http://hdl.handle.net/1813/110 2013-05-11T23:36:35Z http://hdl.handle.net/1813/33215 Title: Upgrading dilute ethanol from syngas fermentation to n-caproate with reactor microbiomes Authors: Vasudevan, Divya Abstract: Fermentation of synthesis gas (syngas, which is a gas mixture including CO, H2, and CO2) from a renewable biomass source is gaining momentum. However, energy-intensive distillation of ethanol at dilute concentrations of 2-4% (w/w), which are anticipated for syngas fermentation with carboxydotrophic bacteria, is one impediment towards widespread adaptation. n-Caproic acid is a carboxylic acid with a chain length of six carbon atoms, and can be extracted more easily compared to ethanol. This because of its hydrophilic nature and its charge as n-caproate beyond a pKa of 4.88 while ethanol is completely miscible due to its short 2-carbon chain and hydrogen-bonding interactions. n-Caproic acid can be produced from ethanol in an anaerobic open culture (reactor microbiome) by chain elongation via the reversed β oxidation pathway. Here, we show a proof-of-concept to utilize diluted ethanol and acetic acid in real syngas fermentation effluent as the sole substrate for chain elongation into the product n-caproic acid. This concept, therefore, integrates the syngas platform and the carboxylate platform within a biorefinery. We observed with a bioreactor study that lowering the pH to slightly acidic conditions was necessary to shift the metabolic flux from production of methane to production of n-caproic acid. The highest concentration of n-caproic acid of ~ 1 g L-1 was produced at pH 5.44. 2013-05-08T00:00:00Z http://hdl.handle.net/1813/33209 Title: Energy requirement for continuous ethanol extraction via pervaporation and/or distillation at low concentrations Authors: Williams, Matthew Abstract: Syngas fermentation, or synthesis gas fermentation, is a microbial process that uses hydrogen, carbon dioxide, and carbon monoxide to produce fuel. The effluent in this process contains low concentration ethanol, which often ranges from 2 to 6 wt% ethanol. To make this ethanol usable, it must be concentrated to >95 wt% to be considered fuel grade ethanol. Most commonly, distillation is used to produce fuel grade ethanol, however this requires too much energy for low concentration ethanol feed streams. Therefore, there exists a need for an energy efficient process for converting low concentration ethanol feed streams to fuel grade ethanol. A model was made for a system that produces an ethanol-water effluent from a syngas fermenter that uses distillation alone to produce 95 wt% ethanol in the distillate. Then, a model was made for a system where the syngas fermentation effluent is first concentrated via a pervaporation module and then distilled. The flow rates in both models was calculated to find the amount of ethanol recovered in grams per hour. Then, the amount of energy required per hour was calculated for both models and an analysis was done to compare the energy required to recover a gram of ethanol for various feed stream concentrations. 2013-05-03T00:00:00Z http://hdl.handle.net/1813/33205 Title: Measurements of Cayuga Lake Production Authors: Nelson, Brittany Abstract: This study aims to compare estimates of primary productivity in Cayuga Lake based on in situ measurements of dissolved carbon dioxide (CO2) and dissolved oxygen (DO). Historically, productivity was estimated using the light/dark bottle method. More recent procedures have used in situ DO measurements. However, DO is a by-product of production. Directly using CO2 to determine productivity could offer a faster and more accurate result. Four locations at the southern end of Cayuga Lake were sampled between July 3, 2012 and October 9, 2012. Free aqueous CO2 was measured using an OxyGuard Dissolved CO2 meter. Citric acid was added to the water sample to lower the pH to the range of 3-4, so that most of the inorganic carbon would be in the CO2 form. Additionally, DO readings were taken using a Hydrolab DS 5. Average diel differences in CO2 and DO were found at each of the four sampling sites. To evaluate production, diel DO concentrations were corrected for atmospheric diffusion. In addition, diel CO2 differences were assumed to be adequate measures of production. Direct ambient CO2 concentration differences were found to have a strong, linear relationship with net ecosystem production. 2013-05-03T00:00:00Z http://hdl.handle.net/1813/33204 Title: An arsenic-specific biosensor with genetically engineered Shewanella oneidensis in a bioeletrochemical system Authors: Webster, Dylan Abstract: Genetically-engineered microbial biosensors have yet to realize commercial success in environmental applications, due in part to difficulties associated with transducing and transmitting traditional bioluminescent information. The use of bioelectrochemical systems (BESs) in biosensing applications allows for a direct electronic output that can be more easily incorporated into devices for remote environmental monitoring. Herein, we describe the first BES-based biosensor with genetically encoded specificity for a toxic metal. By placing an essential element of the metal reduction (Mtr) pathway of Shewanella oneidensis MR-1 under the control of an arsenic-sensitive promoter, we have engineered a strain that produces increased current in response to arsenic when inoculated into an BES. When operated as a chemostat with a hydraulic retention time of 7 h, our BES-based biosensor has a response time of 24 h and a lower detection limit on the order of 100 μM arsenite. To heighten the sensor's sensitivity to arsenic, we have begun characterizing an alternative sensing strain with improved translational efficiency. This ability to tune analyte sensitivity—along with the reliability of our continuous assay and the simplicity of the transcriptional circuit required for BES-based biosensing—suggests that similar sensing systems may be readily developed for both environmental deployment and on-line process control. 