Cellulose constitutes the most abundant and renewable polymer resource available worldwide. It is estimated that by photosynthesis, 1011–1012 tons of cellulose are synthesised annually in a relatively pure form, for example, in the seed hairs of the cotton plant, but more often are combined with lignin and other polysaccharides (so-called hemicelluloses) in the cell wall of woody plants (Klemm et al., 2002). Cellulose has been used in the form of wood and cotton for thousands of years as an energy source, a building material and for clothing.