the plant leaves was used as an indicator of NO3- availability to the plants. In a separate experiment these species were shown to have higher levels of nitrate reductase act...

  2. Culture-independent detection of 'TM7' bacteria in a streptomycin-resistant acidophilic nitrifying process

    Energy Technology Data Exchange (ETDEWEB)

    Kurogi, T.; Linh, N. T. T.; Kuroki, T.; Yamada, T. [Department of Environmental and Life Science, Toyohashi University of Technology, Toyohashi 441-8580 (Japan); Hiraishi, A. [Department of Environmental and Life Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan and Electronics-inspired Interdisciplinary Institute (EIIRIS), Toyohashi University of Technology, Toyohashi 441-8580 (Japan)

    2014-02-20

    Nitrification in biological wastewater treatment processes has been believed for long time to take place under neutral conditions and is inhibited under acidic conditions. However, we previously constructed acidophilic nitrifying sequencing-batch reactors (ANSBRs) being capable of nitrification at < pH 4 and harboring bacteria of the candidate phylum 'TM7' as the major constituents of the microbial community. In light of the fact that the 16S rRNA of TM7 bacteria has a highly atypical base substitution possibly responsible for resistance to streptomycin at the ribosome level, this study was undertaken to construct streptomycin-resistant acidophilic nitrifying (SRAN) reactors and to demonstrate whether TM7 bacteria are abundant in these reactors. The SRAN reactors were constructed by seeding with nitrifying sludge from an ANSBR and cultivating with ammonium-containing mineral medium (pH 4.0), to which streptomycin at a concentration of 10, 30 and 50 mg L{sup −1} was added. In all reactors, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate in every batch cycle. PCR-aided denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes revealed that some major clones assigned to TM7 bacteria and Gammaproteobacteria were constantly present during the overall period of operation. Fluorescence in situ hybridization (FISH) with specific oligonucleotide probes also showed that TM7 bacteria predominated in all SRAN reactors, accounting for 58% of the total bacterial population on average. Although the biological significance of the TM7 bacteria in the SRAN reactors are unknown, our results suggest that these bacteria are possibly streptomycin-resistant and play some important roles in the acidophilic nitrifying process.

  3. Effect of communities of ammonia-oxidizing bacteria on degradation of 17-alpha-ethynylestradiol by nitrifying activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Limpiyakorn, T.; Sermwaraphan, P.; Kurisu, F.

    2009-07-01

    An endocrine disrupting compound, 17-alpha-ethynylestradiol (EE2), is a synthetic estrogen used as a key ingredient in oral contraceptives pill. this persistent organic pollutant, no biodegradable by most microorganisms, is discharged via municipal waste streams to natural receiving waters. Recently, it was found that ammonia-oxidizing bacteria (AOB) in nitrifying activated sludge (NAS) enriched with high ammonium loads can degrade EE2 via co-metabolism during ammonia oxidation. (Author)

  4. [Effect of Low-concentration Ciprofloxacin on the Nitrification and Nitrifying Microorganisms of Biofilms in Biological Aerated Filter].

    Science.gov (United States)

    He, Shi; Gu, Chao-chao; Wei, Xin; Huang, Sheng-lin; Liu, Zhen-hong; Xue, Gang; Gao, Pin

    2016-04-15

    Effect of low-concentration ciprofloxacin (CIP) on nitrification and nitrifying microorganisms of biofilms was studied in biological aerated filters (BAF). Quantitative PCR (qPCR) was used to determine the abundance variance of four ciprofloxacin resistance genes (CIP-ARGs) during nitrification in biofilms. The correlations between the abundances of CIP-ARGs and nitrifying microorganisms were also discussed. The results showed that CIP had little influence on the ammonium oxidation process of biofilm microorganisms, whereas inhibition of the nitrite oxidation process was found. The quantitative results of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) including Nitrobacter and Nitrospira indicated that the inhibition on the transformation of nitrite was resulted from the inhibition on Nitrobacter and Nitrospira. In addition, little influence of CIP on the relative abundance of aac and qepA in biofilms was found, but the influence on parC and oqxB was great. The abundance of Nitrotacter exhibited significant positive correlation with the abundance of parC. Similar significant correlation was also found between the abundances of Nitrospira and oqxB. It could be speculated that the genetic elements of different nitrifying microorganisms in biofilms possibly carried CIP-ARGs. PMID:27548973

  5. 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 ...

  6. 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

  7. 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

  8. 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...

  9. Signatures of Autotrophic and Heterotrophic Metabolic Activity in Enrichment Cultures from a Sulphur Oxidizing Acid Mine Site

    Science.gov (United States)

    Slater, G. F.; Bernier, L.; Cowie, B. R.; Warren, L. A.

    2006-12-01

    Delineating the role of microorganisms in geochemical processes of interest in natural environments requires the development of tools that provide the ability to distinguish amongst microbial activity associated with different metabolic guilds. The gap between phylogenetic characterization and phenotypic understanding remains, underscoring the need to consider alternative methods. Compound specific analysis of cellular components has the potential to differentiate between active metabolic processes supporting microbial communities and may be especially useful in extreme environments. The goal of this study was to determine whether the phospholipids fatty acid (PLFA) distribution and isotopic signatures associated with autotrophs and heterotrophs enriched from an acid mine drainage (AMD) system differed, and further whether natural consortial autotrophic isolates showed similar signatures to autotrophic pure strains of Acidithiobacillus ferrooxidans and A. thiooxidans. Two distinct initial enrichments with tetrathionate and CO2 yielded primarily autotrophic (95%) Acidithiobaccillus spp. sulphur oxidizing communities. The remaining microbial members of theses enrichments (subculture of the consortial isolates in a medium amended with glucose but without tetrathionate selectively resulted in their visible growth. PLFA profiles and δ13C signatures from autotrophic (1) natural enrichments, pure cultures of (2) A. ferrooxidans and (3) A. thiooxidans were similar, but collectively differed from those of the natural heterotrophic enrichment cultures. The PLFA profiles for the heterotrophic communities were made up of primarily (88-99%) C16:0 and two isomers of C18:1. In contrast, the autotrophic communities had high proportions of C16:1 (up to 18%) as well as cyclo C17 and cyclo C19 PLFA that combined comprised 18 to 58% of the observed PLFA. The δ13C signatures of the PLFA also differed strongly between the two trophic levels. The δ13C of the autotrophic PLFA, - 24 to

  10. Denitrifying bioreactors for nitrate removal from tile drained cropland

    Science.gov (United States)

    Denitrification bioreactors are a promising technology for mitigation of nitrate-nitrogen (NO3-N) losses in subsurface drainage water. Bioreactors are constructed with carbon substrates, typically wood chips, to provide a substrate for denitrifying microorganisms. Researchers in Iowa found that for ...

  11. Sulfur formation and recovery in a thiosulfateoxidizing bioreactor

    NARCIS (Netherlands)

    Gonzalez-Sanchez, A.; Meulepas, R.J.W.; Revah, S.

    2008-01-01

    This work describes the design and Performance of a thiosulfate-oxidizing bioreactor that allowed high elemental sulfur production and recovery efficiency. The reactor system, referred to as a Supernatant-Recycling Settler Bioreactor (SRSB), consisted of a cylindrical upflow reactor and a separate a

  12. Evaluation of woodchip bioreactors for improved water quality

    Science.gov (United States)

    Woodchip bioreactors are gaining popularity with farmers because of their edge-of-field nitrate removal capabilities, which do not require changes in land management practices. However, limited research has been conducted to study the potential of these bioreactors to also reduce downstream transpor...

  13. [Expression of phosphofructokinase gene from Escherichia coli K-12 in obligately autotrophic bacterium Acidithiobacillus thiooxidans].

    Science.gov (United States)

    Tian, Keli; Lin, Jianqun; Liu, Xiangmei; Liu, Ying; Zhang, Changkai

    2003-10-01

    A plasmid pSDK-1 containing the Escherichia coli phosphofructokinase-1 (EC 2.7.1. 11) gene (pfkA) was constructed and transferred into Acidithiobacillus thiooxidans Tt-Z2 by conjugation. The transfer frequency of plasmid from E. coli to Tt-Z2 was 2.6 x 10(-6). More than 68% of Tt-Z2 cells carried the recombinant plasmids after being cultured for 50 generations without selective pressure, which showed that pSDK-1 was maintained consistently in Tt-Z2. The pfkA gene from E. coli could be expressed in this obligately autotrophic bacterium but the enzyme activity (14 U/g was lower than that in E. coli (K-12: 86 U/g; DF1010 carrying plasmid pSDK-1: 97 U/g). In th presence of glucose, the Tt-Z2 transconjugant consumed glucose leading to a better growth yield.

  14. Anaerobic expanded granular sludge bed (EGSB reactor for the removal of sulphide by autotrophic denitrification

    Directory of Open Access Journals (Sweden)

    Carlos Dinamarca

    2014-01-01

    Full Text Available The Removal efficiency, load and N/S molar ratio, of an EGSB reactor for autotrophic sulphide denitrification operated for 96 days, were studied. The reactor was operated at high inlet sulphide concentrations between 0.25 to 3.00 g HS--S/L equivalents to loads between 5 to 250 g HS--S/m3∙h. Sulphide removals higher than 99 % were achieved. At a N/S molar ratio of 0.3 and 12 hours HRT the process was stable even during transition periods of influent sulphide concentration and pH (9.0-12.1. At N/S molar ratio of 1.3, granules lost some of their sedimentation properties and appeared to disintegrate. On average 94 +- 4 % of the equivalent inlet sulphur ended as elemental sulphur.

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

    Science.gov (United States)

    Shcherbakova, Viktoria; Oshurkova, Viktoria; Yoshimura, Yoshitaka

    2015-01-01

    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 M2(T) 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. PMID:27682103

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

    Science.gov (United States)

    Shcherbakova, Viktoria; Oshurkova, Viktoria; Yoshimura, Yoshitaka

    2015-01-01

    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 M2(T) 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.

  17. 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.

  18. STATE OF THE PRACTICE FOR BIOREACTOR LANDFILLS - SUMMARY OF USEPA WORKSHOP ON BIOREACTOR LANDFILLS: SUMMARY

    Science.gov (United States)

    This is a summary of the Workshop on Landfill Bioreactors, held 9/6-7/2000 in Arlington, VA. The purpose of the workshop was to provide a forum to EPA, state and local governments, solid waste industry, and academic research representatives to exchange information and ideas on b...

  19. 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

  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. Disposable bioreactors for inoculum production and protein expression.

    Science.gov (United States)

    Eibl, Regine; Löffelholz, Christian; Eibl, Dieter

    2014-01-01

    Disposable bioreactors have been increasingly implemented over the past ten years. This relates to both R & D and commercial manufacture, in particular, in animal cell-based processes. Among the numerous disposable bioreactors which are available today, wave-mixed bag bioreactors and stirred bioreactors are predominant. Whereas wave-mixed bag bioreactors represent the system of choice for inoculum production, stirred systems are often preferred for protein expression. For this reason, the authors present protocols instructing the reader how to use the wave-mixed BIOSTAT CultiBag RM 20 L for inoculum production and the stirred UniVessel SU 2 L for recombinant protein production at benchtop scale. All methods described are based on a Chinese hamster ovary (CHO) suspension cell line expressing the human placental secreted alkaline phosphatase (SEAP).

  2. Proton translocation during denitrification by a nitrifying--denitrifying Alcaligenes sp.

    Science.gov (United States)

    Castignetti, D; Hollocher, T C

    1983-04-01

    A heterotrophic nitrifying Alcaligenes sp. from soil was grown as a denitrifier on nitrate and subjected to oxidant pulse experiments to ascertain the apparent efficiencies of proton translocations during O2 and nitrogen-oxide respirations. With endogenous substrate as the reducing agent the leads to H+/2e- ratios, extrapolated to zero amount of oxidant per pulse, were 9.4, 3.7, 4.3 and 3.5 for O2, nitrate, nitrite and N2O, respectively. The value for O2 and those for the N-oxides are, respectively, somewhat larger and smaller than corresponding values for Paracoccus denitrificans. None of the three permeant ions employed with the Alcaligenes sp. (valinomycin-K+, thiocyanate and triphenylmethylphosphonium) was ideal for all purposes. Thiocyanate provided highest ratios for O2 but abolished the oxidant pulse response for nitrate and N2O. Valinomycin was slow to penetrate to the cytoplasmic membrane and relatively high concentrations were required for optimal performance. Triphenylmethylphosphonium enhanced passive proton permeability and diminished proton translocation at concentrations required to realize the maximal oxidant pulse response. PMID:6311094

  3. Investigation of Temperature and Influent Load on Nitrifying Wastewater Treatments Using CFD

    Directory of Open Access Journals (Sweden)

    Baharak Sajjadi

    2011-02-01

    Full Text Available The paper describes the effect of temperature, ammonia concentration and feed flow rate on nitrifying treatment of wastewater usage Computational Fluid Dynamics (CFD for two phase bubbly flow in a split cylindrical airlift reactor with a 0.085 m initiator diameter and 0.505 m height. Superficial gas velocity was used as the operational parameter, air was used as the dispersed phase, and wastewater containing ammonia was used as continuous phase. Temperature enhancement in a constant O2 and NH4+ concentrations, resulted the increase of reactions rate also NO2- had an increase of about 3 times as much. By the feed flow rate increase, O2 consumption increase and the rate of NO2- production increase more than NO3- but decrease the reactions efficiency decrease in a constant time. NH4+ concentration enhancement leads to the increase of O2 consumption and better reactions efficiency at higher NH4+ concentration, NO2- concentration increases more. Modeling results are compared with the experimental data. The CFD modeling results show suitable agreement with the experimental data.

  4. Impact of Heavy Metals on Transcriptional and Physiological Activity of Nitrifying Bacteria.

    Science.gov (United States)

    Kapoor, Vikram; Li, Xuan; Elk, Michael; Chandran, Kartik; Impellitteri, Christopher A; Santo Domingo, Jorge W

    2015-11-17

    Heavy metals can inhibit nitrification, a key process for nitrogen removal in wastewater treatment. The transcriptional responses of amoA, hao, nirK, and norB were measured in conjunction with specific oxygen uptake rate (sOUR) for nitrifying enrichment cultures exposed to different metals (Ni(II), Zn(II), Cd(II), and Pb(II)). There was significant decrease in sOUR with increasing concentrations for Ni(II) (0.03-3 mg/L), Zn(II) (0.1-10 mg/L), and Cd(II) (0.03-1 mg/L) (p amoA and hao decreased when exposed to Ni(II) dosages. Slight up-regulation of amoA, hao, and nirK (0.5-1.5-fold) occurred after exposure to 0.3-3 mg/L Zn(II), although their expression decreased for 10 mg/L Zn(II). With the exception of 1000 mg/L Pb(II), stimulation of all genes occurred on Cd(II) and Pb(II) exposure. While overall the results show that RNA-based function-specific assays can be used as potential surrogates for measuring nitrification activity, the degree of inhibition inferred from sOUR and gene transcription is different. We suggest that variations in transcription of functional genes may supplement sOUR based assays as early warning indicators of upsets in nitrification. PMID:26501957

  5. Physiological and transcriptional responses of nitrifying bacteria exposed to copper in activated sludge.

    Science.gov (United States)

    Ouyang, Fan; Zhai, Hongyan; Ji, Min; Zhang, Hongyang; Dong, Zhao

    2016-01-15

    Cu inhibition of gene transcription in ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were rarely studied simultaneously in activated sludge. In this study, the transcription of amoA (for AOB) and nxrB (for NOB), nitrification efficiencies, AOB and NOB respiratory rates, and Cu distribution were simultaneously investigated. Modeling the relationships among the aforementioned parameters revealed that in complex activated sludge systems, nitrification efficiency was an insensitive parameter for showing Cu inhibition. Respiration activities and gene transcription were sensitive to Cu and positively correlated with each other. The transcription of amoA and nxrB genes indicated that the Cu had different inhibitory effects on AOB and NOB. AOB were more susceptible to Cu toxicity than NOB. Moreover, the degree of Cu inhibition on ammonia oxidation was greater than on nitrite oxidation. The analysis and related modeling results indicate that the inhibitory actions of Cu on nitrifying bacteria could mainly be attributed to intracellular Cu. The findings from this study provide insight into the mechanism of Cu inhibition on nitrification in complex activated sludge systems. PMID:26348150

  6. Chronic impact of sulfamethoxazole on the metabolic activity and composition of enriched nitrifying microbial culture.

    Science.gov (United States)

    Katipoglu-Yazan, Tugce; Merlin, Christophe; Pons, Marie-Noëlle; Ubay-Cokgor, Emine; Orhon, Derin

    2016-09-01

    This study investigated the chronic impact of sulfamethoxazole (SMX) on activated sludge sustaining an enriched nitrifying biomass. For this purpose, a laboratory scale fill and draw reactor was operated with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia at a sludge age of 15 days. Additionally, the biomass was exposed to a daily SMX dose of 50 mg/L once the reactor reached steady-state conditions. The reactor performance and microbial composition were monitored for 37 days with conventional parameters and molecular techniques based on the gene for ammonia monooxygenase subunit A (amoA) and the prokaryotic 16S rRNA gene. Denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene cloning analyses suggested a microbial community change concurrent with the addition of SMX. Specifically, quantitative polymerase chain reaction analyses (qPCR/RT-qPCR) revealed a significant reduction in the levels and activity of ammonia oxidizing bacteria (AOB). However, the acclimation period ended with high amoA mRNA levels and improved nitrification efficiency. Partial degradation of SMX by heterotrophic bacteria was also observed. PMID:27235775

  7. Effect of COD/N ratio on nitrogen removal and microbial communities of CANON process in membrane bioreactors.

    Science.gov (United States)

    Zhang, Xiaojing; Zhang, Hongzhong; Ye, Changming; Wei, Mingbao; Du, Jingjing

    2015-08-01

    In this study, the effect of COD/N ratio on completely autotrophic nitrogen removal over nitrite (CANON) process was investigated in five identical membrane bioreactors. The five reactors were simultaneously seeded for 1L CANON sludge and be operated for more than two months under same conditions, with influent COD/N ratio of 0, 0.5, 1, 2 and 4, respectively. DGGE was used to analyze the microbial communities of aerobic ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AAOB) in five reactors. Results revealed the harmonious work of CANON and denitrification with low COD concentration, whereas too high COD concentration suppressed both AOB and AAOB. AOB and AAOB biodiversity both decreased with COD increasing, which then led to worse nitrogen removal. The suppressing threshold of COD/N ratio for CANON was 1.7. CANON was feasible for treating low COD/N sewage, while the high sewage should be converted by anaerobic biogas producing process in advance.

  8. Disposable polymeric cryogel bioreactor matrix for therapeutic protein production.

    Science.gov (United States)

    Jain, Era; Kumar, Ashok

    2013-05-01

    Low cost and high efficiency make disposable bioreactors feasible for small-scale therapeutic development and initial clinical trials. We have developed a cryogel-based disposable bioreactor matrix, which has been used for production of protein therapeutics such as urokinase and monoclonal antibodies (mAbs). The protocol discusses the application of a cryogel bioreactor for mAb production. Cryogels composed of either polyacrylamide (PAAm) coupled to gelatin or semi-interpenetrating PAAm-chitosan are synthesized by free-radical polymerization at -12 °C. Hybridoma cells are immobilized over the cryogel bioreactor and incubated for 48 h. Medium is circulated thereafter at 0.2 ml min(-1) and bioreactors can be run continuously for 60 d. The cryogel-based packed-bed bioreactor can be formulated as a monolith or as beads; it also has an efficiency four times what can be obtained using a tissue-culture flask, a high surface-to-volume ratio and effective nutrient transport. After incubation, the bioreactor setup will take about 60 min using a pre-prepared sterilized cryogel.

  9. Disposable Bioreactors for Plant Micropropagation and Mass Plant Cell Culture

    Science.gov (United States)

    Ducos, Jean-Paul; Terrier, Bénédicte; Courtois, Didier

    Different types of bioreactors are used at Nestlé R&D Centre - Tours for mass propagation of selected plant varieties by somatic embryogenesis and for large scale culture of plants cells to produce metabolites or recombinant proteins. Recent studies have been directed to cut down the production costs of these two processes by developing disposable cell culture systems. Vegetative propagation of elite plant varieties is achieved through somatic embryogenesis in liquid medium. A pilot scale process has recently been set up for the industrial propagation of Coffea canephora (Robusta coffee). The current production capacity is 3.0 million embryos per year. The pre-germination of the embryos was previously conducted by temporary immersion in liquid medium in 10-L glass bioreactors. An improved process has been developed using a 10-L disposable bioreactor consisting of a bag containing a rigid plastic box ('Box-in-Bag' bioreactor), insuring, amongst other advantages, a higher light transmittance to the biomass due to its horizontal design. For large scale cell culture, two novel flexible plastic-based disposable bioreactors have been developed from 10 to 100 L working volumes, validated with several plant species ('Wave and Undertow' and 'Slug Bubble' bioreactors). The advantages and the limits of these new types of bioreactor are discussed, based mainly on our own experience on coffee somatic embryogenesis and mass cell culture of soya and tobacco.

