Interaction between light and photosynthetic microorganisms

This chapter aims to introduce the physical concepts and to provide the experimental and theoretical frameworks necessary to understand and to quantify the interaction between light and photosynthetic microorganisms. Indeed, light transfer is arguably the most critical aspect to consider in designing, optimizing, and operating photobioreactors of all sizes for the production of a wide range of value-added products. This chapter presents state-of-the art theoretical and experimental methods for determining the scattering phase function and the absorption and scattering cross-sections of unicellular and multicellular microorganisms as well as of colonies. An extensive database of these so-called radiation characteristics over the photosynthetically active radiation region is presented for a wide variety of promising freshwater and marine microalgae, cyanobacteria, and nonsulfur purple bacteria with various shapes, sizes, pigments, and responses to stresses. The effects of photoacclimation and of progressive and sudden nitrogen starvation on the radiation characteristics are illustrated with Nannochloropsis oculata. Finally, limitations of current approaches are discussed and future research directions are suggested. © 2016 Elsevier Inc.