MICROBIOLOGICAL FORMATION OF BASIC FERRIC SULFATES

Abstract

The iron-oxidizing bacterium Thiobacillus ferrooxidans was isolated from yellow-brown deposits found in soil, shale, metamorphic rock, and a uranium mine. In addition to the bacterium and pyrite, jarosite (K Fe 3 (SO 4 ) 2 (OH) 6 ), a basic ferric sulfate, was found to be present in the deposits. Oxidation of ferrous sulfate by the organism in liquid medium resulted in the formation of jarosite. On a solid medium of agar containing ferrous sulfate, ammoniojarosite (NH 4 Fe 3 (SO 4 ) 2 (OH) 6 ) was formed. Because jarosite can be synthesized at 25 C and 1 atm, it" is suggested that under natural conditions T. ferrooxidans plays a role in the formation of basic ferric sulfates.