Purification and characterization of novel thermostable and Ca-independent α-amylase produced by Bacillus amyloliquefaciens BH072

Abstract In the present study, a novel α -amylase produced by Bacillus amyloliquefaciens BH072 was purified and characterized. The molecular weight of purified α -amylase was approximately 68 kDa, determined by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and ten amino acid of N-terminal was NSGLNGYLTH. The kinetic parameters K m and V max were 4.27 ± 0.21 mg/mL and 987.34 ± 23.34 U/mg, respectively. Purified α -amylase showed maximal activity at pH 7 and 60 °C. Enzyme remained stable in pH range 6.0–7.0 and 50–80 °C. The activity of the α -amylase was Ca 2+ independent and stability in the presence of surfactant, oxidizing and bleaching agents. The β -mercaptoethanol and EDTA greatly enhanced and reduced α -amylase activity, respectively. This enzyme has high hydrolysis rate toward corn, wheat and potato starch and hydrolyzes soluble starch to glucose, maltose, maltotriose and maltotetraose, indicating that the α -amylase represents a promising candidate for applications in the food industry.