MICROBIAL DEGRADATION OF PAH MIXTURES & THEIR INTERMEDIATES

描述(取自应用程序) 许多环境中含有多环芳烃(PAHs)和N-杂环 芳烃(NHAS)是复杂的混合物。具体地说，3000以前 含有PAHs和NHAS的煤气化厂场地构成主要 美国的健康危害。总体目标是加强 去除多环芳烃混合物的生物降解和矿化 含金属和多环芳烃污染土壤中的多环芳烃及其代谢产物 这项建议针对的是顽固的、致癌的4和5环多环芳烃以及 这些土壤中的NHAS和混合物。重点是描述生物化学的特征 和细菌中多环芳烃降解途径的遗传基础，并决定 多环芳烃和金属的复杂混合物对这些降解途径的影响。 因此，具体目标是：1)确定生物降解模式 多环芳烃混合物相对于单个多环芳烃的影响以及金属对 细菌的生物降解性；2)测定4、5环多环芳烃的降解能力 降解器(和3-5环NHA降解器)执行中的限制步骤 土壤微生物的代谢；3)鉴定和表征遗传 高分子量多环芳烃(和NHA)降解基础。这项研究将 包括确定新陈代谢和矿化率，新陈代谢 中间体、反应顺序和反应产物的积累 高效液相色谱/质谱仪/荧光联用仪。藻类最初代谢混合物的能力， 和低分子量降解物和土壤微生物来降解 部分代谢的多环芳烃混合物将用高效液相色谱/质谱仪/荧光法进行测定。 将确定高分子量降解物的多环芳烃降解基因 以及与其他对象的功能和序列相关性 已知的基因将被确定。最后，多环芳烃的发生和分布 土壤种群中的退化基因将用聚合酶链式反应来确定 基于序列信息。通过对微生物的了解 碳氢化合物降解过程，将制定战略，以加强 污染土壤中多环芳烃、氨氮及其中间体的去除

DESCRIPTION (Taken from application) Many environments contain polycyclic aromatic hydrocarbons (PAHs) and N-heterocyclic aromatics (NHAs) as complex mixtures. Specifically, 3000 former sites of coal gasification plants containing PAHs and NHAs constitute major health hazards in the U.S. The overall objective is to enhance the biodegradation and mineralization of mixtures of PAHs for the elimination of PAHs and their metabolites from polluted soils containing metals and PAHs. This proposal targets the recalcitrant, carcinogenic 4 and 5 ring PAHs and NHAs and mixtures in these soils. The focus is to characterize the biochemical and genetic basis of PAH degradation pathways in bacteria and determine the effects of complex mixtures of PAHs and metals on these degradation pathways. Therefore, the specific aims are to: 1) determine the biodegradation pattern of PAH mixtures relative to individual PAHs and the impact of metals on bacterial biodegradation; 2) determine the ability of 4 and 5 ring PAH degraders(and 3-5 ring NHA degraders) to perform the limiting step in metabolism for soil microorganisms; 3) identify and characterize the genetic basis for high molecular weight PAH (and NHA) degradation. This research will involve determining the metabolism and mineralization rates, metabolic intermediates, reaction sequences and accumulation of reaction products by HPLC/MS/fluorescence. The ability of algae to initially metabolize mixtures, and low molecular weight degraders and soil microorganisms to degrade partially metabolized PAH mixtures will be determined by HPLC/MS/fluorescence. PAH degradative genes for high molecular weight degraders will be identified and characterized and the functionality and sequence relatedness to other known genes will be determined. Lastly, the occurrence and distribution of PAH degradative genes in soil populations will be determined using PCR primers based on sequence information. With an understanding of the microbial hydrocarbon degradation process, strategies will be developed to enhance the removal of PAHs, NHAs and their intermediates from contaminated soils.