LIGNIN

Lignin is a macromolecule characterised by monolignols, the starting material being phenylalinine. It is common in trees and herbaceous plants, where is part of the cell walls, including the xylem fibres. After cellulose it is the most abundant organic compound, accounting for up to 33% of the dry mass of wood. It fills space between cellulose and pectin, giving rigidity, conducting water and providing defence against pathogens.

Lignin has both a negative and a positive side; it must be removed from plants when processed for paper and textiles, but is in fact on its own a very commercial compound. Studies of its uses began in 1927, when the Marathon Corp. in Rothschild, Wisconsin took an interest in it; since then this firm has been renamed LignoTech USA, and is owned by a Norwegian company, Borregaard.

The commercial uses of lignin and its derivatives include raw materials for use in vanillin, ethanol, humic acid, environmentally friendly dust suppression agents, dispersants in high performance cement applications, textile dyes and agricultural chemicals.

When burned, methoxy phenols are formed, of which guaicol and syringol are responsible for the flavour of smoked foods.

(for related post, see note below on pectin)