Isolation of alkane-degrading bacteria from deep-sea Mediterranean sediments

Aims: To isolate and identify alkane-degrading bacteria from deep-sea superficial sediments sampled at a north-western Mediterranean station. Methods and Results: Sediments from the water/sediment interface at a 2400 m depth were sampled with a multicorer at the ANTARES site off the French Mediterranean coast and were promptly enriched with Maya crude oil as the sole source of carbon and energy. Alkane-degrading bacteria belonging to the genera Alcanivorax, Pseudomonas, Marinobacter, Rhodococcus and Clavibacter-like were isolated, indicating that the same groups were potentially involved in hydrocarbon biodegradation in deep sea as in coastal waters. Conclusions: These results confirm that members of Alcanivorax are important obligate alkane degraders in deep-sea environments and coexist with other degrading bacteria inhabiting the deep-subsurface sediment of the Mediterranean. Significance and Impact of the Study: The results suggest that the isolates obtained have potential applications in bioremediation strategies in deep-sea environments and highlight the need to identify specific piezophilic hydrocarbon-degrading bacteria (HCB) from these environments.