Taneja Kavita, Gupta Saurabh, Kuhad Ramesh Chander
Department of Microbiology, University of Delhi, New Delhi, India.
Bioresour Technol. 2002 Oct;85(1):39-42. doi: 10.1016/s0960-8524(02)00064-0.
An alkalophilic Aspergillus nidulans KK-99 produced an alkaline, thermostable xylanase (40 IU/ml) in a basal medium supplemented with wheat bran (2% w/v) and KNO3 (at 0.15% N) pH 10.0 and 37 degrees C. The partially purified xylanase was optimally active at pH 8.0 and 55 degrees C. The xylanase was stable in a broad pH range of 4.0-9.5 for 1 h at 55 degrees C, retaining more than 80% of its activity. The enzyme exhibited greater binding affinity for xylan from hardwood than from softwood. The xylanase activity was stimulated (+25%) by Na+ and Fe2+ and was strongly inhibited (maximum by 70%) by Tween-20, 40, 60, SDS, acetic anhydride, phenylmethane sulphonyl fluoride, Triton-X-100. The xylanase dose of 1.0 IU/g dry weight pulp gave optimum bleach boosting of Kraft pulp at pH 8.0 and temperature 55 degrees C for 3 h reaction time.
嗜碱构巢曲霉KK - 99在添加了麦麸（2% w/v）和KNO₃（氮含量0.15%）、pH值为10.0且温度为37℃的基础培养基中产生了一种碱性、耐热木聚糖酶（40 IU/ml）。部分纯化的木聚糖酶在pH 8.0和55℃时活性最佳。该木聚糖酶在55℃下于4.0 - 9.5的宽pH范围内稳定1小时，保留超过80%的活性。该酶对硬木中的木聚糖表现出比对软木中的木聚糖更强的结合亲和力。Na⁺和Fe²⁺刺激木聚糖酶活性（增加25%），而吐温 - 20、40、60、SDS、乙酸酐、苯甲基磺酰氟、曲拉通 - X - 100则强烈抑制其活性（最大抑制70%）。在pH 8.0、温度55℃和3小时反应时间下，1.0 IU/g干重纸浆的木聚糖酶剂量能使硫酸盐浆的漂白效果达到最佳。
