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Lactate and methanol have been the most commonly used electron donors in the Krajmalnik-Brown laboratory for efficient microbial dechlorination of trichloroethene (TCE). Our goal was to assess the technical and economic feasibility of molasses and ethanol, two alternative electron donors by evaluating their costs and ability support complete TCE dechlorination to ethene. First, ethanol and molasses, with and without methanol, were evaluated for their abilities to support complete dechlorination in batch serum bottles. Molasses, the cheapest alternative, supported a similar dechlorination performance to lactate in batch experiments, so we then used it in an upflow anaerobic bioreactor (UABR) to test its ability to support rapid dechlorination in this continuous system. Molasses supported 88% TCE conversion to ethene at a hydraulic retention time (HRT) of 13 hours after 80 days of operation in continuous mode. Compared to the UABR operated previously using lactate and methanol, molasses led to a reduction of TCE conversion to ethene, and a possible increase in time required to produce culture. Additionally, when molasses was used as the electron donor, we encountered new difficulties in the operation of the UABR, such as drastic pH changes. Therefore, I conclude that the savings from using molasses is outweighed by the costs associated with the reduction in dechlorination performance and increase in reactor maintenance. I recommend that lactate and methanol continue to be used as the electron donors in the Krajmalnik- Brown dechlorination lab to support fast-rate and cost-effective production of dechlorinating culture in an UABR. Because molasses supported fast rates of dechlorination in the batch experiment, however, it is potentially a better option than lactate and methanol for batch production of culture or for biostimulation, where the aquifer resembles a batch system. I recommend that further studies be done to reach a general conclusion about the feasibility of molasses as an electron donor for other enhanced bioremediation projects.
ContributorsBondank, Emily Nicole (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Delgado, Anca (Committee member) / Torres, Cesar (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2014-12
Description
A meta-analysis was conducted to compare the total amount of ionic liquid (IL) literature (n = 39,036) to the body of publications dealing with IL toxicity (n = 213), with the goal of establishing the state of knowledge and existing information gaps. Publications on IL toxicity were collected from the SciFinder database and sorted by cation and model organism studied. Studies focusing on pharmacokinetics and drug development were excluded, as were structure-activity relationship methods of data collection. Total publishing activity was used as a measure to gauge research and industrial usage of ILs as well as the knowledge base of toxicology. Five of the most commonly studied IL cations were identified and used to establish a relationship between toxicity data and potential of commercial use: imidazolium, ammonium, phosphonium, pyridinium, and pyrrolidinium. Toxicology publications for all IL cations represented 1.2% ± 0.62% of the total publishing activity; compared with other industrial chemicals, these numbers indicate that there is still a paucity of studies on the adverse effects of this class of chemicals. In vitro models and marine bacteria were the most frequently studied biological systems, contributing 18% and 15%, respectively, to the total body of IL toxicity studies. Whole animal studies (n = 87) comprised 41% of IL toxicity studies, with a subset of in vivo mammalian models consisting of 8%. Human toxicology data were found to be limited to in vitro analyses, indicating substantial knowledge gaps. Risks from long-term and chronic low-level exposure to ILs have not been established yet for any model organisms, reemphasizing the need for filling crucial knowledge gaps concerning human health effects and the environmental safety of ILs. Adding to the existing knowledge of the molecular toxicity characteristics of ILs can help inform the design of greener, less toxic and more benign IL technologies.
ContributorsHeckenbach, Mary (Co-author) / Halden, Rolf (Co-author, Thesis director) / Jehn, Megan (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
This is a study of the adaptive behaviors of individuals with Autism Spectrum Disorder using the Vineland II Adaptive Behavioral Scale (VABS-II). This scale was used to determine the overall functioning level of individuals with Autism Spectrum Disorder at the beginning, and will be used at the end, of a year-long study beginning at Arizona State University. This larger study is determining what the effects are, if any, of a combination of nutritional and dietary treatments in individuals with Autism Spectrum Disorder. However, this paper only examines the VABS-II results of forty-three participants in the study, as well as their hand-grip strength. It was found that individuals with Autism Spectrum Disorder are substantially delayed in all four domains (communication, daily living skills, social skills, and motor skills) of adaptive behaviors measured by the VABS-II, particularly in communication. This study will be completed in May 2013, when it will be determined what the effects of these treatments are, if any.
