【摘 要】
：
In order to obtain pure enzyme with high activity, two amylase producing strains were isolated from soil samples, and named as the strains LZ-10 and LZ-11. According to morphologic observation, physiology and biochemistry experiments, 16S rRNA and gyrB ge
【机 构】
：
Foundation Experiment Teaching Center,Gansu Agricultural University,Lanzhou 730070,China;College of
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In order to obtain pure enzyme with high activity, two amylase producing strains were isolated from soil samples, and named as the strains LZ-10 and LZ-11. According to morphologic observation, physiology and biochemistry experiments, 16S rRNA and gyrB gene analysis, the strains LZ-10 and LZ-11 were identified as Bacillus subtilis. Adopted the method of ammonium sulfate, DEAE-52 anion purify enzyme, finally used polyacrylamide gel electrophoresis (SDS-PAGE) to detect molecular weight. The strain LZ-10 had an amylase activity of 123.3 U ? mL-1, a purification factor of 6.8, a recovery rate of 69.5％ and an optimal temperature of 50℃. The amylase activity of the strain LZ-11 was 59.91 U ? mL-1, the purification factor was 4.5, the recovery rate was 60.5％, and the optimum temperature was 55℃. The commodity enzyme derived from Bacillus subtilis was 37.5 U ? mL-1. The relative molecular weight of amylase activity from the two strains was 55 ku. Both thermal stability and pH stability were higher than those of commercialized amylase.
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