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Artigos de revistas sobre o assunto "Culture heterotrophe"
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Wang, Jing Han, Hai Zhen Yang e Feng Wang. "Potential of Mixotrophic Cultivation of Chlorella sorokiniana for Biodiesel Production". Advanced Materials Research 779-780 (setembro de 2013): 1509–13. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1509.
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Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgal biodiesel can be produced under three major cultivation modes, namely, photoautotrophic, heterotrophic, and mixotrophic cultivation. Studies of biodiesel production from microalgae have been reported mostly focusing on photoautotrophic cultivation, mixotrophic cultivation has rarely been researched. This paper compared the biomass productivity, lipid content, and lipid productivity ofChlorella sorokinianaunder photoautotrophic, heterotrophic, and mixotrophic cultivation. Glucose was adopted as organic carbon source at five concentrations (0.1, 0.5, 1.0, 2.0, 5.0% glucose w/v). Results displayed that microalgal growth was significantly improved in glucose supplied cultures. Synergetic effect of photoautotrophy and heterotrophy existed in mixotrophic cultivation except for 5.0% culture. Highest biomass productivity of 1.178 g·L-1·d-1and highest lipid productivity of 582 mg·L-1·d-1was observed under mixotrophic cultivation with 2.0% (w/v) glucose addition. Lipid content ofC. sorokinianawas mostly higher in stationary phase than in exponential phase. Highest lipid content of 49.37% was observed in 2.0% mixotrophic culture, followed by 47.09% in 2.0% heterotrophic culture.
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Wang, Jing Han, Hai Zhen Yang e Feng Wang. "Mixotrophic Cultivation of Scenedesmus sp. as Biodiesel Feedstock". Advanced Materials Research 777 (setembro de 2013): 268–73. http://dx.doi.org/10.4028/www.scientific.net/amr.777.268.
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Microalgae are a promising feedstock for biodiesel production. Microalgal biodiesel can be obtained under three major cultivation modes, namely, photoautotrophic, heterotrophic, and mixotrophic cultivation. Reported studies of microalgal biodiesel production are mainly based on photoautotrophic cultivation, mixotrophic cultivation has rarely been researched. This paper compared the biomass productivity, lipid content, and lipid productivity of Scenedesmus sp. under photoautotrophic, heterotrophic, and mixotrophic cultivation. Glucose was added as organic carbon source at five concentrations (0.1, 0.5, 1.0, 2.0, 5.0% glucose w/v). Results displayed that microalgal growth was significantly improved in glucose supplied cultures. Synergetic effect of photoautotrophy and heterotrophy existed in all mixotrophic cultures. Highest biomass productivity of 1.307 g·L-1·d-1 and highest lipid productivity of 316 mg·L-1·d-1 was respectively observed under mixotrophic cultivation with 5.0% and 1.0% (w/v) glucose addition. Lipid content of Scenedesmus sp. under mixotrophic cultivation was mostly higher in stationary phase than in exponential phase. Highest lipid content of 27.73% was observed in 1.0% mixotrophic culture, followed by 24.66% in 1.0% heterotrophic culture.
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Correia, Nádia, Hugo Pereira, Peter S. C. Schulze, Monya M. Costa, Gonçalo E. Santo, Inês Guerra, Mafalda Trovão et al. "Heterotrophic and Photoautotrophic Media Optimization Using Response Surface Methodology for the Novel Microalga Chlorococcum amblystomatis". Applied Sciences 13, n.º 4 (6 de fevereiro de 2023): 2089. http://dx.doi.org/10.3390/app13042089.
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The nutritional requirements of novel microalgal strains are key for their effective cultivation and metabolite content. Therefore, the optimization of heterotrophic and photoautotrophic culture media is crucial for novel Chlorococcum amblystomatis growth. Heterotrophic and photoautotrophic biomass samples were characterized to identify the differences between their heterotrophic and photoautotrophic biomass composition and their biotechnological potential. Media optimization through surface response methodology led to 44.9 and 51.2% increments in C. amblystomatis-specific growth rates under heterotrophic and photoautotrophic growth, respectively. This microalga registered high protein content (61.49–73.45% dry weight), with the highest value being observed in the optimized photoautotrophic growth medium. The lipid fraction mainly constituted polyunsaturated fatty acids, ranging from 44.47 to 51.41% for total fatty acids (TFA) in cells under heterotrophy. However, these contents became significantly higher (70.46–72.82% TFA) in cultures cultivated under photoautotrophy. An interesting carotenoids content was achieved in the cultures grown in optimized photoautotrophic medium: 5.84 mg·g−1 β-carotene, 5.27 mg·g−1 lutein, 3.66 mg·g−1 neoxanthin, and 0.75 mg·g−1 violaxanthin. Therefore, C. amblystomatis demonstrated an interesting growth performance and nutritional profile for food supplements and feed products that might contribute to meeting the world’s nutritional demand.
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Park, Jeong-Eun, Shan Zhang, Thi Hiep Han e Sun-Jin Hwang. "The Contribution Ratio of Autotrophic and Heterotrophic Metabolism during a Mixotrophic Culture of Chlorella sorokiniana". International Journal of Environmental Research and Public Health 18, n.º 3 (2 de fevereiro de 2021): 1353. http://dx.doi.org/10.3390/ijerph18031353.
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The contribution ratio of autotrophic and heterotrophic metabolism in the mixotrophic culture of Chlorella sorokiniana (C. sorokiniana) was investigated. At the early stage of mixotrophic growth (day 0–1), autotrophy contributed over 70% of the total metabolism; however, heterotrophy contributed more than autotrophy after day 1 due to the rapid increase in cell density, which had a shading effect in the photo-bioreactor. Heterotrophy continued to have a higher contribution until the available organic carbon was depleted at which point autotrophy became dominant again. Overall, the increase in algal biomass and light conditions in the photo-bioreactor are important factors in determining the contribution of autotrophy and heterotrophy during a mixotrophic culture.
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Cupo, Adelaide, Simone Landi, Salvatore Morra, Genoveffa Nuzzo, Carmela Gallo, Emiliano Manzo, Angelo Fontana e Giuliana d’Ippolito. "Autotrophic vs. Heterotrophic Cultivation of the Marine Diatom Cyclotella cryptica for EPA Production". Marine Drugs 19, n.º 7 (23 de junho de 2021): 355. http://dx.doi.org/10.3390/md19070355.
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Recently, the marketable value of ω-3 fatty acid, particularly eicosapentaenoic acid (EPA), increased considering their health effects for human consumption. Microalgae are considered a valuable and “green” source of EPA alternative to fish oils, but considerable efforts are necessary for their exploitation at an industrial level. Due to the high operation costs of photoautotrophic microalgae cultivation, heterotrophic growth represents a promising economic solution. Marine diatoms are the major ecological producers of ω-3 fatty acids. Few species of diatoms are capable to grow in the dark using organic carbon sources. The marine diatom Cyclotella cryptica was cultivated for 14 days under photoautotrophic and heterotrophic conditions to define the effects on growth parameters, lipid production, total fatty acids and EPA content. Photoautotrophic conditions led to a total EPA production of 1.6% of dry weight, 12.2 mg L−1 culture and productivity of 0.9 mg L−1 day−1. The heterotrophy cultures reported a total EPA production of 2.7% of dry cell weight, 18 mg L−1 culture, a productivity of 1.3 mg L−1 day−1, which are promising values in the prospective of improving culture parameters for the biotechnological exploitation of dark cultivation. C. cryptica could be a potential candidate for the heterotrophic production of EPA, also considering its robustness, capacity to resist to bacterial contaminations and plasticity of lipid metabolism.
