An outline of photosynthetic microorganism growth inside closed photobioreactor designs

This review deals with the development of outdoor closed photobioreactors and their improved performance achieved between the end of the second and the beginning of the third millennium. The evolution of closed photobioreactors operating outdoors, under intensive conditions, is the main objective of this review. The cultivation of photoautotrophic microorganisms for the production of green products is more desirable in closed systems than open systems, because they allow the best control of culture parameters, optimal growth, high-value products, and reduce the risk of contamination of the culture by undesirable microorganisms. In addition, closed photobioreactors are the best to maximize both volumetric and areal productivities. Culture systems such as tubular, column, and panel photobioreactors are the most effective configurations for future industrial applications among the many outdoor cultivation systems.