Treasure Hunting in the Genome of the Marine Bacterium Zobellia galactanivorans: Discovery of Novel Enzymes for the Bioconversion of Algal Polysaccharides

摘要: Seaweeds dominate the primary production of coastal environments. This large biomass is mainly constituted by polysaccharides, but these polymers essentially differ from land plant polysaccharides. To develop novel, high-value products from algal biomass, there is an urgent need for specific enzymes modifying the structure and thus the biological and/or physicochemical properties of these polysaccharides. Our group is developing Zobellia galactanivorans as a model marine bacterium for studying the bioconversion of algal polysaccharides. Using this model organism and a combination of genomics, biochemical and crystallographic approaches, we have recently discovered and characterized novel enzymes involved in the assimilation of polysaccharides from brown and red algae (laminarin, alginate, agars). Fascinatingly, these genes of marine origin were also transferred to intestinal bacteria isolated from Japanese and Spanish individuals, due to the traditional consumption of seafood. Thus we have unraveled the possibility of horizontal gene transfers between environmental bacteria associated to food and human microbiota.