满江红和满江红鱼腥藻组成的植物-微生物共生体系去除水中铀的机理

The remediation of the radioactive wastewater from uranium mining and metallurgy is a difficult task since feasible and low cost and effective approach has not been proposed yet. This project is proposed on the basis of previous research results.The sophisticated instruments and superior experimental conditions in the Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy are important premises for this project. The plant-microbe symbiotic system consisting of Azolla imbricata and Anabena azollae is selected as the object of study, due to its potential of removing uranium from aqueous solutions. The research methods include field sampling, laboratory test, analytical test, theoretical analysis. The pattern by which the symbiotic system removes uranium from aqueous solutions, the physiological and biochemical responses of the symbiotic system to be uranium stess and the speciation, valence state, subcellular distribution, metal ligand of uranium in the Azoila imbricata and Anabaena azollae will be investigated to reveal the mechanism of the symbiotic system for removing uranium from aqueous solutions.The project will provide the theoretical basis for establishing a new efficient plant-microbe symbiotic system. The project is an innovative one that crosses over uranium mining and metallurgy, environmental sciences, microbiology and phytology. The project has important significance for enriching and developping the bioremediation theory and method for treatment of the radioactive wastewater from uranium mining and metallurgy and promoting the sustainable development of uranium mining and metallurg industry for our country.

铀矿冶放射性废水的修复是亟待研究解决的重大而紧迫的科技问题。本项目利用申请者所在实验室的先进仪器设备和优越的试验条件，以大量的前期研究为基础，以能高效去除水中铀的满江红和满江红鱼腥藻组成的植物-微生物共生体系为研究对象，采用现场取样、室内实验、分析测试和理论分析等方法，开展满江红和满江红鱼腥藻组成的植物-微生物共生体系高效去除水中铀的途径、对铀胁迫的生理生化响应以及铀在满江红和满江红鱼腥藻的赋存形态、价态、亚细胞分布及金属配位体等方面的研究，揭示满江红和满江红鱼腥藻组成的植物-微生物共生体系高效去除水中铀的机理，为建立新的能高效去除水体中铀的植物-微生物共生体系提供理论依据。这是一项铀矿采冶、环境科学、微生物学、植物学等多学科相互交叉的创新性研究。本项研究对于丰富和发展铀矿冶放射性废水的生物修复理论及方法，促进我国铀矿采冶工业可持续发展都具有重要的意义。

本项目研究了满江红和鱼腥藻组成的植物-微生物共生体系(有藻满江红)高效去除水中铀的行为；满江红和鱼腥藻共生体系去除水中铀的途径；鱼腥藻在满江红-鱼腥藻共生体系去除水中铀时的作用；满江红和鱼腥藻共生体系对铀胁迫的生理生化响应；满江红-鱼腥藻共生体系对不同形态铀的吸附行为；以及铀在有藻满江红、无藻满江红、鱼腥藻的亚细胞分布以及赋存价态、形态。揭示了鱼腥藻提高了有藻满江红对水中铀的富集量、富集系数以及对铀的抗胁迫能力，从而提高了有藻满江红对水中铀的去除效率。红外分析表明，在富集铀后，与无藻满江红相比，有藻满江红体内出现了芳环和醇类或苷类化合物，而这些新的物质是鱼腥藻在富集铀的过程中产生的，其可能促进了有藻满江红对铀的富集。透射电镜和能谱分析表明，铀主要赋存在有藻满江红根部细胞细胞壁壁中，有藻满江红叶部细胞中基本不赋存铀。有藻满江红、无藻满江红和鱼腥藻体内赋存的铀主要是六价铀，其吸收、转运和储存过程中没有发生铀的价态转变；有藻满江红体内赋存的铀中磷酸铀酰占60%，U-C占30.0%；无藻满江红体内赋存的铀中磷酸铀酰占45%，U-C占50%；有藻满江红体内赋存的铀中磷酸铀酰占60%，U-C占33.3%。有藻满江红与鱼腥藻体内赋存的铀的形态基本一致，而无藻满江红体内赋存的铀中磷酸铀酰的比例低于有藻满江红与鱼腥藻，而U-C的比例高于有藻满江红与鱼腥藻。通过无藻满江红和鱼腥藻协同高效去除水中铀的机理，构建出了新的对水中铀具有高效去除作用的合果芋（植物）-黑曲霉（微生物）和合果芋（植物）-pseudomonas reactans（微生物）两个植物-微生物共生净化体系，构建的植物-微生物共生体系能使浓度为0.5-5 mg/L 铀污染水体在40 d内将至GB 23727-2009 规定的0.05 mg/L 排放标准以下。