Authors: Fan Zhang Pengjun Shi Yingguo Bai Huiying Luo Tiezheng Yuan Huoqing Huang Peilong Yang Lihong Miao Bin Yao
Publish Date: 2010/12/01
Volume: 89, Issue: 6, Pages: 1851-1858
Abstract
An endoβ14xylanase gene designated xyn10G5 was cloned from Phialophora sp G5 and expressed in Pichia pastoris The 1197bp fulllength gene encodes a polypeptide of 399 amino acids consisting of a putative signal peptide at residues 1–20 a family 10 glycoside hydrolase domain a short Gly/Thrrich linker and a family 1 carbohydratebinding module CBM The deduced amino acid sequence of XYN10G5 shares the highest identity 534 with a putative xylanase precursor from Aspergillus terreus NIH2624 The purified recombinant XYN10G5 exhibited the optimal activity at pH 40 and 70 °C remained stable at pH 30–90 70 of the maximal activity and was highly thermostable at 70 °C retaining ~90 of the initial activity for 1 h Substrate specificity studies have shown that XYN10G5 had the highest activity on soluble wheat arabinoxylan 3506 U mg−1 and moderate activity to various heteroxylans and low activity on different types of cellulosic substrates Under simulated gastric conditions XYN10G5 was stable and released more reducing sugars from soluble wheat arabinoxylan when combined with a glucanase CelA4 the viscosity of barley–soybean feed was significantly reduced These favorable enzymatic properties make XYN10G5 a good candidate for application in the animal feed industryThis work was supported by the Earmarked Fund for Modern Agroindustry Technology Research System NYCYTX42G205 and the Key Program of Transgenic Plant Breeding 2009ZX08003020B and the Agricultural Science and Technology Conversion Funds grant 2008 GB23260388
Keywords: