Engineering Commons^™

Adaptive Laboratory Evolution Of Scenedesmus Obliquus For Increased Carbohydrate Content And Biomass Productivity, Nahel Ali

Master's Theses

The economics of microalgal bioproduct commercialization would benefit from increased accumulation of energy storage compounds, such as carbohydrates and lipids, and increased biomass productivity. This thesis explores two adaptive laboratory evolution strategies for improving Scenedesmus obliquus: single UV-mutagenesis and low light cultivation at a high dilution rate to produce cultigens with greater carbohydrate content and iterative UV-mutagenesis and selection under outdoor conditions in a raceway pond at a high dilution rate to increase biomass productivity.

Two cultigens were generated with the goal of increased carbohydrate content: K5 and K7. Both were mutagenized for 5 seconds and cultivated in 50-mL …

Methods To Increase Algae Biomass Productivity In Raceway Pond Monocultures, Ryan S. Anderson

Master's Theses

The economics of algae biofuels and bioproducts would be improved by increased biomass productivity. Two studies on this potential are described in this thesis – one on a locally isolated filamentous yellow-green alga and the other on a planktonic strain genetically improved via selective enrichment.

Polycultures have been viewed as productive, stable, and, in some cases, harvestable by natural bioflocculation. Local native strains might have higher productivity than culture collection strains because they are already adapted to local outdoor conditions. In this study, the filamentous yellow-green alga Tribonema minus was isolated from a local volunteer polyculture. Its productivity as a …

Optimization Of Biogas Production By Use Of A Microbially Enhanced Inoculum, Anna Doloman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A renewable energy source, biogas, comprises of methane (80%) and carbon dioxide (15%), and is a great alternative to the conventional fossil-based fuels, such as coal, gas and oil. Biogas is created during anaerobic biological digestion of waste materials, such as landfill material, animal manure, wastewater, algal biomass, industrial organic waste etc. A biogas potential from organic waste in the United States is estimated at about 9 million tons per year and technology allows capture of greenhouse gases, such as methane and carbon dioxide, into a form of a fuel. In the light of global climate change and efforts to …

Nutrient Limitation Of Algal Growth In Fishery Lakes, Madeline Ludwig

Biological and Agricultural Engineering Undergraduate Honors Theses

This study investigated the effect of nutrient addition on algal growth in three United States Forest Service lakes for fishery management in Arkansas. In fishery managed lakes, fertilization works by manipulating algae growth, a basal food resource in lakes, to promote the growth of the fish population. For the nutrient addition experiments, water was collected from each lake in cubitainers and spiked with nutrients; the treatments included the control, nitrogen (+N), phosphorus (+P), and nitrogen and phosphorus (+N +P). When algal growth was visually observed, a water sample was collected from each cubitainer and analyzed for chlorophyll-α. The results showed …

Anaerobic Co-Digestion Of Algal Biomass And A Supplemental Carbon Source Material To Produce Methane, Yousef Soboh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The demand on alternative energy is rapidly increasing because the reserves of conventional fuel are decreasing and their impacts on the environment are increasing.
Developing renewable energy sources should receive utmost attention. The production of biofuels like methanol, biodiesel, and methane from various kinds of abundant biomass represents a very attractive energy source that can reduce the dependence on conventional fossil fuels energy.

Since algae contains high amounts of nitrogen and low carbon content, this research focused on anaerobic fermentation of algae to produce methane by blending algae with a supplemental carbon source material, sodium acetate. This was done to …

Evaluation Of The Performance Of A Downward Flow Inclined Gravity Settler For Algae Dewatering, Dustin D. Bowden

ETD Archive

With recent concerns over the environmental implications of burning fossil fuels coupled with the depletion of fossil fuel reserves an alternative source of energy isneeded. Algae derived biofuels may be an effective replacement for transportation fuels as they are carbon neutral and have a high area productivity. Algae is superior to terrestrial plants as a biofuel source due to its high oil productivity and efficiency along with the fact that it will not displace food production. Currently the largest obstacle to the implementation of commercial algae to biofuel processes is algae dewatering. The separation of algae from water is difficult …

Computational Fluid Dynamics Modeling Of A Gravity Settler For Algae Dewatering, Scott A. Hug

ETD Archive

Algae are the future of lipid sources for biodiesel production. Algae can produce more biodiesel than soybean and canola oil and can be grown in more diverse locations. Algae concentrations are naturally around 0.1 by weight. Enough water must be removed for the algae level to reach 5 , the minimum concentration in which lipids can be used in the transesterification process for biofuel production is 5 . Current dewatering methods involve the use of settling tanks and centrifugation. The costs of centrifugation limit the commercial viability of algae based biodiesel. A novel inclined gravity settler design at Cleveland State …

Algal Biofilm Production And Harvesting System For Wastewater Treatment With Biofuels By-Products, Logan Christenson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Excess nitrogen and phosphorus in discharged wastewaters can lead to downstream eutrophication, ecosystem damage, and impaired water quality that may affect human health. Chemical-based and physical-based technologies are available to remove these nutrients; however, they often consume significant amounts of energy and chemicals, greatly increasing treatment costs. Algae are capable of removing these pollutants through biomass assimilation, and if harvested, can be utilized as a feedstock for biomethane or biodiesel production. Currently, difficulties in harvesting, concentrating, and dewatering algae have limited the development of an economically feasible treatment and production process. When algae are grown as surface-attached biofilms, the biomass …

Quantification Of Scenedesmus Dimorphus Growth And Substrate Kinetics For Continuous Photobioreactor Design, Daniela Ribita

ETD Archive

Increasing gas prices, limited fossil fuel resources and U.S. dependence on foreign oil make research in alternative fuels a priority. The feasibility of producing fuels from microalgae is economically dependent on improvements in lipid productivity by the algae. The research presented here focuses on the development of a mathematical model to describe the biomass and lipid productivity in a continuously-operated photobioreactor (PBR) system. Five different cell lysing methods were evaluated for the purpose of improving the methods of analysis of lipid synthesis. The two most promising methods were found to be mortar and pestle and organic solvent cell fractionation methods. …

Algea Suspension Dewatering With An Inclined Gravity Settler, Jing Hou

ETD Archive

Biofuel has been studied for several decades as a feasible substitute for petroleum, which may solve the energy crisis. Having a high oil content and growth rate, algae biofuels have received lots of attention recently, and have been considered as one of the most promising technologies to reduce the dependence of fossil fuels. In the process of producing algae biofuel, the dewatering process constitutes a significant part of the cost of the algae biofuel, impeding progress towards large-scale commercial use. An inclined settler utilizes gravity to separate algae cells from the fluid, with little energy consumption. The separation ability of …