Abstract
The toxicity of solutions containing nonionic surfactants Tween 80, Brij 35 and/or phenanthrene to Pseudomonas putida ATCC 17484 was investigated. The fraction of direct contact between micellar-phase phenanthrene and bacterial cell surface was estimated by using the toxicity data and a mathematical model. The mathematical model was used to calculate phenanthrene concentration in the micellar phase and aqueous pseudophase separately. The first-order death rate constant increased from 0.088 ± 0.016 to 0.25 ± 0.067 h-1 when the phenanthrene concentration was increased from 0 to 5.17 × 10-6 M (equals water solubility). The intrinsic toxicity of surfactant was higher in Brij 35 than in Tween 80. When phenanthrene concentration was increased to 9.7 × 10-5 M in surfactant solutions, the death rate constant increased to 1.8 ± 0.024 and 0.41 ± 0.088 h-1 for 8.4 × 10-4 M Brij 35 and 7.6 × 10-4 M Tween 80. The direct-contact fraction was 0.083 and 0.044 for Brij 35 and Tween 80, respectively, under these conditions using exponential model. The toxicity increased with increasing phenanthrene concentration at a fixed surfactant concentration. The toxicity decreased with increasing the surfactant concentration at a fixed phenanthrene concentration due to decreased contact of bacteria with phenanthrene present in the interior of surfactant micelles.
Original language | English |
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Pages (from-to) | 448-457 |
Number of pages | 10 |
Journal | Journal of Biotechnology |
Volume | 131 |
Issue number | 4 |
DOIs | |
State | Published - 30 Sep 2007 |
Keywords
- Bioavailability
- Direct contact
- PAH
- Surfactant
- Toxicity