Purification and Characterization of Thermostable α-Amylase from Soil Bacterium Bacillus sp.

Abstract

Background: Amylases are used in several industrial and biotechnological sectors, including those producing textiles, detergents, paper and bakery products. Objective: This study aimed to purify an industrially important α-amylase from Bacillus sp. For this purpose, a single and rapid α-amylase purification was performed using the starch affinity method. Methods: Characterization of the purified enzyme was determined by investigating temperature, pH stability, detergents, and metal ions. Results: The purification coefficient of 29.8-fold with a yield of 9.2% was found. The molecular weight of the purified α-amylase was determined to be 53 kDa by SDS-PAGE, and thermostability was confirmed with 100% activity at 30ºC and 40ºC after 1 h. The purified enzyme was stable over a wide range of pH values, with optimum activity at pH 6.0, 7.0 and 8.0 after 2 h. The study also investigated the effects of the metal ions and detergents on the purified amylase and found that Mg2+ and Ca2+ ions were the activators of the enzyme, while Zn2+, Co2+ and Na+ ions decreased the activity. Furthermore, Hg2+ indicated complete inhibition of amylase activity. The detergents Triton X-100 and Tween 20 increased the α-amylase activity, while sodium dodecyl sulfate inhibited the activity. Conclusion: The purified α-amylase obtained from Bacillus sp. is considered to be environmentally friendly, can be processed in a short time, and has a low cost.