固氮微生物修复石油污染土壤研究进展

Research Progress of Remediation of Petroleum-Contaminated Soil by Nitrogen�Fixing Microorganisms

微生物修复技术因低成本和环境友好的优势已成为当前石油污染土壤修复技术领域的研究热点.然而,石油污染土壤中氮元素限制将会直接影响微生物的修复效果.固氮微生物可以将大气中的氮气(N2)转化成生物可利用性氮素,有利于提升环境氮素水平,对生物修复石油污染场地具有重要作用.本文汇总了石油污染土壤固氮微生物主要类群、固氮微生物修复石油污染土壤的现状以及影响固氮微生物活性的主要因素,以期为石油污染土壤的高效生物修复提供参考.文献资料表明,不同地理区域的固氮微生物种类存在差异,而同一地理区域固氮微生物的群落组成上也存在差异;通过改变碳源可以从混合菌群中分离出兼具固氮作用和石油污染物降解功能的固氮菌株,利用这些土著固氮菌提高了石油污染物的降解率,且复配的菌群在提升石油烃降解效率的同时也往往具有协同作用;温度、氧气和酸碱度是影响固氮微生物功能活性的关键因素.在未来,需要利用先进的技术手段加强固氮微生物资源深度挖掘,为石油污染场地的生态修复提供更多的菌株资源;深入开展固氮微生物及固氮微生物与植物之间的互作机制研究,系统性分析多因素交互作用对固氮微生物的影响,是实现石油污染土壤微生物高效修复的重要基础.

Bioremediation has become a hotspot in the study of the remediation of petroleum-contaminated soil because it is both economic and environmentally friendly.However,nitrogen limitation in petroleum-contaminated soil can directly affect the microbial remediation.Nitrogen-fixing microorganisms convert atmospheric nitrogen into bioavailable nitrogen,which can significantly contribute to the microbial degradation of petroleum.In this paper,we summarized the main groups of nitrogen-fixing microorganisms in petroleum�contaminated soils and the research progress of the remediation of petroleum-contamination soils by nitrogen-fixing microorganisms,and discussed the key factors affecting the activity of nitrogen-fixing microorganisms.We hope this study can provide useful references for the microbial remediation of petroleum-contaminated soils.We found that the groups of nitrogen-fixing microorganisms were distinguishable geographically,but also in the same geographic region due to the variety of microenvironments.Strains with functions of both nitrogen fixation and petroleum-pollutant degradation could be isolated from a mixed flora by changing carbon source.Indigenous nitrogen-fixing bacteria can improve the degradation rate of petroleum pollutants,while compounded strains normally have synergistic effects in enhancing the degradation rate of petroleum hydrocarbons.We also found that environmental factors,such as temperature,oxygen concentration and pH were important in determining the functional activities of nitrogen-fixing microorganisms.Therefore,we recommend more advanced technologies to further use microbial resources and provide more nitrogen-fixing strains for further ecological restoration of petroleum-contaminated soils.In addition,more work needs to be done on the interaction mechanisms among nitrogen�fixing microorganisms and plants,and the systematic analysis of multi-factor interactions of nitrogen-fixing microorganisms.We believe such studies will provide valuable information for the improving the microbial remediation of petroleum-contaminated soils.