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Traditional public health strategies for assessing human behavior, exposure, and activity are considered resource-exhaustive, time-consuming, and expensive, warranting a need for alternative methods to enhance data acquisition and subsequent interventions. This dissertation critically evaluated the use of wastewater-based epidemiology (WBE) as an inclusive and non-invasive tool for conducting near real-time population health assessments. A rigorous literature review was performed to gauge the current landscape of WBE to monitor for biomarkers indicative of diet, as well as exposure to estrogen-mimicking endocrine disrupting (EED) chemicals via route of ingestion. Wastewater-derived measurements of phytoestrogens from August 2017 through July 2019 (n = 156 samples) in a small sewer catchment revealed seasonal patterns, with highest average per capita consumption rates in January through March of each year (2018: 7.0 ± 2.0 mg d-1; 2019: 8.2 ± 2.3 mg d-1) and statistically significant differences (p = 0.01) between fall and winter (3.4 ± 1.2 vs. 6.1 ± 2.9 mg d-1; p ≤ 0.01) and spring and summer (5.6 ± 2.1 vs. 3.4 ± 1.5 mg d-1; p ≤ 0.01). Additional investigations, including a human gut microbial composition analysis of community wastewater, were performed to support a methodological framework for future implementation of WBE to assess population-level dietary behavior. In response to the COVID-19 global pandemic, a high-frequency, high-resolution sample collection approach with public data sharing was implemented throughout the City of Tempe, Arizona, and analyzed for SARS-CoV-2 (E gene) from April 2020 through March 2021 (n = 1,556 samples). Results indicate early warning capability during the first wave (June 2020) compared to newly reported clinical cases (8.5 ± 2.1 days), later transitioning to a slight lagging indicator in December/January 2020-21 (-2.0 ± 1.4 days). A viral hotspot from within a larger catchment area was detected, prompting targeted interventions to successfully mitigate community spread; reinforcing the importance of sample collection within the sewer infrastructure. I conclude that by working in tandem with traditional approaches, WBE can enlighten a comprehensive understanding of population health, with methods and strategies implemented in this work recommended for future expansion to produce timely, actionable data in support of public health.
ContributorsBowes, Devin Ashley (Author) / Halden, Rolf U (Thesis advisor) / Krajmalnik-Brown, Rosa (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Varsani, Arvind (Committee member) / Whisner, Corrie (Committee member) / Arizona State University (Publisher)
Created2022
Description
While most household surfactants are biodegradable in aerobic conditions, their presence in a microbiological treatment process can lead to the proliferation of antimicrobial-resistance genes (ARG) in bacteria, such as Pseudomonas aeruginosa. Surfactants can be cationic, anionic, or zwitterionic, and these different classes may have different effects on the proliferation of ARG. This study evaluated how the three classes of surfactants affected the microbial community’s structure and ARG in O2-based membrane biofilm reactors (O2-MBfRs) that provided at least 98% surfactant removal. Cationic cetrimonium bromide (CTAB) had by far the strongest impact with highest ARG abundance in the biofilm. In particular, Pseudomonas and Stenotrophomonas, the two main genera in the biofilm treating CTAB, were highly correlated to the abundance of ARG for efflux pumps and antibiotic inactivation. CTAB also promoted potential of horizontal gene transfer (HGT) of ARG. Combining results from the metabolome and metagenome identified four possible pathways for CTAB biodegradation. Of special important is a new pathway: β-carbon oxidation of CTAB to produce betaine. An insufficient nitrogen source could lead to irreversible ARB and ARG enrichment in the MBfR biofilm. Finally, a two-stage O2-MBfR successfully removed a high concentration (730 mg/L) of CTAB: Partial CTAB removal in the Lead reactor relieved inhibition in the Lag reactor. Metagenomic analysis also revealed that the Lag reactor was enriched in genes for CTAB and metabolite oxygenation.
