Screening,Identification and Characterization of An α-amylase-Producing Bacillus subtilis XL-15

Objective: Screening of α-amylase-producing strain was undertaken to provide new strains for the produce of α-amylase in industry.Methods: α-amylase-producing strains were isolated from soil samples by initial screening with iodine solution and the flasks fermentation.Then strains were identified based on partial 16S rDNA gene sequence aligned with the GenBank database and its morphological characteristics.The properties of α-amylase of the strain were examined after ammonium sulfate fraction and dialysis for desalting.Results: An α-amylase-producing strain was isolated and identified as Bacillus subtilis XL-15.The results showed that the optimum temperature and pH of the enzyme were 50℃ and 6.5 respectively,the enzyme activity was obviously inhibited by Cu(2+),Zn(2+) and EDTA.While stimulated by Ca(2+) and Mn(2+),its Km was 1.726mg/mL.Conclusion: This study provided a good experimental material for the further studies on α-amylase.