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Wang, Kaixuan, Zhongjie Wang, Yi Ding, Youzhi Yu, Yali Wang, Yahong Geng, Yeguang Li e Xiaobin Wen. "Optimization of Heterotrophic Culture Conditions for the Algae Graesiella emersonii WBG-1 to Produce Proteins". Plants 12, n.º 12 (9 de junho de 2023): 2255. http://dx.doi.org/10.3390/plants12122255.
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The aim of this study was to improve the protein content and yield of heterotrophic microalgal cultivation and establish a simple, economical, and efficient method for microalgal protein production using the novel green alga, Graesiella emersonii WBG-1, which has not been previously reported for heterotrophic cultivation. Through batch heterotrophic cultivation of this alga, we observed that glucose was the optimal carbon source, while it could not use sucrose as a carbon source. Biomass production and protein content were significantly reduced when sodium acetate was used as the carbon source. Compared with nitrate, protein content increased by 93% when urea was used as the nitrogen source. Cultivation temperature had a significant impact on biomass production and protein content. The optimal conditions were glucose as the carbon source at an initial concentration of 10 g/L, urea as the nitrogen source at an initial concentration of 1.62 g/L, and a culture temperature of 35 °C. On the second day of batch cultivation, the highest protein content (66.14%) was achieved, which was significantly higher than that reported in heterotrophic cultures of Chlorella and much higher than that reported for specially established technologies aimed at increasing the protein content, such as two-stage heterotrophic, heterotrophy–dilution–photoinduction, and mixotrophic processes. These results demonstrate the great potential of the heterotrophic cultivation of G. emersonii WBG-1 for protein production.
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Morris, J. Jeffrey, Robin Kirkegaard, Martin J. Szul, Zackary I. Johnson e Erik R. Zinser. "Facilitation of Robust Growth of Prochlorococcus Colonies and Dilute Liquid Cultures by “Helper” Heterotrophic Bacteria". Applied and Environmental Microbiology 74, n.º 14 (23 de maio de 2008): 4530–34. http://dx.doi.org/10.1128/aem.02479-07.
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ABSTRACT Axenic (pure) cultures of marine unicellular cyanobacteria of the Prochlorococcus genus grow efficiently only if the inoculation concentration is large; colonies form on semisolid medium at low efficiencies. In this work, we describe a novel method for growing Prochlorococcus colonies on semisolid agar that improves the level of recovery to approximately 100%. Prochlorococcus grows robustly at low cell concentrations, in liquid or on solid medium, when cocultured with marine heterotrophic bacteria. Once the Prochlorococcus cell concentration surpasses a critical threshold, the “helper” heterotrophs can be eliminated with antibiotics to produce axenic cultures. Our preliminary evidence suggests that one mechanism by which the heterotrophs help Prochlorococcus is the reduction of oxidative stress.
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Hršak, Dubravka, e Ana Begonja. "Possible Interactions within a Methanotrophic-Heterotrophic Groundwater Community Able To Transform Linear Alkylbenzenesulfonates". Applied and Environmental Microbiology 66, n.º 10 (1 de outubro de 2000): 4433–39. http://dx.doi.org/10.1128/aem.66.10.4433-4439.2000.
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ABSTRACT The relationships and interactions within a methanotrophic-heterotrophic groundwater community were studied in a closed system (shake culture) in the presence of methane as the primary carbon and energy source and with the addition of the pure linear alkylbenzenesulfonate (LAS) congener 2-[4-(sulfophenyl)]decan as a cometabolic substrate. When cultured under different conditions, this community was shown to be a stable association, consisting of one obligate type II methanotroph and four or five heterotrophs possessing different nutritional and physiological characteristics. The results of experiments examining growth kinetics and nutritional relationships suggested that a number of complex interactions existed in the community in which the methanotroph was the only member able to grow on methane and to cometabolically initiate LAS transformation. These growth and metabolic activities of the methanotroph ensured the supply of a carbon source and specific nutrients which sustained the growth of four or five heterotrophs. In addition to the obligatory nutritional relationships between the methanotroph and heterotrophs, other possible interactions resulted in the modification of basic growth parameters of individual populations and a concerted metabolic attack on the complex LAS molecule. Most of these relationships conferred beneficial effects on the interacting populations, making the community adaptable to various environmental conditions and more efficient in LAS transformation than any of the individual populations alone.
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Singh, V., e A. K. Mittal. "Characterization of biofilm of a rotating biological contactor treating synthetic wastewater". Water Science and Technology 66, n.º 2 (1 de julho de 2012): 429–37. http://dx.doi.org/10.2166/wst.2012.221.
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A four-stage rotating biological contactor (RBC) was designed and operated to treat synthetic wastewater containing 1,000 mg/l chemical oxygen demand (COD) and 112 mg/l NH4+-N. A mixed culture bacterial biofilm was developed consisting of a heterotrophic bacterium Paracoccus pantotrophus, nitrifiers and other heterotrophs. Applying the peculiar characteristics of P. pantotrophus of simultaneous heterotrophic nitrification and aerobic denitrification, high simultaneous removal of carbon and nitrogen could be achieved in the fully aerobic RBC. The microbial community structure of the RBC biofilm was categorized based on the nitrate reduction, biochemical reactions, gram staining and morphology. The presence of P. pantotrophus within the RBC biofilm was confirmed with an array of biochemical tests. Isolates from the four stages of RBC were grouped into complete denitrifiers, incomplete denitrifiers and non-denitrifiers. This categorization showed a higher relative abundance of P. pantotrophus in the first stage as compared with subsequent stages, in which other nitrifiers and heterotrophs were significantly present. High total nitrogen removal of upto 68% was in conformity with observations made using microbial categorization and biochemical tests. The high relative abundance of P. pantotrophus in the biofilm revealed that it could successfully compete with other heterotrophs and autotrophic nitrifiers in mixed bacterial biomass.
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Tsuneda, S., S. Park, H. Hayashi, J. Jung e A. Hirata. "Enhancement of nitrifying biofilm formation using selected EPS produced by heterotrophic bacteria". Water Science and Technology 43, n.º 6 (1 de março de 2001): 197–204. http://dx.doi.org/10.2166/wst.2001.0374.
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The possibility of enhancing nitrifying biofilm formation rate with the aid of selected EPS produced by heterotrophic bacteria was investigated. When EPS production characteristics were examined for four kinds of heterotrophs isolated from a domestic wastewater treatment reactor, two strains obtained from biofilms (B1, B2) exhibited a higher polysaccharide production rate than those from suspended flocs (A1, A2). Among EPS components, the concentration of uronic acids gave a good correlation with flocculation ability, which suggests that acidic polysaccharides play a major role in bioaggregate formation. Addition of 1g/L D-glucuronic acid as an EPS substitute enhanced the homocoagulation rate of autotrophic Nitrosomonas europaea and altered its zeta potential from ñ30.4mV to +4.3mV, which indicates a possibility that particular EPS components produced by heterotrophs are utilized as neutralising reagents for nitrifying biofilm formation. Moreover, when heterotrophic isolates with Nitrobacter winogradskyi were cultured in batch with fabric supports, biofilm formed on the substratum. These experimental results suggest the application of selected EPS for enhancing nitrifying biofilm formation.
