Title: Purification and characterization of an extracellular α-amylase from Bacillus subtilis AX20
Abstract: A Bacillus subtilis AX20 from soil with ability to produce extracellular α-amylases was isolated. The characterization of microorganism was performed by biochemical tests as well as 16S rDNA sequencing. Maximum amylase activity (38 U/ml) was obtained at stationery phase when the culture was grown at 37 °C. The enzyme was purified to homogeneity with an overall recovery of 24.2% and specific activity of 4133 U/mg. The native protein showed a molecular mass of 149 kDa composed of a homodimer of 78 kDa polypeptide by SDS–PAGE. The optimum pH and temperature of the amylase were 6 and 55 °C, respectively. The enzyme was inhibited by Hg2+, Ag2+, and Cu2+ and it did not show an obligate requirement of metal ions. The enzyme was not inhibited by EDTA or EGTA, suggesting that this enzyme is not a metalloenzyme. The end products of corn starch and soluble starch were glucose (70–75%) and maltose (20–25%). Rapid reduction of blue value and the end products suggest an endo mode of action for the amylase. The purified amylase shows interesting properties useful for industrial applications.
Publication Year: 2005
Publication Date: 2005-06-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 110
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