酚类物质是许多国家优先控制的污染物，提高总有机碳（TOC）的去除是含酚废水处理工程的关键。前期我们获得一株耐高浓度且快速降解苯酚的施氏假单胞菌（命名为 P.stutzeri N2），研究发现该菌在降解苯酚的初始阶段TOC容易升高，并证实了该菌在好氧条件下同时存在羧化（容易使TOC升高）和羟化（环烃易断裂，TOC不易积累）两种代谢途径。本课题在前期工作基础上，拟从分子生物学和生理生化角度理解该菌降解苯酚的途径，并建立提高TOC快速去除的条件。研究反应条件和快速去除苯酚TOC的相关性；研究苯酚羟化酶、羧化酶活性和表达量与 TOC 升高的相关性；在此基础上，通过构建基因工程菌，使苯酚降解按照有利于提高TOC去除率的反应途径和条件进行。本研究的完成将阐明P.stutzeri N2降解苯酚过程中TOC快速降低的调控机制，为P.stutzeri N2在含酚废水处理中的实际应用奠定基础。

Phenolic compounds have been listed as priority pollutants by many countries. Improvement of removal of their total organic carbon (TOC) is crucial for phenols-containing wastewater treatment. We have isolated a Pseudomonas stutzeri strain (named P. stutzeri N2), which could tolerate the high-concentration phenol, and also could degrade the phenols with a high rate. But we found that TOC easily increased during the initial stage of phenol degradation. Based on the metabolites which had been identified by us, we confirmed that the strain had two coexistence metabolic pathways under aerobic conditions, one is carboxylation (easily cause TOC increase) and the other is hydroxylation (hydrocarbon cyclic easily broken, and TOC not accumulation easily). This proposal project is based on the previous research. We are intersted in understanding the pathways from the molecular biology and from physiology and biochemistry aspects. We will study on the relationship between the reaction conditions and rapid removal of TOC during phenol degradation by the P. stutzeri N2; reveal the correlations between the expression levels of carboxylase(or hydroxylase) and TOC changing trends during the biodegradation; By constructing the corresponding genetic engineering bacteria, phenols metabolism will carry out according the pathway and under the conditions which are benefit for echancing phenol TOC removal. This study will illustrate the regulation mechanism of TOC rapid decrease during phenol degradation by the P.stutzeri N2, and will lay a foundation for the practical application of the P.stutzeri N2 in phenolic wastewater treatment.