Deep-water bacteria fed clean electricity

Plants use chlorophyll photosynthesis to generate electricity, which is then stored as sugars needed for life. Plants receive energy from the sun.

Animals have a different mechanism: they take electrons from the environment using a process called chemosynthesis : oxidation-reduction reactions in which chemical compounds rich in energy are oxidized: inorganic, for example, molecular hydrogen, sulfur or organic - carbohydrates, fats, proteins paraffins, etc.

In general, so far, science has known two ecosystems: phototrophs and chemotrophs. But Japanese scientists from the University of Tokyo and the RIKEN Center for Sustainable Resource Science clearly don't like this harmony. Now they are studying the third ecosystem,which was called the "electro-ecosystem" (electrotrophs?). The Japanese are studying bacteria that can eat pure electricity.

The deep-water iron bacteria Acidithiobacillus ferrooxidans oxidize ferrous iron to ferric iron - and live off the energy received.

Japanese scientists have suggested that some deep-sea bacteria, including Acidithiobacillus ferrooxidans, can directly consume electrons from the environment instead of carrying out an oxidation reaction.

To test the hypothesis, they bred a colony of Acidithiobacillus ferrooxidans and grew it in an environment in which there was no ferrous iron, their traditional food. Instead, the bacteria were offered an electrode with a voltage of +0.4 V, carbon dioxide as a carbon source and oxygen as an electron acceptor.

The experiment showed that current flows through the electrode. Its strength depended on the number of bacteria that attached to the electrode. The destruction of bacteria by ultraviolet immediately stopped the flow of current.

An additional photochemical experiment made it possible to more accurately determine the metabolic pattern in bacterial cells and to establish that heme-containing proteins in the membrane are involved in electron transfer from the external environment.



At the next stage, the researchers intend to prove that the phenomenon of the nourishment of living beings by pure electricity exists in nature. Scientists have already discovered a geoelectric current near hydrothermal sources.

Perhaps the unique "electrotrophs" will find practical application. Imagine, you can create an entire ecosystem that will live on electricity!

Scientific workpublished in Frontiers in Microbiology .