Researchers Achieve Slightly More Efficient Transfer of Current from Bacteria to Electrode

In the last few years, scientists have sought to acquire the electrical current that bacteria produce through their own metabolism. However, to date, it has not been possible to transfer the current from the bacteria to a receiving electrode efficiently.

Presently, scientists from institutions including Lund University have attained a slightly more efficient transfer of electrical current. Fulfilling the requirement for renewable and sustainable energy is one of the greatest challenges of the society. There is an increasing interest toward one such potential energy source—bacteria.

We pick up electrons from the bacterium and transfer them to an electrode. This enables us to obtain an electrical current from the bacteria in real time, while they are eating, as it were. This study is a breakthrough in our understanding of extracellular electron transfer in bacteria.

Lo Gorton, Professor, Department of Chemistry, Lund University

Extracellular electron transfer is nothing but the current that can be produced by bacteria outside of their own cell. The challenge faced when trying to tap this energy is the need to create a molecule that can penetrate through the bacterium’s thick cell wall to recover the electrons present there more efficiently. For this reason, in the present study, the scientists developed an artificial molecule called a redox polymer. Enterococcus faecalis, a common intestinal bacterium present in animals as well as humans, is the type of bacteria investigated.

The outcomes of the study are important due to their capability with respect to future bacterial electrical energy and also because they increase the understanding of how bacteria interact with their surroundings. The bacteria themselves most likely use extracellular electron transfer to interact with other bacteria as well as with molecules.

Electron transfer could be of great significance for how the bacteria communicate with various molecules and with each other in our digestive system, but also for how nature functions in a broader perspective. It is thought today that many geological processes are bacteria-driven.

Lo Gorton, Professor, Department of Chemistry, Lund University

Insights on how bacteria function and communicate are important in several circumstances. For instance, bacteria and other micro-organisms can be used to generate biofuel, in the so-called microbial biofuel cells. The photosynthesizing bacteria are of special interest in an energy context. If the bacteria adhere to an electrode, they can produce electric energy on exposure to light. This has been demonstrated by Lo Gorton and his team in earlier studies.

In addition, profound knowledge about bacteria is valuable with regards to their promising uses such as purifying wastewater, creating molecules that are difficult to synthesize, or reducing carbon dioxide into a more usable form.