THERMOACIDOPHILIC ARCHAEA, OXIDIZING FERROUS IRON, ELEMENTAL SULFUR AND REDUCED SULFUR COMPOUNDS ISOLATED FROM DIFFERENT SULFIDE DEPOSITS IN BULGARIA
RALITSA ILIEVA*, MIHAIL ILIEV, VENETA GROUDEVA, BOYANKA ANGELOVA
Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
*Corresponding author: ralitza_ilieva@abv.bg
Keywords: Thermoacidophilic archaea, Sulfolobus, Bioleaching, Chemolithotrophs
Abstract: Acidophilic chemolithotrophs oxidizing sulfide minerals, ferrous iron, elemental sulfur and reduced sulfur compounds are the typical microbiota of the sulfide ore deposits. At the same time, the thermoacidophilic archaea can also be found in such habitats because of their specific growth requirements. These archaea belong mainly to genera Sulfolobus, Metallosphaera and Ferroplasma. They are an excellent candidate for different industrial metal extraction applications, based on their oxidative potential and metabolic activity.
In this study the diversity of thermoacidophilic archaea from some Bulgarian sulfide ore deposits was investigated. Elective media and specific conditions of cultivation were used to obtain enriched and pure cultures and their identification by the methods of classical taxonomy. The results showed that archaea from genera Sulfolobus, Metallosphaera and Ferroplasma are present in some of the sulfide deposits investigated. The isolates are the most closed to Sulfolobus metallicus, Metallosphaera cuprina and Ferroplasma acidiphilum. The isolates oxidizing ferrous iron, elemental sulfur and metal sulfides are suitable for industrial extraction of metals.