Optimal harvesting of lipids-rich microalgae subject to a circadian cycle under limited nitrogen supply

Abstract

The harvesting of algae rich in triacylglycerol from an open raceway pond with volume-changes synchro-nized to the circadian cycle and under limited nitro-gen supply is researched. A reduced metabolic model of its non-balanced growth is embedded into a macro-scopic 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.