Shock to the system: bugs in our guts churn out electricity


Shock to the system: bugs in our guts churn out electricity

Hundreds of types of bugs produce electrical charges that can make us fall ill, scientists have discovered

Sarah Knapton

Bacteria are known to play a crucial role in the human gut, but scientists have discovered they hold a shocking secret: they produce electricity.
US researchers have found that hundreds of types of bugs produce electrical charges that can make us fall ill. Previously bacteria that produce electricity have been found in extreme environments, deep within mines or at the bottom of lakes, where they use the ability to take in nutrients. But scientists have noticed a similar process occurs in the gut.
Some electro-bacteria are known to be responsible for human illnesses, such as gangrene and listeria and those that cause hospital-acquired infections and food-related sicknesses. “The fact that so many bugs that interact with humans – as pathogens or in probiotics, or in our microbiota or involved in fermentation of human products – are electrogenic, had been missed before,” said Dan Portnoy, professor of molecular and cell biology at the University of California, Berkeley.
“It could tell us a lot about how these bacteria infect us or help us have a healthy gut.”
While animals and plants use oxygen to create the chemical reactions needed to fuel their cells, bacteria in airless environments must find an alternative. Underground, that can often be minerals such as iron or manganese, which must “breathe” to survive. To grab those substances, bacteria make tiny electrical currents that allow electrons to be swapped with the minerals.
The same electrical chain reaction has been found in the human gut, also an oxygen-free environment.
“We think that the conventionally studied mineral-respiring bacteria are using extracellular electron transfer because it is crucial for survival, whereas these newly identified bacteria are using it because it is ‘easy’,” said Sam Light, a postdoctoral fellow at the university and first author of the study.
Scientists think the discovery will be useful to researchers who are trying to create “living batteries” from microbes. If harnessed, it could allow green energy to be created from bacteria in waste treatment plants.
Caroline Ajo-Franklin, a scientist from the Lawrence Berkeley National Laboratory, measured the current from streams of gut bacteria and found they produced up to 500 microamps, enough to run a tiny motor. Light also found that lactobacilli, bacteria crucial to the production of cheese, yoghurt and sauerkraut, also produce electricity, and has theorised that they may play a role in producing the taste of cheese and sauerkraut.
“This is a whole big part of the physiology of bacteria that people didn’t realise existed, and that could be potentially manipulated,” he said.
The research was published in the journal Nature.
– © The Daily Telegraph

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