Дисертації з теми "Fixation CO2"
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1
Paoli, George Carl. "Organization and regulation of the Rhodobacter capsulatus CO2 fixation genes /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487943610782543.
2
Castro, Gómez Fernando Simón. "Theoretical studies on transition metal catalyzed carbon dioxide fixation." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/403368.
Анотація:
S’han dut a terme estudis teòrics amb la finalitat d’avaluar mecanismes de reacció per a processos de fixació de CO2, catalitzats per complexos de metalls de transició. D’aquesta forma, s’han descrit detalladament els passos del mecanisme de reacció (reaccions d’opertura d’anell, inserció de CO2 i tancament de l’anell) per la formació de carbonats cíclics a partir de CO2 i diferents epòxids, sota l’acció catalítica de complexos de Zn(salen), conjuntament amb Nbu4X (X = I, Br). Les energies d’activació calculades DFT calculationsmitjançant DFT són qualitatives, seguint la línea dels resultats experimentals. Per altra banda, es va considerar un catalitzador d’alumini realment actiu per estudiar aquesta reacció però des d’un punt de vista quantitatiu. D’aquesta forma, es va examinar l’activitat del sistema catalític mitjançant el càlcul teòric de les freqüències de repetició (TOFs). Els resultats obtinguts es varen trobar en el mateix ordre de magnitud que en el cas dels experiments. L’últim mecanimse estudiat involucra la eracció de copolimerització entre CO2 i òxid de ciclohexè, catalitzat per un sistema binari format per l’esmentat complex d’alumini i NBu4I. Es van suposar tres possibles rutes per descriure la reacció depenent del nombre de catalitzadors involucrats en la reacció de propagació. Els resultats sugereixen que la copolimerització alternada és més favorable respecte la formació de carbonat cíclic. A més dels estudis anteriors, es van utilitzar mètodes d’espectrometria de masses de mobilitat d’ions (IM-MS) per a proporcionar informació estructural sobre una sèrie de complexos de metalls de transició involucrats en catàlisi homogènia. Es varen determinar les seccions eficaces de col•lisió (CCS) teòriques i es van ser comparades amb les resultants dels experiments de IM-MS. El resultat obtingut concordava perfectament entre ambdues metodologies.Se han llevado a cabo estudios teóricos con el fin de evaluar mecanismos de reacción para procesos de fijación de CO2 catalizados por complejos de metales de transición. De este modo, se describieron detalladamente los pasos del mecanismo de reacción (reacciones de apertura de anillo, de inserción de CO2 y de cierre de anillo) para la formación catalítica de carbonatos cíclicos a partir de CO2 y diferentes epóxidos, basada en complejos de Zn(salen), conjuntamente con NBu4X (X = I, Br). Se encontró que las energías de activación DFT calculadas están de manera cualitativa en línea con los resultados experimentales. Por otra parte, se consideró un catalizador de aluminio altamente activo para estudiar la misma reacción, pero desde un punto de vista cuantitativo. Así pues, se examinó la actividad del sistema catalizador mediante el cálculo teórico de las frecuencias de repetición (TOFs). Estas últimas resultaron en el mismo orden de magnitud que los experimentos. El último de los mecanismos estudiados aquí involucra la reacción de copolimerización entre CO2 y óxido de ciclohexeno catalizada por el sistema binario compuesto por dicho complejo de aluminio y NBu4I. Se encontraron tres posibles rutas para describir la reacción dependiendo el número de catalizadores involucrados en la reacción de propagación. Los resultados sugieren que la copolimerización alternada es más favorable con respecto a la formación del carbonato cíclico. Además de los estudios anteriores, se usaron métodos de espectrometría de masas de movilidad iónica (IM-MS) para proporcionar información estructural sobre una serie de complejos de metales de transición involucrados en catálisis homogénea. Se determinaron las secciones eficaces de colisión (CCS) teóricas y se compararon con las resultantes de los experimentos IM-MS. Se encontró un excelente acuerdo entre el resultado de ambas metodologías.
Theoretical studies have been conducted in order to evaluate reaction mechanisms for CO2 fixation processes catalyzed by transition metal complexes. Thus, detailed mechanistic steps (ring-opening, CO2 insertion and ring-closing reactions) were described for the catalytic formation of cyclic carbonates from CO2 and a series of epoxides based on Zn(salen) complexes, in conjunction with NBu4X(X=I, Br). The computed DFT activation energies were found to be qualitatively in line with the experimental findings. Moreover, a highly active Al catalyst (derived from amino triphenolate ligands) was considered to study the same reaction, but from a quantitative point of view. In light of this, the activity of this catalyst system was examined by means of the theoretical calculation of frequencies (TOFs). The latter resulted in the same order of magnitude as the experiments. The last mechanism studied here comprises the copolymerization reaction between CO2 and cyclohexene oxide mediated by the binary system composed of the aforementioned Al complex species and NBu4I. Three possible pathways were found to describe the reaction depending on the number of Al complexes involved in the propagation step. Results suggest that the alternating copolymerization should be the most favorable pathway over the formation of the five-membered cyclic carbonate product. In addition to the above studies, methods of ion mobility mass spectrometry (IM-MS) have been employed to provide structural information on a series of transition metal complexes involved in homogeneous catalysis. Theoretical collision cross sections (CCSs) were determined and compared with those resulting from IM-MS experiments. The outcome from both methodologies yielded excellent agreement.
3
Spona-Friedl, Marina [Verfasser]. "Substrate dependent heterotrophic CO2-fixation as indicator for metabolic phenotypes / Marina Spona-Friedl." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1219903590/34.
4
Cozzolino, Mariachiara. "CO2 fixation in cyclic carbonates and polycarbonates by salen-like based metal complexes." Doctoral thesis, Universita degli studi di Salerno, 2019. http://elea.unisa.it:8080/xmlui/handle/10556/4254.
Анотація:
2017 - 2018At the current rate of consumption of petroleum resources, they are predicted to be exhausted within the next century. For this reason, the development of new chemical processes using biorenewable resources is attracting an increasing interest... [edited by Author]
XXXI ciclo
5
Preiner, Martina [Verfasser], William [Gutachter] Martin, and Michael [Gutachter] Schmitt. "The abiotic pattern of biotic CO2 fixation / Martina Preiner ; Gutachter: William Martin, Michael Schmitt." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2020. http://d-nb.info/1206414278/34.
6
Yoshida, Shosuke. "Engineering of a Type III Rubisco from a Hyperthermophilic Archaeon Aimed to Enhance Catalytic Performance at Ambient Temperatures." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/57249.
Анотація:
Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第13793号
工博第2897号
新制||工||1428(附属図書館)
26009
UT51-2008-C709
京都大学大学院工学研究科合成・生物化学専攻
(主査)教授 今中 忠行, 教授 青山 安宏, 教授 濵地 格
学位規則第4条第1項該当
7
Kirstetter, Anne-Sophie. "Etude de la fixation du carbone inorganique chez la levure pour la production industrielle de molécules d’intérêt." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC015/document.
Анотація:
Ces dernières années ont vu un grand développement des biotechnologies blanches et de l'ingénierie métabolique avec l'objectif de remplacer les procédés de synthèse de molécules d’intérêt de l’industrie chimique classique par des voies de synthèse biologique. Dans ce contexte, les réactions anaplérotiques, qui produisent les acides dicarboxyliques, sont particulièrement intéressantes puisqu'au delà de la production de ces molécules d’intérêt elles permettent une fixation nette de carbone, réduisant ainsi l’impact environnemental des procédés. Ce travail de thèse a donc porté sur l'élaboration d'une stratégie d'ingénierie métabolique faisant appel à des réactions de fixation de carbone inorganique chez la levure pour la production d'acide malique, une molécule plateforme ayant de nombreuses applications industrielles. La levure Saccharomyces cerevisiae a été choisie comme hôte pour sa commodité d’utilisation dans les procédés industriels et ses nombreux outils génétiques. L'approche développée repose sur la mise en place d'une voie de production d'acide malique par surexpression de la phosphonéolpyruvate carboxylase d'Escherichia coli (PEPC), de la malate déshydrogénase peroxysomale de S. cerevisiae relocalisée dans le cytosol (MDH) et du transporteur d'acides dicarboxyliques de Schizosaccharomyces pombe. La souche de levure recombinante obtenue a été caractérisée lors d'essais en fioles, en présence notamment de carbonate de calcium pour assurer un apport de carbone inorganique. Ces essais ont permis de mettre en évidence un effet stimulant de l'apport de carbone inorganique sur la production de malate et d'obtenir des concentrations de malate de l'ordre de 2,5 g/L à partir de 50 g/L de glucose, pour un rendement maximal de 0,046 gramme de malate par gramme de glucose. Des essais en bioréacteur de 5 L en présence d'air ou d'air enrichi à 5% de CO2 ont montré un effet positif de l'apport de carbone inorganique sous forme de dioxyde de carbone sur la production de malate. La concentration maximale de malate obtenue est de 1,46 g/L à partir de 50 g/L de glucose, soit un rendement de 0,029 gramme de malate par gramme de glucose. Des souches intermédiaires exprimant la PEPC et la MDH obtenues pour la production de malate ont également été caractérisées pour la production d'éthanol, car elles semblaient présenter une augmentation du rendement de production d'éthanol par effet transhydrogénase par rapport à la souche sauvage. Les essais n'ont cependant pas permis de confirmer cette augmentation de rendementWhite biotechnologies have been developing quickly during the last decades, aiming at replacing chemical syntheses by biological processes for the industrial production of target compounds. In this context, the implementation of anaplerotic reactions in the metabolism is of great interest, since those reactions allow both production of dicarboxylic acids and direct fixation of inorganic carbon. This work is about the development of a metabolic engineering strategy using inorganic carbon fixation reactions to produce malic acid, a compound with various industrial applications. The yeast Saccharomyces cerevisiae was chosen as a host for its convenient use in industrial processes and the availability of genetic tools. The approach developed to produce malic acid is based on the overexpression of Escherichia coli phosphoenolpyruvate carboxylase (PEPC), S. cerevisiae peroxysomale malate dehydrogenase relocated in the cytosol (MDH) and Schizosaccharomyces pombe dicarboxylic acid carrier. A recombinant yeast strain expressing those three genes was obtained and characterised in shake-flasks experiments, involving more specifically calcium carbonate as an inorganic carbon source. Those experiments showed an enhancement of the malate production in the presence of calcium carbonate and allowed to obtain a concentration of 2.5 g/L from 50 g/L glucose, for a maximal yield of 0.046 gram malate per gram glucose. Fermentation experiments were performed in a 5 L bioreactor in the presence of air or 5% CO2 enriched air; they confirmed the positive effect of inorganic carbon addition as CO2 on malate production. A malate concentration of 1.46 g/L from 50 g/L glucose was obtained, giving a yield of 0.029 gram malate per gram glucose. Intermediate recombinant strains expressing PEPC and MDH were also characterised, for ethanol production, as they seemed to give increased ethanol yields, probably due to a transhydrogenase effect. Shake flasks and bioreactors experiments did unfortunately not confirm the yield improvement
8
Joshi, Gauri Suresh. "Regulation of CO2 fixation in Rhodopseudomonas palustris mediated by a unique two-component regulatory system." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1273605616.
9
Garcia, Susana. "Experimental and simulation studies of iron oxides for geochemical fixation of CO2-SO2 gas mixtures." Thesis, University of Nottingham, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523076.
10
Carrillo, Camacho Martina [Verfasser], and Tobias J. [Akademischer Betreuer] Erb. "Implementation of CO2 fixation pathways into Methylorubrum extorquens AM1 / Martina Carrillo Camacho ; Betreuer: Tobias J. Erb." Marburg : Philipps-Universität Marburg, 2021. http://d-nb.info/1229619917/34.
11
Al, Ketife Ahmed Majeed Daife. "Modelling and Optimization of Combined Wastewater Treatment and CO2 Bio-fixation in a Batch Algal Photobioreactor." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59696.
Анотація:
The research focuses on investigation and optimization (using Box Behnken design) of the key parameters of CO2 gas concentration, light intensity, temperature, feedwater nutrient concentration, and wastewater origin (municipal primary and secondary, and petroleum industry) on photobioreactor algal growth parameters. A mathematical model is provided for predicting algal growth. Finally, the influence of light wavelength on algal growth is investigated. The outcomes can be used to inform design and operation of large-scale algal cultivation systems.
12
Abreu, Carlos Eduardo Aragón. "Physiological characteristics as analyzed by hormone profile, metabolic pathways and expression of specific induced genes of C3, C4 and CAM tropical crops propagated by Temporary Immersion Bioreactors (TIB)." Doctoral thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/9264.
