论文部分内容阅读
多溴联苯醚(PBDEs)是一种曾在全球范围内被广泛使用的溴代阻燃剂,具有半挥发性、生物蓄积性、神经毒性和内分泌干扰效应等,严重威胁生态环境和人体健康安全。本研究选择典型好氧降解菌伯克氏菌属LB400,对环境中普遍检出的中低溴联苯醚开展了降解动力学过程研究,探讨了外加碳源作为共代谢底物对降解性能的影响,模拟计算了降解中关键反应路径热力学状态函数性质变化,以揭示其与表观降解速率常数k之间的相关关系。结果表明:联苯作为共代谢底物时PBDEs的去除效率最高,在降解菌的作用下,0~120 h内中低溴代PBDEs均能够发生降解,降解过程符合一级反应动力学。羟基化反应可能是PBDEs微生物降解过程的速控步骤,相比于间/对位取代,活性氧自由基如·OH更倾向于攻击苯环碳原子的邻/间位置,这为揭示PBDEs好氧微生物降解的分子作用机制,促进土壤中高效好氧降解菌的选育与污染修复应用提供了科学依据。
Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants that have been widely used worldwide. They have the effects of semi-volatility, bioaccumulation, neurotoxicity and endocrine disrupting, which seriously threaten the ecological environment and human health and safety. In this study, a typical aerobic biodegradation strain of Burkholderia LB400 was selected to study the degradation kinetics of low and medium-brominated diphenyl ethers commonly found in the environment. The effects of external carbon sources as co-metabolism substrates on the degradation performance Influence, the thermodynamic state function of the key reaction path in degradation was simulated and the correlation between them was revealed with the apparent degradation rate constant k. The results showed that the removal efficiency of PBDEs was the highest when biphenyl was used as a substrate for co-metabolism. Under the action of degrading bacteria, PBDEs could degrade in 0-120 h, and the degradation process accorded with the first-order reaction kinetics. Hydroxylation may be the rate-controlling step in microbial degradation of PBDEs. Compared with m / p substitution, reactive oxygen species, such as · OH, are more likely to attack the ortho / It provides a scientific basis for the molecular mechanism of microbial degradation and promoting the selection and remediation of highly aerobic degrading bacteria in soil.