Development of High-Speed and Large-Scale Culture Technology of Marine Algae Using Seawater with High Concentrations of Dissolved Carbon Dioxide

The effective use of marine biomass has recently been identified as a feasible method of renewable energy production. Therefore, to facilitate the effective use of algae biomass, it is essential to develop techniques for the mass production of algal cultures. It is also important to develop artificial culture techniques that are not affected by natural phenomena such as weather. This study utilized a newly developed culture technology that uses seawater with high concentrations of dissolved CO2 (CO2 seawater). The experiments in this study were conducted to test the effects of CO2 seawater on algal growth. In addition to experimental conditions that were previously investigated in industrial algae farming scenarios, it is also necessary to consider the effects of new parameters associated with increased CO2 concentrations. The following four conditions were experimentally investigated: (1) the tolerance of algae to changes in pH, (2) the effect of CO2 seawater on long-term culture growth, (3) the effect of continuous culture experiments, and (4) the effect of water flow rate on cultured algae. The results in terms of having excelled especially indicate that a 1-month long-term algae culture period in seawater with CO2 concentration of 1.0% led to growth that was approximately 4.5 times faster than growth in seawater without the CO2 additive. Furthermore, the results also provided useful information regarding the proper flow rate needed to enhance algal growth.