Effect of non-ionic surfactants on elimination of polycyclic aromatic hydrocarbons (PAHs) in soil-slurry by Phanerochaete chrysosporium

Abstract

Surfactants can enhance bioremediation of soil contaminated with polycyclic aromatic hydrocarbons (PAHs) by increasing their bioavailability. The objective of this study was to evaluate the effect of non-ionic polyoxyethylene (POE) surfactants on the elimination of nine PAHs in contaminated soil by the white rot fungus Phanerochaete chrysosporium. PAHs in both liquid and solid phases were extracted and then assayed using GC-MS. Fungal biomass concentration and the activity of extracellular ligninolytic enzymes were used to determine the toxicity of POE surfactants. Results indicated that 0.5% (w/v) of surfactant Tween 80 was not toxic to fungal growth and had little impact on extracellular ligninolytic enzyme synthesis. About 80% of low ring PAHs (ie acenaphthene and fluorene) could be efficiently catabolized by P chrysosporium without surfactants, while catabolism of others (ie phenanthrene, fluoranthene, pyrene, chrysene, benzo(a)pyrene, dibenz(a-h)anthracene and benzo(ghi)perylene) was less than 30% over a 8-day culture period. Elimination of four-to-six-ring PAHs in contaminated soil was enhanced in P chrysosporium cultures with 0.4% (w/v) Tween 80 by 15-33% compared with those in cultures without Tween 80, while no obvious effect was observed in the elimination of three-ring PAHs over the culture period. Investigations on PAH concentrations in aqueous phase during the culture period showed that Tween 80 increased PAH aqueous concentrations and the PAH oxidation rate in aqueous was rapid. Enhancement of soil PAH elimination in the presence of Tween 80 was due to the increased PAH bioavailability. © 2001 Society of Chemical Industry.