Measurement of Specific Surface Area and Evaluation of CO₂ Mass Transfer Coefficient on the Cell of Blue-green Algae during Batch Culture

Abstract

CO₂ fixation by a blue green algae, Spirulina platensis, was evaluated using volumetric mass transfer coefficient (K_La). The specific surface area of the cells was measured with an image analyzer, and the specific surface area of the cell was evaluated and statistical distribution of the cell length was analyzed. CO₂ mass transfer coefficient k^CO2_L was evaluated with the specific surface area of the cell (a). The surface area of each cell (a_d) was about 5.0 (m²/g-d.m.), and CO₂ mass transfer coefficient k^CO2_L ranged between 0.8×10^-4 and 1.0×10^-4 (m/day). The value of k^CO2_L during the linear growth phase was found to decrease to one fifth of the maximum. The distribution of the cell's surface area in the late growth phase (14-th day) also correlated well with the Weibull distribution. It was found that the mixing caused cell destruction.