What is Lignin?

Mary McMahon
Mary McMahon

Lignin is a complex organic polymer found in the tissues of plants. It plays a number of important roles in plant biology, and it also has an assortment of industrial applications, making it a coveted product among certain manufacturers. In nature, lignin is created by plants, and when they are processed for various industrial purposes, it is possible to extract the lignin for an assortment of uses.

Most lignin used in manufacturing is extracted from timber.
Most lignin used in manufacturing is extracted from timber.

This chemical compound is found in the cell walls of plants. It binds with cellulose, another plant fiber with many uses, to make sturdy, the cell walls strong. The more lignin a plant has, the woodier it becomes; it provides the shape and form of stalks, twigs, and tree trunks. In addition to providing support and structure, the polymer also helps its parent plant conduct water, and it sequesters carbon in the plant. After a plant dies, the lignin takes more time to break down than the rest of the plant, slowly releasing carbon back into the natural environment.

For humans, wood with a lot of lignin has been recognized as useful for centuries. The more a wood has, the sturdier and stronger it will be, making it suitable for more tasks. Lignin also burns very efficiently, which makes heavily lignified woods like oak popular as fuel, as well. The substance was named in 1819, after the Latin lignum, which means “wood,” referencing its important role in the structure and development of wood.

When extracted from timber and plant products, lignin can be included in a wide variety of things. It can be used as an emulsifying, sequestering, binding, or dispersal agent, depending on how it is processed and what it is used with, appearing in everything from paints to treatments for roadways. Many paper mills and lumber processing facilities view lignin as a valuable byproduct of their industrial processes, extracting and selling it to other industries.

Chances are very high that any person has a product which contains lignin in his or her vicinity, aside from the obvious furnishings and construction materials. It appears in a wide variety of chemicals from synthetic flavorings to textile dyes, and it can also be found in a wide variety of industrial materials. People also consume lignin every day, in the cells walls of the fruits and vegetables included in their diet. Most that is used in manufacturing is extracted from timber, often in paper mills, where wood is shredded, pulped, and treated to produce paper, extracting the lignin it contains in the process.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


I am Ali from Finland. At the moment I have started working on a research project in Austria regarding Lignin. Can someone tell me something about the conversion of lignin to fuel, like alkaline.


Deterioration of lignin differs from plant to plant depends upon its composition of structural units. isolated lignins usually starts their degradation around 200 degrees temperature, and melt between 600-700 degrees. But thermal stability is dependent upon plant source and isolation procedure.


Lignin starts to deteriorate at what temperature? At what temperature is it combustible?

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