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Title (Primary) Rhamnolipid biosurfactants decrease the toxicity of chlorinated phenols to Pseudomonas putida DOT-T1E
Author Chrzanowski, Ł.; Wick, L.Y.; Meulenkamp, R.; Kästner, M.; Heipieper, H.J.;
Journal Letters in Applied Microbiology
Year 2009
Department UMB; UBT;
Volume 48
Issue 6
Language englisch;
Keywords bioavailability; chlorinated phenols; phenol; rhamnolipids; surfactants; toxicity
Abstract Aims: To investigate the effect of a mixture of rhamnolipid R1 and R2 biosurfactants produced by a Pseudomonas aeruginosa strain on the toxicity of phenol and chlorophenols to Pseudomonas putida DOT-T1E.Methods and Results: Toxicity was quantified by the effective concentration 50% (EC50), that is the concentration that causes a 50% inhibition of bacterial growth. The presence of 300 mg l-1 rhamnolipids, that is at about twice their critical micelle concentration (CMC), increased the EC50 of phenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,5-trichlorophenol by about 12, 19, 32 and 40%, respectively, and consequently reduced the bioavailability and the freely dissolved concentration of the toxic phenolic compounds. The reduction was related to the phenols' octanol-water partition coefficients (Kow).Conclusions: The reduction in toxicity of the phenols can be explained by a combination of toxin accumulation in biosurfactant micelles and hydrophobic interactions of the phenols with rhamnolipid-based dissolved organic carbon.Significance and Impact of the Study: Results provide evidence that next to the effect of the micelle formation also hydrophobic interactions with rhamnolipid-based dissolved organic carbon affects the bioavailability of the phenols. Quantifying the effect of biosurfactants on the toxicity of hydrophobic compounds such as phenols thus appears to be a useful approach to assess their bioavailable equilibrium concentration.
ID 117
Persistent UFZ Identifier http://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=117
Chrzanowski, Ł., Wick, L.Y., Meulenkamp, R., Kästner, M., Heipieper, H.J. (2009):
Rhamnolipid biosurfactants decrease the toxicity of chlorinated phenols to Pseudomonas putida DOT-T1E
Lett. Appl. Microbiol. 48 (6), 756 - 762