Author/Authors :
-، - نويسنده Department of Biology, Faculty of Science, University of Guilan, P.O. Box 41335-1914, Rasht, Iran Mahdavi, Atiyeh , -، - نويسنده Department of Biology, Faculty of Science, University of Guilan, P.O. Box 41335-1914, Rasht, Iran Hassan Sajedi, Reza , -، - نويسنده Department of Biology, Faculty of Science, University of Guilan, P.O. Box 41335-1914, Rasht, Iran Rassa, Mehdi , -، - نويسنده Department of Biology, Faculty of Science, University of Guilan, P.O. Box 41335-1914, Rasht, Iran Jafarian, Vahab
Abstract :
Bacillus sp. GUF8, isolated from acidic soil samples of a tea farm was identified as Bacillus cereus, based on 16S rDNA sequencing and standard bacterial identification methods. Following optimization of enzyme production, the resulting α-amylase was purified by acetone precipitation and ion exchange chromatography. Consequently, thermostability and kinetic parameters of the purified enzyme were determined. The temperature profile of the enzyme indicated a very broad temperature range (from 10 to 70°C) with 50°C representing the optimum temperature for enzyme activity, which is different from those of the known Bacillus a-amylases. This enzyme was optimally active at pH 6.0 and retained 75 and 50% of its maximal activity at pH 8.0 and 9.0, respectively. It was also strongly inhibited by Zn2+ and partially inhibited by Ni2+ and ethylenediaminetetraacetic acid (EDTA). The a-amylase enzyme was found to hydrolyze starch forming various maltooligosaccharides, such as maltose (G2) and maltopentaose (G5) as major products.
