Influence of light stratification on the growth of Scenedesmus quadricauda

• Published in: Biochemical engineering journal 2019-08, Vol.148, p.97-107
• Main Authors: Leonardi, Rodrigo Jorge, Ibañez, Manuel Vicente, Morelli, Matías Nicolás, Irazoqui, Horacio Antonio, Heinrich, Josué Miguel
• Format: Article
• Language: English
• Subjects: LEDs; Microalgae; Photobioreactor; Radiative energy transfer; Simulation of the radiant field; Stratification
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2019.04.022

•The effect of different degrees of stratification were analyzed.•Levels were achieved by changing biomass and position of LEDs on wall.•Simulation of growth with different radiation profiles was successfully performed.•An increase of biomass reduce both the specific growth rate and photosynthetic yield.•An increase of biomass could have positive or negative effect on the productivity. Light availability and light stratification within any photobioreactor and their impact on the growth of microalgae are important issues in the analysis, modeling and design of a photobioreactor. In this work, the microalga Scenedesmus quadricauda was grown in a laboratory scale photobioreactor irradiated with different arrangements of white LEDs giving rise to different degrees of light stratification within the culture medium. To ensure that the observed effects were solely caused by the inhomogeneity of the radiation field properties, the different arrangements of LEDs were required that they emit the same total number of photons per unit time and per unit volume of culture. Assessment of light availability in the culture medium was made using the volumetric average rate of photon absorption and the distribution function of volumetric photons absorption rates. The results obtained highlight the importance of systematically quantifying the degree of stratification of light in the culture medium for the purpose of optimization and scaling up of photobioreactors.