The invention relates to a gene encoding a polypeptide exhibiting an endofucanase activity, i.e. an enzyme which degrades fucanes or fucoidans embodied in the form of polysaccharides formed by sulphated fucose units. A method for producing said polypeptide in the recombinant form by carrying out genetic engineering techniques using said gene is also disclosed. Said invention also relates to the use of the recombinant polypeptide for degrading fucoidan-type polysaccharides, thereby making it possible to obtain oligosaccharide fractions, in particular tetrasaccharide and hexasaccharide fractions.
