重组极耐热木聚糖酶和重组极耐热漆酶协同漂白麦草浆

利用来自海栖热袍茵的重组极耐热木聚糖酶XynB和来自嗜热栖热菌Thermus thermophilus HB27的重组极耐热漆酶Tth-laccase对麦草浆进行协同漂白。结果表明,当未漂浆经XL漂序处理(X:重组木聚糖酶用量20 U/g绝干浆,pH 5.8,温度90℃,浆浓8%,处理时间2 h;L:重组漆酶用量3 U/g绝干浆,pH 4.5,温度90℃,浆浓8%,处理时间1.5 h),可获得最佳漂白效果。与对照浆比较,XL处理使浆料白度提升11.5%ISO,卡伯值降低6.9。双酶协同处理在改善浆料可漂性的同时,对纸浆纤维强度无负面影响。在后续过氧化氢漂白段中,当漂终白度相近时,XL预处理浆可节省约50%H_2O_2消耗量。

Biobleaching of wheat straw pulp with hyperthermophilic recombinant xylanase/laccase system

The recombinant laccase from the hyperthermophilic bacteria Thermus thermophilus HB27 and the recombinant xylanase from the hyperthermophilic bacteria Thermotoga maritima MSB8 were applied jointly to biobleaching of wheat straw pulp. The best bleaching effect was boosted when the pulp was treated with X treatment （20 U xylanase g-1 dry pulp at 90 ℃, pH 5.8, 8% consistency for 2 h） preceded L bleaching stage （3 U laccase g-1 dry pulp at 90 ℃, pH 4.5, 8% consistency for 1.5 h） , Under these conditions, brightness of the bleached pulp was increased by 11.5% ISO, and kappa number of pulp was decreased by 6.9. Enzymatic treatment improved the bleachability of wheat straw pulp but caused no damage to the pulp fibers. The use of XL-treated pulp saved nearly 50% H_20_2 consumption in subsequent peroxide bleaching when the same final brightness results were obtained.