An overview of the microbial α-amylase family

Abstract

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, structural
functional aspects and factors for enhancing the stability of α-amylases.