Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Co-Production of Chitin Nanofibers, Proteins, and Lipids in Marine Diatoms Belonging To the Thalassiosira Genus(Izmir Institute of Technology, 2022) Sezgin, Tuğçe; Özkan, Altan; Özkan, AltanChitin is a biopolymer used in various industries, including biomedical, pharmaceutical, medical, and food. Today, the vast majority of chitin is obtained from waste shellfish. Shellfish chitin has an inherent impurity problem because chitin in these organisms is embedded in other organics and inorganics. Thus, new sources have been investigated. Diatoms, particularly Thalassiosira and Cyclotella species, have the potential to be the providers for applications requiring high quality through their unique ability to biosynthesize and extrude chitin nanofibers. The primary aim of this study is to study this potential. This investigation entailed the cultivation of three Thalassiosira strains according to a standard cultivation protocol under photobioreactor conditions. The secondary aim was to assess the possibility of commercially valuable co-product generation. For this, biomass protein, lipid, and fatty acids contents were analyzed. Chitin productivity varied significantly between the strains. The peak productivities and final concentrations ranged from 4 to 25 mg/L-day and from 60 to 250 mg/L, respectively. Average fiber diameters ranged from 68.5 to 95.0 nm. Silicon limited growth increased the chitin biosynthesis in T.weissflogii 1336 and T.pseudonana 2135. Biomass lipid contents of over 45% were obtained with T.pseudonana 2135 under silicon depletion. The fatty acid profiles indicated the suitability for application as live aquaculture feed for T.weissflogii 1336, and biodiesel feedstock material for T.pseudonana 2135. The highest biomass protein contents were about 30%, which were obtained under silicon availability. This study, for the first time, assessed the chitin productivity of Thalassiosira strains and demonstrated unique multiproduct generation scenarios.Master Thesis Effect of Co2 Concentration and Temperature on Growth Rate and Lipid Content of Isochrysis Galbana(Izmir Institute of Technology, 2012) Umdu, Sabrettin; Tokatlı, FigenThe lipid production and biomass growth of microalgae Isochrysis galbana was investigated under the effects of different medium temperature and carbon dioxide levels. Algae production was studied in ten-liter, open-air, aerated bioreactors and sampling was done daily to monitor the cell growth. At the end of each fermentation, the dry mass, lipid amount and fatty acid profiles were determined. The algae were grown according to designed experiments (central composite design (CCD)) at 15, 22.5 and 30 °C medium and aerated with air containing 5, 10 and 15% v/v CO2. It was observed that in 15 °C experiments, the fatty acid profile was formed mainly by unsaturated fatty acid (both mono and poly unsaturated) and the amount of saturated fatty acids increased by increased CO2 levels. The saturated fatty acid content increased with increasing growth temperature. Dominantly observed fatty acids are Pentadecanoic Acid (C15:0), Pentadecanoic Acid (C15:0), Palmitic Acid (C16:0), Linolenic Acid (C18:3), Oleic Acid (C18:1). In the algal productions performed at 22.5 °C and 30 °C medium conditions, the fatty acid content was mainly formed by saturated fatty acids. However, the amount of lipid produced increased with increasing temperatures. The highest cell growth was seen at 15 °C experiments. The lowest growth rate was observed at 30° C experiments. It was observed that the medium temperature had the largest effect for the production of saturated and unsaturated fatty acids. The carbon dioxide was found effective linearly on the fatty acid production.