Engineering Commons^™

Metabolic Engineering Of Cyanobacteria For Photosynthetic Production Of Drop-In Liquid Fuels, Bertram Michael Berla

McKelvey School of Engineering Theses & Dissertations

Cyanobacteria are oxygenic phototrophs with great potential as hosts for renewable fuel and chemical production. They grow very quickly (compared with plants) and can use sunlight for energy and CO2 as a carbon source (unlike yeast or E. coli). While cyanobacteria have been engineered to make many chemicals that are native and non-native parts of their metabolism, this work is concerned with the production of heptadecane in Synechocystis sp. PCC 6803. Heptadecane is in a class of natural products produced by all cyanobacteria, but in quantities insufficient for industrialization. Towards this future goal, we have built enabling systems for the …

A Passive Membrane Photobioreactor For The Isolated Cultivation Of Algal Resource Utilizing Selectivity (Icarus), With Wastewater As A Feedstock, Ivy Lea Cormier Drexler

USF Tampa Graduate Theses and Dissertations

Renewed momentum in the microalgae industry due to commercial interest in biofuels and bioproducts is driving the need to increase the economic competitiveness of large-scale microalgal production. Current knowledge of membrane systems common in other disciplines, such as environmental engineering, marine science, and biomedicine, are relevant to algae production. With pore sizes ranging from microns to angstroms, membranes provide tailored functions for solid/liquid separation (cell retention, biomass concentration and dewatering), gas/liquid separation (gas delivery and removal), and solute/liquid separation (bioproduct recovery, feedstock preparation and effluent recycling) that are problematic or not possible with other technologies. Though membranes have great potential …

Application Of Membrane Processes For Concentration And Separation Of Sugar Streams In Biofuel Production, Mohammadmahdi Malmali

Graduate Theses and Dissertations

The overall objective of this study was identification and development of a sugar concentration/separation membrane filtration unit to improve the bioconversion of lignocellulosic biomass into chemicals and fuels. This thesis is divided into three main parts. The first part is about our studies on the use of nanofiltration membranes for concentration of sugars in a lignocellulosic biomass hydrolysate. In addition, the feasibility of simultaneous removal of acetic acid, 5-(hydroxymethyl)furfural and furfural from the hydrolysate has also been investigated. The results obtained indicate that both concentration of sugars and removal of hydrolysis degradation products is feasible. However, careful selection of the …

Nanolayer Polymeric Coatings To Enhance The Performance And Service Life Of Inorganic Membranes For High Temperature-High Pressure Biomass Pretreatment And Other Applications, Vincent C. Kandagor

Doctoral Dissertations

Membrane technology has become increasingly attractive in several applications including water filtration, food industry, oil and gas, and biomedical applications. Most recently the quest for renewable, bioenergy has called for use of membranes in biomass pretreatment and other stages of producing biofuel. The success and advancement of the membrane technology for these various applications has, however, been impeded by the fouling of membranes, which causes the pores in the microporous structure to block, resulting in reduced efficiency, and in some cases, total failure of the membranes system. This challenge leads to a tremendous increase in the cost of using membranes …

Global Evaluation Of Biofuel Potential From Microalgae, Jeffrey W. Moody

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of the proposed work is to determine the productivity potential of microalgae around the world based on the current large uncertainty of the productivity
potential found in literature. To achieve this objective, a validated thermal and biological growth model was utilized coupled with weather data files from weather stations around the world. This enabled a realistic assessment of the productivity potential based on actual climatic variables. Sensitivity of microalgae lipid productivity to biomass production, temperature, and variability was performed illustrating the importance of biological and temporal resolution. Results from modeling work were leveraged for a scalability assessment based …

Lifecycle Assessment Of Microalgae To Biofuel: Thermochemical Processing Through Hydrothermal Liquefaction Or Pyrolysis, Edward P. Bennion

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microalgae have many desirable attributes as a renewable energy recourse. These include use of poor quality land, high yields, and it is not a food recourse. This research focusses on the energetic and environmental impact of processing microalgae into a renewable diesel. Two thermochemical bio-oil recovery processes are analyzed, pyrolysis and hydrothermal liquefaction (HTL). System boundaries include microalgae growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transportation to the pump. Two system models were developed, a small-scale experimental and an industrial-scale. The small-scale system model is based on experimental data and literature. The industrial-scale system model …

Lab-Scale Fast-Hydropyrolysis And Vapor-Phase Catalytic Hydrodeoxygenation For Producing Liquid Fuel Range Hydrocarbons From Intact Biomass, Vinod Kumar Venkatakrishnan

Open Access Dissertations

Liquid transportation fuels are primarily produced from petroleum-based non-renewable carbon sources. Sustainably available lignocellulosic biomass, as a renewable form of atmospheric carbon, could be utilized to produce hydrocarbon-based fuels with high energy density. One of the process options for this conversion is the H2Bioil process, where biomass is rapidly heated in a hydrogen environment to produce fast-hydropyrolysis vapors that are catalytically upgraded in downstream hydrodeoxygenation (HDO) to produce hydrocarbons. This process has been modeled to have high carbon and energy efficiencies of ~70% and ~75%, respectively.

This dissertation presents the results of a lab-scale experimental proof-of-concept for the H2Bioil process …

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 …