Bedard Donna L, Bailey Jessica J, Reiss Brandon L, Jerzak Greta Van Slyke
Department of Biology, SC 1W14, Rensselaer Polytechnic Institute, 110 8th St., Troy, NY 12180, USA.
Appl Environ Microbiol. 2006 Apr;72(4):2460-70. doi: 10.1128/AEM.72.4.2460-2470.2006.
We have developed sediment-free anaerobic enrichment cultures that dechlorinate a broad spectrum of highly chlorinated polychlorinated biphenyls (PCBs). The cultures were developed from Aroclor 1260-contaminated sediment from the Housatonic River in Lenox, MA. Sediment slurries were primed with 2,6-dibromobiphenyl to stimulate Process N dechlorination (primarily meta dechlorination), and sediment was gradually removed by successive transfers (10%) to minimal medium. The cultures grow on pyruvate, butyrate, or acetate plus H(2). Gas chromatography-electron capture detector analysis demonstrated that the cultures extensively dechlorinate 50 to 500 mug/ml of Aroclor 1260 at 22 to 24 degrees C by Dechlorination Process N. Triplicate cultures of the eighth transfer without sediment dechlorinated 76% of the hexa- through nonachlorobiphenyls in Aroclor 1260 (250 mug/ml) to tri- through pentachlorobiphenyls in 110 days. At least 64 PCB congeners, all of which are chlorinated on both rings and 47 of which have six or more chlorines, were substrates for this dechlorination. To characterize the bacterial diversity in the enrichments, we used eubacterial primers to amplify and clone 16S rRNA genes from DNA extracted from cultures grown on acetate plus H(2). Restriction fragment length polymorphism analysis of 107 clones demonstrated the presence of Thauera-like Betaproteobacteria, Geobacter-like Deltaproteobacteria, Pseudomonas species, various Clostridiales, Bacteroidetes, Dehalococcoides of the Chloroflexi group, and unclassified Eubacteria. Our development of highly enriched, robust, stable, sediment-free cultures that extensively dechlorinate a highly chlorinated commercial PCB mixture is a major and unprecedented breakthrough in the field. It will enable intensive study of the organisms and genes responsible for a major PCB dechlorination process that occurs in the environment and could also lead to effective remediation applications.
我们已经开发出无沉积物的厌氧富集培养物，其能够对多种高氯多氯联苯（PCBs）进行脱氯。这些培养物是从马萨诸塞州莱诺克斯市胡萨托尼克河受Aroclor 1260污染的沉积物中培养出来的。用2,6-二溴联苯引发沉积物浆液，以刺激N过程脱氯（主要是间位脱氯），并通过连续转移（10%）将沉积物逐渐转移到基本培养基中，从而将其去除。这些培养物以丙酮酸、丁酸盐或乙酸盐加H₂为生长底物。气相色谱 - 电子捕获检测器分析表明，这些培养物在22至24摄氏度下通过N脱氯过程对50至500微克/毫升的Aroclor 1260进行大量脱氯。第八次转移且无沉积物的三份重复培养物在110天内将Aroclor 1260（250微克/毫升）中六氯至九氯联苯的76%脱氯为三氯至五氯联苯。至少64种多氯联苯同系物是这种脱氯的底物，所有这些同系物在两个环上都有氯取代，其中47种有六个或更多氯原子。为了表征富集培养物中的细菌多样性，我们使用真细菌引物从在乙酸盐加H₂上生长的培养物中提取的DNA扩增并克隆16S rRNA基因。对107个克隆进行的限制性片段长度多态性分析表明，存在类Thauera的β-变形菌、类地杆菌的δ-变形菌、假单胞菌属、各种梭菌目、拟杆菌门、绿弯菌门的脱卤球菌属以及未分类的真细菌。我们开发出高度富集、健壮、稳定且无沉积物的培养物，其能对高度氯化的商业多氯联苯混合物进行大量脱氯，这是该领域一项重大且前所未有的突破。它将能够深入研究环境中主要多氯联苯脱氯过程所涉及的生物体和基因，也可能带来有效的修复应用。
