一株产新型淀粉酶嗜温菌ZW2531-1的分离与鉴定

Isolation and Identification of a Mesophilic Bacteria ZW2531-1 Producing a Novel Amylase

根据淀粉筛选平板上透明圈的大小,从土壤中筛选、分离出12株产淀粉酶嗜温菌株,由各菌株分泌淀粉酶催化淀粉降解的产物组分特征判定,菌株ZW2531-1为初筛12个菌株中较优良的产酶菌株.由ZW2531-1产生的新型淀粉酶可催化淀粉降解产生麦芽糖、麦芽三糖和异麦芽三糖及异麦芽四糖,但不产生葡萄糖.通过电镜观察,可见ZW2531-1菌株的杆菌形态及芽孢.提取ZW2531-1的全基因组,根据已知16S rDNA上的保守序列设计引物,扩增出ZW2531-1菌株的16S rRNA基因,并与其他标准菌16S rDNA序列进行对比分析,建立进化树,最终确定了ZW2531-1的系统发育地位,推断ZW2531-1应属于Bacillus属的一个种,为Bacillus sp.ZW2531-1.

Twelve amylase-producing mesophilic strains, newly isolated from Chinese soil were screened according to their ability of starch digestion by clear zone method. Among them, strain ZW2531-1 showed high amylase-producing ability, and its amylase could catalyze the degradation of starch to produce several oligosc-charities including maltose, maltotriose and a large amount of isomaltotriose and isomaltotetraose, without glucose. Strain ZW2531-1 was bacilliform, a spore forming bacterium under an electron microscope. To explore the phylogenetic position of strain ZW2531-1, its 16S rRNA gene was amplified, sequenced, and then was compared with those of standard bacteria available in Genebank databases. Further, the phylogenetic tree including strain ZW2531-1 was built. All the results regarding strain ZW2531-1 support that bacterium ZW2531-1 belongs to genus Bacillus, therefore, it could be proposed as Bacillus sp.ZW2531-1.