Monday, April 30, 2007 - 10:40 AM

Hydrolysis of cellulose -the water point of view

Claus Felby1, Lisbeth Thygesen1, Jan Bach Kristensen2, Henning Jørgensen1, and Thomas Elder3. (1) Danish Center for Forest and Landscape, Faculty of Life Sciences, Copenhagen University, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark, (2) Forest and Landscape Denmark, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark, (3) Utilization of Southern Forest Products, USDA-Forest Service, Southern Research Station, 2500 Shreveport Highway, Pineville, LA 71360

Within a cellulose matrix water will exist in several different states depending on its immediate surroundings; as water with properties close to unbound water, as tightly bound water forming a high density layer on the surface of cellulose fibrils or as loosely bound water restricted by the adjacent cellulose matrix.
Using low field NMR not only can the different forms of water in a cellulose matrix be identified, but also the effect of cellulases on the different water states can be studied.
Using filter paper as a model substrate the effect of endo- and exo-cellulases on the state of water is measured as well as the time dependant development of the hydrolysis.
An immediate effect upon the cellulose-water interactions can be seen when cellulases are applied. Also individual enzymes show different effects on the cellulose-water interaction. The effect of cellulases on the cellulose-water interactions can be seen in both a change of the transverse relaxation times as well as a difference in the distribution between different water states.
The results of this work may enable a better description of not only the role of water during cellulose hydrolysis, but also it may give new information on the interactions between cellulose and enzymes as well as the long debated importance of high density water on the cellulose surface.