Estimation of CO2 stripping/CO2 microalgae consumption ratios in a bubble column photobioreactor using the analysis of the pH profiles. Application to Nannochloropsis oculata microalgae culture.

Nannochloropsis oculata was grown in an outdoor bubble column photobioreactor. To obtain information about the behaviour of microalgae/photobioreactor system related to the CO(2) net balance, an analysis of the pH profiles during microalgae growth was carried out. The use of the carbonate equilibrium chemistry and the overall CO(2) volumetric mass transfer in the photobioreactor has permitted to obtain information of the CO(2) losses/CO(2) microalgae consumption ratios. The simplicity of the technique used (a pH probe) could extend the use of this methodology for the correct selection of the photobioreactor/microalgae parameters with the aim to maximize the [CO(2) uptaken/(CO(2) uptaken+CO(2) stripped)] ratios.