In recent years, fossil-based fuels have been used to supply the energy needs of the world. Fossil-based fuels induce accumulation of the atmospheric CO2 which causes global warming. One of CO2 source is flue gas emission from the power plant. The microalgae have been considered excellent biological materials for reduction CO2 with ability to photosynthesis. In this study, air, 10% CO2, 15% CO2 and simulated flue gas (containing 15% CO2) feed were used to observe effect CO2 concentration and flue gas on cell growth and lipid content of Chlorella protothecoides. The highest dry cell weight (1,5 g/L) and lipid content (45%) values were obtained with 15% CO2 feed while the highest growth rate (1,10 mu), biomass productivity (0,125 g/L/day), and lipid weight (0,63 g/g) were observed in 10% CO2 feed. Cultures fed with flue gas did not inhibited C. protothecoides growth and showed similar results with those fed with 15% CO2 gas in terms of growth rate, dry cell weight, biomass productivity and lipid content. These results showed that C. protothecoides has great potential for reducing CO2 emission from flue gas.