Alkane biodegradation genes from chronically-polluted Subantarctic coastal sediments and their shifts in response to oil exposure

GUIBERT, L.M.; LOVISO, C.L.; MARCOS, M.S.; COMMENDATORE, M.; DIONISI, H.M.; LOZADA, M.

MICROBIAL ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2012 vol. 64 p. 605 - 616

0095-3628

We characterized alkane-degrading bacterial populations and their response to oil exposure, in sediments of a chronically-polluted Subantarctic coastal environment, by analyzing alkane monooxygenase (alkB) gene libraries. Sequences from the clone libraries were affiliated with Proteobacteria and Actinobacteria, with moderate amino acid identity to genes from isolated microorganisms (67% in average). Most sequences were most closely related to uncultured microorganisms from cold marine sediments or soils from high latitude regions, suggesting a role of environmental factors such as temperature in the structuring of this bacterial guild. Many alkB genes were shared among samples of different sites and years, and were further selected after experimental oil exposure in slurries, where the dominant alkB genes were different depending on nutritional condition. These results suggest that these genes are carried by ecologically relevant bacterial populations. Complementary information provided by 16S rRNA amplicon pyrosequencing in sediment and slurries allowed us to highlight various genera non previously associated with oil biodegradation (Spongiibacter -formerly Melitea-, Maribius, Robiginitomaculum, Bizionia, and Gillisia) or for which no alkB genes have yet been described (Oleispira, Thalassospira). These genera constitute candidates for future work involving identification of hydrocarbon biodegradation pathway genes.