Isolation of thermostable alpha-amylase producing bacterium from thermal springs and partial characterization of the enzyme

In this study, Bacillus sp. strains exhibiting α-amylase activity isolated from the soil samples of the thermal spring those located in the borders of Nigde province, Ulukısla subprovince, Çiftehan region. Isolated bacterium was named as Bacillus sp GA4. Optimum activity temperature, optimum pH value, thermal stability, SDS-PAGE zymogram analysis, antibacterial activitiy and the effect of some chemicals on α-amylase enzyme of Bacillus sp. GA4 were determined. Optimum pH and temperature values of the enzyme were found 6.0-8.0 and 50 ℃ respectively. Enzyme activity was retained totally after pre-incubation within 30 minutes and at 40 ºC. However, enzyme acitivity was reduced at the rate of %21 and %37 after pre-incubation at 50 ºC and 60 ºC, repectively. MgCl2 and FeSO4 inhibited enzyme activity at levels of %13 and %12, whereas CuSO4, CaCl2 and EDTA inhibited %81, %38 and %33 respectively. The molecular weight of Bacillus sp. GA4 α-amylase was found to be approximately 55 kDa by SDS-PAGE zymogram analysis. The isolate was found to be sensitive to CFX, CN, TE, RD, S, Amp and P, while resistant to SH. According to these results, GA4 α-amylase is not suitable for industrial use with its existing properties, but can be made suitable for molecular genetic modifications.