  10. Landfill leachate treatment in assisted landfill bioreactor

    Institute of Scientific and Technical Information of China (English)

    HE Pin-jing; QU Xian; SHAO Li-ming; LEE Duu-jong

    2006-01-01

    Landfill is the major disposal route of municipal solid waste(MSW) in most Asian countries. Leachate from landfill presents a strong wastewater that needs intensive treatment before discharge. Direct recycling was proposed as an effective alternative for leachate treatment by taking the landfill as a bioreactor. This process was proved not only considerably reducing the pollution potential of leachate, but also enhancing organic degradation in the landfill. However, as this paper shows, although direct leachate recycling was effective in landfilled MSW with low food waste fraction (3.5%, w/w), it failed in MSW containing 54% food waste, as normally noted in Asian countries. The initial acid stuck would inhibit methanogenesis to build up, hence strong leachate was yielded from landfill to threaten the quality of receiving water body. We demonstrated the feasibility to use an assisted bioreactor landfill, with a well-decomposed refuse layer as ex-situ anaerobic digester to reducing COD loading in leachate. By doing so, the refuse in simulated landfill column (2.3 m high) could be stabilized in 30 weeks while the COD in leachate reduced by 95%(61000 mg/L to 3000 mg/L). Meanwhile, the biogas production was considerably enhanced, signaling by the much greater amount and much higher methane content in the biogas.

  11. MEMBRANE BIOREACTOR FOR TREATMENT OF RECALCITRANT WASTEWATERS

    Directory of Open Access Journals (Sweden)

    Suprihatin Suprihatin

    2012-02-01

    Full Text Available The low biodegradable wastewaters remain a challenge in wastewater treatment technology. The performance of membrane bioreactor systems with submerged hollow fiber micro- and ultrafiltration membrane modules were examined for purifying recalcitrant wastewaters of leachate of a municipal solid waste open dumping site and effluent of pulp and paper mill. The use of MF and UF membrane bioreactor systems showed an efficient treatment for both types wastewaters with COD reduction of 80-90%. The membrane process achieved the desirable effects of maintaining reasonably high biomass concentration and long sludge retention time, while producing a colloid or particle free effluent. For pulp and paper mill effluent a specific sludge production of 0.11 kg MLSS/kg COD removed was achieved. A permeate flux of about 5 L/m²h could be achieved with the submerged microfiltration membrane. Experiments using ultrafiltration membrane produced relatively low permeate fluxes of 2 L/m²h. By applying periodical backwash, the flux could be improved significantly. It was indicated that the particle or colloid deposition on membrane surface was suppressed by backwash, but reformation of deposit was not effectively be prevented by shear-rate effect of aeration. Particle and colloid started to accumulate soon after backwash. Construction of membrane module and operation mode played a critical role in achieving the effectiveness of aeration in minimizing deposit formation on the membrane surface.

  12. Membrane bioreactor for drinking water denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Barreiros, A.M. [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa (Portugal)]|[Escola Superior de Tecnologia, Instituto Politecnico de Setubal, Rua do Vale de Chaves, Estefanilha, 2900 Setubal (Portugal); Rodrigues, C.M.; Crespo, J.P.S.G.; Reis, M.A.M. [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa (Portugal)

    1998-04-01

    The aim of this study is to evaluate the performance of a membrane bioreactor with cell recycle to be used for drinking water denitrification, when operated with a high nitrate load (up to 7.68 kgNO{sub 3}{sup -}/m{sup 3} day) and low hydraulic retention time (down to 0.625 h). Nitrate and nitrite were always completely removed for all the operational conditions used. The effluent`s nitrite concentration kept below 0.1 mg NO{sub 2}{sup -}/l with exception of a short period, during the reactor start-up, when it accumulates. The performance of the membrane bioreactor was also evaluated using a groundwater containing 148 mg NO{sub 3}{sup -}/l. Nitrate and nitrite concentration in the effluent were below the recommended values for drinking water when the reactor was controlled at pH 7.0. The membrane flux decreases during operation as a consequence of membrane fouling. The flux decrease was more severe during operation with synthetic medium than with contaminated groundwater due to the existence of molecular complexes in the synthetic broth. A backshock technique was used to reduce the surface fouling of the membrane. Combining this technique with the use of a reserve asymmetric structured membrane it was found that the membrane flux remains nearly unchanged. (orig.) With 7 figs., 14 refs.

  13. Novel Hydrogen Bioreactor and Detection Apparatus.

    Science.gov (United States)

    Rollin, Joseph A; Ye, Xinhao; Del Campo, Julia Martin; Adams, Michael W W; Zhang, Y-H Percival

    2016-01-01

    In vitro hydrogen generation represents a clear opportunity for novel bioreactor and system design. Hydrogen, already a globally important commodity chemical, has the potential to become the dominant transportation fuel of the future. Technologies such as in vitro synthetic pathway biotransformation (SyPaB)-the use of more than 10 purified enzymes to catalyze unnatural catabolic pathways-enable the storage of hydrogen in the form of carbohydrates. Biohydrogen production from local carbohydrate resources offers a solution to the most pressing challenges to vehicular and bioenergy uses: small-size distributed production, minimization of CO2 emissions, and potential low cost, driven by high yield and volumetric productivity. In this study, we introduce a novel bioreactor that provides the oxygen-free gas phase necessary for enzymatic hydrogen generation while regulating temperature and reactor volume. A variety of techniques are currently used for laboratory detection of biohydrogen, but the most information is provided by a continuous low-cost hydrogen sensor. Most such systems currently use electrolysis for calibration; here an alternative method, flow calibration, is introduced. This system is further demonstrated here with the conversion of glucose to hydrogen at a high rate, and the production of hydrogen from glucose 6-phosphate at a greatly increased reaction rate, 157 mmol/L/h at 60 °C. PMID:25022362

  14. Landfill leachate treatment in assisted landfill bioreactor.

    Science.gov (United States)

    He, Pin-Jing; Qu, Xian; Shao, Li-Ming; Lee, Duu-Jong

    2006-01-01

    Landfill is the major disposal route of municipal solid waste (MSW) in most Asian countries. Leachate from landfill presents a strong wastewater that needs intensive treatment before discharge. Direct recycling was proposed as an effective alternative for leachate treatment by taking the landfill as a bioreactor. This process was proved not only considerably reducing the pollution potential of leachate, but also enhancing organic degradation in the landfill. However, as this paper shows, although direct leachate recycling was effective in landfilled MSW with low food waste fraction (3.5%, w/w), it failed in MSW containing 54% food waste, as normally noted in Asian countries. The initial acid stuck would inhibit methanogenesis to build up, hence strong leachate was yielded from landfill to threaten the quality of receiving water body. We demonstrated the feasibility to use an assisted bioreactor landfill, with a well-decomposed refuse layer as ex-situ anaerobic digester to reducing COD loading in leachate. By doing so, the refuse in simulated landfill column (2.3 m high) could be stabilized in 30 weeks while the COD in leachate reduced by 95% (61000 mg/L to 3000 mg/L). Meanwhile, the biogas production was considerably enhanced, signaling by the much greater amount and much higher methane content in the biogas. PMID:20050569

  15. LTCC based bioreactors for cell cultivation

    Science.gov (United States)

    Bartsch, H.; Welker, T.; Welker, K.; Witte, H.; Müller, J.

    2016-01-01

    LTCC multilayers offer a wide range of structural options and flexibility of connections not available in standard thin film technology. Therefore they are considered as material base for cell culture reactors. The integration of microfluidic handling systems and features for optical and electrical capturing of indicators for cell culture growth offers the platform for an open system concept. The present paper assesses different approaches for the creation of microfluidic channels in LTCC multilayers. Basic functions required for the fluid management in bioreactors include temperature and flow control. Both features can be realized with integrated heaters and temperature sensors in LTCC multilayers. Technological conditions for the integration of such elements into bioreactors are analysed. The temperature regulation for the system makes use of NTC thermistor sensors which serve as real value input for the control of the heater. It allows the adjustment of the fluid temperature with an accuracy of 0.2 K. The tempered fluid flows through the cell culture chamber. Inside of this chamber a thick film electrode array monitors the impedance as an indicator for the growth process of 3-dimensional cell cultures. At the system output a flow sensor is arranged to monitor the continual flow. For this purpose a calorimetric sensor is implemented, and its crucial design parameters are discussed. Thus, the work presented gives an overview on the current status of LTCC based fluid management for cell culture reactors, which provides a promising base for the automation of cell culture processes.

  16. Novel Hydrogen Bioreactor and Detection Apparatus.

    Science.gov (United States)

    Rollin, Joseph A; Ye, Xinhao; Del Campo, Julia Martin; Adams, Michael W W; Zhang, Y-H Percival

    2016-01-01

    In vitro hydrogen generation represents a clear opportunity for novel bioreactor and system design. Hydrogen, already a globally important commodity chemical, has the potential to become the dominant transportation fuel of the future. Technologies such as in vitro synthetic pathway biotransformation (SyPaB)-the use of more than 10 purified enzymes to catalyze unnatural catabolic pathways-enable the storage of hydrogen in the form of carbohydrates. Biohydrogen production from local carbohydrate resources offers a solution to the most pressing challenges to vehicular and bioenergy uses: small-size distributed production, minimization of CO2 emissions, and potential low cost, driven by high yield and volumetric productivity. In this study, we introduce a novel bioreactor that provides the oxygen-free gas phase necessary for enzymatic hydrogen generation while regulating temperature and reactor volume. A variety of techniques are currently used for laboratory detection of biohydrogen, but the most information is provided by a continuous low-cost hydrogen sensor. Most such systems currently use electrolysis for calibration; here an alternative method, flow calibration, is introduced. This system is further demonstrated here with the conversion of glucose to hydrogen at a high rate, and the production of hydrogen from glucose 6-phosphate at a greatly increased reaction rate, 157 mmol/L/h at 60 °C.

  17. 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

  18. Negative Effects of Sludge Bulking in Membrane Bio-Reactor

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying; HUANG Zhi; REN Nanqi; MENG Qingjuan

    2006-01-01

    Sludge bulking property of membrane bio-reactor was investigated in this study through contrast research. When the sludge bulking appeared, the removal efficiency of COD in membrane bio-reactor increased slightly through the function of filamentous bacteria. However, the negative effects of the higher net water-head differential pressures, the high block rate of membrane pore and the great quantity of filamentous bacteria at the external surface presented at the same time. Thus, plenty of methods should be performed to control sludge bulking once it happened in membrane bio-reactor.

  19. Efficient red-emission InGaN/GaN multilayered structure on Si with surface-nitrified HfO{sub 2} film as buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei; Zhang, Xuehua; Hu, Fangren [Nanjing University of Posts and Telecommunications, School of Optoelectronic Engineering, Nanjing (China); Nanjing University of Posts and Telecommunications, Peter Grunberg Research Center, Nanjing (China); Wang, Yongjin [Nanjing University of Posts and Telecommunications, Peter Grunberg Research Center, Nanjing (China); Hane, K. [Tohoku University, Department of Nanomechanics, Sendai (Japan)

    2016-03-15

    A four-period InGaN/GaN (8 nm/48 nm) layered structure was deposited on a Si substrate with a surface-nitrified HfO{sub 2} film as a buffer layer (5 nm). A high In concentration of In{sub 0.36}Ga{sub 0.64}N was obtained in the InGaN layers. Red photoluminescence of 648 nm was observed from the layered structure. The internal quantum efficiency of the red emission from the InGaN layers on the surface-nitrified HfO{sub 2}/Si was 52 %, which was more than 18 times larger than that on the Si substrate without HfO{sub 2}. The surface-nitrified HfO{sub 2} provides another effective buffer layer to grow the InGaN/GaN layered structure on the Si substrate. (orig.)

  20. Efficient red-emission InGaN/GaN multilayered structure on Si with surface-nitrified HfO2 film as buffer layer

    International Nuclear Information System (INIS)

    A four-period InGaN/GaN (8 nm/48 nm) layered structure was deposited on a Si substrate with a surface-nitrified HfO2 film as a buffer layer (5 nm). A high In concentration of In0.36Ga0.64N was obtained in the InGaN layers. Red photoluminescence of 648 nm was observed from the layered structure. The internal quantum efficiency of the red emission from the InGaN layers on the surface-nitrified HfO2/Si was 52 %, which was more than 18 times larger than that on the Si substrate without HfO2. The surface-nitrified HfO2 provides another effective buffer layer to grow the InGaN/GaN layered structure on the Si substrate. (orig.)

  1. Biofilm Thickness Influences Biodiversity in Nitrifying MBBRs-Implications on Micropollutant Removal.

    Science.gov (United States)

    Torresi, Elena; Fowler, S Jane; Polesel, Fabio; Bester, Kai; Andersen, Henrik R; Smets, Barth F; Plósz, Benedek Gy; Christensson, Magnus

    2016-09-01

    In biofilm systems for wastewater treatment (e.g., moving bed biofilms reactors-MBBRs) biofilm thickness is typically not under direct control. Nevertheless, biofilm thickness is likely to have a profound effect on the microbial diversity and activity, as a result of diffusion limitation and thus substrate penetration in the biofilm. In this study, we investigated the impact of biofilm thickness on nitrification and on the removal of more than 20 organic micropollutants in laboratory-scale nitrifying MBBRs. We used novel carriers (Z-carriers, AnoxKaldnes) that allowed controlling biofilm thickness at 50, 200, 300, 400, and 500 μm. The impact of biofilm thickness on microbial community was assessed via 16S rRNA gene amplicon sequencing and ammonia monooxygenase (amoA) abundance quantification through quantitative PCR (qPCR). Results from batch experiments and microbial analysis showed that (i) the thickest biofilm (500 μm) presented the highest specific biotransformation rate constants (kbio, L g(-1) d(-1)) for 14 out of 22 micropollutants; (ii) biofilm thickness positively associated with biodiversity, which was suggested as the main factor for the observed enhancement of kbio; (iii) the thinnest biofilm (50 μm) exhibited the highest nitrification rate (gN d(-1) g(-1)), amoA gene abundance and kbio values for some of the most recalcitrant micropollutants (i.e., diclofenac and targeted sulfonamides). Although thin biofilms favored nitrification activity and the removal of some micropollutants, treatment systems based on thicker biofilms should be considered to enhance the elimination of a broad spectrum of micropollutants. PMID:27477857

  2. [Distribution Characteristics of Nitrifiers and Denitrifiers in the River Sediments of Tongling City].

    Science.gov (United States)

    Cheng, Jian-hua; Dou, Zhi-yong; Sun, Qing-ye

    2016-04-15

    Rivers in mining areas were influenced by contaminants such as nitrogen, phosphorus and organic matter due to domestic and agricultural wastewater discharge in addition to pollutants caused by mining activities. In this study, surface sediment samples of rivers in Tongling city were collected to address the effect of season and pollution type on the abundance of nitrifiers and denitrifiers using quantitative polymerase chain reaction (QPCR) technique targeting at the ammonia monooxygenase (amoA) and nitrite reductase (nir) genes. The results showed that the average ahundance of ammonia oxidizing archaea (AGA) (ranging from 1.74 x 10⁵ to 1.45 x 10⁸ copies · g⁻¹) was 4.39 times that of ammonia oxidizing hacteria (AGH) (ranging from 1.39 x 10⁵ to 3.39 x 10⁷ copies · g⁻¹); and the average abundance of nirK gene (ranging from 4.45 x 10⁶ to 1.51 x 10⁸ copies · g) was almost a thirtieth part of nirS gene (ranging from 1.69 x 10⁷ to 8.55 x 10⁹ copies · g⁻¹). The abundance of AOA was higher in spring and autumn, and lower in summer and winter. And sediment AOB abundance was higher in spring and winter than in summer and autumn. Meanwhile, the abundance of nir genes was in the order of spring (nirS )/autumn (nirK) > summer > winter > autumn (nirS )/spring (nirK). Moreover, the abundance of bacterial and archaeal arnoA and nirS genes in sediments influenced by mine pollution was generally higher than that in sediments influenced by agricultural non-point pollution, whereas the abundance of nirK gene showed an opposite trend. PMID:27548957

  3. Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils.

    Science.gov (United States)

    Pajares, Silvia; Bohannan, Brendan J M

    2016-01-01

    Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research. PMID:27468277

  4. Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils

    Science.gov (United States)

    Pajares, Silvia; Bohannan, Brendan J. M.

    2016-01-01

    Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research. PMID:27468277

  5. 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...... continuous aeration, could remove more than 5.5 g N/m2/day (at loads up to 8 g N/m2/day) by controlled variation of sequential aeration regimes. Daily averaged ratios of the surficial loads of O2 (oxygen) to NH4+ (ammonium) (LO2/LNH4) were close to 1.73 at this optimum. Real-time quantitative PCR based on 16...

  6. Mechanobiologic Research in a Microgravity Environment Bioreactor

    Science.gov (United States)

    Guidi, A.; Dubini, G.; Tominetti, F.; Raimondi, M.

    A current problem in tissue culturing technology is the unavailability of an effective Bioreactor for the in vitro cultivation of cells and explants. It has, in fact, proved extremely difficult to promote the high-density three-dimensional in vitro growth of human tissues that have been removed from the body and deprived of their normal in vivo vascular sources of nutrients and gas exchange. A variety of tissue explants can be maintained for a short period of time on a supportive collagen matrix surrounded by culture medium. But this system provides only limited mass transfer of nutrients and wastes through the tissue, and gravity-induced sedimentation prevents complete three- dimensional cell-cell and cell-matrix interactions. Several devices presently on the market have been used with only limited success since each has limitations, which restrict usefulness and versatility. Further, no Bioreactor or culture vessel is known that will allow for unimpeded growth of three dimensional cellular aggregates or tissue. Extensive research on the effect of mechanical stimuli on cell metabolism suggests that tissues may respond to mechanical stimulation via loading-induced flow of the interstitial fluids. During the culture, cells are subject to a flow of culture medium. Flow properties such as flow field, flow regime (e.g. turbulent or laminar), flow pattern (e.g. circular), entity and distribution of the shear stress acting on the cells greatly influence fundamental aspects of cell function, such as regulation and gene expression. This has been demonstrated for endothelial cells and significant research efforts are underway to elucidate these mechanisms in various other biological systems. Local fluid dynamics is also responsible of the mass transfer of nutrients and catabolites as well as oxygenation through the tissue. Most of the attempts to culture tissue-engineered constructs in vitro have utilized either stationary cultures or systems generating relatively small

  7. The response of nitrifying microbial assemblages to ammonium (NH4+) enrichment from salmon farm activities in a northern Chilean Fjord

    Science.gov (United States)

    Elizondo-Patrone, Claudia; Hernández, Klaudia; Yannicelli, Beatriz; Olsen, Lasse Mork; Molina, Verónica

    2015-12-01

    The consequences of aquaculture include alterations in nitrogen cycling in aquatic environments that may lead to ecosystem degradation. Herein salmon aquaculture release of ammonium (NH4+) to the water column and its effects on natural archaea and bacteria ammonia-oxidizers (AOA and AOB) and nitrite-oxidizing bacteria (NOB) community structure were studied in the Comau fjord using molecular approaches, such as: cloning (AOA and AOB richness), qPCR for C. Nitrosopumilus maritimus (AOA) and Nitrospina sp. (NOB) abundance (DNA) and RT-qPCR only for Nitrospina sp activity (RNA). Sampling was carried out in brackish (0.7-25 salinity, 30 salinity, 25 m depth) waters during contrasting salmon production periods: rest (winter 2012), growth and harvest (summer and winter 2013). During the rest period, the highest NH4+ concentration was observed at Vodudahue River, whereas during productive periods NH4+ accumulated in the brackish layer inside salmon cages and in the vicinty (up to 700 m distance from the cages). The nitrifier community from the fjord reference station (Stn-C) was characterized by C. N. maritimus (AOA) and Nitrosomonas sp. (AOB) sequences affiliated with cosmopolitan ecotypes (e.g., marine, freshwater, hydrothermal), maxima abundances of C. N. maritimus (AOA) and Nitrospina sp. and extreme ranges of Nitrospina sp. activity occurred in the brackish layer. During productive periods, abundances of C. N. maritimus were co-varied with NH4+ concentrations inside salmon cages (summer) and the adjacent areas (winter). Productive periods were characterized by lower abundances but more homogeneity between brackish and marine areas than for the Stn-C nitrifiers. The physiological state of Nitrospina sp. estimated from cDNA:DNA ratios indicated higher growth during winter 2013 associated with NH4+ enrichment derived from production and river input. Our results suggest that in Comau Fjord, NH4+ enrichment events occur during salmon production and also naturally by river

  8. Bioreactors Drive Advances in Tissue Engineering

    Science.gov (United States)

    2012-01-01

    It was an unlikely moment for inspiration. Engineers David Wolf and Ray Schwarz stopped by their lab around midday. Wolf, of Johnson Space Center, and Schwarz, with NASA contractor Krug Life Sciences (now Wyle Laboratories Inc.), were part of a team tasked with developing a unique technology with the potential to enhance medical research. But that wasn t the focus at the moment: The pair was rounding up colleagues interested in grabbing some lunch. One of the lab s other Krug engineers, Tinh Trinh, was doing something that made Wolf forget about food. Trinh was toying with an electric drill. He had stuck the barrel of a syringe on the bit; it spun with a high-pitched whirr when he squeezed the drill s trigger. At the time, a multidisciplinary team of engineers and biologists including Wolf, Schwarz, Trinh, and project manager Charles D. Anderson, who formerly led the recovery of the Apollo capsules after splashdown and now worked for Krug was pursuing the development of a technology called a bioreactor, a cylindrical device used to culture human cells. The team s immediate goal was to grow human kidney cells to produce erythropoietin, a hormone that regulates red blood cell production and can be used to treat anemia. But there was a major barrier to the technology s success: Moving the liquid growth media to keep it from stagnating resulted in turbulent conditions that damaged the delicate cells, causing them to quickly die. The team was looking forward to testing the bioreactor in space, hoping the device would perform more effectively in microgravity. But on January 28, 1986, the Space Shuttle Challenger broke apart shortly after launch, killing its seven crewmembers. The subsequent grounding of the shuttle fleet had left researchers with no access to space, and thus no way to study the effects of microgravity on human cells. As Wolf looked from Trinh s syringe-capped drill to where the bioreactor sat on a workbench, he suddenly saw a possible solution to both

  9. 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

  10. 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.

