Abstract:Phosphorus is one of the essential nutrients for plants, but in most cultivated soil, phosphorus is easy to combine with Fe, Ca and Al to form invalid phosphorus, which is difficult for plants to directly absorb and utilize. Inoculating phosphate solubilizing bacteria (PSB) into compost can promote the conversion of insoluble phosphate to available phosphate, which is a good way to improve the utilization of phosphate. High efficient PSB were screened from chicken manure aerobic compost to provide strains for the preparation of bioaugmented phosphorus rich compost. NBRIY medium was used to screen PSB, and PVK medium was used to screen efficient PSB, which was identified by 16S rDNA Molecular biology. The effects of different carbon sources, nitrogen sources, initial pH, insoluble phosphorus species, insoluble phosphorus addition and soluble phosphorus concentration on the phosphate solubilizing ability of the bacteria were studied. Seven phosphate solubilizing bacteria named PSB1~PSB7 were obtained. After re-screening, PSB6 had the largest amount of dissolved phosphorus, which was 126.37 mg/L; the amount of dissolved phosphorus in other treatments ranged from 50.12 mg/L to 109.56 mg/L. PSB6 was identified as Bacillus sp. (MW513386). Under the optimum conditions of glucose as C source, ammonium sulfate as N source and initial pH of 7.0, the phosphate content of PSB6 was 126.37 mg/L. The most suitable insoluble phosphate for PSB6 is tricalcium phosphate; when tricalcium phosphate is 2.5 g/L, the maximum soluble phosphate content is 170.5 mg/L. When the concentration of initial soluble phosphate in the culture medium was 1 mmol/L, PSB6 with a higher amount of soluble phosphate (200.2 mg/L); when the concentration of initial soluble phosphate exceeded 10 mmol/L, the strain did not play the role of phosphate solubilization. PSB6 has good ability of dissolving phosphate of tricalcium phosphate, and can be used in the preparation of phosphate solubilizing bacterial fertilizer.