Meryem Belfquih

Macroalgae are major primary producers in coastal environments, by fixing carbon in the form of polysaccharides and reinjecting resources transformed by heterotrophic marine bacteria. The marine flavobacterium, Zobellia galactanivorans, has numerous genes dedicated to the utilization of algal polysaccharides, often grouped in genomic units called Polysaccharide Utilization Loci (PUL). Some functions involved in the use of a substrate may therefore be encoded outside the PUL. This also suggests the existence of cross-regulations that allow one substrate to influence the expression of metabolic pathways not directly involved in its utilization. Within this context, my work focuses on the identification and charaterization of cross-regulations involved in the use of alginate and carrageenan, two polysaccharides predominantly and respectively found in brown and red algae, and widely exploited industrially. I’m carrying out this project as part of the X-Reg project. Future results will enhance fundamental knowledge of interactions between bacteria and macroalgae. In biotechnology, the potential discovery of the algal degradation compounds and the control of regulatory cascades could further enable the development of inducible expression systems in flavobacteria and optimize processes for the valorization of algal biomass.