Impacts of dibenzopyrenes on bacterial community isolated from Gulf of Mexico sediment

Abstract

The presence of polycyclic aromatic hydrocarbons (PAHs) in marine environments as a result of contamination is an environmental concern, especially in regions where oil spills such as the Deepwater Horizon have occurred. While numerous PAHs have been studied for their effects on microbes, the family of dibenzopyrenes has yet to be investigated. In this preliminary study, the impacts of these molecules on the community structure of a bacterial consortium isolated from oil-impacted Gulf of Mexico sediment were examined using high-throughput sequencing, demonstrating intriguing negative impacts on species diversity and abundance. While no measurable degradation of the dibenzopyrenes was observed after 28-day incubation, the abundance of known oil-degrading bacteria from orders such as Oceanospirillales, Caulobacterales, Sphingomonadales, and Nitrosococcales were shown to be enhanced. Of the five isomers of dibenzopyrene studied, dibenzo[a,h]pyrene supported the fewer number of microbial species suggesting the isomer was more toxic compared to the other isomers.

Keywords: Deepwater Horizon oil spill; bacterial consortium; bioremediation; dibenzopyrene; high-throughput sequencing; polycyclic aromatic hydrocarbon.