一株海洋新鞘氨醇杆菌phe-8(Novosphingobium sp.)的PAHs降解基因和降解特性

Characterization of a PAHs Degrading Marine Strain Novosphingobium sp.Phe-8 and Its Degradative Genes

以菲为唯一碳源和能源从厦门近海海水样品中筛选到一株能够降解多种PAHs的细菌.16S rDNA序列同源性分析表明它可能属于新鞘氨醇杆菌属(Novosphingobiumsp.).根据已经报道的PAHs起始双加氧酶大亚基基因序列,设计了一对简并引物,并PCR扩增得到了约700 bp的基因片段.比对结果显示它同已报导的一株降解菌Novosphingobium ar-omaticivoransF199质粒上的bphA1 f基因相似度最高,达到98.26%,该基因编码的蛋白推断是萘或联苯双加氧酶大亚基.以PCR产物为模板制备DNA探针,Southern杂交表明:该基因位于其质粒DNA上.采用气相色谱-质谱联用测定了该菌的降解率,发现它可以高效降解多种高分子量PAHs.

A PAHs-degrading strain, with phenanthrene as sole carbon and energy source, was isolated from sea water sample of Xiamen ferry dock. 16S rDNA sequences similarity analysis indicated that it was a strain of genus Novosphingobium, tentatively named Novosphingobium sp. phe-8. A pair of degenerate primers were designed according to published PAHs initial dioxygenase α-subuait gene sequences and a target gene fragment of about 700 bp was obtained through PCR. And sequence alignment revealed that it was similar to the bphAlf gene of Novosphingobium aromaticivorans F199, which encoded a putative naphthalene or biphenol dioxygenase α-subunit. The PCR-generated partial gene was labeled by digoxin and was used to probe the plasmid DNA of phe-8 in order to locate the degradative gene by Southern blotting. And the result showed that it was located on a plamid. The degrading efficiency of several high-molecular-mass PAHs by phe-8 was determined by GC-MS.