Analysis of Carbon Dioxide Solubility Increasement Caused by Baffle Diameter Variation in Airlift Photobioreactor to Growth Rate of Synechococcus HS-9 Biomass

Photobioreactor (PBR) have been one of the most popular system that used for multiplying microalgal biomass. Many researches have been conducted to develop photobioreactor that suit the most with prominent microalgae strains. Carbon dioxide supply is one of many sectors that play an important role for growing microalgae. Carbon dioxide are used by the microalgal cells to produce many chemical compounds that support growth. In many cases, carbon dioxide must be solved into growth media to be utilized by the cells. This research focused on analyzing the effect of carbon dioxide solubility increasement caused by variation of baffle in airlift photobioreactor (APBR) to growth rate of Synechococcus HS-9 biomass. Twenty-one day of experiment resulting that there are growth rate differences occurs. The highest growth rate occurs in APBR-A, APBR-B, and control PBR are 0.515, 0.463, and 0.738 respectively. Despite of the maximum growth rate occurred, there are fluctuation of growth rate happen during experiment. Carbon dioxide solubility test then conducted to see effect of baffle variation. The best carbon dioxide solubility occurred in APBR-B with 23 mg/L, then followed by APBR-A with 22 mg/L, and control PBR with 20 mg/L after 24 hours of treatment. Further analysis resulting that there is no strong correlation between carbon dioxide solubility increasement to growth rate of Synechococcus HS-9 biomass. This occurred due degression of acidity value (pH) caused by excess of carbonic acid formed by carbon dioxides who diluted into growth media.