title: Adhesion to the hydrocarbon phase increases phenanthrene degradation by Pseudomonas fluorescens LP6a.
abstract: Microbial adhesion is an important factor that can influence biodegradation of poorly water soluble hydrocarbons such as phenanthrene. This study examined how adhesion to an oil-water interface, as mediated by 1-dodecanol, enhanced phenanthrene biodegradation by Pseudomonas fluorescens LP6a. Phenanthrene was dissolved in heptamethylnonane and added to the aerobic aqueous growth medium to form a two phase mixture. 1-Dodecanol was non-toxic and furthermore could be biodegraded slowly by this strain. The alcohol promoted adhesion of the bacterial cells to the oil-water interface without significantly changing the interfacial or surface tension. Introducing 1-dodecanol at concentrations from 217 to 4,100 mg l(-1) increased phenanthrene biodegradation by about 30% after 120 h incubation. After 100 h incubation, cultures initially containing 120 or 160 mg l(-1) 1-dodecanol had mineralized >10% of the phenanthrene whereas those incubated without 1-dodecanol had mineralized only 4.5%. The production and accumulation of putative phenanthrene metabolites in the aqueous phase of cultures likewise increased in response to the addition of 1-dodecanol. The results suggest that enhanced adhesion of bacterial cells to the oil-water interface was the main factor responsible for enhanced biodegradation of phenanthrene to presumed polar metabolites and to CO(2).
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada.
authors.forename: Hassan
authors.initials: H
authors.lastname: Abbasnezhad
authors.forename: Julia M
authors.initials: JM
authors.lastname: Foght
authors.forename: Murray R
authors.initials: MR
authors.lastname: Gray
mesh_terms: D001422:Bacterial Adhesion; D001673:Biodegradation, Environmental; D010616:Phenanthrenes / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000502:physiology*
chemical_list: D010616:Phenanthrenes; C031181:phenanthrene