Theses and Dissertations at Montana State University (MSU)
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Item Biocorrosion of copper by Oleidesulfovibrio alaskensis G20 biofilms in static and dynamic environments(Montana State University - Bozeman, College of Engineering, 2024) Keskin, Yagmur; Chairperson, Graduate Committee: Brent M. Peyton; Matthew Fields (co-chair); This is a manuscript style paper that includes co-authored chapters.This study presents a detailed examination of the intricate relationships between Oleidesulfovibrio alaskensis G20 and copper (101), emphasizing three interconnected perspectives: the kinetics of copper toxicity in three distinct media, the impact of surface finishing on microbiologically influenced corrosion (MIC), and the interaction of G20 biofilms and copper in CDC biofilm reactors. Initially, the study concentrates on the kinetic effects of copper toxicity on the growth of G20. The research meticulously quantifies the detrimental impact of different copper (II) concentrations (6, 12, 16, and 24 micron) on bacterial growth kinetics in three media: LS4D balanced (BAL), electron acceptor-limited (EAL), and electron donor-limited (EDL). Using a non-competitive inhibition model, I50 (concentrations of copper causing 50% inhibition of bacterial growth) values were calculated to be 13.1, 13.87, and 11.31 micron for LS4D BAL, EAL, and EDL media, respectively. The second part of the study shifts its focus to the effect of surface finishing on MIC of copper 101 by G20. The biofilm and corrosion pit depths were measured through a series of sophisticated analyses employing 3D optical profilometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), and X-ray Diffraction Analysis (XRD). The research investigates how different levels of surface roughness, applied through metallographic grinding and polishing, influence corrosion. The findings demonstrate a clear pattern of both uniform and pitting corrosion across all surface finishes. Notably, a statistically significant decrease in corrosion rates was observed when the surface roughness of copper was altered from approximately 13?m to about 0.06?m. Finally, the study explores the interaction between G20 biofilms and copper (101) into CDC reactors to understand biofilm development on copper surfaces and its subsequent impact on copper corrosion in a dynamic environment over periods of 7, 9, and 14 days. The results showed robust biofilm formation through hexose and protein analyses and SEM images displaying progressive increases in SRB cell accumulation over time. Localized pit depths were measured and compared to static conditions, and pits showed only a 20% increase in a dynamic environment. These findings offer an improved understanding of the complex interactions between G20 and MIC of copper.Item Characterization of manganese sulfide inclusion surfaces in 1018 carbon steels and interfacial studies of graphene coated copper surfaces(Montana State University - Bozeman, College of Letters & Science, 2021) Rieders, Nathaniel Frederic; Co-chairs, Graduate Committee: Recep Avci and Yves U. IdzerdaManganese sulfide inclusions are known to be sites of localized corrosion in steels, however little is know concerning the physical and chemical properties of inclusion surfaces. Some inclusions have been observed to be more corrosively active than others. In an effort to distinguish between active and inactive inclusions, this work utilizes surface sensitive electron spectroscopies and microscopies to characterize manganese sulfide inclusion interfaces in 1018 carbon steels. A method was developed to measure variations in surface potential with a high degree of spatial resolution using an Auger microscope. It was found that manganese sulfide inclusion surfaces are heterogeneous and possess discrete manganese oxide and copper sulfide phases. Valence band Auger spectroscopy was used to distinguish between various Mn and Fe chemical species. Surface potential measurements indicate that inclusions are more noble than the surrounding steel surface. TEM analysis indicates a high defect content at the inclusion/steel interface. It is hypothesized that active and inactive inclusions can be distinguished via the availability of sulfur. Graphene on copper surfaces were characterized for use as a protective coating against corrosion using surface sensitive spectroscopies. A feature in the copper Auger transition was found to be unique to graphene, and used to identify its presence and degree of substrate coupling. Localized oxidation of the copper substrate was observed to correlate with low surface potential regions, believed to be intercalated oxygen, which enhances the reactivity of the graphene overlayer. Intercalated Cl was observed to inhibit substrate oxidation, and reduce the reactivity of the graphene overlayer. The intercalation of water was observed to occur at room temperature, and molecularly adsorb to the copper surface at temperatures up to 200 C, indicating that graphene inhibits dissociation of water. Distribution of intercalated water was observed using Auger spectroscopy. It is suggested that doping of graphene is an effective strategy for use as an anticorrosive coating on heterogeneous surfaces.Item Biochemical characterization of the six-transmembrane epithelial antigen of the prostate family of metalloreductases(Montana State University - Bozeman, College of Letters & Science, 2015) Kleven, Mark Daniel; Chairperson, Graduate Committee: C. Martin Lawrence; George H. Gauss was the main author, and Mark D. Kleven, Anoop K. Sendamarai, Mark D. Fleming and C. Martin Lawrence were co-authors of the article, 'The crystal structure of six-transmembrane epithelial antigen of the prostate 4 (Steap4), a ferri/cuprireductase, suggests a novel interdomain flavin-binding site' in the journal 'Journal of biological chemistry' which is contained within this thesis.; Mark D. Fleming and C. Martin Lawrence