Two kinds of bioreactors, a bubble-column and an air-lift bioreactor, have been designed. The influence of operating conditions such as medium composition, light intensity, carbon dioxide concentration in the flushing gas, culture temperature, and gas flow rate, on photosynthesis of Dunaliella tertiolecta were studied using a chemometrics approach. The bubble-column bioreactor system was shown to be advantageous over the air-life because of a weaker intensity of hydrodynamic stress derived from gas bubble dispersion and culture broth mixing. Optimal conditions for carbon dioxide fixation or maximal growth rate were determined. The effect of hydrodynamic shear forces on the algal wall produced by gas bubbling was identified as one of the most significant factors for algal growth.