Анотація:
Doutoramento em Engenharia Agronómica - Instituto Superior de AgronomiaPhysiology and biochemistry of in vitro plants can be complex and different when compared with conventional and well known plant ex vitro behavior. Metabolic reprogramming events that occur in a number of in vitro propagated plant species give rise to low ex vitro yields as a handicap for commercial application. Temporary Immersion Bioreactors (TIB) are a method to obtain plantlet morphology and physiology much alike that of in vivo grown plants. Three tropical crops were selected for their economic importance, but also because of their different photosynthetic characteristics, to compare C4 (sugarcane) and C3-CAM (pineapple) facultative photosynthetic pathways to the more common C3-type (plantain) photosynthesis. Experiments performed using plantain and sugarcane allowed to integrate the results obtained when monitoring the oxidative stress response in C3 and C4 metabolism. Pineapple plants propagated in TIB and evaluated during acclimatization under C3 and CAM inducing conditions were used to describe the facultative C3-CAM carbon metabolism and the influence of the environmental conditions on the switch from C3 to CAM. Studies based on the modulation of in vitro conditions which reproduce abiotic stress conditions can be used for understanding the influence of upcoming climate changes on the physiology of different species
FCT
13
Meakin, Nicholas G. "Metagenomic analyses of marine new production under elevated CO2 conditions." Thesis, University of Stirling, 2009. http://hdl.handle.net/1893/1555.
Анотація:
A mesocosm experiment was carried out in a Norwegian fjord near Bergen in May 2006, with the main objective being the study of the effects of increasing concentrations of atmospheric CO2 (and associated effects such as increased acidification) on blooms of natural marine coastal plankton. Three mesocosms were bubbled with CO2(g) to achieve a high (~700ppm) CO2 concentration (pH ~7.8) to simulate predicted future conditions as a result of rising atmospheric CO2 concentrations. Another three mesocosms were treated as controls and bubbled with ambient air to represent a near pre-industrial scenario (atmospheric CO2 concentration ~300ppm, surface seawater pH ~8.15). Blooms in the mesocosms were stimulated by the addition of nutrients at a near-Redfield ratio ([N:P] ≈ [16:1]), and scientific measurements and analyses were carried out over the course of the blooms for approximately one month. Of particular interest in this study were the autotrophic plankton. The diversity and activities of these microorganisms under the two treatments was therefore investigated. By designing and using new degenerate primers specifically targeting ‘Green-type’ (Form IA and IB), ‘Red-type’ (Form IC and ID) and Form II RuBisCO, analysis of primary producers was carried out using PCR and either gDNA or cDNA (mRNA) templates from key time points spanning the complete duration of the blooms throughout the mesocosm experiment. Over 1250 novel RuBisCO large subunit sequences have been fully annotated and deposited in the NCBI GenBank® database. These sequences revealed distinct changes in the diversity of primary producers both over the courses of the blooms and between treatments. Particularly striking was the effect of acidification on the community structure of the eukaryotic picoplankton, Prasinophytes. A clade of prasinophytes closely related to Micromonas pusilla showed a distinct preference for the high CO2 conditions; a laboratory-based experiment confirmed the high tolerance of Micromonas pusilla to lower pH. Conversely, a clade related to Bathycoccus prasinos was almost entirely excluded from the high CO2 treatments. Clades of form II RuBisCO-containing dinoflagellates were also abundant throughout the experiment in both treatments. The high similarity of some of these clades to the toxin-producing species Heterocapsa triquetra and Gonyaulax polyedra, and apparent high tolerance of some clades to high CO2 conditions, is perhaps cause for concern in a high CO2 world and demands further research. In parallel with the RubisCO work, new primers were designed that target the gene encoding the Fe protein of nitrogenase (NifH). 82 Bergen genomic nifH sequences have been annotated and submitted to GenBank®. These sequences include those from organisms related to Alpha, Beta, and Gammaproteobacteria, and Cluster II and Cluster III sequences that align most closely with anaerobic Bacteria, Gram positive, and/or sulphur-reducing Bacteria. The biggest surprise, however, was the apparent abundance and significance of a Rhodobacter sphaeroides-like microorganism throughout the duration of the experiment in both treatments. Whilst this clade was unsurprisingly absent in the RuBisCO cDNA libraries, all but two of 128 nifH cDNA clones analysed were identical to the gene from Rhodobacter sphaeroides. This shows that this clade was potentially fixing N2 throughout the entire experiment, even in the presence of combined N added to both sets of mesocosms at the start of the experiment. A group of Rhodobacter sphaeroides-like microorganisms present at Bergen may therefore have been an unexpected source of new N during the experiment and contributed to the maintenance of the mesocosm communities as nutrients became depleted. One organism dominated the autotrophic communities after the blooms in both treatments. Synechococcus spp. Form IA rbcL clones most closely related to the coastal strain Synechococcus sp. strain CC9902 were recovered throughout the experiment but were particularly numerous toward the end of the experiment and dominated the “Green-type” libraries at this time. Initially, rbcL clones from these cyanobacteria were mostly derived from the ambient CO2 mesocosms but were equally distributed between treatments by the end of the experiment. This suggests that cyanobacteria related to strain CC9902 may be less tolerant of elevated CO2 (which was greatest at the beginning rather than the end of the experiment). However, despite the mesocosms being Pi-limited at the end of the experiment, several Synechococcus species (including those related to strain CC9902 and another coastal strain, CC9311) thrived. Following on from this observation, Pi uptake and assimilation mechanisms in a Synechococcus species were investigated in the laboratory. This led to the sequencing and characterisation of a pstS gene from the marine cyanobacterium Synechococcus sp. WH 8103. Unlike conventional pstS, it was discovered that the pstS II gene in this organism is constitutively expressed and unresponsive to or only weakly regulated by Pi supply. The use of PstS/pstS as a marker for P-limitation in natural samples, therefore, should be interpreted with caution.
14
Ewe, Daniela [Verfasser]. "Living well with a scrambled metabolism : CO2 fixation and carbohydrate pathways in the diatom Phaeodactylum tricornutum / Daniela Ewe." Konstanz : Bibliothek der Universität Konstanz, 2015. http://d-nb.info/1112604375/34.
15
Aguiar, Kelen Menezes Flores Rossi de. "Síntese de hidroxiuretana-poli(dimetilsiloxano) com diferentes terminações de cadeia via fixação de CO2: síntese, caracterizações e potenciais aplicações." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-26102015-114419/.
Анотація:
Neste trabalho uretanas livres de isocianatos produzidas a partir de um precursor bis(ciclocarbonato) oligomérico contendo segmentos de poli(dimetil siloxano) (CCPDMS) foram sintetizadas. Para tal, utilizou-se diferentes aminas primárias como a 3-aminometil-3,5,5 trimetilciclohexilamina (IPDA) e as monoaminas 3-aminopropil(trietóxisilano) (APTES), feniletilamina (PEA), catecol amina (dopamina) e um decapeptídeo derivado da proteína de adesão de mariscos (mefp-1).O precursor oligomérico CCPDMS foi produzido por fixação de dióxido de carbono em anéis epóxi catalisado por um sal quarternário de amônio, o brometo de tetraetilamônio (BTA). O precursor CCPDMS foi então reagido com as aminas por meio de polimerização por abertura de anel formando hidroxiuretanas derivadas de PDMS (PDMSUr) com diferentes terminações de cadeia. Tendo como terminador de cadeia o APTES, foi possível produzir um material híbrido com domínios inorgânicos de sílica organicamente modificada (ormosil) interligadas com a parte orgânica de PDMS por meio de ligações uretana. Nesta matriz híbrida foram adicionadas diferentes porcentagens mássicas de ácido fosfotúngstico (PWA), variando entre 1% a 55%. Os materiais foram caracterizados quanto à sua estrutura química por técnicas espectroscópicas (Ressonância Magnética Nuclear, Infravermelho, Espectroscopia de Fotoelétrons, MALDI-ToF), propriedade anti-corrosão (espectroscopia de impedância eletroquímica, polarização potenciodinâmica), propriedades superficiais (energia livre superficial, nanoindentação), análise morfológica (Microscopia Eletrônica de Varredura), estabilidade térmica (Análise Termogravimétrica), testes de adesão (pull-off-test e cisalhamento), testes microbiológicos (adesão de bactérias, tecidos e citotoxicidade), além de ensaios de fotocromismo. O polioxometalato PWA conferiu propriedades fotocrômicas aos filmes híbridos de PDMSUr com máxima absorbância de 1,6 u.a após irradiação por luz ultra-violeta (UV). PDMSUr híbridas com ou sem PWA foram testadas como adesivos para vidro, alumínio, aço (SS316L) e liga de titânio (Ti6Al4V) apresentando valores de força de adesão entre 2-7 MPa. Filmes de PDMSUr preparados em diferentes substratos apresentaram comportamento bacteriostático frente à adesão de Escherichia coli (E.coli) e Lactobacillus casei (L.casei). A PDMSUr biomimética terminada por grupos catecóis foi capaz de formar camadas em superfícies metálicas apresentando boa estabilidade frente à remoção da camada depositada por lavagem com etanol.Free isocyanate urethanes produced from an oligomeric precursor bis(cyclic carbonate) bearing poly(dimethylsiloxane) (CCPDMS) were synthesized in this work. Different primary amines such as 3-Aminomethyl-3,5,5-trimethylcyclohexylamine (IPDA) and monoamines 3-aminopropyltriethoxysilane (APTES), phenylethylamine (PEA), catechol amine (dopamine) and a decapeptide derived from marine mussel foot protein (mefp-1). The precursor cyclic carbonate CCPDMS was obtained from carbon dioxide fixation into epoxy rings catalized by a quaternary ammonium salt, tetraethylamonium bromide (TEAB). The precursor CCPDMS was reacted with the different amines by ring opening polymerization affording the formation of hydroxyurethanes PDMS derived (PDMSUr) with different chain terminations. Using APTES as chain terminator was feasible to obtain a hybrid material containing inorganic domains of organically modified silica (ormosil) interconnected to the organic part PDMS through urethane bond. In this hybrid matrix different mass percentages, varying from 1%wt to 55 wt%, of phosphotungstic acid (PWA) were added. The materials were characterized regarding their chemical structure by spectroscopic techniques (Nuclear Magnetic Resonance, Infrared, and X-ray photoelectron spectroscopy), mass spectrometry (MALDI-ToF and GPC), anti corrosive property (Electrochemical Impedance Spectroscopy and potentiodynamic polarization), surface properties (free surface energy, nanoindentation), morphology (Scanning Electron Microscopy), thermal stability (Thermogravimetric analysis), adhesion strenght measurements (pull-off-test and lap-shear), microbiologic assays (bacteria adhesion, tissue adhesion and citotoxicity test) besides photochromic assays. The polyoxometalate PWA provided photochromic property to the PDMSUr hybrid films presenting a maximum absorbance of 1.6 a.u after ultraviolet (UV) irradiation. Hybrids PDMSUr with or without PWA were tested as adhesive for glass, aluminium, steel (SS316L) and titanium alloy (Ti6Al4V) showing adhesion strength values ranging from 2-7 MPa. PDMSUr films prepared on different substrates showed bacteriostatic behavior against Escherichia coli (E.coli) and Lactobacillus casei (L.casei). The biomimetic PDMSUr catechol endcapped was able to form a layer on metallic surfaces showing good stability after rinsing with ethanol.
16
Temperton, Victoria Martine. "The effects of nitrogen uptake and nitrogen fixation on trees grown in elevated [CO2] : Alnus glutinosa and Pinus sylvestris." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/13101.
Анотація:
There has been much research into the impact of rising [CO2] on growth and physiology of plants. Trees, being long-lived organisms which often exist in nutrient-limited soils, are especially relevant to the study of the long-term impact of rising [CO2], not least because they play an important role in the global carbon cycle. Their response to rising [CO2] is complex and often species-specific, because of interactions with other variables such as nutrients, temperature or the ability to fix atmospheric nitrogen. In particular, nitrogen-fixing trees grown in elevated [CO2] should grow better than non-fixers, since they can uncouple growth from soil nutrient availability and use the extra carbon to run the expensive nitrogen-fixing apparatus with greater efficiency and output. The aim of this thesis was to investigate the effects of nutrient uptake and nitrogen fixation on growth and biochemistry in two temperate tree species: Alnus glutinosa and Pinus sylvestris. The former is a nitrogen-fixing deciduous species, the latter a mycorrhizal conifer. One short-term experiment (15 weeks) and one long-term experiment (three years) were set up, both using seedlings grown in open top chambers (OTCs). In the short-term experiment, c. 90 one-year old Alnus seedlings (alder) and 85 one-year old Pinus seedlings (Scots pine) in pots were exposed to either ambient or ambient + 350 μmol mol-1 [CO2] for fifteen weeks. They were supplied with either a high nitrogen (N) fertiliser designed to allow maximum growth, or a low nitrogen fertiliser. Growth was measured weekly and two harvests were made, one at the beginning and one at the end of the experiment. Other variables measured were leaf area, stem basal diameter, chlorophyll concentrations, nutrient concentrations, and soluble carbohydrate and starch concentrations.
17
Mangiapia, Mary Ann. "From CO2 to Cell: Energetic Expense of Creating Biomass Using the Calvin-Benson-Bassham and Reductive Citric Acid Cycles Based on Genomic Data." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5264.
