Browsing by Subject "algae"
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Item Algal biofuels : the effect of salinity and pH on growth and lipid content of algae(2009-08) Gutierrez, Cesar Carlos; Marshall, Jill Ann; Sathasivan, Kanagasabapathi; Mehdy, Mona Cynthia, 1955-Supplies of nonrenewable fossil fuels are becoming more limited even as they continue to contribute to pollution and economic concerns. Alternative sources of energy must be developed that help minimize these problems. One potential source of energy is the production of biofuels from algae. Here we evaluate algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. In particular, we examine the effects of salinity and pH on the growth and lipid content of the algae. Samples of algae from the ponds exhibited high levels of growth and lipid production at a salinity of 9 ppt and pH 7. These conditions are similar to the natural conditions of the ponds, indicating that they may be a good source of algal biofuels.Item Algal biofuels : the effect of temperature on algal growth and lipid content(2009-08) Klenzendorf, Stephanie Marie; Marshall, Jill Ann; Mehdy, Mona Cynthia, 1955-; Sathasivan, KanagasabapathiReplacing fossil fuels with algae, a renewable resource, is an exciting possibility. This study evaluates the algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. Samples of algae from these ponds were cultured at varying temperatures ranging from 15.5ºC to 36.5ºC. High levels of growth were observed at 20.5ºC and the highest lipid content was measured at 23.0ºC. Temperature was also a factor in the distribution of microalgal taxa throughout the temperature gradient. This information will be added to the growing body of research investigating similar cultures of algae for future biofuel production.Item Design and Analysis of Flexible Biodiesel Processes with Multiple Feedstocks(2011-10-21) Pokoo-Aikins, Grace AmarachukwuWith the growing interest in converting a wide variety of biomass-based feedstocks to biofuels, there is a need to develop effective procedures for the design and optimization of multi-feedstock biorefineries. The unifying goal of this work is the development of systematic methodologies and procedures for designing flexible multifeedstock biorefineries. This work addresses four problems that constitute building blocks towards achieving the unifying goal of the dissertation. The first problem addresses the design and techno-economic analysis of an integrated system for the production of biodiesel from algal oil. With the sequestration of carbon dioxide from power plant flue gases, algae growth and processing has the potential to reduce greenhouse gas emissions. Algae are a non-food oil feedstock source and various pathways and technologies for obtaining algal oil were investigated. Detailed economic and sensitivity analysis reveal specific scenarios that lead to profitability of algal oil as an alternative feedstock. In the second problem, a new safety metric is introduced and utilized in process design and selection. A case study was solved to assess the potential of producing biodiesel from sewage sludge. The entire process was evaluated based on multiple criteria including cost, technology and safety. The third problem is concerned with incorporating flexibility in the design phase of the development of multi-feedstock biofuel production processes. A mathematical formulation is developed for determining the optimal flexible design for a biorefinery that is to accommodate the use of multiple feedstocks. Various objective functions may be utilized for the flexible plant depending on the purpose of the flexibility analysis and a case study is presented to demonstrate one such objective function. Finally, the development of a systematic procedure for incorporating flexibility and heat integration in the design phase of a flexible feedstock production process is introduced for the fourth problem. A mathematical formulation is developed for use in determining the heat exchange network design. By incorporating the feedstock scenarios under investigation, a mixed integer linear program is generated and a flexible heat exchange network scheme can be developed. The solution provides for a network that can accommodate the heating and cooling demands of the various scenarios while meeting minimum utility targets.Item Electrolytic Methods as a Cost and Energy Effective Alternative of Harvesting Algae for Biofuel(2012-08-30) Morrison, Taylor 1986-Process variables of electrolytic technology to reduce the energy consumption of harvesting Nonnocloropsis salina were investigated including electro-coagulation, electro-floatation, and electro-flocculation. Electro-coagulation and electro-flocculation showed significant cost savings, however electro-floatation did not. The objectives were to determine the effects of electrode material, pH adjustment and electro-polymer addition for electro-coagulation and determine the performance characteristics for electro-coagulation and electro-flocculation. Both treatments proved to be competitive with the energy consumption of a centrifuge. The best electrolytic treatments were electro-coagulation with aluminum and nickel electrodes. Energy requirements at optimum conditions were 239 and 344 kWh/ton. The best treatment combination using electro-flocculation was 432 kWh/ton with no electrode consumption, which could lead to potential cost savings.Item Factors influencing algal biomass in hydrologically dynamic salt ponds in a subtropical salt marsh(2009-05-15) Miller, Carrie J.The interface between land and water is often a dynamic zone that responds to relatively short-term climatic and hydrologic forces. Coastal salt marshes occupy this zone between land and sea and typically are comprised of vegetated marsh intersected by channels and shallow ponds that are subject to flooding by winds, tides, and storm surges. Coastal salt marshes are widely regarded as zones of high macrophyte productivity. However, microalgae may contribute more to salt marsh productivity than previously realized, underscoring the importance of understanding algal dynamics in such systems. Benthic and planktonic chlorophyll-a (surrogate for total algal biomass), sediment AFDW, total suspended solids, salinity, and nutrients were examined in marsh ponds in the subtropical Guadalupe Estuary, TX, USA to determine the effects of hydrologic connections on algal biomass in this system. From May 2005 ? May 2006 there were several pond connection, disconnection, and desiccation events. During periods of disconnection, algal biomass was higher in both the benthos and the water column than during connection events when supposed flushing occurred. Connection events also flushed out high NH4 accumulating in pond surface waters, but did not increase NOx. Therefore, the primary source of DIN seemed to be nutrient cycling within the ponds. There was a temporal effect on surface water salinity, which increased throughout the sampling period as bay water levels and subsequent pond connections decreased, demonstrating interannual variability and the link between seasons (wet vs. dry) and marsh inundation patterns (high water periods vs. low water periods) in this estuary.Item Probing the Roles that Intraflagellar Transport B Protiens Play on Stability, Assembly, and Localization of Complex B in Chlamydomonas ReinhardtII(2012-11-07) Richey, ElizabethIntraflagellar transport (IFT), the key mechanism for ciliogenesis, involves large protein particles moving bi-directionally along the entire ciliary length. IFT particles contain two large protein complexes, A and B, which are constructed with proteins in a core and several peripheral proteins. Prior studies have shown that in Chlamydomonas reinhardtii, IFT46, IFT52, and IFT88 directly interact with each other and are in a subcomplex of the IFT B core. However, ift46, bld1, and ift88 mutants differ in phenotype as ift46 mutants are able to form short flagella, while the other two lack flagella completely. In this study, we investigated the functional differences of these individual IFT proteins contributing to complex B assembly, stability, and basal body localization. We found that complex B is completely disrupted in bld1 mutant, indicating an essential role of IFT52 for complex B core assembly. Ift46 mutant cells are capable of assembling a relatively intact but highly unstable complex B. In contrast, in ift88 mutant cells the complex B core still assembles and remains stable, but the peripheral proteins no longer attach to the B core. Moreover, while complex A and the anterograde IFT motor FLA10 are localized normally to the transition fibers, complex B proteins instead are accumulated at the proximal ends of the basal bodies in ift88. Taken together, these results revealed a step-wise assembly process for complex B, and showed that the complex first localizes to the proximal end of the centrioles and then translocates onto the transition fibers via an IFT88-dependent mechanism. Protein interaction analyses such as the yeast two-hybrid assay in addition to identification and characterization of novel IFT complex B mutants will reveal a more complete picture of the architecture and function of IFT complex B.