Modeling Approach to Capture the Effect of High Frequency Flashing Light in Steady-State Microalgae Cultures

With the advent of efficient artificial light systems, the possibility of exploiting pulsed light (PL) in microalgal cultivation is gaining renewed attention. In this work, a model was developed to describeArthrospira maxima production in continuous cultivation systems, under both continuous and high-frequency pulsed light regimes. The model is based on the one originally developed by Camacho-Rubio, modified to link photosynthetic units activation to biomass growth, accounting also for maintenance. The modified model, calibrated in continuous light regime, was found to properly predict steady-state microalgal growth at different light intensities and residence times. The model was then validated on experimental data carried out under extreme PL conditions (high frequencies up to 3700 Hz and duty cycles as low as 0.01). Remarkably, it was able to account for the flashing light effect (FLE, i.e., increased biomass production with respect to continuous light supply) measured under such conditions and can therefore be a valuable tool to optimize the energetic efficiency of algal cultivation.