PBDEs好氧微生物降解动力学过程及热力学机制研究

发布时间：2018-05-01 16:17

本文选题：多溴联苯醚 + 共代谢　；参考：《土壤》2017年01期

【摘要】：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。
[Abstract]:Polybrominated diphenyl ether (PBDEs) is a kind of brominated flame retardants that have been widely used in the world. It has the characteristics of semi-volatile, bioaccumulation, neurotoxicity and endocrine disruptions, which seriously threaten the ecological environment and human health and safety. In this study, a typical aerobic degrading bacterium, LB400, was selected to study the degradation kinetics of low and middle brominated diphenyl ethers, which were commonly detected in the environment, and the effect of external carbon source as a co-metabolic substrate on the degradation performance was discussed. The properties of the thermodynamic state function of the critical reaction path in degradation were simulated and calculated to reveal the correlation between the properties of the state function and the apparent degradation rate constant k. The results showed that the removal efficiency of PBDEs was the highest when biphenyls were used as co-metabolite substrates, and the degradation of PBDEs could occur within 120 h under the action of degrading bacteria, and the degradation process was in accordance with the first-order reaction kinetics. Hydroxylation may be a rapid step in the degradation of PBDEs, and reactive oxygen radicals such as OH are more likely to attack the adjacent / interspace positions of benzene ring carbon atoms than their m / p substitutions. This provides a scientific basis for revealing the molecular mechanism of aerobic microbial degradation of PBDEs and promoting the breeding of high efficiency aerobic degrading bacteria in soil and the application of pollution remediation.
【作者单位】：中国科学院土壤环境与污染修复重点实验室(南京土壤研究所);中国科学院大学;
【基金】：国家自然科学基金项目(21377138);国家自然科学基金项目(41271327和41271464) 国家重点基础研究发展计划(973计划)项目(2014CB441105) 中科院“一三五”计划和领域前沿项目(ISSASIP1618)资助
【分类号】：X592;X172

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