Cello-oligosaccharides

Coumarin (2H-l-benzopyran-2-one) is a known inhibitor of cellulose formation,355-357 and Hopp and coworkers358 found that, in membranes from the alga Prototheca zopfii, it inhibits the transfer in vitro of the lipid-linked cello-oligosaccharide to its protein acceptor (see Section II,2,b). 

Figure 13. Taper chromatogram of the hydrolysis products from cello-oligosaccharides by Ex-1. Developed by the descending technique for 72 hr at room temperature on Whatman No. 1 paper, using 1-butanol pyridine water (6 4 3, v/v) as a solvent (S) standard, (Gt) glucose, (Ge) cellobiose, (Gs) cellotriose, (Gu) cellotetraose, (G5) cellopentaose, (G6) cellohexaose final enzyme concentration 3.0 X 10 2%.

Further studies verified the intermediate formation of free radicals, as demonstrated by the electron-spin resonance spectra obtained during autooxidation of cellulose,75 and hydrogen peroxide was identified as a byproduct in the autooxidation of D-glucitol. Similar oxidations of cellulose in the presence of alkenic monomers afforded graft copolymers. The autooxidation of cellulose and of the cello-oligosaccharides was shown to be more extensive in the presence of transition-metal cations. 

Vrsanska, M. and Biely, P., The cellobiohydrolase I from Trichoderma reesei QM 9414 Action on cello-oligosaccharides. Carbohydrate Res 1992, 227, 19 27. 

Engle, A.R. Hyatt, J.A. Purdie, N. Induced circular dichroism study of the aqueous solution complexation of cello-oligosaccharides and related polysaccharides with aromatic dyes. Carbohydr. Res. 1994, 265, 181-195. 

From the quantitative analysis of hydrolysis products from cellotetra-ose and reduced cellotetraose by the three cellulases, the bond 2, when the glucosyl bonds of the cello-oligosaccharides were numbered from the nonreducing end, was found to be hydrolyzed more easily than the bond 3 by any of the three cellulases. With higher cello-oligosaccharides, all... 

Discrimination of Cellulase Components A, B, and C. The physical and chemical properties as well as substrate specificities of the highly purified cellulases of Ps. fluorescens have been characterized and are summarized in Table IV. Cellulase A is different from Cellulase B in the mobility on zone electrophoresis and in the pattern of Sephadex G-25 chromatography, but similar in substrate specificity toward several reduced and nonreduced cello-oligosaccharides. On the other hand, Cellulase C is different from A in the pattern of DEAE-Sephadex chromatography and the substrate specificity, and from B in all respects. These characteristics of each cellulase component are therefore different enough to be used as criteria to discriminate one from the other. 

Ps. fluorescens var. cellulosa synthesized a large amount of cellulase in 0.5% cellulose or sophorose medium, and more than 90% of the enzyme formed was released in surrounding medium (exo-type synthesis). In contrast, smaller amounts of cellulase were formed upon cultures on 0.5% cello-oligosaccharides, and more than 90% of the enzyme remained within the cells (endo-type synthesis). Since the major soluble end-products of cellulolysis by Pseudomonas cellulases in vitro were cellobiose and cellotriose (28), the direct C-source utilized by the bacterium should be these sugars even if either cellulose or cello-oligosaccharides were used as C-source. The only difference between these cultures, therefore, may be in the concentration of the end-products in each medium. 

Studies of 12 different Penicillium species have demonstrated that there was a coinduction between cellulolytic and xylanolytic activities whether the substrate was cellulose or xylan, whereas activities of cellulolytic enzymes were generally higher during growth on cellulose than on xylan [28]. The conclusion was further confirmed by our studies of P. decumbens (data not shown). Together with the above results of starch and protein experiments, it must be the high levels of water soluble cello-oligosaccharides... 

Effects of Cello-oligosaccharides on Production of Extracellular Cellulase and Xylanase... 

Table 1 Effects of cellobiose and cello-oligosaccharides supplements on growth and production of extracellular cellulase and xylanase (enzyme activities per gram mycelia mass).

MCC microcrystalline cellulose, CB cellobiose, COS cello-oligosaccharides (the mixture of cellotetraose, cellopentose and cellohextose)... 

Taken together, the results of this research demonstrate the importance of knowing and regulating the starch and soluble protein contents of wheat bran supplements from different sources when adding wheat bran to stimulate cellulase and xylanase production by P. decumbens. Our results also predict that adding cello-oligosaccharides directly to P. decumhens fermentation could significantly improve industrial-scale biomass hydrolysis by P. decumbens. 

The n.m.r. spectra of peracetylated cello-oligosaccharides have been recorded and compared with that of cellulose acetate.All of the signals from cellulose acetate were only observed in the spectra of cellotetraose and cello-pentaose peracetates. Some signals were not observed in the spectra of cellobiose and cellotriose peracetates. 

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