451-464Living organisms synthesize a wide array of
enzymes, which catalyze a myriad of reactions both inside and outside the cell.
The acidothermophilic iron-oxidizing bacteria represent a group of obligately
autotrophic chemolithotrophs, They include mesophilic Thiobacillus
thiooxidans, Leptospirillum ferrooxidans and thermophilic bacteria such as Sulfolobus
and Acidianus species. Several studies have shown the importance and
feasibility of microbiological prospecting for sulphide ore deposits.
Acidothermophilic autotrophic bacteria are now considered as an ideal source to
exploit more unusual commercial applications of Geo-biotechnology, especially
for metal and mining industry. The mining of copper, uranium, molybdenum, zinc,
silver, gold, etc, from their sulphide ores is successfully possible with these
microbes. The predominant characteristic of chemolithotrophs is their ability
to survive and flourish in a completely inorganic aqueous environment with a
supply of oxidizable substrate and CO2, A number of different species have now
been isolated from high temperature regions and their potential for the rapid leaching
of some ores. The ability of such isolates to tolerate high concentration of
toxic heavy metals makes them excellent tools for accumulation and/or for
biochemical transformation of metals. The outline of such applications are
described in the present review