S7木聚糖酶辅助非木浆DQP漂白的效果

Performance of Xylanase S7 for DQP Bleaching of Non-Wood Kraft Pulps

使用重组毕赤酵母基因工程菌发酵所得的S7木聚糖酶对麦草浆、芦苇浆、竹浆3种非木浆进行预处理(70℃,pH9.0),随后进行无元素氯DQP漂白,并与两种商品酶AU-PE89和Pulpzyme HC的助漂效果进行比较.结果表明,使用等量的化学助漂剂时,在高温强碱的条件下进行预处理的S7木聚糖酶,可将非木浆白度提高1%ISO以上,并可降低非木浆的卡伯值,提高非木浆的物理强度,效果与商品酶相近.通过扫描电子显微镜观察发现,经酶处理的纤维表面出现明显变化.

Three kinds of non-wood pulps, namely, wheat straw pulp, reed pulp and bamboo pulp, were pretreated at 70℃ and pH9.0 with xylanase S7 secreted by recombinant Pichia pastoris and were then treated with chlorine- free DQP bleaching. Then, the aid-bleaching effect of xylanase S7 was compared with those of two kinds of commercial xylanases AU-PE89 and Pulpzyme HC. The results indicate that, with the same bleaching reagent consumption, the non-wood pulps treated with xylanase S7 are of a brightness increment of more than 1% ISO, a lower Kappa number and better physical properties, which means that xylanase S7 possesses an aid-bleaching effect similar to those of the commercial enzymes. Moreover, it is found from SEM results that, after the enzymatic pre-treatment, the fiber surface changes obviously.