Purification of α-Amylase from Bacillus sp. GHA1 and Its Partial Characterization

Bacillus sp. GHA1 was isolated from water samples and screened for the production of α-amylase. Maximum production of amylase by this strain occurs at 42 ºC, pH 6.5 and 72 h after cultivation in production medium. The enzyme was purified through successive applications of ammonium sulfate precipitation, ion exchange and hydrophobic interaction chromatography, resulting in a single band with an apparent molecular weight of 66 kDa, as judged by SDS-PAGE. Calcium analysis of the purified enzyme revealed that it contained three metal ions per molecule. The new extracellular α-amylase is active in a wide range of pH with its maximum activity at pH values 5.5-8.0. The optimum temperature for enzyme activity is 57 ºC and the presence of calcium has relatively low influence on its activity and thermostability. The Bacillus sp. GHA1 α-amylase with these properties may be suitable for use in detergent and food industries