In the marine environment, numerous organisms participate in the biogeochemical cycle of halogens by emitting halogenated volatile organic compounds. However, the enzymatic mechanisms involved in the biosynthesis, uptake and storage of those particular compounds are often poorly known, especially in marine bacteria. The annotation of the genome of Zobellia galactanivorans, a marine flavobacterium living on the surface of macroalgae, allowed to identify several genes potentially involved in this halogen-related metabolism. During this PhD project, I have performed biochemical and structural analyses, and developed functional approaches on genes, coding for vanadium-dependent iodoperoxidases (VIPO) and for a haloacid dehalogenase (HAD). I have determined the specific substrates of the ZgHAD enzyme and analyzed its enzymatic stability, and steady-state parameters. The gene knockout approach revealed that the expression of had gene could provide a selective advantage to this bacterium in the presence of BAA and IAA, haloacids potentially toxic and present in the marine environment. I have also solved the 3D structure of ZgHAD. Through biochemical analyses, I have characterized the third VIPO, specific to iodide oxidation, in Z. galactanivorans (Zg-VIPO3). Thanks to the obtention of a zg-vipo1 gene knockout mutant, I have shown the direct involvement of this gene in iodine uptake in the bacteria, localized by immunolabelling the VIPO activities in membrane fractions and identified, through LC-MS/MS analyses, another potential actor, a membrane OmpA-like protein. The results of this work provide a better understanding of the biological roles of these enzymes and allow to propose a hypothetical model of the halogen metabolism of Z. galactanivorans, in a context of the interactions of this marine bacterium with its environment.