ContributorsZheng, Chenwei (Author) / Rittmann, Bruce (Thesis advisor) / Delgado, Anca (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Lai, Yen-Jung (Committee member) / Arizona State University (Publisher)
Created2023
Description
As the utilization of tyrosine is needed by both eukaryotes and prokaryotes, this versatile amino acid contributes towards a variety of operations including protein synthesis, pigment production, and host or habitat impacting metabolite creation. While there are numerous pathways which involve the degradation of tyrosine to create different products, the one that is central in this thesis is a pathway with homogentisate as an intermediate. This pathway brings an interest due to its association with metabolic disorders like Tyrosinemia (I, II, or III), and its impact within an agricultural environment. In other words, for humans and plant microbiomes to maintain their optimal metabolic homeostasis, tyrosine is required to participate in numerous demands. This necessity can ultimately create competition between organisms present in microbial communities, as there are a multitude of species that can metabolize tyrosine for the creation of diverse products. In this work, a primary objective is to characterize the breakdown of tyrosine within a competitive environment where there are multiple available pathways. There are many factors that could influence the catabolism of tyrosine like catalytic efficiency of enzymes, availability of breakdown routes, and pathway regulations. Here, the start will be creating a proof of concept developed by studying the competition for tyrosine utilization by environmental microbial enzymes; 4-hydroxyphenylpyruvate dioxygenase from Streptomyces avermitilis, 4-hydroxymandelate synthase from Amycolatopsis orientalis, and tyrosine ammonia lyase from Flavobacterium johnsoniae. Through phenotypic assays and by quantifying secreted metabolites, rerouting of this pathway is observed. This insight towards the ability of diverting the homogentisate pathway was then utilized for the analysis of contest between human enzyme, 4-hydroxyphenylpyruvate dioxygenase, and gut microbial enzyme, tyrosine ammonia lyase from Bacteroides ovatus. Within both aims it is seen that due to successful diversion of the pathway, there is a reduction in tyrosine with the formation of more favorable products. The strategy of redirecting this tyrosine catabolism pathway will provide baseline knowledge for future efforts to contribute towards alternative methods of intervention to alleviate the burdens from tyrosine metabolic dysfunction and disorders.
ContributorsMitchem, Madison (Author) / Shah, Dhara D (Thesis advisor) / Misra, Rajeev (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2024
Description
Widespread use of chlorinated solvents for commercial and industrial purposes makes co-occurring contamination by 1,1,1-trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) a serious problem for groundwater. TCE and TCA often are treated by reductive dechlorination, while 1,4-D resists reductive treatment. Aerobic bacteria are able to oxidize 1,4-D, but the biological oxidation of 1,4-D could be inhibited TCA, TCE, and their reductive transformation products. To overcome the challenges from co-occurring contamination, I propose a two-stage synergistic system. First, anaerobic reduction of the chlorinated hydrocarbons takes place in a H2-based hollow-fiber “X-film” (biofilm or catalyst-coated film) reactor (MXfR), where “X-film” can be a “bio-film” (MBfR) or an abiotic “palladium-film” (MPfR). Then, aerobic removal of 1,4-D and other organic compounds takes place in an O2-based MBfR. For the reductive part, I tested reductive bio-dechlorination of TCA and TCE simultaneously in an MBfR. I found that the community of anaerobic bacteria can rapidly reduce TCE to cis-dichloroethene (cis-DCE), but further reductions of cis-DCE to vinyl chloride (VC) and VC to ethene were inhibited by TCA. Also, it took months to grow a strong biofilm that could reduce TCA and TCE. Another problem with reductive dechlorination in the MBfR is that mono-chloroethane (MCA) was not reduced to ethane. In contrast, a film of palladium nano-particles (PdNPs), i.e., an MPfR, could the simultaneous reductions of TCA and TCE to mainly ethane, with only small amounts of intermediates: 1,1-dichloroethane (DCA) (~3% of total influent TCA and TCE) and MCA (~1%) in continuous operation. For aerobic oxidation, I enriched an ethanotrophic culture that could oxidize 1,4-D with ethane as the primary electron donor. An O2-based MBfR, inoculated with the enriched ethanotrophic culture, achieved over 99% 1,4-D removal with ethane as the primary electron donor in continuous operation. Finally, I evaluated two-stage treatment with a H2-based MPfR followed by an O2-MBfR. The two-stage system gave complete removal of TCA, TCE, and 1,4-D in continuous operation.
