A Neutral Thermostable beta-1,4-Glucanase from Humicola insolens Y1 with Potential for Applications in Various Industries

作者：Xu, Xinxin; Li, Jinyang; Zhang, Wei^*; Huang, Huoqing; Shi, Pengjun; Luo, Huiying; Liu, Bo; Zhang, Yuhong; Zhang, Zhifang; Fan, Yunliu; Yao, Bin

来源：PLos One, 2015, 10(4): e0124925.

DOI：10.1371/journal.pone.0124925

• PHIALOPHORA SP G5
• ENZYMATIC-PROPERTIES
• CELLULASES
• ENDOGLUCANASE
• CELLULOSE
• DEGRADATION
• PURIFICATION
• SYNERGY
• CLONING
• MODE

We cloned a new glycoside hydrolase family 6 gene, Hicel6C, from the thermophilic fungus Humicola insolens Y1 and expressed it in Pichia pastoris. Using barley beta-glucan as a substrate, recombinant HiCel6C protein exhibited neutral pH (6.5) and high temperature (70 degrees C) optima. Distinct from most reported acidic fungal endo-beta-1,4-glucanases, HiCel6C was alkali- tolerant, retaining greater than 98.0, 61.2, and 27.6% of peak activity at pH 8.0, 9.0, and 10.0, respectively, and exhibited good stability over a wide pH range (pH 5.0-11.0) and at temperatures up to 60 degrees C. The Km and V-max values of HiCel6C for barley beta-glucan were 1.29 mg/mL and 752 mu mol/min.mg, respectively. HiCel6C was strictly specific for the beta-1,4-glucoside linkage exhibiting activity toward barley beta-glucan, lichenan, and carboxy methylcellulose sodium salt (CMC-Na), but not toward laminarin (1,3-beta-glucan). HiCel6C cleaved the internal glycosidic linkages of cellooligosaccharides randomly and thus represents an endo-cleaving enzyme. The predominant product of polysaccharide hydrolysis by HiCel6C was cellobiose, suggesting that it functions by an endo-processive mechanism. The favorable properties of HiCel6C make it a good candidate for basic research and for applications in the textile and brewing industries.

• 出版日期2015-4-24
• 单位中国农业科学院