The uncontrolled use of fossil fuels has triggered a global energy crisis, sparking interest in obtaining renewable energy sources with minimal impact on the environment. However, the recent discovery of bacteria capable of converting chemical energy into electrical suggests the emergence of a new form of green power, whose operation will be a major challenge to biotechnology in the coming years.

 What kind of bacteria can generate electricity?

Bacteria generator (producing electricity) can be found in many natural anaerobic environments and sediments of rivers, lakes or marine. These include the genus Geobacter [figure c]. These bacteria are able to breathe iron ore in the underground earth, just as we breathe oxygen, and have been doing for millions of years when there was still no oxygen on the surface of the planet. The ability of these bacteria to breathe iron oxides is of great environmental significance because it has contributed to the composition of the soil and subsoil earth is as we know it today. Now we can also use this ability to produce useful electrical energy in a clean.

The conversion of chemical energy into electricity is possible by electrochemical devices called fuel cells or batteries where the electricity is obtained from an external source of fuel is usually hydrogen or methanol. Some of the public transport vehicles in our cities are already using technology that has the safe clean water vapor as the only waste. A recent variant of this fuel cell is the microbial fuel cell (Microbial Fuel Cell, MFC). It uses microorganisms to oxidize fuel, usually organic material as present in the wastewater, and transfer electrons to an electrode (anode) connected to a cathode through a conductive material containing a resistance [figure] .
It is also possible to accommodate a fuel cell in a natural habitat to make their own natural cycles of carbon in situ provide an inexhaustible source of fuel and purchase electricity using natural microbial communities. In this case the design is called sediment fuel cell [Figure b], and requires the burial of the anode in an anaerobic sediment that would serve as the anode chamber, while the cathode be exposed in the aqueous phase covering aerobic sediment.