Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
Bioresour Technol. 2013 Feb;130:161-7. doi: 10.1016/j.biortech.2012.12.067. Epub 2012 Dec 20.
Three xylanase genes (xynA, xynB, xynC) of glycosyl hydrolase family 10 were identified in Humicola insolens Y1. The deduced protein sequences showed the highest identity of ⩽83% to known fungal xylanases and of ⩽38% with each other. Recombinant XynA-C produced in Pichia pastoris showed optimal activities at pH 6.0-7.0 and at high temperature (70-80°C), and exhibited good stability over a broad pH range and temperatures at 60°C. The gene xynC produced by H. insolens Y1 (named XynW) was similar in enzyme properties with XynC expressed by Pichia. XynA exhibited better alkaline adaptation and thermostability, and had higher catalytic efficiency and wider substrate specificity. Under simulated mashing conditions, addition of XynA-C showed better performance on filtration acceleration (37.4%) and viscosity reduction (13.5%) than Ultraflo from Novozyme. Thus the three xylanases represent good candidates for application in the brewing industry.
从康宁木霉 Y1 中鉴定到 3 个属于糖苷水解酶家族 10 的木聚糖酶基因（xynA、xynB、xynC）。推导的蛋白序列与已知真菌木聚糖酶的同源性最高为 ⩽83%，彼此之间的同源性最高为 ⩽38%。在巴斯德毕赤酵母中表达的重组 XynA-C 在 pH6.0-7.0 和高温（70-80°C）下表现出最佳活性，并在较宽的 pH 范围和 60°C 温度下表现出良好的稳定性。康宁木霉 Y1 产生的基因 xynC（命名为 XynW）与毕赤酵母表达的 XynC 在酶特性上相似。XynA 表现出更好的碱性适应性和热稳定性，具有更高的催化效率和更广泛的底物特异性。在模拟糖化条件下，与诺维信的 Ultraflo 相比，添加 XynA-C 可使过滤加速（37.4%）和黏度降低（13.5%）效果更好。因此，这 3 种木聚糖酶是酿造工业应用的良好候选酶。
