Analysis of Lignin Using Qualitative and Quantitative Methods

Lignin, the second richest biopolymer on earth, after cellulose and the primary deposition on the secondary cell wall structure of plants is composed of complex phenolic compounds. Its composition makes it an important natural renewable raw material for production of a number of commodity products. Lignin is also commercially produced as kraft lignin during paper manufacturing. Naturally occurring lignin plays significant biological role affecting plant growth, development, stress tolerance and adaptation. Keeping in view their commercial significance and biological role, much research has been directed towards determining the biosynthetic pathways of lignin and its qualitative and quantitative analysis. The present chapter discusses the structural features of lignin, the associated condensation and biosynthetic steps for lignin accumulation in plants, its biological functions and commercial significance. Additionally, the qualitative analysis techniques such as staining and microscopy along with the qualitative methods of both soluble and insoluble lignin determination, such as spectroscopy, have also been discussed. In the end, future scope of development in lignin application and associated challenges has also been deliberated.