An evaluation of light wavelengths, intensity and control for the production of microalgae in photobioreactors: a review

Microalgae production has been vastly exploited in the last decade by scientific institutions and private organizations. It is not only one of the most efficient photosynthetic organisms, but also requires reduced cultivation space when grown in photobioreactors, compared to crops. Light is one of the most important variables that can limit photosynthetic microalgae growth and biomass production. The objective of this text is to bring an overview on how light influences microalgae growth inside photobioreactors and to delineate the current state and progress of the latest research on the topic of light intensity and wavelength, and light control in microalgae production systems. We show that, despite the extensive number of studies focused on the effects of light wavelengths and intensity on the production of microalgae, very few of those were dedicated to explore and evaluate the control of light variables in photobioreactors, especially in an automated approach, making it an interesting topic to be further investigated and developed. Finally, this review contributes to the understanding of several aspects of algae growth that can be related with the light environment inside photobioreactors. (AU)