The lignocellulosic biomass is mainly composed of
40e50% cellulose, 25e30% hemicellulose, and 15e20% lignin [2].
Cellulose is a linear polymer of glucose, whereas hemicellulose is
a branched heteropolymer of glucose, xylose, arabinose and
galactose. Lignin is a hydrophobic complex of cross-linked aromatic
polymers. Because cellulose polymers are tightly embedded
in the complex of hemicellulose and lignin, pretreatment should
be conducted to liberate the cellulose polymers from this knotty
complex [3,4]