Lignin is formed by the irreversible removal of water from sugars, creating aromatic compounds. Lignin polymers are cross-connected structures with a molecular weights on the order of 10,000 amu.
Lignin is the most abundant organic material on earth after cellulose. The strength of wood is a result of lignin, which makes up about one-quarter to one-third of the mass of dry wood. Lignin is removed from wood pulp before it is turned into paper, and the extracted lignin is used as a binder in particleboard, adhesive for linoleum, and raw material for processing into chemicals (such as DMSO and vanillin). The type of lignin (such as lignosulfonates and kraft lignins) used in industry depends upon the method that was used to extract it.