Production and characterization of thermostable α-amylase from thermophilic anoxybacillus flavithermus sp. nov. SO-19.

Abstract

This study was concerned with isolation and identification of thermophilic bacteria from hot spring in Afyonkarahisar (Gecek) and optimization of a-amylase production, partial purification of a-amylase, and characterization of extracellular enzyme from isolated thermophilic strain 19. To characterize and identify the thermophilic isolated bacteria, morphological analysis and biochemistry tests were studied. Besides, for classification 16S rRNA gene, G–C content and DNA–DNA hybridization analysis were performed. These results indicated that strain 19 is a novel species, Anoxybacillus flavithermus sp. nov. The effects of different fermentation conditions, such as incubation time, temperature, and pH, different carbon and nitrogen sources, and surfactants on a-amylase production were investigated. Various parameters such as temperature and temperature stability, pHand pH stability, detergents and surfactants, different starches, and metal ions on influence of enzyme characterization were assayed. About 93, 87, and 81% of the activities were retained after heating the partially purified enzyme solution at 50, 60, and 70 for 240 min, respectively. Enzyme was excessively inhibited by Hg (6%). The enzyme was activated by Co (212%) and Mg (142%). Enzyme degradated 82% of starch content in apple juice at70°C in 30 min. The molecular weight of enzyme was estimated as 96 kDa.