Microbial Degradation of Petroleum Hydrocarbons and PCBs

多氯联苯（PCBs）和石油碳氢化合物（PHs）经常共同污染在超级基金站点发现的水生沉积物。这些复杂有毒混合物的成分在食物链中生物累积，最终威胁人类健康。多氯联苯和多氯联苯的微生物降解通常很慢，或受到环境条件或污染物本身的抑制。事实上，共同污染的PH吸附多氯联苯，使其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。建议的研究的目标是促进多氯联苯脱氯，首先提高pH值的生物降解。这一提议的基本操作假设是，厌氧微生物进行的氧化代谢将催化石油的降解，这将导致共同污染的多氯联苯的还原脱氯的更大的生物利用度。PHs的好氧生物降解需要引入氧气，这将抑制氧敏感的PCB脱氯细菌。这就是为什么本研究的重点是厌氧生物降解的PHs。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），将增强多氯联苯的微生物脱氯作用; 2）微生物电极还原作为PH降解的TEAP，将增强多氯联苯的微生物脱氯作用。硫酸盐可作为石油厌氧氧化的末端电子受体。微生物电极还原法是一种新的、有前途的方法， 这是因为它可以降解有机物质，并且不需要主动添加末端电子受体如氧或硫酸盐。PI打算使用创新的全面二维气相色谱法（GCxGC/MS）来检查多氯联苯和多氯联苯的复杂混合物。这种方法使研究人员能够分析以前无法分解的石油成分。微生物群落将采用最近开发的基于PCR的分子技术进行检查。本研究将是第一个全面的调查厌氧降解多氯联苯和石油耦合硫酸盐或新型电极还原。据预测，这一创新性的研究将导致多氯联苯和石油的共同生物修复的新技术的发展。

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.