  11. 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

  12. A study of autotrophic communities in two Victoria Land lakes (Continental Antarctica using photosynthetic pigments

    Directory of Open Access Journals (Sweden)

    Roberto BARGAGLI

    2010-08-01

    Full Text Available The composition of algal pigments and extracellular polymeric substances (EPS was determined in microbial mats from two lakes in Victoria Land (Continental Antarctica with different lithology and environmental features. The aim was to expand knowledge of benthic autotrophic communities in Antarctic lacustrine ecosystems, providing reference data for future assessment of possible changes in environmental conditions and freshwater communities. The results of chemical analyses were supported by microscopy observations. Pigment profiles showed that filamentous cyanobacteria are dominant in both lakes. Samples from the water body at Edmonson Point had greater biodiversity, fewer pigments and lower EPS ratios than those from the lake at Kar Plateau. Differences in mat composition and in pigment and EPS profile between the two lakes are discussed in terms of local environmental conditions such as lithology, ice-cover and UV radiation. The present study suggests that a chemical approach could be useful in the study of benthic communities in Antarctic lakes and their variations in space and time.

  13. EMERGING TECHNOLOGY BULLETIN - METHANOTROPHIC BIOREACTOR SYSTEM - BIOTROL, INC.

    Science.gov (United States)

    BioTrol's Methanotrophic Bioreactor is an above-ground remedial system for water contaminated with halogenated volatile organic compounds, including trichloroethylene (ICE) and related chemicals. Its design features circumvent problems peculiar to treatment of this unique class o...

  14. Production of monoclonal antibody with Celline-350 bioreactor

    International Nuclear Information System (INIS)

    Monoclonal antibodies are protein that are highly specific and sensitive in their reaction with specific sites on target molecules that they have become reagents of central importance in the diagnostic and treatment of human diseases. This paper reports the use of CELLine-350 bioreactor to produce continuous supply of serum-free breast cancer monoclonal antibody. Initial volume of 5ml (1.5 x 106 viable cells/ml) is inoculated into the bioreactor and harvesting is done every 5 days to obtain high yield monoclonal antibody. The serum-free supernatant is precipitated with 50% saturated ammonia sulfate and the antibody is purified by protein-G affinity chromatography. The concentration of monoclonal antibody successfully produced by the bioreactor is 0.91mg/ml respectively and it is measured by the Lowry method. This result shows that bioreactor Celline-350 is easy to handle and cost effective for the continuous production of serum free monoclonal antibody. (Author)

  15. The Potential for Microalgae as Bioreactors to Produce Pharmaceuticals

    Science.gov (United States)

    Yan, Na; Fan, Chengming; Chen, Yuhong; Hu, Zanmin

    2016-01-01

    As photosynthetic organisms, microalgae can efficiently convert solar energy into biomass. Microalgae are currently used as an important source of valuable natural biologically active molecules, such as carotenoids, chlorophyll, long-chain polyunsaturated fatty acids, phycobiliproteins, carotenoids and enzymes. Significant advances have been achieved in microalgae biotechnology over the last decade, and the use of microalgae as bioreactors for expressing recombinant proteins is receiving increased interest. Compared with the bioreactor systems that are currently in use, microalgae may be an attractive alternative for the production of pharmaceuticals, recombinant proteins and other valuable products. Products synthesized via the genetic engineering of microalgae include vaccines, antibodies, enzymes, blood-clotting factors, immune regulators, growth factors, hormones, and other valuable products, such as the anticancer agent Taxol. In this paper, we briefly compare the currently used bioreactor systems, summarize the progress in genetic engineering of microalgae, and discuss the potential for microalgae as bioreactors to produce pharmaceuticals. PMID:27322258

  16. Hairy root culture: bioreactor design and process intensification.

    Science.gov (United States)

    Stiles, Amanda R; Liu, Chun-Zhao

    2013-01-01

    The cultivation of hairy roots for the production of secondary metabolites offers numerous advantages; hairy roots have a fast growth rate, are genetically stable, and are relatively simple to maintain in phytohormone free media. Hairy roots provide a continuous source of secondary metabolites, and are useful for the production of chemicals for pharmaceuticals, cosmetics, and food additives. In order for hairy roots to be utilized on a commercial scale, it is necessary to scale-up their production. Over the last several decades, significant research has been conducted on the cultivation of hairy roots in various types of bioreactor systems. In this review, we discuss the advantages and disadvantages of various bioreactor systems, the major factors related to large-scale bioreactor cultures, process intensification technologies and overview the mathematical models and computer-aided methods that have been utilized for bioreactor design and development.

  17. Bioreactor activated graft material for early implant fixation in bone

    DEFF Research Database (Denmark)

    Snoek Henriksen, Susan; Ding, Ming; Overgaard, Søren

    2011-01-01

    Introduction The combined incubation of a composite scaffold with bone marrow stromal cells in a perfusion bioreactor could make up a novel hybrid graft material with optimal properties for early fixation of implant to bone. The aim of this study was to create a bioreactor activated graft (BAG......) material, which could induce early implant fixation similar to that of allograft. Two porous scaffold materials incubated with cells in a perfusion bioreactor were tested in this study. Methods and Materials Two groups of 8 skeletally mature female sheep were anaesthetized before aspiration of bone marrow...... from the iliac crest. For both groups, mononuclear cells were isolated, and injected into a perfusion bioreactor (Millenium Biologix AG, Switzerland). Scaffold granules (Ø~900-1500 µm, ~88% porosity) in group 1, consisted of hydroxyapatite (HA, 70%) with β-tricalcium-phosphate (β-TCP, 30%) (Danish...

  18. Modelling across bioreactor scales: methods, challenges and limitations

    DEFF Research Database (Denmark)

    Gernaey, Krist

    Scale-up and scale-down of bioreactors are very important in industrial biotechnology, especially with the currently available knowledge on the occurrence of gradients in industrial-scale bioreactors. Moreover, it becomes increasingly appealing to model such industrial scale systems, considering...... that it is challenging and expensive to acquire experimental data of good quality that can be used for characterizing gradients occurring inside a large industrial scale bioreactor. But which model building methods are available? And how can one ensure that the parameters in such a model are properly estimated? And what...... are the limitations of different types of mod - els? This paper will provide examples of models that have been published in the literature for use across bioreactor scales, including computational fluid dynamics (CFD) and population balance models. Furthermore, the importance of good modeling practice...

  19. Upflow bioreactor with septum and pressure release mechanism

    Science.gov (United States)

    Hansen, Conly L.; Hansen, Carl S.; Pack, Kevin; Milligan, John; Benefiel, Bradley C.; Tolman, C. Wayne; Tolman, Kenneth W.

    2010-04-20

    An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes means for releasing pressure buildup in the lower chamber. In one configuration, the septum includes a releasable portion having an open position and a closed position. The releasable portion is configured to move to the open position in response to pressure buildup in the lower chamber. In the open position fluid communication between the lower chamber and the upper chamber is increased. Alternatively the lower chamber can include a pressure release line that is selectively actuated by pressure buildup. The pressure release mechanism can prevent the bioreactor from plugging and/or prevent catastrophic damage to the bioreactor caused by high pressures.

  20. The Potential for Microalgae as Bioreactors to Produce Pharmaceuticals.

    Science.gov (United States)

    Yan, Na; Fan, Chengming; Chen, Yuhong; Hu, Zanmin

    2016-01-01

    As photosynthetic organisms, microalgae can efficiently convert solar energy into biomass. Microalgae are currently used as an important source of valuable natural biologically active molecules, such as carotenoids, chlorophyll, long-chain polyunsaturated fatty acids, phycobiliproteins, carotenoids and enzymes. Significant advances have been achieved in microalgae biotechnology over the last decade, and the use of microalgae as bioreactors for expressing recombinant proteins is receiving increased interest. Compared with the bioreactor systems that are currently in use, microalgae may be an attractive alternative for the production of pharmaceuticals, recombinant proteins and other valuable products. Products synthesized via the genetic engineering of microalgae include vaccines, antibodies, enzymes, blood-clotting factors, immune regulators, growth factors, hormones, and other valuable products, such as the anticancer agent Taxol. In this paper, we briefly compare the currently used bioreactor systems, summarize the progress in genetic engineering of microalgae, and discuss the potential for microalgae as bioreactors to produce pharmaceuticals. PMID:27322258

  1. Hairy root culture: bioreactor design and process intensification.

    Science.gov (United States)

    Stiles, Amanda R; Liu, Chun-Zhao

    2013-01-01

    The cultivation of hairy roots for the production of secondary metabolites offers numerous advantages; hairy roots have a fast growth rate, are genetically stable, and are relatively simple to maintain in phytohormone free media. Hairy roots provide a continuous source of secondary metabolites, and are useful for the production of chemicals for pharmaceuticals, cosmetics, and food additives. In order for hairy roots to be utilized on a commercial scale, it is necessary to scale-up their production. Over the last several decades, significant research has been conducted on the cultivation of hairy roots in various types of bioreactor systems. In this review, we discuss the advantages and disadvantages of various bioreactor systems, the major factors related to large-scale bioreactor cultures, process intensification technologies and overview the mathematical models and computer-aided methods that have been utilized for bioreactor design and development. PMID:23604206

  2. Microbial Bioreactor Development in the ALS NSCORT

    Science.gov (United States)

    Mitchell, Cary; Whitaker, Dawn; Banks, M. Katherine; Heber, Albert J.; Turco, Ronald F.; Nies, Loring F.; Alleman, James E.; Sharvelle, Sybil E.; Li, Congna; Heller, Megan

    The NASA Specialized Center of Research and Training in Advanced Life Support (the ALS NSCORT), a partnership of Alabama A & M, Howard, and Purdue Universities, was established by NASA in 2002 to develop technologies that will reduce the Equivalent System Mass (ESM) of regenerative processes within future space life-support systems. A key focus area of NSCORT research has been the development of efficient microbial bioreactors for treatment of human, crop, and food-process wastes while enabling resource recovery. The approach emphasizes optimizing the energy-saving advantages of hydrolytic enzymes for biomass degradation, with focus on treatment of solid wastes including crop residue, paper, food, and human metabolic wastes, treatment of greywater, cabin air, off-gases from other treatment systems, and habitat condensate. This summary includes important findings from those projects, status of technology development, and recommendations for next steps. The Plant-based Anaerobic-Aerobic Bioreactor-Linked Operation (PAABLO) system was developed to reduce crop residue while generating energy and/or food. Plant residues initially were added directly to the bioreactor, and recalcitrant residue was used as a substrate for growing plants or mushrooms. Subsequently, crop residue was first pretreated with fungi to hydrolyze polymers recalcitrant to bacteria, and leachate from the fungal beds was directed to the anaerobic digester. Exoenzymes from the fungi pre-soften fibrous plant materials, improving recovery of materials that are more easily biodegraded to methane that can be used for energy reclamation. An Autothermal Thermophilic Aerobic Digestion (ATAD) system was developed for biodegradable solid wastes. Objectives were to increase water and nutrient recovery, reduce waste volume, and inactivate pathogens. Operational parameters of the reactor were optimized for degradation and resource recovery while minimizing system requirements and footprint. The start-up behavior

  3. Vortex breakdown in a truncated conical bioreactor

    Science.gov (United States)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.; Shtern, Vladimir N.

    2015-12-01

    This numerical study explains the eddy formation and disappearance in a slow steady axisymmetric air-water flow in a vertical truncated conical container, driven by the rotating top disk. Numerous topological metamorphoses occur as the water height, Hw, and the bottom-sidewall angle, α, vary. It is found that the sidewall convergence (divergence) from the top to the bottom stimulates (suppresses) the development of vortex breakdown (VB) in both water and air. At α = 60°, the flow topology changes eighteen times as Hw varies. The changes are due to (a) competing effects of AMF (the air meridional flow) and swirl, which drive meridional motions of opposite directions in water, and (b) feedback of water flow on AMF. For small Hw, the AMF effect dominates. As Hw increases, the swirl effect dominates and causes VB. The water flow feedback produces and modifies air eddies. The results are of fundamental interest and can be relevant for aerial bioreactors.

  4. Robust Control Methods for a Recycle Bioreactor

    Directory of Open Access Journals (Sweden)

    Cosmin IONETE

    2001-12-01

    Full Text Available The paper presents a robust control design strategy for bioprocesses, which are characterized by strongly nonlinear dynamics. More precisely, we present the H2 methodology in order to compute the controller for a recycle Continuous Stirred Tank Bioreactor (CSTB. We consider a general method of formulating control problem, which makes use of linear fractional transformation as introduced by Doyle (1978. The formulation makes use of the general two-port configuration of the generalized plant with a generalized controller. The H2 norm is the quadratic criterion used in optimal control as LQG. The overall control objective is to minimize the H2 norm of the transfer matrix function from the weighted exogenous inputs to the weighted controlled outputs. The advantage of H2 control technique, which uses the linearized model of the CSTB, is that it is completely automated and very flexible. Finally, we prove that the closed loop control structure has very good inner robustness.

  5. Start-up Strategy for Continuous Bioreactors

    Directory of Open Access Journals (Sweden)

    A.C. da Costa

    1997-06-01

    Full Text Available Abstract - The start-up of continuous bioreactors is solved as an optimal control problem. The choice of the dilution rate as the control variable reduces the dimension of the system by making the use of the global balance equation unnecessary for the solution of the optimization problem. Therefore, for systems described by four or less mass balance equations, it is always possible to obtain an analytical expression for the singular arc as a function of only the state variables. The steady state conditions are shown to satisfy the singular arc expression and, based on this knowledge, a feeding strategy is proposed which leads the reactor from an initial state to the steady state of maximum productivity

  6. Comparative study of emerging micropollutants removal by aerobic activated sludge of large laboratory-scale membrane bioreactors and sequencing batch reactors under low-temperature conditions.

    Science.gov (United States)

    Kruglova, Antonina; Kråkström, Matilda; Riska, Mats; Mikola, Anna; Rantanen, Pirjo; Vahala, Riku; Kronberg, Leif

    2016-08-01

    Four emerging micropollutants ibuprofen, diclofenac, estrone (E1) and 17α-ethinylestradiol (EE2) were studied in large laboratory-scale wastewater treatment plants (WWTPs) with high nitrifying activity. Activated sludge (AS) with sludge retention times (SRTs) of 12days and 14days in sequencing batch reactors (SBRs) and 30days, 60days and 90days in membrane bioreactors (MBRs) were examined at 8°C and 12°C. Concentrations of pharmaceuticals and their main metabolites were analysed in liquid phase and solid phase of AS by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A remarkable amount of contaminants were detected in solids of AS, meaning the accumulation of micropollutants in bacterial cells. The biodegradation rate constants (Kbiol) were affected by SRT and temperature. MBR with a 90-day SRT showed the best results of removal. Conventional SBR process was inefficient at 8°C showing Kbiol values lower than 0.5lgSS(-1)d(-1) for studied micropollutants.

  7. Comparative study of emerging micropollutants removal by aerobic activated sludge of large laboratory-scale membrane bioreactors and sequencing batch reactors under low-temperature conditions.

    Science.gov (United States)

    Kruglova, Antonina; Kråkström, Matilda; Riska, Mats; Mikola, Anna; Rantanen, Pirjo; Vahala, Riku; Kronberg, Leif

    2016-08-01

    Four emerging micropollutants ibuprofen, diclofenac, estrone (E1) and 17α-ethinylestradiol (EE2) were studied in large laboratory-scale wastewater treatment plants (WWTPs) with high nitrifying activity. Activated sludge (AS) with sludge retention times (SRTs) of 12days and 14days in sequencing batch reactors (SBRs) and 30days, 60days and 90days in membrane bioreactors (MBRs) were examined at 8°C and 12°C. Concentrations of pharmaceuticals and their main metabolites were analysed in liquid phase and solid phase of AS by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A remarkable amount of contaminants were detected in solids of AS, meaning the accumulation of micropollutants in bacterial cells. The biodegradation rate constants (Kbiol) were affected by SRT and temperature. MBR with a 90-day SRT showed the best results of removal. Conventional SBR process was inefficient at 8°C showing Kbiol values lower than 0.5lgSS(-1)d(-1) for studied micropollutants. PMID:27128192

  8. Effects of hydraulic retention time and carbon to nitrogen ratio on micro-pollutant biodegradation in membrane bioreactor for leachate treatment.

    Science.gov (United States)

    Boonnorat, Jarungwit; Techkarnjanaruk, Somkiet; Honda, Ryo; Prachanurak, Pradthana

    2016-11-01

    This research investigated the biodegradation of the micro-pollutants in leachate by the membrane bioreactor (MBR) system under six treatment conditions, comprising two C/N ratios (6, 10) and three hydraulic retention time (HRT) durations (6, 12, 24h). The experimental results indicated that the C/N 6 environment was more advantageous to the bacterial growth. The bacterial communities residing in the sludge were those of heterotrophic bacteria (HB), heterotrophic nitrifying bacteria (HNB) and ammonia oxidizing bacteria (AOB). It was found that HB and HNB produced phenol hydroxylase (PH), esterase (EST), phthalate dioxygenase (PDO) and laccase (LAC) and also enhanced the biodegradation rate constants (k) in the system. At the same time, AOB promoted the production of HB and HNB. The findings also revealed that the 12h HRT was the optimal condition with regard to the highest growth of the bacteria responsible for the biodegradation of phenols and phthalates. Meanwhile, the longer HRT duration (i.e. 24h) was required to effectively bio-degrade carbamazepine (CBZ), N,N-diethyl-m-toluamide (DEET) and diclofenac (DCF). PMID:27475331

  9. Shifts in the microbial community, nitrifiers and denitrifiers in the biofilm in a full-scale rotating biological contactor.

    Science.gov (United States)

    Peng, Xingxing; Guo, Feng; Ju, Feng; Zhang, Tong

    2014-07-15

    The objective of this study was to investigate the microbial community shifts, especially nitrifiers and denitrifiers, in the biofilm of two rotating biological contactor (RBC) trains with different running times along the plug flowpath. The microbial consortia were profiled using multiple approaches, including 454 high-throughput sequencing of the V3-V4 region of 16S rRNA gene, clone libraries, and quantitative polymerase chain reaction (qPCR). The results demonstrated that (1) the overall microbial community at different locations had distinct patterns, that is, there were similar microbial communities at the beginnings of the two RBC trains and completely different populations at the ends of the two RBC trains; (2) nitrifiers, including ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB, Nitrosomonas) and nitrite-oxidizing bacteria (NOB, Nitrospira), increased in relative abundance in the biofilm along the flowpath, whereas denitrifiers (Rhodanobacter, Paracoccus, Thauera, and Azoarcus) markedly decreased; (3) the AOA were subdominant to the AOB in all sampled sections; and (4) strong ecological associations were shown among different bacteria. Overall, the results of this study provided more comprehensive information regarding the biofilm community composition and assemblies in full-scale RBCs.

  10. Carrier effects on tertiary nitrifying moving bed biofilm reactor: An examination of performance, biofilm and biologically produced solids.

    Science.gov (United States)

    Forrest, Daina; Delatolla, Robert; Kennedy, Kevin

    2016-01-01

    Increasingly stricter ammonia and nitrogen release regulations with respect to wastewater effluents are creating a need for tertiary treatment systems. The moving bed biofilm reactor (MBBR) is being considered as an upgrade option for an increasing number of wastewater treatment facilities due to its small footprint and ease of operation. Despite the MBBRs creation as a system to remove nitrogen, recent research on MBBR systems showing that the system's performance is directly related to carrier surface area and is irrespective of carrier shape and type has been performed exclusively on chemical oxygen demand (COD) removal systems. Furthermore, the influence of carrier type on the solids produced by MBBR systems has also been exclusively studied for COD removal systems. This work investigates the effects of three specific carrier types on ammonia removal rates, biofilm morphology, along with solids production and settleability of tertiary nitrifying MBBR systems. The study concludes that carrier type has no significant effect on tertiary nitrifying MBBR system performance under steady, moderate loading conditions. The research does however highlight the propensity of greater surface area to volume carriers to become clogged under high loading conditions and that the high surface area carriers investigated in this study required longer adjustment periods to changes in loading after becoming clogged.

  11. High Oxygen Concentration Increases the Abundance and Activity of Bacterial Rather than Archaeal Nitrifiers in Rice Field Soil.

    Science.gov (United States)

    Ke, Xiubin; Lu, Wei; Conrad, Ralf

    2015-11-01

    Oxygen is considered as a limiting factor for nitrification in rice paddy soil. However, little is known about how the nitrifying microbial community responds to different oxygen concentrations at community and transcript level. In this study, soil and roots were harvested from 50-day-old rice microcosms and were incubated for up to 45 days under two oxygen concentrations: 2 % O(2) and 20 % O(2) (ambient air). Nitrification rates were measured from the accumulation of nitrite plus nitrate. The population dynamics of bacterial (AOB) and archaeal (AOA) ammonia oxidizers was determined from the abundance (using quantitative PCR (qPCR)) and composition (using terminal restriction fragment length polymorphism and cloning/sequencing) of their amoA genes, that of nitrite oxidizers (NOB) by quantifying the nxrA gene of Nitrobacter spp. and the 16S rRNA gene of Nitrospira spp. The activity of the nitrifiers was determined by quantifying the copy numbers of amoA and nxrA transcripts (using RT-qPCR). Different oxygen concentrations did not affect the community compositions of AOB, AOA, and NOB, which however were different between surface soil, bottom soil, and rice roots. However, nitrification rates were higher under ambient air than 2 % O(2), and abundance and transcript activities of AOB, but not of AOA, were also higher. Abundance and transcript copy numbers of Nitrobacter were also higher at ambient air. These results indicate that AOB and NOB, but not AOA, were sensitive to oxygen availability. PMID:26054702

  12. Management of Microbial Communities through Transient Disturbances Enhances the Functional Resilience of Nitrifying Gas-Biofilters to Future Disturbances.

