Cellobiose preparation from cellulose

The most common naturally occurring disaccharides are sucrose (table sugar) and lactose (milk sugar). While sucrose is derived from plants and is prepared commercially from sugar cane and sugar beet, lactose is found in the milk of animals. Other common disaccharides that are produced by breaking down polysaccharides include maltose (obtained from starch) and cellobiose (obtained from cellulose). 

Degradation of oat and barley glucans with Streptomyces cellulase, which produces mainly cellobiose and cellotriose from cellulose, resulted in production of a trisaccharide fraction and a tetrasaccharide fraction as the major products. These were isolated by preparative paper-chromatography, and the trisaccharide was found to preponderate ... 

A new procedure described for the determination of cellulase activity is based on incubation of the enzyme with finely divided cellulose at pH 6.9 and determination of the D-glucose and cellobiose liberated as their trimethylsilyl derivatives by g.l.c. The method, although generally applicable, was specifically developed for measurement of cellulase activity in mixed enzyme preparations from sheep rumen contents the coefficient of variation of the assay was 2.4-4.5%. 

Cellulases enzymes which hydrolyse cellulose to cellobiose, and which are found in plants, bacteria and fungi, TTie C. of Penicillium notatum is well-studied it consists of 324 amino acid residues (M, 35,000) with a disulfide bridge and no free SH groups. C. are used in digestion tablets, to remove undesired cellulose in foods, and for the preparation of cellobiose from cellulose. 

Preparation (36). Cellulose in the form of cotton or filter paper is simultaneously acetylated and acetolyzed by the action of acetic anhydride and sulfuric acid at low temperatures. Cellobiose octaacetate crystallizes from the reaction mixture and after separation is recrystallized from alcohol. The acetyl groups are removed by any of several methods, preferably with barium methoxide in methanol solution. 

Crystalline cellobiose has been obtained from hydrolyzates of cellulose by a cell-free enzyme preparation from Aspergillus niger (37). An enzyme... 

Oligosaccharides result from the condensation of two to ten monosaccharide molecules through glycosidic bonds. Acid hydrolysis easily breaks these bonds enzymatic hydrolysis breaks them with high specificity. Saccharose (glucose + fructose) is the most abundant disaccharide. At present, most of the warm waxes for hair removal are prepared from saccharose (Tannir and Leshin, 2001). Maltose and cellobiose are degradation products of starch and cellulose polymers, respectively. 

This particular trimethylglucose is unique in that it was separated in crystalline form from the hydrolyzates of the methyl ethers of several naturally-occurring glucose polymers almost two decades before it was synthesized from glucose. These natural sources, which still furnish the most convenient routes for the preparation of 2,3,6-trimethyl-D-glucose, include maltose,124-128 cellobiose,127,128 lactose,122-181 starch,71,182 glycogen,188,184 cellulose,185-187 and lichenin. 188,189 The literature pub-... 

In 1972 Ogawa and Toyama (56) purified three components— A-I-a, A-I-b, and A-II-1—which were adsorbed on a gauze column during purification from Cellulase Onozuka P1500, a commercial preparation of T. viride cellulase. These three components had molecular weights of 32,000, 48,000, and 48,000 as determined by gel filtration and contained 7-16% carbohydrate. Each is reported to carry out the random hydrolysis of CM-cellulose and to degrade hydrocellulose (Avicel) and cellooligosaccharides except for cellobiose. The order of reactivity toward either cotton or Avicel was A-II-1 > A-I-b > A-I-a. The proteins adsorbed on cellulose comprised 38% of the total cellulase protein. 

Pilnik al (7) have noted that the combined action of pecti-nases and C-1 (1,4-p-D-glucan cellobiohydrolase, E.C. 3.2.1.91) enriched cellulases are able to almost completely liquefy pulped fruits and vegetables. For the actual dissolution of the cristal-line cellulose fibrils the C-1 enzyme is necessary which splits off cellobiose from the non-reducing end of the 1,4-p-D-glucan and which needs some C-x (1,4-p-D-glucan-glucanohydrolase, E.C. 3.2.1.4) to create such points of attack. Preparations rich in C-1 activity are usually obtained from Trichoderma spp. (8). 

Electrophoretic properties of typical cellulase preparations, an extracellular cellulase from a culture on 0.5% cellulose and a cell-bound cellulase from that on 0.5% cellobiose, were compared in respect to their behavior in zone electrophoresis on cellulose acetate film. As shown in Figure 2, the former was separated into two components, A (fast moving to the cathode) and B (almost no moving). With the latter, a single component was detected under the same conditions. This fast moving component was in approximate agreement with component A in regard to its mobility, but as will be mentioned later, there was considerable difference in substrate specificity and other properties. Therefore, it seems to be a different component, and is referred to as component C. 

An insoluble, enzyme preparation (sedimenting at 100,000 g) has been obtained by Glaser it is capable of catalyzing the transfer of D-gluco-pyranosyl residues from uridine 5-(a-D-glucopyranosyl-C pyrophosphate) to form a radioactive, water-insoluble, alkali-insoluble polysaccharide. This product was identified as cellulose by (a) hydrolysis with the cellulase of Myrotkecium verrucaria, and (b) identification, as cellobiose, of the radioactive disaccharide obtained by acid hydrolysis—by repeated recrystallization with authentic cellobiose without loss of specific activity. 

Amorphous D-glucose was prepared by quenching from molten D-glucose and amorphous cellulose was prepared by saponification of cellulose triacetate film using 1% sodium ethylate dissolved in anhydrous ethanol. -D-glucose and cellobiose were obtained commercially. Cellulose I is natural cellulose. 

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