Scientists have discovered that there are certain microbes that find electricity very tasty. What’s more, it turns out that these electron-eating microbes are very common. Scientists are finding them in many different places.
But how to these microbes do it? Microbes – microscopic organisms such as bacteria, protozoa, fungi – don’t have mouths, so they need another way to bring their fuel into their bodies. A new study, published November 5, 2019, in the journal mBio, reveals how one such bacteria pulls in electrons straight from an electrode source.
The molecular underpinning of this process has been difficult to unravel … This is mostly due to the complex nature of the proteins involved in this process.
According to the researchers, getting the electricity across the outer layer of the bacteria is the key challenge. This barrier is both nonconductive and impermeable to insoluble iron minerals and/or electrodes.
The study scientists showed that the naturally occurring strain of a bacteria called Rhodopseudomonas palustris TIE-1 builds a conduit to accept electrons across its outer membrane. According the the research, the bacteria relies on an iron-containing helper molecule called a deca-heme cytochrome c. By processing this protein, TIE-1 can form an essential bridge to its electron source.
The ability of these microbes to take up electrons from substances such as metal oxides – called extracellular electron uptake – can help microbes to survive under nutrient-scarce conditions.
Dinesh Gupta, a Ph.D. candidate at Washington University, is the study lead author. Gupta said:
This study will aid in designing a bacterial platform where bacteria can feed on electricity and carbon dioxide to produce value-added compounds such as biofuels.
Bottom line: Some bacteria can live on electricity. A new study investigates how they pull electrons through their outer membranes to gain energy.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.