Biochemical and genetic assessment of high value lipid production from local thermo-resistant green microalgae strain


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: DİLAN AKIN

Danışman: AYŞE MERAL YÜCEL

Özet:

Green microalgae are a rich source of lipids available for animal and human consumption and for an important form of bioenergy; biodiesel. Selection and genetic engineering of a microalgal strain for sustainable and low-cost biotechnological processes is of utmost importance. In this study, a novel thermo-resistant microalgae strain; Scenedesmus sp. METUNERGY1402 (ME02) was assessed for high-value lipid production via biochemical and genetic approaches. An optimized growth medium for efficient growth of Scenedesmus sp. ME02 has been developed. In terms of biochemical and physiological aspects of microalgae, temperature is critical parameter in cultivation of microalgae and temperature control vi presents an additional cost in outdoor bioreactors. Previously, Scenedesmus sp. ME02 was reported to survive at 25-50°C. This study showed that this strain could also withstand temperatures as low as 10°C. The effects of diurnal temperature fluctuation on biomass and lipid productivities of Scenedesmus sp. ME02 were examined and compared to other temperature regimes. Fatty acid methyl ester (FAME) profiles of Scenedesmus sp. ME02 at different temperatures was also investigated in this study. Significant changes were observed particularly in economically important FAME profiles (palmitic, stearic, oleic, linoleic and linolenic acids). In order to dissect the genetic basis of the changes in fatty acid composition, fatty acid desaturase-2 (fad2) gene was identified and partially cloned from Scenedesmus sp. ME02. Finally, Scenedesmus sp. ME02 was successfully and stably transformed via genetic engineering technology. This is the first report of such a laboratory set-up implemented in batch cultures that can provide an insight for outdoor cultivation under extreme temperatures.