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: 6271205
• 负责人: MICHAEL AITKEN
• 金额: $ 23.18万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6271205
• 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）是土壤中的主要污染物， 地下水在美国各地的一些网站。 他们中的许多 已知或疑似致癌物，但也有许多已知 生物降解的细菌和真菌本土的天然和污染 土壤 生物过程已被用于修复多环芳烃污染 土壤，但去除高分子量（HMW），致癌物质 往往是不完整的。 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那些）比已知的 降解二环和三环化合物。 一些细菌最近 已经发现生长在四环多环芳烃，而其他人只共代谢这些 化合物. 本项目的目的是研究代谢和生物降解 高分子量多环芳烃，特别强调识别产品的不完全 可能在水相中积累的代谢;研究动力学 高分子量多环芳烃降解速率的影响;评估其他多环芳烃对高分子量多环芳烃降解速率的影响。 混合物中存在的HMW PAH降解;以评估潜在的 高分子量多环芳烃代谢的诱导剂，可用于维持生长， 在其主要生长底物后共代谢HMW PAH的细菌 消耗;评估传质过程对 高分子量多环芳烃降解的速度和程度;并评估战略， 提高高分子量多环芳烃降解的程度， situations. 这些目标将通过使用多环芳烃降解细菌来实现， 从各种污染土壤中分离出来， PAH代谢的不同途径/其中一些细菌还具有 这些特性可能会影响传质过程。 这些细菌将被筛选代谢产物生产的证据，使用 光谱方法和放射性标记底物的质量平衡。 代谢物的分析将采用不断发展的技术， 光谱法，以帮助鉴定极性，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 那些可能影响质量传递过程的微生物。 的战略 提高高分子量多环芳烃的生物降解性将英镑作为生长基质 以及使用非离子表面活性剂来增加 这些化合物。