Distribution of oxidizing bacterial activities and characterization of bioleaching-related microorganisms in a uranium mineral heap.

The occurrence and activity of bioleaching-related microorganisms are highest at 0.25 m under the surface of a uranium mineral heap, and decrease at points deeper than 1 m inside the heap. Thiobacillus ferrooxidans, Th. acidophilus, Th. thiooxidans and Leptospirillum ferrooxidans have been found and isolated from different sites inside the heap. Other mesophilic iron- or sulphur-oxidizing bacteria and some moderate thermophile have also been isolated from deep (1 m and 4 m) sites and characterized. Several fungi and some yeasts are present in this bioleaching habitat.