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dc.contributor.authorRamos, Anaen
dc.date.accessioned2018-05-31T19:22:49Z
dc.date.available2018-05-31T19:22:49Z
dc.identifier.urihttp://hdl.handle.net/1974/24267
dc.description.abstractMicroalgae are photosynthetic microorganisms that can grow in a variety of environments. They have become a popular feedstock for the production of biofuels, high-value chemicals, and nutraceuticals. One of the main products obtained from microalgae is biodiesel: a mix of fatty acid methyl esters (FAMEs) obtained from the transesterification of triacylglycerol (TAG). However, microalgal biodiesel still cannot compete economically with petroleoum diesel. Therefore, the objective of this thesis was to explore alternatives to make microalgal cultivation for biodiesel more efficient. Microalgal treatment of municipal wastewater has been discussed as a strategy for the simultaneous removal of excess nutrients and the generation of microalgal biomass. This thesis evaluated the performance of Scenedesmus sp. and Chlorella sorokiniana in the removal of nutrients from non-sterile, highly concentrated synthetic-wastewater. These microalgae removed up to 60% NH4+ and 44% PO43- in a semi-continuous cultivation mode without negatively affecting effluent quality, demonstrating that microalgal growth can be coupled with wastewater treatment. Microalgal research is growing, and efforts to enhance TAG production are the focus of many studies. Reliable genetic modification protocols for many species, such as Chlorella vulgaris, are still not available. Therefore, work with the model Chlamydomonas reinhardtii is a practical alternative for proof-of-concept studies. The work in this thesis generated five Chlorella vulgaris starch mutants through UV-mutagenesis: four low-starch producing and one starch-overproducer. Additionally, four Chlamydomonas reinhardtii transgenic lines expressing Chlorella vulgaris genes involved in glycerolipid metabolism were developed. Mutant st27, with lower starch production than wildtype, displayed up to 3.8-fold increase in TAG, illustrating the importance of the organic carbon source in the medium to provide enough carbon precursors for TAG biosynthesis. Similarly, the transgenic lines increased lipid content more than 100-fold, suggesting that increasing glycerol-3-phosphate availability is crucial to generate oleaginous feedstock. This thesis illustrates the possibility of generating microalgal strains rich in both starch and TAG, which would be a promising feedstock for microalgal biorefineries. Additionally, two new gene candidates to improve TAG yields in microalgal strains are suggested, expanding on the knowledge available for metabolic engineering of microalgal crops for biodiesel production.en
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectChlamydomonas Reinhardtiien
dc.subjectChlorella Vulgarisen
dc.subjectBiodieselen
dc.subjectGlycerolipid Metabolismen
dc.titleMicroalgae Cultivation on Wastewater and Genetic Modifications to Increase Triacylglycerol Productionen
dc.typethesisen
dc.description.degreePhDen
dc.contributor.supervisorRegan, Sharonen
dc.contributor.supervisorMcGinn, Patrick J.en
dc.contributor.departmentBiologyen
dc.embargo.termsThesis needs to be restricted because most chapters are in preparation for submission to scientific journals.en
dc.embargo.liftdate2023-05-31T16:59:06Z
dc.degree.grantorQueen's University at Kingstonen


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