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An Acidophilic and Acid-Stable β-Mannanase from Phialophora sp. P13 with High Mannan Hydrolysis Activity under Simulated Gastric Conditions
- Zhao, Junqi, Shi, Pengjun, Luo, Huiying, Yang, Peilong, Zhao, Heng, Bai, Yingguo, Huang, Huoqing, Wang, Hui, Yao, Bin
- Journal of agricultural and food chemistry 2010 v.58 no.5 pp. 3184-3190
- beta-mannosidase, acid tolerance, Phialophora, mannans, hydrolysis, in vitro digestion, food technology, fungi
- A β-mannanase gene, man5AP13, was cloned from Phialophora sp. P13 and expressed in Pichia pastoris. The deduced amino acid sequence of the mature enzyme, MAN5AP13, had highest identity (53%) with the glycoside hydrolase family 5 β-mannanase from Bispora sp. MEY-1. The purified recombinant β-mannanase was acidophilic and acid stable, exhibiting maximal activity at pH 1.5 and retaining >60% of the initial activity over the pH range 1.5-7.0. The optimum temperature was 60 °C. The specific activity, Km and Vmax for locust bean gum substrate were 851 U/mg, 2.5 mg/mL, and 1667.7 U/min·mg, respectively. The enzyme had excellent activity and stability under simulated gastric conditions, and the released reducing sugar of locust bean gum was significantly enhanced by one-fold in simulated gastric fluid containing pepsin in contrast to that without pepsin. All these properties make MAN5AP13 a potential additive for use in the food and feed industries.