The invention relates to a method for enzyme cleavage of polysaccharides comprising a first sequence [→4)-β-D-GlcpA-(1→4)-α-L-Rhap3 sulphate-(1→]n and a second sequence [→4)-α-L-IdopA-(1→4)-α-L-Rhap3 sulphate-(1→]m, the first and second sequences respectively comprising two monosaccharide units connected by an osidic bond, wherein said method is such that: said polysaccharide sequences are provided; a microorganism capable of producing an enzyme substance of the lyase class is provided; and said enzyme substance is brought into contact with said polysaccharide sequences in such a way as to bring about cleavage of the osidic bond according to a β-elimination reaction. The invention is characterized in that a microorganism belonging to the bacteria of the Ochrobactrum genus is chosen for producing said enzyme substance.