Structural features of enzymatic hydrolysis lignin from the corn stalks and furfural residue

Structural features of enzymatic hydrolysis lignin from the corn stalks and furfural residue was compared with lignin extracted from paper-making black liquid (PBL).Lignin was characterized by FT-IR, GPC, 13 C-and 1 H-NMR analysis.Enzymatic hydrolysis lignin from the corn stalks (CS) had a 12.2% higher phenolic hydroxyl content and FR had a 4.74% higher than that of PBL.FR had lower alcoholic droxyl content than that of CS and PBL.The Mw of CS was determined to be 5,520Da, which was 1.5 times of the Mw of PBL (3,660 Da).The Mn of both FR and PBL had similar values of about 4000 Da. the Mn of CS was only 1903 Da.The polydispersity index (Mw/Mn) of CS and FR were calculated to be 1.92 and 1.70, respectively.The lignin of CS and FR consisted of β-O-4units, the C-γ withα-C=O originated from side chain oxidation via hemolytic cleavage and condensation of β-β structures during enzymatic hydrolysis process.