MICROBIAL DEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBON MIXTURES

许多环境都暴露在多环芳烃（PAHs）中 和N-杂环芳族化合物（NHAs）作为复杂混合物。 具体地说， 3000煤气化厂旧址构成重大健康 隐患 研究将建立在以下方面取得的进展之上： 土壤微生物和微生物群落的分离， 降解聚芳族化合物及其混合物，B） 代谢中间体的表征 已知的文化，新的分离物和财团c）土壤的影响 成分对这些化合物的生物利用度和吸附的影响，以及 d）这些化合物的遗传毒性作用。 这项建议的目标是 柠檬酸，致癌4和5环多环烃（PAHs） 以及同样重要的N-杂环芳烃（NHA）。 我们的整体 目的是确定和提高微生物降解率的 在模拟环境条件下， 与PAH和NHA生物降解相关的潜在健康危害 产品. 目标是改善生物降解和矿化 用于消除聚芳族化合物及其代谢物， 污染的土壤。 具体目的：1）分离降解微生物， 多环多环芳烃和NHAs的气化网站正在研究使用模拟 浓缩技术 化合物包括对BaP的进一步研究， 苯并（a）蒽、二苯并（c，g）咔唑、二苯并（a，j）吖啶和新 与四环吖啶和咔唑的倡议 衍生物. 2)使用2、3和4环化合物的分离降解剂 单独，混合物以及污染土壤中。 代谢 中间体，环裂解和反应序列将进行研究 使用分离物和纯培养物。 利用藻类和细菌的研究 以共代谢的方式降解大环多环芳烃， 进行。 3)确定致癌金属对 通过分离的2，3和4环降解菌对多环芳烃的降解。 四、 确定2、3和4环降解产物进一步分离的程度 降解稳定的生物降解产物和光氧化产物， 模拟暴露前条件的孵育物中的PAH/NHA。 5)试验 生物降解和光氧化稳定中间体的能力 在增殖的人淋巴细胞中诱导细胞遗传损伤， 通过诱导微核。 6)检查的健康益处 生物降解 这将涉及确定诱变活性 土壤有机提取物中PAH的含量 代谢物混合物和单个降解产物。 与 了解微生物碳氢化合物降解过程， 将制定利用微生物碳氢化合物的战略 去除有毒和致癌多环芳烃的降解活性， 来自受污染生态系统的NHAs及其中间体。

Many environments are exposed to polycyclic aromatic hydrocarbons (PAHs) and N-heterocyclic aromatics (NHAs) as complex mixtures. Specifically, 3000 former sites of coal gasification plants constitute major health hazards. The research will build upon the progress made in a) the isolation of soil microorganisms and consortia of microorganisms that degrade polyaromatic compounds and mixtures thereof, b) the characterization of the metabolic intermediates that are produced by known cultures, new isolates and consortia c) the effects of soil constituents on the bioavailability and sorption of these compounds, and d) the genotoxic effects of these compounds. This proposal targets the recalcitrant, carcinogenic 4 and 5 ring polycyclic hydrocarbons (PAHs) and the equally important N-heterocyclic aromatics (NHA). Our overall objective is to determine and enhance the microbial degradation rates of polyaromatics under simulated environmental conditions and to decrease potential health hazards associated with the PAH and NHA biodegradation products. The goal is to improve upon biodegradation and mineralization for the elimination of polyaromatic compounds and their metabolites from polluted soils. The specific aims: 1) Isolate organisms that degrade the multi-ring PAHs and NHAs from gasification sites under study using analog enrichment techniques. Compounds include further studies with BaP, benz(a)anthracene, dibenzo(c,g)carbazole, dibenz(a,j)acridine and new initiatives with chrysene and four ring acridine and carbazole derivatives. 2) Use isolated degraders of 2, 3 and 4 ring compounds singly, in mixtures as well as in contaminated soils. Metabolic intermediates, ring cleavage and reaction sequences will be investigated using both isolates and pure cultures. Studies using algae and bacteria in a cometabolic fashion to degrade large ring PAHs will also be undertaken. 3) Determine the impact of carcinogenic metals on the biodegradation of PAHs by isolated 2, 3 and 4 ring degraders. 4) Determine the extent that 2, 3, and 4 ring degrader isolates further degrade stable biodegradation products, and photooxidized products, of PAH/NHA in incubations that mimic preexposure conditions. 5) Test for the capacity of stable intermediates of biodegradation and photooxidation to induce cytogenic damage in proliferating human lymphocytes as measured by induction of micronuclei. 6) Examine the health benefit of biodegradation. This will involve determining the mutagenic activities of soil organic extracts before and after reintroduction of PAH metabolite mixtures and individual degradation products. With an understanding of the microbial hydrocarbon degradation process, strategies will be developed for utilizing microbial hydrocarbon degrading activities for the removal of toxic and carcinogenic PAHs and NHAs and their intermediates from contaminated ecosystems.