Characterization of an acidophilic and thermostable α‐amylase from Alicyclobacillus sendaiensis NUST

This paper describes the characterization of an acidophilic and thermostable α‐amylase from Alicyclobacillus sendaiensis NUST. The MW of this enzyme was estimated to be 56 kDa by SDS–PAGE. The enzyme was stable over a range of pH from 2.5 to 5.5 with an optimum around 3.5. Maximum activity of the α‐amylase was observed at pH 3.5 and 85°C in the presence of soluble starch as substrate. The enzyme activity was decreased by Mg²⁺, Cu²⁺, Zn²⁺, Al³⁺, K⁺, Li⁺, Ag⁺, urea, EDTA, trichloroacetic acid and Tween 60 and inhibited by Hg²⁺, Ce²⁺ and SDS, whereas the activity was increased by Mn²⁺, DTT, and β‐mercaptoethanol. Ca²⁺and Fe²⁺ did not affect the enzyme activity.