Purification and characterization of extracellular beta-amylase of Bacillus megaterium B(6)

The extracellular beta-amylase from starch induced Bacillus megaterium B6 was purified to homogeneity in a very convenient way; through molecular sieving as demonstrated by the presence of a single band of protein in SDS-PAGE and single peak in gel scanning. The molecular mass of the purified enzyme (monomer) was found to be unusually high, around 105,000 Da. The pH and temperature optima of the purified beta-amylase were at 6.9 and 60 degrees C, respectively. Mn2+ and exogenous thiols were found to play a remarkable role in reactivation of thermally and chemically denatured enzyme. The purified enzyme could saccharify both pure and low quality starches, where maltose could be detected as the major end product.