A thermophilic α-galactosidase from Neosartorya fischeri P1 with high specific activity, broad substrate specificity and significant hydrolysis ability of soymilk

An extracellular α-galactosidase (Gal27A) with high specific activity of 423 U mg−1 was identified in thermophilic Neosartorya fischeri P1. Its coding gene (1680 bp) was cloned and functionally expressed in Pichia pastoris. Sequence analysis indicated that deduced Gal27A contains a catalytic domain of glycoside hydrolase family 27. The native and recombinant enzymes shared some similar properties, such as pH optima at 4.5, temperature optima at 60–70 °C, resistance to most chemicals and saccharides, and great abilities to degrade raffinose and stachyose in soymilk. Considering the high yield (3.1 g L−1) in P. pastoris, recombinant rGal27A is more favorable for industrial applications. This is the first report on purification and gene cloning of Neosartorya α-galactosidase.