In alkaline pH, Bacillus tequilensis TB5 can grow and produce amylase but amylase activity decreases because the concentration of H+ ions (or protons) is too low. Affecting the interactions between R-groups of the amino acids in the protein chains that make up the enzyme and interactions include hydrogen bonds, ionic bonds, and Van der Waals forces. Therefore, the enzyme specific shape no able binding substrate at active site and reaction will not take place. Therefore, the amylase activity decreases.