Characterization of Some Agricultural Soils: Presence and Activity of Tilemsi Rock Phosphate-Solubilizing Thiobacilli

The bacteria Thiobacillus thioparus, Thiobacillus thiooxidans and Thiobacillus ferooxidans are known to be able to oxidize elemental sulfur in soils and influence phosphorus solubilization. These bacteria can solubilize the phosphorus of apatite rock by producing sulfuric acid from the oxidation of elemental sulfur and some sulphide. We think that the capacity of these bacteria can be exploited to set up a biophosphate from Tilemsi natural rock phosphate exploited in Mali. This work aims to identify, isolate and characterize Tilemsi rock phosphate (TRP) solubilizing Thiobacillus strains in various agricultural soils. Obtained results showed that the analyzed soils are poor in Thiobacillus and that the quantity of acid produced and TRP solubilized is directly proportional to the growth of these bacteria.