J. Iran. Chem. Soc., Vol. 7, No. 2 June 2010, pp.432~440.

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

A. Ahmadia, S. Ghobadia,*, K. Khajehb, B. Nomanpourc and A. Badoei Dalfardb

aDepartment of Biology, Faculty of Science, Razi University,67149-67346, Kermanshah, Iran
bDepartment of Biochemistry, Faculty of Science, Tarbiat Modarres University, P.O. Box 14115-175, Tehran, Iran
cDepartment of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

Bacillus sp. GHA1 was isolated from water samples and screened for the production of a-amylase. Maximum production of amylase by this strain occurs at 42 °C, 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 a-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 °C and the presence of calcium has relatively low influence on its activity and thermostability. The Bacillus sp. GHA1 a-amylase with these properties may be suitable for use in detergent and food industries.

Keywords: α-Amylase, Bacillus sp. GHA1, pH profile, Broad range of pH, Industrial applications

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