垃圾渗滤液污染地下水中硫酸盐还原菌种群结构多样性分析

实验样本取自上海老港垃圾填埋场两处受垃圾渗滤液和海水双重污染的地下水监测井.通过PCR扩增异化型亚硫酸盐还原酶(Dissimilatory sulfite reductase,DSR)基因,建立dsrAB基因克隆文库,用系统发育分析的方法研究了两口污染程度不同的地下水监测井水样中硫酸盐还原菌(Sulfate-reducing bacteria,SRB)的种群结构.结果表明,Desulfobacter-aceae在两口地下水监测井G和I井中均占主导地位(分别为40.5%和49.0%),在海水混入比例更高、污染程度更重的I井文库中有40.6%类Desulfobacteraceae克隆子具有嗜盐或适盐性,相比较,G井中有31.0%克隆子具有嗜盐或适盐性.实验还发现,I井中次优势菌群是Syntrophobacteraceae(30.9%),而G井中次优势菌群是Desulfobulbaceae(29.8%).表明海水混入比例和污染程度的不同会导致地下水系统中SRB的种群结构差别.研究结果也体现了老港地下水系统特殊的物理化学环境导致了其与国内外其它垃圾填埋场地下水中主要SRB种群的差别.图2表2参18

Diversity and Characterization of Sulfate-reducing Bacteria in Groundwater Polluted by Landfill Leachate and Seawater

The samples for this study were collected from two groundwater monitoring wells of Shanghai Laogang Landfill, where the groundwater was polluted by both leachate and seawater. The diversity of sulfate-reducing bacteria (SRB) was investigated by molecular techniques. After extracting total genomic DNA from the two samples, dissimilatory sulfite reductase (DSR) genes were amplified using specific primers, and then two clone libraries were established. The sequencing and subsequent phylogenetic analysis of the two clone libraries showed that Desulfobacteraceae was the most dominant bacterial clones in Sample G and Sample I (40.5% and 49.0%), and the halophilic characterization of the phylogenic genera was more obvious in Sample I than in Sample G (40.6% and 31.0% ) because of the higher pollution degree and ratio of seawater. The differences in the dominating SRB were found between the Laogang Landfill and other domestic and foreign landfills, which might be affected specially by the leachate and seawater. The result also showed that the second dominant SRB group was Syntrophobacteraceae (30.9%) in Sample I, and Desulfobulbaceae (29.8%) in Sample G. It indicated that the ratio of seawater and the pollution degree could affect the diversity of SRB. Fig 2, Tab 2, Ref 18