石油污染地下水中细菌分子生态学研究

Bacterial molecular ecology in the groundwater contaminated by oil

采集了某废弃炼油厂的石油污染地下水样品,提取水中微生物总DNA,构建细菌16SrDNA克隆文库,并通过16SrDNA序列的系统发育分析,对样品中的细菌种群多样性以及群落结构进行了研究。结果表明,文库中阳性克隆的16S rDNA序列分属11个细菌类群,分别为Betaproteobacteria(38.1%),Alphaproteobacteria(35.3%),Gamaproteobacteria(5.1%),Deltaroteobacteria(5.2%),Bacteroidetes(4.0%),Verru-comicrobia(2.5%),Epsilonproteobacteria(1.9%),Nitrospira(1.3%),Planctomycetes(1.3%),Candidate Di-vision OD1(1.3%),Unclassified Bacteria(3.8%)。在这一生态系统中,Betaproteobacteria和Alphapro-teobacteria类细菌占据主导地位,二者所占比例均在三分之一以上。群落中最主要的降解菌是噬氢菌属(Hydrogenophaga)和鞘氨醇单胞菌属(Sphingomonas)细菌,它们在文库中所占比例达23.9%和19.5%。该石油污染地下水样品中细菌与许多其他已知的降解菌亲缘关系较近,如Sulfuricurvumkujiense、Trichlo-robacterthiogenes、Rhodoferax ferrireducens以及红细菌属(Rhodobacter)、甲基单胞菌属(Methylomonas)和涅瓦菌属(Nevskia)细菌等。此外,文库中克隆的16S rDNA序列与许多类似的污染场地中发现的环境克隆相似性很高,如煤焦油污染的地下水、苯污染的地下水、原油污染的土壤、溴甲烷和氯甲烷污染的土壤、抗生素生产废水以及活性污泥等,证明该石油污染地下水中有大量降解菌群的存在。石油污染物的种类对降解菌群的组成有一定的选择作用。

An oil-contaminated groundwater sample was collected at an abandoned petrochemical factory. Bacterial genome DNA was extracted for the 16S rDNA gene amplification, and then a bacterial 16S rDNA gene clone library was constructed. After the phylogenetic analysis of 16S rDNA sequences, bacterial diversity and community structure of the groundwater were studied. The results showed the bacteria in the groundwater could be divided into 11 groups, which were as follows.. Betaproteobacteria （ 38. 1 %）, Alphaproteobacteria （35.3 %）, Garna proteobacteria （ 5.1% ）, Deltaroteobacteria （ 5.2 % ）, Bacteroidetes （ 4.0 % ）, Verrucomicrobia （2.5 % ）, E psilon proteobacteria （ 1.9 %）, Nitros pira （ 1.3 % ）, P lanctomycetes （ 1.3 % ）, Candidate Division OD1 （ 1.3 % ）, Unclassified Bacteria（3.8 % ）. Betaproteobacteria and Alphaproteobacteria were predominant in the ecosystem, each of which accounted for over one-third of total clones. Hydrogenophaga and Sphingomonas are the most abundant degrading bacteria in the sample, which accounted for 38.1 % and 35.3% of all bacteria respectively. Many clones also affiliated with other degrading bacteria, such as Sulfuricurvum kujiense, Trichlorobacter thiogenes, Rhodoferax ferrireducens and bacteria of genus Rhodobacter, Methylornonas, Nevskia. Besides, a lot of 16S rDNA sequences in the clone library had high similarity to the ones originated from similar polluted environments, such as groundwater contaminated with tar oil, groundwater contaminated with benzene, soil contaminated with crude oil, soil contaminated with methyl bromide and methyl chloride, antibiotics production wastewater and activated sludge, which proved that there were lots of degrading bacteria population in the oil-contaminated water. The components of petroleum contaminant have an important effect on community structure of degrading bacteria.