Анотація:
Abstract
The ubiquity of the Calvin-Benson-Bassham cycle (CBB) amongst autotrophic organisms suggests that it provides an advantage over a wide range of environmental conditions. However, in some habitats, such as hydrothermal vents, the reductive citric acid cycle (rCAC) is an equally predominant carbon fixation pathway. It has been suggested that the CBB cycle poses a disadvantage under certain circumstances due to being more energetically demanding compared to other carbon fixation pathways. The purpose of this study was to compare the relative metabolic cost of cell biosynthesis by an autotrophic cell using either the CBB cycle or the rCAC. For both pathways, the energy, in ATP, required to synthesize the macromolecules (DNA, RNA, protein, and cell envelope) for one gram of biomass was calculated, beginning with CO2. Two sulfur-oxidizing chemolithoautotrophic proteobacteria, Thiomicrospira crunogena XCL-2, and Sulfurimonas autotrophica were used to model the CBB cycle and rCAC, respectively while Escherichia coli was used to model both pathways because it has had its cell composition extremely well-characterized. Since these organisms have had their genomes sequenced, it was possible to reconstruct the biochemical pathways necessary for intermediate and macromolecule synthesis. Prior estimates, based solely on the ATP cost of pyruvate biosynthesis, suggested that the cellular energetic expense for biosynthesis from the CBB cycle was more than that from the rCAC. The results of this study support this conclusion; however the difference in expense between the two pathways may not be as extreme as suggested by pyruvate synthesis. Other factors, such as oxygen sensitivity, may act in concert with energetic expense in contributing to the selective advantages between different autotrophic carbon fixation pathways.
18
Nogueira, Rodrigo Bíscaro. "Obtenção e caracterização de poliuretanos sem o uso de isocianatos (NIPU) e com fixação de CO2." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-24032011-090501/.
Анотація:
Neste trabalho, foi estudada uma rota alternativa para síntese de poliuretanos sem a utilização de isocianatos (NIPU) por um processo de fabricação seguro e utilizando CO2 como insumo. A produção destes poliuretanos \"verdes\" ocorreu através da reação entre ciclocarbonatos e diaminas. A caracterização da estrutura química e a análise dos produtos da reação de formação dos poliuretanos foi possível com a utilização de espectroscopia de infravermelho com transformada de Fourier (FTIR) e espectroscopia de ressonância magnética nuclear (RMN). Foram sintetizados também os ciclocarbonatos pela reação de cicloadição de CO2 ao grupo oxirano de uma resina epóxi e o co-catalisador (resinato de zinco) utilizado na obtenção dos carbonatos cíclicos. Para otimização da formação dos ciclocarbonatos desenvolveu-se um reator de síntese, o qual permitiu a análise do rendimento da reação em função dos parâmetros de síntese controlados: pressão de CO2, temperatura do meio reacional, tempo de síntese, gaseificação da resina epóxi com CO2 (por agitação mecânica ou sistema de refluxo de CO2) e fonte de aquecimento (convencional ou utilizando radiação de microondas). A estrutura química do carbonato obtido, o rendimento e os possíveis subprodutos da reação de cicloadição também foram analisados por FTIR e RMN.Seeking to optimize the formation of ciclocarbonates, it was developed a reactor in a closed system (no atmospheric emissions of CO2) in which the parameters of synthesis could be controlled: CO2 pressure, temperature of the reaction medium, distribution and concentration of CO2 gas bubbles in epoxy resin. The development of the ciclocarbonate synthesis\'s reactor included new systems to improve the gas-liquid contact between the reactants (aerator and CO2 reflux system) and also a heating system using microwave radiation. It were synthesized in this research, the co-catalyst (zinc resinate), the ciclocarbonate under different conditions of: pressure, temperature, synthesis time, heating source, aeration and catalyst, and \"green\" polyurethanes by an alternative route instead of the use of isocyanates, which have potential in specific applications (control of properties through chemical structure of the polymer). The result of the carbonates formation reaction was analyzed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (RMN) to obtain the carbonates\'s chemical structure\'s, yield and the reaction\'s by-products. Non-isocyanate polyurethanes (NIPU) were obtained from a manufacturing process and secure using CO2 as an input. The characterization of the chemical structure and the yield and by-product\'s analysis of the polyurethanes formation reaction also happened by FTIR and RMN.
19
Alves, Átila Nascimento. "CO2 como matéria prima: materiais híbridos do tipo uretanosil obtidos a partir de monômeros de poli(dimetil siloxano) e bisfenol A." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-23102018-160019/.
Анотація:
Materiais dielétricos flexíveis e filmogênicos são essências para a produção de diversos dispositivos tecnológicos, tais como Organic Light Emiting Diodes (OLED), Transistores de Efeito de Campo (FET do Inglês Field Emission Transistor) ou fotovoltaicos orgânicos (OPV do Inglês Organic Photovoltaics). Dentro deste contexto, é importante salientar o esforço de desenvolver rotas sintéticas mais sustentáveis baseadas em matérias-primas e processos mais amigáveis ao meio ambiente. No Grupo de Química de Materiais Híbridos e Inorgânicos (GQMATHI) há mais de dez anos se pesquisa rotas sintéticas de preparação de oligômeros e polímeros de uretanas usando CO2 como matéria-prima. Assim, são sintetizados os materiais classificados como polihidroxi-uretânicos, que são obtidos a partir do monômero bis-ciclocarbonato de polidimetilsiloxano (CCPDMS) mediante a reação de polimerização por abertura de anel (ROP - do inglês Ring Oppening Polymerization). O monômero é obtido pela reação de cicloadição de CO2 no seu respectivo epóxido: poli(dimetil-siloxano) diglicidil éter (PDMS). Neste projeto os materiais hidroxi-uretânicos foram sintetizados, utilizando tanto o CCPDMS como monômero precursor da reação, como o ciclocarbonato de bisfenol A diglicidil éter (CCDGEBA). O oligômero formado foi ensaiado em diferentes proporções destes dois ciclocarbonatos na reação frente à uma diamina (5-Amino-1,3,3-trimetilciclohexanometilamina ,IFDA). Utilizou-se como grupo terminador de cadeia o 3-aminopropiltrietóxissilano (APTS). Os ciclocarbonatos foram caracterizados por espectroscopia vibracional (FTIR) e de ressonância magnética nuclear (RMN) de 13C e 1H. Na espectroscopia vibracional a formação do grupamento ciclocarbonato foi obtida pela presença da banda de carbonila em 1790 cm-1 , enquanto na RMN os sinais do duplo dubleto próximo de 4,5 ppm (1H) e o pico em 154 ppm (13C) foram interpretados como sinais carcaterísticos do grupo ciclocarbonato. O material oligomérico sintetizado a partir dos ciclocarbonatos foi caracterizado por análise termogravimétrica (TGA), calorimetria diferencial de varredura (DSC), análise dinâmico-mecânica (DMA) bem como filmes dos mesmos foram preparados via spin coating. Os filmes foram caracterizados eletricamente por medidas de espectroscopia de impedância, visando avaliar a possibilidade do material ser utilizado como camada dielétrica em transístores orgânicos do tipo FET. Visando um melhor desempenho do material hidroxi-uretânico nesta aplicação o dióxido de titânio (constante dielétrica (ε) ≈ 100) foi introduzido na matriz polimérica. Assim sendo, a introdução desta cerâmica classificará o material formado como um material compósito do tipo híbrido inorgânico-orgânico. Este híbrido também foi caracterizado por espectroscopia de impedância revelando um aumento da constante dielétrica, porém um aumento da perda dielétrica também foi observada para o híbrido.Flexible and film-forming dielectric materials are essential for the production of various technological devices, such as Organic Light Emitting Diodes (OLED), Field Effect Transistors (FETs) or organic photovoltaics (OPVs). Within this context, it is important to highlight the effort to develop more sustainable synthetic routes based on raw materials and more environmentally friendly processes. In the Group of Chemistry of Hybrid and Inorganic Materials (GQMATHI) more than ten years ago, synthetic routes for preparation of oligomers and polymers of urethanes using CO2 as raw material have been investigated. Thus, materials classified as polyhydroxy urethanes, which are obtained from the bis-cyclocarbonate monomer of polydimethylsiloxane (CCPDMS) are synthesized by the Ring Oppening Polymerization (ROP) reaction. The monomer is obtained by the cycloaddition reaction of CO2 in its respective epoxide: poly (dimethylsiloxane) diglycidyl ether (PDMS). In this project the hydroxy urethane materials were synthesized, using two different types of precursor monomer : the CCPDMS and bisphenol A diglycidyl ether cyclocarbonate (CCDGEBA). The oligomer formed was tested in different ratios of these two cyclocarbonates in the reaction against a diamine (5-Amino-1,3,3-trimethylcyclohexanemethylamine (IFDA)). The aminopropyltriethoxysilane (APTS) was used as the chain terminator group. After the synthesis of the cyclocarbonates, characterizations were made by vibrational spectroscopy (IR) and nuclear magnetic resonance (NMR) of 13C and 1H. The successful formation of the cyclocarbonate was confirmed by the 1790 cm-1 peak in the vibrational spectroscum as well as by the dublet near 4.5 ppm (1H NMR) and the singlet at 154 ppm (13 C NMR). The oligomeric hydroxyurethane synthesized from the cyclocarbonates reaction with IFDA and APTS was characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA) and films were prepared by spin coating. The electrical characterization of the films was made by impedance spectroscopy, aiming to evaluate its application on organic FET´s as adielectric layer . In order to improve the performance of the hydroxy urethane material for this application, titanium dioxide (dielectric constant (ε) ≈ 100) was incorporated into the oligomer matrix, thus an hybrid nanocomposite material was formed. The impedance chacacterization of the hybrid was performed showing higher dielectric constant for this new material, although observed a higher dielectric loss, 9 vs 0,2 ,respectively for the hydroxyurethane and the hybrid.
20
González, Fabra Joan. "Computational Design of Catalysts for Carbon Dioxide Recycling." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/664728.
Анотація:
La utilització del diòxid de carboni com a substrat s'ha convertit en una estratègia popular des d'una perspectiva ambiental i econòmica per mitigar les emissions de CO2 a l'atmosfera i, al mateix temps, reduir la dependència del petroli per proporcionar substrats amb carboni. L'activació del diòxid de carboni és un procés complicat a causa de la seva estabilitat.
El disseny de nous catalitzadors és una tasca complexa que requereix la combinació de tècniques experimentals i teòriques. Una d'aquestes és la modelització molecular, que permet descriure detalladament el sistema i comprendre com es comporta, o com té lloc un mecanisme de reacció. La combinació de dos factors, com l'augment de la potència computacional i la millora de l'eficiència dels algoritmes, ens permet estudiar grans sistemes amb un nivell raonable de precisió, imitar les condicions experimentals i, en conseqüència, obtenir informació crucial.
En aquesta Tesi estudiem computacionalment diverses reaccions on es fa servir diòxid de carboni com a substrat. Descrivim detalladament el mecanisme de reacció tenint en compte els resultats experimentals proporcionats pels nostres col·laboradors. Els nostres resultats contribueixen a entendre millor com funcionen les reaccions de fixació de CO2 i, en conseqüència, pot ajudar al disseny racional de nous i més actius catalitzadors per a reaccions que involucren CO2 o substrats similars.La utilización del dióxido de carbono como sustrato se ha convertido en una popular estrategia desde una perspectiva ambiental y económica para mitigar las emisiones de CO2 a la atmósfera y, al mismo tiempo, reducir la dependencia del petróleo para proporcionar sustratos con carbono. La activación del dióxido de carbono es un proceso complicado debido a su estabilidad. El diseño de nuevos catalizadores es una tarea compleja que requiere la combinación de técnicas experimentales y teóricas. Una de estas es la modelización molecular, que permite describir detalladamente el sistema y comprender cómo se comporta, o cómo tiene lugar un mecanismo de reacción. La combinación de dos factores, como el aumento de la potencia computacional y la mejora de la eficiencia de los algoritmos, nos permite estudiar grandes sistemas con un nivel razonable de precisión, imitar las condiciones experimentales y, en consecuencia, obtener información crucial. En esta Tesis estudiamos computacionalmente varias reacciones en las que se usa dióxido de carbono como sustrato. Describimos detalladamente el mecanismo de reacción teniendo en cuenta los resultados experimentales proporcionados por nuestros colaboradores. Nuestros resultados contribuyen a comprender mejor cómo funcionan las reacciones de fijación de CO2 y, en consecuencia, puede ayudar en el diseño racional de nuevos y más activos catalizadores para reacciones que involucran CO2 o sustratos similares.
The utilization of carbon dioxide as chemical substrate has become a popular strategy from an environmental and economic perspective to mitigate CO2 emissions to the atmosphere and, at the same time, reduce the petroleum dependency to provide carbon based substrates. The activation of carbon dioxide is not a straightforward process. The design of new catalysts is a complex task that requires the combination of several experimental and theoretical techniques. One of the most relevant is molecular modelling, which allow to describe the system in detail and to understand how the system behaves or how a reaction mechanism takes place. Nowadays, the combination of two factors, being the increase of the computational power and the improved efficiency of the theoretical algorithms, enable computational chemists to study large systems at a reasonable level of accuracy, to mimic the experimental conditions, and consequently, obtain crucial information on the studied system. In this Thesis we studied computationally several reactions where carbon dioxide was used as substrate. We described in detail the reaction mechanism for all cases, taking into consideration the experimental results provided by our collaborators. The results collected in this Thesis contribute to understand better how important CO2 fixation reactions work and consequently, these results may help in the rational design of new and more active catalysts for this type of reactions involving CO2 or substrates of similar properties.
