Microalgae growth, lipid extraction and stable nanoemulsion productions for various industrial applications
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Algal oils are considered to be the promising alternative of natural source of energy, but the lipid accumulation and lipid productivity of microalgae is logistically difficult. This research overcomes the above challenges by culturing spirulina algae in ten gallon fish tank in laboratory with optimum growth conditions over a period of 40 days. Then, the lipid content was increased by growing microalgae in stressful conditions under low light and low nutrient supply. The easiest and cost effective method of harvesting was implemented. Thus, obtained algae biomass was sundried and 36% of oil was extracted using solvent extraction technique with a solvent mixture of about 100ml of chloroform and methanol in a ratio of 2 to 1 (v/v.) for every 5 grams of microalgae biomass. The research investigates the obtained algal oil with FT-IR and NMR technique to assess the functional groups, triglycerides, and fatty acids, and to prove the oil to be legible for further intended usage. Ultra-sonication technique was implemented on the algal oil in water mixed SDS (surfactant) to make stable nanoemulsions. Nanoemulsions, which were assessed through UVvisible technique, generated promising results, a maximum absorbance 2.63 at a wavelength of 346nm (λmax= 346nm). Nanoemulsions with different SDS concentrations and constant sonication time of 10 min depicted better results. The particle size analysis through DLS (Dynamic Light Scattering) was an important approach made in the research to perceive the meta-stable nature of nanoemulsions. The particle size of the algal oil was reduced to a 17.92nm when emulsified with 0.2 wt. % SDS in water and it remained stable. This study may open up new possibilities for developing nanoemulsions of algal oil for future applications in food related products, fuel blends and cosmetics as it has good absorbency rates and stability.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering