Day/night cycles in lipid accumulating microalgae

Microalgae are an interesting source of lipids for the production of biodiesel but the current production process needs to be optimized in order to become economically feasible. High annual productivities can only be achieved if solar light is efficiently used throughout the day. However, daily irradiance is highly variable and microalgae need to adapt constantly to the changing conditions. Therefore, maintaining optimal conditions for microalgae production outdoors is challenging.


Work with Neochloris oleoabundans, a promising lipid producing species, shows synchronized cycles in O2 evolution and cell division, even under constant light conditions in a continuously operated photobioreactor. Different light and stress conditions yield different growth rates, however, duration of the cell cycle remains 24h. This suggests a circadian rhythm in the cell division cycle in Neochloris oleoabundans. Due to this synchronized cell cycle, the biochemical composition of the cells (lipids, starch, proteins and chlorophyll content) in the photobioreactor changes throughout the day. So, in order to determine the best moment for harvesting cells with a high lipid content, knowledge about the circadian behaviour of the cell cycle is important.



The aim of this research is to obtain more knowledge in the circadian behaviour of the cell cycle of lipid producing microalgae grown in photobioreactors. This will provide ways to optimize the current production process under outdoor day/night cycles.


Neochloris oleoabundans is grown in a lab-scale photobioreactor under simulated outdoor conditions. The circadian rhythm of the cell cycle is analysed using flow cytometry. In addition, cell composition (lipids, starch, proteins) during the cell cycle is investigated.

Thesis projects

Within this project there are various possibilities for doing a BSc or MSc thesis. If you are interested in doing a BSc or MSc thesis, feel free to contact me.