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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Immobilized mediator electrodes for microbial fuel cells

Godwin, Jonathan M 17 August 2011 (has links)
With the current interest in alternative methods of energy production and increased utilization of existing energy sources, microbial fuel cells have become an important field of research. Microbial fuel cells are devices which harvest electrons from microorganisms created by their enzymatic oxidation of complex carbon substrates or consumed by their reduction of chemical oxidants. Microbial fuel cells with photosynthetic biocathodes are of particular interest due to their ability to simultaneously produce electricity and hydrocarbons while reducing carbon dioxide. Most species of microorganisms including many bacteria and yeasts require exogenous electron transfer mediators in order to allow electron transfer with an electrode. While adding such chemicals is simple enough at a lab scale, problems arise with chemical costs and separation at a larger scale. The goal of this research was to develop electrodes composed of a robust material which will eliminate the need for added soluble electron mediators in a photosynthetic biocathode microbial fuel cell. Electrodes made from stainless steel 304L have been coated in a conductive polymer (polypyrrole) and an immobilized electron transfer mediator (methylene blue) and tested chemically for stability and in a microbial fuel cell environment for use in bioanodes and biocathodes. The use of these immobilized mediator in the photosynthetic biocathode increased the open circuit voltage of the cell from 0.17 V to 0.24 V and the short circuit current from 8 mA/m2 to 64 mA/m2 (normalized to the geometric surface area of the electrode) when compared to using the same mediator in solution. The opposite effect was seen when using the electrodes in a bioanode utilizing Saccharomyces cerevisiae. The open circuit voltage decreased from 0.37 V to 0.31 V and the short circuit current decreased from 94 mA/m2 to 24 mA/m2 when comparing the immobilized mediator to soluble mediators. The impact of the membrane and pH of the anode and cathode solutions were quantified and were found to have much less of an effect on the internal resistance than the microbial factors.
72

Selected proteolytic and amylolytic enzymes and their effect on Chlorella pyrenoidosa

Swendsen, David Adolph 03 June 2011 (has links)
Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.
73

Influences of a fluorescent brightener, as a medium component, upon the productivity of chlorella pyrenoidosa

Anderson, Robert N. 03 June 2011 (has links)
Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.
74

Développement d'un biocapteur conductimétrique bi-enzymatique à cellules algales

Chouteau, Céline Chovelon, Jean-Marc Durrieu, Claude. January 2005 (has links)
Thèse doctorat : Sciences et Techniques du Déchet : Villeurbanne, INSA : 2004. / Titre provenant de l'écran-titre. Bibliogr. p. 161-171.
75

Effets du cuivre sur l'ultrastructure de scenedesmus quadricauda et chlorella vulgaris en relation avec l'acquisition de tolérance /

Bastien, Christian, January 1986 (has links)
Mémoire (M. Sc. pures)--Université du Québec à Chicoutimi, 1986. / Document électronique également accessible en format PDF. CaQCU
76

Aggregation von Mikroorganismen /

Eppler, Birgit. January 1981 (has links)
Universiẗat, Diss., 1980 u.d.T.: Eppler, Birgit: Aggregation von Bacillus cereus und Chlorella vulgaris in Gegenwart von Natriumionen und Kalziumionen--Karlsruhe.
77

Evaluation of nutritional value and activity of green microalgae Chlorella vulgaris in rats and mice

Janczyk, Pawel. January 1900 (has links)
Freie Universiẗat, Diss., 2005--Berlin. / Dateiformat: zip, Dateien im PDF-Format. Erscheinungsjahr an der Haupttitelstelle: 2005.
78

EVALUATING ALGAL GROWTH AT DIFFERENT TEMPERATURES

Cassidy, Keelin Owen 01 January 2011 (has links)
In recent years, there has been a concern for the amount of carbon dioxide released into the atmosphere and how it will be captured. One way to capture carbon dioxide is with algae. In this study, algae's growth was measured at different temperatures. The first part of the study was to grow Scenedesmus and Chlorella with M8 or urea growth media at a temperature of 25, 30 or 35ºC. It was found that 30ºC had the best growth rates for both algae. The second part studied Scenedesmus growth with urea, more in-depth, and found the optimum growth temperature to be 27.5ºC with a growth rate of 0.29 1/hr. The last part of the study was a heat transfer model which predicted the temperature of a greenhouse and an outdoor unit. The model could also predict the growth rate of the algae and the temperature if flue gas is mixed in with the algae.
79

Vliv zkrmování řas na vybrané kvalitativní ukazatele mléka malých přežvýkavců / Effect of algae feeding on selected qualitative indicators of milk of small ruminants

