title: The isolation and use of iron-oxidizing, moderately thermophilic acidophiles from the Collie coal mine for the generation of ferric iron leaching solution.
abstract: Moderately thermophilic, iron-oxidizing acidophiles were enriched from coal collected from an open-cut mine in Collie, Western Australia. Iron-oxidizers were enriched in fluidized-bed reactors (FBR) at 60 degrees C and 70 degrees C; and iron-oxidation rates were determined. Ferrous iron oxidation by the microbiota in the original coal material was inhibited above 63;C. In addition to four iron-oxidizers, closely related to Sulfobacillus spp that had been earlier isolated from the 60 degrees C FBR, one heterotroph closely related to Alicyclobacillus spp was isolated. The Alicyclobacillus sp. isolated from the Collie coal mine tolerated a lower pH than known Alicyclobacillus spp and therefore may represent a new species. The optimum temperature for growth of the iron-oxidizing strains was approximately 50 degrees C and their maximum temperatures were approximately 60 degrees C. The FBR was adjusted to operate at 50 degrees C and was inoculated with all of the isolated iron-oxidizing strains. At 60 degrees C, an iron-oxidation rate of 0.5 g Fe(2+) l(-1) x h(-1) was obtained. At 50 degrees C, the iron-oxidation rate was only 0.3 g Fe(2+) l(-1) x h(-1). These rates compare favourably with the iron-oxidation rate of Acidianus brierleyi in shake-flasks, but are considerably lower than mesophilic iron-oxidation rates.
authors.affiliation: Institute of Environmental Engineering and Biotechnology, Tampere University of Technology, PO Box 541, 33101 Tampere, Finland. paivi.kinnunen@tut.fi
authors.forename: P H-M
authors.initials: PH
authors.lastname: Kinnunen
authors.forename: W J
authors.initials: WJ
authors.lastname: Robertson
authors.forename: J J
authors.initials: JJ
authors.lastname: Plumb
authors.forename: J A E
authors.initials: JA
authors.lastname: Gibson
authors.forename: P D
authors.initials: PD
authors.lastname: Nichols
authors.forename: P D
authors.initials: PD
authors.lastname: Franzmann
authors.forename: J A
authors.initials: JA
authors.lastname: Puhakka
mesh_terms: D001315:Australia; D001406:Bacillaceae / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D019149:Bioreactors; D003031:Coal / Q000382:microbiology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods*; D007501:Iron / Q000378:metabolism*; D008906:Mining; D010084:Oxidation-Reduction; D012996:Solutions; D013045:Species Specificity; D013455:Sulfur / Q000378:metabolism
chemical_list: D003031:Coal; D012996:Solutions; D013455:Sulfur; D007501:Iron