土著产黄青霉浸出修复重金属重污染土壤机理研究

A large amount of slags rich in kinds of heavy metal have been produced during Pb/Zn smelting process. The smelting slags were directly piled so that the soil was polluted severely by heavy metal at the Pb/Zn smelting slag site. Remediation on the soil at Pb/Zn smelting slag site is a focus in the world, especially in China. Developing of an environment friendly,simple to operate,quickly to achieve and cost effective remediation technology on heavy metal compound pollution in soil is necessary. A Penicillium chysogenum, which has heavy metal resistance and is able to produce organic acid has been isolated from the polluted soil on Pb/Zn smelting slag site in the preliminary study. The leaching amount of heavy metal using Penicillium chrysogenum is 323.2 mg/L from the polluted soil , in which heavy metal content is as high as 12.62g/kg,so the bioleaching remediation effect was good, but the bioleaching mechanism is unclear.The followings will be researched using 13C metabolic flux analysis method (13C-MFA) and canonical correlation analysis (CCoA) method combined with analytical tools such as HPLC, MS and NMR: 1) the mechanism and approach of producing organic acids by Penicillium chrysogenum under multidimensional environment; 2) the leaching dynamics mechanism of Penicillium chrysogenum; 3) the characterization of leaching technology for Penicillium chrysogenum. Then some results would be obtained : 1) the leaching mechanism would be revealed at the molecular level; 2) the leaching efficiency and amount would be increased; 3)the technological characteristic on bioleaching heavy metals from heavily polluted soil at the Pb/Zn smelting slag site would be clarified. The project aims to provide basic theory on bioleaching remediation of heavy metal heavily compound pollution in soil using microbiology and a bioleaching technical prototype for the soil at Pb/Zn smelting slag site using indigenous Penicillium chrysogenum would be achieved.

铅锌冶炼废渣堆场土壤遭受重金属复合污染，急需发展清洁高效、成本低廉的冶炼废渣堆场土壤治理技术。项目组已从某大型冶炼厂冶炼废渣堆场重污染土壤中筛选到一株具重金属抗性和产酸能力的产黄青霉，该菌株对重金属含量高达12.62 g/kg重污染土壤中重金属的浸出量为323.2 mg/L，对严重重金属复合污染土壤具有良好的修复效果，但对其作用机理不明。本项目拟采用13C元素示踪代谢通量分析法和典范相关分析法，结合高效液相色谱、同步辐射X射线吸收光谱技术和核磁共振等分析手段，研究：1) 产黄青霉的产酸机制；2) 浸出修复动力学机制；3) 浸出修复重污染土壤工艺特征，揭示产黄青霉浸出修复重金属的作用机理。本项目研究旨在阐明重金属重污染土壤微生物修复的基础理论，形成土著产黄青霉浸出修复严重重金属复合污染土壤技术原型。

为治理冶炼场地重金属严重污染土壤，拟发展一项重金属污染土壤浸出修复技术原型。本项目研究了：<1> 冶炼场地及周边环境土壤污染状况及土壤物理化学特征，<2> 浸出修复过程中产黄青霉的代谢组学特征，<3> 重金属胁迫下产黄青霉的生理特征及反应机制，<4> 产黄青霉浸出修复重金属污染土壤的工艺特征。本研究得出如下结论：<1> 冶炼场地及周边区域土壤遭受复合重金属（Pb, Zn, Cd 和Cu）的严重污染，横向上随距污染源距离的增加，重金属含量逐渐减少，纵向上随土层深度的增加重金属含量呈减少趋势; <2> 浸出修复过程中，产黄青霉葡萄糖的主要分解途径有糖酵解和三羧酸循环，主要合成途径是磷酸戊糖途径，葡萄糖进入分解途径的量大于合成途径，许多小分子有机酸如柠檬酸、琥珀酸、富马酸、苹果酸、丙酮酸等产生于三羧酸循环，这些小分子有机酸是与土壤中重金属酸解、熬合的主要代谢产物; <3> 在重金属胁迫下部分代谢酶被激活，部分代谢酶活性被抑制，导致代谢产物出现上调或下调的现象。在锌胁迫下，总蛋白含量、CAT酶活和T-SOD酶活均呈现先增加后减少的趋势，铅胁迫下产黄青霉的总蛋白含量随铅浓度的增加呈下降趋势，CAT酶活先增加后下降，T-SOD酶活随铅浓度升高而不断增加；<4> 产黄青霉的浸出修复工艺特征如下：Pb和Zn的最适浸出温度为30℃，Cd和Cu的为20℃；当培养基pH值为7.0时，Pb、Zn、Cd和Cu的浸出率之和最高，Pb和Zn的浸出率之和均在浸出7天时最高。极差分析表明培养基pH值和浸出时间是主要影响因素，方差分析表明培养基pH值和浸出时间对Zn的浸出率影响显著，对Pb、Cd和Cu浸出率的影响均不明显。30℃，pH7.0，浸出7 d时各重金属的浸出率均最高。使用本研究经费已发表论文18篇，拟发表2篇，申请发明专利1项。本研究所得结果将应用于冶炼场地重金属污染土壤的治理，在此技术原型的基础上发展为1项成熟技术，建立1个工程示范。