Electricity-generating bacteria found in human intestines
Electrogenic bacteria have so far been found in exotic environments such as mines and lake beds, but scientists have missed another, equally exotic source of these bacteria – the human gut.
Researchers at the University of California, Berkeley, have discovered that the bacterium that causes diarrhea, Listeria monocytogenes, produces electricity using a completely different technique than other known electrogenic bacteria. Moreover, hundreds of other speciesoIn bacteria, it uses the same method.
Many of these bacteria are part of the human gut microbiome, and quite a few of them, like Listeria monocytogenes, ktora causes listeriosis, is a pathotworcza. Bacteria that cause gangrene – Clostridium perfringens – and fecal streptococci associated with infections in hospitals – Enterococcus faecalis – and someore pathotworic bacteria Streptococcus, roThey also generate electricity. Other electrogenic bacteria, such as Lactobacillus, play an important role in yogurt fermentation, and many of them are probiotics.
The findings were published in the journal „Nature”.
– Many microorganismsow, whichore interact with humans, zaroboth as pathogens and probiotics, being part of our microflora or involved in product fermentationoin humans, are electrogenic. This fact was overlooked earlier – said Dan Portnoy, a University of California professor specializing in molecular biology and comorkowa. – This can tell us a lot about how these bacteria infect us or help us maintain gut health – added.
The discovery is also good news for those whooAccording to researchers probers to create live batteries of microbialow. Such "green" Bioenergy technologies can, for example, generate electricity from bacteria in waste treatment plantsow.
Bacteria produce electricity for the same reason that ktore we breathe oxygen: for electron removalow arising during metabolism and supporting energy production. Animals and plants transfer electrons to oxygen found inside mitochondriaoin every comorce, but bacteria living in anaerobic environments-including our intestines, but also in alcohol fermentation vats or mines-must find another electron acceptorow. In geological environments, these are often minerals outside of comork – for example, iron or manganese. In a sense, these bacteria "they breathe" iron or manganese.
Electron transferow of the comorki to the mineral requires a cascade of special chemical reactions, called. externalcomork electron transfer chainoIn, whichory carries electrons in the form of a weak electric current. Someoers have used this chain to create a battery of.
A newly discovered mechanism of electron transferow is actually simpler and seems to be used by bacteria only when necessary, perhaps when oxygen levels are low. So far, it has been detected in bacteria with a single cell walloclassified as Gram-positive bacteria, whichoThe bacteria live in an environment rich in flavins – derivatives of vitamin B2.
– It seems that the structure of the comorkowa of these bacteria and the vitamin-rich ecological niche theyorą occupy, greatly facilitates electron transferoin with the comorki. As a result, we believe that conventionally studied bacteria using minerals, use extracomork electron transferow because it is crucial to their survival, while those newly identified use it because it is simple – explained Sam Light, head of theowny author of the publication.
To test how robust the system is, Light teamed up with Caroline Ajo-Franklin of Lawrence Berkeley National Laboratory, whoora is studying the interactions between living microorganisms and inorganic materials for possible applications in carbon capture and sequestration and energy generation.
Ajo-Franklin used an electrode to measure electrical current, whichory flows from bacteria. It turned out to have an intensity of up to 500 microamperesow. They actually produce so much electricity – about 100,000 electronsow per second per comorka – like other known electrogenic bacteria.
Light is particularolnie intrigued by the presence of this mechanism in Lactobacillus, bacteria necessary for cheese, yogurt and sauerkraut production. Perhaps, as suggested by the electron transportow plays a role in the taste of cheese and sauerkraut.
– This is a large part of the bacteria’s physiology, o ktohe existence of which people did not realize. These bacteria can potentially be manipulated – admitted Light. Light and Portnoy stress that further research is needed to answer questions about how and why these bacteria developed such a unique system?