Using Comparative Metagenomics to Analyze Microbial Degradation of Polar Crude Oil Components

Little is known about the ability of microorganisms to degrade the polar components of crude oil, which are of significant interest because they are more water-soluble and potentially more toxic to marine biota than the non-polar components. Our project seeks to address this gap in knowledge by examining the microbial degradation of the polar components of crude oil in seawater mesocosms using microbial metagenomics (both 16S rRNA amplicon sequencing and shot gun metgenomics). Mesocosms were composed of a natural seawater bacterial consortia exposed to crude oil-derived compounds dissolved in sterile seawater with three sets of controls: (1) sterile seawater with oil-derived water-soluble compounds; (2) a natural seawater bacterial consortia amended with succinic acid, which was used as a simple carbon source instead of crude oil and; (3) an unamended natural seawater bacterial consortia. All incubation sets were supplemented with nutrients and kept in the dark at room temperature for 14 days. Samples were taken in triplicate on T=0, T=7 and T=14. Microbial community structure has been analysed using targeted sequencing of the 16S rRNA gene. Analysis of the function of the microbial community has been performed via shotgun metagenomic sequencing.