Interactions between rhamnolipid biosurfactants and toxic chlorinated phenols enhance biodegradation of a model hydrocarbon-rich effluent
[ 1 ] Instytut Technologii i Inżynierii Chemicznej, Wydział Technologii Chemicznej, Politechnika Poznańska | [ P ] employee | [ D ] phd student
2011
scientific article
english
- wastewater
- 4-chlorophenol
- 2
- 4-dichlorophenol
- diesel fuel
- rhamnolipids
- toxicity
EN Surfactant-mediated treatment increases hydrocarbon solubilization and potentially facilitates biodegradation, unless toxic co-contaminants inhibiting microbial activity are present in the hydrocarbon mixture. We assessed the effect of rhamnolipids on the performance of a bacterial consortium degrading diesel fuel employed as a model hydrocarbon-rich effluent, co-contaminated with toxic phenol, 4-chlorophenol (4-CP) or 2,4-dichlorophenol (2,4-DCP). This approach led to the unexpected finding that rhamnolipids reduced toxicity of 4-CP and 2,4-DCP to the hydrocarbon-degrading cells. The facts that rhamnolipids decreased diesel fuel – water partition coefficient (KFW) of 4-CP and 2,4-DCP and modified aggregate size distribution profiles of the dispersed diesel fuel – chlorinated phenols solutions, suggest the existence of specific interactions between rhamnolipids and the co-contaminants. Due to the polar nature of 4-CP and 2,4-DCP, possible explanations involve adsorption of 4-CP and 2,4-DCP on the surface of biosurfactant aggregates. This property of rhamnolipids is of interest to those using biosurfactants for microbial treatment of hydrocarbon-rich wastewaters co-contaminated with toxic compounds.
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