Biooxidation of pyrite by defined mixed cultures of moderately thermophilic acidophiles in pH‐controlled bioreactors: Significance of microbial interactions

• DOI: 10.1002/bit.20138
• Publication Date: 2004-08-17T23:10:14Z
• Authors: Naoko Okibe; D. Barrie Johnson
• Keywords: Autotroph; Acidithiobacillus

Abstract The oxidative dissolution of pyrite (FeS 2 ) by pure and mixed cultures moderately thermophilic acidophiles was studied in shake flask pH‐controlled bioreactors, incubated at 45°C. Various combinations seven eubacteria (a Leptospirillum sp. (MT6), Acidimicrobium ferrooxidans , Acidithiobacillus caldus an Alicyclobacillus (Y004), three Sulfobacillus spp.) one archaeon ( Ferroplasma MT17) were examined. Pyrite determined measuring changes soluble iron generation acidity, microbial populations monitored using a combined culture‐dependent (plate counts) culture‐independent (fluorescent situ hybridization) approach. In cultures, the most efficient pyrite‐oxidizing acidophile MT6, which unique among prokaryotes used being obligately autotrophic. Mixed MT6 sulfur‐oxidizer At. generated more acidity than iron‐oxidizer, though this did not necessarily enhance dissolution. contrast, culture obligate heterotroph Y004 oxidized rapidly completely synchronized bioreactors. Although autotroph, “heterotrophically inclined” Am. both ineffective leaching culture, two bacteria able to accelerate mineral. Concentrations dissolved organic carbon accumulated >100 mg/L some effective bioleaching systems found be consortia containing autotrophic heterotrophic moderate thermophiles. A comprising autotrophs MT17, all those Mutualistic interactions between physiologically distinct acidophiles, involving transfer inorganic transformations sulfur, considered have critical roles optimizing © 2004 Wiley Periodicals, Inc.