Research on Geobacter’s Nanowires Opens Door for Microbial Fuel Cell Development

Michigan State University researchers have discovered that Geobacter bacteria’s conductive pili or nanowires control the electrical activity during the cleanup process of nuclear wastes such as uranium contamination and other lethal metals.

The researchers’ findings, which can be enhanced and patented, are reported in the current edition of the Proceedings of the National Academy of Sciences.

According to Gemma Reguera, who serves as AgBioResearch scientist at Michigan State University, the research findings revealed that nanowires or hair-like segments on the outside of the bacteria act as a major catalyst in the reduction of uranium. Geobacter bacteria can play a significant role to clean up contaminated sites across the globe, Reguera said. Uranium impurities can be generated at any stage in the nuclear fuel production, and this novel method safely thwarts its mobility and the risk for exposure, she added.

Reguera further said that the nanowires perform nature's version of electroplating process with uranium. They efficiently immobilize uranium, thus stopping it from seeping into groundwater, she added. They also guard Geobacter and enable the microorganism to survive in an adverse environment, she said.

During the demonstration at a uranium mill tailings site located in Rifle, Colorado, the scientists dispensed acetate into the contaminated groundwater. The addition of acetate, which is Geobacters' favorite food, triggers the growth of the already existing Geobacter community in the soil, thus resulting in the removal of uranium, Reguera said.

Reguera team was able to genetically design a Geobacter strain with improved nanowire production. The altered version enhanced the microorganism’s capability to immobilize uranium in proportion with the count of nanowires, while simultaneously enhancing its feasibility as a microbial fuel cell.