Teses / dissertações sobre o assunto "Culture heterotrophe"
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Camarena, Cristobal. "Lutein production and extraction improvements from a heterotrophic culture of scenedesmus almeriensis". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPAST085.
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Les microalgues sont considérées comme une solution biotechnologique aux problèmesmajeurs de ce siècle, offrant des réponses et des alternatives dans des domainestels que la malnutrition, les pénuries alimentaires, le changement climatique etla pollution. En tant qu'organismes photosynthétiques, les microalgues synthétisent denombreux composés afin d'exploiter la lumière du soleil pour leurs fonctions métaboliques, notamment la lutéine, un caroténoïde jaune essentiel pour l'alimentation humaine.Bien que la lutéine soit un composé associé à l'activité photosynthétique des microalgues,certaines espèces conservent la capacité de synthétiser cet important pigmentmême dans des conditions de culture hétérotrophe, ce qui permet d'augmenter la productivité de la biomasse et de la lutéine. Scenedesmus almeriensis a été rapportée comme une bonne productrice de lutéine dans des conditions phototrophiques, mais son faible taux de croissance par rapport à d'autres espèces de microalgues a entravé son potentiel.Cette thèse présente les résultats de la productivité en lutéine obtenue à partir d'uneculture hétérotrophe de Scenedesmus almeriensis, à la fois à l'échelle du laboratoire et àl'échelle pré-pilote. En plus d'atteindre des valeurs élevées de productivité en lutéine, sataille cellulaire plus grande et sa fragilité simplifient la récolte de la biomasse et l'extraction des pigments. Une méthode simplifiée d'extraction de la lutéine adaptée à cette espèce est également présentée. Ce procédé utilise l'éthanol comme solvant d'extraction et nécessite moins de temps et d'énergie, ce qui représente des avantages pour l'environnement et l'acceptation dans l'industrieMicroalgae are positioned as a biotechnological solution to major problems ofthis century, offering answers and alternatives in areas like malnutrition, foodshortages, climate change, and pollution. As photosynthetic organisms, microalgaesynthesize numerous compounds to harness sunlight for their metabolic functions,including lutein, a yellow carotenoid crucial for the human diet.Although lutein is a compound associated with the photosynthetic activity of microalgae,some species maintain the capacity to synthesize this important pigment even underheterotrophic conditions, allowing increased productivity of both biomass and lutein incultures supplemented with an organic carbon source. Scenedesmus almeriensis has been reported as a good lutein producer under phototrophic conditions, but its low growth rate compared to other microalgae species has hindered its potential.This thesis presents results of the lutein productivity obteained from a heterotrophicculture of Scenedesmus almeriensis, both at laboratory and pre-pilot scale. In addition toachieving high lutein productivity values, its larger cell size and fragility simplify biomassharvesting and pigment extraction. A simplified method for lutein extraction adaptedto this species is also presented. This process uses ethanol as an extraction solvent andrequires less time and energy, which represents environmental and product acceptanceadvantages
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Ip, Po-fung. "Elicitation of astaxanthin biosynthesis in dark-heterotrophic cultures of Chlorella zofingiensis". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B34617048.
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Sanz, Sáez Isabel. "Contribution of marine heterotrophic cultured bacteria to microbial diversity and mercury detoxification". Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671617.
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Els oceans conten aproximadament un total de 10^29 cèl·lules microbianes. Els bacteris marins són responsables de la major part de la respiració que es produeix en l’oceà i són essencials en els cicles biogeoquímics de la Terra. Estudiar la diversitat bacteriana dels ecosistemes marins i tenir accés als genomes mitjançant estudis dependents o independents de cultiu és important per desxifrar el potencial metabòlic dels bacteris marins.
El cultius ens aporten informació sobre la fisiologia bacteriana, ecologia i contingut genòmic, però la majoria dels esforços en aïllar bacteris marins provenen de la zona fòtica de l’oceà, deixant les profunditats marines menys explorades. En aquesta tesi, tècniques estàndard de cultiu han permès crear una col·lecció marina de cultius de bacteris heterotròfics (MARINHET), composada per més de 2000 aïllats, recuperats de diverses regions oceanogràfiques, de diverses profunditats (superfície, mesopelàgic i batipelàgic) i cobrint diverses estacions i anys. El Capítol 1 descriu la seva taxonomia, diversitat filogenètica i biogeografia i revela que un 37% de les soques aïllades són 100% idèntiques en el gen ribosomal 16S (16S rRNA) entre la zona fòtica (superfície) i afòtica (mesopelàgic i batipelàgic). A més, hem identificat Alteromonas i Erythrobacter entre els gèneres marins heterotròfics més comuns que recuperem en cultiu usant un medi marí estàndard.
Les tècniques tradicionals de cultiu generalment només recuperen una fracció petita de les comunitats bacterianes naturals, fenomen conegut com ‘la gran anomalia de recompte en placa’ i moltes de les soques que s’aïllen pertanyen a la biosfera rara. Tanmateix, no coneixem si aquests patrons, normalment descrits per als bacteris de la zona fòtica, també s’apliquen als bacteris de les profunditats. En el Capítol 2 he combinat els resultats obtinguts mitjançant tècniques dependents i independents de cultiu comparant les seqüències del 16S rRNA de la col·lecció MARINHET contra fragments de seqüenciació massiva del 16S rRNA, tant d’amplicons com de metagenomes, obtinguts de mostres globalment distribuïdes i de diferents profunditats. Trobem que una major proporció dels bacteris de l’oceà profund són cultivables i una fracció important dels aïllats té preferència a un estil de vida adherit a partícules. A més, confirmem que el dogma ‘menys de l’1% dels bacteris són cultivables’ ha de ser revisat ja que trobem variabilitat en les mostres de l’oceà profund, on fins a un 3% de les cèl·lules han sigut cultivades.
