최적 배양 조건을 이용한 CO2 제거 목적의 담수 미세조류 Parachlorella kessleri의 바이오매스 생산성 향상

Abstract

This study attempted to improve the growth of the freshwater microalgae, Parachlorella kessleri, through the sequential optimization of culture conditions. This attempt aimed to enhance the microalgae's ability to fixate atmospheric CO2. Culture temperature and light intensity appropriate for microalgal growth were scanned using a high-throughput photobioreactor system. The supplied air flow rate varied from 0.05 to 0.3 vvm, and its effect on the growth rate of P. kessleri was determined. Next, sodium phosphate buffer was added to the culture medium (BG11) to enhance CO2 fixation by increasing the availability of CO2(HCO3-) in the culture medium. The results indicated that optimal culture temperature and light intensity were 20°C-25°C and 300 μE/m2/s, respectively. Growth rates of P. kessleri under various air flow rates highly depended on the increase of the culture's flow rate and pH which determines CO2 availability. Adding sodium phosphate buffer to BG11 to maintain a constant neutral pH (7.0) improved microalgal growth compared to control conditions (BG11 without sodium phosphate). These results indicate that the CO2 fixation rate in the air could be enhanced via the sequential optimization of microalgal culture conditions.