Enzymatic polymerisation and effect of fractionation of dissolved lignin from Eucalyptus globulus Kraft liquor

► The ability of laccase to polymerise Kraft dissolved lignin was evaluated. ► Lignin fractionation was carried out to improve the polymerisation degree. ► A comparison between solvent extraction and acidic fractionation was accomplished. ► S/G ratio of the lignin fractions may play an important role in polymerisation degree. ► An increase of the lignin Mw, with a factor ranging from 4 to 21, was achieved.