In this project, novel technology for using microalgae to fix CO2 in industrial flue gas was developed. Five local species of microalgae, including both from fresh and salt water origins, were screened under high- and medium-temperature culture conditions. The species identified by DNA sequencing were Synechococcus #CS1, Cyanidioschyzon #YM1, Dunaliella #KP1, Chlorella #AS8, and Chlorella #AS6. After a series of tests, Synechococcus #CS1 and Chlorella #AS8 were identified to be the potential organism, which grew optimally at 50°C and 35°C, respectively.
Under temperature below 35°C, Chlorella #AS8 exhibited a higher growth rate than Synechococcus #CS1, whereas a lower rate when above 40°C. Under such condition, a maximum biomass of about 0.15 g L-1 at day 6th of incubation was obtained. However, the magnitude of biomass varied with the initial concentration of algae used for cultivation. From experiments, the basic requirement of macro-nutrients for getting algal biomass was calculated. For mass production, an integrated system, combining photoreactors with a stable temperature controller and illumination was proposed. Basically, the harvested algal biomass can be used as fish or shrimp meal. However, a further study of potential usage of algal biomass for health food or pharmaceutical purpose should be done. Basing on the present study, six suggestions are proposed for further exploiting the utilization of algae in order to optimize CO2-fixation of flue gas in Taiwan.