Sun. Jul 21st, 2019

How Microbes Utilize Electrons to Fix Carbon Dioxide

New research done at the Washington University elaborates the cellular processes which allow a solar microbe to consume electricity and transferring the electrons to fix carbon dioxide in order to fuel its growth.

Led by an assistant professor of biology, Arpita Bose and Dr. Michael Guzman, a team at the Washington University explained how a strain of Rhodopseudomonas palustris uses electrons from conductive materials such as metal oxides or rust. Their research elaborates the cellular sinks, where electrons ate from the electricity by the microbes, are dumped.

Bose said, “It clearly shows for the first time how this activity — the ability for the organism to eat electricity — is connected to carbon dioxide fixation,”

“R. palustris strains can be found in wild and exotic places like a rusty bridge in Woods Hole, Massachusetts where TIE-1 was isolated from,” Bose also said. “Really, you can find these organisms everywhere. This suggests that extracellular electron uptake might be very common.”

Guzman further added: “The main challenge is that it’s an anaerobe, so you need to grow it in an environment that doesn’t have oxygen in order for it to harvest light energy. But the flip side to that is that those challenges are met with a lot of versatility in this organism that a lot of other organisms don’t have.”

The researchers explained that the electrons from electricity would enter into proteins into the membranes that are essential for photosynthesis. Shockingly, when the ability of a microbe to fix carbon dioxide was deleted, a 90% decrease in its ability of electricity consumption was observed.

“It really wants to fix carbon dioxide using this system,” Bose added. “If you take it away — this innate ability — it just doesn’t want to take up electrons at all.”

Bose said that the reaction resembled a rechargeable battery.

“The microbe uses electricity to charge its redox pool, storing up the electrons and making it highly reduced,” Bose explained. “To discharge it, the cell reduces carbon dioxide. The energy for all this comes from sunlight. The whole process keeps repeating itself, allowing the cell to make biomolecules with nothing more than electricity, carbon dioxide and sunlight.”

“We hope that this ability to combine electricity and light to reduce carbon dioxide might be used to help find sustainable solutions to the energy crisis,” wished Bose.