Effect of temperature , pH , substrate ( Starch ) and glucose on stability of α - amylase from Bacillus licheniformis ATCC 6346

Thermostable α-amylases (1,4-α-D-glucan glucanohydrolase; E.C.3.2.1.1) from Bacillus species are of great industrial importance in the production of corn syrup or dextrose. The present study was aimed to determine the effect of temperature, pH, substrate and glucose on stability of α-amylase from Bacillus licheniformis ATCC 6346. To determine the effect of temperature and pH on the stability of α-amylase this was pre-incubated at different temperatures and pHs. The enzyme pre-incubated with starch and glucose separately at 85C to determine the effect of substrate and endproduct on the stability of α-amylase. Crude -amylase retained 60% of the original activity when it was pre-incubated at 85C for 10 min. This enzyme was more stable at pH 9.0 than other pH values (7.0 and 8.0) and no significant important was observed with addition of substrate (starch). Presence of glucose slightly increased the stability of -amylase. There was no significant improvement in the stability of -amylase was observed with the addition of starch however presence of glucose slightly increased the stability of the α-amylase.