Three stages of a biofilm community developing at the liquid-liquid interface between polychlorinated biphenyls and water
Three stages of a biofilm community developing at the liquid-liquid interface between polychlorinated biphenyls and water
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DOI：
10.1128/aem.71.11.7301-7309.2005
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发表时间：
2005-11-01
影响因子：
4.4
通讯作者：
Abraham, WR
中科院分区：
文献类型：
--
作者：
Macedo, AJ;Kuhlicke, U;Abraham, WR
以多氯联苯（PCB）污染的土壤为接种物，在多氯联苯油（Aroclor 1242）上构建复合生物膜群落。生物膜进行了监测31天，共聚焦激光扫描显微镜，社区指纹使用单链构象多态性（SSCP），16 S rRNA基因的扩增子，和化学分析的PCB同系物。年轻的生物膜的SSCP分析揭示了一个相当多样化的微生物群落的属Herbaspirillum和Bradyrhizobium作为优势成员的物种。在PCB液滴上发展的生物膜显示了PCB降解和生物膜发展的明显阶段，而在纯培养实验中没有描述过。第一步是在多氯联苯油几乎没有被污染的情况下，在底层定居。当Permanox上的细菌达到一定密度时，PCB被定殖，但很快同源物的降解明显减少，许多细胞被破坏，如活/死染色所示。最后，生物膜形成聚集体并侵入PCB油，显示出比以前更少的受损细胞数量和PCB降解的急剧增加。生物膜形成的这一顺序被理解为在PCB油定植之前的成熟过程。随后是PCB液滴上的薄生物膜，在PCB中形成口袋的聚集过程，以及最后生物膜侵入PCB油中。只有成熟的生物膜显示五氯多氯联苯同系物的降解，这可能是还原脱氯和产生的三氯联苯，然后有氧代谢。
Soil contaminated with polychlorinated biphenyls (PCB) was used as an inoculum to grow a complex biofilm community on PCB oil (Aroclor 1242) on a substratum (Permanox). The biofilm was monitored for 31 days by confocal laser scanning microscopy, community fingerprinting using single-strand conformational polymorphism (SSCP), amplicons of the 16S rRNA genes, and chemical analyses of the PCB congeners. SSCP analysis of the young biofilm revealed a rather diverse microbial community with species of the genera Herbaspirillum and Bradyrhizobium as dominant members. The biofilm developing on the PCB droplets displayed pronounced stages of PCB degradation and biofilm development not described before from pure-culture experiments. The first step was the colonization of the substratum while the PCB oil was hardly populated. When a certain density of bacteria was reached on the Permanox, the PCB was colonized, but soon the degradation of the congeners was markedly reduced and many cells were damaged, as seen by LIVE/DEAD staining. Finally, the biofilm formed aggregates and invaded the PCB oil, showing lower numbers of damaged cells than before and a dramatic increase in PCB degradation. This sequence of biofilm formation is understood as a maturation process prior to PCB oil colonization. This is followed by a thin biofilm on the PCB droplet, an aggregation process forming pockets in the PCB, and finally an invasion of the biofilm into the PCB oil. Only the mature biofilm showed degradation of pentachlorinated PCB congeners, which may be reductively dechlorinated and the resulting trichlorobiphenyls then aerobically metabolized.