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Full-Text Articles in Life Sciences

The Synthetic Biology Of N2-Fixing Cyanobacteria For Photosynthetic Terpenoid Production, Charles T. Halfmann Jan 2017

The Synthetic Biology Of N2-Fixing Cyanobacteria For Photosynthetic Terpenoid Production, Charles T. Halfmann

Electronic Theses and Dissertations

In the last few decades, concerns over global climate change, energy security, and environmental pollution have been rising. To overcome these challenges, the concept of “-nth generation” biofuels has emerged as a strategy to convert solar radiation into fuels and bulk industrial chemicals for societal use, while decreasing our consumption of nonrenewable energy sources. Nitrogen-fixing cyanobacteria hold a distinct advantage in biofuel production over plants, given their ability to convert sunlight, air (CO2 and N2), and mineralized water to energy-dense carbon molecules, as well as fix atmospheric nitrogen gas into ammonia for metabolism. Engineered cyanobacteria with re-wired ...


Enhancing The Industrial Potential Of Filamentous Cyanobacteria, Tylor J. Johnson Jan 2016

Enhancing The Industrial Potential Of Filamentous Cyanobacteria, Tylor J. Johnson

Electronic Theses and Dissertations

The objectives of this project were to improve the industrial potential of filamentous N2-fixing cyanobacteria by increasing its biofuel tolerance, and to evaluate the economic feasibility and environmental impacts of a theoretical, cyanobacteria-based biofuel production facility. To develop a method to quantify filamentous cyanobacteria in dilute culture media, a dual-stained fluorescence assay was evaluated. While the viable cell stain (SYTO® 9) was accurate, the non-viable cell stain (propidium iodide) also bound to viable cells. Additional non-viable cell stains were evaluated, but none were accurate at quantifying viability. Thus we concluded that the viable cell stain SYTO® 9 is a reliable ...


Production And Harvest Of Microalgae In Wastewater Raceways With Resource Recycling, Alexander Colin Roberts Dec 2015

Production And Harvest Of Microalgae In Wastewater Raceways With Resource Recycling, Alexander Colin Roberts

Master's Theses and Project Reports

Microalgae can be grown on municipal wastewater media to both treat the wastewater and produce feedstock for algae biofuel production. However the reliability of treatment must be demonstrated, as well as high areal algae productivity on recycled wastewater media and efficient sedimentation harvesting. This processes was studied at pilot scale in the present research.

A pilot facility was operated with nine CO2-supplemented raceway ponds, each with a 33-m2 surface area and a 0.3-m depth, continuously from March 6, 2013 through September 24, 2014. The ponds were operated as three sets of triplicates with two sets continuously ...


Understanding And Improving Microbial Biofuel Tolerance As A Result Of Efflux Pump Expression Through Genetic Engineering And Mathematical Modeling, William James Turner Jan 2014

Understanding And Improving Microbial Biofuel Tolerance As A Result Of Efflux Pump Expression Through Genetic Engineering And Mathematical Modeling, William James Turner

Graduate College Dissertations and Theses

Recent advances in synthetic biology have enabled the construction of non-native metabolic pathways for production of next-generation biofuels in microbes. One such biofuel is the jet-fuel precursor α-pinene, which can be processed into high-energy pinene dimers. However, accumulation of toxic biofuels in the growth medium limits the possible fuel yield. Overexpression of transporter proteins such as efflux pumps can increase tolerance to biofuels by pumping them out of the cell, thus improving fuel yields. However, too many efflux pumps can compromise the cell as well, creating a trade-off between biofuel toxicity and pump toxicity. In this work we improve the ...


Biofuel Ethanol Production By Saccharomyces Bayanus, The Champagne Yeast, Kristen Miller Dec 2010

Biofuel Ethanol Production By Saccharomyces Bayanus, The Champagne Yeast, Kristen Miller

All Theses

The importance of biofuel ethanol is growing as the demand for clean, renewable fuels produced from non-food sources increases. The United States relies mainly on corn and the yeast Saccharomyces cerevisiae for the production of ethanol. A shift to cellulosic feedstocks, as the main source of biomass for ethanol production, would alleviate the pressure on farmers to produce corn for both the food industry and the ethanol industry. Example cellulosic feedstocks include switchgrass, sorghum, and canary grass. The cellulosic feedstocks are typically grown on land that cannot support economic food production, and thus lay unused.
For cellulosic feedstocks to be ...


Temperature Influence And Heat Management Requirements Of Microalgae Cultivation In Photobioreactors, Thomas Hagen Mehlitz Feb 2009

Temperature Influence And Heat Management Requirements Of Microalgae Cultivation In Photobioreactors, Thomas Hagen Mehlitz

Master's Theses and Project Reports

Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In ...