2013-05-03T00:00:00Z http://hdl.handle.net/1813/30794 Title: The Quantification of Liposome Signals Using Nanofiber-Based Microfluidic Devices Authors: Anderson, Caitlin E Abstract: Microfluidic paper-based analytical diagnostics have allowed for a diversification of analytical tools by enabling the development of inexpensive and portable devices that build upon existing detection strategies. Taking advantage of existing quantification techniques is an important strategy to ensure that these novel paper-based systems find use and application in the diagnostics world. For more than 50 years high-throughput assays have been developed using polymeric microtiter plates in which signals are quantified using specific absorbance, fluorescence, and luminescence readers. Here, we studied the novel idea of integrating a paper-based analytical assay with a microtiter plate reader. Specifically, electrospun nanofiber mats were designed to match dimensions and criteria of microtiter plate readers. Dye-encapsulating liposomes were used as a model analyte and quantified using absorbance and fluorescence detection strategies. Initially, positively charged poly(vinyl alcohol) (PVA) and polylactic acid (PLA) nanofibers were electrospun and functionalized in specific locations with anti-streptavidin antibodies. Additionally, streptavidin-conjugated liposomes were synthesized to encapsulate sulforhodamine B (SRB) (absorbance wavelength of 488 nm, and a fluorescence excitation and emission wavelengths of 540 nm and 590 nm respectively). Liposomes were then applied and flowed through the nanofiber mats under various conditions to investigate their selective capture, concentration, and detection. Primary investigations demonstrated the ability of PLA as an immobilization matrix to selectively bind streptavidin conjugated liposomes through the use of absorbance measurements. Fluorescence allowed subsequently for accurate readings without the interference of any of the assay materials. The ability to specifically quantify the capture of liposomes using the microtiter plate reader allowed for quantitative optimization of all involved assay steps and buffer systems to increase the reliability of the assay. In the end, the quantification of signals was achieved with a testing volume of 10 µL of SRB encapsulating liposomes, a wash step using 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES)-sucrose-saline buffer, and 2 µL of detergent for liposome lysis at a concentration of 50 mM. Thus, through the use of streptavidin-conjugated liposomes as a model analyte, it was demonstrated that a PLA nanofiber-based microtiter plate could successfully detect and differentiate between different concentrations of analytes with a detection limit of 0.5 mM and a sensitivity of 4023 Fluorescence units/mM. 2012-12-19T00:00:00Z http://hdl.handle.net/1813/29646 Title: Rapid and efficient mixing in low Reynolds number microfluidic systems via short-distance flow through an electrospun nanofiber mat: A computational analysis Authors: Georgescu, Andrei Abstract: This report presents the development of a comprehensive method by which electrospun nanofibers and their mixing effects may be modeled with a combination of custom scripts and ANSYS 14.0 software. A customizable and entirely automated workflow is realized, through which accurate models and results may be generated without requiring in-depth understanding of the underlying computational fluid dynamics principles. The automation process spans all simulation phases, starting with realistic fiber modeling via a custom script and followed by input specifications, automatic generation of the necessary geometry, export of the resulting computational mesh into ANSYS Fluent, control of computational solvers governing fluid flow and species mixing models, and ending with the automation of ANSYS CFD-Post to output solution data. This method is presented in a step-by-step manner through a case study of a Y-shaped microfluidic channel with an embedded electrospun nanofiber mat, the mixing performance of which is determined in this report's conclusion. 2012-08-09T00:00:00Z http://hdl.handle.net/1813/29620 Title: West King Road Stormwater Rehabilitation Project Authors: Licitra, Johnathan Abstract: The Town of Ithaca’s Public Works Department mission is to maintain the road infrastructure for commerce throughout the town. Part of this maintenance includes providing proper conveyance of stormwater—one such area that needs rehabilitation is along the intersection of West King Rd and Stone Quarry Rd in Ithaca, NY. This report discusses the background, hydrology, and 3 potential engineering solutions for the current erosion problem. After engineering capacity calculations and a material cost comparison, a weir and armored channel approach is recommended. 2012-08-03T00:00:00Z http://hdl.handle.net/1813/29619 Title: Evaluating the Impact of Energy Savings Technologies in The Statler Hotel Authors: Sani, Khadeejah Abstract: On average, hotels in America spend $2,196 per available room yearly on energy. In efforts to reduce energy costs, The Statler Hotel permitted Schneider Electric to test Cassia™, its energy management system. Cassia™ is an in-room energy solution based on sensors that detects room status and triggers temperature setbacks in heating and cooling units. In this study, a four-room test bed was used to evaluate potential energy savings associated with Cassia™. Statistical analyses were conducted to determine parameters’ influence in reducing energy units’ runtime. Results show that Cassia™ reduced runtime by 18%. While the average energy savings reported by Schneider Electric is 25-44%, this range includes savings from lighting, which was out of the scope of this study. By extrapolating savings from August-February 2012, a total of $7,829 would have been saved given a Cassia™ installation throughout the Hotel, while $3,003 saved solely based on vacancies during an unrented status. 2012-08-03T00:00:00Z http://hdl.handle.net/1813/29617 Title: Lifecycle Analysis of a n-caproate production system on an industrial scale Authors: Pichard, Christian 2012-07-25T00:00:00Z http://hdl.handle.net/1813/29539 Title: Investigating Neutral Theory in a Bacterial Community Authors: Clement, Sarah Abstract: The purpose of this study was to investigate whether a neutral model or non-neutral model dominate the formation of a microbial community. The microbial community that was considered was borrowed from the Werner et al. (13) study in 2011. The data included 16S rRNA sequences for nine anaerobic bioreactors treating brewery waste water. A lognormal distribution was used as the non-neutral model for this study. Using QIIME v1.5 (14) and Microsoft Excel, the best fit lognormal distribution was determined for each of the nine facilities. The R squared values were then calculated. For the nine facilities the R squared values ranged between 0.961 and 0.998. Therefore, the microbial communities in the nine facilities fit the non-neutral model, the lognormal distribution, well. 2012-07-03T00:00:00Z