    Science.gov (United States)

    Cabrol, Léa; Poly, Franck; Malhautier, Luc; Pommier, Thomas; Lerondelle, Catherine; Verstraete, Willy; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis; Le Roux, Xavier

    2016-01-01

    Microbial communities have a key role for the performance of engineered ecosystems such as waste gas biofilters. Maintaining constant performance despite fluctuating environmental conditions is of prime interest, but it is highly challenging because the mechanisms that drive the response of microbial communities to disturbances still have to be disentangled. Here we demonstrate that the bioprocess performance and stability can be improved and reinforced in the face of disturbances, through a rationally predefined strategy of microbial resource management (MRM). This strategy was experimentally validated in replicated pilot-scale nitrifying gas-biofilters, for the two steps of nitrification. The associated biological mechanisms were unraveled through analysis of functions, abundances and community compositions for the major actors of nitrification in these biofilters, that is, ammonia-oxidizing bacteria (AOB) and Nitrobacter-like nitrite-oxidizers (NOB). Our MRM strategy, based on the application of successive, transient perturbations of increasing intensity, enabled to steer the nitrifier community in a favorable way through the selection of more resistant AOB and NOB sharing functional gene sequences close to those of, respectively, Nitrosomonas eutropha and Nitrobacter hamburgensis that are well adapted to high N load. The induced community shifts resulted in significant enhancement of nitrification resilience capacity following the intense perturbation. PMID:26651080

  13. The effects of salinity on nitrification using halophilic nitrifiers in a Sequencing Batch Reactor treating hypersaline wastewater.

    Science.gov (United States)

    Cui, You-Wei; Zhang, Hong-Yu; Ding, Jie-Ran; Peng, Yong-Zhen

    2016-01-01

    With annual increases in the generation and use of saline wastewater, the need to avoid environmental problems such as eutrophication is critical. A previous study identified ways to start up a halophilic sludge domesticated from estuarine sediments to remove nitrogen from wastewater with a salinity of 30 g/L. This investigation expands that work to explore the impact of salinity on nitrogen removal. This study demonstrated that the mixed halophilic consortia removed nitrogen from wastewater with a salinity of 30-85 g/L. A kinetic analysis showed that halophilic nitrifiers selected based on hypersalinity were characterized by low Ks, μmax and specific ammonium oxidization rates. This explains the decrease in ammonium removal efficiency in the high salinity operational phases. Salinity inhibited ammonia oxidizing bacteria (AOB) activity, as well as the number of dominant AOB, but did not significantly affect the AOB dominant species. Three most dominant AOB lineages in the halophilic sludge were Nitrosomonas marina, Nitrosomonas europaea, and Nitrosococcus mobilis. Nitrosomonas europaea and Nitrosococcus mobilis were mainly affected by salinity, while nitrite accumulation and ammonia loading played the key role in determining the abundance of Nitrosococcus mobilis and Nitrosococcus europaea. The study contributes insights about shifts in halophilic nitrifying bacterial populations. PMID:27109617

  14. Emergent macrophytes select for nitrifying and denitrifying microorganisms in constructed wetlands

    Science.gov (United States)

    Trias, Rosalia; Ramió Pujol, Sara; Bañeras, Lluis

    2014-05-01

    The use of constructed wetlands for wastewater treatment is a reliable low-cost alternative that has been widely developed during the last years. Several processes involving plants, sediments, and microbial communities contribute to nitrogen removal in wetlands. Vegetation plays an important role in this process, not only by nutrient assimilation but also by the stimulation of the plant associated microbiota. Plants supply oxygen at the close proximity of the root surface that may favour ammonia oxidizers. At the same time, exudation of organic compounds potentially speeds-up denitrification in the anoxic environment. The aim of this work was to understand the plant-microbe interactions at the root level in the Empuriabrava free water surface constructed wetland (Spain). The roots of the macrophytes Typha latifolia, Typha angustifolia, Phragmites australis and Bolboschoenus maritimus were sampled at four dates from January to September 2012, covering all the stages of plant growth. Additionally, sediment surrounding vegetation and non-vegetated sediments were sampled. Microbial community structure was analysed by pyrosequencing of bacterial and archaeal 16S rDNA and functional genes (nirK, nirS, nosZ and amoA). Bacterial communities were significantly different in sediments of the vegetated areas compared to the root surface. Plant roots exhibited a higher proportion of proteobacteria whereas Actinobacteria were dominant in sediments. The nitrifiers Nitrosomonas sp. and Nitrosococcus sp. accounted for less than 1% of all sequences. Archaeal communities were dominated by the Miscellaneous Crenarchaeotic Groups C2 and C3 and Methanomicrobia. Higher relative abundances of MCG were found in roots of P. australis, B. maritimus and T. angustifolia. Ammonia oxidizing archaea accounted for less than 0.1% of all sequences but were consistently more abundant in sediment samples compared to roots. NirK and NirS-type bacterial communities showed clearly distinct distribution

  15. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Scott D [Mississippi State Univ., Mississippi State, MS (United States)

    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.

  17. Cropping systems modulate the rate and magnitude of soil microbial autotrophic CO2 fixation in soil

    Directory of Open Access Journals (Sweden)

    Xiao Hong Wu

    2015-05-01

    Full Text Available The effect of different cropping systems on CO2 fixation by soil microorganisms was studied by comparing soils from three exemplary cropping systems: continuous cropping of paddy rice (rice-rice, rotation of paddy rice and rapeseed (rice-rapeseed, and rotated cropping of rapeseed and corn (rapeseed-corn. Soils from different cropping systems were continuously labeling with 14C-CO2 for 110 days. The CO2-fixing bacterial communities were investigated by analyzing the cbbL gene encoding ribulose-1,5-bisphosphate carboxylase oxygenase (RubisCO. Abundance, diversity and activity of cbbL-carrying bacteria were analyzed by quantitative PCR, cbbL clone libraries and enzyme assays. After 110 days incubation, substantial amounts of 14C-CO2 were incorporated into soil organic carbon (14C-SOC and microbial organic carbon (14C-MBC. Rice-rice rotated soil showed stronger incorporation rates when looking at 14C-SOC and 14C-MBC contents. These differences in incorporation rates were also reflected by RubisCO activities. 14C-MBC, cbbL gene abundances and RubisCO activity were found to correlate significantly with 14C-SOC, indicating cbbL-carrying bacteria to be key players for CO2 fixation in these soils. The analysis of clone libraries revealed distinct cbbL-carrying bacterial communities for the individual soils analyzed. Most of the identified operational taxonomic units (OTU were related to Nitrobacter hamburgensis, Methylibium petroleiphilum, Rhodoblastus acidophilus, Bradyrhizobium, Cupriavidus metallidurans, Rubrivivax, Burkholderia, stappia and Thiobacillus thiophilus. OTUs related to Rubrivivax gelatinosus were specific for rice-rice soil. OTUs linked to Methylibium petroleiphilum were exclusively found in rice-rapeseed soil. Observed differences could be linked to differences in soil parameters such as SOC. We conclude that the long-term application of cropping systems alters underlying soil parameters, which in turn selects for distinct autotrophic

  18. 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.

  19. Nitrification in trickling filters applied to the post-treatment of effluents from UASB reactor: correlation between ammonia removal and the relative abundance of nitrifying bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Missagia, B. S.; Almeida, P. G. S. de; Silva, S. Q.; Chernicharo, C. A. L.

    2009-07-01

    The number and physiological activity of nitrifying bacteria in wastewater treatment reactors are considered the ratelimiting parameters for the bioconversion of nitrogen in sewage. Since the presence of ammonia and nitrite oxidizers can be correlated with their activity. In situ probe counts can be correlated with the nitrification rates in order to compare the efficiency of different media types. (Author)

  20. Anaerobic membrane bio-reactors for severe industrial effluents and urban spill waters: The AMBROSIUS project

    NARCIS (Netherlands)

    Van Lier, J.B.; Ozgun, H.; Ersahin, M.E.; Dereli, R.K.

    2013-01-01

    With growing application experiences from aerobic membrane bioreactors, combination of membrane and anaerobic processes become more and more attractive and feasible. In anaerobic membrane bioreactors (AnMBRs), biomass and particulate organic matter are physically retained inside the reactor, providi

  1. Modular bioreactor for the remediation of liquid streams and methods for using the same

    Science.gov (United States)

    Noah, Karl S.; Sayer, Raymond L.; Thompson, David N.

    1998-01-01

    The present invention is directed to a bioreactor system for the remediation of contaminated liquid streams. The bioreactor system is composed of at least one and often a series of sub-units referred to as bioreactor modules. The modular nature of the system allows bioreactor systems be subdivided into smaller units and transported to waste sites where they are combined to form bioreactor systems of any size. The bioreactor modules further comprises reactor fill materials in the bioreactor module that remove the contaminants from the contaminated stream. To ensure that the stream thoroughly contacts the reactor fill materials, each bioreactor module comprises means for directing the flow of the stream in a vertical direction and means for directing the flow of the stream in a horizontal direction. In a preferred embodiment, the reactor fill comprises a sulfate reducing bacteria which is particularly useful for precipitating metals from acid mine streams.

  2. 冰冻对硝化细菌制剂活性的影响%Effects of frost on the activity of nitrifying bacteria preparation

    Institute of Scientific and Technical Information of China (English)

    任杰; 周洋; 孔小蓉; 宋志文

    2014-01-01

    在实验室模拟条件下,研究冰冻对淡水型硝化细菌和海水型硝化细菌制剂中氨氧化细菌和亚硝酸盐氧化细菌活性的影响。结果表明,冰冻对淡水型硝化细菌和海水型硝化细菌制剂活性均有较为明显的抑制作用,且10 d处理组的抑制作用高于5 d处理组,对淡水型硝化细菌制剂活性的抑制作用大于海水型硝化细菌制剂。液体硝化细菌制剂在冬季运输和保存过程中要采取保温措施,以避免由于冰冻导致的菌剂活性降低。%Simulated conditions in the laboratory to study frost effects on activity of ammonia -oxidi-zing bacteria and nitrite -oxidizing bacteria in freshwater and marine nitrifying bacteria preparation . The results showed that frost had obvious inhibitory effect on activity of freshwater and marine nitrif-ying bacteria preparation .And the inhibitory effect on frost for ten days was greater than on frost for five days ,the inhibitory effect on activity of nitrifying bacteria preparation was greater than on marine nitrifying bacteria preparation .In order to avoid the decrease of bacteria preparation activity because of frost ,insulation measures should be taken to liquid nitrifying bacteria preparation during the transport and storage in winter .

  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)

    Jessica K Cole

    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. Operation of a fluidized-bed bioreactor for denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hancher, C W; Taylor, P A; Napier, J M

    1978-01-01

    Two denitrification fluidized-bed bioreactors of the same length (i.e., 5 m) but with different inside diameters (i.e., 5 and 10 cm) have been operated on feed ranging in nitrate concentration from 200 to 2000 g/m/sup 3/; thus far, good agreement has been obtained. Two 10-cm-ID bioreactors operating in series have also been tested; the results are in accordance with predicted results based on the performance of a 5-cm-ID bioreactor. The overall denitrification rate in the dual 10-cm-ID bioreactor system was found to be 23 kg N(NO/sub 3//sup -/)/day-m/sup 3/ using feed with a nitrate concentration of 1800 g/m/sup 3/. Data obtained in operating-temperature tests indicate that the maximum denitrification rate is achieved between 22 and 30/sup 0/C. These data will form the basis of the design of our mobile pilot plant which consists of dual 20-cm-ID by 7.3-m-long bioreactors.

  6. Operation of a fluidized-bed bioreactor for denitrification

    International Nuclear Information System (INIS)

    Two denitrification fluidized-bed bioreactors of the same length (i.e., 5 m) but with different inside diameters (i.e., 5 and 10 cm) have been operated on feed ranging in nitrate concentration from 200 to 2000 g/m3; thus far, good agreement has been obtained. Two 10-cm-ID bioreactors operating in series have also been tested; the results are in accordance with predicted results based on the performance of a 5-cm-ID bioreactor. The overall denitrification rate in the dual 10-cm-ID bioreactor system was found to be 23 kg N(NO3-)/day-m3 using feed with a nitrate concentration of 1800 g/m3. Data obtained in operating-temperature tests indicate that the maximum denitrification rate is achieved between 22 and 300C. These data will form the basis of the design of our mobile pilot plant which consists of dual 20-cm-ID by 7.3-m-long bioreactors

  7. Bioreactor for acid mine drainage control

    Science.gov (United States)

    Zaluski, Marek H.; Manchester, Kenneth R.

    2001-01-01

    A bioreactor for reacting an aqueous heavy metal and sulfate containing mine drainage solution with sulfate reducing bacteria to produce heavy metal sulfides and reduce the sulfuric acid content of the solution. The reactor is an elongated, horizontal trough defining an inlet section and a reaction section. An inlet manifold adjacent the inlet section distributes aqueous mine drainage solution into the inlet section for flow through the inlet section and reaction section. A sulfate reducing bacteria and bacteria nutrient composition in the inlet section provides sulfate reducing bacteria that with the sulfuric acid and heavy metals in the solution to form solid metal sulfides. The sulfate reducing bacteria and bacteria nutrient composition is retained in the cells of a honeycomb structure formed of cellular honeycomb panels mounted in the reactor inlet section. The honeycomb panels extend upwardly in the inlet section at an acute angle with respect to the horizontal. The cells defined in each panel are thereby offset with respect to the honeycomb cells in each adjacent panel in order to define a tortuous path for the flow of the aqueous solution.

  8. Hydrodynamics of an Electrochemical Membrane Bioreactor

    Science.gov (United States)

    Wang, Ya-Zhou; Wang, Yun-Kun; He, Chuan-Shu; Yang, Hou-Yun; Sheng, Guo-Ping; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2015-05-01

    An electrochemical membrane bioreactor (EMBR) has recently been developed for energy recovery and wastewater treatment. The hydrodynamics of the EMBR would significantly affect the mass transfers and reaction kinetics, exerting a pronounced effect on reactor performance. However, only scarce information is available to date. In this study, the hydrodynamic characteristics of the EMBR were investigated through various approaches. Tracer tests were adopted to generate residence time distribution curves at various hydraulic residence times, and three hydraulic models were developed to simulate the results of tracer studies. In addition, the detailed flow patterns of the EMBR were acquired from a computational fluid dynamics (CFD) simulation. Compared to the tank-in-series and axial dispersion ones, the Martin model could describe hydraulic performance of the EBMR better. CFD simulation results clearly indicated the existence of a preferential or circuitous flow in the EMBR. Moreover, the possible locations of dead zones in the EMBR were visualized through the CFD simulation. Based on these results, the relationship between the reactor performance and the hydrodynamics of EMBR was further elucidated relative to the current generation. The results of this study would benefit the design, operation and optimization of the EMBR for simultaneous energy recovery and wastewater treatment.

  9. Osteocytes Mechanosensing in NASA Rotating Wall Bioreactor

    Science.gov (United States)

    Spatz, Jordan; Sibonga, Jean; Wu, Honglu; Barry, Kevin; Bouxsein, Mary; Pajevic, Paola Divieti

    2010-01-01

    Osteocyte cells are the most abundant (90%) yet least understood bone cell type in the human body. Osteocytes are theorized to be the mechanosensors and transducers of mechanical load for bones, yet the biological mechanism of this action remains elusive. However, recent discoveries in osteocyte cell biology have shed light on their importance as key mechanosensing cells regulating bone remodeling and phosphate homeostasis. The aim of this project was to characterize gene expression patterns and protein levels following exposure of MLO-Y4, a very well characterized murine osteocyte-like cell line, to simulated microgravity using the NASA Rotating Wall Vessel (RWV) Bioreactor. To determine mechanistic pathways of the osteocyte's gravity sensing ability, we evaluated in vitro gene and protein expression of osteocytes exposed to simulated microgravity. Improved understanding of the fundamental mechanisms of mechano transduction at the osteocyte cellular level may lead to revolutionary treatment otions to mitigate the effects of bone loss encountered by astronauts on long duration space missions and provide tailored treatment options for maintaining bone strength of immobilized/partially paralyzed patients here on Earth.

  10. Proteins causing membrane fouling in membrane bioreactors.

    Science.gov (United States)

    Miyoshi, Taro; Nagai, Yuhei; Aizawa, Tomoyasu; Kimura, Katsuki; Watanabe, Yoshimasa

    2015-01-01

    In this study, the details of proteins causing membrane fouling in membrane bioreactors (MBRs) treating real municipal wastewater were investigated. Two separate pilot-scale MBRs were continuously operated under significantly different operating conditions; one MBR was a submerged type whereas the other was a side-stream type. The submerged and side-stream MBRs were operated for 20 and 10 days, respectively. At the end of continuous operation, the foulants were extracted from the fouled membranes. The proteins contained in the extracted foulants were enriched by using the combination of crude concentration with an ultrafiltration membrane and trichloroacetic acid precipitation, and then separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The N-terminal amino acid sequencing analysis of the proteins which formed intensive spots on the 2D-PAGE gels allowed us to partially identify one protein (OmpA family protein originated from genus Brevundimonas or Riemerella anatipestifer) from the foulant obtained from the submerged MBR, and two proteins (OprD and OprF originated from genus Pseudomonas) from that obtained from the side-stream MBR. Despite the significant difference in operating conditions of the two MBRs, all proteins identified in this study belong to β-barrel protein. These findings strongly suggest the importance of β-barrel proteins in developing membrane fouling in MBRs.

  11. Performance of anaerobic membrane bioreactor during digestion and thickening of aerobic membrane bioreactor excess sludge.

    Science.gov (United States)

    Hafuka, Akira; Mimura, Kazuhisa; Ding, Qing; Yamamura, Hiroshi; Satoh, Hisashi; Watanabe, Yoshimasa

    2016-10-01

    In this study, we evaluated the performance of an anaerobic membrane bioreactor in terms of digestion and thickening of excess sludge from an aerobic membrane bioreactor. A digestion reactor equipped with an external polytetrafluoroethylene tubular microfiltration membrane module was operated in semi-batch mode. Solids were concentrated by repeated membrane filtration and sludge feeding, and their concentration reached 25,400mg/L after 92d. A high chemical oxygen demand (COD) removal efficiency, i.e., 98%, was achieved during operation. A hydraulic retention time of 34d and a pulse organic loading rate of 2200mg-COD/(L-reactor) gave a biogas production rate and biogas yield of 1.33L/(reactor d) and 0.08L/g-CODinput, respectively. The external membrane unit worked well without membrane cleaning for 90d. The transmembrane pressure reached 25kPa and the filtration flux decreased by 80% because of membrane fouling after operation for 90d. PMID:27394993

  12. Forest annual carbon cost: a global-scale analysis of autotrophic respiration.

    Science.gov (United States)

    Piao, Shilong; Luyssaert, Sebastiaan; Ciais, Philippe; Janssens, Ivan A; Chen, Anping; Cao, Chao; Fang, Jingyun; Friedlingstein, Pierre; Luo, Yiqi; Wang, Shaopeng

    2010-03-01

    Forest autotrophic respiration (R(a)) plays an important role in the carbon balance of forest ecosystems. However, its drivers at the global scale are not well known. Based on a global forest database, we explore the relationships of annual R(a) with mean annual temperature (MAT) and biotic factors including net primary productivity (NPP), total biomass, stand age, mean tree height, and maximum leaf area index (LAI). The results show that the spatial patterns of forest annual R(a) at the global scale are largely controlled by temperature. R(a) is composed of growth (R(g)) and maintenance respiration (R(m)). We used a modified Arrhenius equation to express the relationship between R(a) and MAT. This relationship was calibrated with our data and shows that a 10 degrees C increase in MAT will result in an increase of annual R(m) by a factor of 1.9-2.5 (Q10). We also found that the fraction of total assimilation (gross primary production, GPP) used in R(a) is lowest in the temperate regions characterized by a MAT of approximately 11 degrees C. Although we could not confirm a relationship between the ratio of R(a) to GPP and age across all forest sites, the R(a) to GPP ratio tends to significantly increase in response to increasing age for sites with MAT between 8 degrees and 12 degrees C. At the plant scale, direct up-scaled R(a) estimates were found to increase as a power function with forest total biomass; however, the coefficient of the power function (0.2) was much smaller than that expected from previous studies (0.75 or 1). At the ecosystem scale, R(a) estimates based on both GPP - NPP and TER - R(h) (total ecosystem respiration - heterotrophic respiration) were not significantly correlated with forest total biomass (P > 0.05) with either a linear or a power function, implying that the previous individual-based metabolic theory may be not suitable for the application at ecosystem scale. PMID:20426325

  13. A new dynamic model for highly efficient mass transfer in aerated bioreactors and consequences for kLa identification.

    Science.gov (United States)

    Müller, Stefan; Murray, Douglas B; Machne, Rainer

    2012-12-01

    Gas-liquid mass transfer is often rate-limiting in laboratory and industrial cultures of aerobic or autotrophic organisms. The volumetric mass transfer coefficient k(L) a is a crucial characteristic for comparing, optimizing, and upscaling mass transfer efficiency of bioreactors. Reliable dynamic models and resulting methods for parameter identification are needed for quantitative modeling of microbial growth dynamics. We describe a laboratory-scale stirred tank reactor (STR) with a highly efficient aeration system (k(L) a ≈ 570 h(-1)). The reactor can sustain yeast culture with high cell density and high oxygen uptake rate, leading to a significant drop in gas concentration from inflow to outflow (by 21%). Standard models fail to predict the observed mass transfer dynamics and to identify k(L) a correctly. In order to capture the concentration gradient in the gas phase, we refine a standard ordinary differential equation (ODE) model and obtain a system of partial integro-differential equations (PIDE), for which we derive an approximate analytical solution. Specific reactor configurations, in particular a relatively short bubble residence time, allow a quasi steady-state approximation of the PIDE system by a simpler ODE model which still accounts for the concentration gradient. Moreover, we perform an appropriate scaling of all variables and parameters. In particular, we introduce the dimensionless overall efficiency κ, which is more informative than k(L) a since it combines the effects of gas inflow, exchange, and solution. Current standard models of mass transfer in laboratory-scale aerated STRs neglect the gradient in the gas concentration, which arises from highly efficient bubbling systems and high cellular exchange rates. The resulting error in the identification of κ (and hence k(L) a) increases dramatically with increasing mass transfer efficiency. Notably, the error differs between cell-free and culture-based methods of parameter identification

  14. A shift in the archaeal nitrifier community in response to natural and anthropogenic disturbances in the northern Gulf of Mexico.

