Light irradiance and spectral distribution effects on microalgal bioreactors

Abstract

The irradiance and light spectral distribution affect the growth and productivity of microalgal cultures. In extensive open pond cultures, the light control has limited options, mainly the culture depth. In photobioreactors, besides the culture depth, the light source, configuration of the reactor, light pathway, and flow rate can be used to control the characteristics of the light available to the cultures. The change of light conditions can also be used to modify the composition of the microalgal biomass produced to optimize the production of bioproducts of interest. Additionally, in mixed cultures, the species composition can be influenced by the light quantity and quality. Determining the effect of the light quantity and quality in photosynthetic cultures will help to develop strategies to optimize the production of biomass, lipids, pigments, proteins, and other compounds of interest in photosynthetic microorganisms. Information obtained from bench scale cultures can rarely be applied directly to large‐scale bioreactors. Nonetheless, determining the kinetic parameters of microalgal cultures at bench scale will reduce the time needed to optimize the cultures in photobioreactors. In this work, a review of the main factors is presented, along with specific examples of the effect of light quality and quantity in cultures with single and multiple species. Additionally, some models to predict the effect of light on microalgal productivity are discussed.