ContributorsAdams, Rebecca (Author) / Ingram-Waters, Mary (Thesis director) / Krajmalnik-Brown, Rosa (Committee member) / Pollard, Elena (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
In the United States, the prevalence of pediatric obesity has increased to 17% in the general population and even more so in the Hispanic pediatric population to 22.4%. These children are at a higher risk for associated comorbidities, including cardiovascular disease and insulin resistance. The purpose of the following study is to determine the effectiveness of the Nutrition and Health Awareness curriculum at reducing childhood obesity by evaluating alterations in the gut microbial composition, diet, and overall health of the students throughout the five-week program. Nutrition and Health Awareness (NHA) is a student organization that strives to reduce the prevalence of obesity, diabetes, and cardiovascular diseases, specifically in children, by providing active nutrition education services through peer mentoring in elementary schools and community programs. This study went through ASU's Institutional Review Board process and all forms were translated into Spanish. The control group maintained their normal routines and the experimental group received the 5 week NHA program and then continued with their normal routines. Anthropometric measures (Body Mass Index, waist-to-hip ratio, and blood pressure), diet measures (Hispanic food frequency questionnaire), fecal swabs, and content surveys were collected on weeks 0, 5, and 8. Contrary to expected, alpha diversity, kilocalorie intake, and macronutrient intake decreased as the study progressed for both the control and experimental groups. Anthropometric measurements were relatively stable. Though not statistically significant, the greatest difference in time points is between weeks 1 and 8. This decrease in alpha diversity and kilocalorie intake could be due to a change in environment since the children started school on week 8. Future implications of this study are that parental involvement is necessary for an effective, sustainable change in these children. More research in different settings is necessary to determine NHA's effectiveness
ContributorsPatel, Kapila Cristina (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Whisner, Corrie (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Microorganisms can produce metabolites in the gut including short chain fatty acids, vitamins, and amino acids. Certain metabolites produced in the gut can affect the brain through changes in neurotransmitter concentrations. Serotonin, a neurotransmitter, is associated with mood, appetite, and sleep. Up to 90% of serotonin synthesis is located in the gut, by human enterochromaffin cells. Bacteria known to biosynthesize tryptophan, precursor to serotonin, include Escherichia coli, Enterococcus and Streptococcus. Tryptophan is synthesized by bacteria with the enzyme tryptophan synthase and requires Vitamin B6 (Pyridoxal). We hypothesize that gut isolates from surgical weight loss patients can enhance tryptophan production, which relies on vitamin B6 availability. Our goal was to isolate bacteria in order to test for tryptophan production and to determine how Vitamin B6 concentrations could affect tryptophan production. We isolated gut bacteria was from successful surgical weight loss patient with selective pressures for Enterobacter isolates and Enterococcus isolates. We tested the isolates were tested to determine if they could biosynthesize tryptophan in-vitro. Bacterial cultures were enriched with yeast and enriched with serine and indole, substrates necessary for tryptophan biosynthesis. We analyzed the supernatant samples for tryptophan production using GC-FID. Bacterial isolates most closely related to E. coli and Klebsiella based on 16S rRNA gene sequences, produced tryptophan in vitro. While under serine & indole media conditions, R1, the isolate most similar to Klebsiella produced more tryptophan than R14, the isolate most similar to E. coli. We tested the R1 isolate with a gradient of vitamin B6 concentrations from 0.02 µg/mL to 0.2 µg/mL to determine its effect on tryptophan production. When less than 0.05 µg/mL of Vitamin B6 was added, tryptophan production at 6 hours was higher than tryptophan production with Vitamin B6 concentrations at 0.05 µg/mL and above. The production and consumption of tryptophan by Klebsiella under 0 µg/mL and 0.02 µg/mL concentrations of Vitamin B6 occurred at a faster rate when compared to concentrations 0.05 µg/mL or higher of Vitamin B6.
