Cellulase composition

Provide an improved cellulase composition decrease strength loss... 

The cambium was isolated firom spruce (Picea abies) logs felled in October-November. The bark was stripped off, and the cambium was removed by gentle scraping. The isolated cambium was immediately fiozen in liquid nitrogen and fi-eeze-dried. The carbohydrate composition of the isolated cambium was analysed by HPLC after enzymatic hydrolysis using Pectinex Ultra and a mixture of cellulases and hemicellulases (Buchert et al 1993). 

Water removal on the paper machine has been shown to improve as a result of limited hydrolysis of the fibres in recycled paper. Mixtures of cellulases and hemicellulases were found to decrease the SR-value, which describes the drainage behaviour of the fibres (45), The effect is apparently due to fibrillation or change in the composition of fine particles. 

Figures 1 and 2 show positive correlation, although of varying degrees of goodness of fit, between the specific activities of endo ucanase, exoglucanase, and -glucosidase activities with the cellulose composition and degradation in digester feed, respectively. These data indicate a direct relationship between the cellulose content in the feed and cellulase enzyme complex production by the digester consortia. In this system, as in many others studied, cellulose is an effective inducer of cellulase secretion (67,68),...

Our first detailed analysis of the cellulase system produced on wheat straw in SSF indicated that the activities of various enzymes were as follows (lU/ml) FP cellulase, 8.6 -glucosidase, 10.6 and xylanase, 190-480. The FP cellulase -glucosidase ratio was 1 1.23 (21), These results encouraged us to compare the composition of the cellulase systems produced in SSF and LSF on different substrates. 

Table IV. Composition of Cellulase Systems of Trlchoderma reesel QMY-1 produced on Wheat Straw and Wheat Bran Under Liquid and Solid-State Fermentation...

Table V. Composition of Cellulase System Produced on Pro-cell with Trichoderma reesei QMY-1 in SSF...

Table VI. Composition of Cellulase Systems Produced in Solid-State Fermentation...

Comparison of Composition of Cellulase Systems of Various Fungi Produced in SSF... 

Table IV. Amino Acid Composition of Various Cellulase Components from I. lacteus°...

Tt is a widely recognized fact that true cellulolytic microorganisms A produce three basic cellulase components IS), and that these enzyme components act in concert to hydrolyze crystalline cellulose to glucose (6). Many research laboratories have undertaken the task to purify cellulose components from various cellulolytic microorganisms and to study the mechanisms of cellulose hydrolysis. Much information has accumulated concerning the mode of action of cellulose hydrolysis since Reese et al. first proposed the Ci-C concept (7). In spite of this, however, conflicting reports still flourish concerning the composition of the "cellulase complex, the multiplicity of cellulase components, the biosynthesis of cellulose, and the mechanisms of cellulose hydrolysis. 

The amino acid composition of many / -( l- 4) glycoside hydrolases, including cellulases (27-30), xylanases (15,31,32,33), and mannanases (34) have been determined. In general, the enzymes contain higher than... 

In contrast to cellulases, the hemicellulases encompass a much broader suite of activities. In addition to analogue versions of endo-, exo-, and glycosidase cellulase activities, multiple debranching activities are needed to handle the high complexity of the heterogeneous hemicelluloses (Table 33.3). The varied backbone composition of hemicelluloses also adds complexity. Xylans, xyloglucans, man-nans, and numerous other minor polysaccharide chains form the backbone for different hemicelluloses. 

Table III. Amino Acid Compositions of Fungal Cellulases...

The amino acid contents of the proteins are generally similar. Each enzyme has high levels of aspartic acid and glycine but less of the basic amino acids. The compositions of hydrocellulase C and Cellulase IV closely resemble each other, with 15 of the 16 amino acids reported having the same relative abundance in the respective proteins. 

The D-xylanase system of Stereum sanguinolentum,199 the only D-xylanase for which an amino acid composition has as yet been published, was found to contain a high proportion of acidic and aromatic amino acid residues. The M.W., as determined from the amino acid composition, is 23,900, compared with 21,600 as calculated from ultracentrifugation data. Other physical parameters that have been determined199 for this D-xylanase include the sedimentation coefficient [2.8S, which is similar to that reported for a D-xylanase isolated from Trichoderma viride,203 namely, 2.IS], the partial specific volume (0.71 cm3.g 1), and the molar extinction coefficient (6.25 X 104). Activation energies have been reported for D-xylanases from Schizophyllum commune233 (EA 28.6 kj.mol-1) and from a commercial cellulase preparation229 (EA 34.0 kj.mol-1). 

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