Energy Acquisition in Low pH Environments
Résumé
Extreme acidophiles thriving in acidic habitats are characterised by low organic substrate inputs and high concentrations in inorganic substances, in particular sulfur compounds and iron. Their strategies for harvesting energy for growth in these harsh environments are described in this chapter. An overview of the general concepts on bioenergetics is given to highlight the particular challenges faced by extreme acidophiles. Pathways involved in oxidation and reduction of iron and sulfur compounds are presented and discussed. From the available data, it is obvious that, for the same electron donor and acceptor, the metabolic pathways differ sufficiently between different prokaryotes to suggest independent origins followed by diversification and horizontal gene transfer.