Abstract: MM-7，a group of mixed bacteria selected from effective bacterium strains under the laboratory condition was employed to produce immobilized microorganism with YJ-05，a natural organic carrier in adsorption. Then the immobilized microorganism and free bacteria were used to simulate the remediation of oil contaminated soil to investigate the order of importance of 5 factors in different restoring stages with the method of orthogonality，in which the ratio of C，N，P，the amount of bacteria added，the amount of oil，oxidant and surfactant were considered. The results indicated that the order of importance of factors changed in different degradation stages and different kinds of microorganisms. 21-day experiment showed that the rate of petroleum hydrocarbon degradation retains 27.12%，the amount of bacteria was the most important factor，the amount of surfactant followed in the early stage，and the amount of oil also influenced a lot in the middle and last stage.

Key words: oil-contaminated soil, immobilized bacteria, free bacteria, degradation of oil, influencefactors

摘要： 针对石油污染土壤修复，利用实验室已筛选的高效石油降解混合菌MM-7，以天然有机材料YJ-05为载体，吸附法制备固定化微生物。并将游离与固定化微生物应用于室内花盆模拟修复石油污染土壤，对C/N/P、微生物投加量、石油含量、氧化剂和表面活性剂设计五因素四水平正交实验，探讨不同修复时期各影响因素的重要性顺序。实验结果表明，不同微生物在不同降解时期，各影响因素的重要性会发生变化；经过21 d的修复，固定化MM-7对石油烃类的降解率为27.12%，修复过程中，接种量一直是最重要的影响因素，在降解初期表面活性剂影响较大，降解中后期土壤石油含量变为重要影响因子。

关键词: 石油污染土壤, 固定化菌, 游离菌, 石油降解率, 影响因素