An overview of the microbial ?-amylase family.

Amylases are enzymes which hydrolyze the starch molecules into polymers composed of glucose units. α-Amylases are ubiquitous in distribution, with plants, bacteria and fungi being the predominant sources. Most of the microbial α-amylases belong to the family 13 glycosyl hydrolases, and they share several common properties. But different reaction specificities have been observed across the family members. Structurally α-amylases possess (β/α) 8 or TIM barrel structures and are responsible for hydrolysis or formation of glycosidic bonds in the α-conformation. Stability of the α-amylases has been widely studied; pH and temperature have very important roles to play. Engineering the enzymes for improved stability enhances their use industrially. This review focuses on the distribution, structuralfunctional aspects and factors for enhancing the stability of α-amylases.