| A strain C1 was isolated and purified from acid mine drainage of Tong Shan Kou mine at Tong Lu Shan in Hubei province and its growth characteristics, phosphate ore leached conditions and leaching mechanism was studied. The strain C1 was isolated from 9K medium and identified as Acidithiobacillus ferrooxidans by 16S rDNA analysis and it was named after C1. C1's optimum growth conditions were temperature 30℃, initial pH 2.0, inoculation amount 10% and rotation speed 150 r/min. The phosphate ore leached rate was 77.19% after 28 d when the temperature 30℃, initial pH 1.5, rotation speed 135 r/min, inoculation amount 2%, particle size of phosphate ore 74-97μm, FeSO4·7H2O 44.7 g/L, pyrite 15 g/L and phosphorous ore 10 g/L. Initial pH, inoculation amount, rotation speed and particle size of phosphate ore were selected for orthogonal experiment and the significant order of influence factors was pH>inoculation amount>rotate speed>paticale size of phosphate ore. Tween 20, 40, 60, 80 could improve the leached rate of the ore and the optimal dosage was 10 g/m3, 10 g/m3, 10 g/m3, 50 g/m3 respectively and the phosphate ore leached rate increase about 31.00%, 36.48%, 45.19% and 41.91% under these conditions. The phosphorus ore leached rate could reach 57.07%, 58.13%, 76.75% respectively after 4 d by ordinary leaching method among 9K, Waksman and 9K+S medium. However the phosphorus ore leached rate only reach 48.41% 25.16%, 58.89% after 22 d by batch leaching method in these three kinds of medium. When using pyrite as an energy source the phosphorus ore leached rate was 20.07% after 14 d by the bacteria which was mutated by UV for 3 min and was 31.69% higher than that of the control, the phosphorus ore leached rate was 21.96% after 14 d by the bacteria which was mutated by microwave for 10 s and was 51.87% higher than that of the control, the phosphorus ore leached rate was 20.98% after 14 d by the bacteria which was mutated by 0.02 mol/L nitrous acid and was 35.01% higher than that of the control, the phosphorus ore leached rate was 20.65% after 14 d by the bacteria which was mutated by 0.6% diethyl sulfate (DES) for 15 min and was 31.03% higher than that of the control, the phosphorus ore leached rate was 21.45% after 14 d by the bacteria which was mutated by 1.0% hydroxylamine and was 33.31% higher than that of the control, the rate of phosphorus ore leached was 24.86% after 14 d by the bacteria which was multiple mutated by microwave and different concentrations of nitrous acid and was 28.14% higher than that of the control, DES-mutated bacteria were then muti-mutated with different concentrations of hydroxylamine, but the phosphorus ore leached rate of multiple mutated C1 was lower than the control.Strain C1 reached adsorption equilibrium on the mineral surface after 40 min and the maximum adsorbing capacity was 41.48%. The phosphorus ore leached rate by strain C1 is 25.71% which was higher than 9.89% by chemical leaching method after 21 d. A certain amount of glycin, lysine and glutamic acid rather than leucine in the medium could improve phosphorus ore leached rate. The optimal dosage of glycin, lysine and glutamic acid was 0.5 g/L, 0.5 g/L and 1 g/L respectively and the phosphorus ore leached rate was about 24.07%,12.03%,7.6% higher than the control, but the effect of lysine and glutamic acid were not obvious.A certain amount of glucose rather than arabinose in the medium could improve phosphorus ore leached rate. The optimal dosage of glucose was 0.5 g/L and the phosphorus ore leached rate was about 15.54% higher than the control.
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