Discovery of enzymes for the control of the biotechnological properties of sulfated fucans – Breaking_Alg

Brown algae are the dominant primary producers in temperate and polar coastal ecosystems. These photosynthetic eukaryotes thus represent a huge marine biomass which is mostly constituted by complex polysaccharides differing from plant polysaccharides. The three main categories of polysaccharides are laminarins, alginates and fucose-containing sulfated polysaccharides (FCSPs). These latter are divided into sulfated fucans (homopolymers of L-fucose displaying numerous substitutions) and fucoidans (heteropolymers containing sulfated L-fucoses mostly as side chains). In contrast to alginates and laminarins, FCSP are not yet significantly exploited, despite very promising biological properties (e.g. immunomodulatory, antioxidant, anti-infectious activities, etc.). Several hindrances preclude serious biotechnological applications of brown algal FCSPs: (i) in literature, the FCSP extracts with biological properties are most of the time very heterogeneous and barely structurally characterized. This strongly limits the study of the structure/function relationships of FCSPs and almost precludes the industrial exploitation of these algal compounds. (ii) Enzymes specific for the hydrolysis and modification of FCSPs are lacking, whereas they are necessary for the structural characterization of FCSPs, the preparation of reproducible oligosaccharides with a controlled structure and maximizing brown algal biorefinery approaches.
The project Breaking Alg aims to knock down these barriers:
• by providing basic knowledge on the bacterial catabolism of sulfated fucans and on the fine structure of these complex polysaccharides from brown algae.
• by setting up standard protocols (compatible with the constraints of food industries) for the extraction of sulfated fucans, the enzymatic hydrolysis of these polysaccharides and the purification of oligo-fucans of defined structures. A library of oligo-fucans will be constituted at the pre-pilot scale and screened for biological properties on human cells (viability, anti-oxidant and immunomodulating activities) in order to provide a proof-of-concept on the structure/function relationships of sulfated fucans.