Biosolubilization of phosphorus from rock phosphate by moderately thermophilic and mesophilic bacteria

Biosolubilization of phosphorus from rock phosphate (RP) by a moderately thermophilic bacterium, Acidithiobacillus caldus and a mesophilic bacterium, Acidithiobacillus thiooxidans were carried out in shake flasks containing elemental sulfur (S0) as an energy substrate. The phosphate solubilizing ability of A. caldus was more effective than A. thiooxidans when carried out under pH 2.5, 160 rpm, 45 °C and 30 °C for the moderate thermophile and the mesophile, respectively. Moreover, the phosphorus solubilizing rate from RP by A. caldus was influenced markedly by initial pH, temperature, RP concentration and dosage of S0 addition.