Abstract: In this study,rock phosphate was used as the phosphorus source for testing the phosphate-solubilizing ability of Acinetobacter indicus JL-1. The single-factor experiments and response surface test were utilized to determine the optimal conditions for degrading rock phosphate,and the optimal phosphate solubilizing condition was as follows：17 g/L glucose as carbon source,1.2 g/L the compound nitrogen source of ammonium sulfate and yeast powder at a mass ratio of 1∶1,2.0 g/L rock phosphate powder,incubation temperature 28℃,pH 7.0,and inoculum size 1%. Under the optimal condition,the dynamic phosphate-solubilizing curve showed that the maximal solubilizing phosphate concentration was 4.65 μg/mL at 60 h,the phosphate-solubilizing rate was 2.34%,and the number of colonies reached the highest,which was 10.65 log（CFU/mL）,while the pH reached the lowest. The Shapei experiment demonstrated that 72.08% of the available phosphorus was directly released,7.63% was stored in the cells,and 20.29% was assimilated by the strain.

Key words: phosphate-solubilizing bacteria, Acinetobacter indicus JL-1, rock phosphate, characteristics of phosphate solubilization