Author(s): Arikan B
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Abstract A thermostable alkaline alpha-amylase producing Bacillus sp. A3-15 was isolated from compost samples. There was a slight variation in amylase synthesis within the pH range 6.0 and 12.0 with an optimum pH of 8.5 (8mm zone diameter in agar medium) on starch agar medium. Analyses of the enzyme for molecular mass and amylolytic activity were carried out by starch SDS-PAGE electrophoresis, which revealed two independent bands (86,000 and 60,500 Da). Enzyme synthesis occurred at temperatures between 25 and 65 degrees C with an optimum of 60 degrees C on petri dishes. The partial purification enzyme showed optimum activity at pH 11.0 and 70 degrees C. The enzyme was highly active (95\%) in alkaline range of pH (10.0-11.5), and it was almost completely active up to 100 degrees C with 96\% of the original activity remaining after heat treatment at 100 degrees C for 30 min. Enzyme activity was enhanced in the presence of 5mM CaCl2 (130\%) and inhibition with 5mM by ZnCl2, NaCl, Na-sulphide, EDTA, PMSF (3mM), Urea (8M) and SDS (1\%) was obtained 18\%, 20\%, 36\%, 5\%, 10\%, 80\% and 18\%, respectively. The enzyme was stable approximately 70\% at pH 10.0-11.0 and 60 degrees C for 24h. So our result showed that the enzyme was both, highly thermostable-alkaline, thermophile and chelator resistant. The A3-15 amylase enzyme may be suitable in liquefaction of starch in high temperature, in detergent and textile industries and in other industrial applications.
This article was published in Bioresour Technol
and referenced in Journal of Microbial & Biochemical Technology