A Novel Raw Starch Hydrolyzing Thermostable α-Amylase Produced by Newly Isolated Bacillus mojavensis SO-10: Purification, Characterization and Usage in Starch Industries

Abstract

ABSTRACT The aim of this study is the production, purification, and characterisation of thermostable raw starch hydrolyzing α-amylase produced by Bacillus mojavensis SO-10. The maximum production conditions of α-amylase were found at 36th hour, 35 °C and pH 7.0. We utilized three steps to purify the thermostable α-amylase and as a result, 34-fold and 18% yield were obtained. The molecular weight of purified α-amylase was determined as 73 kD. The Km and Vmax rates were detected as 0.010 mM and 3.38 µmol min−1, respectively. This purified α-amylase exhibited the highest activity at pH 5.0-6.0 and 70 oC and showed stability over a wide variety of pH and temperature at 4.0-8.0, and 40-50 oC, respectively. The thermostable purified α-amylase exhibited stability in the presence of denaturing agents and heavy metal ions. The purified enzyme hydrolyzed the raw starches of corn and wheat grains in the ratio of 36.7% and 39.2% respectively. The end-yields of soluble starch hydrolysis were analyzed by thin-layer chromatography (TLC). In addition, the usage of purified α-amylase in clarification of apple juice and domestic washing detergent industries were evaluated.