SEM and AFM images of pyrite surfaces after bioleaching by the indigenous Thiobacillus thiooxidans

H. L. Liu*, B. Y. Chen, Y. W. Lan, Y. C. Cheng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


The bioleaching mechanism of pyrite by the indigenous Thiobacillus thiooxidans was examined with the aid of scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of the pyrite surface. The presence of pyrite eliminated the lag phase during growth of this microorganism. This was due to the stimulatory effect on cell growth of the slight amount of Cu 2+ that had leached from the pyrite. Zn2+ was found to be much more readily solubilized than Cu2+. The efficiency of bioleaching was four times higher than that of chemical leaching. SEM images provided evidence of direct cell attachment onto the pyrite surface, thereby enhancing the bioleaching rate. Furthermore, extracellular polymeric substances (EPSs) were found on the pyrite surface after 4 days of oxidation. AFM images showed that the pyrite surface area positively correlated with the oxidation rate. A combination of direct and indirect mechanism is probably responsible for the oxidation of pyrite by T. thiooxidans.

Original languageEnglish
Pages (from-to)414-420
Number of pages7
JournalApplied Microbiology and Biotechnology
Issue number4
Publication statusPublished - 2003 Sept
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology


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