ContributorsLuo, Yihao (Author) / Rittmann, Bruce E. (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Zhou, Chen (Committee member) / Arizona State University (Publisher)
Created2018
Description
Petroleum contamination is ubiquitous during extraction, transportation, refining, and storage. Contamination damages the soil’s ecosystem function, reduces its aesthetics, and poses a potential threat to human beings. The overall goals of this dissertation are to advance understanding of the mechanisms behind ozonation of petroleum-contaminated soil and to configure an effective integrated bioremediation + ozonation remedial strategy to remove the overall organic carbon. Using a soil column, I conducted batch ozonation experiments for different soils and at different moisture levels. I measured multiple parameters: e.g., total petroleum hydrocarbons (TPH) and dissolved organic carbon (DOC), to build a full understanding of the data that led to the solid conclusions. I first demonstrated the feasibility of using ozone to attack heavy petroleum hydrocarbons in soil settings. I identified the physical and chemical hurdles (e.g., moisture, mass transfer, pH) needed to be overcome to make the integration of chemical oxidation and biodegradation more efficient and defines the mechanisms behind the experimental observations. Next, I completed a total carbon balance, which revealed that multiple components, including soil organic matter (SOM) and non-TPH petroleum, competed for ozone, although TPH was relatively more reactive. Further experiments showed that poor soil mixing and high soil-moisture content hindered mass transfer of ozone to react with the TPH. Finally, I pursued the theme of optimizing the integration of ozonation and biodegradation through a multi-stage strategy. I conducted multi-stages of ozonation and bioremediation for two benchmark soils with distinctly different oils to test if and how much ozonation enhanced biodegradation and vice versa. With pH and moisture optimized for each step, pre-ozonation versus post-ozonation was assessed for TPH removal and mineralization. Multi-cycle treatment was able to achieve the TPH regulatory standard when biodegradation alone could not. Ozonation did not directly enhance the biodegradation rate of TPH; instead, ozone converted TPH into DOC that was biodegraded and mineralized. The major take-home lesson from my studies is that multi-stage ozonation + biodegradation is a useful remediation tool for petroleum contamination in soil.
ContributorsChen, Tengfei (Author) / Rittmann, Bruce E. (Thesis advisor) / Westerhoff, Paul (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Delgado, Anca G (Committee member) / Arizona State University (Publisher)
Created2018
Description
This dissertation critically evaluated methodologies and devices for assessing and protecting the health of human populations, with particular emphasis on groundwater remediation and the use of wastewater-based epidemiology (WBE) to inform population health. A meta-analysis and assessment of laboratory-scale treatability studies for removing chlorinated solvents from groundwater found that sediment microcosms operated as continuous-flow columns are preferable to batch bottles when seeking to emulate with high fidelity the complex conditions prevailing in the subsurface in contaminated aquifers (Chapter 2). Compared to monitoring at the field-scale, use of column microcosms also showed (i) improved chemical speciation, and (ii) qualitative predictability of field parameters (Chapter 3). Monitoring of glucocorticoid hormones in wastewater of a university campus showed (i) elevated stress levels particularly at the start of the semester, (ii) on weekdays relative to weekend days (p = 0.05) (161 ± 42 μg d-1 per person, 122 ± 54 μg d-1 per person; p ≤ 0.05), and (iii) a positive association between levels of stress hormones and nicotine (rs: 0.49) and caffeine (0.63) consumption in this student population (Chapter 4). Also, (i) alcohol consumption determined by WBE was in line with literature estimates for this young sub-population (11.3 ± 7.5 g d-1 per person vs. 10.1 ± 0.8 g d-1 per person), whereas caffeine and nicotine uses were below (114 ± 49 g d-1 per person, 178 ± 19 g d-1 per person; 627 ± 219 g d-1 per person, 927 ± 243 g d-1 per person). The introduction of a novel continuous in situ sampler to WBE brought noted benefits relative to traditional time-integrated sampling, including (i) a higher sample coverage (93% vs. 3%), (ii) an ability to captured short-term analyte pulses (e.g., heroin, fentanyl, norbuprenorphine, and methadone), and (iii) an overall higher mass capture for drugs of abuse like morphine, fentanyl, methamphetamine, amphetamine, and the opioid antagonist metabolite norbuprenorphine (p ≤ 0.01). Methods and devices developed in this work are poised to find applications in the remediation sector and in human health assessments.
ContributorsDriver, Erin Michelle (Author) / Halden, Rolf (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Kavazanjian, Edward (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2018
Description
The objective of this study was to evaluate possible bioremediation strategy for aerobic aquifers by combining ZVI chemical reduction and microbial reductive dechlorination for TCE and ClO4-. To achieve this objective, continuous flow-through soil columns were used to test the hypothesis that bioaugmentation with dechlorinating enrichment cultures downstream of the ZVI injection can lead to complete reduction of TCE and ClO4- in aerobic aquifers. We obtained soil and groundwater from a Superfund site in Arizona. The experiments consisted of 205 cm3 columns packed with soil and ZVI, which fed 1025 cm3 columns packed with soil, biostimulated with fermentable substrates and bioaugmented. Aerobic groundwater was pumped through the ZVI columns. The ZVI reduced the oxidation-reduction potential (ORP) of groundwater from +150 mV to -190 mV. The reduced groundwater and biostimulation with fermentable substrates created anaerobic conditions in the bioaugmentation columns favorable for anaerobic microbial activity. Perchlorate (ClO4-) reduction to non-detectable levels occurred after biostimulation. Reduction of TCE to cis-dichloroethene, vinyl chloride and ethene was observed only after bioaugmentation. Within ~120 days of continuous columns operation, ethene was produced in the bioaugmentation columns this dechlorination activity was sustained until the end of experiments. The groundwater from the Superfund site had high concentration of sulfate (~1000 mg/L). Substantial sulfate reduction occurred in the bioaugmentation columns. Complete microbial reduction of TCE and perchlorate is usually challenging in the presence of high sulfate concentration; however, the strategy tested in this study suggests that a bioremediation scheme for simultaneous reduction of TCE and perchlorate in aerobic aquifers containing high sulfate concentration is feasible.
