Biochemical Characterization of α-Galactosidase-Producing Thermophilic Bacillus coagulans KM-1

A bacterium producing α -galactosidase ( α - D -galactoside galactohydrolase, EC 3.2.1.22) was isolated. The isolate, KM-1 was identified as Bacillus coagulans based on its 16S rRNA sequence, morphology, and biochemical properties. α -Galactosidase activity was detected the culture supernatant of B. coagulans KM-1. The bacterium showed the maximum activity for hydrolyzing para-nitrophenyl- α - D -galactopyranoside (pNP- αGal ) at pH 6.0 and 50∘C . It hydrolyzed oligomeric substrates such as melibiose, raffinose, and stachyose liberating a galactose residue, indicating that the B. coagulans KM-1 α -galactosidase hydrolyzed α -1,6 linkage. The results suggest that the decreased stachyose and raffinose contents in fermented soybean meal are due to the α -galactosidase activity.