Purple phototrophic bacteria -- which can store energy from light -- when supplied with an electric current can recover near to 100 percent of carbon from any type of organic waste, while generating hydrogen gas for use as fuel.
According to the authors, this was the first reported use of mixed cultures of purple bacteria in a bioelectrochemical system -- and the first demonstration of any phototroph shifting metabolism due to interaction with a cathode.
Capturing excess CO2 produced by purple bacteria could be useful not only for reducing carbon emissions, but also for refining biogas from organic waste for use as fuel.
However, Puyol admits that the group's true goal lies further ahead.
"One of the original aims of the study was to increase biohydrogen production by donating electrons from the cathode to purple bacteria metabolism. However, it seems that the PPB bacteria prefer to use these electrons for fixing CO2 instead of creating H2.
"We recently obtained funding to pursue this aim with further research, and will work on this for the following years. Stay tuned for more metabolic tuning."