A Brief Introduction of Lignin

Lignin is an alkyl-aromatic polymer, which is a dominant component in plant biomass. However, the inherent structure of lignin depends on the plant species. Hence, it is a key to understand the complex structure of lignin before valorization of it. This introductory chapter briefly discusses the structure of lignin from its building blocks and interlinkages. Besides, the metabolic pathway toward lignin monolignols and bioengineering of lignin were shortly introduced.