Porphyrobacter sp.D22F的降解特性及其在石油降解菌群中的生态位

为揭示多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)降解微生物资源的多样性和石油降解菌群的优势菌,研究了从南海沉积物中分离得到的一株PAHs降解菌D22F的降解特性及其在石油降解菌群D22-1中的生态位.对菌株D22F进行16S rRNA基因同源性分析及透射电镜观察以初步确定其种属,通过培养法、气相色谱质谱联用(GC-MS)测定其多环芳烃降解范围和降解率,通过简并引物PCR扩增其PAHs双加氧酶大亚基基因片段并进行系统发育分析,采用变性梯度凝胶电泳(DGGE)监测石油降解菌群中的优势菌.结果表明,与菌株D22F的16S rRNA基因相似度最高的模式株为产卟啉杆菌属Porphyrobacter tepidarius DSM 10594T(AF465839;98.55%).该菌株能降解萘、甲基萘、苊、硫芴、菲、蒽等;对初始浓度为0.2 g/L菲10 d后的降解率可达90%以上.从其基因组DNA中克隆到的PAHs起始双加氧酶大亚基基因phnAc与Novosphingobium aromaticivorans DSM 12444中的质粒pNL1(CP000676)上的bphA1f基因相似度最高,达到99.41%.DGGE谱图显示,菌株D22F是石油降解菌群中的3种优势菌之一,在传代菌群中可稳定存在.Porphyrobacter sp.D22F为产卟啉杆菌属(Porphyrobacter)中首株以低分子量PAHs为唯一碳源和能源的菌株,是石油降解菌群的优势菌.

Characterization of PAHs-degrading Bacterium Porphyrobacter sp.D22F and Its Ecological Niche in Oil-degrading Consortium D22-1

In order to explore the diversity of microbial resources which could degrade polycyclic aromatic hydrocarbons(PAHs),and dominant species in oil-degrading consortium,the PAHs-degrading capability of strain D22F isolated from the sediment of South China Sea and its ecological niche in the oil-degrading consortium D22-1 were studied.Strain D22F was identified by 16S rRNA gene sequences homology analysis and transmission electron micrograph(TEM).The sphere and rate of PAHs degradation by stain D22F were determined by cultivation experiments and gas chromatography-mass spectrometry(GC-MS),respectively.The phnAc gene encoding the large subunit of PAHs dioxygenase was obtained by PCR amplification with degenerate primers and then analysed phylogenetically.Besides,the dominant species of oil-degrading consortium D22-1 was determined by denatured gradient gel electrophoresis(DGGE) analysis.The results indicated that strain D22F was closely related to type strain Porphyrobacter tepidarius DSM10594T(AF465839),with 98.55% 16S rRNA gene similarity.It could degrade naphthalene,methylnaphthalene,acenaphthene,dibenzothiophene,phenanthrene and anthracene.Strain D22F was used to degrade phenanthrene(0.2 g/L) and the degradation efficiency was above 90% after ten days of incubation.The phnAc gene cloned from genome of strain D22F exhibited 99.41% similarity with the gene bphA1f located on plasmid pNL1(CP000676) of Novosphingobium aromaticivorans DSM12444.Furthermore,DGGE analysis indicated that strain D22F was one of the three dominant species of oil-degrading consortium D22-1 and its abundance kept stable in the sequential subcultures.These research results suggested that strain D22F played an important role in ecological niche of oil-degrading consortium D22-1.