Valeria Villanova

Optimising diatom growth and yield by mixotrophic growth.

Microalgae are unicellular microorganisms able to use the light as an energy source via photosynthesis like plants. Moreover, microalgae are capable of growing in the dark, via the respiration of a carbon source. Eventually, a few microalgae can combine photosynthesis and respiration for growth, so that both processes are optimised. In my PhD I am studying this process (called mixotrophy) using a model microalgae Phaeodactylum tricornutum and glycerol as carbon source. This carbon source supports the growth of P.tricornutum and leads to the production of high-value products (e.g. lipids), which can be used for bioenergy (e.g. biofuel production). The aim of my project is first to understand the consequences of this molecule on  the respiration and photosynthesis in  P.tricornutum. In addition, I am also trying to identify other molecules that promote mixotrophy with a comparable effect of glycerol using special microplates that allows the simultaneous screening of  ~ 100 possible substrates. This part of the work is done in a research institute in Grenoble. The second part of my thesis will focus on the industrial exploitation of my results for bioenergy applications. This will be done in an industrial biotechnology company (Fermentalg) located in the south west of France (Libourne). Here, I will focus on the optimization of yield and productivity of P.tricornutum, using both light and selected carbon sources, in large scale culture systems (e.g. photobioreactors).