Design of Photobioreactors for Algal Cultivation

The cultivation of phototrophic microalgae has been recognized as a promising platform for the production of renewable biofuels and a variety of valuable products through a series of biorefinery processes. To enable microalgal growth at the maximum productivity level to enhance economic competitiveness, the design of photobioreactors for efficient and cost-effective phototrophic cultivation is one of the most important issues in practice. This article elucidates comprehensive information on the characteristics of microalgae cultivation as well as the key factors and challenges that should be addressed regarding the phototrophic process. The design principle of the photobioreactor (PBR) for achieving highly efficient cultivation is also summarized. Many of today's PBRs are open systems due to the cost issue; even so, closed photobioreactors have recently attracted considerable attention for the production of valuable compounds. The comparison of designs and features of the open and closed systems are discussed. Furthermore, the current development status of commercial microalgae cultivation systems by several companies is given as examples to expose the potential of and the challenges in using microalgal biomass. The objective of this chapter is to provide useful knowledge and information with regard to the design of PBR for microalgae cultivation with critical evaluations of those systems to facilitate the future development of the microalgae industry.