Isolation of α-amylase producing thermophilic Bacillus strains and partial characterization of the enzymes

In the present study, three thermophilic Bacillus strains were isolated from the soil samples collected from the coast sediments of the Burnaz Stream located in Erzin. The isolates were entitled as Bacillus sp. CT1, CT2, and CT3, respectively. The maximum α-amylase production was revealed at 60°C for CT1 strain, and at 80°C for CT2 and CT3 strains, respectively. The optimum enzyme activity was observed at 90°C for CT1 α-amylase, where as at 60°C for CT2 and CT3 α-amylases. On the other hand, optimum pH value for CT2 α-amylase was 7.0, where as 8.0 for CT1 and CT3 α-amylases. The specific activities of CT1, CT2, and CT3 bacterial amylases were 317.6, 113.3 and 362.7 U/mg at 55°C, respectively. The estimated molecular weight of CT1 and CT3 α-amylase was 65 kDa, and for CT2 α-amylase was 38 kDa by zymogram analysis.