S60: Degradation of oil and dispersant by microbes isolated from the Gulf of Mexico in the aftermath of the MC252 oil spill

The deepwater horizon spill resulted in the release of over 3 million barrels of crude oil into the Gulf of Mexico. In an effort to mitigate large oil slicks, dispersant COREXIT 9500 was injected directly at the well-head at water depth of 1,500m. Oil plume-depth water, contaminated beach sediments, and bug trap samples set up close to the broken well head were collected in the aftermath of the oil spill by our research team. Several incubations were set up at 5°C and at room temperature to identify and isolate the dominant oil and dispersant degrading bacteria. The goal of this study is to characterize these indigenous microbes isolated from the different contaminated sites, and investigate the degradation of oil and dispersant by these microbial species.

Preliminary 16S rDNA analysis of the isolates obtained with oil and/or COREXIT from these sites revealed mostly bacteria similar to Colwellia spp, Pseudoalteromonas spp, Oceanobacillus spp, Vibrio spp, Alcanivorax spp, Pseudomonas spp and Marinobacter spp. Our results indicate that indigenous psychrophilic consortia of microorganisms thriving at 5°C from the oil-plume depth water were better adapted to biodegrade oil and COREXIT. Further, enhanced oil degradation rates were observed with individual isolates in the presence of dispersant.