基于电活性微生物的芳香烃类污染物转化机制研究进展

Transformation mechanism of aromatic hydrocarbon pollutants based on electroactive microorganisms

摘要:

芳香烃类化合物(aromatic hydrocarbon compounds)是一类基于苯环结构的有机物，广泛分布在自然环境中，难以自然降解、易被生物积累，且有很大的环境危害性。生物法是有机化合物转化降解的主流工艺，而电活性微生物(electroactive microorganisms,EAM)因其独特的胞外电子传递(extracellular electron transfer,EET)能力和生理代谢模式在芳香烃类化合物污染修复领域具有巨大的应用潜力。电活性微生物可以通过还原脱卤、脱硝与氧化开环过程相结合的方式，最终实现芳香烃类污染物的降解矿化。本文重点综述了电活性微生物降解芳香烃类污染物过程中主要还原/氧化反应机理，归纳了电活性微生物高效还原脱卤、脱硝的关键酶活、代谢途径及转化机理，分析了不同含氧条件下电活性微生物开环方式及降解代谢途径，并通过调控微生物胞外聚合物与添加导电材料等途径来提升电活性微生物的胞外电子传递过程，总结了电极电位、电极材料、电解液性质及温度等环境因子对芳香烃类化合物降解的影响，探讨了芳香烃类污染物的强化生物降解策略的可行性。最后，展望了电活性微生物降解技术相关领域未来潜在的研究方向，以期为加快生物电化学系统的工程化应用提供理论和技术参考。

Abstract:

Aromatic hydrocarbons, a class of organic compounds with one or more benzene rings, are ubiquitous in the natural environment. They are difficult be degraded naturally and thus easy to be bioaccumulated, posing a huge threat to the environment. Biological degradation seems to be the mainstream method for the transformation of organic compounds, and electroactive microorganisms have great potential in the removal of aromatic hydrocarbons because of their unique extracellular electron transport ability and physiological metabolism mode. They can finally achieve the degradation and mineralization of aromatic hydrocarbon pollutants by combining reductive dehalogenation and denitrification and oxidative ring cleavage. In this paper, we focused on the main reduction/oxidation reaction mechanisms in the degradation of aromatic hydrocarbon pollutants by electroactive microorganisms, summarized the key enzyme activities, metabolic pathways, and transformation mechanism of electroactive microorganisms in the reductive dehalogenation and denitrification, analyzed the ring cleavage modes and metabolic pathways of electroactive microorganisms under different oxygen-containing conditions, and improved the extracellular electron transport process of the microorganisms by regulating microbial extracellular polymers and adding conductive materials. Moreover, we discussed the influence of electrode potential, electrode materials, and environmental factors such as electrolyte properties and temperature on the degradation of aromatic hydrocarbon compounds, and the feasibility of enhanced biodegradation strategies for aromatic hydrocarbon pollutants. Finally, in order to provide theoretical and technical reference for accelerating the engineering application of bioelectrochemical systems, we summed up the directions of future potential research in the related fields of electroactive microbial degradation technology.