Characterization of α-Galactosidase and β-Glucosidase by Weissella cibaria

A strain producing α-galactosidase and β-glucosidase was isolated from Kimchi. The isolated strain was identified as Weissella cibaria by 16S rDNA analysis and designated as Weissella cibaria K-M1-4. The enzyme activity of α-galactosidase and β-glucosidase reached the maximum in the soy medium at 37℃ for 24 hr. The enzymes were purified by ethanol fractionation, DEAE sepharose fast flow, and sephacryl S-100HR column chromatography. α-Galactosidase specific activity was shown by 576 Units/mg protein and the yield was 3.5% of the total activity of crude extracts. β-glucosidase specific activity was shown by 480 Units/mg protein and the yield was 2.9% of the total activity of crude extracts. The optimum temperature for α-galactosidase was 60℃ and 43% of its original activity remained when it was treated at 80℃ for 30 min. For α-galactosidase shows the optimum pH of 8.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of Fe²+ and Cu²+. The value of Km and Vmax for the enzyme were 0.98 mM and 1.81 μmole/min, respectively. The β-glucosidase has the optimum temperature of 50℃ and 46% of its original activity remained when it was treated at 80℃ for 30min. Its optimum pH of 7.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of Fe²+, Co²+ and Cu²+. The value of Km and Vmax for the enzyme were 1.24 mM and 6.81 μmole/min, respectively.