Bacteria normally found 30km above the earth have been found to be efficient generators of electricity.
Bacillus stratosphericus and B. altitudinis are microbes found in high concentrations in the stratosphere – although the Newcastle University team rather more prosaically, isolated them from a nearby river after they were brought down to earth as a result of atmospheric cycling processes.
Microbial fuel cells use bacteria to convert organic compounds directly into electricity by a process known as bio-catalytic oxidation.
A biofilm – or ‘slime’ – coats the carbon electrodes of the MFC and as the bacteria feed, they produce electrons which pass into the electrodes and generate electricity.
The team tested the power-generation of 75 different species of bacteria using a Microbial Fuel Cell (MFC). And by selecting the best, they were able to create an artificial biofilm, doubling the electrical output of the MFC from 105 Watts per cubic metre to 200 Watts per cubic metre.
While still relatively low, this would be enough power to run an electric light, they say, and could provide a much needed power source in parts of the world without electricity.
“What we have done is deliberately manipulate the microbial mix to engineer a biofilm that is more efficient at generating electricity,” says professor of marine biotechnology Grant Burgess.
“This is the first time individual microbes have been studied and selected in this way. Finding B. altitudinis was quite a surprise but what it demonstrates is the potential of this technique for the future – there are billions of microbes out there with the potential to generate power.”