Rhizoremediation of diesel-contaminated soil using the plant growth-promoting rhizobacterium Gordonia sp. S2RP-17

Abstract

A plant growth-promoting rhizobacterium (PGPR) was isolated and identified as Gordonia sp. S2RP-17, which showed ACC deaminase and siderophore synthesizing activities. Its maximum specific growth rate was 0.54 ± 0.12 d -1 at 5,000 mg L -1 of total petroleum hydrocarbon (TPH), and its maximum diesel degradation rate was 2,434.0 ± 124.4 mg L -1 d -1 at 20,000 mg L -1 of TPH. The growth of Zea mays was significantly promoted by the inoculation of Gordonia sp. S2RP-17 in the diesel-contaminated soil. Measured TPH removal efficiencies by various means were 13% by natural attenuation, 84.5% by planting Zea mays, and 95.8% by the combination of Zea mays and Gordonia sp. S2RP-17. The S2RP-17 cell counts were maintained at 1 × 10 6 CFU g-soil -1 during the remediation period, although they slightly decreased from their initial numbers (2.94 × 10 7 CFU g-soil -1). These results indicate that rhizoremediation using both Zea mays and Gordonia sp. S2RP-17 is a promising strategy for enhancing remediation efficiency of diesel-contaminated soils. © 2010 Springer Science+Business Media B.V.