    Science.gov (United States)

    Newell, Silvia E; Eveillard, Damien; McCarthy, Mark J; Gardner, Wayne S; Liu, Zhanfei; Ward, Bess B

    2014-02-01

    The Gulf of Mexico is affected by hurricanes and suffers seasonal hypoxia. The Deepwater Horizon oil spill impacted every trophic level in the coastal region. Despite their importance in bioremediation and biogeochemical cycles, it is difficult to predict the responses of microbial communities to physical and anthropogenic disturbances. Here, we quantify sediment ammonia-oxidizing archaeal (AOA) community diversity, resistance and resilience, and important geochemical factors after major hurricanes and the oil spill. Dominant AOA archetypes correlated with different geochemical factors, suggesting that different AOA are constrained by distinct parameters. Diversity was lowest after the hurricanes, showing weak resistance to physical disturbances. However, diversity was highest during the oil spill and coincided with a community shift, suggesting a new alternative stable state sustained for at least 1 year. The new AOA community was not significantly different from that at the spill site 1 year after the spill. This sustained shift in nitrifier community structure may be a result of oil exposure. PMID:24596268

  15. Biodegradation of ibuprofen, diclofenac and carbamazepine in nitrifying activated sludge under 12 °C temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kruglova, Antonina; Ahlgren, Pia; Korhonen, Nasti; Rantanen, Pirjo; Mikola, Anna; Vahala, Riku

    2014-11-15

    Pharmaceuticals constitute a well-known group of emerging contaminants with an increasing significance in water pollution. This study focuses on three pharmaceuticals extensively used in Finland and which can be found in environmental waters: ibuprofen, diclofenac and carbamazepine. Biodegradation experiments were conducted in a full-scale Wastewater Treatment Plant (WWTP) and in laboratory-scale Sequencing Batch Reactors (SBRs). The SBRs were operated at 12 °C, with a sludge retention time (SRT) 10–12 d and organic loading rates (OLRs) of 0.17, 0.27 and 0.33 kg BOD{sub 7} m{sup -3}d{sup -1}. Ibuprofen was found to biodegrade up to 99%. The biodegradation rate constants (k{sub biol}) for ibuprofen were calculated for full-scale and laboratory processes as well as under different laboratory conditions and found to differ from 0.9 up to 5.0 l g{sub SS}{sup −1} d{sup −1}. Diclofenac demonstrated an unexpected immediate drop of concentration in three SBRs and partial recovery of the initial concentration in one of the reactors. High fluctuating in diclofenac concentration was presumably caused by removal of this compound under different concentrations of nitrites during development of nitrifying activated sludge. Carbamazepine showed no biodegradation in all the experiments. - Highlights: • The biodegradation of three pharmaceuticals examined under 12 °C conditions. • k{sub biol} constants for ibuprofen proposed for full-scale and laboratory-scale processes. • Influence of OLR on ibuprofen biodegradation was studied. • Removal followed by recovery of diclofenac detected in nitrifying activated sludge.

  16. Biodegradation of ibuprofen, diclofenac and carbamazepine in nitrifying activated sludge under 12 °C temperature conditions

    International Nuclear Information System (INIS)

    Pharmaceuticals constitute a well-known group of emerging contaminants with an increasing significance in water pollution. This study focuses on three pharmaceuticals extensively used in Finland and which can be found in environmental waters: ibuprofen, diclofenac and carbamazepine. Biodegradation experiments were conducted in a full-scale Wastewater Treatment Plant (WWTP) and in laboratory-scale Sequencing Batch Reactors (SBRs). The SBRs were operated at 12 °C, with a sludge retention time (SRT) 10–12 d and organic loading rates (OLRs) of 0.17, 0.27 and 0.33 kg BOD7 m-3d-1. Ibuprofen was found to biodegrade up to 99%. The biodegradation rate constants (kbiol) for ibuprofen were calculated for full-scale and laboratory processes as well as under different laboratory conditions and found to differ from 0.9 up to 5.0 l gSS−1 d−1. Diclofenac demonstrated an unexpected immediate drop of concentration in three SBRs and partial recovery of the initial concentration in one of the reactors. High fluctuating in diclofenac concentration was presumably caused by removal of this compound under different concentrations of nitrites during development of nitrifying activated sludge. Carbamazepine showed no biodegradation in all the experiments. - Highlights: • The biodegradation of three pharmaceuticals examined under 12 °C conditions. • kbiol constants for ibuprofen proposed for full-scale and laboratory-scale processes. • Influence of OLR on ibuprofen biodegradation was studied. • Removal followed by recovery of diclofenac detected in nitrifying activated sludge

  17. Real-time PCR assay for the simultaneous quantification of nitrifying and denitrifying bacteria in activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Geets, J.; Cooman, M. de; Wittebolle, L.; Verstraete, W.; Boon, N. [Ghent Univ. (BE). Lab. of Microbial Ecology and Technology (LabMET); Heylen, K.; Vanparys, B.; Vos, P. de [Ghent Univ. (Belgium). Dept. of Biochemistry, Physiology and Microbiology

    2007-05-15

    In order to improve wastewater treatment processes, a need exists for tools that rapidly give detailed insight into the community structure of activated sludge, supplementary to chemical and physical data. In this study, the advantages of microarrays and quantitative polymerase chin reaction (PCR) methods were combined into a real-time PCR assay that allows the simultaneous quantification of phylogenetic and functional genes involved in nitrification and denitrification processes. Simultaneous quantification was possible along a 5-log dynamic range and with high linear correlation (R{sup 2}>0.98). The specificity of the assay was confirmed by cloning and sequencing analyses of PCR amplicons obtained from activated sludge. The real-time assay was validated on mixed liquid samples of different treatment plants, which varied in nitrogen removal rate. The abundance of ammonia oxidizers was in the order of magnitude of 10{sup 6} down to 10{sup 4} ml{sup -1}, whereas nitrite oxidizers were less abundant (10{sup 3}-10{sup 1} order of magnitude). The results were in correspondence with the nitrite oxidation rate in the sludge types. As for the nirS, nirK, and nosZ gene copy numbers, their abundance was generally in the order of magnitude of 10{sup 8}-10{sup 5}. When sludge samples were subjected to lab-scale perturbations, a decrease in nitrification rate was reflected within 18 h in the copy numbers of nitrifier genes (decrease with 1 to 5 log units), whereas denitrification genes remained rather unaffected. These results demonstrate that the method is a fast and accurate tool for the analysis of the (de)nitrifying community structure and size in both natural and engineered environmental samples. (orig.)

  18. Reducing N2O Emission from a Domestic-Strength Nitrifying Culture by Free Nitrous Acid-Based Sludge Treatment.

    Science.gov (United States)

    Wang, Dongbo; Wang, Qilin; Laloo, Andrew Elohim; Yuan, Zhiguo

    2016-07-19

    An increase of nitrite in the domestic-strength range is generally recognized to stimulate nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). It was found in this study, however, that N2O emission from a mainstream nitritation system (cyclic nitrite = 25-45 mg of N/L) that was established by free nitrous acid (FNA)-based sludge treatment was not higher but much lower than that from the initial nitrifying system with full conversion of NH4(+)-N to NO3(-)-N. Under dissolved oxygen (DO) levels of 2.5-3.0 mg/L, N2O emission from the nitritation stage was 76% lower than that from the initial stage. Even when the DO level was reduced to 0.3-0.8 mg/L, N2O emission from the nitritation stage was still 40% lower. An investigation of the mechanism showed that FNA treatment caused a shift of the stimulation threshold of nitrite on N2O emission. At the nitritation stage, the maximal N2O emission factor occurred at ∼16 mg of N/(L of nitrite). However, it increased with increasing nitrite in the range of 0-56 mg of N/L at the initial stage. FNA treatment decreased the biomass-specific N2O production rate, suggesting that the enzymes relevant to nitrifier denitrification were inhibited. Microbial analysis revealed that FNA treatment decreased the microbial community diversity but increased the abundances of AOB and denitrifiers. PMID:27294698

  19. Development of a Laminar Flow Bioreactor by Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Meir Israelowitz

    2012-01-01

    Full Text Available The purpose of this study is to improve the design of a bioreactor for growing bone and other three-dimensional tissues using a computational fluid dynamics (CFD software to simulate flow through a porous scaffold, and to recommend design changes based on the results. Basic requirements for CFD modeling were that the flow in the reactor should be laminar and any flow stagnation should be avoided in order to support cellular growth within the scaffold. We simulated three different designs with different permeability values of the scaffold and tissue. Model simulation addressed flow patterns in combination with pressure distribution within the bioreactor. Pressure build-up and turbulent flow within the reactor was solved by introduction of an integrated bypass system for pressure release. The use of CFD afforded direct feedback to optimize the bioreactor design.

  20. Enhancing inhibited fermentations through a dynamic electro-membrane bioreactor

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Garde, Arvid; Rype, Jens-Ulrik;

    its strong potential for increasing productivity and product yield has been verified. REED uses ion exchange membranes and electrical potential gradients to selectively separate the target ion. The main limitation of using membrane separation combined with bioreactors is membrane fouling. REED...... technology ensures long operation time by reversing periodically the polarity of the imposed electrical field to significantly reduce the influence of membrane fouling. The periodic nature of the electrically driven membrane separation process makes the membrane bioreactor operation non trivial....... This challenging operation is associated with different dynamic behaviors of the individual units plus their interaction. The purpose of this contribution is to show the results of experimental and model based efforts done in order to investigate the operation of a membrane bioreactor. From modeling point of view...

  1. Bioreactor droplets from liposome-stabilized all-aqueous emulsions

    Science.gov (United States)

    Dewey, Daniel C.; Strulson, Christopher A.; Cacace, David N.; Bevilacqua, Philip C.; Keating, Christine D.

    2014-08-01

    Artificial bioreactors are desirable for in vitro biochemical studies and as protocells. A key challenge is maintaining a favourable internal environment while allowing substrate entry and product departure. We show that semipermeable, size-controlled bioreactors with aqueous, macromolecularly crowded interiors can be assembled by liposome stabilization of an all-aqueous emulsion. Dextran-rich aqueous droplets are dispersed in a continuous polyethylene glycol (PEG)-rich aqueous phase, with coalescence inhibited by adsorbed ~130-nm diameter liposomes. Fluorescence recovery after photobleaching and dynamic light scattering data indicate that the liposomes, which are PEGylated and negatively charged, remain intact at the interface for extended time. Inter-droplet repulsion provides electrostatic stabilization of the emulsion, with droplet coalescence prevented even for submonolayer interfacial coatings. RNA and DNA can enter and exit aqueous droplets by diffusion, with final concentrations dictated by partitioning. The capacity to serve as microscale bioreactors is established by demonstrating a ribozyme cleavage reaction within the liposome-coated droplets.

  2. Miniature Bioreactor System for Long-Term Cell Culture

    Science.gov (United States)

    Gonda, Steve R.; Kleis, Stanley J.; Geffert, Sandara K.

    2010-01-01

    A prototype miniature bioreactor system is designed to serve as a laboratory benchtop cell-culturing system that minimizes the need for relatively expensive equipment and reagents and can be operated under computer control, thereby reducing the time and effort required of human investigators and reducing uncertainty in results. The system includes a bioreactor, a fluid-handling subsystem, a chamber wherein the bioreactor is maintained in a controlled atmosphere at a controlled temperature, and associated control subsystems. The system can be used to culture both anchorage-dependent and suspension cells, which can be either prokaryotic or eukaryotic. Cells can be cultured for extended periods of time in this system, and samples of cells can be extracted and analyzed at specified intervals. By integrating this system with one or more microanalytical instrument(s), one can construct a complete automated analytical system that can be tailored to perform one or more of a large variety of assays.

  3. Sensor equipment for quantification of spatial heterogeneity in large bioreactor

    DEFF Research Database (Denmark)

    Nørregaard, Anders; Formenti, Luca Riccardo; Stocks, Stuart M.;

    Suspension cultivation in large stirred tank reactors suffers from imperfect mixing and pressure gradients due to the large size of the liquid column in the bioreactors. This leads to gradients of substrate concentrations and in turn cell population heterogeneity. The processes in large scale...... cannot be directly compared to laboratory scale experiments due to these reasons, and thus, in order to understand the large scale processes, experimental data has to be collected at large scale. The cost of acquiring data at large scale is high. The bioreactors are usually run with a limited array...... of sensors and in order to apply more sensor equipment the bioreactor has to be modified which is both costly and results in production downtime. The presence of three phases (gas, liquid, and solid), and the opaque nature of the fermentation broth together with the necessity of heat sterilization further...

  4. Streamlined bioreactor-based production of human cartilage tissues.

    Science.gov (United States)

    Tonnarelli, B; Santoro, R; Adelaide Asnaghi, M; Wendt, D

    2016-05-27

    Engineered tissue grafts have been manufactured using methods based predominantly on traditional labour-intensive manual benchtop techniques. These methods impart significant regulatory and economic challenges, hindering the successful translation of engineered tissue products to the clinic. Alternatively, bioreactor-based production systems have the potential to overcome such limitations. In this work, we present an innovative manufacturing approach to engineer cartilage tissue within a single bioreactor system, starting from freshly isolated human primary chondrocytes, through the generation of cartilaginous tissue grafts. The limited number of primary chondrocytes that can be isolated from a small clinically-sized cartilage biopsy could be seeded and extensively expanded directly within a 3D scaffold in our perfusion bioreactor (5.4 ± 0.9 doublings in 2 weeks), bypassing conventional 2D expansion in flasks. Chondrocytes expanded in 3D scaffolds better maintained a chondrogenic phenotype than chondrocytes expanded on plastic flasks (collagen type II mRNA, 18-fold; Sox-9, 11-fold). After this "3D expansion" phase, bioreactor culture conditions were changed to subsequently support chondrogenic differentiation for two weeks. Engineered tissues based on 3D-expanded chondrocytes were more cartilaginous than tissues generated from chondrocytes previously expanded in flasks. We then demonstrated that this streamlined bioreactor-based process could be adapted to effectively generate up-scaled cartilage grafts in a size with clinical relevance (50 mm diameter). Streamlined and robust tissue engineering processes, as the one described here, may be key for the future manufacturing of grafts for clinical applications, as they facilitate the establishment of compact and closed bioreactor-based production systems, with minimal automation requirements, lower operating costs, and increased compliance to regulatory guidelines.

  5. Streamlined bioreactor-based production of human cartilage tissues.

    Science.gov (United States)

    Tonnarelli, B; Santoro, R; Adelaide Asnaghi, M; Wendt, D

    2016-01-01

    Engineered tissue grafts have been manufactured using methods based predominantly on traditional labour-intensive manual benchtop techniques. These methods impart significant regulatory and economic challenges, hindering the successful translation of engineered tissue products to the clinic. Alternatively, bioreactor-based production systems have the potential to overcome such limitations. In this work, we present an innovative manufacturing approach to engineer cartilage tissue within a single bioreactor system, starting from freshly isolated human primary chondrocytes, through the generation of cartilaginous tissue grafts. The limited number of primary chondrocytes that can be isolated from a small clinically-sized cartilage biopsy could be seeded and extensively expanded directly within a 3D scaffold in our perfusion bioreactor (5.4 ± 0.9 doublings in 2 weeks), bypassing conventional 2D expansion in flasks. Chondrocytes expanded in 3D scaffolds better maintained a chondrogenic phenotype than chondrocytes expanded on plastic flasks (collagen type II mRNA, 18-fold; Sox-9, 11-fold). After this "3D expansion" phase, bioreactor culture conditions were changed to subsequently support chondrogenic differentiation for two weeks. Engineered tissues based on 3D-expanded chondrocytes were more cartilaginous than tissues generated from chondrocytes previously expanded in flasks. We then demonstrated that this streamlined bioreactor-based process could be adapted to effectively generate up-scaled cartilage grafts in a size with clinical relevance (50 mm diameter). Streamlined and robust tissue engineering processes, as the one described here, may be key for the future manufacturing of grafts for clinical applications, as they facilitate the establishment of compact and closed bioreactor-based production systems, with minimal automation requirements, lower operating costs, and increased compliance to regulatory guidelines. PMID:27232665

  6. Biological reduction of nitrate wastewater using fluidized-bed bioreactors

    International Nuclear Information System (INIS)

    There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO3- and as large as 2000 m3/d, in the nuclear fuel cycle as well as in many commercial processes such as fertilizer production, paper manufacturing, and metal finishing. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 gN(NO3-)/m3 by the use of a fluidized-bed bioreactor. The major strain of denitrification bacteria is Pseudomonas which was derived from garden soil. In the fluidized-bed bioreactor the bacteria are allowed to attach to 0.25 to 0.50-mm-diam coal particles, which are fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m3. A description is given of the results of two biodenitrification R and D pilot plant programs based on the use of fluidized bioreactors capable of operating at nitrate levels up to 7000 g/m3 and achieving denitrification rates as high as 80 gN(NO3-)/d per liter of empty bioreactor volume. The first of these pilot plant programs consisted of two 0.2-m-diam bioreactors, each with a height of 6.3 m and a volume of 208 liters, operating in series. The second pilot plant was used to determine the diameter dependence of the reactors by using a 0.5-m-diam reactor with a height of 6.3 m and a volume of 1200 liters. These pilot plants operated for a period of six months and two months respectively, while using both a synthetic waste and the actual waste from a gaseous diffusion plant operated by Goodyear Atomic Corporation

  7. Study of metabolic pathways for hydrogen production in chlamydomonas reinhardtii and transposition on a torus photo bioreactor

    International Nuclear Information System (INIS)

    Considering the recent increase in energy consumption. aide associated environmental risks, new trails are followed today to develop the use of clean and renewable alternative energies. In this context hydrogen seems to be a serious solution and this study, based on micro-algae photosynthetic capacities exploitation, will allow to devise a process for hydrogen production from only water and solar energy without greenhouse gas release. The sulphur deprivation protocol on TAP medium, known to lead to hydrogen production in Chlamydomonas reinhardtii species was particularly studied. At the metabolic level, two important phenomena are induced under these conditions: an over-accumulation of the intracellular starch reserves and a simultaneous alteration of the PsII activity which leads to anoxia and Fe-hydrogenase induction, an enzyme with a strong specific activity responsible for the hydrogen production. The contribution of the two electron transfer pathways implied in the hydrogen production process (PsII-dependent and PSII-independent) as well as the importance of the previously accumulated starch were highlighted here. We also investigated the potential for designing autotrophic protocols for hydrogen photoproduction. Various protocols, considered to be relevant, were then transposed on a torus photo-bioreactor, specifically developed in this study and which allows the control of culture parameters as well as the precise measurement of gas release kinetics, in order to obtain first estimates of productivity of the system. Integration of the physical; aspects of the pilot and biological aspects of the process in a model, finally opens new prospects for subject development, in particular for a reasoned optimization of hydrogen production via this double physiology/process approach. (author)

  8. Removal of steroid estrogens from municipal wastewater in a pilot scale expanded granular sludge blanket reactor and anaerobic membrane bioreactor

    Science.gov (United States)

    Ito, Ayumi; Mensah, Lawson; Cartmell, Elise; Lester, John N.

    2016-01-01

    Anaerobic treatment of municipal wastewater offers the prospect of a new paradigm by reducing aeration costs and minimizing sludge production. It has been successfully applied in warm climates, but does not always achieve the desired outcomes in temperate climates at the biochemical oxygen demand (BOD) values of municipal crude wastewater. Recently the concept of ‘fortification' has been proposed to increase organic strength and has been demonstrated at the laboratory and pilot scale treating municipal wastewater at temperatures of 10–17°C. The process treats a proportion of the flow anaerobically by combining it with primary sludge from the residual flow and then polishing it to a high effluent standard aerobically. Energy consumption is reduced as is sludge production. However, no new treatment process is viable if it only addresses the problems of traditional pollutants (suspended solids – SS, BOD, nitrogen – N and phosphorus – P); it must also treat hazardous substances. This study compared three potential municipal anaerobic treatment regimes, crude wastewater in an expanded granular sludge blanket (EGSB) reactor, fortified crude wastewater in an EGSB and crude wastewater in an anaerobic membrane bioreactor. The benefits of fortification were demonstrated for the removal of SS, BOD, N and P. These three systems were further challenged with the removal of steroid estrogens at environmental concentrations from natural indigenous sources. All three systems removed these compounds to a significant degree, confirming that estrogen removal is not restricted to highly aerobic autotrophs, or aerobic heterotrophs, but is also a faculty of anaerobic bacteria. PMID:26212345

  9. BIOREACTOR WITH LID FOR EASY ACCESS TO INCUBATION CAVITY

    DEFF Research Database (Denmark)

    2012-01-01

    There is provided a bioreactor which is provided with a lid (13) that facilitates access to the incubation cavity. Specifically the end wall of the incubation cavity is constituted by the lid (13) so that removal of the cap renders the incubation cavity fully accessible.......There is provided a bioreactor which is provided with a lid (13) that facilitates access to the incubation cavity. Specifically the end wall of the incubation cavity is constituted by the lid (13) so that removal of the cap renders the incubation cavity fully accessible....

