Theses and Dissertations at Montana State University (MSU)
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Item Algal biofilms and lipids: bicarbonate amendment and nitrate stress to stimulate lipid accumulation in algal biofilms(Montana State University - Bozeman, College of Engineering, 2022) Rathore, Muneeb Soban; Chairperson, Graduate Committee: Brent M. Peyton; This is a manuscript style paper that includes co-authored chapters.Algal biofuels are compounds obtained by transesterification of algal lipids to fatty acid methyl esters (FAMEs) which can be used as biodiesel. Algal biofilms have a potential for commercial applications of algal biomass for biofuel production and provide concentrated biomass requiring less water removal to reduce biofuel production costs. Lipid production in algal biofilms is low as compared to planktonic algal growth systems and strategies for enhancing lipid content in algal biofilms need to be developed. The overarching goal of the studies presented herein was to develop lipid accumulation strategies in algal biofilms using nutrient stresses to increase triacylglycerides (TAGs) and FAMEs. First, a reactor was designed for photoautotrophic biofilm growth incorporating a novel algal biomass harvesting mechanism. Chlorella vulgaris biofilm growth was demonstrated to establish the reactor characteristics under three different inorganic carbon regimes and the presence of excess calcium to facilitate biofilm attachment and accumulation. Excess calcium resulted in precipitate formation and increasing ash content in biomass and caused difficulty in biofilm detachment. However, the highest biomass accumulation was observed in the bicarbonate and the bicarbonate with calcium treatments. Second, two different algal strains were tested for lipid accumulation under two nutrient conditions: nitrate limitation and bicarbonate addition. Algal strains included, an extremophilic freshwater diatom RGd-1, a Yellowstone National Park (YNP) isolate, and oleaginous chlorophyte C. vulgaris. High bicarbonate content at low nitrate concentration in the bulk medium provided the highest lipid accumulation as determined by Nile Red fluorescence and Gas Chromatography Mass Spectrometry (GCMS) analysis of extracted FAMEs (7-22 % wt/wt). For prevention of biomass loss and quick response to nutrient stresses to stimulate lipid accumulation, the growth medium was exchanged after initial biofilm accumulation and operated in batch mode. This was implemented to quickly introduce nutrient stresses using fresh medium to vary bicarbonate and nitrate concentrations as needed. Thus, the work presented here demonstrated enhanced lipid production in algal biofilms with nitrate stress and bicarbonate amendment is a viable strategy to increase lipid accumulation. Increased lipid content may help offset the cost for biodiesel production with more lipid product and lower processing requirements for water removal.Item Sequence stratigraphic framework of the late Devonian (Frasnian) Duperow Formation in western and central Montana(Montana State University - Bozeman, College of Letters & Science, 2019) Steuer, Christopher Johann; Chairperson, Graduate Committee: David W. BowenThe Late Devonian Duperow Formation in western and central Montana and it's equivalent lower Jefferson Formation, is comprised of shallow marine carbonate strata deposited on the western margin of North America. It has produced significant volumes of oil and natural gas in the Alberta and Williston basins where the sequence stratigraphic framework of the formation is well-documented. However, in western and central Montana, the Duperow remains largely understudied. Additionally, at Kevin Dome, in northwest Montana, the Duperow hosts a large naturally occurring carbon-dioxide (CO^2) accumulation which is a potential economic resource and an analog for CO^2 sequestration over geologic time scales. The goal of this study is to determine the facies relationships and sequence stratigraphic architecture of the Late Devonian Duperow Formation in western and central Montana. This interpretation could help in exploration for oil and natural gas and provide useful information to aid in future carbon sequestration efforts. Multiple data sets are used in this study to best constrain depositional environments on the platform during Duperow deposition. Seven measured sections, three drill cores with associated well-logs, and forty-one thin sections are used to characterize facies, facies associations, parasequences, parasequence sets and sequences of the Duperow Formation and to construct the sequence stratigraphic framework within which these strata occur. Ten lithofacies comprising six lithofacies associations allow the interpretation of six depositional environments responsible for deposition of the Duperow Formation. The Duperow thins from the west and north onto the Central Montana Uplift, a paleohigh at the time, and thickens into the Central Montana Trough, a sub-basin on the platform. Two 2nd order and seven 3rd order sequences are interpreted from measured sections. Sequences are comprised of a transgressive systems tract and a