Saha B C
Fermentation Biochemistry Research Unit, National Center for Agricultural Utilization Research, Agricultural Research service, United States Department of Agriculture, Peoria, Illinois 61604, USA.
Appl Microbiol Biotechnol. 2001 Sep;56(5-6):762-6. doi: 10.1007/s002530100716.
A fungus, Fusarium verticillioides (NRRL 26518), was isolated by screening soil samples using corn fiber xylan as carbon source. The extracellular xylanase from this fungal strain was purified to apparent homogeneity from the culture supernatant by ultrafiltration using a 30,000 cut-off membrane, octyl-Sepharose chromatography and Bio gel A-0.5 m gel filtration. The purified xylanase (specific activity 492 U/mg protein; MW 24,000; pI 8.6) displayed an optimum temperature at 50 degrees C and optimum pH at 5.5, a pH stability range from 4.0 to 9.5 and thermal stability up to 50 degrees C. It hydrolyzed a variety of xylan substrates mainly to xylobiose and higher short-chain xylooligosaccharides. No xylose was formed. The enzyme did not require metal ions for activity and stability.
通过以玉米纤维木聚糖作为碳源筛选土壤样品，分离出了一种真菌，即轮枝镰孢菌（NRRL 26518）。使用截留分子量为30,000的膜进行超滤、辛基琼脂糖层析和Bio gel A - 0.5m凝胶过滤，从该真菌菌株的培养上清液中纯化出细胞外木聚糖酶，使其达到表观纯一性。纯化后的木聚糖酶（比活性为492 U/mg蛋白质；分子量24,000；等电点8.6）的最适温度为50℃，最适pH为5.5，pH稳定范围为4.0至9.5，热稳定性可达50℃。它将多种木聚糖底物主要水解为木二糖和更高的短链木寡糖，不形成木糖。该酶的活性和稳定性不需要金属离子。
