Iron-oxidizing bacteria can now grow without iron- they can use electricity instead. This is the conclusion reached by a team of scientists at the the BioTechnology Institute at the University of Minnesota – Twin Cities, led by Daniel Bond.
The method, which they developed, is called electrochemical cultivation.
Bacteria are supplied with electrons that are used for respiration. The authors point out that since bacteria can synthesize everything they need only by using electricity, this opens dozens of possibilities for converting renewable energy into biofuel.
The electrons are taken off dissolved iron (Fe II) by the iron oxidizers, which result in rust formation. Iron-oxidizing bacteria are very common. They contribute to corrosion and have a major role in the global cycling of iron, but they are still very difficult to study under laboratory conditions.
The team hypothesized that iron oxidation takes place on the surface of these bacteria.
They used marine iron oxidizer, Mariprofundus ferrooxydans PV-1, and nutrients, which were added to an electrode. The electrons that this electrode provides were at the same energy level as Fe (II). If the hypothesis was proven, then bacteria should be able to grow.
The experiment proved to be successful. The bacteria multiplied, which supported the theory that they grow using absorbed electrons, which helped them capture carbon dioxide. This capturing is the key to converting electricity into biofuel, according to Bond.