Intestinal bacteria produce electric current from sugar

Intestinal bacteria can create an electric current, according to a new study from Lund University in Sweden. The results are valuable for the development of drugs, but also for the production of bioenergy, for example.

It is already known that bacteria can create an electric current outside their own cell, known as extracellular electron transport. This has been demonstrated and analysed in detail in some bacteria that specialise in the metabolism of metal salts.

A group of researchers has now studied extracellular electron transport in a completely different type of bacterium -- the lactic acid bacterium Enterococcus faecalis, which can be found in the gastrointestinal tract of both humans and animals.

In the study, the researchers investigated what it takes for electrons from the bacterium to be transported to an electrode. The results from their experiments show that enterococci placed at an electrode can give rise to an electric current created by the metabolism of the cell. The electrons are released when the bacterium breaks down sugar inside its cell. The actual transmission of electrons to the electrode takes place with the help of what are known as quinone molecules inside the cell membrane.

The results in the study also show that a bacterium in its natural environment, i.e. together with other bacteria and fungi, may have properties that it otherwise lacks. What happens is that two or more types of microorganisms intertwine their metabolic capacity to benefit the growth of one or both of the organisms. According to the study, this form of cooperation between microorganisms, known as synthrophy, may be linked to electron transport between the parties involved.

See:

Galina Pankratova, Dónal Leech, Lo Gorton, Lars Hederstedt. Extracellular Electron Transfer by the Gram-Positive Bacterium Enterococcus faecalis. Biochemistry, 2018; 57 (30): 4597 DOI: 10.1021/acs.biochem.8b00600

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology