미세조류 배양을 위한 평판형 광생물반응기에서의 성장조건 최적화에 관한 연구

Abstract

n recent years, the demands of bioenergy utilization are increased as the importance of environmental conservation become bigger. At first, the mass cultivation and high concentration of microalgae using photobioreactor are required in order to convert bio resources to applicable energy source. The open-pond system were developed to improve the microalgae cultivation and massively operated for the product derived from a lot of micro-organisms. However, in the aspect of the efficiency of light utilization, the closed photobioreactor system is far superior than open-pond. The recently developed flat-panel photobioreactor can efficiently cultivate microalgae in the small space. For the reason many researchers are focusing on the development of this system. In this study, the effect of the structure and the size of photobioreactor is investigated in order to obtain the optimal culture conditions of microalgae and scale-up of the reactor. Chlorella is selected based on the lipid-rich and easy-to-cultured. The flat-panel photobioreactor with the various size, which are 5 L, 15 L, 25 L, and 50 L are fabricated and two types of 15 L photobioreactor with the different structure are constructed. Chlorella was cultivated in both the photobioreactor with blade and without blade to investigate the effect of structure. The experimental result shows that the bioreactor with blade showed rapider growth rate of Chlorella than the reactor without blade. This result means that the light source could be effectively provided to Chlorella in the photobioreactor with blade because of the active circulation of CO2 and medium, and non(or minimum)-precipitation. Therefore, the airlift system and the static stirring system should be applied to photobioreactor for the high condensed cultivation. The experiment which investigates the relationship between the size of photobioreactor and the grows rate of Chlorella is performed to verify the feasibility of scale-up. The flat-panel photobioreactors with 5 L, 25 L, 50 L capacity and the same structure are used. According to the result, it is verified that the smaller photobioreactor, the rapid growth rate was shown since the higher density of Chlorella makes the light penetration ratio smaller. However the difference of growth rate was insignificant. Therefore, it is expected that the bigger size of photobioreactor can be more efficient in the view of mass production.