What is cellulose?

Cellulose is an organic compound with the formula (C6H10O5)n. It is a polysaccharide. Cellulose plays an important role in the structural component of the primary cell wall of green plants. There are many forms of algae and the oomycetes.
Cellulose is the most abundant organic polymer on Earth.
It is mainly used to produce paperboard and paper. Conversion of cellulose from energy crops into biofuels such as cellulosic ethanol is under investigation as an alternative fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton.
Some animals, like ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In humans, cellulose acts as a hydrophilic bulking agent for feces and is often referred to as a "dietary fiber".
Structure and properties of cellulose
Cellulose has no taste, is odorless, is hydrophilic with the contact angle of 20–30, is insoluble in water and most organic solvents,and is biodegradable. It can be broken down chemically into its glucose units by treating it with concentrated acids at high temperature.
Cellulose is derived from D-glucose units, which condense through β(1→4)-glycosidic bonds. This linkage motif contrasts with that for α(1→4)-glycosidic bonds present in starch, glycogen, and other carbohydrates. Cellulose is a straight chain polymer. The multiple hydroxyl groups on the glucose from one chain form hydrogen bonds with oxygen atoms on the same or on a neighbor chain, holding the chains firmly together and forming microfibrils with high tensile strength.
Cellulose is a crystalline compound. It requires a temperature of approximately 320 °C and a pressure of 25 MPa to become amorphous in water.
Several different crystalline structures of cellulose are known, corresponding to the location of hydrogen bonds between strands. Natural cellulose is cellulose I, with structures Iα and Iβ. Cellulose produced by bacteria and algae is enriched in Iα while cellulose of higher plants consists mainly of Iβ. Cellulose in regenerated cellulose fibers is cellulose II. The conversion of cellulose I to cellulose II is irreversible. With various chemical treatments it is possible to produce the structures cellulose III and cellulose IV.
Cellulose consists of crystalline and amorphous regions. By treating it with strong acid, the amorphous parts can be broken up, ended up producing nanocrystalline cellulose.