Metagenomics reveals the high PAH-degradation potential of abundant uncultured bacteria from chronically-polluted subantarctic and temperate coastal marine environments

LOVISO, C.L.; LOZADA, M.; GUIBERT, L.M.; MUSUMECI, M.A.; SARANGO CARDENAS, S.; KUIN, R.V.; MARCOS, M.S.; DIONISI, H.M.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 119 p. 411 - 424

1364-5072

Aims: To investigate the potential to degrade polycyclic aromatic hydrocarbons (PAHs) of yet-to-be cultured bacterial populations from chronically-polluted intertidal sediments. Methods and Results: A gene variant encoding the alpha subunit of the catalytic component of an aromatic ring-hydroxylating oxygenase (RHO) was abundant in intertidal sediments from chronically-polluted subantarctic and temperate coastal environments, and its abundance increased after PAH amendment. Conversely, this marker gene was not detected in sediments from a non-impacted site, even after a short-term PAH exposure. A metagenomic fragment carrying this gene variant was identified in a fosmid library of subantarctic sediments. This fragment contained five pairs of alpha and beta subunit genes and a lone alpha subunit gene of oxygenases, classified as belonging to three different RHO functional classes. In silico structural analysis suggested that two of these oxygenases contain large substrate-binding pockets, capable of accepting high molecular weight PAHs. Conclusions: The identified uncultured microorganism presents the potential to degrade aromatic hydrocarbons with various chemical structures, and could represent an important member of the PAH-degrading community in these polluted coastal environments. Significance and Impact of Study: This work provides valuable information for the design of environmental molecular diagnostic tools and for the biotechnological application of RHO enzymes.