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Studying the effect of different irradiances of light on the triacylglycerol yield in the marine diatom Thalassiosira pseudonana. Megan Snyder and Sam Huynh. Background Information. T. pseudonana is classified as phytoplankton (photosynthesizing marine organisms)
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Studying the effect of different irradiances of light on the triacylglycerol yield in the marine diatom Thalassiosira pseudonana Megan Snyder and Sam Huynh
Background Information • T. pseudonana is classified as phytoplankton (photosynthesizing marine organisms) • Diatom (microscopic, unicellular, photosynthetic algae with a silica shell called a frustule) • Bacillariophyceae class (largest group of biomass producers)100,000+ species • High oil content (21-31%) by dry weight • Entire genome is sequenced • Oil helps it float on the water to photosynthesize http://www.diark.org/img/species_pict/Thalassiosira_pseudonana_CCMP1335
Oil from diatom is a potential alternative fuel • Oil composed of lipids • Lipid: biological compound insoluble in water but soluble in organic solvents • Triacylglycerol (specific lipid) acts primarily as energy storage in diatoms (three fatty acids attached to one glycerol) • Triaclyglcerol is a non-polar, or neutral lipid • Polar lipids have a hydrophilic and a hydrophobic end; neutrals do not. • Polar lipids located in cell walls
TriacylglycerolTransesterification • process to refine triacylglycerol; how does it become biodiesel? • Oil is purified and reacted with methanol or ethanol in the presence of a catalyst (such as KOH potassium hydroxide or NaOH sodium hydroxide); the triacylglycerol is transformed to form esters and glycerol – remaining esters are biodiesel
Triacylglycerol Chemical Formula http://www.oliveoilsource.com/page/chemical-characteristics 3 Fatty Acids Glycerol
Nile red (9-diethylamino-5H-benzo[α]phenoxazine-5-one) is a dye that collects in the neutral lipids of living cells • Fluoresces under a certain wavelength, then emits another wavelength • The intensity of the fluorescence is directly correlated to lipid content
Purpose: increase the triacylglycerol content in the diatom using different light irradiances • Importance: increased triacylglycerol yields per diatom can make the process of making bio-fuel from algae more efficient and economically feasible
Irradiance: measure of light that reaches the product surface • Why measure in irradiance and not intensity? Photosynthesis depends on the amount of light reaching the surface of the plant, not the intensity of the source
Procedure • Diatoms will grow a plastic container under different irradiances of fluorescent light (test one irradiance at a time) • Sides of the container will be covered with aluminum foil to block out excess light • In previous experiments, irradiances of light have affected photosynthetic processes in T. pseudonana • Light on a 16 hour-on, 8 hour-off cycle, maintained by a light timer
Grown in f/2 agar, a solution that provides nutrients for marine algae • pH measured periodically with a Vernier probe to make sure CO2 levels stay constant • Container inside Styrofoam box with ice packs to keep temperature constant at about 53°F • Nile red stain will be applied to a few sample diatoms after six days
Data Collection • Use UV microscope equipped with a camera • Takes pictures of the cells fluorescing • Use Image J program to analyze level of fluorescence Inverted UV microscope Green Algae stained with Nile red- Triacylglycerol fluoresces yellow-gold, phospholipids fluoresce red http://www.chemistrytimes.com/Images/green_alga_with_nile_red.jpg http://accu-scope.net/3032_EPI_318CU.gif
Bibliography • Chemical Education Digital Library (2007 a). Polar Lipids. Retrieved from: http://chemed.chem.wisc.edu/chempaths/GenChem-Textbook/Polar-Lipids-1019.html • Chemical Education Digital Library (2007 b). Nonpolar Lipids. Retrieved from: http://chemed.chem.wisc.edu/chempaths/GenChem-Textbook/Nonpolar-Lipids-1018.html • Chen, W., Zhang, C., Song, L., Sommerfield, M., & Hu, Q. (2009). A high throughput Nile red method for quantitative measurement of neutral lipids in microalgae. Journal of Microbiological Methods, 77, 41-47. doi:10.1016/j.mimet.2009.01.001 • Demirbas, A. & Demirbas, F. M. (2010). Importance of algae oil as a source of biodiesel. Energy Conversion and Management. doi:10.1016/j.enconman.2010.06.055 • Epinoza, E. V., Nunez, R.M., Trees, C. C., et al (2007). Growth and accessory pigments to chlorophyll A ratios of Thalassiosira pseudonana (bacillariophyceae) cultured under different irradiances. Hidrobiologica, 17, 249-255. • Fromm, J. R. (1997). Introduction to Lipids. Retrieved from: http://www.3rd1000.com/chem301/chem302p.htm • Newman, S. (2008). Algae Biodiesel Engineering: Extracting Oil from Algae. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel2.htm • Reusch, W. (2004). Lipids. Retrieved from: http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/lipids.htm#lipid1 • Zhukova, N. V. (2003). Changes in the lipid composition of Thalassiosira pseudonana during its life cycle. Russian Journal of Plant Physiology, 51(5), 702-707.