Theses and Dissertations at Montana State University (MSU)
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Item Bio-trapping ureolytic bacteria on sand to improve the efficiency of biocementation(Montana State University - Bozeman, College of Engineering, 2023) Ugur, Gizem Elif; Chairperson, Graduate Committee: Chelsea M. Heveran; Adrienne J. Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.Microbially induced calcium carbonate precipitation (MICP) has emerged as a novel biocementation technique for its potential solution to sustainable construction. Although current MICP approaches have made significant progress, achieving spatial control over biomineralization is challenging due to its complexity, which is affected by many factors, such as microorganisms, reaction kinetics, and environmental factors. Spatially controlling biomineralization for building or targeted repair of materials can significantly improve efficiency and sustainability while achieving desired outcomes. The purpose of this thesis was to assess whether biomineralization can be enhanced through surface pre-treatment of sand using amino silanes, such as 3-aminopropyl-methyl-diethoxysilane (APMDES), which is one form of spatial control of biomineralization through prescribing the location of the microbes. Moreover, a preliminary study was conducted to assess whether biomineralized sand, with and without the APMDES treatment, can be recycled and reused for biomineralization of subsequent generations. The impact of APMDES treatment on bacterial adhesion on sand, growth, and urease activity was analyzed. Biocementation efficiency was evaluated by comparing compressive strength and calcium gain of APMDES-treated sand with untreated sand. APMDES treatment promotes abundant and immediate trapping of bacteria on sand surfaces through increased electrostatic interaction that attracts negatively charged walls of bacteria to positively charged amine groups. While APMDES treatment compromises microbial viability, it preserves the urease enzyme for catalyzing urea hydrolysis. APMDES-treated sand achieved comparable strength with fewer bacterial injections compared to untreated sand. APMDES-treated sand biocemented using three injections of bacteria and cementation media gained the same strength as seven injections. Biomineral gain of APMDES-treated sand was similar compared to untreated sand, which shows calcium accrual in the structure may be influenced by additional factors, such as the distribution of calcite, differences in the calcite precipitation patterns, and morphology. Overall, incorporating APMDES treatment can potentially improve the efficiency and sustainability of MICP by spatially controlling biomineralization.Item Investigation of microbially induced carbonate precipitation for mitigation of acid mine drainage from coal mining waste(Montana State University - Bozeman, College of Engineering, 2023) Delwiche, Jenna Anne; Chairperson, Graduate Committee: Ellen G. Lauchnor; Adrienne J. Phillips (co-chair); This is a manuscript style paper that includes co-authored chapters.Acid Mine Drainage (AMD) is a serious environmental concern associated with coal mining. Many of the existing methods for addressing AMD are costly and focus on clean-up rather than prevention. In this study, the feasibility of using microbially induced carbonate precipitation (MICP) as an alternative method for mitigating environmental impacts from coal mining waste rock was investigated using laboratory scale experiments. Flow-through column testing showed that MICP can be used to create a calcium carbonate coating on coal waste rock, acting as a barrier between the rock and water. This treatment increased leachate pH, and microscopic inspection indicated that the presence of live bacteria was important for creating a durable coating. The MICP treatment decreased concentrations of heavy metals such as aluminum, barium, beryllium, copper, nickel, zinc, and iron in the leachate, but increased concentrations of vanadium, selenium, molybdenum, uranium, and arsenic. These results indicate that MICP may be an effective technique for mitigating AMD, but additional laboratory and field testing is needed to assess the feasibility of this treatment technology.Item Effect of bio-cementation on thermal properties of silty sand(Montana State University - Bozeman, College of Engineering, 2022) Gunyol, Pinar; Chairperson, Graduate Committee: Mohammad KhosraviIn recent years, there has been an increasing interest in the use of biological technologies in geotechnical engineering to improve thermal properties of geomaterials. Urea hydrolysis is a chemical reaction which can generate favorable conditions that result in the precipitation of calcium carbonate. Certain microbes or plant sources produce the urease enzyme which catalyzes the hydrolysis of urea to form carbonate (CaCO 3) to bond soil particles. Cementation located between the grain particles acts as a highly conductive heat transfer path by increasing the contact area between the sand particles. In this thesis, the applicability of bio-cementation via microbially induced calcite precipitation (MICP) on silty sand specimens with different fines contents of 0%, 5%, and 15% were investigated. MICP promoting fluids were injected into sand-filled columns and the resulting calcium conversion was measured. At the end of the injections, the MICP treated specimens were tested for cementation uniformity. The amount of precipitated CaCO 3 gradually decreased as the distance from the injection ports increases. The observed bio-cementation distribution could be attributed to the filtration of bacterial cells through the soil particles. The resulting effect of filtration on CaCO 3 distribution was observed to be more prominent for silty sands, presumably due to the presence of fine grains. Thermal conductivity measurements were assessed after each pulse during the MICP treatment using a TR-3 sensor. Under the saturated and untreated conditions, thermal conductivity increased with increasing fines content. In addition, MICP treatment can increase the thermal conductivity of saturated silty sands with the increasing number of treatment pulses. An increase of about 18% in thermal conductivity of the soil was achieved at an average CaCO 3 content of 10.7% presumably due to the formation of calcium carbonate bridges binding the soil grains together. The results presented herein suggests that MICP treatment can be a viable option to increase the thermal conductivity of soils in the range of fines content studied here (less than 15%). The findings of this research could be used to improve the efficiency of geothermal boreholes and other energy geo-structures using MICP by improving thermal conductivity of dry and partially saturated soil.Item Biomass