Bacteria with a diet of metals found in dirty dishes

Microbiologists at the California Institute of Technology have discovered bacteria that feed on manganese and use metal as a source of food. Their existence was predicted more than a century ago, but no one has been found or described so far. These bacteria were discovered by a lucky chance, reports Nature.

These are the first bacteria that use manganese as a fuel source, scientists said. The amazing aspect of microbes in nature is that they can metabolize seemingly unlikely materials, such as metals, to provide energy that is beneficial to the cell.

A study of newly discovered bacteria also shows that they can use manganese to convert carbon dioxide into biomass. This process is called chemosynthesis. Previously, researchers knew about bacteria and fungi that can oxidize manganese or deprive its electrons. But they only assumed that microbes not yet identified could use this process to stimulate growth.

Dr. Leadbetter, a professor of environmental microbiology at the California Institute of Technology, discovered bacteria by chance after performing unrelated experiments using a light, chalk-like form of manganese. He left a glass jar contaminated with a substance to soak tap water in his office in Caltech. Then the scientist was engaged in another project for several months off-campus. When he returned, the can was covered with dark material.

The black coating was actually oxidized manganese formed by newly formed bacteria, which probably came from tap water itself. There is evidence that relatives of these creatures live in groundwater.

Manganese is one of the most common elements on the surface of the earth. Manganese oxides take the form of a dark lumpy substance and are common in nature. They were found in underground sediments and can also form in water distribution systems.

There is a number of literature on environmental engineering about the distribution systems of drinking water clogged with manganese oxides. But how and for what reason such material is generated remains a mystery. Obviously, many scientists believe that bacteria that use manganese to produce energy may be responsible for this process, but there is still no evidence to support this idea.

Dr. Leadbetter, Professor of Environmental Microbiology at Caltech

The new discovery helps researchers better understand the geochemistry of groundwater. It is known that bacteria can decompose pollutants in groundwater, a process called bioremediation. At the same time, several key organisms “restore” manganese oxide. This means that they give him electrons, just like people use oxygen from the air. Scientists are wondering where manganese oxide comes from.

Discovered bacteria can produce it. Their lifestyle, which also serves to supply other microbes with what they need to carry out “beneficial and desirable” reactions, said Dr. Leadbetter.