Subhas Chandra Jana

Biochemical approaches of increasing thermostability of β‐amylase from Bacillus megaterium B6

Studies on the irreversible thermoinactivation of β‐amylase from Bacillus megaterium B6 exposed to 60°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 β‐amylase through gel‐entrapment and covalent crosslinking brought about a remarkable increase in thermotolerance with about a 14‐fold increase in catalytic half‐life.

β-Amylase fromBacillus megaterium

Bacillus megaterium strain B6 producing extracellular β-amylase was isolated and grown in a medium supplemented with waste potato starch. It showed highest enzyme synthesis in the early stationary phase. The partially purified β-amylase had a temperature optimum at 60°C and a pH optimum at 6.9 and was not affected by Schardinger dextrins. These properties would allow its application in sugar industry.

Adsorption of β‐amylase from Bacillus carotarum B6 onto different native starches

β‐Amylase from Bacillus carotarum B6, a soil isolate, was readily adsorbed onto native raw starch from various sources. The absorbability was highest toward arrowroot starch and was complete within 30 min of exposure. Adsorption was remarkably affected in the presence of surfactants like Tween 80.