  10. Over-pressurized bioreactors: application to microbial cell cultures.

    Science.gov (United States)

    Lopes, Marlene; Belo, Isabel; Mota, Manuel

    2014-01-01

    In industrial biotechnology, microbial cultures are exposed to different local pressures inside bioreactors. Depending on the microbial species and strains, the increased pressure may have detrimental or beneficial effects on cellular growth and product formation. In this review, the effects of increased air pressure on various microbial cultures growing in bioreactors under moderate total pressure conditions (maximum, 15 bar) will be discussed. Recent data illustrating the diversity of increased air pressure effects at different levels in microbial cells cultivation will be presented, with particular attention to the effects of oxygen and carbon dioxide partial pressures on cellular growth and product formation, and the concomitant effect of oxygen pressure on antioxidant cellular defense mechanisms.

  11. ANAEROBIC MEMBRANE BIOREACTORS FOR DOMESTIC WASTEWATER TREATMENT. PRELIMINARY STUDY

    Directory of Open Access Journals (Sweden)

    Luisa Vera

    2014-12-01

    Full Text Available The operation of submerged anaerobic membrane bioreactors (SAnMBRs for domestic wastewaters treatment was studied in laboratory scale, with the objective to define sustainable filtration conditions of the suspensions along the process. During continuous experiments, the organic matter degradation by anaerobic way showed an average DQOT removal of 85% and 93%. Indeed, the degradation generated biogas after 12 days of operation and its relative methane composition was of 60% after 25 days of operation. Additionally, the comparison between membrane bioreactors (MBRs performance in aerobic and anaerobic conditions in filterability terms, reported that both systems behave similarly once reached the stationary state.

  12. Thawing permafrost increases old soil and autotrophic respiration in tundra: partitioning ecosystem respiration using δ(13) C and ∆(14) C.

    Science.gov (United States)

    Hicks Pries, Caitlin E; Schuur, Edward A G; Crummer, Kathryn G

    2013-02-01

    Ecosystem respiration (Reco ) is one of the largest terrestrial carbon (C) fluxes. The effect of climate change on Reco depends on the responses of its autotrophic and heterotrophic components. How autotrophic and heterotrophic respiration sources respond to climate change is especially important in ecosystems underlain by permafrost. Permafrost ecosystems contain vast stores of soil C (1672 Pg) and are located in northern latitudes where climate change is accelerated. Warming will cause a positive feedback to climate change if heterotrophic respiration increases without corresponding increases in primary production. We quantified the response of autotrophic and heterotrophic respiration to permafrost thaw across the 2008 and 2009 growing seasons. We partitioned Reco using Δ(14) C and δ(13) C into four sources-two autotrophic (above - and belowground plant structures) and two heterotrophic (young and old soil). We sampled the Δ(14) C and δ(13) C of sources using incubations and the Δ(14) C and δ(13) C of Reco using field measurements. We then used a Bayesian mixing model to solve for the most likely contributions of each source to Reco . Autotrophic respiration ranged from 40 to 70% of Reco and was greatest at the height of the growing season. Old soil heterotrophic respiration ranged from 6 to 18% of Reco and was greatest where permafrost thaw was deepest. Overall, growing season fluxes of autotrophic and old soil heterotrophic respiration increased as permafrost thaw deepened. Areas with greater thaw also had the greatest primary production. Warming in permafrost ecosystems therefore leads to increased plant and old soil respiration that is initially compensated by increased net primary productivity. However, barring large shifts in plant community composition, future increases in old soil respiration will likely outpace productivity, resulting in a positive feedback to climate change. PMID:23504799

  13. 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.

  14. 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

  15. The autotrophic contribution to soil respiration in a northern temperate deciduous forest and its response to stand disturbance.

    Science.gov (United States)

    Levy-Varon, Jennifer H; Schuster, William S F; Griffin, Kevin L

    2012-05-01

    The goal of this study was to evaluate the contribution of oak trees (Quercus spp.) and their associated mycorrhizal fungi to total community soil respiration in a deciduous forest (Black Rock Forest) and to explore the partitioning of autotrophic and heterotrophic respiration. Trees on twelve 75 × 75-m plots were girdled according to four treatments: girdling all the oaks on the plot (OG), girdling half of the oak trees on a plot (O50), girdling all non-oaks on a plot (NO), and a control (C). In addition, one circular plot (diameter 50 m) was created where all trees were girdled (ALL). Soil respiration was measured before and after tree girdling. A conservative estimate of the total autotrophic contribution is approximately 50%, as indicated by results on the ALL and OG plots. Rapid declines in carbon dioxide (CO(2)) flux from both the ALL and OG plots, 37 and 33%, respectively, were observed within 2 weeks following the treatment, demonstrating a fast turnover of recently fixed carbon. Responses from the NO and O50 treatments were statistically similar to the control. A non-proportional decline in respiration rates along the gradient of change in live aboveground biomass complicated partitioning of the overall rate of soil respiration and indicates that belowground carbon flux is not linearly related to aboveground disturbance. Our findings suggest that in this system there is a threshold disturbance level between 35 and 74% of live aboveground biomass loss, beyond which belowground dynamics change dramatically.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. The role of pyruvate ferredoxin oxidoreductase in pyruvate synthesis during autotrophic growth by the Wood-Ljungdahl pathway.

    Science.gov (United States)

    Furdui, C; Ragsdale, S W

    2000-09-15

    Pyruvate:ferredoxin oxidoreductase (PFOR) catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA and CO(2). The catalytic proficiency of this enzyme for the reverse reaction, pyruvate synthase, is poorly understood. Conversion of acetyl-CoA to pyruvate links the Wood-Ljungdahl pathway of autotrophic CO(2) fixation to the reductive tricarboxylic acid cycle, which in these autotrophic anaerobes is the stage for biosynthesis of all cellular macromolecules. The results described here demonstrate that the Clostridium thermoaceticum PFOR is a highly efficient pyruvate synthase. The Michaelis-Menten parameters for pyruvate synthesis by PFOR are: V(max) = 1.6 unit/mg (k(cat) = 3.2 s(-1)), K(m)(Acetyl-CoA) = 9 micrometer, and K(m)(CO(2)) = 2 mm. The intracellular concentrations of acetyl-CoA, CoASH, and pyruvate have been measured. The predicted rate of pyruvate synthesis at physiological concentrations of substrates clearly is sufficient to support the role of PFOR as a pyruvate synthase in vivo. Measurements of its k(cat)/K(m) values demonstrate that ferredoxin is a highly efficient electron carrier in both the oxidative and reductive reactions. On the other hand, rubredoxin is a poor substitute in the oxidative direction and is inept in donating electrons for pyruvate synthesis. PMID:10878009

  1. Hydrofocusing Bioreactor Produces Anti-Cancer Alkaloids

    Science.gov (United States)

    Gonda, Steve R.; Valluri, Jagan V.

    2011-01-01

    A methodology for growing three-dimensional plant tissue models in a hydrodynamic focusing bioreactor (HFB) has been developed. The methodology is expected to be widely applicable, both on Earth and in outer space, as a means of growing plant cells and aggregates thereof under controlled conditions for diverse purposes, including research on effects of gravitation and other environmental factors upon plant growth and utilization of plant tissue cultures to produce drugs in quantities greater and at costs lower than those of conventional methodologies. The HFB was described in Hydro focus - ing Bioreactor for Three-Dimensional Cell Culture (MSC-22358), NASA Tech Briefs, Vol. 27, No. 3 (March 2003), page 66. To recapitulate: The HFB offers a unique hydrofocusing capability that enables the creation of a low-shear liquid culture environment simultaneously with the herding of suspended cells and tissue assemblies and removal of unwanted air bubbles. The HFB includes a rotating cell-culture vessel with a centrally located sampling port and an internal rotating viscous spinner attached to a rotating base. The vessel and viscous spinner can be made to rotate at the same speed and direction or different speeds and directions to tailor the flow field and the associated hydrodynamic forces in the vessel in order to obtain low-shear suspension of cells and control of the locations of cells and air bubbles. For research and pharmaceutical-production applications, the HFB offers two major benefits: low shear stress, which promotes the assembly of cells into tissue-like three-dimensional constructs; and randomization of gravitational vectors relative to cells, which affects production of medicinal compounds. Presumably, apposition of plant cells in the absence of shear forces promotes cell-cell contacts, cell aggregation, and cell differentiation. Only gentle mixing is necessary for distributing nutrients and oxygen. It has been postulated that inasmuch as cells in the simulated

  2. A comparison of bioreactors for culture of fetal mesenchymal stem cells for bone tissue engineering.

    Science.gov (United States)

    Zhang, Zhi-Yong; Teoh, Swee Hin; Teo, Erin Yiling; Khoon Chong, Mark Seow; Shin, Chong Woon; Tien, Foo Toon; Choolani, Mahesh A; Chan, Jerry K Y

    2010-11-01

    Bioreactors provide a dynamic culture system for efficient exchange of nutrients and mechanical stimulus necessary for the generation of effective tissue engineered bone grafts (TEBG). We have shown that biaxial rotating (BXR) bioreactor-matured human fetal mesenchymal stem cell (hfMSC) mediated-TEBG can heal a rat critical sized femoral defect. However, it is not known whether optimal bioreactors exist for bone TE (BTE) applications. We systematically compared this BXR bioreactor with three most commonly used systems: Spinner Flask (SF), Perfusion and Rotating Wall Vessel (RWV) bioreactors, for their application in BTE. The BXR bioreactor achieved higher levels of cellularity and confluence (1.4-2.5x, p bioreactors operating in optimal settings. BXR bioreactor-treated scaffolds experienced earlier and more robust osteogenic differentiation on von Kossa staining, ALP induction (1.2-1.6×, p bioreactor-treated grafts, but not with the other three. BXR bioreactor enabled superior cellular proliferation, spatial distribution and osteogenic induction of hfMSC over other commonly used bioreactors. In addition, we developed and validated a non-invasive quantitative micro CT-based technique for analyzing neo-tissue formation and its spatial distribution within scaffolds.

  3. Purifying effects of enhanced bioreactor on the wastewater in recirculating aquaculture systems%生物强化反应器净化循环养殖废水的研究

    Institute of Scientific and Technical Information of China (English)

    钱伟; 陆开宏; 郑忠明; 吕镇梅; 谢丽凤; 张克鑫

    2011-01-01

    An enhanced bioreactor was designed according to the highly effective interception principle of biofilm in recirculating aquaculture systems (RAS)by inoculating nitrifying and denitrifying bacteria to the elastic fiber carriers on which biofilms could be observed in situ 6 weeks after inoculating. The impact of hydraulic retention time (HRT) and water temperature (WT) on the purifying effects of enhanced bioreactor on wastewater of RAS was investigated. The result showed that HRT and WT significantly impacted the purifying effect of the bioreactor on wastewater( P < 0.05). After analysis of significant differences between HRT and WT within removal rate of CODMn, TN and NH+4 -N, and considering run-time, cost and operational easiness of bioreactor,it was concluded that 18 h of HRT and 30 ℃ were the best operating conditions. The bioreactor was operated stably for 25 days under these conditions, the average removal rate of CODMn, TN and NH+4-N reached 44.18% ,51.31% and 82.08%, respectively. In addition, the cultivable microorganisms in the biofilm of the enhanced bioreactor were detected regularly throughout the 25 days of experimental time. As the biofilm developed, the biomass of all kinds of cultivable microorganisms rose, average levels of nitrifying bacteria grew from 35.91 × 104 CFU/mg to 89.43 × 104 CFU/mg, nitroso-bacteria from 25.75 × 104 CFU/mg to 61.65 × 104 CFU/mg and denitrifying bacteria from 14.23 × 104 CFU/mg to 100.95 × 104 CFU/mg. Nitrifying and nitroso-bacteria dominated among cultivable microorganisms(59.95% -81.25% ).Denitrifying bacteria were constantly adsorbed, colonized and successfully reproduced on the surface of elastic fiber carriers, which made biofilms more mature and stable (the removal rate of TN and NH+4-N reached respectively 51. 31% and 82. 08% ). The results of present study revealed that the enhanced bioreactor plays an important role in the removal of CODMn, TN and NH+4 -N in wastewater of RAS.%利用

  4. 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

  5. A sensitive crude oil bioassay indicates that oil spills potentially induce a change of major nitrifying prokaryotes from the Archaea to the Bacteria

    International Nuclear Information System (INIS)

    The sensitivity of nitrifiers to crude oil released by the BP Deepwater Horizon oil spill in Gulf of Mexico was examined using characterized ammonia-oxidizing bacteria and archaea to develop a bioassay and to gain further insight into the ecological response of these two groups of microorganisms to marine oil spills. Inhibition of nitrite production was observed among all the tested ammonia-oxidizing organisms at 100 ppb crude oil. Nitrosopumilus maritimus, a cultured representative of the abundant Marine Group I Archaea, showed 20% inhibition at 1 ppb, a much greater degree of sensitivity to petroleum than the tested ammonia-oxidizing and heterotrophic bacteria. The differing susceptibility may have ecological significance since a shift to bacterial dominance in response to an oil spill could potentially persist and alter trophic interactions influenced by availability of different nitrogen species. - Oil spills potentially induce a change of major nitrifying prokaryotes from the archaea to the bacteria.

  6. Effect of carbon source on acclimatization of nitrifying bacteria to achieve high-rate partial nitrification of wastewater with high ammonium concentration

    Science.gov (United States)

    Mousavi, Seyyed Alireza; Ibrahim, Shaliza; Aroua, Mohamed Kheireddine

    2014-08-01

    Experiments in two laboratory-scale sequential batch reactors were carried out to investigate the effect of heterotrophic bacteria on nitrifying bacteria using external carbon sources. Partial nitrification of ammonium-rich wastewater during short-term acclimatization enriched the activity of ammonia-oxidizing bacteria in both reactors. Heterotrophic bacteria exhibited a minor effect on nitrifying bacteria, and complete removal of ammonium occurred at a rate of 41 mg L-1 h-1 in both reactors. The main strategy of this research was to carry out partial nitrification using high-activity ammonia-oxidizing bacteria with a high concentration of free ammonia (70 mg L-1). The NO2 -/(NO3 - + NO2 -) ratio was greater than 0.9 in both reactors most of the time.

  7. Introducing Textiles as Material of Construction of Ethanol Bioreactors

    Directory of Open Access Journals (Sweden)

    Osagie A. Osadolor

    2014-11-01

    Full Text Available The conventional materials for constructing bioreactors for ethanol production are stainless and cladded carbon steel because of the corrosive behaviour of the fermenting media. As an alternative and cheaper material of construction, a novel textile bioreactor was developed and examined. The textile, coated with several layers to withstand the pressure, resist the chemicals inside the reactor and to be gas-proof was welded to form a 30 L lab reactor. The reactor had excellent performance for fermentative production of bioethanol from sugar using baker’s yeast. Experiments with temperature and mixing as process parameters were performed. No bacterial contamination was observed. Bioethanol was produced for all conditions considered with the optimum fermentation time of 15 h and ethanol yield of 0.48 g/g sucrose. The need for mixing and temperature control can be eliminated. Using a textile bioreactor at room temperature of 22 °C without mixing required 2.5 times longer retention time to produce bioethanol than at 30 °C with mixing. This will reduce the fermentation investment cost by 26% for an ethanol plant with capacity of 100,000 m3 ethanol/y. Also, replacing one 1300 m3 stainless steel reactor with 1300 m3 of the textile bioreactor in this plant will reduce the fermentation investment cost by 19%.

  8. Modelling and characterization of an airlift-loop bioreactor.

    NARCIS (Netherlands)

    Verlaan, P.

    1987-01-01

    An airlift-loop reactor is a bioreactor for aerobic biotechnological processes. The special feature of the ALR is the recirculation of the liquid through a downcomer connecting the top and the bottom of the main bubbling section. Due to the high circulation-flow rate, efficient mixing and oxygen tra

  9. Anaerobic Membrane Bioreactors For Cost-Effective Municipal Water Reuse

    NARCIS (Netherlands)

    Özgün, H.

    2015-01-01

    In recent years, anaerobic membrane bioreactor (AnMBR) technology has been increasingly researched for municipal wastewater treatment as a means to produce nutrient-rich, solids free effluents with low levels of pathogens, while occupying a small footprint. An AnMBR can be used not only for on-site

  10. 40 CFR 258.41 - Project XL Bioreactor Landfill Projects.

    Science.gov (United States)

    2010-07-01

    ... WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Design Criteria § 258.41 Project XL Bioreactor... reference with 5 U.S.C. 552(a) and 1 CFR part 51. These methods are available from The American Society for... landfills operated by the Waste Management, Inc. or its successors: The Maplewood Recycling and...

  11. Reduced Order Dead-Beat Observers for a Bioreactor

    CERN Document Server

    Karafyllis, Iasson

    2010-01-01

    This paper studies the strong observability property and the reduced-order dead-beat observer design problem for a continuous bioreactor. New relationships between coexistence and strong observability, and checkable sufficient conditions for strong observability, are established for a chemostat with two competing microbial species. Furthermore, the dynamic output feedback stabilization problem is solved for the case of one species.

  12. Numerical study of fluid motion in bioreactor with two mixers

    Energy Technology Data Exchange (ETDEWEB)

    Zheleva, I., E-mail: izheleva@uni-ruse.bg [Department of Heat Technology, Hydraulics and Ecology, Angel Kanchev University of Rousse, 8 Studentska str., 7017 Rousse (Bulgaria); Lecheva, A., E-mail: alecheva@uni-ruse.bg [Department of Mathematics, Angel Kanchev University of Rousse, 8 Studentska str., 7017 Rousse (Bulgaria)

    2015-10-28

    Numerical study of hydrodynamic laminar behavior of a viscous fluid in bioreactor with multiple mixers is provided in the present paper. The reactor is equipped with two disk impellers. The fluid motion is studied in stream function-vorticity formulation. The calculations are made by a computer program, written in MATLAB. The fluid structure is described and numerical results are graphically presented and commented.

  13. NASA's Bioreactor: Growing Cells in a Microgravity Environment. Educational Brief.

    Science.gov (United States)

    National Aeronautics and Space Administration, Washington, DC.

    This brief discusses growing cells in a microgravity environment for grades 9-12. Students are provided with plans for building a classroom bioreactor that can then be used with the included activity on seed growth in a microgravity environment. Additional experimental ideas are also suggested along with a history and background on microgravity…

  14. Hydraulic flow characteristics of agricultural residues for denitrifying bioreactor media

    Science.gov (United States)

    Denitrifying bioreactors are a promising technology to mitigate agricultural subsurface drainage nitrate-nitrogen losses, a critical water quality goal for the Upper Mississippi River Basin. This study was conducted to evaluate the hydraulic properties of agricultural residues that are potential bio...

  15. MEASUREMENT OF FUGITIVE EMISSIONS AT A BIOREACTOR LANDFILL

    Science.gov (United States)

    This report focuses on three field campaigns performed in 2002 and 2003 to measure fugitive emissions at a bioreactor landfill in Louisville, KY, using an open-path Fourier transform infrared spectrometer. The study uses optical remote sensing-radial plume mapping. The horizontal...

  16. Simulating woodchip bioreactor performance using a dual-porosity model

    Science.gov (United States)

    Nitrate in the Nation's surface waters has been a persistent health and ecological problem. The major source of nitrate is tile drainage from agricultural row crops. Denitrification bioreactors have been shown to be effective in removing much of the nitrate from tile drains. While we understand i...

  17. Optimising Microbial Growth with a Bench-Top Bioreactor

    Science.gov (United States)

    Baker, A. M. R.; Borin, S. L.; Chooi, K. P.; Huang, S. S.; Newgas, A. J. S.; Sodagar, D.; Ziegler, C. A.; Chan, G. H. T.; Walsh, K. A. P.

    2006-01-01

    The effects of impeller size, agitation and aeration on the rate of yeast growth were investigated using bench-top bioreactors. This exercise, carried out over a six-month period, served as an effective demonstration of the importance of different operating parameters on cell growth and provided a means of determining the optimisation conditions…

  18. Performance of Submerged Membrane Bioreactor for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present research, a submerged membrane bioreactor was tested to treat domestic wastewater. Three experimental runs were conducted all with a hydraulic retention time of 5h and sludge retention times (SRTs) of 5, 10, and 20 d. The pollutant removal performance of the membrane bioreactor, the membrane effluent quality, and a kinetic model for sludge growth in the bioreactor were investigated. The combined process was capable of removing over 90% of both COD (chemical oxygen demand) and NH3-N on the average. The total removal for COD was almost independent of SRT, but that for NH3-N improved with increasing SRT. Membrane effluent quality meets the water quality standard for reuse issued by the Ministry of Construction of China. Increasing SRT causes the concentrations of suspended solids (SS) and volatile suspended solids (VSS) in the bioreactor to increase. However, the ratio of VSS/SS did not change much. Kinetic analysis showed that the sludge yield coefficient (kg-VSS·kg-COD-1) and the endogenous coefficient of microorganisms were 0.25 and 0.04d-1, which are similar to those of the conventional activated sludge process.

  19. Internal hydraulics of an agricultural drainage denitrification bioreactor

    Science.gov (United States)

    Denitrification bioreactors to reduce the amount of nitrate-nitrogen in agricultural drainage are now being deployed across the U.S. Midwest. However, there are still many unknowns regarding internal hydraulic-driven processes in these "black box" engineered treatment systems. To improve this unders...

