Engineering Commons^™

The Effect Of Steam Explosion On Lipids Extraction From Microalgae And Derivation Of Pectin Films From Waste Culture, Shahil Chhiba

Electronic Thesis and Dissertation Repository

The objective of this study was to investigate the properties of sustainable replacements for plastics and diesel fuel, derived from microalgae (Chlorella vulgaris) subjected to steam explosion. During the process, oven temperatures of up to 500 °C were reached, with the experiments left for different times after reaching their maximum internal temperature. Lipids were extracted from algal cultures using a modified Folch method. The waste microalgae were combined with pectin and glycerol to form biodegradable films, and their solubilities and tensile strengths were measured. The highest yield was 124 mg lipids/g microalgae from 400 °C steam explosion for …

Co2 Derived Carbon Capture Using Microalgae In A Photobiocrec Unit, Maureen D. Cordoba Perez

Electronic Thesis and Dissertation Repository

Microalgae has the potential to contribute to carbon dioxide capture, resulting in the production of alternative fuels and valuable chemical products. To accomplish this, high-efficiency photobioreactors must be conceptualized, designed, and established, in order to achieve high inorganic carbon conversion, superior light utilization, and unique fluid dynamics.

In this PhD Dissertation, experiments with Chlorella vulgaris were carried out, in a 0.175L especially designed PhotoBioCREC unit, under controlled radiation and high mixing conditions. This unique design involves 1 mm-2 mm alumina particles, which keep photoreactor walls always clean, without compromising photon transmittance. Sodium bicarbonate (NaHCO₃) was supplied as the …

Investigative Study Of Microalgal And Electrochemical Wastewater Treatment Systems And Modeling Of The Wafer-Enhanced Electrodeionization Using Supervised Learning, Humeyra Betul Ulusoy Erol

Graduate Theses and Dissertations

Wastewater has a serious impact on environment and public health due to its high concentration of nutrients and toxic contaminants. Without proper treatment, excess nutrients discharged in wastewater can cause a damage to the ecosystem such as undesirable pH shifts, cyanotoxin production, and low dissolved oxygen concentrations.

Main objectives of this dissertation work were to investigate i) the biofuel potential of P. cruentum when grown in swine wastewater, ii) the influence of four most commonly used ion exchange resins on the system efficiency and selectivity for the removal of sodium, calcium, and magnesium ions, and iii) the modeling of wafer-enhanced …

Value-Added Lipids Extraction From Wet Microalgae Using Ionic Liquids, Yujie Zhang

Electronic Thesis and Dissertation Repository

Microalgae have gained interest as sources of renewable lipids in the biofuel sector due to their ability to sequester carbon dioxide into triacylglycerol (TAG), a biodiesel feedstock. However, industrial-scale production of microalgae exclusively for fuel production is limited by technical and economic challenges. Some marine microalgae can accumulate large amounts of polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and other unsaturated fatty acids, which are high-value compounds linked to the prevention of various cardiovascular diseases. This thesis therefore examines the extraction of lipids and DHA from two microorganisms (Chlorella vulgaris, a model organism for lipid production, …

Bioremediation Of Refinery Desalter Effluent Using Debaryomyces Hansenii And Parachlorella Kessleri, Leila Azimian

Electronic Thesis and Dissertation Repository

Crude oil desalting operations produce an effluent stream which is challenging to treat due to its salt, heavy metal and hydrocarbon content. Consequently, desalter effluent (DE) is usually diluted into other effluent streams and sent to conventional wastewater treatment plants which may lead to upsets the plant operation.

In this study, a novel microbial approach was applied which investigated DE treatment using halotolerant yeast Debaryomyces hansenii (LAF-3 10 U) or the environmentally robust micro-algae Parachlorella kessleri strain CPCC 266. The effect of these two different approaches on both synthetic and actual DE was investigated in both batch and/or continuous mode. …

Lipid Extraction From Spirulina Sp. And Schizochytrium Sp. Using Supercritical Co2 With Methanol, Shihong Liu, Husam A. Abu Hajar, Guy Riefler, Ben J. Stuart

Civil & Environmental Engineering Faculty Publications

Microalgae are one of the most promising feedstocks for biodiesel production due to their high lipid content and easy farming. However, the extraction of lipids from microalgae is energy intensive and costly and involves the use of toxic organic solvents. Compared with organic solvent extraction, supercritical CO₂ (SCCO₂) has demonstrated advantages through lower toxicity and no solvent-liquid separation. Due to the nonpolar nature of SCCO_2, polar organic solvents such as methanol may need to be added as a modifier in order to increase the extraction ability of SCCO₂. In this paper, pilot scale lipid …

Hydrothermal Liquefaction Of Microalgae For The Production Of Bio-Crude Oil, Yulin Hu

Electronic Thesis and Dissertation Repository

Due to the depletion of fossil fuels and climate change, extensive research has performed towards renewable energy production from microalgal biomass. Microalgae have several inherent benefits, such as high photosynthetic efficiencies, fast growth rates, and high lipid contents. In addition, microalgae can be cultivated in the non-arable lands (e.g., saline and waste water), thereby no competition with food crops production.

