陇东黄土高原植物微生物组合联合修复石油污染土壤降解机制研究

Nowadays, the ecological restoration of petroleum hydrocarbon contaminated soil in crude oil exploitation area has become a hot spot in the field of environmental protection, and combined bioremediation with plant and microbes has attracted much attention. However, the crude oil biodegradation rate and effect of ecological restoration are largely restricted by the soil environment factors, and thereby it is a good idea to reduce the TPHs ecological toxicity by using local soil category-appropriate native plant species and local crude oil-degradating microflora. But, little is reported that the interactive influence of the combined bioremediation with native plant species and local crude oil-degradating microflora on petroleum hydrocarbon contaminated soil in the loess plateau of eastern Gansu province and this limits our understanding for the influence of degradation mechanism on petroleum hydrocarbon contaminated soil. Then, how do the combined bioremediation with native plant species and local crude oil-degradating microflora respond to the soil environment factors? What do play a key role in relationship among the combined bioremediation, Plant rhizosphere exudation, total petroleum hydrocarbon component and physical and chemical properties of soil? To answer the above questions, we plan to investigate the relationship among the combined bioremediation, Plant rhizosphere exudation, total petroleum hydrocarbon component and physical and chemical properties of soil and reveal the Degradation mechanism and the optimal degradation conditions of the combined bioremediation between local soil category-appropriate native plant species and local crude oil-degradating microflora to petroleum contaminated soil in the loess plateau of eastern Gansu province. Our research will provide new insights in the selection bioremediation approach and improvement its biodegradation effect.

目前，原油开采区石油烃(TPHs)污染土壤的生态修复已成为环保领域研究热点，其中植物-微生物联合修复备受关注。而植物微生物组合联合修复中土壤微生物和植物发挥活性的条件相对苛刻，易受多种环境因子的影响，极大的制约了该地区TPHs污染生态修复机制的理解，影响了修复效果。为此本项目拟通过筛选适生植物联合土著石油降解菌群开展陇东黄土高原地区石油污染物生态修复，通过监测场地修复中土壤TPHs和植物根际分泌物组分变化和土壤生物学环境因子及非生物学环境因子的改变，分析探讨陇东地区土著同生降解菌群联合适生植物如何响应土壤环境因子，适生联合修复过程中土著降解菌群与植物根际分泌物及TPHs组分和土壤理化性质间有何种联系，进而揭示适生组合联合修复石油污染土壤降解机制，为陇东地区油污土壤的生物修复技术的应用提供科学依据和技术支撑。

通过对陇东黄土高原植物微生物组合联合修复石油污染土壤降解机制研究，阐明了陇东地区土著油污土壤微生物群落结构特征，筛选了4株适生高效原油降解功能菌株并构建了高效原油降解复合菌群，解析了原油污染物对适生植物与土著石油降解菌群联合修复体系的响应机制，揭示了植物微生物联合修复对原油污染物的降解机制，为后续为后期资源开发和技术应用提供了科学依据和理论基础。主要结果如下：.（1）陇东黄土高原地区原油污染土壤微生物群落结构在门分类水平主要包括变形菌门、拟杆菌门和厚壁菌门；在属分类水平主要包括根瘤菌属、纤维菌属、KCM_B_112、原小单孢菌属、Proteiniphilum属、假单胞菌属、假黄色单胞菌属等。原油污染物进入土壤后土壤理化和酶活性均不同程度受到抑制，且随着油污浓度增加该抑制作用也随之增加。.（2）共筛选得到4株高效原油降解功能菌株（分别隶属于赖氨酸芽孢杆菌属、苍白杆菌属、寡养单胞菌属、微小杆菌属）并解析了TPH降解谱，优化了降解条件；通过响应面法构建原油降解复合菌群，与4株原油降解菌等比例混合TPH去除率相比，去除率提升了11.23%，为后续成果应用提供了基础。.（3）菊科植物根区土壤TPH去除率明显高于豆科植物，且陇东黄土高原地区外源施用有机肥可有效提升植物修复效果，其最优添加量为5%。此外，对C20~C28原油污染物的生物降解作用相对较弱是决定菊科植物-微生物复合菌剂处理组修复效果优于紫花苜蓿-微生物复合菌剂修复处理组的关键因素。.（4）植物微生物联合修复时，植物微生物联合修复效果受植物种属差异性的影响，其中菊科植物无论从单独修复和联合修复角度来看，其参与的修复处理组的原油污染物降解率均相对较高，其中降低土壤pH，提升土壤氧化还原酶活性、原油降解功能基因表达量以及微生物群落群落结构是决定其良好修复效果的关键因素。