  20. Expression Systems and Species Used for Transgenic Animal Bioreactors

    Directory of Open Access Journals (Sweden)

    Yanli Wang

    2013-01-01

    Full Text Available Transgenic animal bioreactors can produce therapeutic proteins with high value for pharmaceutical use. In this paper, we compared different systems capable of producing therapeutic proteins (bacteria, mammalian cells, transgenic plants, and transgenic animals and found that transgenic animals were potentially ideal bioreactors for the synthesis of pharmaceutical protein complexes. Compared with other transgenic animal expression systems (egg white, blood, urine, seminal plasma, and silkworm cocoon, the mammary glands of transgenic animals have enormous potential. Compared with other mammalian species (pig, goat, sheep, and cow that are currently being studied as bioreactors, rabbits offer many advantages: high fertility, easy generation of transgenic founders and offspring, insensitivity to prion diseases, relatively high milk production, and no transmission of severe diseases to humans. Noticeably, for a small- or medium-sized facility, the rabbit system is ideal to produce up to 50 kg of protein per year, considering both economical and hygienic aspects; rabbits are attractive candidates for the mammary-gland-specific expression of recombinant proteins. We also reviewed recombinant proteins that have been produced by targeted expression in the mammary glands of rabbits and discussed the limitations of transgenic animal bioreactors.

  1. Bioreactors for removing methyl bromide following contained fumigations

    Science.gov (United States)

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

    2003-01-01

    Use of methyl bromide (MeBr) as a quarantine, commodity, or structural fumigant is under scrutiny because its release to the atmosphere contributes to the depletion of stratospheric ozone. A closed-system bioreactor consisting of 0.5 L of a growing culture of a previously described bacterium, strain IMB-1, removed MeBr (> 110 ??mol L-1) from recirculating air. Strain IMB-1 grew slowly to high cell densities in the bioreactor using MeBr as its sole carbon and energy source. Bacterial oxidation of MeBr produced CO2 and hydrobromic acid (HBr), which required continuous neutralization with NaOH for the system to operate effectively. Strain IMB-1 was capable of sustained oxidation of large amounts of MeBr (170 mmol in 46 d). In an open-system bioreactor (10-L fermenter), strain IMB-1 oxidized a continuous supply of MeBr (220 ??mol L-1 in air). Growth was continuous, and 0.5 mol of MeBr was removed from the air supply in 14 d. The specific rate of MeBr oxidation was 7 ?? 10-16 mol cell-1 h-1. Bioreactors such as these can therefore be used to remove large quantities of contaminant MeBr, which opens the possibility of biodegradation as a practical means for its disposal.

  2. Oxygen Sensors Monitor Bioreactors and Ensure Health and Safety

    Science.gov (United States)

    2014-01-01

    In order to cultivate healthy bacteria in bioreactors, Kennedy Space Center awarded SBIR funding to Needham Heights, Massachusetts-based Polestar Technologies Inc. to develop sensors that could monitor oxygen levels. The result is a sensor now widely used by pharmaceutical companies and medical research universities. Other sensors have also been developed, and in 2013 alone the company increased its workforce by 50 percent.

  3. Gel layer formation on membranes in Membrane Bioreactors

    NARCIS (Netherlands)

    Van den Brink, P.F.H.

    2014-01-01

    The widespread application of membrane bioreactors (MBRs) for municipal wastewater treatment is hampered by membrane fouling. Fouling increases energy demand, reduces process performance and creates the need for more frequent (chemical) membrane cleaning or replacement. Membrane fouling in MBRs is k

  4. Microfluidic bioreactors for culture of non-adherent cells

    DEFF Research Database (Denmark)

    Shah, Pranjul Jaykumar; Vedarethinam, Indumathi; Kwasny, Dorota;

    2011-01-01

    Microfluidic bioreactors (μBR) are becoming increasingly popular for cell culture, sample preparation and analysis in case of routine genetic and clinical diagnostics. We present a novel μBR for non-adherent cells designed to mimic in vivo perfusion of cells based on diffusion of media through...

  5. Thermophillic Sidestream Anaerobic Membrane Bioreactors: The Shear Rate Dilemma

    NARCIS (Netherlands)

    Jeison, D.A.; Telkamp, P.; Lier, van J.B.

    2009-01-01

    Anaerobic biomass retention under thermophilic conditions has proven difficult. Membrane filtration can be used as alternative way to achieve high sludge concentrations. This research studied the feasibility of anaerobic membrane bioreactors (AnMBRs) under thermophilic conditions. A sidestream MBR w

  6. Expansion of Human Mesenchymal Stem Cells in a Microcarrier Bioreactor.

    Science.gov (United States)

    Tsai, Ang-Chen; Ma, Teng

    2016-01-01

    Human mesenchymal stem cells (hMSCs) are considered as a primary candidate in cell therapy owing to their self-renewability, high differentiation capabilities, and secretions of trophic factors. In clinical application, a large quantity of therapeutically competent hMSCs is required that cannot be produced in conventional petri dish culture. Bioreactors are scalable and have the capacity to meet the production demand. Microcarrier suspension culture in stirred-tank bioreactors is the most widely used method to expand anchorage dependent cells in a large scale. Stirred-tank bioreactors have the potential to scale up and microcarriers provide the high surface-volume ratio. As a result, a spinner flask bioreactor with microcarriers has been commonly used in large scale expansion of adherent cells. This chapter describes a detailed culture protocol for hMSC expansion in a 125 mL spinner flask using microcarriers, Cytodex I, and a procedure for cell seeding, expansion, metabolic sampling, and quantification and visualization using microculture tetrazolium (MTT) reagent. PMID:27032950

  7. Anammox enrichment from reject water on blank biofilm carriers and carriers containing nitrifying biomass: operation of two moving bed biofilm reactors (MBBR).

    Science.gov (United States)

    Zekker, Ivar; Rikmann, Ergo; Tenno, Toomas; Lemmiksoo, Vallo; Menert, Anne; Loorits, Liis; Vabamäe, Priit; Tomingas, Martin; Tenno, Taavo

    2012-07-01

    The anammox bacteria were enriched from reject water of anaerobic digestion of municipal wastewater sludge onto moving bed biofilm reactor (MBBR) system carriers-the ones initially containing no biomass (MBBR1) as well as the ones containing nitrifying biomass (MBBR2). Duration of start-up periods of the both reactors was similar (about 100 days), but stable total nitrogen (TN) removal efficiency occurred earlier in the system containing nitrifying biomass. Anammox TN removal efficiency of 70% was achieved by 180 days in both 20 l volume reactors at moderate temperature of 26.0°C. During the steady state phase of operation of MBBRs the average TN removal efficiencies and maximum TN removal rates in MBBR1 were 80% (1,000 g-N/m(3)/day, achieved by 308 days) and in MBBR2 85% (1,100 g-N/m(3)/day, achieved by 266 days). In both reactors mixed bacterial cultures were detected. Uncultured Planctomycetales bacterium clone P4, Candidatus Nitrospira defluvii and uncultured Nitrospira sp. clone 53 were identified by PCR-DGGE from the system initially containing blank biofilm carriers as well as from the nitrifying biofilm system; from the latter in addition to these also uncultured ammonium oxidizing bacterium clone W1 and Nitrospira sp. clone S1-62 were detected. FISH analysis revealed that anammox microorganisms were located in clusters in the biofilm. Using previously grown nitrifying biofilm matrix for anammox enrichment has some benefits over starting up the process from zero, such as less time for enrichment and protection against severe inhibitions in case of high substrate loading rates.

  8. Soil environmental conditions and microbial build-up mediate the effect of plant diversity on soil nitrifying and denitrifying enzyme activities in temperate grasslands.

    Directory of Open Access Journals (Sweden)

    Xavier Le Roux

    Full Text Available Random reductions in plant diversity can affect ecosystem functioning, but it is still unclear which components of plant diversity (species number - namely richness, presence of particular plant functional groups, or particular combinations of these and associated biotic and abiotic drivers explain the observed relationships, particularly for soil processes. We assembled grassland communities including 1 to 16 plant species with a factorial separation of the effects of richness and functional group composition to analyze how plant diversity components influence soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively, the abundance of nitrifiers (bacterial and archaeal amoA gene number and denitrifiers (nirK, nirS and nosZ gene number, and key soil environmental conditions. Plant diversity effects were largely due to differences in functional group composition between communities of identical richness (number of sown species, though richness also had an effect per se. NEA was positively related to the percentage of legumes in terms of sown species number, the additional effect of richness at any given legume percentage being negative. DEA was higher in plots with legumes, decreased with increasing percentage of grasses, and increased with richness. No correlation was observed between DEA and denitrifier abundance. NEA increased with the abundance of ammonia oxidizing bacteria. The effect of richness on NEA was entirely due to the build-up of nitrifying organisms, while legume effect was partly linked to modified ammonium availability and nitrifier abundance. Richness effect on DEA was entirely due to changes in soil moisture, while the effects of legumes and grasses were partly due to modified nitrate availability, which influenced the specific activity of denitrifiers. These results suggest that plant diversity-induced changes in microbial specific activity are important for facultative activities such as denitrification

  9. Combined Molecular and Conventional Analyses of Nitrifying Bacterium Diversity in Activated Sludge: Nitrosococcus mobilis and Nitrospira-Like Bacteria as Dominant Populations

    OpenAIRE

    Juretschko, Stefan; Timmermann, Gabriele; Schmid, Markus; Schleifer, Karl-Heinz; Pommerening-Röser, Andreas; Koops, Hans-Peter; WAGNER, Michael

    1998-01-01

    The ammonia-oxidizing and nitrite-oxidizing bacterial populations occurring in the nitrifying activated sludge of an industrial wastewater treatment plant receiving sewage with high ammonia concentrations were studied by use of a polyphasic approach. In situ hybridization with a set of hierarchical 16S rRNA-targeted probes for ammonia-oxidizing bacteria revealed the dominance of Nitrosococcus mobilis-like bacteria. The phylogenetic affiliation suggested by fluorescent in situ hybridization (F...

  10. Reconstruction of liver organoid using a bioreactor

    Institute of Scientific and Technical Information of China (English)

    Masaya Saito; Tomokazu Matsuura; Takahiro Masaki; Haruka Maehashi; Keiko Shimizu; Yoshiaki Hataba; Tohru Iwahori; Tetsuro Suzuki; Filip Braet

    2006-01-01

    AIM: To develop the effective technology for reconstruction of a liver organ in vitro using a bio-artificial liver.METHODS: We previously reported that a radial-flow bioreactor (RFB) could provide a three-dimensional highdensity culture system. We presently reconstructed the liver organoid using a functional human hepatocellular carcinoma cell line (FLC-5) as hepatocytes together with mouse immortalized sinusoidal endothelial cell (SEC) line M1 and mouse immortalized hepatic stellate cell (HSC) line A7 as non parenchymal cells in the RFB. Two x 107 FLC-5 cells were incubated in the RFB. After 5 d, 2 x 107 A7 cells were added in a similar manner followed by another addition of 107 M1 cells 5 d later. After three days of perfusion, some cellulose beads with the adherent cells were harvested. The last incubation period included perfusion with 200 nmol/L swinholide A for 2 h and then the remaining cellulose beads along with adherent cells were harvested from the RFB. The cell morphology was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). To assess hepatocyte function, we compared mRNA expression for urea cycle enzymes as well as albumin synthesis by FLC-5 in monolayer cultures compared to those of single-type cultures and cocultures in the RFB.RESULTS: By transmission electron microscopy, FLC-5,M1, and A7 were arranged in relation to the perfusion side in a liver-like organization. Structures resembling bile canaliculi were seen between FCL-5 cells. Scanning electron microscopy demonstrated fenestrae on SEC surfaces. The number of vesiculo-vacuolar organelles (WO) and fenestrae increased when we introduced the actin-binding agent swinholide-A in the RFB for 2h. With respect to liver function, urea was found in the medium,and expression of mRNAs encoding arginosuccinate synthetase and arginase increased when the three cell types were cocultured in the RFB. However, albumin synthesis decreased.CONCLUSION: Co-culture in the RFB

  11. Biological hydrogen production using a membrane bioreactor.

    Science.gov (United States)

    Oh, Sang-Eun; Iyer, Prabha; Bruns, Mary Ann; Logan, Bruce E

    2004-07-01

    A cross-flow membrane was coupled to a chemostat to create an anaerobic membrane bioreactor (MBR) for biological hydrogen production. The reactor was fed glucose (10,000 mg/L) and inoculated with a soil inoculum heat-treated to kill non-spore-forming methanogens. Hydrogen gas was consistently produced at a concentration of 57-60% in the headspace under all conditions. When operated in chemostat mode (no flow through the membrane) at a hydraulic retention time (HRT) of 3.3 h, 90% of the glucose was removed, producing 2200 mg/L of cells and 500 mL/h of biogas. When operated in MBR mode, the solids retention time (SRT) was increased to SRT = 12 h producing a solids concentration in the reactor of 5800 mg/L. This SRT increased the overall glucose utilization (98%), the biogas production rate (640 mL/h), and the conversion efficiency of glucose-to-hydrogen from 22% (no MBR) to 25% (based on a maximum of 4 mol-H(2)/mol-glucose). When the SRT was increased from 5 h to 48 h, glucose utilization (99%) and biomass concentrations (8,800 +/- 600 mg/L) both increased. However, the biogas production decreased (310 +/- 40 mL/h) and the glucose-to-hydrogen conversion efficiency decreased from 37 +/- 4% to 18 +/- 3%. Sustained permeate flows through the membrane were in the range of 57 to 60 L/m(2) h for three different membrane pore sizes (0.3, 0.5, and 0.8 microm). Most (93.7% to 99.3%) of the membrane resistance was due to internal fouling and the reversible cake resistance, and not the membrane itself. Regular backpulsing was essential for maintaining permeate flux through the membrane. Analysis of DNA sequences using ribosomal intergenic spacer analysis indicated bacteria were most closely related to members of Clostridiaceae and Flexibacteraceae, including Clostridium acidisoli CAC237756 (97%), Linmingia china AF481148 (97%), and Cytophaga sp. MDA2507 AF238333 (99%). No PCR amplification of 16s rRNA genes was obtained when archaea-specific primers were used.

  12. Effect of Nitrified Leachate Recirculation on In-situ Denitrification, Methanogenesis and Stabilization of Landfill%硝化渗滤液回灌对填埋垃圾反硝化、产甲烷及稳定化的影响

    Institute of Scientific and Technical Information of China (English)

    杨暖; 何晓红; 李大平; 胡吉军; 王晓梅; 陶勇

    2011-01-01

    垃圾填埋场是重要的甲烷释放源,其有效管理是减缓温室效应的重要环节.通过硝化渗滤液回灌模拟垃圾填埋柱,研究硝化渗滤液在新鲜垃圾和老龄垃圾填埋柱中的脱氮及对垃圾稳定化和产甲烷的影响.结果表明,回灌的硝化渗滤液在不同填埋龄垃圾柱中,均可实现总氧化态氮(Total oxidation nitroge,TON)完全还原.当回灌TON负荷分别达到14.19 g t-1(TS)d-1和10.45 g t-1(TS)d-1时,新、老垃圾柱中甲烷产生开始受到抑制.实验后期,回灌TON负荷增至38.78g t-1(TS)d-1和30.62 g t-1(TS)d-1时,新、老垃圾填埋柱产甲烷相对抑制率分别达54.10%和95.77%.同时,回灌反硝化对新、老垃圾柱中垃圾降解贡献率(Rd)分别达85%和93%,能有效促进垃圾稳定.%Landfill has been considered an important source of methane emission, so its effective management plays a key role in slowing down the pace of greenhouse effect.In this paper, nitrogen removal, methanogenesis and stabilization of municipal solid waste (MSW) were studied in two serie s of lab-scale MSW bioreactor landfill (BL) with fre sh and old refuse, respectively,where nitrified leachate was recirculated.The results indicated that total oxidation nitrogen (TON) of the nitrified leachate was completely reduced in the simulated BLs, and methanogenesis in the fresh and old BL would be inhabited when TON load was increased to 14.19 g t-1(TS) d-1 and 10.45 g t-1(TS) d-1, respectively.At the later period of operation, while TON loading from the nitrified leachate increased to 38.78 g t-1(TS) d-1 and 30.62 g t-1(TS) d-1, the relative inhibition rate of methanogenesis reached 54.10% and 95.77% in fresh and old BL, respectively.Meanwhile, it was be proved that in-situ denitrification could promote the decomposition of the MSW, in which the contribution of denitrification to MSW decomposition (Rd) would be 85% and 93%.Fig 5, Tab 1, Ref 30

  13. Nitrosomonas Nm143-like ammonia oxidizers and Nitrospira marina -like nitrite oxidizers dominate the nitrifier community in a marine aquaculture biofilm

    DEFF Research Database (Denmark)

    Foesel, Bärbel U.; Gieseke, Armin; Schwermer, Carsten;

    2008-01-01

    Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated with a re......Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated......A) confirmed the results. The most abundant ammonia-oxidizing bacteria (AOB) were members of the Nitrosomonas sp. Nm143-lineage (6.7% of the bacterial biovolume), followed by Nitrosomonas marina-like AOB (2.2% of the bacterial biovolume). Both were outnumbered by nitrite-oxidizing bacteria of the Nitrospira...... marina lineage (15.7% of the bacterial biovolume). Although more than eight other nitrifying populations were detected, including Crenarchaeota closely related to the ammonia-oxidizer ‘Nitrosopumilus maritimus’, their collective abundance was below 1% of the total biofilm volume; their contribution...

  14. 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.

  15. 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

  16. 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.

  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. BIOREACTOR ECONOMICS, SIZE AND TIME OF OPERATION (BEST) COMPUTER SIMULATOR FOR DESIGNING SULFATE-REDUCING BACTERIA FIELD BIOREACTORS

    Science.gov (United States)

    BEST (bioreactor economics, size and time of operation) is an Excel™ spreadsheet-based model that is used in conjunction with the public domain geochemical modeling software, PHREEQCI. The BEST model is used in the design process of sulfate-reducing bacteria (SRB) field bioreacto...

  19. Hepatocyte function within a stacked double sandwich culture plate cylindrical bioreactor for bioartificial liver system.

    Science.gov (United States)

    Xia, Lei; Arooz, Talha; Zhang, Shufang; Tuo, Xiaoye; Xiao, Guangfa; Susanto, Thomas Adi Kurnia; Sundararajan, Janani; Cheng, Tianming; Kang, Yuzhan; Poh, Hee Joo; Leo, Hwa Liang; Yu, Hanry

    2012-11-01

    Bioartificial liver (BAL) system is promising as an alternative treatment for liver failure. We have developed a bioreactor with stacked sandwich culture plates for the application of BAL. This bioreactor design addresses some of the persistent problems in flat-bed bioreactors through increasing cell packing capacity, eliminating dead flow, regulating shear stress, and facilitating the scalability of the bioreactor unit. The bioreactor contained a stack of twelve double-sandwich-culture plates, allowing 100 million hepatocytes to be housed in a single cylindrical bioreactor unit (7 cm of height and 5.5 cm of inner diameter). The serial flow perfusion through the bioreactor increased cell-fluid contact area for effective mass exchange. With the optimal perfusion flow rate, shear stress was minimized to achieve high and uniform cell viabilities across different plates in the bioreactor. Our results demonstrated that hepatocytes cultured in the bioreactor could re-establish cell polarity and maintain liver-specific functions (e.g. albumin and urea synthesis, phase I&II metabolism functions) for seven days. The single bioreactor unit can be readily scaled up to house adequate number of functional hepatocytes for BAL development.

  20. Influence of wastewater composition on nutrient removal behaviors in the new anaerobic-anoxic/nitrifying/induced crystallization process.

    Science.gov (United States)

    Shi, Jing; Lu, Xiwu; Yu, Ran; Gu, Qian; Zhou, Yi

    2014-01-01

    In this study, the new anaerobic-anoxic/nitrifying/induced crystallization (A2N-IC) system was compared with anaerobic-anoxic/nitrifying (A2N) process to investigate nutrient removal performance under different influent COD and ammonia concentrations. Ammonia and COD removal rates were very stable in both processes, which were maintained at 84.9% and 86.6% when the influent ammonia varied from 30 mg L(-1) to 45 mg L(-1) and COD ranged from 250 mg L(-1) to 300 mg L(-1). The effluent phosphorus always maintained below 0.2 mg L(-1) in A2N-IC, whereas in A2N the effluent phosphorus concentration was 0.4-1.7 mg L(-1), demonstrating that A2N-IC is suitable to apply in a broader influent COD and ammonia concentration range. Under higher influent COD (300 mg L(-1)) or lower ammonia conditions (30 mg L(-1)), the main function of chemical induced crystallization was to coordinate better nutrient ratio for anoxic phosphorus uptake, whereas under high phosphorus concentration, it was to reduce phosphorus loading for biological system. Under the similar influent wastewater compositions, phosphorus release amounts were always lower in A2N-IC. To clarify the decrease procedure of phosphorus release in the A2N-IC, the equilibrium between chemical phosphorus removal and biological phosphorus removal in A2N-IC was analyzed by mass balance equations. During the long-term experiment, some undesirable phenomena were observed: the declining nitrification in post-aerobic tank and calcium phosphorus precipitation in the anaerobic tank. The reasons were analyzed; furthermore, the corresponding improvements were proposed. Nitrification effect could be enhanced in the post-aerobic tank, therefore ammonia removal rate could be increased; and biologically induced phosphorus precipitation could be inhibited by controlling pH at the anaerobic stage, so the phosphorus release and recovery could be improved. PMID:24596502

  1. Control of nitratation in an oxygen-limited autotrophic nitrification/denitrification rotating biological contactor through disc immersion level variation.

