The discovery of an archaeon that degrades ethane could help generate bioethane

Ethanoperedens thermophilum in red and its symbiote Desulfofervidus auxilii in green
An article published in the journal “mBio” reports the discovery of an archaeon that feeds on ethane in hydrothermal vents at the bottom of the Guaymas Basin, in the central area of ​​the Gulf of California. A team of researchers led by Gunter Wegener of the Max Planck Institute for Marine Microbiology proposed the name Ethanoperedens thermophilum for this archaeon that lives in symbiosis with a bacterium already known for which Wegener and his collaborators proposed the name Desulfofervidus auxilii. The interest in these microorganisms goes beyond biological curiosity because the metabolic process that degrade ethane is reversible, and this means that other similar archaea could transform carbon dioxide into ethane. This would lead to their use for the production of ethane, the second most common component of natural gas after methane with 15%.

In hydrothermal vents existing at considerable depths live microorganisms with metabolisms well adapted to those conditions that can be extreme. There are species that generate methane and others that consume methane but others have been discovered with metabolisms that include other alkanes. This led to the emergence of forms of symbiosis between very diverse microorganisms, in fact they’re species of bacteria in symbiosis with species of archaea, single-celled microorganisms without a nucleus.

There are plenty of hydrothermal vents in the Guaymas Basin, to the point that Gunter Wegener called it a natural laboratory full of new species. That’s due to the fact that very hot fluids come out of the seabed providing heat and various compounds that attract many different species. At a depth of about 2000 meters his team discovered a new symbiosis between an archaeon and a bacterium. Desulfofervidus auxilii was already mentioned in an article published in March 2016 in the journal “Environmental Microbiology” in a symbiosis with another archaeon, in that case in a metabolism with methane at the center studied by a team with some members in common with the one that carried out the new research. Instead, Ethanoperedens thermophilum is a new species.

The bottom photo (Courtesy Woods Hole Oceanographic Institution. All rights reserved) shows a phase of marine research operations with the submarine ALVIN on the seabed and its arm used to take sediment samples. The microorganisms mats are visible in white-orange color.

The top image (Courtesy Max Planck Institute for Marine Microbiology/Cedric Hahn. All rights reserved) shows Ethanoperedens thermophilum in red and its symbiote Desulfofervidus auxilii in green seen under a laser-scanning microscope.

The researchers managed to cultivate these microorganisms in laboratory, a step far from granted when it comes to organisms that live in environments that are difficult to reproduce. This success is very useful in studying the details of the archaeon’s ethane degradation process and in obtaining its DNA for sequencing.

An important discovery is that the ethane degradation by the archaeon Ethanoperedens thermophilum is reversible. This means that there may be other archaea of the same genus or at least related to it with a metabolism that generates ethane starting from carbon dioxide. Gunter Wegener’s team is already looking for other archaea with this ability, which would be useful for producing at least part of the natural gas in a sustainable way.

A phase of marine research operations with the submarine ALVIN on the seabed

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