Transesterification is the one of commonly used technologies for converting microalgae into liquid bio-fuels (i.e., biodiesel). Normally, an energy-intensive drying step is required in the transesterification treatment, which accounts for nearly half of the energy input. Hence, if “wet” microalgal …

Investigation Of Lutein Production And Recovery From Chlorella Vulgaris Using Phototrophic Cultivation, Mengyue Gong

Electronic Thesis and Dissertation Repository

Microalgae have been recognized as a natural reservoir of the valuable commercial carotenoid lutein due to its high lutein content and fast growth cycle. However, the production of lutein from microalgal sources is not yet sufficiently cost-effective to compete with traditional marigold flower-based processing (Park et al., 2015). This thesis aims to investigate the factors affecting lutein production and recovery from microalgae using a phototrophic cultivation mode.

The closed photobioreactors can offer controlled conditions for faster microalgae growth. A coiled tubular tree photobioreactor (CTPBR) design was first investigated for cultivating the cold tolerant microalgae, Chlorella vulgaris UTEX 265, under various …

Magnetic Stimulation On The Growth Of The Microalga Nannochloropsis Oculata, Manuella Oliveira

Electronic Thesis and Dissertation Repository

Fossil fuels, our principal sources of energy supply, are non-renewable and research is needed on alternatives that are renewable and potentially more environmentally friendly. Microalgae have been investigated as a future feedstock alternative to petroleum but the technology is still expensive and improvements are needed. Reduction in costs might be achieved by increasing algal biomass and lipid productivity. The lipids can be used to produce biofuels such as biodiesel and biojet fuel. The marine microalga Nannochloropsis oculata grows well and can accumulate high lipid content. In this study, the effects of static magnetic field stimulation (SMF) of 0 (control), 5, …

Abe Fermentation From Low Cost Substrates, Kai Gao

Electronic Thesis and Dissertation Repository

The high cost of substrate and product inhibition in the fermentation broth remains two major problems associated with bio-butanol production. This thesis aims to solve these problems by examining abundant lignocellulosic biomass as potential feedstocks and exploring novel substrates such as carbohydrates derived from microalgae for ABE fermentation. The commonly observed toxic effect after pretreatment of lignocelluslosic biomass was removed by resin adsorption, where the resin could also serve as an in-situ butanol recvoery devices.

Corn cobs (an agricultural waste), switchgrass (an energy crop) and phragmites (an invasive plant in North America) were investigated as substrates for ABE fermentation by …

Direct Conversion Of Wet Microalgae And Oleaginous Yeast To Biodiesel Using Ionic Liquids, Valerie Orr

Electronic Thesis and Dissertation Repository

This thesis examined the development of an oleaginous yeast or microalgae based biorefinery process. First, improvements were made to the Nile Red assay, a high-throughput method for monitoring lipid accumulation in oleaginous organisms resulting in a significantly more reproducible and accurate assay. This assay was then used to optimize lipid production during heterotrophic cultivation of microalgae on glucose using response surface methodology resulting in microalgae with high lipid content (37.6% wt.). In order to improve the renewability of heterotrophic lipid production, both oleaginous yeast and microalgae were cultivated using pyrolytic sugars, produced via fast pyrolysis of pinewood waste. The effects …

Polyhydroxybutyrate Production In A Photobioreactor Using Spirulina Platensis, Adrianna Mika

Electronic Thesis and Dissertation Repository

Biopolymers and other naturally derived chemicals continue to gain attention over petrochemical based products due to the price volatility of crude oil, increasing need to reduce greenhouse gas emissions and public awareness of environmental issues. Cyanobacterium Spirulina (Arthrospira) platensis, a commercially feasible blue-green alga, is able to synthesize poly(3-hydroxybutyrate) (PHB), a biodegradable and biocompatible polymer, as an energy storage product of photosynthesis directly from CO₂. A flat plate photobioreactor (PBR) with LED illumination was designed for the cultivation of S. platensis. Computational fluid dynamics (CFD) software was used to improve airflow uniformity and mixing in the …

Photobioreactor Design For Improved Energy Efficiency Of Microalgae Production, Alexander Burns

