(669h) Marine Bacteria Adhesion to Oil/Water Interfaces

Bose, A., University of Rhode Island
Tripathi, A., Brown University
Godfrin, M., Quest Consultants Inc.
Alcanivorax Borkumensis is a hydrocarbon-degrading bacterium that dominates hydrocarbon-degrading bacterial communities around many oil spills. A. Borkumensis cells were grown either with dissolved organic carbon (no-spill condition) or with hexadecane layer (oil spill condition) as the sole energy source. Bacterial ability to adhere to the oil/water interface post-growth was monitored using interfacial tension, bacteria cell hydrophobicity measurements and fluorescence microscopy. Our experiments show that A. Borkumensis grown with dissolved organic carbon as the sole energy source remain hydrophilic and do not show significant adhesion to the oil/water interface. The bacteria grown under the hexadecane layer become partially hydrophobic and adhere to oil/water interfaces, where they reduce interfacial tension and form the early stages of a biofilm.  We show that the biosurfactant produced by A. Borkumensis after exposure to hydrocarbons stay bound to bacterial cell membranes. Thus biosurfactant synthesis is vital for the bacteria to able to adhere to oil/water interfaces, which subsequently permits the bacteria to utilize hydrocarbons as an energy source. This study provides key insights into how A. Borkumensis accesses and degrades oil.