Les métaux (Cd, Cu, Pb et Zn) dans la production des microalgues sur différents milieux de culture : biodisponibilité, bioaccumulation et impact physiologique

The quality and the productivity of microalgal cultures depend on different physicochemical factors like salinity, pH, nutrient and trace element (including trace metals) concentration in the culture medium. During this doctoral study, the bioavailability of four metals for microalgae was tested in coastal seawater and several salt groundwaters. The bioavailability of a metal depends on its own total concentration as well as that of ligands in the medium, and on the relative affinity of each ligand towards the given metal. After a comparative study of the quality of algae grown in coastal seawater and salt groundwaters, the complexation capacities of these media were studied to allow a better understanding of the observed variations of metal bioaccumualtion in the produced microalgae. An experimental study with a new artificial medium (DAM) developed during our work allowed to put forward some hypotheses regarding the interspecific variations of metal bioaccumulation.