P127: Biodegradation of oil and dispersant by indigenous bacteria isolated in the aftermath of the Deepwater Horizon Spill

The Deepwater Horizon oil spill (2010) resulted in the release of millions of gallons of crude oil and dispersant into the Gulf of Mexico. Several unique hydrocarbon-degrading bacteria were isolated from the Gulf water, from hydrocarbon amended biosep-bead bug traps as well as from sand cores on Elmer’s beach in its aftermath.16S rDNA analysis of the isolates obtained from these sites revealed diverse phylogeny with representatives from Colwellia spp, Pseudoalteromonas spp, Oceanobacillus spp, Vibrio spp, Alcanivorax spp, Pseudomonas spp, Reugeria spp, Shewanella spp and Marinobacter spp among others. Biodegradations of oil of these different isolates were studied at their ambient temperature, and it was observed that most of the isolates were able to rapidly degrade the alkanes component of MC252 oil readily to Carbon dioxide. As COREXIT 9500 was used as the dispersant in large quantities to disperse oil slicks, we also studied it’s biodegradation by some of these indigenous microbial isolates. While enhanced oil degradation rates were observed with isolates in the presence of dispersant, only the propylene glycol and dioctylsulfocussinate components of COREXIT 9500 itself was found to be degraded by the isolates tested.