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This article in JEQ

  1. Vol. 40 No. 2, p. 477-483
    Received: June 23, 2010

    * Corresponding author(s): huangg@uregina.ca


Solubilization of Mixed Polycyclic Aromatic Hydrocarbons through a Rhamnolipid Biosurfactant

  1. Hui Yu,
  2. Guohe Huang *,
  3. Jia Wei and
  4. Chunjiang An
  1. Environmental Systems Engineering Program, Faculty of Engineering and Applied Science, Univ. of Regina, Regina, SK, S4S 0A2, Canada. Assigned to Associate Editor Dongqiang Zhu


The solubilization of phenanthrene (PHE) and pyrene (PYR) by rhamnolipid biosurfactant was systematically investigated. The solubilities of both polycyclic aromatic hydrocarbons (PAHs) were increased linearly with the biosurfactant concentration at above critical micelle concentration. A competitive effect was observed between PHE and PYR. The solubility of PHE in a mixed system was lower than that in a single PAH system, whereas the solubility of PYR in a mixed system was enhanced. This is because the hydrophobicity of PYR is higher than that of PHE, so PYR is favored in the competitive solubilization. The combined effect of biosurfactant and dissolved organic matter (DOM) on PAH solubilization was also examined. Two kinds of DOM (derived from soil and from compost) were used. There was an obvious enhancement of solubility for PHE and PYR in systems with concurrence of DOM and biosurfactant compared with systems with only DOM or biosurfactant; however, the enhancement in the mixed system was less than their additive. This could be explained as the formation of a DOM–biosurfactant complex. In addition, the solubility enhancement of PAHs in a compost–DOM system was higher than that in a soil–DOM system. This could be explained as functional group differences of two DOM types.

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