ContributorsYee, Emily L. (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Ilhan, Zehra (Committee member) / W. P. Carey School of Business (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Hydrogen is a key indicator of microbial activity in soils/sediments and groundwater because of its role as an electron donor for reducing sulfate and nitrate and carrying out other metabolic processes. The goal of this study was to quantitatively measure the total biological hydrogen demand (TBHD) of soils and sediments in anaerobic environments. We define the total biological hydrogen demand as the sum of all electron acceptors that can be used by hydrogen-oxidizing microorganisms. Three sets of anaerobic microcosms were set up with different soils/sediments, named Carolina, Garden, and ASM. The microcosms included 25g of soil/sediment and 75 mL of anaerobic medium. 10 mL of hydrogen were pulse-fed for 100 days. Hydrogen consumption and methane production were tracked using gas chromatography. Chemical analysis of each soil was performed at the beginning of the experiment to determine the concentration of electron acceptors in the soils/sediments, including nitrate, sulfate, iron and bicarbonate. An analysis of the microbial community was done at t = 0 and at the end of the 100 days to examine changes in the microbial community due to the metabolic processes occurring as hydrogen was consumed. Carolina consumed 9810 43 mol of hydrogen and produced 19,572 2075 mol of methane. Garden consumed 4006 33 mol of hydrogen and produced 7,239 543 mol of methane. Lastly, ASM consumed 1557 84 mol of hydrogen and produced 1,325 715 mol of methane. I conclude that the concentration of bicarbonate initially present in the soil had the most influence over the hydrogen demand and microbial community enrichment. To improve this research, I recommend that future studies include a chemical analysis of final soil geochemistry conditions, as this will provide with a better idea of what pathway the hydrogen is taking in each soil.
ContributorsLuna Aguero, Marisol (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Delgado, Anca (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
With a rapidly decreasing amount of resources for construction, wood and bamboo have been suggested as renewable materials for increased use in the future to attain sustainability. Through a literature review, bamboo and wood growth, manufacturing and structural attributes were compared and then scored in a weighted matrix to determine the option that shows the higher rate of sustainability. In regards to the growth phase, which includes water usage, land usage, growth time, bamboo and wood showed similar characteristics overall, with wood scoring 1.11% higher than bamboo. Manufacturing, which captures the extraction and milling processes, is experiencing use of wood at levels four times those of bamboo, as bamboo production has not reached the efficiency of wood within the United States. Structural use proved to display bamboo’s power, as it scored 30% higher than wood. Overall, bamboo received a score 15% greater than that of wood, identifying this fast growing plant as the comparatively more sustainable construction material.
ContributorsThies, Jett Martin (Author) / Ward, Kristen (Thesis director) / Halden, Rolf (Committee member) / Industrial, Systems & Operations Engineering Prgm (Contributor) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The effect of an anaerobic reductive environment produced by the oxidation of zero valent iron (ZVI) on the microbial reductive dechlorination of trichloroethylene and its applicability to in-situ bioremediation processes was investigated using microcosms and soil column studies. I learned that microbial dechlorination requires a highly reductive environment, as represented by negative values for oxidation-reduction potential (ORP), which can be maintained through the addition of reducing agents such as ZVI, or to a lesser extent, the fermentation of added substrates such as lactate. Microcosm conditions represented distance from an in-situ treatment injection well and contained different types of iron species and dechlorinating bioaugmentation cultures. Diminishing efficacy of microbial reductive dechlorination along a gradient away from the injection zone was observed, characterized by increasing ORP and decreasing pH. Results also suggested that the use of particular biostimulation substrates is key to prioritizing the dechlorination reaction against competing microbial and abiotic processes by supplying electrons needed for microbial dechlorination.
