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dc.contributor.advisorPosewitz, Matthew C.
dc.contributor.authorJinkerson, Robert Edward
dc.date.accessioned2007-01-03T06:17:33Z
dc.date.accessioned2022-02-09T08:58:06Z
dc.date.available2007-01-03T06:17:33Z
dc.date.available2022-02-09T08:58:06Z
dc.date.issued2014
dc.date.submitted2014
dc.identifierT 7505
dc.identifier.urihttp://hdl.handle.net/11124/418
dc.description2014 Spring.
dc.descriptionIncludes illustrations (some color).
dc.descriptionIncludes bibliographical references (pages 182-214).
dc.description.abstractThe saccharification of starch coupled with fermentation to ethanol and the transesterification of vegetable oils to produce biodiesel are mature technologies that currently provide the majority of biofuels in the United States. However, traditional food-based starch and oil feedstocks, such as corn and soybean, cannot meet our current fuel demands and their use remains controversial. Microalgae have been of recent interest for use as a biofuel feedstock because they can produce large quantities of carbohydrates and lipids, contain little recalcitrant biomass, and do not impact the food supply. In the green alga Chlamydomonas reinhardtii, the primary carbohydrate produced is starch and the primary storage lipid produced is triacylglyceride (TAG), but high yields of these bioenergy carriers are usually only found under conditions of nutrient stress (N, S, P). As a strategy for increasing TAG yields, starchless mutants that divert carbon away from starch biosynthesis and into TAG production were investigated. These starchless mutants produce more TAG than wildtype, but at the expense of total productivity and lower overall anabolic activity. To increase starch levels, a native enzyme key to starch biosynthesis, isoamylase 1 (ISA1), was introduced into these algae which resulted in starch excess phenotypes. These mutant strains accumulate 3 to 4 fold more total glucan under nutrient-replete conditions by diverting metabolic flux into starch biosynthesis at the expense of cell division and protein synthesis. The starches produced by these algae are more crystalline and larger in size than wildtype. None of the current genetically-tractable model algal species are competitive TAG production strains. To alleviate this the commercially cultivated, oleaginous alga Nannochloropsis gaditana CCMP526 was developed into a new model algal species for investigating TAG production. The genome and transcriptome was sequence and assembled, gene models developed, and metabolic pathways in this organism were reconstructed. Phylogenomic analysis identified genetic attributes of this organism, including gene expansions and unique stramenopile photosynthesis genes, that may explain the distinguishing oleaginous phenotypes observed. The availability of a genome sequence and transformation method are facilitating investigations into N. gaditana lipid biosynthesis and will permit genetic engineering strategies to further improve this naturally productive algal strain.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2014 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectNannochloropsis
dc.subjecttriacylglyceride
dc.subjectstarch
dc.subjectalgae
dc.subjectbiofuel
dc.subjectChlamydomonas
dc.subject.lcshBiomass energy
dc.subject.lcshMicroalgae
dc.subject.lcshSystems biology
dc.subject.lcshMetabolism
dc.titleMetabolic engineering and systems biology for increasing biofuel production in microalgae
dc.typeText
dc.contributor.committeememberLiberatore, Matthew W.
dc.contributor.committeememberWilliams, S. Kim R.
dc.contributor.committeememberVoorhees, Kent J.
thesis.degree.nameDoctor of Philosophy (Ph.D.)
thesis.degree.levelDoctoral
thesis.degree.disciplineChemistry and Geochemistry
thesis.degree.grantorColorado School of Mines


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