Some bacteries can generate electrical energy, and scientists intend to use their unusual property to create electrochemical fuel devices and wastewater treatment. As a rule, unusual bacteria exist in environments with low oxygen concentrations — for example, deep in mines and even inside living organisms. Previously, to detect them, it was necessary to grow large batches of cells and destroy them, but researchers at the Massachusetts Institute of Technology created a microfluidic chip capable of easily detecting bacteria that produce electricity.
Since these microorganisms are forced to live in places with a small amount of oxygen, they have developed a special form of respiration. Electrons are generated in their cells, which are transferred to the external environment through a process called extracellular electron transfer. Subsequently, they can be used to form a fuel cell that generates electricity.
Such bacteria in 2018 were found by scientists from the USA and Sweden. They found that Enterococcus faecalis, Listeria monocytogenes, and lactobacilli involved in the fermentation of yoghurt produce electrons in the manner described above. Then, scientists argued that the bacteria found could be used to create antibiotics against various intestinal infections.
If earlier it was necessary to grow cells to search for such bacteria and open them to study proteins, now the process takes much less time. The special MIT chip resembles an hourglass and carries the bacteria through a channel with an electric field. A phenomenon occurs in it, known as electrophoresis, when particles can stop and repel depending on the presence or absence of electrochemical activity. Thus, scientists can easily separate ordinary bacteria from those that can produce electricity.
Cullen Bui, an associate professor at MIT’s mechanical engineering department, said that recent research had revealed the possibility of the existence of a much larger spectrum of bacteria that produce electricity. Since it may not be just a small handful of microbes, but something more, the tool they create may be much more important to science than it seems.