Novotná, Klára January 2015 (has links)
Milk fat is one of the most important components of goat milk. Another benefit of goat milk fat is its better digestibility in comparison with cow milk, which is caused by the smaller size of lipid micelles. Goat milk fat contains more lower fatty acids (caproic, caprylic and capric), which affect the production and processing of milk and cause specific flavor of goat's milk and dairy products. In recent years, the subject of many studies the possibility of increasing the content of other health beneficial fatty acids in goat milk, such as conjugated linoleic acid (CLA) and omega-3 and omega-6 polyunsaturated fatty acids. Animal nutrition is a significant factor how to achieve these changes in the fatty acid profile of milk fat. For these purposes can be used as additives for certain species of algae which are the source of nutritionally valuable lipids with a high content of polyene fatty acids, especially omega-3 and omega-6 fatty acids. The ability to change the composition of goat mikl fat, represents an opportunity for the development of new products. Functional foods, such as milk and dairy products enriched with omega-3 and omega-6 fatty acids. The aim of this work is to determine what effect the addition of selected algae (Chlorella vulgaris and Japanochytrium sp.) On milk production and representation of the components of milk, focusing on the composition of milk fat and fatty acid profile in goat milk. Attention was paid to reduction of saturated and increase the proportion of nutritionally beneficial unsaturated fatty acids, in particular n-3 polyunsaturated fatty acids.
80

Cultivo da microalga Chlorella vulgaris em efluentes aquícolas e sua influência na concentração lipídica / Cultivation of microalgae Chlorella vulgaris in aquaculture effluents and its influence on lipid concentration

Silva, Jose William Alves da January 2013 (has links)
SILVA, Jose William Alves da. Cultivo da microalga Chlorella vulgaris em efluentes aquícolas e sua influência na concentração lipídica. 2013. 48 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2013 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T13:04:18Z No. of bitstreams: 1 2013_dis_jwasilva.pdf: 918066 bytes, checksum: 3234978a89ce64bd0d1748d700d6c3a6 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T13:04:36Z (GMT) No. of bitstreams: 1 2013_dis_jwasilva.pdf: 918066 bytes, checksum: 3234978a89ce64bd0d1748d700d6c3a6 (MD5) / Made available in DSpace on 2016-07-18T13:04:36Z (GMT). No. of bitstreams: 1 2013_dis_jwasilva.pdf: 918066 bytes, checksum: 3234978a89ce64bd0d1748d700d6c3a6 (MD5) Previous issue date: 2013 / Microalgae can be used as feedstock for producing biofuels on a large scale, due to the ease of cultivation, strong growth rate, high content of fatty acids and higher productivity than other oils, making it an excellent alternative to fossil fuels. The study evaluated the use of microalgae Chlorella vulgaris in phytoremediation of aquaculture effluents and lipid evaluation. The microalgae was obtained in the algae bank Federal University of Ceará. Were three treatments with six replicates, using as culture medium Guillard f / 2 and effluents of shrimp and fish farming. Cultivation was batch containers of 12 L and was observed daily by spectrophotometry at 680 nm, and determining the concentration of ammonia, nitrite, nitrate and phosphorus performed at the beginning, middle and end of crops. The separation of the cells from culture medium was performed by chemical flocculation using NaOH 2N. After washing, the biomass was dried in an oven with renovation of air at 60 °C for 24 hours and then quantified. Trea tment with effluent was, as biomass production, significantly higher than the others, showing an average weight of 0.91 ± 0.05 g L-1 . The effluent removed satisfactorily nitrogen compounds with a 76% removal of these compounds. The cultivation performed with tilapia effluent showed better lipid productivity with 0.025 ± 0.002 g L -1 day -1. The microalga C. vulgaris can be used for phytoremediation of aquaculture effluent, biomass and lipids. / As microalgas podem ser utilizadas como matéria prima para a produção de biocombustíveis em larga escala, em decorrência da facilidade de cultivo, acentuada velocidade de crescimento, alto teor de ácidos graxos e produtividade maior que outras oleaginosas, sendo uma excelente alternativa aos combustíveis fósseis. O experimento avaliou a utilização da microalga Chlorella vulgaris na fitorremediação de efluentes aquícolas e sua produção lipídica. Foram realizados três tratamentos, com seis repetições cada, utilizando como meios de cultura o Guillard f/2 e efluentes da carcinicultura e piscicultura. O cultivo estacionário foi realizado em um recipiente com volume útil de 12 L e foi acompanhado, diariamente, por espectrofotometria a 680 nm, sendo a determinação das concentrações de amônia, nitritos, nitratos e fosfatos realizada no início, meio e fim dos cultivos. A separação das células do meio de cultivo foi realizada por floculação química, usando NaOH 2N e, depois de lavada, a biomassa foi seca em estufa com renovação de ar a 60 °C por 24 h. O tratamento com efluente da carcinicultura apresentou uma produção de biomassa significativamente maior que os demais, com valor médio de 0,91±0,05 g L-1. Os compostos nitrogenados presentes nos efluentes atingiram remoção média de 76%, resultado considerado satisfatório. O cultivo realizado com efluente de piscicultura apresentou melhor produtividade lipídica com 0,025 ± 0,002 g L-1 dia-1. Assim, a microalga C. vulgaris pode ser utilizada na fitorremediação de efluentes aquícolas para a produção de biomassa e extração de lipídios.

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