20 The Isolation and Study of Acidophilic Microorganisms

Abstract

Publisher Summary This chapter describes the methodologies, conventional as well as molecular, used to characterize the microbial diversity existing in the extreme acidic environment of the Tinto river. These methodologies are adapted from different sources. Most of the protocols are useful for other acidic environments, although the importance of small variables in these systems (pH, temperature, redox potential, metal concentrations, etc.) should be kept in mind and optimization is strongly recommended, especially in the use of molecular ecology tools. Most of the characterized strict acidophilic micro-organisms have been isolated from volcanic areas or acid mine drainage from mining activities. The acidity in these locations is derived from the microbial oxidation of elemental sulfur. In acidic, metal-rich environments associated with mining activities, the metal and coal mining operations expose sulfidic minerals to the combined action of water and oxygen, which facilitate microbial attack, producing the so-called acid mine drainage, a serious environmental problem. The main role of acidophilic chemolithotrophic micro-organisms is to maintain a high concentration of the chemical oxidant, ferric iron, in solution.