CO2 Transport and photosynthetic productivity of a continuous culture of algae

The photosynthetic activity of a continuous culture of the microalga Chlorella vulgaris as it is influenced by the CO₂ concentration in the aerating air at different light levels is discussed. It is shown that the characteristic of this behavior is mainly determined by the CO₂ transport from the air to the algal cell. Therefore the critical CO₂ concentration necessary for optimal growth of a particular alga cannot be given in general, as it differs over a very wide range depending on the dispersion system used in the culture vessel. By analyzing experimental data by means of a mathematical model the overall transport coefficient in a well stirred system for the CO₂ transport from the air bubble to the algal cell and the “actual” CO₂ kinetics, can be calculated within reasonable limits of accuracy.