Lignin exists in many kinds of higher plants. Comparing with the cellulose
lignin is the secondary abundance of biological polymers in the earth. It is meaningful to use the lignin effectively. However
because of the complexity of lignin structure
it is always an important research project in the long run for people to know the details of its structure
and to find out the appropriate methods to analyze it. This article mainly discussed some progress in the biosynthesis pathways of lignin units and the structure of the lignin
including the chemistry composition
functional groups
the linkages of lignin monomers and the model compounds. Meanwhile it introduced some degradation methods and non-degradation methods of analyzing the lignin.