Transporting methane from gas wellheads to market provides multiple opportunities for this greenhouse gas to leak into the atmosphere. Now, an international team of researchers has taken a first step towards converting methane directly to electricity using bacteria. By doing this, methane will be utilised directly reducing the problems caused by shipping.
The researchers’ goal is to use microbial fuel cells to convert methane into electricity near the wellheads, eliminating long-distance transport. They have created a bacteria-powered fuel cell that can convert the methane into small amounts of electricity. The study was published in Nature Communications.
Microbial fuel cells convert chemical energy to electrical energy using microorganisms. They can run on most organic material, but methane causes some problems for microbial fuel cells. As bacteria using methane live in depths of ocean and are not currently culturable in the laboratory.
Therefore, the researchers created a consortium of bacteria that produces electricity where each bacterium does its portion of the job. Using synthetic biological approaches, the researchers created a bacterium like those in the depths of the Black Sea. This organism was modified such that it could be grown in the laboratory. It used methane and produced acetate, electrons and the energy enzyme that grabs electrons. The researchers also added a mixture of bacteria found in sludge from an anaerobic digester. The anaerobic bacteria produced compounds that transported electrons to an electrode.
Once electrons reached an electrode, the flow of electrons produces electricity. To increase the amount of electricity produced, the researchers used a naturally occurring bacterial genus – Geobacter. This bacterium consumes the acetate created by the synthetic bacteria that captures methane to produce electrons.
This process makes a lot of electricity for a microbial fuel cell. However, at this point that amount is 1,000 times less than the electricity produced by a methanol fuel cell.