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Laccase is a copper-containing polyphenol oxidase. As a wood-degrading enzyme laccase can degrade lignin in the organism. Laccase redox potential is relatively low, 300 to 800 mV (standard hydrogen electrode), only the oxidative degradation of lignin phenol structural units, but not the oxidation accounted for 90% of the lignin phenol structural unit. If there is a low molecular weight compound as a redox mediator, laccase oxidation of non-phenolic lignin structural unit. Such as ABTS (2,2 '- hydrazine - bis (3 - ethyl - benzothiazol-6 - sulfonic acid)), HBT (1 - hydroxybenzotriazole), VIO (Violet uric acid), MS (eugenol methyl), PTC (promethazine hydrochloride), PPT (phenothiazine -10 - propionic acid), PT (phenothiazine). Masson pine groundwood pulp has a high yield, low production costs, environmental friendliness; However, due to the relatively low intensity of the production of paper, whiteness instability and other shortcomings, which seriously hampered the masson pine groundwood wood pulp in papermaking applications on high-grade paper. Therefore there is a need to be modified. Laccase / mediator system Masson pine groundwood pulp modification, and the modification mechanism. At present, the nature used to pulp performance improvement of small molecules more, and there are quite a few synthetic, some material may be modified groundwood pulp. Its modifying effect on the pulp due to the different structure of the dielectric body, but also the type, it is necessary to first dielectric body preferably. Under certain conditions, the laccase / mediator-modified comparative tests of groundwood pulp. The study found that the modification effect of the laccase / purple uric acid (VIO) best by laccase / the VIO modified groundwood pulp higher whiteness, but also the strength of the pulp significantly enhanced. The laccase / the VIO modified masson pine groundwood pulp optimum conditions, the conditions were: 2.5% pulp consistency, pass oxygen, the the mediator amount of 1% (relative to the dry pulp) The amount of laccase LAMU / g, enzyme treatment time of 60 min, the role of laccase temperature of 55 ° C. Under this condition, by the whiteness of the pulp modified decreased, but the strength of the pulp is significantly increased. Compared with the control pulp, after hydrogen peroxide bleaching, the pulp whiteness and strength has increased significantly. This shows that the laccase / mediator at the same time to improve the performance of groundwood pulp, the pulp can drift increases. Determination of Laccase and laccase / mediator treatment the oxygen concentration in the pulp process, and to explore the laccase / mediator of the lignin in the pulp, the type of reaction activity and catalytic oxidation reaction kinetics under different conditions, a dissolved oxygen analyzer. In the different mediator laccase synergy in the pulp process, laccase / VIO processing pulp showed a higher rate of oxygen consumption. Laccase alone when treating pulp, oxygen faster in the initial few minutes, a few minutes after the oxygen concentration substantially constant. Mediator VIO alone with the pulp role in the process, the oxygen concentration did not change significantly. Paint enzyme / VIO treating pulp, within 20 minutes can consume the oxygen in the container. In the paint and laccase / VIO treatment process of lignin model compounds, oxygen concentration trend is basically similar and pulp, but the reaction rate is faster. The laccase / the VIO treatment of pulp and lignin model compounds oxygen concentration changes over time was once exponential decay. SEM, FQA, FT-IR, GC-MS analysis on the the laccase / the VIO modified stone groundwood mechanism was discussed. SEM and FQA analysis found paint enzyme / VIO processing pulp fiber surface becomes rough, raising phenomenon between the fiber closely intertwined; fiber length and roughness were decreased. FT-IR and GC-MS analysis showed that, the laccase / VIO processed pulp filtrate was guaiac lignans, a carbonyl group, and some small molecular weight substances generated. This shows that lignin dissolved in the the laccase / VIO modified pulp process, indeed, more hydrogen bonds formed between the fibers, enhanced binding force between the fibers, thereby improving the pulp property.
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