Highly reduced compounds
Highly reduced compounds will release energy when they react with a suitable electron acceptor (redox-reaction). Therefore one often refers to highly reduced compounds as energy-rich. The energy is either released to the (abiotic) environment or supplying organisms with energy for their metabolism.
The cycling between ferrous and ferric iron in bioleaching is based on the fact that:
- Metal sulfides are highly reduced in comparison to Fe2+
- Fe2+ is highly reduced in comparison to Fe3+