“In the current biogas installations, methane is produced by microorganisms and subsequently burnt, which drives a turbine, thus generating power. Less than half of the biogas is converted into power, and this is the maximum achievable capacity. We want to evaluate whether we can do better using microorganisms,” said Cornelia Welte, a microbiologist at Radboud University, Nijmegen, Netherlands.
In this new study that was able to produce living batteries, Welte and her colleagues obtained a sample of methane-gobbling microbes known as Anaerobic methanotrophic (ANME) archaea, specifically the Candidatus Methanoperedens nitroreducens, also known as ANME 2d.
They made them grow in an environment without oxygen, where the only electron donor was methane. Near the microbial community, a metal anode set at zero voltage was placed, efficiently producing an electrochemical cell that is primed to generate a current.
“We create a kind of battery with two terminals, where one of these is a biological terminal and the other one is a chemical terminal,” explained microbiologist Heleen Ouboter who is also from Radboud University. “We grow the bacteria on one of the electrodes, to which the bacteria donate electrons resulting from the conversion of methane.”
After their analysis of the methane conversion to carbon dioxide and the measurements of the fluctuating currents which reached as high as 274 milliamps per square centimeter, the team opined that a third of the current was attributed to the methane breakdown. This means that 31 percent of the energy in the methane had been converted into electrical power, which makes it comparable with some power stations.
With more experiments, it could be possible to use these microbes in creating more efficient energy sources, according to the study authors.
However, they also deem it best for the world to stop using fossil fuels that have been producing methane, which is so much worse than carbon dioxide.Whizzco