Scientists discover how microbes acquire electricity in making methane
In a new study, the Stanford team demonstrates for the first time how methanogens obtain electrons from solid surfaces. The discovery could help scientists design electrodes for microbial "factories" that produce methane gas and other compounds sustainably.
"There are several hypotheses to explain how electrons get from an electrode into a methanogen cell," said Stanford postdoctoral scholar Jörg Deutzmann, lead author of the study. "We are the first group to identify the actual mechanism."
The study is published in the current issue of the journal mBio.
"The overall goal is to create large bioreactors where microbes convert atmospheric carbon dioxide and clean electricity from solar, wind or nuclear power into renewable fuels and other valuable chemicals," said study co-author Alfred Spormann, a professor of chemical engineering and of civil and environmental engineering at Stanford. "Now that we understand how methanogens take up electricity, we can re-engineer conventional electrodes to deliver more electrons to more microbes at a faster rate."
The study also provided new insights on microbially influenced corrosion, a biological process that threatens the long-term stability of structures made of iron and steel.
"Biocorrosion is a significant global problem," Spormann said. "The yearly economic loss caused by this process is estimated to be in the $1 billion range."
Methane from microbes
Methane is an important fuel for heating, transportation, cooking and generating electricity. Most methane comes from natural gas, an abundant fossil fuel extracted from wells. However, burning natural gas emits carbon dioxide, which accelerates global warming.
Methanogens offer a promising alternative. These single-celled organisms resemble bacteria but belong to a genetically distinct domain called Archaea.