木聚糖酶（xylanase, EC 3.2.1.8）可以随机切割木聚糖主链的β-1,4-糖苷键，在饲料、食品、造纸和纺织等领域具有广泛的应用。本研究通过分子克隆技术将黑曲霉CICIM F0510来源的木聚糖酶基因xynC在毕赤酵母中进行了克隆表达，构建获得了重组菌GS115 (pPIC-xynC)。在摇瓶水平上，重组菌的酶活为1.14 U/mL。酶学性质的研究表明，重组酶XynC的最适反应温度和pH分别为30 ℃和2.5，且它在25～40 ℃或pH 2.0～5.0有较好的稳定性；K⁺对XynC的活性有微弱的促进作用，而Ca²⁺、Co²⁺、Mn²⁺、Zn²⁺、Cu²⁺、Fe³⁺、Sn²⁺、EDTA和SDS等对XynC的活性有不同程度的抑制作用。此外，该酶还可以水解戊聚糖产生聚合度为3～6的低聚木糖。这些良好的理化性质为重组酶XynC在饲料及食品等领域的应用奠定了基础。

Xylanase, an enzyme that randomly cleaves internal β-1,4-xylosidic linkages of xylan backbone, has wide applications in feed, food, pulp and paper, and textile industries. In the present study, gene xynC encoding xylananse from Aspergillus niger CICIM F0510 was cloned and expressed in Pichia pastoris, and the recombinant strain GS115 (pPIC-xynC) was subsequently constructed. At the shake flask level, the activity of the recombinant enzyme XynC was 1.14 U/mL. The optimum temperature and pH of XynC was determined to be 30 ℃ and 2.5, respectively. This enzyme was also stable at 25-40 ℃ or pH 2.0-5.0. K⁺ slightly enhanced the activity of XynC, whereas Ca²⁺, Co²⁺, Mn²⁺, Zn²⁺, Cu²⁺, Fe³⁺, Sn²⁺ EDTA and SDS had different inhibitory effects on its activity. Besides, XynC can hydrolyze pentosan to yield short chain xylooligosaccharides with degree of polymerization of 3-6. Such good biochemical properties lay a solid foundation for the applications of XynC in feed and food fields.