Microbial acid-stable α-amylases: Characteristics, genetic engineering and applications

► Acidic amylases suit starch and baking industries as native starch is acidic. ► Ca2+-independent, thermo-acid-stable α-amylases are unavailable commercially. ► The directed evolution and structural studies of acidic α-amylase are highlighted. ► There is no review available on acidic α-amylases in the published literature.