Extremophile: Occurrence, Ecological Diversity and Taxonomic Aspects

The vast majority of our planet’s history of evolution has been dominated by prokaryotic life and has evolved to thrive in nearly all environmental conditions. In the last few years, unique organisms that live in severe and harsh conditions have captured scientists’ attention. These organisms known as extremophiles are further divided into acidophiles, alkaliphiles, halophiles, thermophiles, xerophiles, piezophiles and psychrophiles based on different extreme conditions. The extremophiles include all three domains of life such as archaea, bacteria and eukarya. These organisms produce special biocatalysts that function in harsh conditions and have novel applications in the food, chemical and pharmaceutical industries. Thermophiles produce certain enzymes that are used in natural detergents, in the removal of heavy metals and also in the treatment of certain cancers. Only a small portion of the microbes on Earth are currently used for mankind. New expansion in the production and cultivation of extremophiles as well as in the expression of the genes and cloning in the heterologous microorganisms expands the range of enzyme-driven conversions in the applications of industries. This chapter discusses various extremophiles and their occurrence, diversity and taxonomical characteristics.