Study on Pinus Massonian Kraft Pulp Bleaching by Laccase/Xylanase System

LXS(laccase-xylanase system) was obtained after regulated cultivation on Flammulina velutipes. We used LXS in the pretreatment of pinus massonia kraft pulp, and then operated DED bleaching to this pulp as well as making a comparison of the result with the LMS (laccase-mediator system) pretreatment. The result showed that the conditions of the optimal process were as following: pH 4.2, pulp consistency 3%, temperature 40 degrees C; treatment time 3hr; enzyme dosage 10 IU.g(-1). Alkaline extraction was applied on the Pulp after LXS pretreatment, and the kappa number reduced 9.2% compared with the control pulp. In contrast, the kappa number of the pulp by LMS pretreatment reduced 8.3% compared with the control pulp. When DED bleaching was applied on the pulp after pretreatment, the brightness of the pulp by LXS pretreatment was 6.0% higher than that of the control pulp and was quite close to the brightness of the pulp by LMS pretreatment. Moreover, the strength of these two pulps was similar and it had no obvious decrease than that of the control pulp.