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영어

As the price of conventional fossil fuels rise, renewable liquid fuels have become more attractive. Lipids from marine microalgae draw a lot of interests as a feedstock for biodiesel. Among various factors affecting marine microalgal culture other than light-related parameters, CO2 concentration, salinity and temperature found to be the important factors affecting the biomass and lipid production of Dunaliella tertiolecta. In order to examine the influence of these factors on cell growth and lipid production, D. tertiolecta has been cultivated under a certain range of CO2 concentrations (Air and 2, 5, 10% CO2 enriched air), salinities (2 ~ 4% with 0.5% interval) and temperature (5, 10, 15, 20, and 25℃) in 0.4 L bubble column photobioreactors (PBRs). The results indicated that the growth rate and biomass were the highest at 2% CO2. When the cells grew without CO2 enrichment, pH was increased from 6.5 to 10 and the elevated pH induced the cells to attach on the PBR wall. D. tertiolecta grew well in the range of 15~25℃ showing the optimal growth at 21℃ but the strain cannot survive below 10℃. The highest final dry cell weight (DCW) was observed at 2% salinity. Lipid contents per DCW, however, became higher as the salinity increase till 4%, while the final cell concentration decreased as the salinity increased. Salt stress (salt shock) was also examined at mid-log phase resulting the lipid content from 51.4% to 57.3% without biomass loss. As a result, salt shock may be a better practice than maintaining high salinity during the entire culture.