Biochemical characterization of heat- and acid-resistant mutant ofBacillus licheniformis α-amylase
LIU Xuelian1, SHEN Peili2, NIU Dandan1, JIN Peng1, TIAN Kangming1, WANG Zhengxiang1*
1 (College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, Tianjin 300457, China) 2 (College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China)
Abstract: The heat- and acid-resistance of Bacillus licheniformis α-amylase (BLA) is the most important application property for enzymatic processing of starch. In this study, biochemical properties of mutant V-2 obtained by artificial evolution were comprehensively analyzed. V-2 showed the highest enzyme activity at 80℃ and pH 5.5, which was 10 ℃ higher and 0.5-1.0 pH lower than that of BLA, respectively. Its heat and acid resistance were significantly improved. The effects of metal ions, especially Ca2+, on the activity of V-2 were significantly reduced. V-2 was significantly more efficient than BLA in starch hydrolysis, with its catalytic efficiency 33 folds higher than that of BLA.
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