A Simple Model for Algal Photosynthesis for Better Light Utilization with Flashing Light

Abstract

Photobioreactors (PBRs) demonstrating very high bio-productivity involve a complex interaction between biomass density, light path, light intensity, and timescales of random cell movement. This work presents a new reactor model capable of simulating the effects of the above-mentioned parameters on the biomass productivity of a PBR. The work presented in this paper includes (i) development of photosynthesis model based on occupancy of charge carriers associated with the linear electron transport chain of photosystem-II, (ii) tuning and validation of the kinetics model using flashing light data reported in the literature, and (iii) reactor model development by integrating kinetics with a simple flow depiction including the effect of boundary layer thickness.For the first time, the role of the boundary layer in determining the productivity of PBRs is elucidated.

Identifying Opportunities for Improving the Light Utilization Efficiency of Microalgae in a Flashing Light Regime

“…The kinetic model is then used to study the effect of the flash time on the light utilization efficiency. It must be noted that Mahulkar et al carried out an extensive validation of the model with experimental data. , For the sake of brevity, the discussion on the model validation is not repeated in the present paper. Readers are requested to refer to Mahulkar et al for evaluating the predictive capability of the model.…”

“…In the present work, the model developed by Mahulkar et al is used for exploring the influence of the light intensity, flash time, and light duty cycle values on the light utilization efficiency. The model is based on the sum of the exponentials to simulate the dynamic behavior of PS-II charge carriers.…”

“…Although Zarmi et al 14 proposed a more elaborate four step model for simulating the four stages of photon capture by the PS-II for every cycle of water splitting, it has too many parameters to be fitted from the experimental data. Mahulkar et al 15 presented a simpler twocharge carrier photosynthesis model. The model was able to predict the effect of the frequency of the flashing light on the photosynthetic response of microalgae at wider light duty cycle values with reasonably good accuracy.…”

“…Dynamic photosynthesis models have been proposed in the past for characterizing the effect of light/dark cycles on the photosynthesis rate. − The models proposed by Eilers and Peeters, Rubio et al, and Fernandez-Sevilla et al utilize the concept of a photosynthetic factory (PSF). The above-discussed models − were formulated assuming PSF as a single charge carrier having a single reduction and reoxidation time.…”

“…In the present work, the kinetic model presented by Mahulkar et al 15 is extended to study the dynamics of photosynthesis. The model is first employed for developing a better understanding of the complex interaction between the light intensity, flash time, light duty cycle, and light utilization efficiency.…”