Els aïllats bacterians són un excel·lent material per a aplicacions biotecnològiques com la bioremediació de zones marines contaminades. El mercuri és un metall pesat tòxic i la seva forma més perillosa, el metilmercuri (MeHg), es bioacumula a la cadena tròfica marina. No obstant això, es coneix molt poc la tolerància de bacteris marins enfront del mercuri o la fisiologia d’aquelles soques que codifiquen l’operó dels gens de resistència (operó mer). El Capítol 3 descriu els resultats del mapeig funcional dels gens merA i merB, clau en la detoxificació, en una fracció de la col·lecció MARINHET. Ens centrem en dos generes marins, amb un potencial genètic per a la degradació del mercuri conegut, com són Alteromonas i Marinobacter. Revelem que els gens merAB estan àmpliament distribuïts en diferents regions oceanogràfiques i en diverses profunditats. Addicionalment, hem seleccionat una soca d’ Alteromonas mediterranea per a futurs estudis de bioremediació degut a la seva alta tolerància i capacitat de degradació de diferents formes de mercuri.Los océanos contienen aproximadamente un total de 10^29 células microbianas. Las bacterias marinas son responsables de la mayor parte de la respiración que se produce en el océano y son esenciales en los ciclos biogeoquímicos de la Tierra. Estudiar la diversidad bacteriana de los ecosistemas marinos y tener acceso a los genomas mediante estudios dependientes e independientes de cultivo es importante para descifrar el potencial metabólico de las bacterias marinas. Los cultivos nos aportan información sobre la fisiología bacteriana, ecología y contenido genómico, pero la mayoría de los esfuerzos en aislar bacteria marinas provienen de la zona fótica del océano, dejando las profundidades marinas menos exploradas. En esta tesis, técnicas estándar de cultivo han permitido crear una colección marina de bacterias heterótrofas (MARINHET), compuesta por más de 2000 aislados, recuperados de varias regiones oceanográficas, de varias profundidades (superficie, mesopelágico y batipelágico), y cubriendo varias estaciones y años. El Capítulo 1 describe su taxonomía, diversidad filogenética y biogeografía y revela que un 37% de las cepas son 100% idénticas en la secuencia parcial del gen ribosomal 16S (16S rRNA) entre la zona fótica (superficie) y afótica (mesopelágico y batipelágico). Además, hemos identificado Alteromonas y Erythrobacter entre los géneros marinos heterótrofos más comunes que recuperamos en cultivo usando un medio marino estándar. Las técnicas tradicionales de cultivo generalmente solo recuperan una fracción pequeña de las comunidades bacterianas naturales, fenómeno conocido como ‘la gran anomalía de recuento en placa’ y muchas de las cepas que se aíslan pertenecen a la biosfera rara. Sin embargo, no conocemos si estos patrones, normalmente descritos para las bacterias de superficie, también se aplican en las profundidades. En el Capítulo 2 he combinado resultados obtenidos mediante técnicas dependientes e independientes de cultivo comparando las secuencias del 16S rRNA de la colección MARINHET contra los fragmentos de secuenciación masiva del 16S rRNA (de amplicones y metagenomas), obtenidos de muestras globalmente distribuidas y de diferentes profundidades. Una mayor proporción de las bacterias del océano profundo son cultivables y una fracción importante de los aislados tiene preferencia a un estilo de vida adherido a partículas. Además, confirmamos que el dogma ‘menos del 1% de las bacterias son cultivables’ deber ser revisado ya que encontramos variabilidad en las muestras de profundidad, donde hasta un 3% de las células se han podido aislar. Los aislados bacterianos son un excelente material para aplicaciones biotecnológicas, como la biorremediación de zonas marinas contaminadas. El mercurio es un metal pesado tóxico y su forma más peligrosa, el metilmercurio (MeHg), se bioacumula en la cadena trófica marina. No obstante, se conoce muy poco la tolerancia de bacterias marinas frente al mercurio o la fisiológia de aquellas cepas que codifican los genes de resistencia (operón mer). El Capítulo 3 describe los resultados del mapeo funcional de los genes merA y merB, clave en la detoxificación, en una fracción de la colección MARINHET. Nos centramos en dos géneros marinos, con un potencial genético para la degradación del mercurio previamente descrito en la literatura, como son Alteromonas y Marinobacter. Desvelamos que los genes merAB están ampliamente distribuidos en diferentes regiones oceanográficas y en varias profundidades. Adicionalmente, hemos seleccionado una cepa de Alteromonas mediterranea para futuros estudios de biorremediación debido a su alta tolerancia y capacidad de degradación de diferentes formas de mercurio.
The world’s oceans sustain the life for an estimated total of 10^29 microbial cells. Marine bacteria are responsible for most part of the ocean respiration and are key in most biogeochemical cycles of the Earth. Accordingly, the study of the bacterial diversity present in different marine ecosystems is essential, and having access to their genomes through isolation or genomic centric studies is important to decipher their metabolic potential. Isolation of marine microorganisms is fundamental to gather information about their physiology, ecology and genomic content. To date, most of the bacterial isolation efforts have focused on the photic ocean leaving the deep ocean less explored. In this thesis, standard plating techniques allowed to create a marine culture collection of heterotrophic bacteria (MARINHET). More than 2000 isolates were retrieved from samples collected from a variety of oceanographic regions, from different depths including surface, mesopelagic and bathypelagic waters, and also covering different seasons and years. Chapter 1 describes the taxonomy, the phylogenetic diversity and the biogeography of culturable heterotrophic marine bacteria, and reveals that an important percentage of the strains (37%) are 100% identical in their partial 16S rRNA gene between photic and aphotic layers. In addition, we identified Alteromonas and Erythrobacter genera as the most frequently retrieved heterotrophic bacteria from the ocean in standard marine agar medium. It is a long-standing observation that traditional culture techniques only retrieve a small fraction of the microbial diversity found in natural environments including marine ecosystems, what is known as ‘the great plate count anomaly’. In addition, most of the retrieved isolates belong to the so-called rare biosphere. However, we do not know if these patterns, usually described for bacteria living in the photic ocean, also apply for the deep ocean bacteria. In Chapter 2 of this thesis, I combined results from culture-dependent and -independent techniques by comparing the 16S rRNA partial sequences of the MARINHET isolates with 16S rRNA amplicon Illumina TAGs (16S iTAGs) and metagenomic TAGs (miTAGs) from surface, mesopelagic and bathypelagic samples globally distributed. A high proportion of bacteria inhabiting the deep ocean could be retrieved by pure culture techniques and a significant fraction of the isolates preferred a lifestyle attached to particles. Additionally, I revised the axiom that ‘less than 1% of bacteria can be cultured’, finding variability between mesopelagic and bathypelagic samples, where up to 3% of the cells could be cultured. Bacterial isolates also represent a valuable genetic reservoir for biotechnology applications, such as bioremediation strategies of marine polluted environments. Mercury is one of the most toxic heavy metals in the planet and its most dangerous form, methylmercury (MeHg), is being bioaccumulated in the marine food web. However, little is known about the tolerance capacity and phenotypic characterization of marine bacteria codifying the mercury resistance operon (mer operon). Chapter 3 describes the functional screening of merA and merB genes, which are key in the mercury detoxification process, in well know marine genera with described genetic potential for mercury detoxification, such as Alteromonas and Marinobacter. I reported that the merAB genes from these two genera are widely distributed in different oceanographic regions and depths. In addition, I selected a promising candidate, phylogenetically affiliated to Alteromonas mediterranea, for future bioremediation studies due to its high tolerance and degradation ability of different mercury forms.
Universitat Autònoma de Barcelona. Programa de Doctorat en Microbiologia
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Strate, Jessica Lorene. "Characterization and activity comparisons of methanotrophic-heterotrophic mixed cultures derived from a landfill environment". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0009061.
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溫志友 e Zhiyou Wen. "A high yield and productivity strategy for eicosapentaenoic acid production by the diatom Nitzschia laevis in heterotrophic culture". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242418.
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Wen, Zhiyou. "A high yield and productivity strategy for eicosapentaenoic acid production by the diatom Nitzschia laevis in heterotrophic culture". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23242097.
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Ducos, Jean-Paul. "Croissance et metabolisme primaire de suspensions heterotrophes de catharanthus roseus en fermenteur : importance de la phase gazeuse". Toulouse, INSA, 1986. http://www.theses.fr/1986ISAT0031.
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Berthold, Erwin David. "Enhancing Algal Biomass and Lipid Production through Bacterial and Fungal Co-Culture". FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2563.
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This thesis investigates the effects of co-culturing microorganisms including 37 yeast, 38 bacteria, nine diazotrophic cyanobacteria, and three fungi on biomass and lipid production in fresh- and saltwater algae. Algal lipid content was measured using Nile Red method and gravimetric techniques. Among the algal strains tested, freshwater Coelastrum sp. 46-4, and saltwater Cricosphaera sp. 146-2-9, showed enhanced biomass yield and lipid content in response to co-culture with bacteria, cyanobacteria, and fungi. While co-culture with yeast caused inhibition of algal productivity, no difference in algal productivity was observed between nitrogen-free diazotrophic cyanobacterial co-culture and nitrogen-replete monoalgal culture. Results indicated that extracellular compounds from the freshwater bacteria Pseudomonas stutzeri and marine fungus Fusarium sp. significantly account for stimulation of lipid accumulation within algal cells, while co-cultivation with live microorganism cells stimulated biomass production in algae.
