title: Estimation of direct-contact fraction for phenanthrene in surfactant solutions by toxicity measurement.
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 x 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 x 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 x 10(-4)M Brij 35 and 7.6 x 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.
authors: Advanced Environmental Biotechnology Research Center, Department of Chemical Engineering/School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-Dong, Nam-Gu, Pohang, Gyeongbuk, Republic of Korea.
authors: Hyo J
authors: HJ
authors: Lee
authors: Min W
authors: MW
authors: Lee
authors: Dae S
authors: DS
authors: Lee
authors: Seung H
authors: SH
authors: Woo
authors: Jong M
authors: JM
authors: Park
mesh_terms: D050296:Microbial Viability / Q000187:drug effects; D010616:Phenanthrenes / Q000633:toxicity*; D016958:Pseudomonas putida / Q000187:drug effects*; D012995:Solubility / Q000187:drug effects; D012996:Solutions; D013501:Surface-Active Agents / Q000633:toxicity*; D018675:Toxicity Tests
chemical_list: D010616:Phenanthrenes; D012996:Solutions; D013501:Surface-Active Agents; C031181:phenanthrene