Potential application of a biosurfactant in phytoremediation technology for treatment of gasoline-contaminated soil

Biosurfactants are amphiphilic compounds excreted extracellularly that contain hydrophobic and hydrophilic moieties, allowing them to accumulate between the fluid phases on an organism and thus reduce the surface and interfacial tension. The objectives of this study were to evaluate the potential application of a biosurfactant to the phytoremediation of gasoline-contaminated soil and compare it to other additives such as hydrocarbon degrading bacteria, sodium dodecyl sulphate (SDS) and bacterial culture supernatant. The results showed that the biosurfactant removed a significant amount (up to 93.5%) of the total petroleum hydrocarbons (TPH) compared with the other additives that removed only 85.4% (bacteria), 70.3% (culture supernatant) and 86.3% (SDS). Kinetic analysis showed that the phytoremediation of gasoline-contaminated soils by the biosurfactant fitted pseudo-second-order kinetics with a coefficient of determination (R-2) of 0.9318 and a second-order rate constant (k(2)) of 0.0032 (g TPH/kg plant d). Thus, biosurfactants have strong potential as supporting biocatalysts to increase the performance of phytoremediation technology for soil treatment. (C) 2015 Elsevier B.V. All rights reserved.