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Fuller, Andrew Kenneth Radburne. "The grazing and growth rates of some marine protozoa measured in batch and continuous culture with particular reference to the heterotrophic dinoflagellate Oxyrrhis marina". Thesis, Royal Holloway, University of London, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325771.
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Zhang, Jing. "Development of Chlorella vulgaris and Saccharomyces cerevisiae in immobilized cultures". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASC034.
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Chlorella vulgaris (C. vulgaris) est un organisme modèle qui présente un potentiel commercial élevé dans le domaine de l'alimentation et de l'énergie, avec une faisabilité prouvée de cultures sous forme de biofilms et de co-culture de levures/microalgues pour la valorisation in situ du CO2 dans les processus biotechnologiques. Ce travail de doctorat se concentre sur les colonies immobilisées dans des cultures pures ou mixtes. Il vise une meilleure compréhension des interactions au sein des colonies et entre colonies, avec pour objectif ultime de comprendre et d'optimiser les co-cultures.Pour atteindre ces objectifs, un protocole complet et des dispositifs expérimentaux innovants ont été développés, notamment des techniques d'inoculation, des dispositifs de culture immobilisée avec capteurs de gaz, l'imagerie 3-D à l'aide d'un microscope à lumière structurée, le traitement d'images, un bilan gazeux calibré et l'analyse des données. Des précautions ont également été prises concernant les conditions d'incubation, la détermination de la masse sèche, la concentration en glucose, la taille et la densité des cellules.Tout d'abord, le développement de colonies uniques de C. vulgaris a été étudié dans des conditions hétérotrophes. Sur la base du modèle biologique proposé pour la dynamique de croissance en hauteur et en rayon, nous avons conclu que les colonies se développaient à un taux constant dans la direction horizontale et à un taux décroissant dans la direction verticale. Ces tendances sont cohérentes avec les effets cumulés de la disponibilité du glucose et de l'oxygène. Une calotte sphérique décrit le mieux la forme des colonies pendant la période de croissance. L'interaction intraspécifique de C. vulgaris a été étudiée en faisant croître plusieurs colonies sur la même plaque à des distances de initiales différentes : 1,5 mm, 3 mm et 15 mm. Aucun effet significatif de la coalescence des colonies n'a été observé sur les taux de croissance en rayon et en hauteur.Ensuite, l'effet de la lumière a été testé de deux manières : présence de lumière durant toute la culture et exposition à la lumière après une première période hétérotrophe. La forme de la colonie est significativement affectée par le mode de culture : la colonie en croissance hétérotrophe garde une calotte sphérique, tandis que la colonie en croissance mixotrophe atteint une forme cylindrique, en raison d'une croissance radiale presque complètement arrêtée après quelques jours. Grâce au dispositif de mesure des gaz, les données brutes ont été analysées à l'aide d'une équation de bilan gazeux pour obtenir les termes source biologique d'O2 et de CO2. Le rapport de masse du gaz sur la masse sèche de la cellule a été déterminé pour les différentes conditions de croissance. Une synergie est mise en évidence entre la photosynthèse au sommet de la colonie et l’hétérotrophie à la base.L'interaction inter-espèces de C. vulgaris et S. cerevisiae a été étudiée à deux niveaux : au niveau des cellules dans la même colonie et entre colonies. Au niveau de la colonie, des colonies de C. vulgaris et de S. cerevisiae ont été inoculées avec deux distances de séparation initiales différentes (3 mm et 15 mm). Les colonies ont été observées en continu pendant un mois. Même si des recherches supplémentaires sont nécessaires, la croissance et l'interaction observées semblent s'expliquer principalement par le taux de croissance beaucoup plus élevé de la levure. Après avoir fusionné, les colonies de S. cerevisiae finissent par envelopper les colonies de C. vulgaris. Au niveau des cellules, les colonies mélangées de C. vulgaris et de S. cerevisiae ont été observées en 3D. En raison de leur croissance rapide, les cellules de S. cerevisiae finissent par dominer l'ensemble de la colonie, à l'exception de quelques cellules de C. vulgaris présentes au cœur de la colonie et sur le dessus. Les cellules de C. vulgaris cessent presque de croître lorsque les nutriments sont limitésChlorella vulgaris (C. vulgaris) is a model organism that has high commercial potential in the food and energy field, with proved feasibility of cultures as biofilms and yeast/ microalgae co-culture for in situ CO2 mitigation in biotechnological processes. This PhD work focuses on immobilized colonies in pure or mixed cultures. It proposes a better understanding of the interactions within and between colonies, with the ultimate goal of understanding and optimizing co-cultures.To archive these goals, a comprehensive protocol and required innovative experimental devices were developed including inoculation techniques, immobilized culture devices with gas sensors, 3-D imaging using a structured-light microscope, image processing, calibrated gas balance equation and data analysis. Care was also taken regarding incubation conditions, determination of dry mass, glucose concentration, cell size and density.Firstly, the development of single C. vulgaris colonies under heterotrophic conditions was studied. Based on the biological model proposed for the growth dynamics in height and radius, we concluded that the colonies expanded at a constant rate in the horizontal direction and a decreasing rate in the vertical direction. The trends are consistent with the cumulative effects of glucose and oxygen availability. A spherical cap best describes the shape of the colonies during the growth period. The intraspecies interaction of C. vulgaris was investigated by growing several colonies on the same plate with different initial separation distances: 1.5 mm, 3mm, and 15 mm. No significant effects of colony merging were observed on the growth rates in radius and height.Then, the effect of light was tested in two ways: presence of light throughout the culture and exposition to light after a first, purely heterotrophic, period. The shape of colony is significantly affected by the cultivation mode: the heterotrophic growth colony keeps a spherical cap, while the mixotrophic growth colony reaches a cylindrical shape, due to a radial growth almost completely stopped after some days. Thanks to the gas measurement device, the raw data were analyzed using a gas balance equation to obtain the biological source terms of O2 and CO2. Gas yield (mass ratio of gas to dry mass of cell) are proposed for the different growth conditions. A synergy is highlighted between photosynthesis at the top of the colony and heterotrophy at the base.The interspecies interaction of C. vulgaris and S. cerevisiae were studied at two levels: cell-cell level within the same colony and colony-colony level. At the colony-colony level, colonies of C. vulgaris and S. cerevisiae were inoculated with two different initial separation distances (3 mm and 15 mm). Colonies were observed continuously for one month. Even though additional investigation is needed, the observed growth and interaction seems to be mostly explained by the much larger growth rate of yeast. After merging S. cerevisiae colonies eventually envelop C. vulgaris colonies. At the cell-cell level, C. vulgaris and S. cerevisiae intermixed colonies were observed in 3D. Due to its fast grow, S. cerevisiae cells eventually dominate the whole colony, at the exception of some C. vulgaris cells present in the core of the colony and on the top. C. vulgaris cells almost stop growing when the nutrients are limited
Livros sobre o assunto "Culture heterotrophe"
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Kirchman, David L. Microbial growth, biomass production, and controls. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0008.
