多菌体-石墨烯强化火凤凰修复原PAHs-Cd复合污染土壤中的调控技术及根际区生态代谢组学研究

In this project, we will study on the control technique and rhizosphere eco metabolomics of phytoremediation on PAHs-Cd actual co-contaminated soils using Fire Phoenix enhanced by multi-bacteria-graphene. And the mechanism of pollutants removal will be investigated through the aspects of rhizosphere soil and plants by the measures of metabolomics, genomics combined with proteomics. Firstly, in the field of rhizosphere soil, the typical intermediate products will be screened out and analyzed systematically. Simultaneously, the structures of microbial community in rhizosphere soil and the characteristics of two important enzymes in the phytoremediation process were explored. By the way, we will clarify the interaction between them and the metabolic responses of pollutants. Secondly, in terms of plant, metabolomics analysis will be used to analyze the metabolic profile of phoenix root samples, and the differential metabolites analysis will be used to explore the metabolic pathways of two pollutants. At the same time, the differences gene of Fire Phoenix on the degradation of PAHs and Cd will be studied by gene chip hybridization, and then, the proteomics response mechanism of Fire Phoenix will be explored through the proteomics. The implementation of this project can not only provides effective treatment solutions for PAHs-Cd co-contaminated sites, but also offer important scientific theoretical basis for revealing the mechanism of joint enhanced restoration for PAHs-Cd contaminated soils by Fire phoenix.

本项目以原PAHs-Cd复合污染土壤为研究对象，通过特定多菌剂添加，结合氧化石墨烯，对污染土壤进行强化调控技术研究。在污染物去除机理方面，结合生态代谢组学、基因组学及蛋白组学多种分析手段，从植物根际土壤和植物体两个方面探究。第一，在根际土壤方面，首先筛选出对PAHs及Cd污染胁迫应激反应的典型中间代谢物，并系统分析其变化规律。同时探究两种污染物去除过程中根际土壤菌群结构与两大重要酶系特征，阐明其与污染物代谢响应间的相互作用关系。第二，在植物体方面，运用代谢组学方法对火凤凰根样本进行代谢轮廓分析，通过差异代谢物的分析探究两种污染物代谢通路；同时，运用基因芯片杂交，研究影响火凤凰降解PAHs和Cd的基因差异；并通过蛋白组学，探讨火凤凰去除PAHs和Cd的应答机制。本项目实施不仅对PAHs-Cd复合污染土壤治理提供强有力实施方案，也能为揭示联合强化火凤凰修复复合污染土壤作用机制提供重要的科学理论

本项目旨在研究氧化石墨烯（GO）介导的火凤凰降解PAH-Cd共污染土壤的效能及微生态系统机制。研究结果表明，在低PAHs（105±18.45 mg-kg-1）和高PAHs（154.55±20.78 mg-kg-1）的共污染土壤中，用0.4 g/kg的GO处理150天后，PAHs去除率分别为78.95%和73.21%，Cd根系富集率被提升到57.99%。GO增强了根部的多环芳烃协同代谢，特别是5环PAHs的去除率增加了55.69%。实验证明GO可作为植物修复有机与重金属复合污染的强化剂。对于根系内微生态系统研究表明：GO主导的火凤凰修复PAH-Cd污染时，降解基因的相对丰度与PAHs去除率呈正相关性，且相对基因丰度受GO影响而增加，如nidA和pdoA2等，因此双加氧酶参与PAHs的直接降解被认定为PAHs的上游降解途径。而PAHs的下游降解途径则主要是根系代谢物与微生物降解菌之间的密切相互作用而参与的间接降解途径。进一步分析表明，GO影响TCA循环占第一主导地位，直接通过上调Crtric acid，Succinic acid，Malic acid，主要为Bacillus、Mycobacterium、Nocardia三种微生物提供碳源和能源，从而促进PAHs的降解。其次是Carbohydrate metabolisma、Amino acid metabolisma分别占第二、第三主导地位。上游降解途径可以作为微生物的唯一碳源和能源，而下游降解途径一般通过与其它基质的共代谢作用进行降解。开展PAHs降解途径的研究可深入了解微生物对PAHs的转化，为生物修复技术的应用提供理论基础。我们的研究揭示了植物和微生物之间相互作用的GO诱导机制。这项工作为控制根瘤微生物群提供了一个具有竞争力的方向，并取得了有益的结果，同时也为使用纳米材料对复合污染的场地提供了一个合适的修复策略。