As we move towards renewable forms of energy, it is increasingly important to produce durable batteries at a low cost and in an environmentally friendly way. Like? Introducing bacteria. A species known as Shewanella oneidensis , to be more precise.

These microorganisms can survive and thrive in aerobic and anaerobic conditions with or without oxygen. In addition, microbes employ electrons in their metabolism, using energy to produce essential precursors to anchor carbon molecules, a process during which organisms take carbon from carbon dioxide and add it to an organic molecule.

Scientists are working to artificially engineer new bacteria that go a step further, using these precursor molecules to produce organic molecules like biofuels.

A team of scientists at Cornell University in the United States designed a method which facilitates the absorption of electrons in microbial metabolism for the synthesis of complex and energy-dense organic molecules from CO2 and renewable electricity. Even some microbes can do the job effectively.

“There are only a small number of microbes that can actually store renewable electricity,” explains Buz Barstow, assistant professor of biological and environmental engineering at the Faculty of Agriculture and Life Sciences, who was a key member of the research team.

Sudoku knockout

By examining the bacteria’s genes with the help of a technique they call a “sudoku knockout,” Barstow and his colleagues turned the genes off one by one to see what functions each one has.

“We found a large number of genes that we already knew about removing electrons from the cell that are also involved in electron entry,” said Barstow. “So we also discovered this whole new set of genes that no one had seen before that are needed to get electrons into the cell.”

Previous research has shown that these bacteria can serve as “living electrodes”. Other scientists have emphasized the attractiveness of this microbe due to “its extraordinary prospects for energy production, pollution treatment and biosynthesis.”

Bacteria before oxygen

Before life on Earth developed photosynthesis, the first bacteria likely used a pathway similar to that found in Shewanella oneidensis to harness the electrons from iron oxidation to extract carbon from the carbon dioxide and use it in the production of sugars, speculate Barstow and his colleagues.

The way microbes use it to convert CO2 into sugars and biofuels is very efficient, they explain. It could be easily expanded and inexpensive to operate.

“When we build a microbe that can eat electrons, which we’re doing now, it’s going to incorporate these genes,” said Barstow, who wants to start adding the genes extracted from Shewanella for Escherichia coli , a bacterium commonly used in laboratory experiments.

Engineered bacteria powered by electrons could pave the way for the use of renewable energy to produce biofuels, food and chemicals. They can also be used for carbon sequestration, scientists say.

By Sustainability Times. Article in English


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