Objective: In order to study the microbial diversity and the characteristics of cultivable microorganisms in bioleaching reactors.
Methods: Both conventional culture technique and analysis of a 16S rRNA sequence library were used. The pure cultures were isolated by enriching the samples under different cultural conditions. The morphology characters, physiology and biochemistry characters, genetic characters and oxidation efficiency to different minerals of cultured isolates were analyzed.
Results: The microbial community in bioleaching reactors identified through the gene clone libraries were closely related to bacteria including Leptospirillum sp., Sulfobacillus sp., Acidithiobacillus sp., Spingomonas sp. and Archaea including Sulfolobus sp., Ferroplasma sp. Five strains were isolated after enriching and culturing, which were corresponding to Acidithiooxidians caldus, Acidithiooxidians thiooxidans, Acidithiooxidans ferrooxidans, Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans. These isolates could oxidize sulfur or Fe2+ and different sulfide ores.
Conclusion: The bioleaching reactors were dominated by a small number of microbial species that were commonly found at thermoacidophilic environments.