Polychromatic controller of photosynthetically active radiation applied to microalgae

The use of microalgae in biotechnology is on the rise, as they have some advantages over other microorganisms, such as the use of light and carbon dioxide as substrates for their growth, returning oxygen and naturally synthesizing antioxidants, proteins, carbohydrates, carotenoids, among other products. However, the cultivation of microalgae still faces serious productivity limitations and metabolic directions due to light, or the photosynthetic active radiation (PAR). This study addresses the development of an automatic PAR controller based on Fuzzy logic, also contemplating an unprecedented functionality, the possibility of choosing the wavelength that will be emitted. Fuzzy logic easily allows new variables to be added to the controller. Our premise is the search for a control system that is robust for the current process and that at the same time is flexible to absorb new guidelines related to industry 4.0. The present study compared cultures without using the controller against cultures that used the PAR controller. Controlled cultures had higher biomass productivity compared to uncontrolled ~ 200%. Changing the wavelength from white to blue in fixed emitted PAR cultures showed an increase of 173% in protein production and activating the controller, an additional 23% increase was obtained. In addition, the PAR controller reduced energy consumption by three times.