were co-authors of the article, 'Characterization of a single B-type heme, FAD and metal binding sites in the transmembrane domain of six trans-membrane epithelial antigen of the prostate (Steap) family proteins' submitted to the journal 'Journal of biological chemistry' which is contained within this thesis.Iron and copper are the two most abundant transition metals in humans and are mediators of many essential cellular processes. The entry of these metals into cells require controlled processes, including their reduction prior to uptake. A group of integral membrane enzymes, the six-transmembrane epithelial antigen of the prostate (Steap) family, are able to perform this function. Steap3, in particular, functions as the primary ferric reductase in the transferrin cycle, the dominant mode of erythrocyte iron uptake. How these enzymes perform these functions has remained ill-defined. Here, the biochemical underpinnings of Steap metalloreductase activity have been investigated. To elucidate these mechanisms, expression systems for Steap3 and Steap4 have been developed in bacterial, insect, and human cell lines and purified to varying degrees. By analyzing the truncated cytoplasmic oxidoreductase domain of Steap4, it was found that NADPH is oxidized by transferring a pair of electrons to a flavin. With this truncation, however, flavin only binds weakly and the construct shows no ability to preferentially bind one type of flavin. In contrast, when the full length Steap3 was partially purified, it exhibits high-affinity FAD-binding, indicating that the transmembrane region of the protein contains the major structural features of the FAD binding site. Further, it was found that the cytoplasm-oriented loops between transmembrane helices formed the site. The next cofactor in the electron transport chain is a single b-type heme. Two strictly conserved histidines were identified that coordinate the heme and both are required for heme incorporation. The metal binding site at the extracellular face of the membrane was also characterized. Here, it was found that Steap3 and Steap4 share a conserved high-affinity iron binding site. Additionally, iron and copper both bind with similar affinities to Steap4. Two critical residues of the metal binding site were determined and their predicted proximity to the heme cofactor suggests that the electron is transfer is direct between cofactor and metal. Finally, it was found that Steap's are able to dimerize in the cells, forming homo- and heterodimers Together, the enzymatic mechanism has been characterized in-depth for the first time for these physiologically-significant enzymes.Item Wetlands and copper concentrations across a headwater catchment impacted by acid rock drainage(Montana State University - Bozeman, 2000) Novak, Tracy M. Knoop; Chairperson, Graduate Committee: Paul HookItem Spatial pattern in the influence of sulfur dioxide emissions from Arizona and New Mexico copper smelters(Montana State University - Bozeman, College of Letters & Science, 1989) Adkison, Milo DouglasItem Copper injury of Escherichia coli(Montana State University - Bozeman, College of Agriculture, 1984) Domek, Matthew JosephItem Variation of the resistance of copper with potential energy of deformation(Montana State University - Bozeman, College of Letters & Science, 1946) Kerttula, Walter T.Item Expression and characterization of copper-containing proteins: galactose oxidase and tyrosinase(Montana State University - Bozeman, College of Letters & Science, 2002) Kamlin, Ejan MarieItem Isolation, characterization and copper binding of Gaeumannomyces graminis var. graminis melanin mutants(Montana State University - Bozeman, College of Agriculture, 1997) Frederick, Barbara AnneItem Recovery of copper by biopolymer gel and polymer vegetation by electrowinning and ion exchange technologies(Montana State University - Bozeman, College of Engineering, 1995) Kallepalli, Ramakrishna RajuBiopolymer gel beads of calcium alginate and alginic acid have high affinities for divalent metal ions such as Cu 2+. Hence they may be useful materials for recovering copper from aqueous solutions. The copper sorbed by the calcium alginate gel beads could be completely eluted and the metal recovered in a salable metallic form by using a combination of ion-exchange and electrowinning technologies. In such processes, the calcium alginate gel beads are fully regenerated. The resorption capacity of the gel beads did not decrease significantly during up to three sorption-desorption-electrowinning cycles. Distribution ratios of copper between the gel and liquid phases were measured using a batch method. Distribution ratios of copper for gel beads of calcium alginate ranged from 0.3 to 0.9 liter solution/gram dry sodium alginate [(mg Cu 2+ / gram dry sodium alginate)/(mg Cu 2+ / liter solution)]. Distribution ratios of copper for gel beads of alginic acid ranged from 0.47 to 0.84 liter solution/gram dry sodium alginate [(mg Cu 2+ / gram dry sodium alginate)/(mg Cu 2+ / liter solution)]. The equilibrium data were consistent with the ion-exchange reaction between cupric ions and calcium alginate/alginic acid. Maximum sorption capacities of the gel beads of calcium alginate and alginic acid were determined by comparing the experimental data with theoretical predictions. Maximum sorption capacities of the gel beads were found to be 5.21 X 10 -3 kmol/ kg dry sodium alginate and 4.11 X 10 -3 kmol/ kg dry sodium alginate for calcium alginate and alginic acid respectively. 3.2% sodium alginate in water was used to make the gel beads of calcium alginate and alginic acid. Scale up of the technology was studied in a fluidized bed reactor and electrowinning cell designed for this purpose. Calcium alginate gel beads were reused up to three times for absorption of copper after regeneration using ion exchange and electrowinning technologies. This technology reduced the influent copper concentration by 63%.