Modification of wood properties through enzymes
2005
Wagenfuehr, A. | Tech, S. (Technische Universitaet Dresden, Dresden (Germany). Institut fuer Holz- und Papiertechnik) | Unbehaun, H.
The addition of phenol oxidising enzyme preparations leads to change in the fibre structure of lignocellulose products. This means that positive material properties can be selectively put in. In the production of materials the use of activated ownfibre binding forces only makes sense when the production process ensures that fibres are as close to one another as possible. This can be accomplished by fine tuning the density of the material to the method in question. Material densities of over 600 kg/m3 are necessary for dry method approaches. With wet methods, on the other hand, the properties of material can be improved starting from a density of 160 kg/m3. A good distribution and the use of additionally created hydro-bridge builders are responsible for this. The employment of charge carriers during the processing with a wet method also has a positive influence on the physical properties. The suspended particles that become detached from the fibre in the process bind together and are concentrated on the surface of the fibre. To improve the steering of the process with the wet method further enzymatic treatment steps in lignocellulose can be carried out with micro- and nano-particle systems. This can be done via combinations of cationic starch or cationic polyacrylamide. With these systems the cationic polymer is added to the fibre suspension first, followed by the micro-particle components. Both the levels of additives used and the required incubation times can thereby be markedly reduced. Here for the first time we succeeded in using enzymes in processing technically relevant dimensions and were therefore able to renounce the addition of synthetic binding means without impairing the properties of the material.
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