Bioremediation of oil-contaminated soil using an oil-degrading rhizobacterium Rhodococcus sp. 412 and Zea mays

The advanced bioremediation of diesel-contaminated soil through the exploration of bacterial interaction with plants was studied. A diesel-degrading rhizobacterium, Rhodococcus sp. 412, and a plant species, Zea mays, having tolerant against diesel was selected. Zea mays was seeded in uncontaminated soil or diesel-contaminated soil with or without Rhodococcus sp. 412. After cultivating for 30 days, the growth of Zea mays in the contaminated soil inoculated with Rhodococcus sp. 412 was better than that in the contaminated soil without the bacterium. The residual diesel concentrations were lowered by seeding Zea mays or inoculating Rhodococcus sp. 412. These results indicate that the simultaneous use of Zea mays and Rhodococcus sp. 412 can give beneficial effect to the remediation of oil-contaminated soil. Bacterial community was characterized using a 16S rDNA PCR and denaturing gradient gel electrophoresis (DGGE) fingerprinting method. The similarities of DGGE fingerprints were 20.8-39.9% between the uncontaminated soil and diesel contaminated soil. The similarities of DGGE fingerprints were 21.9%∼53.6% between the uncontaminated soil samples, and 31.6%∼50.0% between the diesel-contaminated soil samples. This results indicated that the structure of bacterial community was significantly influence by diesel contamination.