21
Filali, Rayen. "Estimation et commande robustes de culture de microalgues pour la valorisation biologique de CO2." Phd thesis, Supélec, 2012. http://tel.archives-ouvertes.fr/tel-00765421.
Анотація:
Cette thèse s'attache à la maximisation de la consommation du dioxyde de carbone par les microalgues. En effet, suite aux différentes problématiques environnementales actuelles liées principalement aux émissions importantes de gaz à effet de serre et notamment le CO2, il a été démontré que les microalgues jouent un rôle très prometteur pour la bio-fixation du CO2. Dans cette optique, nous nous intéressons à la mise en place d'une loi de commande robuste permettant de garantir des conditions opératoires optimales pour une culture de la microalgue Chlorella vulgaris dans un photobioréacteur instrumenté. Cette thèse repose sur trois axes principaux. Le premier porte sur la modélisation de la croissance de l'espèce algale choisie à partir d'un modèle mathématique traduisant l'influence de la lumière et de la concentration en carbone inorganique total. En vue de la commande, le deuxième axe est consacré à l'estimation de la concentration cellulaire à partir des mesures disponibles en temps réel du dioxyde de carbone dissous. Trois types d'observateurs ont été étudiés et comparés : filtre de Kalman étendu, observateur asymptotique et observateur par intervalles. Le dernier axe concerne l'implantation d'une loi de commande prédictive non-linéaire couplée à une stratégie d'estimation pour la régulation de la concentration cellulaire autour d'une valeur maximisant la consommation du CO2. Les performances et la robustesse de cette commande ont été validées en simulation et expérimentalement sur un photobioréacteur instrumenté à l'échelle de laboratoire. Cette thèse est une étude préliminaire pour la mise en œuvre de la maximisation de la fixation du dioxyde de carbone par les microalgues.
22
Vincent, Marine. "Ingénierie métabolique de cyanobactéries pour la production photosynthétique de terpènes." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL158.
Анотація:
Les cyanobactéries peuvent produire des composés d'intérêt industriel, à partir de l'énergie solaire, d'eau (même polluée) et de CO₂. Au laboratoire on s'intéresse aux terpènes car ils sont volatiles (faciles à récolter), dotés d'odeurs agréables ("intérêt cosmétique") et d'une forte densité énergétique ("intérêt biocarburant").Notre approche met à profit la diversité physiologique des cyanobactéries et la diversité chimique des terpènes dans l'objectif futur de générer des productions économiquement viables. Ainsi, j'ai travaillé avec deux cyanobactéries modèles différentes, Synechocystis PCC 6803 (S.6803) et Synechococcus PCC 7002 (S.7002), qui sont capables de croître dans des eaux salées (plus abondantes que l'eau douce). Nous avons construit des souches productrices de terpènes génétiquement stables. Nous avons montré, pour la première fois, que S.6803 peut produire du farnésène, et aussi du santalène (jamais produit par une cyanobactérie auparavant (Blanc-Garin et al., 2022), et que S.7002 peut produire du farnésène (Chenebault et al., 2023). Chez ces deux cyanobactéries, la production de terpènes augmente parallèlement à l'expression des gènes (ts) codant pour les terpènes synthases (Blanc-Garin et al., 2022 ; Chenebault et al., 2023). Les productions de terpènes chez S.6803 cultivée en nitrate (la source d'azote classique) ou en urée (moins coûteuse) sont équivalentes. Par contre chez S.7002, la production de terpènes est meilleure avec l'urée (Blanc-Garin et al., 2022 ; Chenebault et al., 2023).Comme S.6803 produit mieux le farnésène que les autres terpènes (et mieux que S.7002), et que S.7002 produit mieux le limonène que S.6803 (Chenebault et al., 2023), nous avons travaillé à améliorer ces producteurs. J'ai analysé l'influence de la fixation, distribution et/ou stockage de carbone sur la production de terpènes. La surexpression des gènes codant pour la RuBisCO et la phosphoribulokinase a augmenté la production du farnésène chez S.6803, mais pas du limonène chez S.7002 (manuscrit en préparation). Par contre, la production de farnésène chez S.6803 n'augmente pas lorsque l'on tente d'économiser le carbone, en interrompant la synthèse de polyhydroxybutyrates ou en interférant avec la synthèse des caroténoïdes. En partie conformément à notre attente, j'ai montré que la surexpression chez S.7002 du gène crtE de S.6803 (crtE₆₈₀₃), mais pas de crtE₇₀₀₂, augmente la production de farnésène (manuscrit en préparation). Par contre, chez S.6803 la surexpression de crtE₆₈₀₃ ou de crtE₇₀₀₂ n'augmente pas la production de farnésène ni de limonène. L'ensemble de ces résultats valide l'intérêt de prendre en compte la diversité biologique des cyanobactéries, et chimique des terpènes, pour générer, à terme, de bons producteurs.Pour éviter que les cyanobactéries génétiquement modifiées (OGM) s'échappent de leurs bioréacteurs, nous avons vérifié chez S.6803 que la délétion des gènes ccmK3 et ccmK4 impliquées dans l'assemblage du carboxysome, génère des souches incapables de pousser en condition de faible teneur en CO₂ qui règne dans les milieux naturels. Ces mutants ∆ccmK3-ccmK4 conservent la capacité à produire le limonène (production faible donc peu "gourmande" » en CO₂). Par contre, ils produisent le farnésène moins efficacement que la souche sauvage (manuscrit en préparation).Enfin, dans l'objectif à terme de produire des terpènes sans utiliser de nitrate ou d'urée, j'ai travaillé avec deux cyanobactéries capables d'utiliser le N₂ atmosphérique : Cyanothece PCC 7822 (C.7822) et Gloeothece PCC 6909 (G.6909). J'ai établi un protocole de conjugaison efficace pour G.6909 qui m'a permis d'introduire nos plasmides producteurs de terpènes (les productions sont faibles). Par contre, C.7822 s'est révélée réfractaire à la conjugaisonCyanobacteria can produce compounds of industrial interest, from solar energy, water (even polluted) and CO₂. In the laboratory we are interested in terpenes because they are volatile (easy to harvest), have good smells ("cosmetic interest") and a high energy density ("biofuel interest").Our approach takes advantage of the physiological diversity of cyanobacteria and the chemical diversity of terpenes with the future objective of generating economically viable production. Thus, I worked with two different model cyanobacteria, Synechocystis PCC 6803 (S.6803) and Synechococcus PCC 7002 (S.7002), which are capable of growing in salt water (more abundant than fresh water). We have constructed genetically stable terpene producing strains. We have shown, for the first time, that S.6803 can produce farnesene, and also santalene (never produced by a cyanobacterium before (Blanc-Garin et al., 2022), and that S.7002 can produce farnesene (Chenebault et al., 2023). In these two cyanobacteria, the production of terpenes increases in parallel with the expression of genes (ts) coding for terpene synthases (Blanc-Garin et al., 2022; Chenebault et al., 2023). The production of terpenes in S.6803 cultivated in nitrate (the classic nitrogen source) or in urea (less expensive) is equivalent. On the other hand, in S.7002, the production of terpenes is better with urea (Blanc-Garin et al., 2022; Chenebault et al., 2023).As S.6803 produces farnesene better than other terpenes (and better than S.7002), and S.7002 produces limonene better than S.6803 (Chenebault et al., 2023), we worked to improve these producers. I analyzed the influence of carbon fixation, distribution and/or storage on terpene production. Overexpression of the genes encoding RuBisCO and phosphoribulokinase increased the production of farnesene in S.6803, but not limonene in S.7002 (manuscript in preparation). On the other hand, farnesene production in S.6803 does not increase when trying to save carbon, by interrupting the synthesis of polyhydroxybutyrates or by interfering with the synthesis of carotenoids. Partly consistent with our expectation, I showed that overexpression in S.7002 of the crtE gene from S.6803 (crtE₆₈₀₃), but not crtE₇₀₀₂, increases farnesene production (manuscript in preparation). On the other hand, in S.6803, the overexpression of crtE₆₈₀₃ or crtE₇₀₀₂ does not increase the production of farnesene or limonene. All of these results validate the interest in taking into account the biological diversity of cyanobacteria, and the chemical diversity of terpenes, to generate good producers.To prevent genetically modified cyanobacteria (GMO) from escaping from their bioreactors, we verified in S.6803 that the deletion of the ccmK3 and ccmK4 genes involved in the assembly of the carboxysome, generates strains unable of growing in conditions of low CO₂ content which reigns in natural environments. These ∆ccmK3-ccmK4 mutants retain the capacity to produce limonene (low production and therefore not very "greedy" in CO₂). On the other hand, they produce farnesene less efficiently than the wild type strain (manuscript in preparation).Finally, with the ultimate goal of producing terpenes without using nitrate or urea, I worked with two cyanobacteria capable of using atmospheric N₂: Cyanothece PCC 7822 (C.7822) and Gloeothece PCC 6909 (G .6909). I established an efficient conjugation protocol for G.6909 which allowed me to introduce our terpene-producing plasmids (productions are low). On the other hand, C.7822 proved to be refractory to conjugation
23
Fan, Li. "Novel investigations of sulfimide systems." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8027.
Анотація:
S,S-diphenyl sulfimide (Ph2SNH) has been employed in current investigations divided in three different directions, concerning hydrogen bonding motifs of new sulfimide systems, polymorphism of trans- Cu(Ph2SNH)2Cl2 as well as carboxylations of Ph2SNH. The isomorphic analogues of [Mn(Ph2SNH)6]Cl2 and [Co(Ph2SNH)6]Cl2 were synthesised as parent systems, with their derivatisations by metathesis to give BF4 and PF6 salts. The BF4 daughter systems displayed face on and snug fit hydrogen bonding motifs in the Mn(II) and Co(II) variants respectively. The PF6 analogues were the first examples to have spectator sulfimide units not participating in hydrogen bonds, rationalised as means to relief steric constrains. [Co(Ph2SNH)4]SO4 was observed to be stabilised by the formation of l-D hydrogen bond array between the unsaturated complex centres with SO4 anions. The square planar polymorph of trans- Cu(Ph2SNH)2Cl2 has recently been observed to display reversible mechanochromism when ground. The yielding of a green ground collective was reasoned as the formation of an amorphous conformer closely related to the green pseudotetrahedral polymorph. The concomitant crystallisation of both forms has also been revisited. Internal voids, ether partial pressure and volume of mother liquor have been proposed as contributing factors concerning the crystallisation outcomes. The reaction between Ph2SNH and CO2 led to the formation of [Ph2SNH2]HCO3, Ph2SN(H)COO as well as Ph2SNCOOH, depending on reaction conditions. The zwitterion of Ph2SN(H)COO is expected to be the principle product of Ph2SNH/CO2 reactions, while [Ph2SNH2]HCO3 was deduced as a hydrolysis product of Ph2SN(H)COO. The isolation of Ph2SNCOOH was only possible when CO2 fixation was carried out in DMSO, rationalised as a unique proton transfer equilibrium only attainable in the protophilic solvent.
24
Mota, Cadenas César. "Fijación de CO2 en cultivos y sus implicaciones en el cambio climático." Doctoral thesis, Universidad de Murcia, 2011. http://hdl.handle.net/10803/38711.
Анотація:
El CO2 es una variable clave que afecta tanto al desarrollo como a la fisiología de las plantas, por lo que los incrementos derivados del cambio climático afectarán al crecimiento de los cultivos. Muchas de las respuestas fisiológicas observadas frente al aumento del CO2 están influenciadas por su interacción con otros estreses, como por ejemplo la salinidad, debido al creciente aumento de las áreas afectadas por la salinidad y su impacto sobre la masa vegetal. Por ello, en esta Tesis, se expone como la agricultura desarrolla una función muy importante en la lucha contra el cambio climático debido a su papel como secuestradores de CO2 atmosférico. Las conclusiones de este trabajo ayudarán a clarificar aspectos esenciales para elegir las soluciones más efectivas en este ámbito junto con otras problemáticas dadas en nuestras tierras de cultivos como son el estrés salino, el cual se verá implementado por dicho cambio climático.CO2 is a variable key that affects both development and the plant physiology, so that the increases resulting from climate change will affect crop growth. Many of the observed physiological responses to increased CO2 in front are influenced by its interaction with other stresses, such as salinity, due to the increasing of the areas affected by the salinity and its impact on the vegetation. Therefore, in this thesis agriculture is exposed as a very important place in the fight against climate change due to its role as kidnappers of atmospheric CO2. The conclusions of this work help clarify what is essential to choose the best solutions effective in this area along with other issues given in our crop lands such as salt stress, which will be implemented by the climate change
25
Finn, Michael W. "Discovery of a biochemical pathway to generate ribulose 1,5-bisphosphate and subsequent CO2 fixation through ribulose carboxylase/oxygenase (rubisCO) in Methanococcus jannaschii." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1077915999.
Анотація:
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xiii, 149 p.; also includes graphics. Includes abstract and vita. Advisor: F. Robert Tabita, Dept. of Microbiology. Includes bibliographical references (p. 144-149).
26
Bringuier, Charline. "Effet des changements climatiques et atmosphériques sur la croissance et la fixation biologique de l'azote chez Anabaena variabilis : importance des disponibilités du molybdène et du phosphore." Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8790.
