Bacteria batteries to produce electricity

Ten Bielefeld students have set their sights on constructing a bio-battery. They want to make use of the bacteria Escherichia coli to convert glucose into energy. An increasing demand for sources of alternative energy, environmental pollution caused by conventional batteries and the phasing out of nuclear energy in Germany encouraged the Bielefeld iGEM team to develop a bio-battery (microbial fuel cell - MFC), which directly transforms bacteria into energy.

Batteries such as these work in the same way as conventional batteries, but with one difference. The MFC consists of two separate units, the anode and the cathode components, just like the batteries now in current household use. A partly permeable membrane separates the two areas.

In contrast to conventional batteries, however, there are bacteria in the anode area of the bio-battery instead of electrolytes. These break down substrates, in this case glucose, in a metabolic process. This produces electrons that after starting from the anode are finally delivered in an external loop to the cathode. The external circuit is then the one with the battery-powered application, for example, for lights or small motors. In this way, bacteria can produce electric energy. Due to their simple construction they can be used in regions where there is shortage of electricity, for example, such as in developing countries.

The Bielefeld students produce electricity by using a self-made bio-battery. Photo: iGEM team 2013

In the case of bio-batteries, the more nourishment the bacteria receive the more energy they produce. What is more, in theory bacteria are an inexhaustible source of energy as they multiply quickly when supplied with substrates.

In the laboratory, the Bielefeld students are investigating various bacterial organisms and their genetic components. Through the combination of differing genes it is possible to optimise the organism Escherichia coli with a view to produce electricity more efficiently. The students have isolated various genes that serve to carry the electrons and begun to construct a suitable apparatus for the production of electricity. The students are taking part in iGEM competition and would like to have an optimised bio-battery for small-scale use developed by the time the preliminary European round of the iGEM has been decided.