Structural changes of lignin in the jute fiber treated by laccase and mediator system

• The lignins in jute fiber were degraded during LMS treatment.
• The content of phenolic hydroxyl and methoxy of residual lignins decreased after LMS treatment.
• The content of carboxyl of residual lignins increased after LMS treatment.

To study the structural changes of lignin in the jute fiber treated with laccase and mediator system (LMS), lignins from the control and LMS-treated jute fiber were isolated and characterized by gel permeation chromatography (GPC), elemental analysis, measurement of phenolic hydroxyl group content, FTIR and 1H NMR. The results showed that the molecular weights of the lignin from LMS-treated jute fiber were lower than those of the lignin from the control jute fiber. The contents of phenolic hydroxyl group, aliphatic hydroxyl group and methoxy group of the lignin from LMS-treated jute fiber decreased, while the content of carboxyl group increased.