Étude de stratégies de culture de Dunaliella tertiolecta combinant haute densité cellulaire et accumulation de lipides en vue de produire du biodiesel/Study of culture strategies of Dunaliella tertiolecta combining high cell density and accumulation of lipids to produce biodiesel

Microalgae are photosynthetic organisms using light to capture CO2. Some species can accumulate, under specific growth conditions, carbon as lipids (triglycerides). This characteristic led the scientists to think about cultivating this microorganism to produce biodiesel. The following study is based on the cultivation of a 5 to 10 µm length green biflagellate microalgae, Dunaliella tertiolecta. Two objectives will be presented in parallel: first, the growth rate and then the oil content. An optimal design of experiment has been used to determine the influence of the concentration of different components in the medium as sodium chloride, nitrate and phosphate on the two responses. The fluorescence technique allows measurements of oil level within the microalgae. The experimental results show that increasing the growth leads to an oil level reduction. The sudden depletion (stress) of an essential nutrient stops the growth but increase the lipids' storage. A nitrate stress allows lipid dry mass percentage of around 19%. [PUBLICATION ABSTRACT]