Purification and Characterization of a Novel Thermostable and Acid Stable A-Amylase from Bacillus Sp. Iranian S1

This study describes the purification and biochemical characterization of a novel thermostable and acidic ph stable ? -amylase from bacillus sp.iranian s1 which isolated from the desert soil (gandom-e-beryan in lut desert, iran). maximum enzyme production was in exponential phase with activity 2.93 u ml-1 at 50°c and ph 5. the enzyme was purified by isopropanol sedimentation, ion-exchange chromatography on deae cellulose de-52 and gel filtration on sephadex g-100. the purification procedure performed for ?-amylase enzyme achieved about 98.9-fold purification with 25% yield and specific activity 375.9 u mg-1 of protein. the molecular weight of purified ?-amylase was estimated around 70 kda by sds-page and it was stable in a wide range of temperature and ph between 30°c- 110°c and 3-9, respectively. assayed with soluble starch as substrate, the enzyme displayed optimal activity at 90°c and ph 5. the purified ?-amylase was acid- and thermo-stable with novel properties making it suitable for many industrial purposes.