ContributorsRao, Shefali (Author) / Krajmalnik-Brown, Rosa (Thesis advisor) / Delgado, Anca G. (Thesis advisor) / LaPat-Polasko, Laurie (Committee member) / Arizona State University (Publisher)
Created2019
Description
Microbial electrochemical cells (MXCs) offer an alternative to methane production in anaerobic water treatment and the recapture of energy in waste waters. MXCs use anode respiring bacteria (ARB) to oxidize organic compounds and generate electrical current. In both anaerobic digestion and MXCs, an anaerobic food web connects the metabolisms of different microorganisms, using hydrolysis, fermentation and either methanogenesis or anode respiration to break down organic compounds, convert them to acetate and hydrogen, and then convert those intermediates into either methane or current. In this dissertation, understanding and managing the interactions among fermenters, methanogens, and ARB were critical to making developments in MXCs. Deep sequencing technologies were used in order to identify key community members, understand their role in the community, and identify selective pressures that drove the structure of microbial communities. This work goes from developing ARB communities by finding and using the best partners to managing ARB communities with undesirable partners. First, the foundation of MXCs, namely the ARB they rely on, was expanded by identifying novel ARB, the genus Geoalkalibacter, and demonstrating the presence of ARB in 7 out of 13 different environmental samples. Second, a new microbial community which converted butyrate to electricity at ~70% Coulombic efficiency was assembled and demonstrated that mixed communities can be used to assemble efficient ARB communities. Third, varying the concentrations of sugars and ethanol fed to methanogenic communities showed how increasing ED concentration drove decreases in methane production and increases in both fatty acids and the propionate producing genera Bacteroides and Clostridium. Finally, methanogenic batch cultures, fed glucose and sucrose, and exposed to 0.15 – 6 g N-NH4+ L-1 showed that increased NH4+ inhibited methane production, drove fatty acid and lactate production, and enriched Lactobacillales (up to 40% abundance) above 4 g N-NH4+ L-1. Further, 4 g N-NH4+ L-1 improved Coulombic efficiencies in MXCs fed with glucose and sucrose, and showed that MXC communities, especially the biofilm, are more resilient to high NH4+ than comparable methanogenic communities. These developments offer new opportunities for MXC applications, guidance for efficient operation of MXCs, and insights into fermentative microbial communities.
ContributorsMiceli, Joseph (Author) / Torres, César I (Thesis advisor) / Krajmalnik-Brown, Rosa (Thesis advisor) / Rittmann, Bruce (Committee member) / Arizona State University (Publisher)
Created2015
Description
Photosynthesis converts sunlight to biomass at a global scale. Among the photosynthetic organisms, cyanobacteria provide an excellent model to study how photosynthesis can become a practical platform of large-scale biotechnology. One novel approach involves metabolically engineering the cyanobacterium Synechocystis sp. PCC 6803 to excrete laurate, which is harvested directly.
This work begins by defining a working window of light intensity (LI). Wild-type and laurate-excreting Synechocystis required an LI of at least 5 µE/m2-s to sustain themselves, but are photo-inhibited by LI of 346 to 598 µE/m2-s.
Fixing electrons into valuable organic products, e.g., biomass and excreted laurate, is critical to success. Wild-type Synechocystis channeled 75% to 84% of its fixed electrons to biomass; laurate-excreting Synechocystis fixed 64 to 69% as biomass and 6.6% to 10% as laurate. This means that 16 to 30% of the electrons were diverted to non-valuable soluble products, and the trend was accentuated with higher LI.
How the Ci concentration depended on the pH and the nitrogen source was quantified by the proton condition and experimentally validated. Nitrate increased, ammonium decreased, but ammonium nitrate stabilized alkalinity and Ci. This finding provides a mechanistically sound tool to manage Ci and pH independently.
Independent evaluation pH and Ci on the growth kinetics of Synechocystis showed that pH 8.5 supported the fastest maximum specific growth rate (µmax): 2.4/day and 1.7/day, respectively, for the wild type and modified strains with LI of 202 µE/m2-s. Half-maximum-rate concentrations (KCi) were less than 0.1 mM, meaning that Synechocystis should attain its µmax with a modest Ci concentration (≥1.0 mM).
