产耐热普鲁兰酶菌株的分离、筛选与鉴定

从某火山口的土壤样品中分离筛选得到了一株产耐热普鲁兰酶菌株T-10,酶活力为1.22 U/m L。经形态特征观察、生理生化特征实验以及16S r DNA序列同源性分析,确定该菌株为解淀粉芽孢杆菌。酶学性质研究表明:该普鲁兰酶的最适温度是60℃,在70℃保温4 h后活力残留60%以上;最适p H值为6.0,p H 3.0~8.0在室温保存4 h后相对酶活力大约为70%。目前,鲜有发现产耐热普鲁兰酶的菌株为解淀粉芽孢杆菌,其具备良好的应用前景。

Isolation,Screening and Identification of a Bacterial Strain Producing Thermostable Pullulanase

themostable pullulanase-producing strain, designated as T-10, with enzymatic activity of 1.22 U/mL, was isolated from soil samples collected at a crater field. By applying morphological observation, physiological and biochemical tests and 16S rDNA sequence homology analysis, it was identified as Bacillus amyloliquefacienss. The optimum temperature for the pullulanase activity was 60 ℃ and more than 60% of its maximum activity was maintained after incubation at 70 ℃ for 4 h. The optimum pH value for the pullulanase activity was 6.0, and about 70% of its maximum activity was maintained in the range of 3.0?8.0 after incubation for 4 h. At present, only a few thermostable pullulanase-producing strains of B. amyloliquefaciens are available, and so this new strain of B. amyloliquefaciens has a good application prospect.