1 – Photobioreactors for the production of microalgae

Microalgae have been proposed as valuable microorganisms for several applications, from production of pharmaceuticals to wastewater treatment. Whatever the final application, the core of the process is the photobioreactor in which microalgae are produced. To design adequate photobioreactors, it is mandatory to understand the major phenomena limiting the performance of microalgae cells such as light availability, nutrients supply including CO2, environmental conditions including temperature and solar radiation, and mixing. To fulfill the requirements of microalgae cells, different technologies has been proposed such as raceway and thin-layer open reactors, in addition to tubular and flat-plate closed reactors. These technologies are still being upgraded and improved to maximize the biomass production capacity and to reduce the production cost. Additionally, the control and modeling of these reactors is a hot topic for the industrial development of microalgae-based processes. This chapter summarizes the current state of the art on photobioreactor design and operation, discussing the major challenges to be solved to achieve a massive expansion of microalgae-based technologies.