This paper discusses the problem of producing biomass fuels using alga expected as future biomass fuels. Based on the result of the basic culture experiment, the culture system using 100 L semicircular shaped water tank was developed in order to examine the culture environment. We examined some of the important elements needed to improve the algae growth: measurement and improvement of the quantity of photon, the measurement of CO2 dissolution behavior and its dissolution ability, and the flow in the water tank. Finally, the environmental load of the culture system was calculated using Life Cycle Assessment (LCA). We found: 1) by improvement of the reactor setup, the photon quantity more than 140 μmol m-2 s-1 was achieved; 2) CO2 dissolution efficiency was high when the algae were inside the tank. In addition, we found that the bubbling device in the semicircular water tank has the ability for enough stirring in water tank. Finally, it was confirmed from the calculation results that there was still a lot of CO2 emission even with this improvement.
