BACTERIAL DEGRADATION AND INTERACTIONS OF POLYNUCLEAR AROMATIC HYDROCARBONS

多核芳烃的细菌降解和相互作用

• 批准号: 6106334
• 负责人: MICHAEL AITKEN
• 金额: $ 24.56万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6106334
• 关键词: biotransformation; carbopolycyclic compound; mass spectrometry; microorganism metabolism; molecular polarity; soil microbiology; soil pollution; soil sampling; surfactant; toxin metabolism

Polycyclic aromatic hydrocarbons (PAH) are major contaminants in soil and groundwater at a number of sites across the United States. Many of them are known or suspected carcinogens, yet many are also known to be biodegradable by bacteria and fungi indigenous to native and contaminated soils. Biological processes have been used to remediate PAH contaminated soils, but removal of the high molecular weight (HMW), carcinogenic species is often incomplete. Far less is known about the biodegradation of HMW PAH (defined as those with four or more rings) than is known about the degradation of two- and three ring compounds. Some bacteria recently have been found to grow on four-ring PAH, while others only cometabolize these compounds. The purposes of this project are to study the metabolism and biodegradation of HMW PAH, with particular emphasis on identifying products of incomplete metabolism that may accumulate in the aqueous phase; to study the kinetics of HMW PAH degradation; to asses the influence of other PAH on the rate of HMW PAH degradation when present in mixtures; to evaluate potential inducers of HMW PAH metabolism which might be used to sustain the growth of bacteria that cometabolize HMW PAH after their principal growth substrates are depleted; to evaluate the influence of mass transfer processes on the rate and extent of HMW PAH degradation; and to evaluate strategies to increase the extent of HMW PAH degradation in mass transfer-limited situations. These aims will be met using PAH degrading bacteria already isolated from a variety of contaminated soils and which appear to contain different pathways for PAH metabolism/ some of these bacteria also have characteristics which may allow them to influence mass transfer processes. These bacteria will be screened for evidence of metabolite production using spectroscopic methods and mass balances with radiolabeled substrates. Analysis of metabolites will employ evolving techniques in mass spectrometry to aid in the identification of polar, non-volatile compounds. Mass transfer processes of interest include dissolution of PAH from non- aqueous phases and desorption from soil organic matter. Quantitative models will be developed to ascertain that biodegradation can be quantified using independently measured rate parameters, and as a tool in identifying those organisms that may influence mass transfer processes. Strategies to improve the biodegradability of HMW PAH will pounds as growth substrates and the use of nonionic surfactants to increase the bioavailability of these compounds.

多环芳烃（PAH）是土壤和环境中的主要污染物 美国许多地点的地下水。 他们中的许多人 是已知或可疑的致癌物，但许多也被认为是 可被原生和受污染的细菌和真菌生物降解 土壤。 生物过程已用于修复 PAH 污染 土壤，但去除高分子量 (HMW) 致癌物质 往往是不完整的。 人们对高分子量多环芳烃的生物降解知之甚少 （定义为具有四个或更多环的环）比已知的 二环和三环化合物的降解。 一些细菌最近 被发现在四环 PAH 上生长，而其他人只共同代谢这些 化合物。 该项目的目的是研究新陈代谢和生物降解 HMW PAH，特别强调识别不完整的产品 可能在水相中积累的代谢；研究动力学 HMW PAH 降解；评估其他 PAH 对发生率的影响 混合物中存在 HMW PAH 时会发生降解；评估潜力 HMW PAH 代谢诱导剂，可用于维持生长 在其主要生长底物后共代谢 HMW PAH 的细菌 已耗尽；评估传质过程对 HMW PAH 降解的速率和程度；并评估策略 提高传质限制下 HMW PAH 的降解程度 情况。 使用 PAH 降解细菌即可实现这些目标 从各种受污染的土壤中分离出来，其中似乎含有 PAH 代谢的不同途径/其中一些细菌也具有 可能使它们影响传质过程的特性。 将使用以下方法对这些细菌进行代谢物产生的证据筛选： 光谱方法和放射性标记底物的质量平衡。 代谢物分析将采用大规模不断发展的技术 光谱法有助于鉴定极性、非挥发性化合物。 感兴趣的传质过程包括 PAH 从非 水相和土壤有机质的解吸。 定量 将开发模型以确定生物降解可以量化 使用独立测量的速率参数，并作为识别的工具 那些可能影响传质过程的生物体。 策略 提高 HMW PAH 的生物降解性，将作为生长底物 以及使用非离子表面活性剂来提高生物利用度 这些化合物。