Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
J Agric Food Chem. 2010 Apr 28;58(8):4814-8. doi: 10.1021/jf9045792.
Xylanase A from Paenibacillus barcinonensis, a new species isolated from a rice field, has been cloned and expressed in Escherichia coli. Purified recombinant xylanase showed high activity on xylans from hardwoods and cereals, and exhibited K(m) and V(max) of 2.93 mg/mL and 50.67 U/mg on birchwood xylan. Xylanase A was highly active at 60 degrees C in alkaline pH values up to 9.5 and remained stable for at least 3 h in alkaline conditions. The amino acid sequence deduced from xynA revealed that it is a single domain xylanase belonging to the GH10 family. Thin layer chromatography analysis showed that the enzyme released a mixture of hydrolysis products including substituted xylooligomers from cereal arabinoxylans, while xylose, xylobiose, and aldotetraouronic acid were the main products released from glucuronoxylan from birchwood. The enzyme released a complex mixture of xylooligomers for acetylated xylan from eucalyptus, revealing its potential to depolymerize this widely used resource in the pulp and paper industry.
来自米田土壤中新物种巴氏芽胞杆菌的木聚糖酶 A 已被克隆并在大肠杆菌中表达。纯化的重组木聚糖酶对硬木和谷物来源的木聚糖具有很高的活性，对桦木木聚糖的 K(m)和 V(max)分别为 2.93mg/mL 和 50.67U/mg。木聚糖酶 A 在 60°C 碱性 pH 值高达 9.5 的条件下具有很高的活性，并且在碱性条件下至少稳定 3 小时。从 xynA 推导出的氨基酸序列表明，它是一种属于 GH10 家族的单一结构域木聚糖酶。薄层层析分析表明，该酶从谷物阿拉伯木聚糖中释放出取代的低聚木糖水解产物的混合物，而从桦木木聚糖释放出的主要产物是木糖、木二糖和醛四糖。该酶从桉树乙酰化木聚糖中释放出复杂的低聚木糖混合物，显示出其在纸浆和造纸工业中广泛使用的资源进行解聚的潜力。