Biomass grown with day-night cycles had a night endogenous decay rate of 0.05-1.0/day, with decay being faster with higher LI and the beginning of dark periods. Supplying light at a fraction of daylight reduced dark decay rate and improved overall biomass productivity.
This dissertation systematically evaluates and synthesizes fundamental growth factors of cyanobacteria: light, inorganic carbon (Ci), and pH. LI remains the most critical growth condition to promote biomass productivity and desired forms of biomass, while Ci and pH now can be managed to support optimal productivity.
This work begins by defining a working window of light intensity (LI). Wild-type and laurate-excreting Synechocystis required an LI of at least 5 µE/m2-s to sustain themselves, but are photo-inhibited by LI of 346 to 598 µE/m2-s.
Fixing electrons into valuable organic products, e.g., biomass and excreted laurate, is critical to success. Wild-type Synechocystis channeled 75% to 84% of its fixed electrons to biomass; laurate-excreting Synechocystis fixed 64 to 69% as biomass and 6.6% to 10% as laurate. This means that 16 to 30% of the electrons were diverted to non-valuable soluble products, and the trend was accentuated with higher LI.
How the Ci concentration depended on the pH and the nitrogen source was quantified by the proton condition and experimentally validated. Nitrate increased, ammonium decreased, but ammonium nitrate stabilized alkalinity and Ci. This finding provides a mechanistically sound tool to manage Ci and pH independently.
Independent evaluation pH and Ci on the growth kinetics of Synechocystis showed that pH 8.5 supported the fastest maximum specific growth rate (µmax): 2.4/day and 1.7/day, respectively, for the wild type and modified strains with LI of 202 µE/m2-s. Half-maximum-rate concentrations (KCi) were less than 0.1 mM, meaning that Synechocystis should attain its µmax with a modest Ci concentration (≥1.0 mM).
Biomass grown with day-night cycles had a night endogenous decay rate of 0.05-1.0/day, with decay being faster with higher LI and the beginning of dark periods. Supplying light at a fraction of daylight reduced dark decay rate and improved overall biomass productivity.
This dissertation systematically evaluates and synthesizes fundamental growth factors of cyanobacteria: light, inorganic carbon (Ci), and pH. LI remains the most critical growth condition to promote biomass productivity and desired forms of biomass, while Ci and pH now can be managed to support optimal productivity.
ContributorsNguyen, Binh Thanh (Author) / Rittmann, Bruce E. (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2015
Description
Bioremediation of trichloroethene (TCE) using Dehalococcoides mccartyi-containing microbial cultures is a recognized and successful remediation technology. Our work with an upflow anaerobic sludge blanket (UASB) reactor has shown that high-performance, fast-rate dechlorination of TCE can be achieved by promoting bioflocculation of Dehalococcoides mccartyi-containing cultures. The bioreactor achieved high maximum conversion rates of 1.63 ± 0.012 mmol Cl- Lculture-1 h-1 at an HRT of 3.6 hours and >97% dechlorination of TCE to ethene while continuously fed 2 mM TCE. The UASB generated bioflocs from a microbially heterogeneous dechlorinating culture and produced Dehalococcoides mccartyi densities of 1.73x10-13 cells Lculture-1 indicating that bioflocculation of Dehalococcoides mccartyi-containing cultures can lead to high density inocula and high-performance, fast-rate bioaugmentation culture for in situ treatment. The successful operation of our pilot scale bioreactor led to the assessment of the technology as an onsite ex-situ treatment system. The bioreactor was then fed TCE-contaminated groundwater from the Motorola Inc. 52nd Street Plant Superfund site in Phoenix, AZ augmented with the lactate and methanol. The bioreactor maintained >99% dechlorination of TCE to ethene during continuous operation at an HRT of 3.2 hours. Microbial community analysis under both experimental conditions reveals shifts in the community structure although maintaining high rate dechlorination. High density dechlorinating cultures containing bioflocs can provide new ways to 1) produce dense bioaugmentation cultures, 2) perform ex-situ bioremediation of TCE, and 3) increase our understanding of Dehalococcoides mccartyi critical microbial interactions that can be exploited at contaminated sites in order to improve long-term bioremediation schemes.
ContributorsFajardo-Williams, Devyn (Author) / Krajmalnik-Brown, Rosa (Thesis advisor) / Torres, César I (Committee member) / Popat, Sudeep C (Committee member) / Arizona State University (Publisher)
Created2015