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영어

Since Korea is highly relying on imported fossil fuels for transportation, sourcing alternative renewable and eco-friendly transportation fuel remains highly pertinent. Long been microalgae are looked at as a suitable source of alternatives for fossil fuel and efficient CO2 mitigators. In spite of the remarkable advantages, microalgal biodiesel production still remains an expensive technology, and commercially viable large -scale algal production has yet to be achieved.This study focused on mass-cultivation of oleaginous microalgae under autotrophic and mixotrophic conditions with low-cost photobioreactors. Several species of microalgae from natural environments and microalgal culture bank were screened for their ability to grow autotrophically and mixotrophically (glucose/glycerol) with high CO2 concentrations (often 10% and coal-fired flue gas). As a result, a few microalgae spp. were identified with high growth rates and lipid content (~40 % to their dry cell mass). When the selected isolates were grown in 1 L bubble column under different nutritional modes, mixotrophic mode yielded the maximum growth when compared to the autotrophic or heterotrophic mode of cultivation. Several analyses are being instigated for detailed characterization of the cultivation of microalgal isolates, which includes; 18S rRNA gene sequencing, changes in pH and optical density of the culture, microscopic analyses (light microscopy, SEM and TEM analysis), estimation of lipid content, characterization of Fatty Acid Methyl Ester (FAME) profiles, estimation of carbohydrates, protein and chlorophyll, measurement of cell size/numbers, rate of glucose/glycerol consumption, rate of nitrate, phosphate and CO2 consumption, production of organic acid metabolites, and Denaturing Gradient Gel Electrophoresis (DGGE) for community analysis of epiphytic bacteria associated with microalgae in culture. For mass cultivation studies, photobioreactors were designed with transparent films and various prototypes of working volume 3 to 30 L are being evaluated for their efficiency to utilize CO2 and flue gas from a 2 MW coal power plant under indoor and outdoor conditions. This talk would discuss the recent experimental data and future directions of the study.