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영어

Chlorella sp. was grown with organic carbon source as glucose under mixotrophic conditions and CO2, to maintain mass amounts of biomass for biodiesel production. The cells were cultured in a 14 ℓ photo-bioreactor at 30℃ with illuminating light intensity of 30 μE/(m2s). CO2 was constantly supplied at a rate of 250 (ml/min) at an agitation speed of 150 rpm. The optimal concentration for mixotrophic growth was determined as 10 g/L. 10 g/L of glucose was found to be most proper carbon source, maintaining 5.3 (g-dry wt./L) of cell concentration and 17.2 (%, w/w) of total lipid for 90 days cultivation. Particularly, higher glucose concentration than 10 g/L showed the decrease of cell concentration and total lipid production. The cases of mixotrophic growth supplied glucose(10 g/L), cell concentration(5.3 g-dry wt./L) and total lipid production(17.2 %, w/w) were observed. For autotrophic growth, 2.3 (g-dry wt./L) and 10.3 (%, w/w) were observed for maximum cell concentration and total lipid production, respectively. After 45 days cultivation, nile red staining of Chlorella sp. grown with glucose was showed neutral lipids including hydrocarbons and triglycerides stained in yellow, while polar lipids did not almost exist. This study confirmed that optimal concentrations of glucose as an organic substrate to maintain high cell growth and lipid composition.