Algal cell walls are a type of extracellular matrix mainly made of polysaccharides, highly diverse, complex and heterogeneous. They possess unique and original polymers in their composition including several polysaccharides with industrial relevance such as agar, agarose, carrageenans (red algae) alginates and sulphated fucans (brown algae). Part of this work studied the polysaccharide composition of macroalgal cell walls, with special focus into the brown algal cell walls in a context of evolution, wall architecture and embryo development. Thus, we found evidence of the presence of (1-3),(1-4)--glucan, also known as mixed linkage glucan, probably present in brown algae through a convergent evolutionary process which provides another piece of the cell wall puzzle. We also demonstrated the presence of chimeric-arabinogalactan proteins (AGP) in brown algal cell wall and confirmed their role in cell development.
Another part of this work focused in the development of a novel methodology for the discovery of unknown algal polysaccharides and characterization of carbohydrate binding proteins. Based on the coevolution between alga and marine saprophytic microorganisms, which use the algal decaying tissue as a nutrient source. We successfully optimized the method and characterized four new carbohydrate-recognizing proteins (two carrageenan binders, one arabynoxylan binder and one xyloglucan binder), which may be used as analytical probes for polysaccharide research. Finally, we also wanted to concept proof that is possible to use the Comprehensive Microarray Polymer Profiling (CoMPP) as a tool for other extracellular matrixes such as marine animals and not only for algal or plant cell walls. Thus, we discovered fucoidan and cellulose epitopes in several tissues of various marine animals from different phyla.