This paper shows a model of a photobioreactor (PBR) combining different phenomena inside a reactor for microalgae culture such as: fluid dynamics, photosynthesis kinetics and mass balances. The proposed model has a new characteristic; it is the inclusion of an empirical equation which takes into account the Light and Dark cycles behavior in a dynamic mathematical model for PBR production prediction. Finally, the model of PBR was simulated with a regulatory PI control strategy, showing adequate results of the system in closed loop.