Theses and Dissertations at Montana State University (MSU)
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Item The microbial community ecology of various systems for the cultivation of algal biodiesel(Montana State University - Bozeman, College of Letters & Science, 2017) Bell, Tisza Ann Szeremy; Chairperson, Graduate Committee: Matthew Fields; Bharath Prithiviraj, Brad D. Wahlen, Matthew W. Fields and Brent M. Peyton were co-authors of the article, 'A lipid-accumulating alga maintains growth in outdoor, alkaliphilic raceway pond with mixed microbial communities' submitted to the journal 'Frontiers in microbiology' which is contained within this thesis.; Emel Sen-Kilic, Tamas Felfoldi, Gabor Vasas, Matthew W. Fields and Brent M. Peyton were co-authors of the article, 'Bacteria and eukarya community during eutrophication and toxic cyanobacterial blooms in the alkaline Lake Velence, Hungary' which is contained within this thesis.; Lakotah Doig, Brent M. Peyton, Robin Gerlach and Matthew W. Fields were co-authors of the article, 'Characterizing the microbial community and its intrinsic ability to produce algal biodiesel in wastewater treatment lagoons' which is contained within this thesis.Algal based biofuel has the potential to aid in offsetting future fossil fuel consumption and demand, and lowering CO 2 emissions. Cultivation strategies are a pivotal component of achieving high biomass yield. Open outdoor pond systems are currently the most economically viable method for large-scale algae cultivation due to less energy for maintenance than closed systems. However, open pond cultivation is subject to microbial colonization, sometimes negatively impacting the algal crop. Thus, large-scale production is hindered by gaps in our fundamental understanding of microbial interactions and ecology. The following research aims to explore the interplay between cultivation methods, nutrient availability, community composition, lipid metabolism, and system ecology and identify cost effective concepts for algal lipid production. Using alkalinity to limit microbial colonization of an open system is investigated in Chapter 2 in which a monoculture of Chlorella vulgaris was successfully cultivated. A putative relationship with a Pseudomonas sp. was identified in which the exchange of key metabolites could have enhanced algal growth and limited contamination. Such interactions may minimize the need for pesticides and fertilizer subsequently reducing pollution and operating costs. Findings suggested that potentially beneficial algal-bacterial relationships occurring in alkaline conditions supported a productive and stable monoculture. Alkalinity, in addition to nutrient abundance, is further explored in a natural freshwater terminal lake system, presented in Chapter 3. Lake eutrophication coupled with temperature increases led to a toxic cyanobacterial bloom that reduced overall eukaryotic diversity. Insight gained on the interplay between alkalinity, nutrients, and community dynamics from this natural system was then applied to a series of artificial wastewater lagoons Chapter 4. Elevated lipid (g/L) was observed in this system partially facilitated by increased water residence time in the lagoons and elevated nitrogen availability. Differing alga community composition were observed during periods of elevated lipid in addition to higher biomass (cells/mL) suggesting that higher lipid volumes were the result of high biomass concentration and not necessarily the lipid productivity of specific alga taxa. The research presented utilizes traditional ecologic concepts like diversity and contributes to a more comprehensive understanding of community interactions helping to minimize cost, reduce pollution, and ultimately contribute to the realization of viable biodiesel.Item Lipid accumulation in mixed photoautotrophic cultures from municipal wastewater(Montana State University - Bozeman, College of Letters & Science, 2016) Doig, Lakotah Dawn; Chairperson, Graduate Committee: Matthew Fields; Matthew W. Fields was a co-author of the article, 'Lipid accumulation in mixed photoautotrophic cultures from municipal wastewater' which is contained within this thesis.The growing consumption and need for sustainable forms of energy has spurred interest in biofuels and the feedstocks that offer possible solutions. Microalgae have emerged as a possible resource for the more sustainable production of biomass and biofuel, but nutrient and water demands offer challenges that limit large-scale biomass and biofuel production. Wastewater offers a potential solution to this issue as a low-quality but high-nutrient water source that could be exploited for the production of microalgal biomass. Many studies have successfully isolated or introduced algal monocultures into a wastewater environment for either lipid production or bioremediation purposes. However, recent studies have indicated increased lipid yields and nutrient removal with mixed cultures and algal consortia, but further work is needed to understand community dynamics and population networks that increase the niche landscape with compensatory interactions that promote desired functions (e.g., biomass and/or lipids) in a stable manner. This thesis seeks to explore the potential of a mixed photoautotrophic population that is currently being used to treat municipal wastewater (i.e., nutrient removal) for lipid producing capabilities and the impact of indigenous bacterial populations native to wastewater. In doing so we hoped to test the effects of increased biodiversity on lipid production at an interspecific level. Community dynamics, lipid profiles, and biomass productivities were monitored over a series of growth experiments utilizing filter-sterilized and non-sterile wastewater. The results from these experiments indicated substantial lipid production from communities grown in the presence of indigenous bacterial communities found in wastewater. These results suggest the prospect that wastewater possesses for biofuel production with mixed algal communities. It also indicates a more dynamic role of in situ community interactions in contributing to biomass and bio-oil accumulation of mixed algal communities.Item Diatom biofuels : optimizing nutrient requirements for growth and lipid accumulation in YNP isolate RGd-1(Montana State University - Bozeman, College of Letters & Science, 2012) Moll, Karen Margaret; Chairperson, Graduate Committee: Brent M. PeytonThe world's crude oil supply is decreasing at an alarming rate and no longer represents a long-term solution to meet energy needs. Development of renewable energy sources is required to meet transport fuel demands. Algal biofuels represent a potentially viable option. Diatom strain, RGd-1, isolated from Yellowstone National Park, produces high concentrations of lipids that can be used for biodiesel production. To increase cell numbers, RGd-1 was grown in six silica concentrations: without added silica, four silica concentrations within the soluble range (0.5-2mM), and one just above the soluble range (2.5 mM). Increasing the silica concentration resulted in an increase in total cell numbers and dry cell weight (DCW) with R ²=0.965. Silica depletion was verified by inductively coupled plasma mass spectrometry (ICP-MS). When grown in higher silica concentrations the medium reached a higher pH, which remained elevated. Nile Red fluorescence can be used as measurement of triacylglycerol (TAG). Once silica was depleted, Nile Red fluorescence increased. Unlike green algae and other diatoms, nitrate was never depleted when using the standard Bolds Basal Medium concentration (2.94 mM). RGd-1 never depleted nitrate from the growth medium and utilized only 1/3 of the original nitrate concentration (1 mM) by the time cells reached stationary phase. Therefore, the nitrate concentration was decreased to 1mM to induce a dual nitrate and silica stress. To increase the lipid content further, sodium bicarbonate was added to cells grown with each nitrate concentration (2.94 and 1 mM NO ₃-). Coupling nitrate limitation with sodium bicarbonate addition resulted in higher Nile Red fluorescence. RGd-1 fatty acids were primarily observed as C16:0, C16:1, C18:1-3 and C20:5, averaging at approximately 35, 30, 16 and 10%, respectively of the total lipid content. With exception of cells grown without added silica, the percent lipid content was approximately the same (30-40% (w/w) TAG (Triacylglycerol) and 70-80% (w/w) fatty acid methyl ester (FAME) grown under all conditions within the soluble range. However, when factoring in the dry cell weight from each system, it was observed that the TAG and FAME yields increased with silica concentration when normalized to DCW.