CHAPTER 1
INTRODUCTION
1.1 Lignocellulose
Lignocellulose is the major component of biomass that has been generated through various agricultural practices, forest and industry (Anwar, Gulfraz and Irshad, 2014; Collard and Blin, 2014). It can be used as primary or secondary energy source to produce biofuel (Zeller and Grass, 2007). Table 1.1 illustrates the various sources of lignocellulosic biomass from the several sector with some examples. Lignocellulosic materials consist mainly of three polymers which are cellulose, hemicellulose and lignin along with the smaller amounts of pectin, extractives and ash (Collard and Blin, 2014; Bajpai, 2016). The composition of these constituents differ from one plant species to another with age, stage of growth and other conditions (Clark & Deswarte, F., 2015). According to Bajpai (2016), hardwoods for example have greater amounts of cellulose, whereas wheat straw and grasses have more hemicellulose (Table 1.2). McKendry (2002) remarks that the relative proportions of cellulose and lignin is one of the determining factors in identifying the suitability of plant species for subsequent processing as energy crops.
Table 1.1: Various sources of lignocellulose biomass
Supply sector Type Examples
Agriculture Lignocellulosic energy crops
Crops residue
Oil, sugar and starch …show more content…
Hemicellulose contains different hexoses and pentoses (glucose, mannose, xylose, etc.). Since these heteropolysaccharides are often branched polymers, they cannot constitute crystalline structures. Nevertheless, their function in the constitution of natural fibres is important. Together with lignin, they comprise the bonding matrix of the cellulose microfibers. Hemicellulose are found to vary in composition. In agricultural biomass like straw and grasses, hemicellulose are composed mainly of xylan while softwood hemicellulose contain mainly glucomann (Bajpai,
INTRODUCTION
1.1 Lignocellulose
Lignocellulose is the major component of biomass that has been generated through various agricultural practices, forest and industry (Anwar, Gulfraz and Irshad, 2014; Collard and Blin, 2014). It can be used as primary or secondary energy source to produce biofuel (Zeller and Grass, 2007). Table 1.1 illustrates the various sources of lignocellulosic biomass from the several sector with some examples. Lignocellulosic materials consist mainly of three polymers which are cellulose, hemicellulose and lignin along with the smaller amounts of pectin, extractives and ash (Collard and Blin, 2014; Bajpai, 2016). The composition of these constituents differ from one plant species to another with age, stage of growth and other conditions (Clark & Deswarte, F., 2015). According to Bajpai (2016), hardwoods for example have greater amounts of cellulose, whereas wheat straw and grasses have more hemicellulose (Table 1.2). McKendry (2002) remarks that the relative proportions of cellulose and lignin is one of the determining factors in identifying the suitability of plant species for subsequent processing as energy crops.
Table 1.1: Various sources of lignocellulose biomass
Supply sector Type Examples
Agriculture Lignocellulosic energy crops
Crops residue
Oil, sugar and starch …show more content…
Hemicellulose contains different hexoses and pentoses (glucose, mannose, xylose, etc.). Since these heteropolysaccharides are often branched polymers, they cannot constitute crystalline structures. Nevertheless, their function in the constitution of natural fibres is important. Together with lignin, they comprise the bonding matrix of the cellulose microfibers. Hemicellulose are found to vary in composition. In agricultural biomass like straw and grasses, hemicellulose are composed mainly of xylan while softwood hemicellulose contain mainly glucomann (Bajpai,