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Effect of a commercial alcohol ethoxylate surfactant (C11–15E7) on biodegradation of phenanthrene in a saline water medium by Neptunomonas naphthovorans
Biodegradation of poorly soluble polycyclic aromatic hydrocarbons (PAHs) has been a challenge in bioremediation. In recent years, surfactant-enhanced bioremediation of PAH contaminants has attracted great attention in research. In this study, biodegradation of phenanthrene as a model PAHs solubilized in saline micellar solutions of a biodegradable commercial alcohol ethoxylate nonionic surfactant was investigated. The critical micelle concentration (CMC) of the surfactant and its solubilization capacity for phenanthrene were examined in an artificial saline water medium, and a type of marine bacteria, Neptunomonas naphthovorans, was studied for the biodegradation of phenanthrene solubilized in the surfactant micellar solutions of the saline medium. It is found that the solubility of phenanthrene in the surfactant micellar solutions increased linearly with the surfactant concentrations, but, at a fixed phenanthrene concentration, the biodegradability of phenanthrene in the micellar solutions decreased with the increase of the surfactant concentrations. This was attributed to the reduced bioavailability of phenanthrene, due to its increased solubilization extent in the micellar phase and possibly lowered mass transfer rate from the micellar phase into the aqueous phase or into the bacterial cells. In addition, an inhibitory effect of the surfactant on the bacterial growth at high surfactant concentrations may also play a role. It is concluded that the surfactant largely enhanced the solubilization of phenanthrene in the saline water medium, but excess existence of the surfactant in the medium should be minimized or avoided for the biodegradation of phenanthrene by Neptunomonas naphthovorans.
History
Journal
BiodegradationVolume
16Issue
1Pagination
57 - 65Publisher
Springer NetherlandsLocation
Dordrecht , The NetherlandsPublisher DOI
ISSN
0923-9820eISSN
1572-9729Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2005, SpringerUsage metrics
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Keywords
Science & TechnologyLife Sciences & BiomedicineBiotechnology & Applied Microbiologybiodegradationmarine bacteriamicellar solubilizationnonionic surfactantphenanthrenesaline water mediumPOLYCYCLIC AROMATIC-HYDROCARBONSNONIONIC SURFACTANTSSOLUBILIZATIONSOILBIOAVAILABILITYMINERALIZATIONDISSOLUTIONBACTERIUMMicrobiology
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