Polycyclic aromatic hydrocarbons (PAHs) comprise a vast family of compounds found in crude oil. These compounds can be highly toxic, and negatively impact biological processes such as DNA replication and transcription. PAH congeners that possess a ‘bay’ or ‘fjord’ region are particularly susceptible to partial oxidation and subsequent intercalation with double-stranded DNA, inducing cell death by precluding access to the affected sequences. Therefore, it is vital to understand the environmental fate of these molecules after oil spill events, particularly in coastal environments where flora, fauna, and humans may be exposed. Benzo[a]pyrene (B[a]P) is a high molecular weight pentacyclic molecule with a prominent bay region that has been shown to be degraded by microbes under specific conditions; however, little attention has been paid to its next larger siblings, the dibenzopyrenes. This group of congeners is hexacyclic, and, depending on conformation, may have one or multiple bay regions. These isomers are of particular interest as recent technology has enabled the resolution of individual congeners from a mixed solution, heretofore an infeasible proposal. In this study, a particular microbial species (<i>Mycobacterium vanbaalenii</i> strain PYR-1) was exposed to a more labile PAH, phenanthrene, to develop analytical methods and optimal growth conditions for higher-order PAH degradation. Using these optimal growth conditions, <i>M. vanbaalenii</i> was then incubated with the higher molecular weight dibenzopyrenes to determine degradation kinetics and byproducts. Cyrofluoresence spectroscopy was used to analyze fractions collected by HPLC separation. Additionally, bacterial isolates collected from sediment from the Chandeleur Islands were screened for PAH degradation in order to find novel hydrocarbon degrading microbial species.

Microbial degradation of polycyclic aromatic hydrocarbons at ambient near-surface coastal conditions

2019 Spring National Meeting

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