Electrogenic and hydrocarbonoclastic planktonic biofilm at the oil-water interface as microbial responses to oil spill

The oil-water interface due to the oil spill represents a challenging environment for pelagic communities living in aquatic ecosystems. At the level of this anoxic barrier, we report the formation of a microbial hydrocarbonoclastic biofilm capable of electron transfer along the water column. This biofilm generated a membrane of surface-active compounds that allowed the spontaneous separation of electrical charges, causing the establishment of an anodic and a cathodic region and, as a result, the spontaneous creation of a liquid microbial fuel cell. Such a planktonic biofilm was connected to the underneath water column by floating filaments that could contribute to oxygen reduction at distance. The filaments revealed an unusual lipid content induced by anoxic conditions, with prominent ultrastructural features similar to the myelin of the oligodendrocyte. Furthermore, these filaments showed an interesting cross-reactivity towards different epitopes of the myelin basic protein (MBP) and Claudin 11 (O₄) of the human oligodendrocytes. The presence of a network of filaments similar to myelin suggests the probable existence of evolutionary connections between very distant organisms.

Collectively these results suggest a possible mechanism on how lake microbial communities can cope with oil spills while offering an interesting starting point for technological developments of liquid microbial fuel cell, related to the study of hydrocarbon-water interfaces.