Ipsit Hauli,Bidisha Sarkar, Trinetra Mukherjee and Subhra K. Mukhopadhyay
Amylases are one of the most important enzymes in present-day biotechnology. The objective of this study was to isolate and identify a potential thermophilic amylase producing bacterial strain from hot spring of Bakreswar village, Suri, West Bengal (India). Among the few isolated amylolytic strains on starch agar medium, the strain IB-A showed best amylase activity. Phylogenetic analysis based on 16S rDNA sequence homology shows that the isolated strain belongs to the genus Anoxybacillus, and named as Anoxybacillus sp. IB-A. The optimum temperature and pH for amylase production was found to be 60°C at pH 9.0. Characterization of crude amylase showed its best activity at pH 9.0 and temperature 70°C, with a thermostability of 100% for 10 hours. Enzyme activity was considerably enhanced in the presence of Mo+2, K+, Mn+2, Cu+2 and Co+2. The most significant observation is that the enzyme not only retained cent percent activity in presence of 10 mM Hg+2 and Pb+2 but also increased activity over the control. Among the tested metal ions Zn+2 and Ni+2 showed slight inhibitory effect. The enzyme also showed its high stability and activity in presence of surfactants and chelators, such as SDS, EDTA. So our result showed that the enzyme is highly thermostable, thermo-alkaline and chelator resistant which makes it a suitable candidate for liquefaction of starch at high temperature, in detergent and textile industries. This one is the first report of isolating a potential amylase producing thermophilic Anoxybacillus sp. from hot spring of Bakreswar, West Bengal (India).
