Microbial Degradation of Petroleum Hydrocarbons and PCBs

多氯联苯（PCBs）和石油碳氢化合物（PHs）经常共同污染超级基金场址的水生沉积物。这些复杂和有毒混合物的成分在食物链中生物积累，最终威胁人类健康。多氯联苯和小灵通的微生物降解通常是缓慢的或被环境条件或污染物本身所抑制。事实上，共同污染的小灵通吸收多氯联苯，使它们无法用于微生物脱氯，这是多氯联苯降解和解毒的关键步骤。提出的研究目标是通过首先提高PH生物降解来促进PCB的脱氯。该提案的基本操作假设是厌氧微生物进行的氧化代谢将催化石油的增强降解，这将导致共同污染多氯联苯的还原性脱氯的生物利用度更高。小灵通的好氧生物降解需要引入氧气，这将抑制对氧敏感的PCB脱氯细菌。这就是为什么本研究的重点是小灵通的厌氧生物降解。本研究的具体目标基于以下假设：1)硫酸盐还原作为PH降解的终端电子接受过程（TEAP）将增强微生物PCB脱氯；2)微生物电极还原作为PH降解的终端电子接受过程（TEAP）将增强微生物PCB脱氯。硫酸盐可作为石油厌氧氧化的终端电子受体。微生物电极还原是一种很有前途的新方法

Polychlorinated biphenyls (PCBs) and petroleum hydrocarbons (PHs) frequently co-contaminate aquatic sediments found at Superfund sites. Components of these complex and toxic mixtures bioaccumulate in the food chain eventually threatening human health. Microbial degradation of PCBs and PHs is often slow or inhibited by environmental conditions or the contaminants themselves. In fact, the co-contaminating PHs sorb PCBs leaving them unavailable for microbial dechlorination, a critical step in the degradation and detoxification of PCBs. The goal of the proposed research is to promote PCB dechlorination by first enhancing PH biodegradation. The Underlying Operative Hypothesis of this proposal is that oxidative metabolism performed by anaerobic microorganisms will catalyze enhanced degradation of petroleum, which will result in greater bioavailability of co-contaminating PCBs for reductive dechlorination. Aerobic biodegradation of PHs would require the introduction of oxygen, which would inhibit the oxygen sensitive PCB dechlorinating bacteria. That is why this investigation is focused on the anaerobic biodegradation of the PHs. The Specific Aims for the research are driven by the following hypotheses: 1) sulfate reduction as the terminal electron accepting process (TEAP) for PH degradation will result in enhanced microbial PCB dechlorination, and 2) microbial electrode reduction as the TEAP for PH degradation will result in enhanced microbial PCB dechlorination. Sulfate can serve as a terminal electron acceptor for the anaerobic oxidation of petroleum. Microbial electrode reduction is a new and promising method that can be coupled to the degradation of organic matter and does not require the active addition of a terminal electron acceptor such as oxygen or sulfate. The PIs intend to use innovative comprehensive two-dimensional gas chromatography (GCxGC/MS) to examine the complex mixtures of PCBs and PHs. This method enables researchers to analyze components of petroleum previously not resolvable. The microbial communities will be examined with recently developed PCR based molecular technologies. This study will be the first comprehensive investigation on the anaerobic degradation of PCBs and petroleum coupled to sulfate or novel electrode reduction. It is predicted that this innovative research will lead to the development of new technologies for the co-bioremediation of PCBs and petroleum.