Microbial Degradation of Petroleum Hydrocarbons and PCBs

在超级基金所在地发现的多氯联苯和石油碳氢化合物(PHS)经常共同污染水生沉积物。这些复杂而有毒的混合物的成分在食物链中生物积累，最终威胁到人类健康。微生物对多氯联苯和小灵通的降解往往很慢，或者受到环境条件或污染物本身的抑制。事实上，共同污染的小灵通会吸附多氯联苯，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一步。拟议研究的目标是通过首先加强PH的生物降解来促进多氯联苯的脱氯。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强化降解，这将导致共污染的多氯联苯更大的生物利用度，用于还原脱氯。PHS的好氧生物降解需要引入氧气，这将抑制对氧敏感的多氯联苯脱氯细菌。这就是为什么本研究的重点是小灵通的厌氧生物降解。这项研究的具体目的是由以下假设驱动的：1)作为PH降解的末端电子接受过程(TEAP)的硫酸盐还原将导致提高微生物对多氯联苯的脱氯；2)微生物电极的还原(作为PH降解的TEAP将导致增强的微生物多氯联苯的脱氯)。硫酸盐可以作为石油厌氧氧化的末端电子受体。微生物电极还原是一种新的、很有前途的方法，它可以与 降解有机物，不需要氧或硫酸盐等末端电子受体的活性添加。PIS打算使用创新的全面二维气相色谱(GCxGC/MS)来检测多氯联苯和小灵通的复杂混合物。这种方法使研究人员能够分析以前无法解析的石油成分。微生物群落将用最近开发的基于聚合酶链式反应的分子技术进行检测。这项研究将是首次在硫酸盐或新型电极还原条件下对多氯联苯和石油的厌氧降解进行全面的研究。据预测，这项创新研究将导致开发多氯联苯和石油联合生物修复的新技术。

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.