distributions, activity, growth, and carbon utilization in heterotrophic bacterial communities(Montana State University - Bozeman, College of Agriculture, 1999) Ellis, B. D.Item Nitrate reduction by denitrifying bacteria within a porous medium(Montana State University - Bozeman, College of Engineering, 1998) Begaye-Ibbotson, Evangeline M.Acid processing of uranium ore resulted in aquifer contamination (nitrate, sulfate, and uranium) of the aquifer associated with the Navajo Sandstone formation at Tuba City, Arizona. The objectives of this study focused on the use of bioprocesses to remediate this aquifer contamination. The bench-scale objective of this study was to evaluate the ability of an indigenous microbial consortium to bioremediate nitrate contamination. The reduction of nitrate typically results in the production of nitrite, which under most conditions is further reduced to dinitrogen gas or ammonia. However, under some conditions inhibitory concentrations of nitrite may accumulate. Sandstone-packed columns fed with aquifer-relevant concentrations of nitrate were used to assess denitrification rates by indigenous bacteria. To enumerate denitrifying consortia used in the column experiments, most probable number (MPN) techniques were used. Sandstone-packed column influent and effluent data for nitrate, nitrite, carbon substrate and biomass concentrations were collected over time. These data were used to assess nitrate reduction rates within a sandstone column. This research demonstrates that with indigenous bacteria with stable conditions nitrate is reduced to dinitrogen forming only minimum levels of nitrite which should not inhibit sulfate-reducing bacteria (SRBs). The results of these studies indicate that bacterial denitrification has good potential as a remediation strategy for nitrate-contaminated groundwater to levels below the established regulatory limits of 44 mg/L. Field tests applications are planned for the Department of Energy UMTRA site in Tuba City, Arizona, using an extensive grid of injection and pumping wells.Item Systems analysis of engineered and natural microbial consortia(Montana State University - Bozeman, College of Engineering, 2013) Bernstein, Hans Christopher; Chairperson, Graduate Committee: Ross Carlson; Ross P. Carlson was a co-author of the article, 'Microbial consortia engineering for cellular factories: in vitro to in silico systems' in the journal 'Computational and structural biotechnology journal' which is contained within this thesis.; Ross P. Carlson was a co-author of the article, 'Design, construction and characterization methodologies for synthetic microbial consortia' in the book 'Methods in molecular biology, engineering multicellular system' which is contained within this thesis.; Steven D. Paulson and Ross P. Carlson were co-authors of the article, 'Synthetic Escherichia coli consortia engineered for syntrophy demonstrate enhanced biomass productivity' in the journal 'Journal of biotechnology' which is contained within this thesis.; Maureen Kessano, Karen Moll, Terence Smith, Robin Gerlach, Ross P. Carlson, Brent M. Peyton, Robert D. Gardner and Ronald C. Sims were co-authors of the article, 'Direct measurement and characterization of active photosynthesis zones inside biofuel producing and waste-water remediating algal biofilms' submitted to the journal 'Biotechnology and bioengineering' which is contained within this thesis.; Jacob P. Beam, Mark A. Kozubal, Ross P. Carlson and William P. Inskeep were co-authors of the article, 'In situ analysis of oxygen consumption and diffusive transport in high-temperature acidic iron-oxide microbial mats' in the journal 'Environmental Microbiology' which is contained within this thesis.; Alissa Bleem, Steven Davis and Ross P. Carlson were co-authors of the article, 'Chacterization of an artificial photoautotrophic-heterotrophic biofilm consortium composed of synechococcus PCC 7002 and Escherichia coli MG1655' which is contained within this thesis.Microorganisms are ubiquitous and typically exist within complex interacting communities or consortia. Microbial consortia are capable of cooperating in a coordinated fashion to extract mass and free energy from their environment. Chemical and biological engineers have long been keen to harness microbial processes for the development of technologies with applications ranging from energy capture to environmental remediation to human health. The pursuit of novel microbial biotechnologies has given rise to the relatively new discipline of microbial consortia engineering, which differs from and expands upon more traditional monoculture based practices. Many successful examples of applied and/or engineered microbial consortia mimic fundamental ecological strategies observed from nature, highlighting the importance for engineers to study natural biological phenomena. The overarching goal for this dissertation was to observe and quantitatively characterize interactions and physical phenomena occurring within select microbial consortial systems. The technical research presented here explores microbial consortia on three main fronts: (i) metabolically engineered heterotrophic systems, (ii) photoautotrophic-heterotrophic biofilm systems and (iii) naturally occurring thermo-acidophilic microbial mat systems. The metabolically engineered systems were designed to mimic a common ecological strategy involving syntrophic metabolite exchange via primary-productivity coupled with secondary consumption of potentially inhibitory byproducts (i.e., acetic acid). This system exhibited enhanced biomass productivity as compared to monoculture controls. The primary-productivity concept was also explored, in a more traditional sense, by characterizing production, consumption and exchanges of oxygen within photoautotrophic-heterotrophic biofilm systems. Tight spatial coupling of oxygenic-photosynthesis and aerobic-respiration was observed in both biofuel producing and waste-water remediating biofilm communities. The role of oxygen as an important terminal electron acceptor was also investigated in pristine Fe(III)-oxide microbial mats from geothermal springs located in Yellowstone National Park (USA). For these systems, oxygen availability defines ecological niche environments that spatially govern specific community member abundances and activities. Classical chemical engineering reaction and diffusion analysis was used to model concentration dependent oxygen consumption kinetics and establish that these mats are likely mass transfer limited. Both primary-productivity and microbially mediated oxygen reactions are interrelated, cross-cutting themes throughout this dissertation. The research described here is interdisciplinary chemical engineering that utilizes fundamental microbial ecology as a foundational platform.