Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Lipid profiling, carbon partitioning, and inorganic carbon optimization to enhance growth and lipid accumulation in microalgae(Montana State University - Bozeman, College of Engineering, 2013) Lohman, Egan Jackson; Chairperson, Graduate Committee: Robin Gerlach; Robert D. Gardner, Luke Halverson, Richard E. Macur, Brent M. Peyton and Robin Gerlach were co-authors of the article, 'An efficient and scalable extraction and quantification method for algal derived biofuel' in the journal 'Journal of microbiological methods' which is contained within this thesis.; Robert D. Gardner, Luke Halverson, Brent M. Peyton and Robin Gerlach were co-authors of the article, 'Carbon partitioning in lipids synthesized by Chlamydomonas reinhardtii when cultured under three unique inorganic carbon regimes' submitted to the journal 'Applied phycology' which is contained within this thesis.; Robert D. Gardner, Todd Pedersen, Keith E. Cooksey, Brent M. Peyton and Robin Gerlach were co-authors of the article, 'An optimized inorganic carbon regime for enhanced growth and lipid accumulation in Chlorella vulgaris' submitted to the journal 'Biotechnology for biofuels' which is contained within this thesis.Microalgae are capable of accumulating high concentrations of lipids and other metabolites which can be used as precursor compounds for energy and valuable co-products. In order to fully exploit this resource, robust methods are needed to properly quantify and analyze the metabolites of interest. Additionally, understanding how and why these organisms synthesize these metabolites and developing optimized strategies for enhancing their metabolism is of paramount importance if algal biofuels and co-product development are to become commercially feasible. This dissertation represents the summary of work completed to develop analytical methods for quantifying lipid compounds synthesized by two Chlorophytes, Chlamydomonas reinhardtii sp. CC124 and Chlorella vulgaris UTEX 395, and the marine diatom Phaeodactylum tricornutum Pt-1. Additionally, C.reinhardtii was evaluated for factors that control and stimulate triacylglycerol (TAG) accumulation in microalgae by monitoring changes in lipid precursor compounds such as free fatty acids, mono- di- and tri-acylglycerides as well as fatty acids which were transesterified into fatty acid methyl ester (FAME); the bio-synthesized equivalent of diesel fuel. C. vulgaris was evaluated for optimized growth and lipid accumulation on various inorganic carbon substrates. This work resulted in a commercially applicable, two-phase growth/lipid accumulation regime which uses low grade sodium bicarbonate as the inorganic carbon substrate to enhance both growth and lipid accumulation and reduce the cost and resource overhead associated with using only carbon dioxide as the sole inorganic carbon source.Item Lipid production in algae stressed with sodium bicarbonate and sodium chloride(Montana State University - Bozeman, College of Engineering, 2013) Blaskovich, John Philip; Chairperson, Graduate Committee: Brent M. Peyton; Rob Gardner, Egan Lohman, Karen Moll, Luke Halverson, Robin Gerlach, Brent Peyton were co-authors of the article, 'The use of sodium bicarbonate and sodium chloride to stimulate lipid production in an algal isolate from Soap Lake, Washington' submitted to the journal 'Algal research' which is contained within this thesis.Microalgae may play an important role in the path to a more sustainable future by producing valuable hydrocarbons using inorganic carbon, sunlight, and non-food source competitive supplies of nitrogen and phosphorus. The prospect of growing microalgae for the production of a stable and dependable source of biofuel is plausible only if done at scale with intricate attention applied to the biochemistry, geochemistry, and environmental conditions of each system. Extreme environments with low proton activity and high salinity conditions may harbor microalgae suitable for large scale outdoor cultivation. Several algal isolates native to Soap Lake in Washington State were screened for biofuel potential and three isolates were selected for further studies. These three isolates were characterized to assess impacts on biofuel production studying high ionic strength in the form of sodium chloride (NaCl) in excess of 18g/L, and carbon supplemented treatments through the addition of inorganic carbon in the form of sodium bicarbonate (NaHCO 3). Further, the ability of NaHCO 3 and NaCl to trigger lipid production was determined. The study was centered on understanding differences between two factors that will likely have implications in large-scale algal raceway ponds: inorganic carbon limitation, speciation, or bioavailability, and evaporative conditions resulting in high concentrations of salt. In this study, cell concentration, cell dry weight, nitrate, pH, biofuel potential, extractable lipid potential, and DIC (dissolved inorganic carbon), were monitored over time. Isolate GK5La grown in standard medium had the highest concentration of cell dry weight at the end of the study. Cultures supplemented with sodium bicarbonate were determined to be the most efficient way to produce biofuel in the form of extractable lipids. Supplementation with sodium bicarbonate and spiking to a concentration of 18g/L sodium chloride showed to be the most productive way to make triacylglyceride (TAG). Fatty acid methyl ester (FAME) production on a concentration basis was greatest in the control treatment grown in standard medium.