New Microbe Discovery Turns Crude Oil Into Methane

Epifluorescence microscopy picture of Methanoliparia cells attached to a droplet of oil. The white scale bar represents a length of 10 micrometers. (Max Planck Institute for Marine Microbiology)

(CN) – Scientists have discovered a microbe that has the potential to transform long-chain hydrocarbons found in crude oil into methane gas, according to a study published Tuesday.

The study, published in the journal mBio, contains environmental data, genomes and the first images of the microbe Methanoliparia, an archaeon that uses a process called “alkane disproportionation” to split oil into methane and carbon dioxide.

Crude oil and natural gas seeps naturally from Earth’s seabed, gradually moving through fractured rocks and sediments on their way towards the ocean floor where they are found spilling out of the ground.

The hydrocarbons found in crude oil and natural gas are an important energy source for subsurface microorganisms in the deep ocean, including archaea microbes.

Scientists with the Max Planck Institute for Marine Microbiology and the MARUM Centre for Marine Environmental Sciences said in a statement Tuesday that the split is thought to require a complex process involving two distinct organisms, archaea and bacteria.

The study’s lead author, Rafael Laso-Pérez, said that the discovery of the microbe Methanoliparia reveals for the first time another oil breakdown process.

“This is the first time we get to see a microbe that has the potential to degrade oil to methane all by itself,” Laso-Pérez said.

Scientists collected sediment samples from the Gulf of Mexico at the Chapopote Knoll, an oil and gas seep nearly two miles below the surface, and studied them at a lab in Bremen, Germany.

Genomic analysis revealed that Methanoliparia contains unique enzymes that can break down oil without using oxygen.

Researcher Gunter Wegener, who initiated the study, said that Methanoliparia uses hydrocarbon-degrading tools developed by its archaea predecessors, including methanogens which form methane as a metabolic product.

“The new organism, Methanoliparia, is kind of a composite being,” Wegener said. “Microscopy shows that Methanoliparia cells attach to oil droplets. We did not find any hints that it requires bacteria or other archaea as partners.”

Laso-Pérez said that Methanoliparia was detected in the DNA databases of oil reservoirs in oceans around the world.

Although it is plentiful, scientists are still unable to grow the microbe in a lab, which Wegener said is the next step to unlock the microbe’s potential to address issues such as climate change.

“It will enable us to investigate many more exciting details.” Wegener said. “For example, whether it is possible to reverse the process, which would ultimately allow us to transform a greenhouse gas into fuel.”

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