Lignocellulosic materials polysaccharides

Native lignocellulosic materials are heterogeneous, containing cellulose, hemicellulose, hgnin, ash, protein, and a wide array of minor extractives. Cellulose is a linear high molecular weight polysaccharide composed of two residues (P-... 

Lignocellulosics are the most abundant renewable resource in the world, and bioconversion of lignocellulosics into fiiel ethanol could contribute to renewable energy supplies. Hemicelluloses, the second most abundant polysaccharides in nature, represents about 20-30% of agricultural residues [1], The utilization of hemicellulose is essential for whole components utilization of lignocellulosic materials, as well as for the economy of the bioconversion process in industrial applications. 

The fraction consisting of cellulose and hemicellulose or, in other words, the set of all carbohydrates in a lignocellulosic material, is also called holocellulose. Thus, holocellulose is the product obtained after selective removal of lignin, with very low residual-lignin content, minimal loss of polysaccharide, and minimal oxidative and hydrolytic degradation of cellulose. The a-cellulose is the part of material that is insoluble in strong NaOH (17.5%) and may also be designated by crystalline cellulose [5]. In this work, the values of holocellulose and a-cellulose are also shown in Table 1. 

Carbohydrates would be the predominant raw materials for future biorefineries. The major polysaccharides found in nature are cellulose, hemicellulose and starch (see Chapter 1). These molecules would be mainly utilised after they are broken down to their respective monomers via enzymatic hydrolysis, thermochemical degradation or a combination of these two. Cellulose and hemicellulose, together with lignin, constitute the main structural components of biomass. Starch is the major constituent of cereal crops. This section would focus on the potential utilisation of carbohydrates and lignocellulosic biomass for chemical production. 

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