微生物修复石油污染土壤的分子生态学机制与过程强化途径

The development of remediation techniques for petroleum-contaminated soil is of essential importance to ensure farmland supply and hence the food security of China, a heavy populated country. The soil remediation practice is also related to the sustainable development of petroleum industry. The bioremediation refers to the utilization of microorganisms to convert or degrade hazardous petroleum components. The profiling the microbial community directly illustrates both the distortion of soil by petroleum contaminates and the restoration of the soil being remediated using different treatments and thus gives an ecological insight into the remediation practice and evaluation. While the screening of microorganisms with high degradation capability is the key to the success of bioremediation, the availability of the petroleum hydrocarbons and the enhancment of the uptake and metabolism of pollutants underpins the process efficiency. Using both molecular biology and chemical reaction engineering principles and methodologies, the present study is aimed at 1) monitoring the evolution of microbial community in terms of taxonomic and functional genes, particularly those essential to the nutrient cycling, during the bioremediation process; 2) exploring new methods with molecular ecology insight for screening and constructing of microbial community with a synergistic effect in both the proliferation of working strains and the degradation of oil contaminants, 3) developing new ways to improve the availability of the petroleum hydrocarbon contaminants and integrate both biostimulation and bioaugmentation mechanism and hence give a greatly improved remediation efficiency. The ultimate goal of the proposed study is to provide new methodologies and engineering tools for the development and implementation of bioremediation techniques for petroleum-contaminated arable lands.

石油污染耕地修复技术的研究对于我国耕地与粮食安全和石油企业的可持续发展具有重要的意义。耕地生物修复是利用微生物菌群来代谢和降解土壤中的石油烃污染物，解析生物修复过程中微生物群落变化规律是土壤生物修复的科学基础，筛选具有高效降解能力微生物制剂是提高生物修复效率的关键，提高石油烃的生物可利用度以及促进微生物对污染物的摄取和代谢则是修复过程强化的有效途径。本项目拟将微生物分子生态学技术与化学反应工程的理论和方法相结合，开展如下研究工作：1）石油污染耕地及其修复过程中微生物群落组成、种类和功能的演变行为；2）基于环流驯化和分子生态学技术构建具有协同作用的石油降解微生物菌群的新方法；3）通过提高石油烃污染物生物可利用度以及将生物刺激修复与生物强化修复机制相结合来强化石油污染耕地修复过程的新机制和新过程。通过上述工作为石油污染耕地生物修复工艺的创新和工程应用提供理论指导和关键技术支持。

本项目旨在将微生物分子生态学技术和化学分析相结合动态和多尺度解析生物修复过程中微生物群落变化及其与土壤中石油烃污染物降解动力学之间的内在联系，为生物修复过程过程强化提供理论指导。本项目主要研究成果如下：1)从污染土壤的微生物基因文库、功能基因、土壤表观酶活、污染物组成和含量的变化等方面考察了典型油品如原油、柴油和代表性组分如16烷烃、多环芳烃等对于土壤微生态和土壤功能的影响；观察到土壤自身对于上述油品和组分具有显著不同的降解能力；2)将电喷雾-傅立叶变换-离子回旋共振质谱，气相色谱、液相色谱等化学分析技术化、酶学分析与微生态学分析技术相结合，实时跟踪生物刺激修复过程过程中污染物的降解速率和降解产物与土壤酶活和微生态的变化，揭示了不同修复策略对于污染物去除及微生态恢复的影响规律；3）发展出了环流驯化装置用于土壤污染物降解微生物的筛选并实施了柴油管道泄漏污染场地修复，证实了基于微生态分析强化土壤生物修复过程的可行性。4）对某柴油污染耕地现场进行了场地修复，土壤后各理化性质的指标恢复至正常水平，各项酶活、功能基因指标均达到甚至超过正常值，微生物种群分布恢复正常。场地实验证实了本项目所发展的土壤环流驯化技术筛选降解微生物以及基于微生态学分析来强化生物修复过程的可行性。.上述成果为降解微生物的筛选提供了高效工具；为土壤生物修复策略的选择和过程强化提供了参考；为土壤修复效果评估提供了更为全面可靠的依据。将上述技术和方法应用于土壤中镉的钝化以及农药残留物的降解也取得成功。上述成果证明本研究所发展的综合运用土壤微生态学、酶学和化学反应动力学等可以多维多层次地展现土壤生物修复过程中各个因素的相互关联，为修复过程优化提供指导，在土壤生物修复过程中具有广泛的应用前景。