Cellulosic feedstock composition
Cellulosic feedstock is composed of cellulose, hemi-cellulose,
lignin, and solvent extractives. Lignin acts as a cementing material
and binds all other constituents together. It is also responsible for
providing structural rigidity to a cellulosic feedstock. Cellulose is a
polymer of repeating β-D-glucopyranose units and is a chief constituent
of the feedstock. Hemi-cellulose, like cellulose, is a polysaccharide
but is less complex and easily hydrolysable. Soluble materials or
extractives in the feedstock consist of those components that are
soluble in neutral organic solvents. The distribution range of different
constituents in softwood and hardwood is explained in Table 1
(Anonymous, 2008; Miller, 1999). Kuhad and Singh (1993) and Olsson
and Hägerdal (1996) provide more information on constituents of
other cellulosic feedstocks.