These microbes breathe methane and convert it into electricity – researchers have found a new way to extract energy
Among greenhouse gases, methane is the most harmful because it can further exacerbate the climate crisis. In our atmosphere, it “traps” heat at least 25 times more efficiently than carbon dioxide.
It is not very efficient at combustion – more than half of the natural gas energy can be converted into electricity.
In an attempt to capture more electrons from each part of methane, Dutch scientists have studied a more unconventional form of power plant – one that you would need a microscope to see.
“It can be very useful in the energy sector. In current biogas plants, methane is produced by microorganisms, which then burn, drive a turbine and generate electricity. Less than half of biogas is converted into energy and this is the maximum achievable capacity. “We want to assess whether we can do better with microorganisms,” said Cornelia Velte, a microbiologist at the University of Redbud.
The main focus of their research was one type of archaea, a bacterium-like microbe distinguished by its special ability to survive in strange and harsh environments; Among them, methane can decompose in an oxygen-deprived environment.
This particular type, called anaerobic methanotrophic arches (ANMEs), performs this metabolic trick by loading electrons into a chain of electrochemical reactions, using any metal or non-metals outside their own cells, or transmitting them to other species in their own environment.
The genus ANME, named Methanoperedens, was first described in 2006 and found to oxidize methane with little help from nitrates, and in its own environment, in wetlands impregnated with Dutch fertilizers.
Attempts to remove electrons from this process taking place in microbial fuel cells have resulted in the generation of low voltages, without any apparent confirmation of exactly what processes may be behind this conversion.
If these arches ever find promising to be used as methane-absorbing energy cells, they will definitely need some clever approach.
Complicating matters further is the fact that Methanopereden are not easily cultured microbes.
Therefore, Welte and his colleagues collected samples of microbes that were known to dominate these methane-absorbing arcs, and then raised them in an oxygen-free environment where the only electron donor was methane.
In the vicinity of this colony, they also placed a metal anode under zero voltage, thus creating an efficient electrochemical cell needed to generate electricity.
“We have created a kind of battery with two terminals, one of which is a biological terminal and the other a chemical one. “We grew bacteria on one of the electrodes, to which these bacteria transferred electrons from methane conversion,” said Ellen Ubotter, a microbiologist at the University of Redbudd.
After studying the conversion of methane to carbon dioxide and measuring fluctuating current that rose as high as 274 milliamperes per square centimeter, the researchers concluded that just over a third of the current must have been directly related to methane decay.
In terms of efficiency, 31 percent of methane energy is converted into electricity, making it equal to the efficiency of some power plants.
By refining this process, high-efficiency, biogas-powered live batteries can be created that will draw more energy from each goji of gas and reduce the need for methane to be piped over long distances. This is quite important, as the efficiency of some methane power plants is only about 30 percent.
People must find ways to get rid of their dependence on fossil fuels.
In addition to technological application, finding a smart way to simply decompose this greenhouse gas in the environment will not be bad either.
The research was published in Frontiers in Microbiology.