SOLUBLE EXPRESSION OF BACILLUS LICHENIFORMIS ATCC 27811 alpha-AMYLASE AND CHARACHTERIZATION OF PURIFIED RECOMBINANT ENZYME

Alpha amylase (alpha-amylase) from Bacillus licheniformis shows great role in starch hydrolysis for industrial application due to its thermostability, long half-life and specificity. However, it is difficult to produce this enzyme in large quantities because of formation of inclusion bodies, but lowering the temperature to 18 degrees C leads to a soluble expression of protein. This also highlighted the efficacy of Escherichia coli as one of the best host for secretion of recombinant proteins. A further study to find an approach for a soluble expression of alpha-amylase was conducted here, using pET-22b(+) as an expression vector and temperature optimization. Purified monomeric enzyme displayed a specific activity of 584.61 U/mg at 37 degrees C and a molecular mass of 52 kDa. Purification fold of recombinant alpha-amylase was 2.04 times in comparison to crude amylase extract. Relative activity of enzyme was remarkably enhanced by Ca+2 but strongly impeded by Cu2+ and Na+1, highlighted the significance of Ca+2 as a cofactor for optimal amylase activity.