Kinetics and thermodynamic studies of alpha amylase from Bacillus licheniformis mutant

The present investigation deals with the purification and characterization of enzyme α-amylase from a mutant strain of bacillus licheniformis ems-6. a laboratory scale stirred fermentor of 7.5 l capacity was used for the enzyme production under optimal conditions. the enzyme was purified up to homogeneity level by ammonium sulphate and ion-exchange chromatography using a fast protein liquid chromatography (fplc) system. the specific activity of the enzyme increased 4-5 times while the yield was found to be 40.4%. the purification fold by resource-s was recorded to be 3.58. the molecular weight was found to be 55 kda. in the present research work,the vmax (2778 u/mg/min) and km (8.3mg/ml) of α-amylase were derived from the lineweaver burke plot. thermodynamic parameters for soluble starch hydrolysis,ea,δh,δs and δg of α-amylase from b. licheniformis ems-6 were found to be 25.14 kj/mol,22.53 kj/mole,-110.95j/mole/k and 36968 j/mole,respectively. the enzyme was stable over a ph range of 4.5-9.0 and gave ph optimum of 7.0. the pka1 and pka2 of ionizable groups of active site controlling vmax,determined by dixon plot,were 6.0 and 7.5,respectively.