Abstract: The induction of zinc (Ⅱ)phosphate precipitation by Rahnella sp.LRP3 and its role in Zn contaminated soil were investigated by batch and soil culture experiments. Xray diffraction, scanning electron microscope, energy spectrum and Fourier transform infrared spectroscopy were analyzed. The results show that the maximum tolerable mass  concentration of strain LRP3 to Zn^2+ is 120 mg/L. The removal rate of Zn²⁺ in solution by strain LRP3 is bacterial cell (974%)>the fermentation broth (882%)>bacteria free fermentation broth (816%). The fermentation broth of strain LRP3 can be induced to form cubic mineral crystal Zn₂(OH)PO₃ with good crystallization by biomineralization. The fermentation broth of
 strain LRP3 can rapidly reduce the mass ratio of DTPAZn after adding to soil. After 5 d of incubation, the mass ratio of DTPAZn decreases by 784% on average. After 6 d of incubation, the mass ratios of weak acid extractable state and oxidizable state of Zn in soil decrease by 72.5% and 56.2% , respectively, and the mass ratios of reductive state and residual state increase by 851% and 148%, respectively. Therefore, strain LRP3 has strong  resistance and adsorption capacity Zn²⁺. It can release phosphate by degrading phytic acid and further induce the Zn (Ⅱ)phosphate mineral crystal, which reduce the bioavailability of Zn in soil. So strain LRP3 can be applied in the green and sustainable remediation of Zn contaminated soil.

Key words: phosphate mineralization, zinc, Rahnella sp., heavy , metal pollution in soil, microbial remediation