Lignin is one of the main components of trees or plants, jointly with the cellulose and the hemicellulose. Constituting around 30% of the dry mass of wood, lignin give trees their rigidity but also makes them water resistant and degradation resistant. It is fibrous and tasteless and was discovered by a Swiss botanist Augustin Pyramus de Candolle in 1813.
In the current industrial processes, lignin is a by-product of the paper industry which is mainly interested in extracting the cellulose from the wood. Lignin is responsible for the yellowing of the paper after exposure to the sun. Therefore, chlorinated products are used for the extraction of lignin from paper pulps, which are difficult to treat as harmful for the environment. In addition, lignin can also give paper a certain flavour of vanilla.
At the end of the paper production process, large amounts of lignin are left over and most of it is currently burned for heat production or used in other industrial applications such as agriculture or construction.
Chemically, lignin is a polymer and has a structure allowing replace petro-sourced applications such as fenol. Its main advantage is that it is much more sustainable than petro-sourced products as the tree production removes CO2 from the atmosphere rather than emiting. It is naturally abundant, very energy dense, and since 2010, its scientifc interest has significantly increased.
The current challenge is to break lignin down into simple molecules as raw material to produce many interesting high-value chemical such as antioxidants, phenol, precursors for polyamide and polyester and much more. The global market potential for lignin is estimated at more than $240 billion.