ENW-M grant for research into electricity-powered bacteria

Purple bacteria form a distinctive group of micro-organisms. By nature, these microbes produce valuable compounds including proteins, amino acids, pigments and the dietary supplement coenzyme Q10. Like algae and plants, they grow using light and carbon dioxide. “That makes these bacteria interesting for sustainable production processes,” says Annemiek ter Heijne, Professor of Environmental Technology. “However, we still do not fully understand how to steer their growth and product formation.”

The research project is set up as a Dutch–Belgian collaboration. In Wageningen, the scientists will investigate what happens when purple bacteria are supplied not only with light and a carbon source, but also with electricity. “The electrical current acts as an additional energy source,” Ter Heijne explains. “We want to know whether this allows the bacteria to grow faster or more efficiently, and whether it influences which compounds they produce.” Electricity could, for example, shift the balance between the production of proteins and pigments.

The idea builds on existing expertise. Ter Heijne’s research group has been working for many years on systems in which micro-organisms either consume or generate electricity, for example in wastewater treatment. Previously, researchers for example succeeded in using electricity to enable micro-organisms to convert carbon dioxide into methane. The combination of electricity, light and purple bacteria, however, is new territory.

The required experiments are technically complex. The bacteria need light, while electrodes do not transmit light. “This makes it difficult to design a reactor in which bacteria receive the same amount of light and electricity throughout,” says Ter Heijne. “Some will receive more light, others more electrical energy.” Identifying the right experimental set-up is therefore a key part of the project.

In Antwerp, a second PhD candidate will focus on the bacteria themselves: how fast they grow and under which conditions they perform best. The team will also search for previously unknown variants of purple phototrophic bacteria with favourable characteristics.

The research is fundamentally oriented. The team first aims to understand what exactly happens inside purple bacteria when they receive additional energy in the form of electricity. However, the potential impact is clear. If bacteria can use green electricity to produce valuable compounds from light and air, this could offer a sustainable route for producing supplements, pigments or proteins. The current project aims to clarify how electricity influences and steers that production.

For Ter Heijne, the appeal lies largely in the unknown. “We have the opportunity to explore a completely new research topic together with a new partner,” she says. “And to investigate whether we can recover valuable compounds in a novel way, basically from almost nothing.”

The project is funded through Weave, part of the ENW-M Open Competition. Weave is an international collaboration initiative that allows researchers to submit a single joint proposal. Each national funding organisation, such as NWO in the Netherlands and the Flemish Research Foundation (FWO), finances the researchers in its own country.

The ENW-M grant from NWO supports curiosity-driven fundamental research in the exact and natural sciences. The grant provides room for high-risk ideas with the potential for major scientific impact. This year, twenty projects received funding; the Wageningen research on purple bacteria was awarded more than €400,000.