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Soon after the discovery that bacteria are abundant in natural environments, the question arose as to whether or not they were active. Although the plate count method suggested that they were dormant if not dead, other methods indicated that a large fraction of bacteria and fungi are active, as discussed in this chapter. It goes on to discuss fundamental equations for exponential growth and logistic growth, and it describes phases of growth in batch cultures, continuous cultures, and chemostats. In contrast with measuring growth in laboratory cultures, it is difficult to measure in natural environments for complex communities with co-occurring mortality. Among many methods that have been suggested over the years, the most common one for bacteria is the leucine approach, while for fungi it is the acetate-in ergosterol method. These methods indicate that the growth rate of the bulk community is on the order of days for bacteria in their natural environment. It is faster in aquatic habitats than in soils, and bacteria grow faster than fungi in soils. But bulk rates for bacteria appear to be slower than those for phytoplankton. All of these rates for natural communities are much slower than rates measured for most microbes in the laboratory. Rates in subsurface environments hundreds of meters from light-driven primary production and high organic carbon conditions are even lower. Rates vary greatly among microbial taxa, according to data on 16S rRNA. Copiotrophic bacteria grow much faster than oligotrophic bacteria, but may have low growth rates when conditions turn unfavorable. Some of the factors limiting heterotrophic bacteria and fungi include temperature and inorganic nutrients, but the supply of organic compounds is perhaps most important in most environments.
Capítulos de livros sobre o assunto "Culture heterotrophe"
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Cortese, Enrico, Luca Carraretto, Barbara Baldan e Lorella Navazio. "Arabidopsis Photosynthetic and Heterotrophic Cell Suspension Cultures". In Methods in Molecular Biology, 167–85. New York, NY: Springer US, 2020. http://dx.doi.org/10.1007/978-1-0716-0880-7_8.
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Kovar, Karin, Pavel Přibyl e Markus Wyss. "Microalgae Grown under Heterotrophic and Mixotrophic Conditions". In Industrial Scale Suspension Culture of Living Cells, 164–85. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527683321.ch04.
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Imseng, Nicole, Stefan Schillberg, Cornelia Schürch, Daniel Schmid, Kai Schütte, Gilbert Gorr, Dieter Eibl e Regine Eibl. "Suspension Culture of Plant Cells Under Heterotrophic Conditions". In Industrial Scale Suspension Culture of Living Cells, 224–58. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527683321.ch07.
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Ogbonna, James Chukwuma, e Mark P. McHenry. "Culture Systems Incorporating Heterotrophic Metabolism for Biodiesel Oil Production by Microalgae". In Biofuel and Biorefinery Technologies, 63–74. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-16640-7_4.
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Singh, Amit K., e Daniel C. Ducat. "Generation of Stable, Light-Driven Co-cultures of Cyanobacteria with Heterotrophic Microbes". In Plant Synthetic Biology, 277–91. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-1791-5_16.
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Mannan, R. Mannar, e Himadri B. Pakrasi. "The Photosynthetic Apparatus in Autotrophic and Heterotrophic Cultures of Anabaena Variabilis ATCC 29413". In Research in Photosynthesis, 425–28. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-009-0383-8_95.
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Gu, Ji-Dong, e Yoko Katayama. "Microbiota and Biochemical Processes Involved in Biodeterioration of Cultural Heritage and Protection". In Microorganisms in the Deterioration and Preservation of Cultural Heritage, 37–58. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_2.
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AbstractThe world cultural heritage sites face new challenges for an effective protection and management because of destruction and damage initiated by both natural and anthropogenic causes. Fresh rock and sandstone surfaces of buildings are quickly colonized and covered by a layer of microorganisms, including phototrophs, lithotrophs, and heterotrophs to form a biofilm that alters the local conditions of the stone surfaces, especially under the favorable tropical climate conditions for autotrophic microorganisms and plants. Biofilms had been studied with indigenous or pure cultures of isolated microorganisms, but the selective ones that contribute to deterioration of the cultural heritage cannot be confirmed easily. Currently, high-throughput sequencing and metegenomics analyses are capable of obtaining microbial community and composition in great depth, but they also suffer from similar weakness unable to identify the culprits in the community. With these as background, this article presents a different approach by focusing on the biochemical processes and the responsible microorganisms involved to reveal the destruction processes for management and protection. Among these different functional groups of microorganisms, lichens are known as pioneering rock-decomposing microorganisms, and both sulfur-oxidizing bacteria and fungi participate in the decomposition of sandstone via sulfur cycling and initiation of salt attack of the stone afterward, resulting in defoliation and cracking of stone. Other microorganisms including ammonia-oxidizing bacteria and archaea, especially the latter, have been recently detected on sandstone monuments providing evidence on the new organisms involved in the deterioration of cultural heritage and buildings. In addition, fungi can colonize the surfaces of the matured biofilms and play a new role in the removal of them, which has a potential biotechnological application in conservation of cultural heritage. The new proposed approach by focusing the microorganisms with identified biochemical function is more productive than a description of the community composition and assembly when assessing cultural heritage biodeterioration, and this provides basic and useful information for effective protection strategies and management.
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Wen, Z. Y., e F. Chen. "Optimization of Nitrogen Sources for the Production of Eicosapentaenoic Acid by the Diatom Nitzschia Laevis in Heterotrophic Cultures". In Algae and their Biotechnological Potential, 55–68. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9835-4_3.
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Benlloch, Susana, Francisco Rodríguez-Valera, Silvia G. Acinas e Antonio J. Martínez-Murcia. "Heterotrophic bacteria, activity and bacterial diversity in two coastal lagoons as detected by culture and 16S rRNA genes PCR amplification and partial sequencing". In Coastal Lagoon Eutrophication and ANaerobic Processes (C.L.E.AN.), 3–17. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1744-6_1.
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Häuser, Christiane, Johannes Jung e Klaus Grossmann. "Changes in abscisic acid levels of heterotrophic cell suspension cultures caused by the plant growth retardant BAS 111… W and possible physiological consequences". In Progress in Plant Growth Regulation, 173–79. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2458-4_18.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Culture heterotrophe"
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Savanina, Y. V. "INTENSIFICATION OF BIOLOGICAL SELF-CLEANING UNDER CONDITIONS OF SLOPE DISCHARGE." In NOVEL TECHNOLOGIES IN MEDICINE, BIOLOGY, PHARMACOLOGY AND ECOLOGY, 225–29. LLC Institute Information Technologies, 2024. http://dx.doi.org/10.47501/978-5-6044060-4-5.225-229.
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The article studies the possibilities of creating biohybrid materials based on a mixed-separate culture of cyanobacteria and heterotrophic bacteria isolated from polluted environments, and their use in conditions of excess pollution.
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MARONEZE, M. M., G. J. G. TEIXEIRA, C. NEVES, L. Q. ZEPKA, M. I. QUEIROZ e E. JACOB-LOPES. "EVALUATION OF SUBSTRATE LIMITATION KINETICS IN HETEROTROPHIC MICROALGAL CULTURES". In XI Congresso Brasileiro de Engenharia Química em Iniciação Científica. São Paulo: Editora Edgard Blücher, 2015. http://dx.doi.org/10.5151/chemeng-cobeqic2015-314-33907-260288.
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Stramski, Dariusz, Marian Sedlak, David Tsai, Eric J. Amis e Dale A. Kiefer. "Dynamic light scattering by cultures of heterotrophic marine bacteria". In San Diego '92, editado por Gary D. Gilbert. SPIE, 1992. http://dx.doi.org/10.1117/12.140688.
