Abstract
Based on its α-amylase activity at pH 5.0 and optimal pH of the crude enzyme, a strain (named B-5) with acid α-amylase production was screened. The B-5 strain was identified as Bacillus amyloliquefaciens through morphological, physiological, and biochemical characteristics analysis, as well as 16S rDNA phylogenetic analysis. Its α-amylase gene of GenBank Accession No. GU318401 was cloned and expressed in Escherichia coli. The purified recombinant α-amylase AMY-Ba showed the optimal pH of 5.0, and was stable at a pH range of 4.0-6.0. When hydrolyzing soluble starch, amylose, and amylopectin, AMY-Ba released glucose and maltose as major end products. The α-amylase AMY-Ba in this work was a different type from the well-investigated J01542 (GenBank Accession No.)-type α-amylase from the same species. AMY-Ba exhibited notable adsorption and hydrolysis ability towards various raw starches. Structure analysis of AMY-Ba suggested the presence of a new starch-binding domain at its C-terminal region.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Bacillus / cytology
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Bacillus / enzymology*
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Bacillus / genetics
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Bacillus / metabolism
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Bacterial Typing Techniques
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Cloning, Molecular
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DNA, Bacterial / chemistry
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DNA, Bacterial / genetics
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DNA, Ribosomal / chemistry
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DNA, Ribosomal / genetics
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Enzyme Stability
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Gene Expression
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Genetic Testing
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Glucose / metabolism
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Hydrogen-Ion Concentration
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Maltose / metabolism
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Microscopy, Electron, Scanning
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Molecular Sequence Data
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RNA, Ribosomal, 16S / genetics
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Sequence Analysis, DNA
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Starch / metabolism
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alpha-Amylases / chemistry
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alpha-Amylases / genetics*
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alpha-Amylases / isolation & purification
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alpha-Amylases / metabolism*
Substances
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DNA, Bacterial
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DNA, Ribosomal
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RNA, Ribosomal, 16S
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Recombinant Proteins
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Maltose
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Starch
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alpha-Amylases
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Glucose