Анотація:
La fixation biologique d’azote réalisée par les cyanobactéries est un processus important dans les écosystèmes où la productivité est limitée par la disponibilité de l’azote. Dans des conditions de changements globaux, l’augmentation du CO2 atmosphérique pourrait engendrer une augmentation des taux de fixation d’azote permettant de combler la demande croissante d’azote nécessaire à la croissance. Cependant cette augmentation des taux de fixation d’azote pourrait dépendre des disponibilités en molybdène (Mo) et en phosphore (P), mais également être contrebalancée par l’azote minéral apporté via les dépositions atmosphériques.
La complexité des systèmes naturels, notamment les caractéristiques de la symbiose cyanobactérie-végétaux supérieurs rends difficile l’étude de l’effet de l’augmentation du CO2 et des dépositions atmosphérique sur la fixation d’azote, dépendamment des disponibilités en Mo et P. Nous avons donc tenté de déterminer les effets de ces facteurs environnementaux (CO2 et apport d’azote minéral), en utilisant des cultures pures de cyanobactéries (Anabaena variabilis) dans différentes conditions de disponibilités en Mo et P. Cette approche expérimentale réductionniste nous a permis de mettre en évidence un effet significatif du P sur la concentration de la chlorophylle, indépendant des conditions environnementales (CO2, N) ainsi qu’une interaction entre le Mo et le P pour la variable chlorophylle, dans des conditions de CO2 augmenté sans apport d’azote. Cette interaction entre le Mo et le P pourrait être expliquée par un compromis entre l’acquisition du carbone, facilitée dans des conditions de CO2 augmentée, et la fixation biologique d’azote. Notre étude a également permis de mettre en évidence un effet significatif du P sur la croissance d’A. variabilis, dans des conditions de CO2 ambient et en présence d’azote. De façon plus spécifique, à haut P (2.5 10-5 M) le taux de croissance était plus faible (P = 0.02), alors que la quantité de chlorophylle et l’activité de la nitrogénase étaient toutes deux plus élevée (P = 0.002 et P = 0.015 respectivement). Cet effet du P pourrait être expliqué par une différence de stratégie de croissance de la cyanobactérie. A faible P, la cyanobactérie pourrait investir dans de courts filaments composés de cellules volumineuses, contrairement à des conditions de concentration en P élevées, où la cyanobactérie pourrait investir plus dans la formation d’hétérocystes et de filaments plus longs, composés de cellules plus petites.
Cette étude apporte des pistes de réflexion quant aux stratégies permettant aux cyanobactéries filamenteuses de s’adapter à l’augmentation du CO2 atmosphérique et des dépositions azotées, en fonction des disponibilités en Mo et P. Un compromis entre l’acquisition de C et la fixation d’azote ou un changement de la stratégie de croissance des filaments pourrait permettre aux cyanobactéries filamenteuses d’être moins sensibles aux stress environnementaux (augmentation du CO2 atmosphérique et disponibilité des nutriments tels que l’azote).
27
Sporre, Emil. "Identification of metabolite-protein interactions among enzymes of the Calvin Cycle in a CO2-fixing bacterium." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278729.
Анотація:
The Calvin – Benson cycle is the most widespread metabolic pathway capable of fixing CO2 in nature and a target of very high interest to metabolic engineers worldwide. In this study, 12 metabolites (ATP, AMP, NADP, NADPH, 2PG, 3PGA, FBP, RuBP, PEP, AKG, Ac-CoA and phenylalanine) were tested for protein – metabolite interactions against the proteome of Cupriavidus necator (previously Ralstonia eutropha) in the hopes of finding potential examples of allosteric regulation of the Calvin – Benson cycle. This is accomplished through the use of the LiP-SMap method, a recently developed shotgun proteomics method described by Piazza et al. capable of testing a metabolite of interest for interactions with the entire proteome of an organism at once. A functional protocol was developed and 234 protein – metabolite interactions between ATP and the proteome of C. necator are identified, 103 of which are potentially novel. Due to time constraints and setbacks in the lab, significant results were not produced for the other 11 metabolites tested. C. necator is an industrially relevant chemolithoautotroph that can be engineered to produce many valuable products and is capable of growth on CO2 and hydrogen gas. The bacteria were grown in continuous cultures after which the proteome was extracted while retaining its native state. Subsequently, the proteome was incubated with a metabolite of interest and subjected to limited, non-specific proteolysis. The resulting peptide mix was analyzed by liquid chromatography coupled tandem mass spectrometry (LC – MS/MS).Calvin-Benson-cykeln är den mest utbredda metaboliska processen i naturen med vilken det är möjligt att fixera CO2 och en måltavla av högsta intresse för bioteknologer världen över. I den här studien testades 12 metaboliter (ATP, AMP, NADP, NADPH, 2PG, 3PGA, FBP, RuBP, PEP, AKG, Ac-CoA and phenylalanine) för interaktioner mot proteomet från Cupriavidus necator (tidigare Ralstonia eutropha) i hopp om att hitta potentiella exempel på allosterisk reglering av Calvin-Benson-cykeln. Detta uppnåddes genom användning av LiP-SMap-metoden, en nyligen utvecklad proteomikmetod beskriven av Piazza et al. kapabel av att testa en metabolit av intresse mot en organisms hela proteom simultant. Ett funktionellt protokoll utvecklades och 234 interaktioner mellan ATP och proteomet av C. necator identifierades, varav 103 potentiellt är nyupptäckta. På grund av tidsbrist och motgångar i labbet producerades inga signifikanta resultat för de resterande 11 metaboliterna som testades. C. necator är en industriellt relevant kemolitoautotrof som kan växa på CO2 och vätgas, samt manipuleras till att producera många värdefulla produkter. Bakterierna odlades i kemostater varefter proteomet extraherades i sitt naturliga tillstånd. Sedan inkuberades proteomet med en metabolit av intresse och utsattes för begränsad, icke-specifik proteolys. Den resulterande peptidblandningen analyserades via tandem masspektrometri kopplad till vätskekromatografi (LC – MS/MS).
28
Sakuragi, Hiroshi. "Studies on applications of Clostridium species for biorefinery." Master's thesis, Kyoto University, 2014. http://hdl.handle.net/2433/188770.
Анотація:
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第18332号
農博第2057号
新制||農||1023(附属図書館)
学位論文||H26||N4839(農学部図書室)
31190
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 植田 充美, 教授 渡邊 隆司, 教授 梅澤 俊明
学位規則第4条第1項該当
29
Ferrand-Roumet, Catherine. "Importance et devenir du CO2 fixé par les racines nodulées de soja (Glycine max L. Merrill) : incidence sur l'estimation du coût carboné de la fixation de N2." Montpellier 2, 1990. http://www.theses.fr/1990MON20196.
Анотація:
La fixation de co#2 par les racines nodulees de soja a ete mesuree en exposant les systemes racinaires a une atmosphere enrichie en #1#4co#2. Un suivi de l'importance et du devenir du #1#4c incorpore dans les plantes en fonction du temps apres le marquage, a permis d'etudier la dynamique d'utilisation du c fixe, en relation avec l'activite nitrogenase, et ce pour differents stades phenologiques et dans des conditions environnementales variables. Les resultats ont montre qu'une fraction importante du c fixe etait respiree par les racines nodulees et que les quantites de c incorporees dans les tissus (fixation nette), et sa repartition dans les organes, n'etaient pas directement liees a la fixation de n#2. Ceci nous a amene a augurer de l'existence d'une fixation racinaire, dont l'importance relative a ete estimee en comparant la fixation de co#2 de soja denodules et de soja nodules. Il a ete montre que la fixation racinaire contribuait pour plus de 50% a l'activite totale des racines nodulees et qu'il existait une relation entre fixation nodulaire de co#2 et activite nitrogenase. Une specificite des racines et des nodosites pour l'utilisation du c fixe a ete mise en evidence: le c fixe par les racines est principalement exporte vers les tiges; le c fixe par les nodosites est incorpore dans les racines et les nodosites. Dans ces organes une fraction de ce c est respiree; dans les nodosites, cette derniere fraction servirait de substrat respiratoire a la nitrogenase. La fixation de co#2 contribue pour 2,4 a 3,8% a la croissance en c de la plante, selon la periode du cycle, elle permet de recycler 8 a 37% du co#2 respire par les racines nodulees et 23 a 40% du co#2 respire par les nodosites pour leurs besoins de fixation de n#2. Le cout reel de la fixation de n#2, estime par le degagement total de co#2 (co#2 degage a l'exterieur des nodosites + co#2 recycle) est de 3,37
30
Perner, Mirjam [Verfasser]. "Comparison of Microbial Communities Inhabiting Ultramafic- and Basalt-Hosted Hydrothermal Systems : Genetic Characterization of 16S rRNA Genes, Hydrogen Oxidation and CO2 Fixation Pathways / Mirjam Perner." Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019552905/34.
31
Nowak, Martin [Verfasser], Susan [Gutachter] Trumbore, Erika [Gutachter] Kothe, and Marcus [Gutachter] Horn. "The role of microbial CO2 fixation for belowground carbon cycling and its influence on carbon isotopic signatures / Martin Nowak ; Gutachter: Susan Trumbore, Erika Kothe, Marcus Horn." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/117759952X/34.
32
Muthusamy, Saraladevi. "Functional Profiling Of Metabolic Regulation In Marine Bacteria." Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-58257.
Анотація:
Oceans are powered by active, metabolically diverse microorganisms, which are important in regulating biogeochemical cycles on Earth. Most of the ocean surface is often limited by nutrients, influencing bacterial growth and activities. Bacterial adaptation to fluctuating environmental conditions involves extensive reprogramming, and redirection of bacterial metabolism and physiology. In this thesis, I investigated the molecular mechanisms of bacterial adaptation strategies to sustain their growth and survival, focusing on the regulation of gene and protein expression in heterotrophic marine bacteria. Comparative proteomics analyses of the growth and non-growth conditions, uncovered central adaptations that marine bacteria employ to allow them to change their metabolism to support exponential growth in response to nutrients and to readjust to stationary phase under nutrient limitation. Our results highlight that during nutrient rich conditions three distinct bacteria lineages have great similarities in their proteome. On the other hand, we observed pronounced differences in behavior between taxa during stationary phase. Analyses of the proteorhodopsin containing bacterium Vibrio sp. AND4 during starvation showed that significantly improved survival in the light compared to darkness. Notably, proteins involved in promoting cell vitality and survival had higher relative abundance under light. In contrast, cells in the dark need to degrade their endogenous resources to support their basic cellular demands under starvation. Thus, light strongly influences how PR-containing bacteria organize their molecular composition in response to starvation. Study of alternative energy generation metabolisms in the Alphaproteobacteria Phaeobacter sp. MED193 showed that the addition of thiosulfate enhanced the bacterial growth yields. Concomitantly, inorganic sulfur oxidation gene expression increased with thiosulfate compared to controls. Moreover, thiosulfate stimulated protein synthesis and anaplerotic CO2 fixation. These findings imply that this bacterium could use their lithotrophic potential to gain additional energy from sulfur oxidation for both improving their growth and survival. This thesis concludes that analyses in model organisms under defined growth conditions gives invaluable knowledge about the regulatory networks and physiological strategies that ensure the growth and survival of heterotrophic bacteria. This is critically important for interpreting bacterial responses to dynamic environmental changes. Moreover, these analyses are crucial for understanding genetic and proteomic responses in microbial communities or uncultivated organisms in terms of defining ecological niches of planktonic bacteria
33
Mochamad, Arief Soleh. "Diversity and Mechanism of the Photosynthetic Induction Response among Various Soybean [Glycine max (L.) Merr.] Genotypes." Kyoto University, 2016. http://hdl.handle.net/2433/215607.
Анотація:
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第19781号
農博第2177号
新制||農||1041(附属図書館)
学位論文||H28||N4997(農学部図書室)
32817
京都大学大学院農学研究科農学専攻
(主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也
学位規則第4条第1項該当
34
Ruiz-Sanchez, Patricia. "Optimisation de la culture de microalgues en milieu vibré : application à Arthrospira platensis." Compiègne, 2008. http://www.theses.fr/2008COMP1761.