    Science.gov (United States)

    Courtens, Emilie N P; Boon, Nico; De Clippeleir, Haydée; Berckmoes, Karla; Mosquera, Mariela; Seuntjens, Dries; Vlaeminck, Siegfried E

    2014-03-01

    With oxygen supply playing a crucial role in an oxygen-limited autotrophic nitrification/denitrification (OLAND) rotating biological contactor (RBC), its controlling factors were investigated in this study. Disc rotation speeds (1.8 and 3.6rpm) showed no influence on the process performance of a lab-scale RBC, although abiotic experiments showed a significant effect on the oxygenation capacity. Estimations of the biological oxygen uptake rate revealed that 85-89% of the oxygen was absorbed by the microorganisms during the air exposure of the discs. Indeed, increasing the disc immersion (50 to 75-80%) could significantly suppress undesired nitratation, on the short and long term. The presented results demonstrated that nitratation could be controlled by the immersion level and revealed that oxygen control in an OLAND RBC should be predominantly based on the atmospheric exposure percentage of the discs.

  2. 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

  3. 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 role of terrestrial carbon, were investigated by relating surface-water partial pressure of CO2 (PCO2), NCP, GPP, and CR to physicochemical conditions, chlorophyll a (Chl a) concentration, phytoplankton production, inventories of particulate (POC) and dissolved organic carbon (DOC) and vertical flux...... of POC. The planktonic community was net heterotrophic in the photic zone in September (NCP = −21 ± 45 mmol O2 m−2 d−1) and February (NCP = −17 mmol O2 m−2 d−1) but net autotrophic during a developing spring bloom in May (NCP = 129 ± 102 mmol O2 m−2 d−1). In September, higher temperatures, shorter day...

  4. Autotrophic denitrification performance and bacterial community at biocathodes of bioelectrochemical systems with either abiotic or biotic anodes.

    Science.gov (United States)

    Nguyen, Van Khanh; Hong, Sungsug; Park, Younghyun; Jo, Kyungmin; Lee, Taeho

    2015-02-01

    Two-chamber bioelectrochemical systems (BESs) have recently been developed for nitrate removal from nitrate-contaminated water. In this study, we compared the nitrate removal performance of biocathodes of BESs when using abiotic and biotic anodes. Acetate was used as electron donor in BESs with biotic anode, whereas a direct current power supply was used as energy source in BESs with abiotic anode. The nitrogen removal efficiency increased from 18.1% to 43.0% when the voltage supplied to the BES with abiotic anode increased from 0.7 V to 0.9 V, whereas no higher removal efficiency was obtained at a higher supplied voltage (1.1 V). The highest efficiency (78.0%) of autotrophic nitrogen removal was achieved when electron transfer from the biotic anode chamber of BESs was used. Unexpectedly, control of the cathode potential did not enhance nitrate removal in BESs with biotic anode. Special attention was paid to elucidate the differences of bacterial communities catalysing autotrophic denitrification in the biocathodes of BESs with abiotic and biotic anodes. Data from denaturing gradient gel electrophoresis and phylogenetic analysis suggested that denitrification in BESs with abiotic anode could be attributed to Nitratireductor sp., Shinella sp., and Dyella sp., whereas the dominant bacterial denitrifiers in BESs with biotic anode were found to be Pseudomonas sp., Curtobacterium sp., and Aeromonas sp. These results implied that biocathodes of BESs with biotic anode are more efficient than those of BESs with abiotic anode for nitrate removal from nitrate-contaminated water in practical applications.

  5. Temporal variations in metabolic and autotrophic indices for Acropora digitifera and Acropora spicifera--implications for monitoring projects.

    Directory of Open Access Journals (Sweden)

    Saskia Hinrichs

    Full Text Available Coral health indices are important components of the management assessments of coral reefs, providing insight into local variation in reef condition, as well as tools for comparisons between reefs and across various time scales. Understanding how such health indices vary in space and time is critical to their successful implementation as management tools. Here we compare autotrophic and heterotrophic coral health indices, examining specifically the temporal variation driven by the local environmental variation, at three scales (diel, daily and seasonal. We compared metabolic indices (RNA/DNA ratio, protein concentration and autotrophic indices (Chlorophyll a (Chl a, zooxanthellae density, effective quantum yield (yield and relative electron transport rate (rETR for two dominant Acropora species, A. digitifera and A. spicifera at Ningaloo Reef (north-western Australia in August 2010 (austral winter and February 2011 (austral summer. Clear seasonal patterns were documented for metabolic indices, zooxanthellae density and rETR, while cyclic diel patterns only occurred for yield and rETR, and RNA/DNA ratio. Significant daily variation was observed for RNA/DNA ratio, Chl a concentration, yield and rETR. Results suggest that zooxanthellae density and protein concentrations are good long-term indicators of coral health whose variance is largely seasonal, while RNA/DNA ratio and rETR can be used for both long-term (seasonal and short-term (diel coral monitoring. Chl a can be used to describe changes between days and yield for both diel and daily variations. Correlations between health indices and light history showed that short-term changes in irradiance had the strongest impact on all health indices except zooxanthellae density for A. digitifera; for A. spicifera no correlation was observed at all. However, cumulative irradiance over the several days before sampling showed significant correlations with most health indices suggesting that a time

  6. Lake acidification and oxygen depletion may synergistically enhance nitrous oxide (N2O) production by nitrifier denitrification in a subalpine lake

    Science.gov (United States)

    Frame, C. H.; Goepfert, T. J.; Rollog, M.; Lehmann, M. F.

    2013-12-01

    Ammonia-oxidizing microorganisms are an important source of the greenhouse gas nitrous oxide (N2O). They produce N2O through two mechanisms: by the decomposition of an intermediate in the ammonia (NH3) oxidation reaction, and by nitrifier denitrification, which is the enzymatic reduction of nitrite (NO2-). We investigated the impact of water pH and oxygen (O2) concentrations on rates of N2O production by these two mechanisms in the water column of Lake Lugano, a subalpine lake between Switzerland and Italy. Acidification of natural waters is known to reduce the rate of ammonia oxidation by forcing the equilibrium NH4+ ←→ NH3 + H+ away from NH3, the form that is preferentially taken up by ammonia oxidizers. In turn, this reduces the rate of N2O production by decomposition of the reaction intermediate during ammonia oxidation. However, using 15NH4+ and 15NO2- tracer additions during lake water incubations, we showed that reducing the pH from in situ values of 7.5 to 8 down to 6 to 7 actually increased the rate of N2O production by nitrifier denitrification. Hypoxia is thought to enhance N2O production by nitrifier denitrification. We did not observe nitrifier denitrification in incubations that were fully oxic (partial pressure of O2 = 20.9%) or had reduced O2 (partial pressure = 12%). However, when the incubation pH was lowered and the O2 reduced to 12%, N2O production by nitrifier denitrification was much greater than it was in incubations where only the pH was reduced or only the O2 concentration was reduced. Water for these experiments was drawn from depths just below the epilimnion of the monomictic south basin of Lugano, an environment whose pH, O2, and nutrient concentrations fluctuate throughout the water column on a seasonal basis and change in the shallower depths on a daily basis. We discuss the implications of these changes for the flux of shallow N2O into the atmosphere and a possible mechanism that explains the synergistic influence of O2 and pH on

  7. The Research of Treatment of Aquaculture Water by Using Nitrifying Bacteria%硝化细菌对养殖水体处理技术的研究

    Institute of Scientific and Technical Information of China (English)

    姚秀清; 张全; 王庆庆

    2011-01-01

    以自行富集培养的硝化细菌为研究对象,分别考察了其对模拟养殖水体和人工湖水中氨氮(NH4+-N)、亚硝酸氮(NO2--N)的降解效果.结果表明,自然状态养殖水体(未投加硝化细菌)中氨氮积累的浓度较小,且变化不大;而亚硝酸氮的浓度则从0mg·L-1增加到1.483mg·L-1,且增长速度较快.投加硝化细菌20mL后,亚硝酸氮浓度降至0.0408mg·L-1,降解率为97.2%.硝化细菌投加量对亚硝酸氮的降解有一定的影响,当投菌量为0.0067g干菌·L-1时,模拟养殖水体和人工湖水中积累的亚硝酸氮的浓度略有上升,但升幅较小,最终都能维持在0.1mg·L-1以下,属于安全浓度.%In this paper, the nitrifying bacteria which had been well enriched and cultured were used to degrade ammonia-nitrogen (NH4+-N) and nitrite-nitrogen (NO2--N) in simulated aquaculture water and artificial lake water. The experimental results showed that the concentration of ammonia-nitrogen accumulated in the natural state of aquaculture water(without addition of nitrifying bacteria) was very low with little change,while the concentration of nitrite-nitrogen increased lastly from 0 mg·L-1 to 1. 483 mg·L-1. After adding 20 mL nitrifying bacteria, the concentration of ammonia-nitrogen reduced to 0. 0408 mgL-1 , and the removal rate reached 97.2%. The dosage of nitrifying bacteria had a certain impact on the degradation of nitrite-nitrogen. When the dosage of nitrifying bacteria was 0. 0067 g bacteria (dry weight) per liter, the concentration of nitrite-nitrogen both in aquaculture water and artificial lake water increased slightly in the first days, and then decreased and ultimately could be maintained under 0.1 mg·L-1 , which was safety.

  8. Development of a bioreactor based on magnetically stabilized fluidized bed for bioartificial liver.

    Science.gov (United States)

    Deng, Fei; Chen, Li; Zhang, Ying; Zhao, Shan; Wang, Yu; Li, Na; Li, Shen; Guo, Xin; Ma, Xiaojun

    2015-12-01

    Bioartificial liver (BAL) based on microcapsules has been proposed as a potential treatment for acute liver failure. The bioreactors used in such BAL are usually expected to achieve sufficient flow rate and minimized void volume for effective application. Due to the superiorities in bed pressure drop and operation velocity, magnetically stabilized fluidized beds (MSFBs) show the potential to serve as ideal microcapsule-based bioreactors. In the present study, we attempted to develop a microcapsule-based MSFB bioreactor for bioartificial liver device. Compared to conventional-fluidized bed bioreactors, the bioreactor presented here increased perfusion velocity and decreased void volume significantly. Meanwhile, the mechanical stability as well as the immunoisolation property of magnetite microcapsules were well maintained during the fluidization. Besides, the magnetite microcapsules were found no toxicity to cell survival. Therefore, our study might provide a novel approach for the design of microcapsule-based bioartificial liver bioreactors.

  9. Production of bacterial cellulose membranes in a modified airlift bioreactor by Gluconacetobacter xylinus.

    Science.gov (United States)

    Wu, Sheng-Chi; Li, Meng-Hsun

    2015-10-01

    In this study, a novel bioreactor for producing bacterial cellulose (BC) is proposed. Traditional BC production uses static culture conditions and produces a gelatinous membrane. The potential for using various types of bioreactor, including a stirred tank, conventional airlift, and modified airlift with a rectangular wire-mesh draft tube, in large-scale production has been investigated. The BC obtained from these bioreactors is fibrous or in pellet form. Our proposed airlift bioreactor produces a membrane-type BC from Gluconacetobacter xylinus, the water-holding capacity of which is greater than that of cellulose types produced using static cultivation methods. The Young's modulus of the product can be manipulated by varying the number of net plates in the modified airlift bioreactor. The BC membrane produced using the proposed bioreactor exhibits potential for practical application.

  10. Production of bacterial cellulose membranes in a modified airlift bioreactor by Gluconacetobacter xylinus.

    Science.gov (United States)

    Wu, Sheng-Chi; Li, Meng-Hsun

    2015-10-01

    In this study, a novel bioreactor for producing bacterial cellulose (BC) is proposed. Traditional BC production uses static culture conditions and produces a gelatinous membrane. The potential for using various types of bioreactor, including a stirred tank, conventional airlift, and modified airlift with a rectangular wire-mesh draft tube, in large-scale production has been investigated. The BC obtained from these bioreactors is fibrous or in pellet form. Our proposed airlift bioreactor produces a membrane-type BC from Gluconacetobacter xylinus, the water-holding capacity of which is greater than that of cellulose types produced using static cultivation methods. The Young's modulus of the product can be manipulated by varying the number of net plates in the modified airlift bioreactor. The BC membrane produced using the proposed bioreactor exhibits potential for practical application. PMID:25823854

  11. The Short-term Effects of Temperature and Free Ammonia on Ammonium Oxidization in Granular and Floccular Nitrifying System

    Institute of Scientific and Technical Information of China (English)

    吴蕾; 彭永臻; 马勇; 刘旭; 李凌云; 王淑莹

    2012-01-01

    The short-term effects of temperature and free ammonia (FA) on ammonium oxidization were investigated in this study by operating several batch tests with two different partial nitrification aggregates, formed as either granules or flocs. The results showed that the rate of ammonium oxidation in both cultures increased significantly as temperature increased from 10 to 30 °C. The specific ammonium oxidation rate with the granules was 2-3 times higher than that with flocs at the same temperature. Nitrification at various FA concentrations and temperatures combination exhibited obvious inhibition in ammonium oxidation rate when FA was 90 mg·L 1 and tempera- ture dropped to 10 °C in the two systems. However, the increase in substrate oxidation rate of ammonia at 30 °C was observed. The results suggested that higher reaction temperature was helpful to reduce the toxicity of FA. Granules appeared to be more tolerant to FA attributed to the much fraction of ammonia oxidizing bacteria (AOB) and higher resistance to the transfer of ammonia into the bacterial aggregates, whereas in the floc system, the bacteria distributed throughout the entire aggregate. These results may contribute to the applicability of the nitrifying granules in wastewater treatment operated at high ammonium concentration.

  12. Novel nitrifiers and comammox in a full-scale hybrid biofilm and activated sludge reactor revealed by metagenomic approach.

    Science.gov (United States)

    Chao, Yuanqing; Mao, Yanping; Yu, Ke; Zhang, Tong

    2016-09-01

    Biofilms are widely used in wastewater treatment for their particular enhancement of nitrogen removal and other significant advantages. In this study, the diversity and potential functions of nitrogen removal bacteria in suspended activated sludge (AS) and biofilm of a full-scale hybrid reactor were uncovered by metagenomes (∼34 Gb), coupled with PCR-based 454 reads (>33 K reads). The results indicated that the diversity and abundance of nitrifiers and denitrifiers in biofilm did not surpass that in AS, while more nitrification and denitrification genes were indeed found in biofilm than AS, suggesting that the increased nitrogen removal ability by applying biofilm might be attributed to the enhancement of removal efficiency, rather than the biomass accumulation of nitrogen removal bacteria. The gene annotation and phylogenetic analysis results revealed that AS and biofilm samples consisted of 6.0 % and 9.4 % of novel functional genes for nitrogen removal and 18 % and 30 % of new Nitrospira species for nitrite-oxidizing bacteria, respectively. Moreover, the identification of Nitrospira-like amoA genes provided metagenomic evidence for the presence of complete ammonia oxidizer (comammox) with the functional potential to perform the complete oxidation of ammonia to nitrate. These findings have significant implications in expanding our knowledge of the biological nitrogen transformations in wastewater treatment. PMID:27287850

  13. Application of a novel functional gene microarray to probe the functional ecology of ammonia oxidation in nitrifying activated sludge.

    Directory of Open Access Journals (Sweden)

    Michael D Short

    Full Text Available We report on the first study trialling a newly-developed, functional gene microarray (FGA for characterising bacterial and archaeal ammonia oxidisers in activated sludge. Mixed liquor (ML and media biofilm samples from a full-scale integrated fixed-film activated sludge (IFAS plant were analysed with the FGA to profile the diversity and relative abundance of ammonia-oxidising archaea and bacteria (AOA and AOB respectively. FGA analyses of AOA and AOB communities revealed ubiquitous distribution of AOA across all samples - an important finding for these newly-discovered and poorly characterised organisms. Results also revealed striking differences in the functional ecology of attached versus suspended communities within the IFAS reactor. Quantitative assessment of AOB and AOA functional gene abundance revealed a dominance of AOB in the ML and approximately equal distribution of AOA and AOB in the media-attached biofilm. Subsequent correlations of functional gene abundance data with key water quality parameters suggested an important functional role for media-attached AOB in particular for IFAS reactor nitrification performance and indicate possible functional redundancy in some IFAS ammonia oxidiser communities. Results from this investigation demonstrate the capacity of the FGA to resolve subtle ecological shifts in key microbial communities in nitrifying activated sludge and indicate its value as a tool for better understanding the linkages between the ecology and performance of these engineered systems.

  14. Layer-by-layer carbon nanotube bio-templates for in situ monitoring of the metabolic activity of nitrifying bacteria

    Science.gov (United States)

    Loh, Kenneth J.; Guest, Jeremy S.; Ho, Genevieve; Lynch, Jerome P.; Love, Nancy G.

    2009-03-01

    Despite the wide variety of effective disinfection and wastewater treatment techniques for removing organic and inorganic wastes, pollutants such as nitrogen remain in wastewater effluents. If left untreated, these nitrogenous wastes can adversely impact the environment by promoting the overgrowth of aquatic plants, depleting dissolved oxygen, and causing eutrophication. Although nitrification/denitrification processes are employed during advanced wastewater treatment, effective and efficient operation of these facilities require information of the pH, dissolved oxygen content, among many other parameters, of the wastewater effluent. In this preliminary study, a biocompatible CNT-based nanocomposite is proposed and validated for monitoring the biological metabolic activity of nitrifying bacteria in wastewater effluent environments (i.e., to monitor the nitrification process). Using carbon nanotubes and a pH-sensitive conductive polymer (i.e., poly(aniline) emeraldine base), a layer-by-layer fabrication technique is employed to fabricate a novel thin film pH sensor that changes its electrical properties in response to variations in ambient pH environments. Laboratory studies are conducted to evaluate the proposed nanocomposite's biocompatibility with wastewater effluent environments and its pH sensing performance.

  15. Anaerobic ammonium oxidation in a bioreactor treating slaughterhouse wastewater

    Directory of Open Access Journals (Sweden)

    V. Reginatto

    2005-12-01

    Full Text Available Ammonium oxidation was thought to be an exclusively aerobic process; however, as recently described in the literature, it is also possible under anaerobic conditions and this process was named ANAMMOX. This work describes the operation of a system consisting of a denitrifying reactor coupled to a nitrifying reactor used for removal of nitrogen from slaughterhouse wastewater. During operation of the denitrifying reactor an average nitrogen ammonium removal rate of 50 mg/Ld was observed. This biomass was used to seed a second reactor, operated in repeated fed batch mode, fed with synthetic medium specific to the growth of bacteria responsible for the ANAMMOX process. The nitrogen loading rate varied between 33 and 67 mgN/Ld and average nitrogen removal was 95% and 40%, respectively. Results of fluorescence in situ hybridization (FISH confirmed the presence of anammox-like microorganisms in the enriched biomass.

  16. Characterization of organic membrane foulants in a forward osmosis membrane bioreactor treating anaerobic membrane bioreactor effluent.

    Science.gov (United States)

    Ding, Yi; Tian, Yu; Li, Zhipeng; Liu, Feng; You, Hong

    2014-09-01

    In this study, two aerobic forward osmosis (FO) membrane bioreactors (MBR) were utilized to treat the effluent of mesophilic (35°C) and atmospheric (25°C) anaerobic MBRs, respectively. The results showed that the FO membrane process could significantly improve the removal efficiencies of N and P. Meanwhile, the flux decline of the FOMBR treating effluent of mesophilic AnMBR (M-FOMBR) was higher than that treating effluent of atmospheric AnMBR (P-FOMBR). The organic membrane foulants in the two FOMBRs were analyzed to understand the membrane fouling behavior in FO processes. It was found that the slightly increased accumulation of protein-like substances into external foulants did not cause faster flux decline in P-FOMBR than that in M-FOMBR. However, the quantity of organic matter tended to deposit or adsorb into FO membrane pores in P-FOMBR was less than that in M-FOMBR, which was accordance with the tendency of membrane fouling indicated by flux decline.

  17. Characterization of organic membrane foulants in a forward osmosis membrane bioreactor treating anaerobic membrane bioreactor effluent.

    Science.gov (United States)

    Ding, Yi; Tian, Yu; Li, Zhipeng; Liu, Feng; You, Hong

    2014-09-01

    In this study, two aerobic forward osmosis (FO) membrane bioreactors (MBR) were utilized to treat the effluent of mesophilic (35°C) and atmospheric (25°C) anaerobic MBRs, respectively. The results showed that the FO membrane process could significantly improve the removal efficiencies of N and P. Meanwhile, the flux decline of the FOMBR treating effluent of mesophilic AnMBR (M-FOMBR) was higher than that treating effluent of atmospheric AnMBR (P-FOMBR). The organic membrane foulants in the two FOMBRs were analyzed to understand the membrane fouling behavior in FO processes. It was found that the slightly increased accumulation of protein-like substances into external foulants did not cause faster flux decline in P-FOMBR than that in M-FOMBR. However, the quantity of organic matter tended to deposit or adsorb into FO membrane pores in P-FOMBR was less than that in M-FOMBR, which was accordance with the tendency of membrane fouling indicated by flux decline. PMID:24976492

  18. Biodegradation of Trichloroethylene in Continuous-Recycle Expanded-Bed Bioreactors

    OpenAIRE

    Phelps, T. J.; Niedzielski, J. J.; Schram, R M; Herbes, S. E.; White, D. C.

    1990-01-01

    Experimental bioreactors operated as recirculated closed systems were inoculated with bacterial cultures that utilized methane, propane, and tryptone-yeast extract as aerobic carbon and energy sources and degraded trichloroethylene (TCE). Up to 95% removal of TCE was observed after 5 days of incubation. Uninoculated bioreactors inhibited with 0.5% Formalin and 0.2% sodium azide retained greater than 95% of their TCE after 20 days. Each bioreactor consisted of an expanded-bed column through wh...

  19. Fluidized-bed bioreactor system for the microbial solubilization of coal

    Science.gov (United States)

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor. 2 figs.

  20. Fixed-bed bioreactor system for the microbial solubilization of coal

    Science.gov (United States)

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fixed-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fixed-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the large scale production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fixed-bed bioreactor. 1 fig., 1 tab.