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Maroneze, Mariana Manzoni, Cristina Neves, Leila Queiroz Zepka, Maria Isabel Queiroz e Eduardo Jacob Lopes. "EVALUATION OF SUBSTRATE LIMITATION KINETICS IN HETEROTROPHIC MICROALGAL CULTURES". In Simpósio Nacional de Bioprocessos e Simpósio de Hidrólise Enzimática de Biomassa. Campinas - SP, Brazil: Galoá, 2015. http://dx.doi.org/10.17648/sinaferm-2015-33510.
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Elvert, Marcus, Qingzeng Zhu, Jonathan Gropp, Heidi Taubner, Itay Halevy, Kai-Uwe Hinrichs e Gunter Wegener. "Clues on methane’s biogeochemistry and associated heterotrophic microbes in marine sediments from AOM enrichment cultures". In Goldschmidt2023. France: European Association of Geochemistry, 2023. http://dx.doi.org/10.7185/gold2023.16918.
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Wei, X., W. Yang e S. Choi. "A HIGH POWER-DENSITY, SELF-SUSTAINED HYBRID BIO-SOLAR CELL WITH CO-CULTURE OF HETEROTROPHIC AND PHOTOSYNTHETIC BACTERIA". In 2016 Solid-State, Actuators, and Microsystems Workshop. San Diego: Transducer Research Foundation, 2016. http://dx.doi.org/10.31438/trf.hh2016.106.
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Iungin, Olga, Ievgeniia Prekrasna, Ihor Bortyanuy, Valeriia Maslak e Saulius Mickevičius. "Plant Growth-Promoting Characteristics of Antarctic Endophytic Bacteria". In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.ii.11.
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The work is focused on studying bacteria associated with vascular plants in Antarctic region. Climate changes affecting the Antarctic Peninsula favor the successful colonization of ice-free lands by two Antarctic vascular plants (Deschampsia antarctica and Colobanthus quitensis). Bacteria isolated from D. antarctica collected during the 25th Ukrainian Antarctic Expedition (January-April 2020) along the Western part of the Antarctic Peninsula were studied for plant growth-promoting characteristics (nitrogen fixation, phosphate solubilization, cyclic lipopeptide production, exoprotease production, motility and carbohydrate utilization). The heterotrophy of bacterial isolated from D. antarctica and the presence of a wide range of saccharolytic enzymes for the utilization of mono- and disaccharides in studied cultures were shown. This may indicate the plasticity of metabolism and the high adaptation potential of microorganisms associated with D. antarctica. PGPT of studied bacteria were mostly presented by nitrogen-fixing ability and cyclic lipopeptides synthesis.
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Molokwane, Pulane E., e Evans M. N. Chirwa. "Development of a Carbon-14 Bioseperation Technique for Cleanup of Nuclear Graphite". In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7164.
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A preliminary study on the bioseperation of Carbon-14 was carried out using a mixed-culture of microorganisms obtained from the Pebble Bed Modular Reactor Company (PBMR). The culture demonstrated the ability to bioaccumulate radiocarbon-14 (C-14) from solution. The experiment consisting of a growth vessel and a biofilter connected in a closed loop. The biofilter was not installed for the purpose of treatment but rather as a method of isolation of microorganisms for further processing. Significant amounts of C-14 were detected in the trapped cells in the biofilter, significantly higher than in controls taken before adding carbon sources containing C-14. The microorganisms were grown under micro-aerobic conditions with graphite carbon and commercially purchased powdered carbon as the predominant supplied carbon sources. Small amounts of sucrose (500 mg/L) were added at 48 hour intervals to promote the growth of heterotrophic microorganisms. Additional work is required to determine the amount of C-14 escaping through gases produced as a product of metabolism (CO2 and CO) and the total carbon metabolized by the microorganisms in order to report with accuracy the degree of separation of C-14 from the C-14/C-12 mixture. A proof of concept study is underway to determine the C-14 mass balance, characterize the microorganisms in the reactor, and establish the presence or absence of processes that might have affected the preliminary observations.
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Jurminskaia, Olga, Igor Shubernetskii e Nadejda Andreev. "Effect of lactobacilli on autochthonous microflora of fish ponds". In 5th International Scientific Conference on Microbial Biotechnology. Institute of Microbiology and Biotechnology, 2022. http://dx.doi.org/10.52757/imb22.47.
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The abundance of bacterioplankton and bacteriobenthos in fish ponds is largely determined by three main factors: water temperature, fish stocking density and fertilizers used. As the water temperature rises, the intensity of the metabolic processes of the microbiota increases, and their number increases significantly. The greatest number of microorganisms is contained in the surface layer of bottom sediments. Intensive consumption of the oxygen by bacterioplankton and bacteriobenthos can lead to fish kills. The use of probiotics in aquaculture is of great interest: their influence on the immunostimulation of farmed fish, direct inhibition of pathogenic bacteria and improvement of pond water quality have been studied by many researchers. In order to determine measures to improve water quality in fish ponds, the laboratory experiment with the probiotic Lactobacillus acidophilus was carried out in the conditions of the Laboratory of Hydrobiology and Ecotoxicology. In this experiment, water samples were collected from the fish ponds of the "Ghidrin-Falesti Fish Enterprise" in RM. The degree of water body organic pollution is characterised by the hydrochemical parameter BOD5, which varied from 8 to 28 (mg/L O2) in water samples of these fish ponds. In accordance with the "Regulations" in force in the Republic of Moldova (2013), BOD5 values > 7 (mg/L O2) correspond to water quality class V. Thus, in terms of the amount of organic substrate, the water in these ponds is a good habitat for heterotrophic microorganisms. As a result of the development of the scientific basis of the theory of fertilisation of fishponds by Soviet hydrobiologists (N. Arnold, G. Vinberg, V. Zhadin, A. Rodina, etc.) the following was revealed: when fish is raised in high stocking with artificial compound feed, the task arises to limit bacterial development, i.e. to manage bacterial processes in the fish ponds. The task remains relevant today. The aim of the experiment was to test the ability of lactobacilli to survive in the bottom layer of a fish pond in comparison with autochthonous microflora. For this purpose, water samples from the Calugar, Girla and Fagadau ponds were divided into two aliquots: matrix (natural sample) and matrix + lactobacilli. Lactobacilli are non-pathogenic Gram-positive microorganisms with high enzymatic activity. In relation to oxygen, they are microaerophiles. By type of nutrition, they are chemoheterotrophs, using organic compounds as a source of energy and carbon. All aliquots were incubated at 22°C without aeration and also without access to light to minimise the photosynthetic activity of phytoplankton. After five days, each aliquot was inoculated (at the appropriate dilution) into Petri dishes on Tergitol 7 agar (without TTC) and incubated at 22°C. In sanitary microbiology, MRS agar is used for testing lactobacilli and cultivation is carried out at (30 - 35) °C. In our experiment, the aim was not to create the specific conditions for lactobacilli. We used Tergitol 7 agar, which contains lactose as opposed to MRS agar, which contains dextrose. To find out the ability to grow on Tergitol 7 agar and to determine the specific characteristics of the colonies, a Lactobacillus acidophilus culture was inoculated on this medium and cultivated under the same conditions as the test samples. The results of the experiment are presented below: Fagadau Girla Calugar Matrix on the day of sampling, 103 CFU/mL 3,3 3,2 2,5 Matrix after 5 days, 103 CFU/mL 30 10 5 Matrix + L. acidophilus after 5 days, 103 CFU/mL 4725 1805 2625 Thus, under oxygen-deficient conditions, the autochthonous microflora of fish ponds cannot withstand competition with lactobacilli, which are microaerophiles. If the results of the laboratory experiment are confirmed in real conditions, lactobacilli may be recommended for the suppression of autochthonous microflora, which are intensive oxygen consumers in summer biocenoses.
