China 
Africa 
Explore chapters and articles related to this topic
Cellulosic Nanofibers: A Renewable Nanomaterial for Polymer Nanocomposites
Published in Mangala Joshi, Nanotechnology in Textiles, 2020
Mrunalini K. Gaydhane, Chandra S. Sharma
On the basis of the arrangement or order of cellulose chains, the cell wall is distinguished into two layers, the primary cell wall and the secondary cell wall (Fig 15.1a) [16, 17]. The primary cell wall has less ordered cellulose chains and consists of cellulose microfibrils (9%–25%), hemicellulose (25%–50%), and pectins (10%–35%) [14]. The secondary cell wall, obtained from the primary cell wall, is characterized by highly ordered and condensed cellulose microfibrils aligned parallel to the fiber axis [17]. The secondary cell wall is composed of cellulose (40%–80%), hemicellulose (10%–40%), and lignin (5%–25%) [14]. The diameter of the cellulose nanofiber varies from 5 to 50 nm and it is several micrometers long [18].
Structure and Biosynthesis of Lignin
Published in Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel, Hemicelluloses and Lignin in Biorefineries, 2017
Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel
The secondary cell walls of woody tissues and grasses are composed predominantly of cellulose, lignin, and hemicelluloses.16 Lignin is closely mixed with the other wall components. The covalent linkages between lignin and polysaccharides (predominantly hemicelluloses) form lignin–carbohydrate complexes (LCC).17,18 Important LCCs involve quinone methide (QM) and phenolic acids.
Chemical Composition of Biomass
Published in Jean-Luc Wertz, Philippe Mengal, Serge Perez, Biomass in the Bioeconomy, 2023
Jean-Luc Wertz, Philippe Mengal, Serge Perez
Lignified secondary walls are only present in vascular plants, including seedless vascular plants, gymnosperms, and angiosperms, but not in bryophytes. Secondary cell walls are primarily composed of cellulose, hemicelluloses (xylan and glucomannan), and lignin (Figure 5.3), with a minor amount of structural proteins and enzymes.4
Effect of pretreatment with organic solvent on enzymatic digestibility of cauliflower wastes
Published in Preparative Biochemistry and Biotechnology, 2019
Sayari Majumdar, Bhaswati Goswami, Ankita Chakraborty, D. K. Bhattacharyya, Jayati Bhowal
The structural framework of waste biomass is composed of polysaccharides – cellulose, hemicellulose, and lignin – which are collectively termed as lignocellulose. Plant cell matrix is composed of crystalline and non-crystalline heteropolysaccharides. Cellulose is a linear polymer chain linked with β-1, 4-D-glucopyranose monomer units that result in the crystalline nature of cellulose. Hemicellulose is composed of non-pectic and non-crystalline structures. Cellulose and hemicellulose are embedded within the lignin network, which remains distributed in the secondary cell wall of plant tissue. Release of fermentable sugars from lignocellulosic biomass is greatly restricted by the recalcitrant nature of cell wall structure. One of the most important factors of biomass recalcitrance is lignin, which is covalently bound to hemicellulose to form the lignin-carbohydrate complex (LCC).[9,10] In addition, lignin also adsorbs cellulase irreversibly limiting cellulase availability for enzymatic hydrolysis.[10] Cellulose contains both amorphous and crystalline structure. Due to the presence of hydrogen bonding, cellulose chains are present in high order in the crystalline region. Thus amorphous cellulose is much less recalcitrant to bioconversion using enzymatic hydrolysis. Thus deconstruction of the crystalline structure of cellulose and destruction of lignin-carbohydrate bonds has been found to greatly accelerate the enzymatic hydrolysis of cellulose.[11]