The effect of CH4and CO2on N. gaditana growth was evaluated exposing the microalgae culture to atmospheres containing different compositions of these gases, in batch photobioreactors. On a second phase, CO2 absorption was evaluated in a continuous photobioreactor providing direct contact of the gas with the culture, in a single stage process. Finally, a two stages process was evaluated, providing gas/liquid contact in an external unit for mass transfer, which was connected with the photobioreactor by a continuous circulation flow.