Thermophilic Microbial Species

Diversity, distribution and systematics
Temperature is one of the most important ecological factors that affect microbial activities and their distribution (Johri et al., 1999; Maheshwari et al., 2000). Microbial species exist in a great variety of environments with extremes of temperature, pH, chemical composition and pressure. This is due to their genetic and/or physiological adaptations (Cooney and Emerson, 1964; Johri et al., 1999; Maheshwari et al., 2000). Of the three domains of life, most of the thermophilic microbial species which have been described belong to Archaea and Eubacteria (Barns et al., 1996). The maximum temperature limit for Eukaryota has been recorded as 62ºC (Tansey and Brock, 1972). There are fewer than 50 species of

Soils in tropical countries do not appear to have a higher population of thermophilic fungi than soils in temperate countries as believed earlier. Their widespread occurrence could well be due to the dissemination of propagules from self-heating masses of organic materials (Maheshwari et al., 1987). Tansey and Brock (1972) reported that the thermophilic fungi are more common in acidic thermal habitats than in neutral to alkaline environments. These fungi constitute a heterogeneous physiological group of various genera in the Zygomycetes, Ascomycetes, Deuteromycetes (anamorphic fungi), and mycelia sterilia (Johri et al.,

A subsequent document of thermophilic fungi was published by Mouchacca (1997) in which he attempted a critical reappraisal of the nomenclatural, and in some cases, also of the taxonomic status of the known thermophiles. Latest valid names for all thermophilic fungal taxa have been elaborated by Mouchacca (2000). The original names of some of the taxa have been retained based on their taxonomic