Biological complexity: bacteria harvest electrons for food (Introduction)

by David Turell , Tuesday, November 05, 2019, 18:36 (1628 days ago) @ David Turell
edited by David Turell, Tuesday, November 05, 2019, 18:45

A very specialized complex protein does the transfer:

https://phys.org/news/2019-11-microbes-harvest-electrons.html

"Bacteria don't have mouths, so they need another way to bring their fuel into their bodies. New research from Washington University in St. Louis reveals how one such bacteria pulls in electrons straight from an electrode source.

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"'I was excited when we found that these phototrophic bacteria use a novel processing step to regulate the production of key electron transfer protein involved in this process," 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."

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"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.

Bose and her collaborators, including Robert Kranz, professor of biology, showed that the naturally occurring strain of Rhodopseudomonas palustris TIE-1 builds a conduit to accept electrons across its outer membrane. 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.

"Extracellular electron uptake, or EEU, can help microbes to survive under nutrient-scarce conditions."

Comment: The usual question arises. How did a chance evolutionary process find such a useful complex protein? By design.