一株高温菌所产酶的功能分析与菌株分类鉴定

从长白山温泉中分离出一株可产生淀粉降解酶的高温菌(CW₂)， 用薄层层析法分析鉴定酶促淀粉降解的产物， 发现CW₂所产生的淀粉降解酶系胞外酶， 可催化淀粉降解产生异麦芽低聚糖(主要包括异麦芽糖、 异麦芽三糖和潘糖). 用PCR法扩增其16S rDNA， 测定其序列（873 bp）， 与GeneBank中已知菌的16S rDNA序列对 比， 该菌株与模式菌株Bacillus licheniformis ATCC 14580，Bacillus licheniformis  DSM 13,Bacillus subtilis strain JM4的16S rDNA序列同源性最高， 只分别相差9,9,13个碱基， 序列相似性分别为98.97％,98.97％,98.51％. 用Neighbor joining方法构建CW₂进化树， 并用Bootstraping法对其评估， 结果表明， CW₂与Bacillus licheniformis， Bacillus sonorensiss形成Bacillus属中的亲缘关系最近的一个进化种群.

An Enzyme from a Thermophilic Bacteria and the Identification of the Strain

A thermophilic strain CW_2,which can produce a type of starch-degrading enzyme,was isolated from the soil around a hot spring in the Changbai Mountains.The products from starch by the enzyme were determined by thin layer chromatography(TLC) and the results show that the enzyme is a kind of ectoenzyme that could catalyze the degradation of starch to produce isomaltooligosaccharide including isomaltose,isomaltotriose,and panose as dominant products.The 16S rDNA of the strain was amplified by PCR and was sequenced (873 bp),and then was compared with those available in the GenBank databases.The result shows that(CW_2) 16S rDNA sequence is most similar to that of Bacillus licheniformis ATCC(14580,) Bacillus licheniformis DSM 13 and Bacillus subtilis strain JM4, there are only 9,9,13 different bases between every pair of sequences,the sequence similarities are(98.97%,)(98.97%,)(98.51%,) respectively.The phylogenetic trees including CW_2 were derived with neighbor joining and analyzed with Bootstraping.The results demonstrate that CW_2 strain is close consanguinity to Bacillus licheniformis and Bacillus sonorensiss, they belong to the same sister cluster in Bacillus group.