ContributorsMouti, Aatikah (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Delgado, Anca (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The gastrointestinal (GI) tract is home to a complex and diverse microbial ecosystem that contributes to health or disease in many aspects. While bacterial species are the majority in the GI tract, their cohabitants, fungal species, should not be forgotten. Children with autism spectrum disorder (ASD) often suffer from GI disorders and associated symptoms, implying a role the bacterial and fungal gut microbiota play in maintaining human health. The irregularities in GI symptoms can negatively affect the overall quality of life or even worsen behavioral symptoms the children present. Even with the increase in the availability of next-generation sequencing technologies, the composition and diversities of fungal microbiotas are understudied, especially in the context of ASD. We therefore aimed to investigate the gut mycobiota of 36 neurotypical children and 38 children with ASD. We obtained stool samples from all participants, as well as autism severity and GI symptom scores to help us understand the effect the mycobiome has on these symptoms. By targeting the fungal internal transcribed spacer (ITS) and bacterial 16S rRNA V4 regions, we obtained fungal and bacterial amplicon sequences, from which we investigated the diversities, composition, and potential link between two different ecological clades. From fungal amplicon sequencing results, we observed a significant decrease in the observed fungal OTUs in children with ASD, implying a lack of potentially beneficial fungi in ASD subjects. We performed Bray-Curtis principal coordinates analysis and observed significant differences in fungal microbiota composition between the two groups. Taxonomic analysis showed higher relative abundances of Candida , Pichia, Penicillium , and Exophiala in ASD subjects, yet due to a large dispersion of data, the differences were not statistically significant. Interestingly, we observed a bimodal distribution of Candida abundances within children with ASD. Candida's relative abundance was not significantly correlated with GI scores, but children with high Candida relative abundances presented significantly higher Autism Treatment Evaluation Checklist (ATEC) scores, suggesting a role of Candida on ASD behavioral symptoms. Regarding the bacterial gut microbiota, we found marginally lower observed OTUs and significantly lower relative abundance of Prevotella in the ASD group, which was consistent with previous studies. Taken together, we demonstrated that autism is closely linked with a distinct gut mycobiota, characterized by a loss of fungal and bacterial diversity and an altered fungal and bacterial composition.
ContributorsPatel, Jigar (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Kang, Dae Wook (Committee member) / Adams, James (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Trichloroethene (TCE) and hexavalent chromium [Cr(VI)] are toxic and carcinogenic contaminants found in drinking water resources across the United States. A series of Bench-scale treatability studies were conducted to evaluate the effectiveness of a consortium of facultative and strictly anaerobic bacteria, KB-1®, to remove TCE and Cr(VI) from a contaminated aquifer in San Diego. These series of treatability studies were also performed to prepare data and mature packed sediment columns for the deployment of the In Situ Microcosm Array (ISMA), a diagnostic device for determining optimal treatments for a contaminated aquifer, at this particular site. First, a control panel for the ISMA’s Injection Module (IM) was created in order to deliver nutrients to the columns. Then, a column treatability study was performed in order to produce columns with an established KB-1® consortium, so that all TCE in the column influent was converted to ethene by the time it had exited the column. Finally, a batch bottle treatability study was performed to determine KB-1®’s effectiveness at remediating both TCE and Cr(VI) from the San Diego ground-water samples. The results from the column study found that KB-1® was able to reduce TCE in mineral media. However, in the presence of site ground-water for the batch bottle study, KB-1® was only able to reduce Cr(VI) and no TCE dechlorination was observed. This result suggests that the dechlorinating culture cannot survive prolonged exposure to Cr(VI). Therefore, future work may involve repeating the batch bottle study with Cr(VI) removed from the groundwater prior to inoculation to determine if KB-1® is then able to dechlorinate TCE.
ContributorsDuong, Benjamin Taylor (Author) / Halden, Rolf (Thesis director) / Torres, Cesar (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Barrett, The Honors College (Contributor) / School of Dance (Contributor) / Chemical Engineering Program (Contributor)
Created2013-05