Electricity from Bacteria

Each year, wastewater treatment plants use enormous amounts of energy to rid water from our homes and businesses of waste products. Much of this waste is actually organic matter which itself is a form of energy. What if this stored energy could be harnessed as a useful source of power?

Enter the bacterial strain known as Geobacter sulfurreducens. First discovered along the muddy banks of the Potamic River in 1987, Geobacter is capable of producing electricity as a part of its normal metabolism. Since its discovery, it has been modified in the lab to become even more efficient at electricity production. The challenge now at hand is to harness this ability for industrial applications.

One such potential application is wastewater treatment. BecauseGeobacter works best under anaerobic – no oxygen – environments, it grows well in large sewage-treatment plants – and can actually use the organic matter that makes up sewage waste as an energy source, converting it to carbon dioxide, clean water, and electricity.

Several different research groups, academic and commercial, are working on this problem. The Israeli company Emefcy (the name derives from the initials MFC – microbial fuel cell) reports the ability to produce 1 kilowatt/hour of electricity from 1 kilogram of organic waste. If scaled up successfully, this translates to megawatts of electricity/hour – with clean water produced as a byproduct.

The biotechnology revolution took off in the 1970s when scientists learned how to engineer bacteria to produce human insulin. In the intervening forty years, dozens of lifesaving therapeutics have been produced using these humble organisms. The next forty years may see bacteria play a pivotal role in another revolution – clean energy.