Master's Theses

ABSTRACT

Photobioreactor Design for Improved Energy Efficiency of Microalgae Production

Alexander Burns

The objective of this research was to investigate a new photobioreactor (PBR) design for microalgae production that retains the typical advantages of existing tubular PBRs while reducing power consumption by providing simultaneous culture circulation and gas exchange with airlift alone and no centrifugal recirculating pump. Traditional tubular PBR designs feature a compressed air supply and a centrifugal pump for culture circulation and gas exchange. Circulation and gas exchange in a closed-system PBR is necessary to keep the algae suspended and to provide sufficient mass transfer (mainly for the …

Study Of High Pressure Steaming On Lipid Recovery From Microalgae, Ana-Maria Aguirre

Electronic Thesis and Dissertation Repository

Sustainable and clean fuels are in demand due to the perceived negative effects on health and environment with current use of fossil fuels. Lipids from microalgae offer a potential approach to obtain sustainable biofuels. In this study a two step process was adopted: investigation of culture conditions to find optimal points for lipid productivity and cellulose content, followed by an investigation of microalgae disruption for lipid recovery.

In the first phase of the research the effect of culture conditions on Chlorella vulgaris biomass concentration and the ratio of lipid productivity/cellulose content were studied. Response surface methodology was applied to optimize …

Effect Of Plant Hormones On The Production Of Biomass And Lipid In Microalgae, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Limited fossil fuel reserves, increasing demand for energy in all parts of the world are some driving forces to look for new sources of transportation fuels. Among different options available, microalgae are currently attracting wide interests as an alternative and renewable fuel source.

Microalgae are single cell photosynthetic organisms that are known for rapid growth and high energy content and as a part of photosynthesis; they produce oil that can be used as a feedstock for biodiesel production. Some algae strains could contain lipid up to 80% of the dry biomass. The amount of lipid production is in direct relation …

Batch And Continuous Studies Of Chlorella Vulgaris In Photo-Bioreactors, Claudia Sacasa Castellanos

Electronic Thesis and Dissertation Repository

Microalgae are unicellular, photosynthetic microorganisms, they have minimal nutrient requirements and are being used as source materials for a variety of products such as protein rich nutritional supplements, pharmaceutical chemicals and pigments (used in food and cosmetics). They also grow extremely fast, in comparison to plants and many microalgae strains are exceedingly rich in oil which makes them great candidates for the production of biodiesel. The strain Chlorella vulgaris, has shown a great promise as a source of oil and as being able to help in the treatment of wastewater. Despite all the advantages , the high cost of …

Experimental & Empirical Correlations For The Determination Of The Overall Volumetric Mass Transfer Coefficients Of Carbon Dioxide In Stirred Tank Bioreactors, Syeda Anam Kazim

Electronic Thesis and Dissertation Repository

One of the most important parameters to cultivate microalgae is carbon dioxide absorption by microalgae. Therefore, it is necessary to determine the overall volumetric mass transfer coefficient (K_La) of carbon dioxide to quantify CO₂ transfer from the gaseous to the liquid phase. Until now, finding K_La of CO₂ for microalgae cultivation has been a challenge as there is not much information available about it in the literature and most of the time the CO₂ transfer to microalgae is approximated. In this study, correlations to directly calculate K_La of CO₂ in …

Airlift Column Photobioreactors For Porphyridium Sp. Culturing: Part I. Effects Of Hydrodynamics And Reactor Geometry, Hu Ping Luo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Photosynthetic Microorganisms Have Been Attracting World Attention for their Great Potential as Renewable Energy Sources in Recent Years. Cost Effective Production in Large Scale, However, remains a Major Challenge to overcome. It is Known to the Field that Turbulence Could Help Improving the Performance of Photobioreactors Due to the So-Called Flashing Light Effects. Better Understanding of the Multiphase Fluid Dynamics and the Irradiance Distribution Inside the Reactor that Cause the Flashing Light Effects, as Well as Quantifying their Impacts on the Reactor Performance, Thus, Are Crucial for Successful Design and Scale-Up of Photobioreactors. in This Study, a Species of Red …

A Critical Review On Recent Methods Used For Economically Viable And Eco-Friendly Development Of Microalgae As A Potential Feedstock For Synthesis Of Biodiesel, Yogesh C. Sharma, Bhaskar Singh, John Korstad

College of Science and Engineering Faculty Research and Scholarship

Microalgae are being considered as a viable feedstock for large-scale production of biodiesel. However, though it may look simpler to obtain lipids from microalgae, the overall process of choosing an algal strain, cultivation, harvesting, dewatering, and extraction of oil is quite complicated and not economically prudent at this time. A thorough understanding of algae and the overall biodiesel production process discussed in this paper is vital so that focused research might lower the costs involved. Various diverse species of microalgae are currently being used as feedstocks for biofuel. Heterotrophic culture may be preferred over photoautotrophic cultivation. For cultivation, specially fabricated …

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

Master's Theses

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 addition, …