REACTIONS OF ISOLATED CELLULASES, HEMICEL LULASES AND LIGNINASES WITHFIBROUS MATERIALS AND ISOLATED COMPONENTS OF WOOD

The complete degradation of cellulose is effected by the synergistic a ction of cello-biohydrolases, endoglucanases and beta-glucosidases. Ev en now there is much uncertainty concerning substrate specificity and method of action of particular enzymes, and also concerning the kind o f their combined action. However, there is agreement that crystalline cellulose is degraded by two immunologically differing cello-biohydrol ases, one or more endoglucanases and at least one glucosidase. Example s, as far as are known, are given of the action of particular enzymes of the cellulose systems, concerning soluble and unsoluble substrates. During recent years further knowledge has been gained, especially con cerning the enzymes which degrade Xylan and Mannan. This concerns espe cially such enzymes which selectively split acetyl, glucuronosyl, arab inosyl and galactosyl sidegroups from the main chains of the Xylanes a nd Mannans. Examples of targetted modification of hemicelluloses throu gh application of these enzymes are elucidated. During this time it ha s also been possible to deepen the knowledge concerning the action of ligninases. In contrast to the enzymes which split polysaccharides, li gninases act non-specifically and require a number of further pre-cond itions to make their practical application possible.