Анотація:
Nous avons optimisé la culture d'A. Platensis en bioréacteur. Nous avons caractérisé et mis au point un système de culture qui comporte un bioréacteur en sac plastique fixé à une table vibrante. Une étude comparative entre un système de référence de culture et le système vibré a démontré que la croissance d'A. Platensis est réalisable en milieu vibré. L'optimisation de la culture en milieu vibré a été initialement effectuée à 15000 Lux qui a permis d'obtenir une concentration cellulaire X de 1,0 g/L et une productivité (P) de 0,2 g/Lj. Ensuite, d'autres cultures ont été réalisées à 15000 Lux, puis exposées directement à 31700 Lux. Nous avons démontré qu'à cette dernière intensité, la croissance cellulaire est limitée en carbone. Les valeurs de X et P sont de 1,4 g/L et de 0,3 g/Lj respectivement. Dans ces conditions, la mort cellulaire apparaît à des valeurs de pH supérieures à 11. Pour satisfaire le besoin en carbone, nous avons effectué la culture en photoautotrophie et en mixotrophie avec un contrôle de pH par injection de CO2. Cela a permis de maximiser X et P. En photoautotrophie, X = 3,4 g/L et P = 0,49 g/Lj et en mixotrophie, X = 3,9 g/L et P = 0,57 g/LjIn this work, we aim to develop and characterize a new adapted culture system for A. Platensis. It is based on surface aeration of a flexible pouch bioreactor fixed on a vibrating table. A comparative study between a culture reference system and the vibrated system shows that the growth of A. Platensis is suitable in vibrated culture. The vibrated culture has been firstly optimized by increasing the light at an intensity of 15000 Lux. In these conditions, X reached 1. 0 g/L and P was 0. 2 g/Ld. Furthermore, other cultures were placed at 15000 Lux and then exposed directly to 31700 Lux. It has been showed that at 31700 Lux, the cellular growth is limited by the carbon. The values X and P are respectively 1. 4 g/L and 0. 3 g/Ld. In these conditions, the cellular death appears at pH values higher than 11. To feed microalgae in carbon, we submitted the cellular growth to phototrophic and mixotrophic conditions under pH control using CO2 injection. It allowed to optimize X and P. In phototrophic conditions, X = 3. 4 g/L and P = 0. 49 g/Ld and in mixotrophic conditions, X = 3. 9 g/L and P = 0. 57 g/Ld
35
Cazenave, Alexandre-Brice. "Réponse adaptative à court terme de la fixation symbiotique du pois protéagineux à une ablation d'une partie des racines nodulées, en lien avec la disponibilité en assimilats carbonés." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS018/document.
Анотація:
La fixation symbiotique d’N par les légumineuses est très sensible aux ravageurs, provoquant des dommages sur les racines nodulées, avec un impact sur la fixation d’N et la croissance qui demeure mal connu. Nous avons alors analysé la réponse adaptative de la fixation symbiotique et de la croissance du pois Frisson sauvage et 3 de ses mutants hypernodulants P64, P118 et P121, respectivement mutés sur les gènes SYM28, SYM29 et NOD3, à une ablation de la moitié du système racinaire, en fin de phase végétative. La réponse adaptative a été mesurée 8 jours après ablation, dans des conditions d'alimentation en carbone par la photosynthèse variées. A 380 ppm, le mutant P118 a montré la plus faible diminution de l’activité spécifique de fixation (-17%) suite à l’ablation comparé au sauvage et aux 2 autres mutants (-36% à -62%) associé à une accélération chez les mutants P118 et P121 et un maintien (sauvage et P64) de la croissance des nodosités. A 150 ppm, suite à l’ablation, l’activité spécifique de fixation symbiotique par les nodosités a été diminuée (sauvage), maintenue (P64 et P118) ou augmentée (P121), associée à une accélération (sauvage et P121) ou un maintien (P64 et P118) de la croissance des nodosités. A 750 ppm, l’activité spécifique de fixation a diminué suite à l’ablation pour tous les génotypes, associée à un ralentissement (P64), un maintien (P118, sauvage) ou une faible accélération (P121) de la croissance des nodosités. Les résultats montrent une plus grande capacité de la fixation symbiotique des mutants hypernodulants (P118 et P121 essentiellement) à résister au stress provoqué par l’ablationSymbiotic N fixation of legumes is very sensitive to environmental stresses, like pea pests damaging nodulated roots. However, the impact on their N uptake capacity and plant growth has not been studied so far.We analyzed the adaptive response symbiotic N2 fixation and plant growth of pea wild type Frisson and hypernodulating mutants P64, P118 and P121 mutated respectively on genes SYM28, SYM29 and NOD3 to root pruning of half the root system at the end of the vegetative stage. The adaptive responses of pea: cv. Frisson and 3 of its hypernodulating mutants were compared under varying carbon supplies from photosynthesis.At 380 ppm, mutant P118 showed the lowest decrease of the specific activity of N fixation (-17%) following root pruning compared to the wild type and the 2 others mutants (-36% to -62%), associated to an acceleration (P118 and P121) and a maintained (wild type and P64) nodule growth. At 150 ppm, following root pruning, specific activity of N fixation of nodules decreased in wild type, was maintained in P64 and P118 and increased in P121. At 750 ppm, specific activity of N fixation of nodules decreased for all genotypes following root pruning, associated to a maintained nodule growth in wild type and P118, a slower growth in P64 and acceleration in P121.Our results showed a greater capacity of hypernodulating mutants P118 and P121 to withstand the stress induced by root pruning of half the root system
36
Irion, Solène. "Biodiversité de l'écosystème marin et flux de carbone autour de Kerguelen (Océan Austral) : le rôle du petit phytoplancton à l'échelle de la cellule Marked spatiotemporal variations in small phytoplankton structure in contrasted waters of the Southern Ocean (Kerguelen area) Small phytoplankton contribute greatly to CO2-fixation after the diatom bloom in the Southern Ocean." Thesis, Littoral, 2020. https://tel.archives-ouvertes.fr/tel-03178263.
Анотація:
Cette thèse s'intéresse à la diversité du petit phytoplancton (<20 µm) et à sa contribution à la fixation du carbone dans les écosystèmes marins contrastés : la région productive du plateau de Kerguelen d'une part et les zones à faible productivité en dehors du plateau, d'autre part. Le petit phytoplancton domine les communautés phytoplanctoniques tout au long de l'année en dehors du plateau, où les faibles concentrations en fer limitent la production primaire. Le plateau de Kerguelen, naturellement fertilisé en fer, est quant à lui caractérisé par le développement au printemps-été de blooms massifs de diatomées en chaîne et de grande taille. Depuis la découverte du mécanisme de fertilisation naturelle en fer sur le plateau, l'attention de la communauté scientifique s'est focalisée sur les diatomées de grande taille, qui favoriseraient la séquestration du carbone sur la zone. Toutefois, les données satellitaires suggéraient que le petit phytoplancton dominait les communautés phytoplanctoniques en dehors du bloom sur l'ensemble de la zone. Le premier objectif de ce travail visait à obtenir une image fine de la diversité du petit et grand phytoplancton après le bloom de diatomées (Mars 2018). Un fragment de l'ADNr 18S des communautés planctoniques de petite (0.2-20 µm) et grande taille (20-100 µm), collectées à plusieurs profondeurs, a été séquencé par la méthode Illumina MiSeq. Les séquences ainsi obtenues ont permis de déterminer la diversité taxonomique moléculaire du petit et grand phytoplancton. En surface, les diatomées étaient majoritaires dans la grande fraction de taille tandis que Phaeocystis antartica était particulièrement important dans la petite fraction sur l'ensemble de la zone d'étude. Dans leur ensemble, les communautés de petit phytoplancton différaient sur et en dehors du plateau. Des concentrations élevées en acide silicilique en dehors du plateau favorisaient la présence d'un assemblage varié de diatomées de petite taille, tandis que de fortes concentrations en ammonium sur le plateau pourraient favoriser le développement de picophytoplancton du genre Micromonas. L'utilisation de marqueurs pigmentaires chémotaxonomiques a permis de décrire la succession temporelle des communautés phytoplanctoniques sur le plateau, dominées par les diatomées du début au déclin du bloom, tandis que la contribution du petit phytoplancton augmentait fortement après le bloom (moins de 10% à 53% de la chlorophylle). Le deuxième objectif de cette thèse était d'établir la contribution relative de différents groupes phytoplanctoniques à la fixation globale de carbone, en prenant en compte les différences inter- et intra-groupe dans l'activité métabolique de cellules individuelles. Pour ce faire, des communautés planctoniques naturelles ont été incubées en présence d'un traceur isotopique (NaH¹³CO₃) en reproduisant les conditions in situ. La fixation du carbone au niveau cellulaire a été mesurée par imagerie NanoSIMS et SIMS. Les grandes diatomées (>20 µm) montraient des taux de croissance faibles et variables d'une cellule à l'autre, avec 19±13% de diatomées inactives. Inversement, les petites cellules, appartenant à des taxons phylogénétiques éloignés (prymnesiophytes, prasinophytes et petites diatomées) étaient majoritairement en croissance active (>98%). Par conséquent, le petit phytoplancton contribuait de 41 à 70% à la fixation du carbone sur l'ensemble de la zone après le bloom. Tandis que le petit phytoplancton contribuait de façon importante à la fixation de carbone et à la biomasse chlorophyllienne en surface, les diatomées dominaient dans les données pigmentaires et de séquençage en dessous de 200 m, indiquant leur export préférentiel par sédimentation directe. Cependant, un faisceau d'indices suggère que le phytoplancton de petite taille, en particulier Phaeocystis, pourrait participer à l'export de carbone par agrégation, ainsi que via les réseaux trophiques et la production de pelotes fécales des brouteursThis thesis focuses on small phytoplankton diversity (<20 µm) and its contribution to CO₂-fixation in contrasted marine ecosytems : the productive Kerguelen Plateau (KP) on the one hand and low productive surrounding waters on the other han. Iron-limited phytoplankton communities off-plateau are dominated by small cells all year long, whereas natural iron-fertilization over the KP promotes the seasonal development of chain-forming or large diatom blooms in spring and summer. Since the demonstration of natural iron fertilization on-plateau, the scientific community focused on large diatoms, assumed to promote carbon sequestration in the area. However, satellite data suggest that small phytoplankton dominate the phytoplankton communities outside of the bloom period on- and off-plateau. Consequently, this thesis had two main objectives. The first objective of this work was to obtain a precise image of the diversity of small and large phytoplankton after the diatom bloom (March 2018). A fragment of the 18S rRNA gene from small (0.2-20 µm) and large (20-100 µm) planktonic communities collected at discrete depths (down to 300 m), was sequenced (Illumina MiSeq) and used as an identity marker gene to determine the taxonomic diversity of small and large phytoplankton. At the surface, diatoms were dominant in the large-size fraction, while Phaeocystis antartica was particularly abundant in the small-size fraction, over the entire study area. As a whole, small phytoplankton communities were significantly different on- and off-plateau. High concentrations of silicic acid off-plateau favored the presence of a diverse assemblage of small diatoms, while high concentrations of ammonium on-plateau likely promoted the development of pico-sized Micromonas. Using chemotaxonomic pigments markers allowed the description of the temporal succession of phytoplankton communities on-plateau, dominated by diatoms from the onset to the decline of the bloom, while the contribution of small phytoplankton increased sharply after the bloom (less than 10% to 53% chlorophyll). The second objective of this thesis was to establish the relative contribution of different phytoplankton groups to bulk CO₂-fixation, considering inter- and intra-group differences in the metabolic activity if individual cells. To do so, natural planktonic communities were incubated mimicking in situ conditions in the presence of an isotopic tracer (NaH¹³CO₃). CO₂-fixation by small and large cells was then measured at the single cell level by NanoSIMS and SIMS imaging (mass spectrometry with lateral resolution of 50 nm and 1 µm, respectively). Large diatoms (> 20 µm) showed highly variable growth rates with 19±13 % inactive diatoms, whereas small cells, affiliated to distant phylogenetic taxa (prymnesiophytes, prasinophytes and small diatoms) were actively growing (>98%). This showed that small phytoplankton contributed to 41-70% of CO₂-fixation over the entire area after the bloom. While small phytoplankton contributed significantly to CO₂-fixation and chlorophyll biomass at the surface, diatoms dominated in pigment and sequencing data below 200 m, indicating their preferential export by direct sedimentation. However, a body of evidence suggests that small phytoplankton, in particular Phaeocystis, may contribute to carbon export through aggregation, as well as via the production of fecal pellets from grazers
37
Vale, Diego Wyllyam do. "Manejo da palha, adubação nitrogenada potássica e uso de inoculante em soca de cana-de-açúcar." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-23042013-100854/.
