An Acidophilic beta-Galactosidase from Bispora sp MEY-1 with High Lactose Hydrolytic Activity under Simulated Gastric Conditions

作者：Wang Hui; Luo Huiying; Bai Yingguo; Wang Yaru; Yang Peilong; Shi Pengjun; Zhang Wei; Fan Yunliu; Yao Bin^*

来源：Journal of Agricultural and Food Chemistry, 2009, 57(12): 5535-5541.

DOI：10.1021/jf900369e

• Acidophilic
• Bispora sp MEY-1
• beta-galactosidase
• simulated gastric fluid

BgalA, a full-length gene (3,009 bp) that encodes a beta-galactosidase, was cloned from the meso-acidophilic fungus Bispora sp. MEY-1 and expressed in Pichia pastoris. The deduced amino acid sequence of BgalA shares highest identity (55.5%) with the beta-galactosidase from Aspergillus phoenicis, which belongs to the glycoside hydrolyase family 35. Purified recombinant BgalA is acidophilic, exhibiting maximum activity at pH 1.5, which is lower than that reported for other beta-galactosidases. The enzyme has high pH and thermal stability and is resistant to proteases and cations found in milk. The K(m) and V(max) of BgalA for 2-nitrophenyl-beta-D-galactopyranoside and lactose are 5.22 mM and 120.8 mu mol/(min.mg), and 0.31 mM and 137.3 mu mol/(min.mg), respectively. Under simulated gastric conditions, BgalA has greater stability (similar to 100%) and hydrolysis ratio (>80%) toward milk lactose than the commercially available beta-galactosidase from Aspergillus oryzae (ATCC 20423). Thus, BgalA may be a better digestive supplement for alleviating symptoms associated with lactase deficiency.

• 出版日期2009-6-24
• 单位中国农业科学院