Control of the Intensity of Light in a Photobioreactor for Cultivation of Microalgae

Microalgae are microorganism used for the industrial production of high value compounds. These can be cultivated in closed systems called photobioreactors. In PBR is possible to control the conditions of the culture, with the purpose of increasing the production of biomass or metabolites. The relation between the conditions of growth with the light intensity is essential for the increase of biomass. This paper describes the application of a Proportional-Integral-Derivative controller to control the light intensity within the broth in a batch culture of the Acutodesmus obliquus (Scenedesmus obliquus UTEX 393). The performance of the PID controller was tested with laboratory-level experiments using violet light. In the experiments, conventional lighting operation was compared with constant lighting inside the broth. The experimental results showed an increase in the percentage of lipid production compared to cultures where the intensity of light was not constant (conventional lighting).