A thermostable Gloeophyllum trabeum xylanase with potential for the brewing industry

• Published in: Food chemistry Vol. 199; pp. 516 - 523
• Main Authors: Wang, Xiaoyu, Luo, Huiying, Yu, Wangning, Ma, Rui, You, Shuai, Liu, Weina, Hou, Lingyu, Zheng, Fei, Xie, Xiangming, Yao, Bin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.05.2016
• Subjects: Cloning, Molecular; Digestion; Endo-1,4-beta Xylanases - chemistry; Fermentation; Gloeophyllum trabeum; Glycoside hydrolase family 10 (GH10); Industrial Microbiology; Pichia - genetics; Thermo-tolerant; Xylanase; Thermo-tolerant; Xylanase; Gloeophyllum trabeum; Glycoside hydrolase family 10 (GH10)
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2015.12.028

•An acid tolerant xylanase with an optimal temperature of 75°C.•A versatile xylanase with significant glucan and p-nitrophenol-β-cellobiose activities, which is protease resistant.•Improved mashing performance of filtration rate and viscosity reduction.•The mutation of Gly48 to Asp, Arg or Lys result in different temperature optima. A xylanase gene of glycoside hydrolase family 10, GtXyn10, was cloned from Gloeophyllum trabeum CBS 900.73 and expressed in Pichia pastoris GS115. Purified recombinant GtXyn10 exhibited significant activities to xylan (100.0%), lichenan (11.2%), glucan (15.2%) and p-nitrophenol-β-cellobiose (18.6%), demonstrated the maximum xylanase and glucanase activities at pH 4.5–5.0 and 75°C, retained stability over the pH range of 2.0–7.5 and at 70°C, and was resistant to pepsin and trypsin, most metal ions and SDS. Multiple sequence alignment and modeled-structure analysis identified a unique Gly48 in GtXyn10, and site-directed mutagenesis of Gly48 to Lys improved the temperature optimum up to 80°C. Under simulated mashing conditions, GtXyn10 (80U) reduced the mash viscosity by 12.8% and improved the filtration rate by 31.3%. All these properties above make GtXyn10 attractive for potential applications in the feed and brewing industries.