Анотація:
A colheita de cana-de-açúcar, sem despalha a fogo, vem crescendo no Brasil. Nesse sistema de cultivo, existem muitas dúvidas em relação ao manejo da palha, e das quantidades de nitrogênio e potássio a serem utilizadas. Objetivou-se avaliar o manejo da palha, adubação nitrogenada, potássica e uso do inoculante em área comercial de cana-de-açúcar. Para isso, instalou-se experimento na região de Piracicaba - SP, num Latossolo Vermelho Amarelo Distrófico, cultivado com a variedade de cana-de-açúcar CTC 9, em delineamento de blocos casualizados em esquema fatorial incompleto 3x6x4, totalizando 153 parcelas, sendo três manejos da palha-MP (distribuição da palha da cana em toda área-MPT, retirada da palha apenas nas linhas da cana-de-açúcar-MPRL e enleiramento da palha a cada duas linhas-MP2:1), seis doses de N (aplicação de 0, 60, 120 e 180 kg ha-1 de N, aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio na ausência de adubação nitrogenada e aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio mais 30 kg ha-1 de N mineral), quatro doses de K (0, 50, 100 e 150 kg de K2O ha-1) e três repetições. As variáveis analisadas ao longo das duas socas foram: análises químicas do solo, emissão de CO2, diagnose foliar, avaliações biológicas e tecnológicas e produção de colmos da cana-de-açúcar. A aplicação de nitrogênio e potássio afetou a fertilidade do solo, teor foliar de N, açúcar teórico recuperável e crescimento da cana-de-açúcar. A aplicação de 80 kg ha-1 de K2O é suficiente para apresentar alta produtividade da primeira (87 t ha-1) e da segunda soca de cana-deaçúcar (141 t ha-1) e não houve resposta a aplicação de nitrogênio mineral. A aplicação de inoculante não aumentou a produtividade da cana-de-açúcar. O MPRL se mostrou como o mais promissor em relação ao crescimento e produtividade da cana-de-açúcar. O MPRL apresentou maior emissão de carbono se comparado ao MP2:1 na 2a soca. Na 1ª soca, no MPT, MPRL e MP2:1, a emissão de CO2 foi de 1,7; 2,0 e 1,7 ?mol m-2 s-1, a temperatura foi de 21,7; 21,7; 21,2 ºC e a umidade foi de 11,1; 6,6 e 9,5%, respectivamente. Na 2ª soca, no MPT, MPRL e MP2:1, o CO2 foi de 1,8; 2,1 e 1,6 ?mol m-2 s-1, a temperatura foi de 21,4; 22,9; 22,4 ºC e a umidade foi de 16,9; 12,3 e 11,5%, respectivamente. A emissão de CO2 aumentou com o crescimento das plantas de cana-de-açúcar e oscilou de 6 a 12,4 ?mol m-2.The harvesting of sugarcane, straw removal without fire, is growing in Brazil. In this culture system, there are many questions about the management of residue, and the amounts of nitrogen and potassium to be used. This study aimed to evaluate the straw management sugarcane, nitrogen, potassium and use of inoculants in commercial sugarcane. For this experiment was installed in Piracicaba - SP, in the Oxissol cultivated with the variety of sugarcane CTC 9, in a randomized block design in a incomplete factorial 3x6x4, totaling 153 plots, three management of stubble-MP (distribution of sugarcane trash in every area-MPT, removal of straw only rows of sugarcane MPRL and windrowing straw every two lines-MP2:1) six doses of N (application of 0, 60, 120 and 180 kg ha-1 of N, applied in line with the cane solution containing five species of nitrogen-fixing bacteria in the absence of nitrogen fertilizer application on line and cane solution containing five species of nitrogen-fixing bacteria plus 30 kg ha-1 of mineral N), four doses of K (0, 50 , 100 and 150 kg ha-1 of K2O) and three replications. The variables analyzed along the two years were: soil chemical analysis, CO2 emission, foliar diagnosis, biological and technological evaluations and straw yield of sugarcane. The application of nitrogen and potassium affect soil fertility, leaf N content, theoretical recoverable sugar and growth of sugarcane. The application of 80 kg ha-1 of K2O is sufficient to present the first high productivity (87 t ha-1) and second ratoon sugarcane (141 t ha-1) and there was no response from the application nitrogen mineral. The inoculant application did not increase productivity of sugarcane. The MPRL proved as the most promising in relation to growth and productivity of sugarcane. The MPRL had lower moisture and higher carbon footprint compared to MPT and MP2:1. In the 1st ratoon, the MPT, MPRL and MP2:1, the emission of CO2 was 1.7, 2.0 and 1.7 ?mol m-2 s-1, the temperature was 21.7, 21.7; 21.2 ºC and humidity was 11.1, 6.6 and 9.5%, respectively. In the 2nd ratoon in MPT, MPRL and MP2:1 first, the CO2 was 1.8, 2.1 and 1.6 ?mol m-2 s-1, the temperature was 21.4, 22.9; 22, 4 ºC and the humidity was 16.9, 12.3 and 11.5%, respectively. The emission of CO2 increased with the growth of plants sugarcane and oscillated 6 to 12.4 ?mol m-2 s-1.
38
Zhang, Kun. "Fumaric Acid Fermentation by Rhizopus oryzae with Integrated Separation Technologies." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354729467.
39
Wright, K. M. "The influence of ammonia on photosynthetic and dark CO2̲ fixation in higher plants." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379318.
40
Lenoir, Guillaume. "Etude des changements de conformation de l'ATPase-Ca2+ du réticulum sarcoplasmique (SERCA1) associés à la fixation et au transport de Ca2+." Paris 11, 2004. http://www.theses.fr/2004PA11TO14.
41
Kreibich, Julian. "Mechanistic insights into carbon monoxide and CoA binding at the Ni,Ni-[4Fe-4S] active site of the acetyl-CoA synthase from Carboxydothermus hydrogenoformans." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/23215.
Анотація:
Die Acetyl-CoA Synthase (ACS) beinhaltet ein einzigartiges Metallcluster (Cluster A) in seinem aktiven Zentrum, welches wichtig für ein autotrophes Wachstum von Bakterien und Archaeen ist, die den reduktiven Acetyl-CoA-Weg nutzen. Der letzte Schritt dieses Syntheseweges wird von der ACS am proximal zum [4Fe-4S] Cluster liegenden Ni ion katalysiert (Nip). In meiner Arbeit wurde die ACS von Carboxydothermus hydrogenoformans (ACSCh) auf seine Ligandenbindung untersucht und in verschiedenen Konformationen kristallisiert.
Zuerst wurde die ACSCh in einer neuen Konformation (ACSCh-closed) kristallisiert und deren Struktur mit einer Auflösung von 2.1 Å bestimmt. Diese wies einen geringeren Kontakt zur Solventumgebung auf als die vorher bekannte Struktur der ACSCh (ACSCh-open, PDB-ID: 1RU3). Das Cluster A der ACSCh-closed unterscheidet sich von der ACSCh-open in der Koordination des Nip, welches verzerrt tetraedrisch koordiniert in ACSCh-closed vorliegt und quadratisch planar in ACSCh-open. Eine Analyse des Modells wies einen molekularen Tunnel auf, der nur in ACSCh-closed vorhanden ist, welcher als CO-Kanal zur Substratversorgung dienen könnte.
Zweitens wurde die Kristallstruktur einer CO gebunden ACSCh-closed mit einer Auflösung von 2.0 Å gelöst. Darin wurde eine Elektronendichte am Nip identifiziert, die als CO überzeugend modelliert werden konnte. CO bindet am ebenfalls verzerrt tetraedrisch koordinierten Nip. Die Konformationsänderung von ACSCh-open zu ACSCh-closed scheint der entscheidende Schritt zu sein, um CO zur Bindungsstelle zu leiten.
Die dritte Struktur zeigt eine CoA gebundene ACSCh Struktur mit einer Auflösung von 2.3 Å. CoA bindet am Nip, wobei Nip quadratisch planar koordiniert wird. Die Gegenwart von CoA wurde mit Berechnungen verschiedener Elektronendichte-Karten für CoA validiert.
Die Bindung von CO und CoA an ACSCh wurde zudem mittels isothermaler Titrationskalorimetrie weiter charakterisiert. Dabei bindet CoA enthalpisch getrieben mit einem KD von 3.1 µM und CO entropisch getrieben mit einem KD von 9.4 µM an ACSCh.The acetyl-CoA synthase (ACS) harbors a unique metal cluster (cluster A) in its active site, which is important for bacteria and archaea to survive in autotrophic growth using the reductive acetyl-CoA. The last step of this pathway is catalyzed by ACS at the Nip, the Ni ion proximal to the [4Fe-4S] cluster. In my study, the monomeric ACS of Carboxydothermus hydrogenoformans (ACSCh) was studied in its ligand binding and crystallized in different forms. At first, an ACSCh structure was solved in a new conformation at dmin of 2.1 Å and less solvent exposed (called ACSCh-closed) than the known structure of ACSCh (called ACSCh-open, PDB-ID:1RU3). The cluster A of ACSCh-closed differs to that of ACSCh-open in the coordination of the proximal Ni, which is distorted tetrahedrally coordinated in ACSCh-closed and square planar coordinated in ACSCh-open. Analysis of the model revealed a molecular tunnel that is only present in ACSCh-closed, which might act as CO channel for substrate delivery. Secondly, a CO-bound ACSCh-closed crystal was obtained and solved at a resolution of 2.0 Å. An electron density fitting with a diatomic ligand at the Nip site was clearly identified and modeled as a CO molecule. CO binds at the Nip site completing the tetrahedral coordination geometry of Nip. The conformational switch between open and closed is responsible for CO migration and binding to the catalytic site. A third crystal structure depicts a CoA bound ACSCh structure at 2.3 Å resolution. CoA binds at the Nip which shows a square planar geometry. This was further supported by calculating different electron density maps for CoA. The binding of CO and CoA to ACSCh has been characterized by isothermal calorimetry experiments. While CoA binding is enthalpically driven with a KD of 3.1 µM, CO binds to ACSCh by entropic contribution with a KD of 9.4 µM.
42
Leroy, Didier. "Interaction polyamines/protéine-kinase CK2 : étude moléculaire et fonctionnelle." Grenoble 1, 1996. http://www.theses.fr/1996GRE10046.
Анотація:
La proteine-kinase ck2 est une serine/threonine proteine-kinase ubiquiste dans le monde eucaryote. Elle se compose de deux sous-unites catalytiques differentes alpha et alpha' et d'une sous-unite regulatrice beta qui s'assemblent sous la forme d'heterotetrameres. La ck2 utilise l'atp comme le gtp, phosphoryle des proteines et peptides substrats acides et necessite une concentration extraphysiologique d'ions magnesiums pour pouvoir exhiber son activite catalytique maximale. Bien que plusieurs evidences suggerent qu'in vivo, la ck2 joue un role indispensable, aucun mode de regulation cellulaire n'a pu etre propose pour cette kinase a l'heure actuelle. Parmi les candidats susceptibles de porter une telle fonction regulatrice, les polyamines sont des composes vis-a-vis desquels de nombreuses etudes ont ete realisees. Presentes en concentrations submillimolaires, ces molecules sont capables de stimuler l'activite catalytique de la ck2 d'un facteur 10 a 20 dans des conditions de concentrations physiologiques d'ions magnesiums. Lors de ces travaux, les parametres cinetiques regissant l'activation de la ck2 en presence de polyamines, ont ete definis. L'effet de la spermine sur la ck2 a ete analyse par dichroisme circulaire. L'interaction spermine-ck2 a ete caracterisee en presence de molecules analogues de la spermine ainsi qu'en ce qui concerne le type et le nombre de liaisons mises en jeu. L'utilisation d'un analogue photoactivable de la spermine a permis d'identifier un site majeur de liaison des polyamines sur la sous-unite beta au niveau du peptide t72-m78. Deux autres sites ont ete detectes au niveau des residus h108 de cette sous-unite et l220 de la sous-unite alpha. La construction, l'expression et la purification de proteines de fusion impliquant le domaine d51-p110 de la sous-unite beta ou la sous-unite beta entiere ont permis de confirmer les resultats du marquage de photoaffinite d'une part et de definir ce domaine comme autonome et fonctionnel d'autre part. Son utilisation a conduit entre autre a la mise en evidence des domaines impliques dans l'interaction des proteines fgf-2 et ck2. Aujourd'hui, la poursuite de ce travail par une approche cellulaire pourrait permettre d'apporter des elements de reponse quant a l'existence d'un role de regulateurs physiologiques joue par les polyamines vis-a-vis de la ck2
43
GOMES, Antonio Aristófanes da Cruz. "Desenvolvimento de uma placa de fixação óssea utilizando liga com memória de forma Ni-Ti." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1922.
Анотація:
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CNPq
Os procedimentos cirúrgicos de reconstrução crânio facial vêm se desenvolvendo significativamente e grande parte desse progresso se deve às inovações nas técnicas cirúrgicas e ao emprego de novos materiais na fabricação dos dispositivos de fixação. O objetivo principal é tornar os procedimentos mais eficientes e menos invasivos aos pacientes, consequentemente haverá diminuição nos índices de retrabalhos. O emprego de Ligas com Memória de Forma (LMF) pode ser uma alternativa interessante nesses casos, uma vez que esses materiais possuem um comportamento adaptativo, com a capacidade de reagir a estímulos externos de natureza térmica ou mecânica. As LMF da família Ni-Ti lideram o interesse das pesquisas devido ao maior número de aplicações comerciais, principalmente nas áreas médica e odontológica. Essas LMF Ni-Ti, além de serem biocompatíveis possuem também módulo de elasticidade inferior ao de ligas de titânio, como o Ti-Al-V, e dos aços inoxidáveis. Neste contexto, o objetivo deste trabalho é desenvolver um protótipo de placa de fixação óssea, que poderá ser destinada a procedimentos de trauma e reconstrução mandibular, utilizando uma LMF Ni-Ti com características superelásticas. Foi escolhido um elemento de fixação, tipo placa, como modelo para os protótipos e as dimensões foram baseadas em componentes fornecidos comercialmente. Para a fabricação dos dispositivos optou-se pelos processos de fundição de precisão: Plasma Skull Push-Pull (PSPP), e fusão por indução com injeção por centrifugação (FIC), os quais se mostraram bastante eficazes. Foram realizados ensaios de caracterização para determinar as propriedades térmicas e mecânicas do dispositivo fabricado. Os principais resultados foram um componente de rigidez variável com a temperatura, módulo de elasticidade da ordem de 50 GPa na temperatura corpórea e vida em fadiga ente 103 e 106 para amplitudes de deslocamento em flexão entre 0,5 mm e 2,5 mm. Estes resultados de caracterização termomecânica indicam o potencial das LMF Ni-Ti e dos processos de fundição de precisão para a produção de placas de fixação óssea.
