Fig. 3. The optimum temperature (a) thermal stability (b) optimum pH (c) and pH stability (d) of purified amylase was investigated. (a) The effect of temperature on amylase
activity was studied by incubation of the enzyme at temperatures ranging from 20 to 100 C and then, enzyme activity was determined. (b) The temperature stability of
amylase was measured at various temperatures ranging from 20 to 95 C for 1 h, and then the residual activity was measured. (c) Effect of pH on the amylase activity was
measured. Residual enzyme activity was determined against soluble starch at range of pH 3.0–11.0. (d) Effects of pH on the stability of amylase was assayed. The enzyme
activity was determined against starch at various pHs. The pH stability of the amylase was studied by pre-incubating the enzyme at different pH for 1 h at 70 C. The
percentage of residual activities was calculated based on the original enzyme activity and taken as 100%.