Optimal Harvesting of Lipids-Rich Microalgae Subject to a Circadian Cycle Under Limited Nitrogen Supply

The harvesting of algae rich in triacylglycerol from an open raceway pond with volume-changes synchronized to the circadian cycle and under limited nitrogen supply is researched. A reduced metabolic model of its non-balanced growth is embedded into a macroscopic balance for simulating growth in such a type of bioreactor. Afterwards, the model is used jointly with optimal control to derive cyclic inlet and outlet flow policies as well as optimal nitrogen levels for different time-horizons and initial physiological states in a case study which uses bibliographic data for the Tisochrysis lutea alga.