The dynamics of oil accumulation in Scenedesmus obliquus

Promovendus ir. G (Guido) Breuer
Promotor RH (Rene) Wijffels
Copromotor Packo Lamers DE (Dirk) Martens
Organisatie Wageningen University, Bioprocess Engineering

vr 6 maart 2015 13:30 tot 15:00

Locatie Aula, gebouwnummer 362
Generaal Foulkesweg 1
6703 BG Wageningen


Novel sustainable sources of vegetable oils are highly desired. Microalgae can potentially be a promising source. Microalgae can produce large amounts of these oils, but only do so during nitrogen starvation. Nitrogen starvation, however, also affects many other cellular processes. This thesis provides a quantitative understanding of the microalgal response to nitrogen starvation, and aims to optimize oil production. The differences between microalgae species in their response to nitrogen starvation are characterized, it is quantified how process conditions during nitrogen starvation influence oil production, and it is investigated how starchless mutants can be used to improve oil production. These findings are used to develop a mechanistic model that can describe photosynthesis and carbon partitioning during nitrogen starvation. This model is used to explore how oil production can be optimized. These findings are finally used for an economic and energetic feasibility evaluation of microalgal oil production.


  1. Carbon partitioning between starch and fatty acids in Scenedesmus obliquus is caused by competition for a common carbon pre-cursor. (this thesis)
  2. A high photosynthetic efficiency during nitrogen starvation is more important than high oil contents, when screening for oleaginous microalgae. (this thesis)
  3. Biodiversity is important to inspire the science of the future.
  4. Technological bottlenecks should be solved by biological solutions.
  5. As long as meat replacers are called meat replacers they will never replace meat.
  6. To realize a sustainable economy, a change in habits is just as important as technological progress.