Kinetics modeling of docosahexaenoic acid (DHA) production by different strain of microalgae in batch fermentation system

Abstract

This study investigates the fermentation kinetics of different microalgae species for DHA production in a batch fermentation system. The mathematical model was derived from the mass balance of micro-algal cell growth, substrate use, and DHA production with a combination of biological reactions involved in the batch fermentation system. For microalgae cell growth, a logistic model was used and integrated into the mass balance equation. In addition, substrate utilization and DHA production were derived using the Luedeking-Piret-Like and Luedeking-Piret equation. Lastly, the differential equations of the derived dynamic model were integrated into a nonlinear form to simulate and estimate the model parameters. The proposed model was compared with different studies and the model simulation fitted well with all experimental data with R2 values of more than 0.90. Overall, the results revealed that the proposed kinetic models could describe the fermentation characteristic of DHA production, which follows mixed growth associated profile. This model can therefore be used to optimize processes and increase DHA output.