abstract
Previous research has shown that the laccase-catalyzed oxidation of lignin fibers containing wood can improve the strength of fibreboard Medium density. In the present study it was examined whether laccase treatment had no effect on the tensile strength of unbleached kraft pulp yield high. Treatment with laccase alone had only a very small effect on the wetstrength pulp, that the addition of lignin rich extractives increased the wetstrength after enzyme treatment significantly. Mediated oxidation gave a similar improvement of the wet tensile strength, although no lignin was added to the fiber suspension. Furthermore, it was found that heat treatment combined with a mediated oxidation resulted in greater improvement in wet tensile strength that could be addressed by individual care. No change in the dry tensile strength of laccase treatment was observed. It is suggested that the observed improvement wet tensile strength is related to the polymerization of the lignin on the fibers in the sheet of hands and / or the coupling of phenoxy radicals on the lignin associated with adjacent fibers. For different mediators studied, a correlation was found between oxygen consumption during oxidation and mediated generation wetstrength in the pulp.
Previous research has shown that the laccase-catalyzed oxidation of lignin fibers containing wood can improve the strength of fibreboard Medium density. In the present study it was examined whether laccase treatment had no effect on the tensile strength of unbleached kraft pulp yield high. Treatment with laccase alone had only a very small effect on the wetstrength pulp, that the addition of lignin rich extractives increased the wetstrength after enzyme treatment significantly. Mediated oxidation gave a similar improvement of the wet tensile strength, although no lignin was added to the fiber suspension. Furthermore, it was found that heat treatment combined with a mediated oxidation resulted in greater improvement in wet tensile strength that could be addressed by individual care. No change in the dry tensile strength of laccase treatment was observed. It is suggested that the observed improvement wet tensile strength is related to the polymerization of the lignin on the fibers in the sheet of hands and / or the coupling of phenoxy radicals on the lignin associated with adjacent fibers. For different mediators studied, a correlation was found between oxygen consumption during oxidation and mediated generation wetstrength in the pulp.
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