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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.