Detergent Stable, Halotolerant Α-amylase from Bacillus Aquimaris Vitp4 Exhibits Reversible Unfolding

Halotolerant Bacillus aquimaris VITP4, isolated from Kumta coast (India), was used to produce extracellular α-amylase. The production was found to be maximal after 24 h of growth at pH 8.0 and 40 C. Optimal activity of the purified enzyme was in the pH range of 7.5 – 9.5 at 40 C. The enzyme was found to retain more than 60% of the initial activity even at NaCl concentration of 3.5 M, indicating that it is halotolerant. Calcium ion (0.01 mM) and CTAB (10 mM) enhanced the activity whereas EDTA decreased the enzymatic activity. Thermal inactivation kinetics suggested that the enzyme exhibits reversible unfolding even at high temperature (till 90 C) and the t1/2 at 90 C was found to be 43.5 min. These results suggests that the α-amylase from Bacillus aquimaris strain VITP4 is halotolerant, metal ion dependent enzyme which is stable in the presence of cationic detergent and moderate temperature conditions.