Inoculation effect of Pseudomonas sp. TF716 on NO emissions during rhizoremediation of diesel-contaminated soil.

The demand for rhizoremediation technology that can minimize greenhouse gas emissions while effectively removing pollutants in order to mitigate climate change has increased. The inoculation effect of NO-reducing Pseudomonas sp. TF716 on NO emissions and on remediation performance during the rhizoremediation of diesel-contaminated soil planted with tall fescue (Festuca arundinacea) or maize (Zea mays) was investigated. Pseudomonas sp. TF716 was isolated from the rhizosphere soil of tall fescue. The maximum NO reduction rate of TF716 was 18.9 mmol NO g dry cells h, which is superior to the rates for previously reported Pseudomonas spp. When Pseudomonas sp. TF716 was added to diesel-contaminated soil planted with tall fescue, the soil NO-reduction potential was 2.88 times higher than that of soil with no inoculation during the initial period (0-19 d), and 1.08-1.13 times higher thereafter. However, there was no enhancement in the NO-reduction potential for the soil planted with maize following inoculation with strain TF716. In addition, TF716 inoculation did not significantly affect diesel degradation during rhizoremediation, suggesting that the activity of those microorganisms involved in diesel degradation was unaffected by TF716 treatment. Analysis of the dynamics of the bacterial genera associated with NO reduction showed that Pseudomonas had the highest relative abundance during the rhizoremediation of diesel-contaminated soil planted with tall fescue and treated with strain TF716. Overall, these results suggest that NO emissions during the rhizoremediation of diesel-contaminated soil using tall fescue can be reduced with the addition of Pseudomonas sp. TF716.