BIOCHEMICAL APPROACHES OF INCREASING THERMOSTABILITY OF BETA-AMYLASE FROM BACILLUS-MEGATERIUM B-6

Studies on the irreversible thermoinactivation of beta-amylase from Bacillus megaterium B-6 exposed to 60 degrees C revealed that the deactivation mechanism probably results from the oxidation of thiols present at the active site of the enzyme. Several attempts were made to increase its thermostability, which indicated that Mn2+ played a key role in determining thermostability and partially reactivating the inactivated enzyme. Immobilization of beta-amylase through gel-entrapment and covalent crosslinking brought about a remarkable increase in thermotolerance with about a 14-fold increase in catalytic half-life.