Cell-wall polysaccharides cellulose

The wood cell wall polysaccharides—cellulose and the hemicelluloses—have a strong affinity for water molecules in either their liquid or vapor state. Lignin, on the other hand, is almost water repelling. In fact, within the wood s internal architecture or ultrastructure see later sections) lignin acts to block potential sites for water absorption. 

In 1977, Ohnishi and Kato (2850) described the identification of several carbonyl compounds in the pyrolysates from the tobacco cell-wall polysaccharides cellulose, hemicellu-lose, and pectins. They noted that these biopolymeric polysaccharides constituted 30% to 50% of the dry weight of the tobacco they were studying. Sakuma et al. pyrolyzed tobacco-derived cellulose (3401), chlorogenic acid, and rutin (3400) and reported various aldehydes and ketones plus numerous phenols in the pyrolysates. Many of the pyrolysate components identified have also been identified in cigarette MSS. 

The chemical composition of biomass materials is generally discussed in terms of cell wall polysaccharides (cellulose and hemicelluloses), phenolics (lignin and polyphenols), extractives, and ash content. Wood normally contains small amounts of ash (1 percent) and various quantities of extractives... 

Cellulose is found in groups of microorganisms like fungi, bacteria, and algae. In green algae, cellulose, xylan, or mannan may serve as stmctural cell wall polysaccharides. Cellulose is found, although in small quantities, in all of the brown... 

Tokoh, C., Takabe, K., Sugyiama, J., Fujita, M., 2002. Cellulose synthesis by Acetobacter xylinum in the presence of plant cell wall polysaccharides. Cellulose 9, 65—74. 

This essay was written in an attempt to explain our overview of primary cell walls and to reach consensus on the nomenclature of primary cell wall polysaccharides. We present evidence supporting the hypothesis that cellulose, xyloglucan, arabinoxylan, homogalacturonan, RG-I, and RG-II are the six polysaccharides common to all primary cell walls of higher plants. In many cells, these six polysaccharides account for all or nearly all of the primary wall polysaccharides. Like the physically interacting proteins that constitute the electron transport machinery of mitochondria, the structures of the six patently ubiquitous polysaccharides of primary cell walls have been conserved during evolution. Indeed, we hypothesize that the common set of six structural polysaccharides of primary cell walls have been structurally... 

Figure 3. Distribution of polysaccharides through the cell wall. C, cellulose M, galacto-glucomannan X, arabino-4-O-methylglucuronoxylan.

The polysaccharide compositions of potato cell walls have been genetically manipulated for two main reasons first to attempt to understand the functions of the different cell-wall polysaccharides, and second to improve the value of potato pulp waste. The yield of pectin extracted from the pulp would be improved by decreasing the proportion of cellulose in the walls. The gelling quality of this pectin would also probably be improved by reducing the proportion of RG-1 side chains (Sorensen et al., 2000). 

Brown, R. M., Herth, W., Franke, W. W., Romanovicz, D. The role of the Golgi apparatus in the biosynthesis and secretion of a cellulosic glycoprotein in Pleurochrysis a model system for the synthesis of structural polysaccharides. In Biogenesis of plant cell wall polysaccharides, pp. 207. Loewus, F. (ed.). New York Academic Press 1973... 

Synthesis of Cell Wall Polysaccharides Plant Cellulose and Bacterial Peptidoglycan 775... 

The standard procedure by Saeman et al. (I) involves manual stirring of the polysaccharide with 72% H2S04, standing at 30°C, and secondary hydrolysis at 100° or 120°C in a steam autoclave. While certain resistant polysaccharides are still incompletely depolymerized, decomposition of the more sensitive monosaccharides formed cannot be avoided. An alternative method by using trifluoroacetic acid was applied successfully for plant cell wall polysaccharides by Albersheim et al. (2) and for dissolving pulps and hemicelluloses by Fengel et al. (3). Highly crystalline cellulose was not well dissolved and not completely hydrolyzed by CFsCOOH. 

The term hemicellulose is applied to those plant cell-wall polysaccharides which occur in close association with cellulose, especially in lignified tis-... 

The list of pyrolysis products of cottonwood shown in Table VII (llj reflects the summation of the pyrolysis products of its three major components. The higher yields of acetone, propenal, methanol, acetic acid, CO, water and char from cottonwood, as compared to those obtained from cellulose and xylan, are likely attributed to lignin pyrolysis. Other results are similar to those obtained from the pyrolysis of cell-wall polysaccharides. This further verifies that there is no significant interaction among the three major components during the thermal degradation of wood. 

Finally, the question of the average degree of polymerization (d.p.) of the gluean chains must be considered. Determinations of the d.p. of polysaccharides are usually made by viscosity measurements, but native cellulose, being highly insoluble and often in close association with other cell-wall polysaccharides and lignin, presents special prob-... 

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