highstand systems tract with no evidence for lowstand strata on the shelf. Transgression across the Central Montana Uplift did not occur until after the basal sequence boundary of the upper 2nd order sequence. Prior to this transgression, sequences lapped out before reaching the Central Montana Uplift. Overall, the Duperow in central and western Montana exhibits retrogradational stacking and thus is part of the transgressive systems tract of a lower-order megasequence.Item Sodium bicarbonate amendment for enhanced astaxanthin production from Haematococcus pluvialis(Montana State University - Bozeman, College of Engineering, 2019) Erturk, Berrak; Chairperson, Graduate Committee: Brent M. Peyton; Christian Lewis and Brent M. Peyton were co-authors of the article, 'Sodium bicarbonate amendment for enhanced astaxanthin production from Haematococcus pluvialis' submitted to the journal 'Algal research' which is contained within this thesis.Haematococcus pluvialis is a freshwater green microalga that is widely considered to be the richest natural source of the high value carotenoid astaxanthin. The use of bicarbonate salts as a means of efficiently delivering inorganic carbon in microalgal cultivation is a relatively new concept and its application is continuously growing. Previous studies have largely focused on increasing the lipid content in microalgae via the use of high concentrations of sodium bicarbonate under nitrogen deplete culture conditions. Lipid accumulation is directly related to astaxanthin production as astaxanthin is dissolved and stored in lipid bodies in H. pluvialis. Because of this relationship in H. pluvialis, the effects of sodium bicarbonate addition on astaxanthin production was investigated in this study. Due to its complex life cycle, H. pluvialis is commonly cultivated in two stages called the 'green' and 'red' stage. Different approaches have been proposed in each stage to increase the astaxanthin production, namely by growing microalgae under nutrient-limited conditions or resuspending the cells into nutrient deplete conditions. In this study, H. pluvialis (UTEX 2505) was cultivated in stirred (120 rpm) batch reactors containing MES-Volvox medium with a 12 h:12 h light/dark cycle. Sodium bicarbonate (2.5 mM) was used as an additional inorganic carbon source in the green stage and 50 mM of sodium bicarbonate was used as a trigger mechanism to induce astaxanthin production in the red stage. Following the trigger, the astaxanthin accumulation rate increased from 0.13 mg L ^-1 day ^-1 to 0.64 mg L ^-1 day ^-1 with an astaxanthin concentration of 1.56 + or - 0.01 mg L ^-1 and 3.95 + or - 1.25 mg L ^-1 respectively. Whereas, an addition of 2.5 mM sodium bicarbonate at the green stage increased the final astaxanthin accumulation rate up to 2.12 mg L ^-1 day ^-1 and the astaxanthin concentration to 11.2 + or - 0.56 mg L ^-1. Increasing biomass in the green stage resulted in higher astaxanthin content at the end of the red stage. In addition to increasing the total astaxanthin content, 2.5 mM of sodium bicarbonate led to faster nitrogen utilization during the green stage. With this faster utilization of nitrogen, the cultures were grown with a one-stage cultivation approach, where the astaxanthin production occurred in continuous mode.Item Carbonate preservation of dinosaur eggs in the upper Cretaceous Anacleto Formation at Auca Mahuevo, Neuquen Basin, Argentina(Montana State University - Bozeman, College of Letters & Science, 2011) Anggraini, Niswatin Wahida; Chairperson, Graduate Committee: James G. SchmittPreservation of dinosaur eggs and footprints by precipitation of calcium carbonate in the Upper Cretaceous Anacleto Formation at Auca Mahuevo, Argentina represents a relatively unusual occcurence in the fossil record. Under normal condition, eggs are readily destroyed in sediments shortly after burial by physical, chemical, and biological processes. This study attempts to determine a preservational model for carbonate eggs by characterizing their mineralogical composition and microstructures using a variety of analytical instruments including petrographic microscope, cathodoluminesce (CL) microscope, X-ray powder diffraction (XRD) and field-emission scanning electron microscope (FEM) to characterize the composition and fabric of the fossilized eggs. Several textutal features have been observed in the carbonate eggs, including membrane, embryonic skin, spherulites, ooids, peloids, Microcodium, calcified filaments, and micrite. Microbial actvity is likely responsible for the formation of these microfabric features, facilitating calcium carbonate precipitation leading to exceptional preservation of eggs. Although microbial influence in the carbonate egg preservation has not been clearly elucidated, laboratory experiments by other workers provide an argument for the role of microbes in the precipitation of calcium carbonate. The rare preservation of egg contents in the Anacleto Formation have been linked to biological-mediated processes. This preservation also provides evidence for penecontemporaneous carbonate precipitation under subaerial conditions before significant burial.