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Full-Text Articles in Engineering

Extraction Of Astaxanthin From H. Pluvialis Using Deep Eutectic Solvents, Roya Barzegar Oct 2018

Extraction Of Astaxanthin From H. Pluvialis Using Deep Eutectic Solvents, Roya Barzegar

Electronic Thesis and Dissertation Repository

Haematococcus pluvialis (H. pluvialis) is one of the main sources of astaxanthin, a high value carotenoid and a strong antioxidant. Astaxanthin extraction is hindered by the thick cell wall of H. pluvialis which is composed of sporopollenin. Mechanical cell disruption methods, high cost and energy-consuming, are required to enhance astaxanthin extraction. This study employed a novel technology using deep eutectic solvents (DESs) to demonstrate the possibility of direct extraction of astaxanthin without a disruption step. It was established that 68% of astaxanthin can be extracted from intact H. pluvialis cells using choline chloride-glycerol (ChCl-G) mixture with 12.5% (v/v ...


Hydrothermal Liquefaction Of Microalgae For The Production Of Bio-Crude Oil, Yulin Hu Apr 2018

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 ...


Investigation Of Lutein Production And Recovery From Chlorella Vulgaris Using Phototrophic Cultivation, Mengyue Gong Jul 2017

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 Jun 2017

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 Sep 2016

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 Aug 2016

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 ...


Polyhydroxybutyrate Production In A Photobioreactor Using Spirulina Platensis, Adrianna Mika Dec 2015

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. PHB ...


Study Of High Pressure Steaming On Lipid Recovery From Microalgae, Ana-Maria Aguirre Jul 2014

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 ...


Effect Of Plant Hormones On The Production Of Biomass And Lipid In Microalgae, Malihe Mehdizadeh Allaf Aug 2013

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 Jan 2013

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 production in ...


Experimental & Empirical Correlations For The Determination Of The Overall Volumetric Mass Transfer Coefficients Of Carbon Dioxide In Stirred Tank Bioreactors, Syeda Anam Kazim Aug 2012

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 (KLa) of carbon dioxide to quantify CO2 transfer from the gaseous to the liquid phase. Until now, finding KLa 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 KLa of CO2 in ...