Sparking stomachs: batteries from bacteria

Electricity generating bacteria are not a new discovery. They have previously been known to exist in hard to reach places such as at the bottom of lakes and mines. Given that we already knew such bacteria existed, what makes it newsworthy?

Researchers at the University of California, Berkeley, have found that the production of electricity is also a property of more common types of bacteria – the bacteria found in your gut.

Listeria monocytogenes is a common type of pathogenic bacteria found in the gut, which causes diarrhoea and other complications. It uses an alternative method of electricity production to that of already known electrogenic bacteria. This other mechanism of producing electricity is also used by many other types of common gut bacteria, such as clostridium perfringens and enterococcus faecalis (both of which are found in most healthy individuals but can sometimes have dangerous effects, ranging up to gangrene and meningitis).

Simply put, gut bacteria produce electricity through ‘breathing’. Humans respire, using oxygen as the electron carrier to remove the electrons produced whilst cells metabolise. Bacterial cells must lose their electrons to something to support the cells’ energy production, in a similar fashion. In the absence of oxygen, the electrons are passed onto vitamins and minerals, creating a current, explaining why they can be found in the gut and in mines.

What can we take from this new discovery?

Firstly, the body’s microbiome is extremely important in determining the state of our wellbeing. Our microbiomes make up between 1 and 2 per cent of our body’s mass. Despite knowing that the average healthy human has more bacterial cells than human cells, the complexity, variation and role that our body’s microflora plays in our wellbeing is largely unknown. Knowing that these gut bacteria produce electricity may help to explain some medical mysteries. The bacteria in our guts is thought to have a heavy influence on both an individual’s physical and mental health, affecting things such as anxiety and depression levels and insulin sensitivity. Understanding just how the bacteria in your gut controls these things still requires more research, but the University of California’s new findings are a promising step in the right direction.

In terms of bacteria as an energy source, although progress has been made, harnessing electricity from gut bacteria is still in its early stages. Work has already been carried out in synthesising the molecule DSFO+, which aids the metabolism of bacteria and heightens the production of electricity (rather than altering the makeup of the bacteria itself). However, there is hope for advancements in the technology of microbial fuel cells, to make them more efficient and widen their applications. They are already being utilised to improve wastewater treatment systems and solar cells. Keep an eye out for bacteria-powered gadgets in the (slightly distant) future.

Image credit: PublicDomainPictures via Pixabay

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