Effects of Xylanase Treatment before and after Bleaching on the Properties of Wheat Straw Pulp

Xylanase was used to enhance the bleaching of wheat straw pulp.The process of the treatment with xylanase from Trichoderma reesei Rut-30 and effects of xylanase treatment before and after bleaching on the properties of wheat straw pulp were investigated.The results indicated that the suitable conditions for xylanase treatment were:temperature 45℃,pH value 5.4～6.5,pulp consistency 5%,time 60 min,enzyme dosage 5 IU/g.The yield of the pulp treated with xylanase before bleaching or after bleaching droped some extent compared with the control pulp,and the yield drop of the pulp with xylanase treatment after bleaching was even worse than that of the pulp with xylanase treatment before bleaching; the brightness of the pulp treated with xylanase after bleaching increased 3.5 units(SBD)and 5.4 units(SBD)compared with the pulp treated with xylanase before bleaching and the control pulp respectively.The breaking length and bursting index of the pulp treated with xylanase before bleaching were higher and the tear index was lower than that of the pulp treated with xylanase after bleaching.