Molecular Characterization of a New Alkaline-Tolerant Xylanase from Humicola insolens Y1. (5th January 2015)

• Record Type: Journal Article
• Authors: Shi, Pengjun; Du, Yanlong; Yang, Hong; Huang, Huoqing; Zhang, Xiu; Wang, Yaru; Yao, Bin
• Other Names: Kalafatis Michael Academic Editor.
• Is Part Of: BioMed research international. Volume 2015(2015)
• Publication Date: 2015-01-05
• Subjects: Medicine -- Periodicals; Biology -- Periodicals; Biotechnology -- Periodicals; Life sciences -- Periodicals; 610.5
• DOI: 10.1155/2015/149504
• Languages: English
• ISSNs: 2314-6133

Abstract

Abstract : An endo-1, 4- β -xylanase-encoding gene, xyn11B, was cloned from the thermophilic fungus Humicola insolens Y1. The gene encodes a multimodular xylanase that consists of a typical hydrophobic signal sequence, a catalytic domain of glycoside hydrolase (GH) family 11, a glycine-rich linker, and a family 1 carbohydrate binding module (CBM1). Deduced Xyn11B shares the highest identity of 74% with a putative xylanase from Podospora anserina S mat+. Recombinant Xyn11B was successfully expressed in Pichia pastoris and purified to electrophoretic homogeneity. Xyn11B had a high specific activity of 382.0 U mg −1 towards beechwood xylan and showed optimal activity at pH 6.0 and 50°C. Distinct from most reported acidic fungal xylanases, Xyn11B was alkaline-tolerant, retaining 30.7% of the maximal activity at pH 9.0. The K m and V max values for beechwood xylan were 2.2 mg mL −1 and 462.8 μ mol min −1 mg −1, respectively. The enzyme exhibited a wider substrate specificity and produced a mixture of xylooligosaccharides. All these favorable enzymatic properties make Xyn11B attractive for potential applications in various industries.