Spruce holocellulose

Percentage Composition of Easily Hydrolyzable Hemicellvloses in Spruce Holocellulose... 

Table I. Hydrolysis of Polyoses A from Spruce Holocellulose with 72(%) Sulfuric Acid and 2N TFA6...

The whole procedure normally takes about 1 hr. The acid is then evaporated, and the dry matter can be analyzed. This method can be applied to cellulose from wood, as a-cellulose or pulp, or to other celluloses (e.g., cotton) as well as to cellulosic materials with higher amounts of other polysaccharides (e.g., holocellulose). The chromatograms of the hydrolysates of a-cellulose from beechwood and of holocellulose from sprucewood (Figure 6) are examples of the application of this method. Compared with sulfuric acid hydrolysis, the total sugar yield from the spruce holocellulose is higher after the hydrolysis with concentrated TFA (Table II). Regarding the individual sugars, it can be seen that the... 

Avicelase or Cellobiohydrolase + Mannanase. The treatment of spruce holocellulose first with avicelase or cellobiohydrolase and subsequently with mannanase effected an overall intensive degradation of... 

Following previous attempts to isolate a pure mannan from wood, Hess and Liidtke reported the isolation of such a polymer from a spruce sulfite pulp. Husemann, much later, obtained a similar product from a spruce holocellulose. It is now clear that these polysaccharides could not possibly have been mannans. Wise and Ratliff found that over half of the D-mannose residues in black spruce wood are intimately associated with the a-cellulose portion, perhaps as an integral part of the cellulose. A skinlike substance, insoluble in cuprammonia, was isolated by Rollin-... 

Figure IL The SEC molar mass distribution curves for arabino-4-O-methyl-glucuronoxylan (from spruce holocellulose), arabinohexenuronoxylan (kraft pulp) and two different 4 0-methylglucuronoxylans (sulfite and dissolving pulp) obtained by the SEC/MALDI-MS procedure. Each xylan was analyzed separately employing the alkaline (pH 13) buffer SEC system and subsequently graphed on the same MALDI-MS calibrated absolute molar mass scale.

For the study of soluble polysaccharides, a treatment with diluted TFA is sufficient and the reaction time can be kept short (7). Soluble polysaccharides of wood are separated from holocellulose by extraction with alkali. Wise et al. (10) term the extract with 5% KOH polyoses (hemicelluloses) A. Polyoses A can be hydrolyzed completely with 2N TFA within 1 hr. The chromatograms of the hydrolysates of polyoses A from spruce and beech holocelluloses recorded with a sugar analyzer (Biotronik ZA 5100) are shown in Figure 1. 

Table II. Hydrolysis of Holocellulose from Spruce With 72(%) Sulfuric Acid° and 100(%) TFA6...

Figure 5. Holocellulose of spruce-wood tracheid. Control sample...

The removal of xylan by the xylanase appeared more pronounced in T than in Si. This is in disagreement with microdensitometrical evaluations of substance losses in cell walls of spruce- and pinewood holocellulose reported by Boutelje and co-workers (5,6). They found that the hydrolysis of xylan by xylanase treatment occurred mainly in the S2 layer the Si and in some cases also the S3 (T) layer appeared not to be affected. In the same way, they showed that the Si layer is more resistant to cellulolytic attack than the other cell wall layers. 

Further work in Canada to produce rigid wet-process insulation boards from a bark-wood mixture was reported by Branion in 1961 (36). He made boards containing 85% poplar wood and 15% white spruce bark a few boards were made with added poplar or jack pine bark. White spruce bark worked best it appeared to cause a significant increase in tensile strength compared to boards made from 100% poplar wood fiber. This effect also was demonstrated in a hardboard. Other boards were made with up to 80% bark. Water absorption decreased as bark content increased. An effort was made to discover the bark ingredient responsible for the strength increase. After a series of extractions, the active component was concluded to be present in the holocellulose. 

In one study, an arabino-(4-0-methylglucurono)xylan of pine had to be isolated in the pure form without the use of any alkaline reagents. A chlorite holocellulose was extracted with methyl sulfoxide, followed by hot water. The product from the latter extraction was dissolved in water, and a xylan-rich fraction was precipitated by adding cetyltrimethyl-ammonium bromide. When a chlorite holocellulose of spruce was extracted with methyl sulfoxide and then with water, the former extract was richer in xylan, and the latter in glucomannan. ... 

The fir, hemlock,and spruce galactoglucomannans have been nitrated, and the nitrates subjected to measurements of osmotic pressure. The number of D-glucose and D-mannose residues per average molecule was found to be 76, 44, and 100, respectively. The low yield of the spruce polymer suggests that the polymer consists of a fraction of high molecular weight. All of the specimens had probably been depolymerized by the chlorous acid used in preparing the holocelluloses. 

Figure 5. Relation of polyethylene glycol molecular weight to nonsolvent water content for waterlogged whole wood for superswollen wood (NaOH-treated, acid-washed sugar maple) for cellophane (water washed, air-dried, and rewetted) and for holocellulose (Sitka spruce)...

Amylose and starch, both derived from potato, were commercial samples. Glucomannan and xylan were isolated from spruce and beech holocelluloses, respectively, and purified by the usual method (12). Pectin was isolated and purified from the midrib of Nicotiana taba-cum and kindly provided by Dr. Shigeru Eda at The Central Research Institute, Japan Tobacco Inc. ( ). 

Only very few investigations by means of thermal analysis are found in the literature. Reh and Kraepelin [51] applied DSC and chemical analyses to spruce samples of two ring densities and observed thermograms with different peak heights for holocellulose (around 350°C) and lignin (around 490 C), respectively... 

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