Relatórios de organizações sobre o assunto "Culture heterotrophe"
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Phelps, T. J., D. Ringelberg, A. T. Mikell, D. C. White e C. B. Fliermans. Mineralization of trichloroethylene by heterotrophic enrichment cultures. Office of Scientific and Technical Information (OSTI), dezembro de 1988. http://dx.doi.org/10.2172/666263.
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Shpigel, Muki, Allen Place, William Koven, Oded (Odi) Zmora, Sheenan Harpaz e Mordechai Harel. Development of Sodium Alginate Encapsulation of Diatom Concentrates as a Nutrient Delivery System to Enhance Growth and Survival of Post-Larvae Abalone. United States Department of Agriculture, setembro de 2001. http://dx.doi.org/10.32747/2001.7586480.bard.
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The major bottlenecks in rearing the highly priced gastropod abalone (Haliotis spp.) are the slow growth rate and the high mortality during the first 8 to 12 weeks following metamorphosis and settling. The most likely reason flor these problems is related to nutritional deficiencies in the diatom diet on which the post larvae (PL) feed almost exclusively in captivity. Higher survival and improved growth rate will reduce the considerable expense of hatchery-nursery resisdence time and thereflore the production costs. BARD supported our research for one year only and the support was given to us in order to prove that "(1) Abalone PL feed on encapsulated diatoms, and (2) heterotrophic diatoms can be mass produced." In the course of this year we have developed a novel nutrient delivery system specifically designed to enhance growth and survival of post-larval abalone. This approach is based on the sodium-alginate encapsulation of heterotrophically grown diatoms or diatom extracts, including appetite-stimulating factors. Diatom species that attract the PL and promote the highest growth and survival have been identified. These were also tested by incorporating them (either intact cells or as cell extracts) into a sodium-alginate matrix while comparing the growth to that achieved when using diatoms (singel sp. or as a mixture). A number of potential chemoattractants to act as appetite-stimulating factors for abalone PL have been tested. Preliminary results show that the incorporation of the amino acid methionine at a level of 10-3M to the sodim alginate matrix leads to a marked enhancement of growth. The results ol these studies provided basic knowledge on the growth of abalone and showed that it is possible to obtain, on a regular basis, survival rates exceeding 10% for this stage. Prior to this study the survival rates ranged between 2-4%, less than half of the values achieved today. Several diatom species originated from the National Center for Mariculture (Nitzchia laevis, Navicula lenzi, Amphora T3, and Navicula tennerima) and Cylindrotheca fusiformis (2083, 2084, 2085, 2086 and 2087 UTEX strains, Austin TX) were tested for heterotrophic growth. Axenic colonies were initially obtained and following intensive selection cycles and mutagenesis treatments, Amphora T3, Navicula tennerima and Cylindrotheca fusiformis (2083 UTEX strain) were capable of growing under heterotrophic conditions and to sustain highly enriched mediums. A highly efficient selection procedure as well as cost effective matrix of media components were developed and optimized. Glucose was identified as the best carbon source for all diatom strains. Doubling times ranging from 20-40 h were observed, and stable heterotroph cultures at a densities range of 103-104 were achieved. Although current growth rates are not yet sufficient for full economical fermentation, we estimate that further selections and mutagenesis treatments cycles should result in much faster growing colonies suitable for a fermentor scale-up. As rightfully pointed out by one of the reviewers, "There would be no point in assessing the optimum levels of dietary inclusions into micro-capsules, if the post-larvae cannot be induced to consume those capsules in the first place." We believe that the results of the first year of research provide a foundationfor the continuation of this research following the objectives put forth in the original proposal. Future work should concentrate on the optimization of incorporation of intact cells and cell extracts of the developed heterotrophic strains in the alginate matrix, as well as improving this delivery system by including liposomes and chemoattractants to ensure food consumption and enhanced growth.
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Koven, William, Gordon Grau, Benny Ron e Tetsuya Hirano. Improving fry quality, survival and growth in commercially farmed fish by dietary stimulation of thyroid hormone production in premetamorphosing larvae. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7695856.bard.
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There is a direct correlation between successful metamorphosis from larvae to post-larvae and the quality of the resultant juveniles or fry. Juvenile quality, in turn, is a major factor influencing fish production level and market price. However, following the profound morphological and physiological changes occurring during metamorphosis, the emerging juveniles in some species characteristically demonstrate heterotrophic growth, poor pigmentation, cannibalism and generally poor survival. The white grouper (Epinephelus aeneus) in Israel and the Pacific threadfin (Polydactylussexfilis) in Hawaii are two promising candidates for mariculture that have high market value but a natural fishery that has sharply declined in recent years. Unfortunately, their potential for culture is severely hampered by variable metamorphic success limiting their production. The main objective was to compare the efficacy and economic viability of dietary or environmental iodine on metamorphic success and juvenile quality in the white grouper and the pink snapper which would lead to improved commercial rearing protocols and increased production of these species both in Israel and the US. The Hawaii Institute of Marine Biology encountered problems with the availability of pink snapper brood stock and larvae and changed to Pacific threadfin or moi which is rapidly becoming a premier aquaculture species in Hawaii and throughout the Indo-Pacific. The white grouper brood stock at the National Center for Mariculture was lost as a result of a viral outbreak following the sudden breakdown of the ozone purification system. In addition, the NCM suffered a devastating fire in the fall of 2007 that completely destroyed the hatchery and laboratory facilities although the BARD project samples were saved. Nevertheless, by studying alternate species a number of valuable findings and conclusions that can contribute to improved metamorphosis in commercially valuable marine species resulted from this collaborative effort. The Israeli group found that exposing white grouper larvae to external TH levels synchronized and increased the rate of metamorphosis. This suggested that sub-optimal synthesis of TH may be a major factor causing size heterogeneity in the larval population and high mortality through cannibalism by their larger more metamorphosed cohorts. Two protocols were developed to enrich the larvae with higher levels of the TH precursor, iodine; feeding iodine enriched Artemia or increasing the level of seawater iodine the larvae are exposed to. Results of accumulated iodine in gilthead seabream larvae indicated that the absorption of iodine from the water is markedly more efficient than feeding iodine enriched Artemia nauplii. Samples for TH, which will be analyzed shortly, will be able to determine if another dietary factor is lacking to effectively utilize surplus tissue iodine for TH synthesis. Moreover, these samples will also clarify which approach to enriching larvae with iodine, through the live food or exposure to iodine enriched seawater is the most efficient and cost effective. The American group found that moi larvae reared in ocean water, which possessed substantially higher iodine levels than those found in seawater well water, grew significantly larger, and showed increased survival compared with well water reared larvae. Larvae reared in ocean water also progressed more rapidly through developmental stages than those in low-iodine well seawater. In collaboration with Israeli counterparts, a highly specific and precise radioimmunoassay procedure for thyroid hormones and cortisol was developed. Taken altogether, the combined Hawaiian and Israeli collaborative research suggests that for teleost species of commercial value, adequate levels of environmental iodine are more determinate in metamorphosis than iodine levels in the live zooplankton food provided to the larvae. Insuring sufficiently high enough iodine in the ambient seawater offers a much more economical solution to improved metamorphosis than enriching the live food with costly liposomes incorporating iodine rich oils.