Surgical procedures for facial skull reconstruction have been developing significantly and much of this progress is due to innovations in surgical techniques and the use of new materials in the manufacture of fastening devices. The main objective is to make the procedures more efficient and less invasive to the patients, consequently there will be a decrease in the rates of reworking. The use of Shape Memory Alloys (SMA) may be an interesting alternative in these cases, since these materials have an adaptive behavior, with the ability to react to external stimuli of a thermal or mechanical nature. The SMA of the Ni-Ti family lead the research interest due to the greater number of commercial applications, mainly in the medical and dental areas. In addition to being biocompatible, these Ni-Ti SMAs also have lower modulus of elasticity than titanium alloys, such as Ti-Al-V, and stainless steels. In this context, the objective of this work is to develop a prototype bone fixation plate, which can be used for trauma and mandibular reconstruction procedures, using a Ni-Ti SMA with superelastic characteristics. A plate-type fastening element was chosen as the prototype model and the dimensions were based on commercially supplied components. In order to manufacture the devices, it was chosen the precision casting processes: Plasma Skull Push-Pull (PSPP) and induction fusion with centrifugal injection (FCI), which proved to be quite effective. Characterization tests were performed to determine the thermal and mechanical properties of the fabricated device. The main results were a variable stiffness component with temperature, modulus of elasticity of the order of 50 GPa at body temperature and fatigue life between 103 and 106 for flexural displacement amplitudes between 0.5 mm and 2.5 mm. These thermomechanical characterization results indicate the potential of Ni-Ti SMA and precision casting processes for the production of bone fixation plates.
44
Galindo, Fernando Shintate. "Inoculation with Azospirillum brasilense associated with silicon applied to correct soil acidity and nitrogen rates in corn and wheat crops /." Ilha Solteira, 2020. http://hdl.handle.net/11449/192642.
Анотація:
Orientador: Marcelo Carvalho Minhoto Teixeira FilhoResumo: Alternative management practices are needed to minimize the need for chemical fertilizer use in non-leguminous cropping systems. The use of biological agents which can fix atmospheric nitrogen and promote plant growth has shown potential as an option to improve soil nutrient availability to grass crops. In recent years, studies investigating the effects of silicon (Si) have increased substantially, especially in grain crops. This increased interest in Si is likely due to the beneficial effects of Si application on plant resistance to abiotic and biotic stresses, reflecting on greater plant development. This research was developed to investigate if inoculation of corn and wheat with Azospirillum brasilense associated with Si can enhance nitrogen use efficiency (NUE) and improve plant nutrition and yield, leading to a greater economic profit. The study was set up in a Rhodic Haplustox under no-till system, located in Selvíria, state of Mato Grosso do Sul, Brazil. The field trial took place during the 2015/16 (November-March), 2016 (April-September), 2016/17 (November-March) and 2017 April-September) seasons, with corn and wheat crops in sucession (spring/summer and winter seasons for corn and wheat, respectively). Treatments were tested in a randomized completely block design with four replicates, arranged in a full factorial design 5 × 2 × 2 and included: i) five N application rates, as urea source, applied in side-dressing (0, 50, 100, 150 and 200 kg ha-1); ii) two liming sou... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
45
YANG, REN-HONG, and 楊仁宏. "A study of fixation CO2 in microalgae." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/59825239928406294633.
Анотація:
碩士明新科技大學
土木工程與環境資源管理系碩士班
101
Abstract In recent years, the amount of CO2 emissions are causing global warming, CO2 immobilization technology can’t be ignored. In Taiwan, various CO2 reduction method, the use of algae fixed CO2 reduce the co2 pollution problems, and solid carbon frond resource, and therefore deemed to be one of the economic efficiency of the method. In this study, chlorella as the main object, discussion chlorella in a different growth factor, carbon sequestration efficiency and growth rate differences, by different inoculation concentration, temperature and light intensity, to identify the most suitable free environment for the growth and the best efficiency of carbon sequestration. The experimental results show a linear relationship, the relationship between chlorophyll and algae dry weight, using the calibration curve can be calculated by the chlorophyll content of the algae dry weight calibration curve R2 = 0.998 accurately a very high degree. Also found that chlorella carbon fixation rate, not due to the different from inoculum concentration, another light intensity is too high or the temperature is too low will result in chlorella Yang system growth, ball algae growth and carbon fixation rate is quite obvious, chlorella growth in the range of an environment conducive to the growth and carbon fixation rate and growth rate will be greatly enhanced. A 30℃ environment to 4000 LUX continuous irradiation 24 hours and the initial water quality the best growth efficiency and carbon fixation rate was adjusted to pH = 6.0 can be achieved, in water 404.1 mg / L of carbon dioxide via the 5-day training will be depleted, and the chlorella cell concentration can be achieved 102.013 mg / L, the growth rate of 0.513 d-1.
46
Flowers, Brendan John Scott. "CO2 fixation : catalytic synthesis of β-hydroxycarboxylic acids". Thesis, 2008. http://hdl.handle.net/1974/1368.
Анотація:
Although carbon dioxide as a greenhouse gas is a serious environmental concern, it remains a valuable C1 source if viable methods are available for its conversion into useful products. Herein, we present recent progress in the synthesis of aliphatic, aromatic, cyclic, and bicyclic beta-ketocarboxylic acids and the promising results from subsequent asymmetric hydrogenation to give beta-hydroxycarboxylic acids.
For the synthesis of the beta-ketocarboxylic acids, we investigated the effects of temperature, reaction time, and amount of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), which is a promoter for carbon-carbon bond formation with CO2. The highest-yielding conditions for this DBU-promoted carboxylation reaction were used to carboxylate a number of aliphatic and aromatic substrates.
In order to determine whether the hydrogenation reaction will effectively compete with the in situ decarboxylation of the beta-ketocarboxylic acids, 1H NMR spectroscopy was used to monitor the rate of decarboxylation. The solvent, electronic, and steric effect on the rate of decarboxylation was investigated by testing a variety of beta-ketocarboxylic acids.
Using RuCl2{(S)-BINAP} catalyst precursor, we determined the effect that solvent, H2 pressure, base, and substrate substitution had on the enantioselectivity of the asymmetric hydrogenation. CH2Cl2 and MeOH were determined to be the best solvents because of the high hydrogenation selectivity, high enantioselectivity, and decreased reaction times. These standard conditions were used to hydrogenate the variety of aliphatic and aromatic beta-ketocarboxylic acids previously synthesized.
Additional experiments, including deuterium labelling, were performed in an attempt to elucidate the hydrogenation mechanism and the actively hydrogenated tautomer. These results lead us to believe that different reaction pathways occur in protic versus aprotic solvents.
The results discussed herein represent the first in depth investigation of transition metal catalyzed hydrogenation of beta-ketocarboxylic acids. These results are very encouraging because enantioselectivities greater than 99 % were achieved for multiple beta-keto acids. This synthesis is industrially advantageous due to the limited number of reactants required, their low-cost, and the potential for recycling unused materials.Thesis (Master, Chemistry) -- Queen's University, 2008-08-26 10:17:34.703
47
Graham, Amanda. "NITROGEN FIXATION AND THE FATE AND TURNOVER OF CARBON FIXED THROUGH HYDROGEN-COUPLED CARBON DIOXIDE FIXATION IN SOYBEANS." Thesis, 2013. http://hdl.handle.net/1974/7785.
Анотація:
Global production of soybeans continues to increase, reflecting the value of soybeans in food products, soil amendments, and petroleum replacements. While the N2O aspect of the legume greenhouse gas (GHG) budget has been given substantial, and mostly negative, attention, the CO2 side needs to be explored. During nitrogen fixation, hydrogen is produced. As a result of hydrogen-coupled CO2 fixation, legume soils have the ability to increase the amount of atmospheric carbon fixed into the soil. However, the amount and fate of this fixed carbon has yet to be determined. Therefore, two experiments were conducted. The first experiment explored the methods of 13C labeling of four soil treatments over a period of 28 days. Results showed that most of this carbon uptake was through biotic processes, and that the pattern of carbon uptake was similar for all four soil treatments. The ideal labeling time for both ‘root’ and ‘nodule’ soil was determined to be between 7 and 14 days. The second experiment incubated four 13C labeled soil treatments in a continuous soybean field for 11 months. Throughout this time, bags of soil were removed and separated into three soil organic matter (SOM) fractions; the microbial biomass fraction (MBF), the light fraction (LF), and the acid stable fraction (ASF). These fractions were then measured for δ13C, providing a time series showing carbon movement through the soil which enabled an estimation of the MRT of fixed carbon in the soil. Results showed that the MBF was responsible for the initial flux of carbon uptake in all soil treatments, and that the ‘nodule + H2’ MBF continued to fix carbon at the end of the 11 months. While the LF was not ideal at representing the intermediate SOM pool, the ASF did increase in enrichment at the end of the experiment, showing the movement of newly fixed carbon into long-term carbon storage. Therefore, hydrogen-coupled CO2 fixation does contribute to long-term carbon storage in legume soils, however, longer study times with focus on different legume plants and soil types are required to determine the mean residence time (MRT) of fixed carbon in the ASF.Thesis (Master, Geography) -- Queen's University, 2013-01-30 09:28:01.899
48
Peng, Yu-Hua, and 彭于華. "Study on the Growth Conditions for Fresh Water Microalgae CO2 Fixation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/30878838799825275890.
Анотація:
碩士國立屏東科技大學
環境工程與科學系所
97
Industrial development consume huge amount of coal, petroleum, natural gas and release massive amount of greenhouse gases. Couple with population growth and forests cutting, greenhouse gases cause global warming and many climate change induced disasters recently. After realized these not-natural disasters will origin large-scale ecosystem broken, human life threaten, and economy crash, The United Nations had drawn up The United Nation Framework Convention on Climate Change and Kypto Protocol to limit greenhouse gases emission. This study is also trying to do the effort on global warming issue. We like to find out the best growth condition for freshwater microalgae CO2 fixation in South Taiwan. Chlorella vulgari collected from pound in NPUST was selected as material. The M4N medium used to supply essential nutrients for microalgae growth. Six parameters were choose to exam microalgae growth rate which were: algae injecting concentration (329 mg/L、522 mg/L、648 mg/L and 770 mg/L); temperature (15, 25 and 35℃); CO2 concentration (5, 10, 15 and 20 %); light cycles (night/day) (12 and 24 hours); pH value (5, 6, 7 and 8); and light source (plant lamp, fluorescent tubes, and LED red lamp). The culture cycle was incubated in a growth chamber for 15 days. Spectrophotometer was used to measured growth curve at wavelength 680nm. In summary, the maximum biomass and CO2 fixation rate was at the condition that solution pH = 7.0, 24 hours lighting by fluorescent tubes, 10% CO2 injected, 35℃, and the initial Chlorella vulgaris concentration was 522mg / L. Under these conditions we could get 4,659 mg/L of microalgae biomass and 5,594 mgCO2/L of CO2 fixation.
49
Chen, Shin-Yi, and 陳欣億. "The Study of CO2 Fixation on The Magnesium-Lithium Mixed Metal Complexes." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/44540240620332177603.
Анотація:
碩士國立中山大學
化學系研究所
91
The reaction of Mg(NPh2)2 with LiNR2 (R= SiMe3, NiPr, NiBu) generated the same product, [Mg(NPh2)3(THF)][Li(THF)4] which was identified by 1H-NMR and X-ray crystallography. The magnesium-lithium mixed metal complex reacted with excess carbon dioxide in the ice bath to generate the tetralithium complex, Li4(O2CNPh2)4(THF)4 which was identified by 1H-NMR, 13C-NMR, IR, and X-ray crystallography.
50
Chen, Kuan-Wei, and 陳冠薇. "Carbonation of Steel-making Slag for CO2 Fixation and Utilization in Blended Cement." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/36475952635977735426.
Анотація:
碩士國立臺灣大學
環境工程學研究所
103
This study explores the feasibility of developing sustainable construction materials via mineral carbonation of steelmaking slag, i.e., basic oxygen furnace slag (BOFS). The carbon fixation capacity of BOFS was quantified by thermo-gravimetric analysis. Various engineering properties and hydration characteristics of blended cement with 10 % of both fresh BOFS and carbonated BOFS by weight as cement replacement was investigated. The results indicate mineral carbonations accompanied by significant reduction in basicity and fixing 0.202 and 0.221 kg CO2/kg BOFS at 30 oC and 60 oC within the rotating packed bed (RPB) reactor. The reaction kinetics of carbonation experiments could be well expressed by the surface coverage model, with R2 values ranged from 0.97 to 0.98. Cement blended with 10 wt% of carbonated BOFS resulted in reduced setting times and accelerated early strength development, which was consistent with the results of hydration heat and XRD observations. The SEM observations suggest that the carbonated BOFS could serve as nuclei for the precipitation of hydration products, while also accelerating the hydration. In addition, blended cement with 10 % of carbonated BOFS improved sulfate resistance ability and drying shrinkage property compared to 10 % of fresh BOFS at ambient temperature (23oC). The mineralogical composition changes after carbonation have beneficial effects on the hydraulic property in concrete. It was thus concluded that the carbonation of steelmaking slag should be considered as a feasible and attractive process for carbon fixation and waste valorization