Abstract

Phosphate-solubilizing bacteria (PSB) can effectively promote the recovery of phosphate-contaminated soil to environmentally safe phosphate levels. The ability and mechanisms of rock phosphate (RP) solubilization were studied using strain LX2 isolated from a phosphate mining wasteland, which was identified as Serratia sp. It was found that strain LX2 could grow at phosphate concentrations of 0–350 mg/L. Optimization of carbon and nitrogen sources was also conducted to increase RP solubilization. and maximum soluble phosphate concentration of 288.69 mg/L with glucose 20 g/L and NH₄Cl 0.5 g/L were obtained. The RP solubilization effect under different soluble phosphate concentrations showed that the effective RP solubilization ability by strain LX2 was always accompanied by a decrease in pH. Further, the mechanisms of RP solubilization were studied through Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The presence of strain LX2 caused more corrosive pores on RP surface, which represented the excellent insoluble phosphate solubilization ability. As the soluble phosphate content increased, a gypsum film covered the RP surface, which might prevent further RP solubilization. These results suggested that strain LX2 had great potential in solubilizing RP and could be used as a bioremediation approach of excessive phosphate in phosphate mining wasteland.

摘要

溶磷菌（PSB）可以有效促进受磷酸盐污染的土壤恢复到环境安全的磷酸盐水平。使用从磷酸盐采矿荒地分离的菌株 LX2 研究了磷矿 (RP) 溶解的能力和机制，该菌株被鉴定为沙雷氏菌。发现菌株 LX2 可以在 0–350 mg/L 的磷酸盐浓度下生长。还进行了碳源和氮源的优化以增加 RP 增溶。最大可溶性磷酸盐浓度为 288.69 mg/L，葡萄糖 20 g/L 和 NH ₄获得0.5g/L的Cl。不同可溶性磷酸盐浓度下的RP增溶效果表明，LX2菌株的有效RP增溶能力总是伴随着pH的降低。此外，通过傅里叶变换红外光谱 (FTIR) 和扫描电子显微镜 (SEM) 研究了 RP 增溶的机制。LX2 菌株的存在导致 RP 表面有更多的腐蚀孔，这代表了优异的不溶性磷酸盐增溶能力。随着可溶性磷酸盐含量的增加，石膏膜覆盖在 RP 表面，这可能会阻止 RP 进一步溶解。这些结果表明菌株LX2在溶解RP方面具有很大的潜力，可以作为磷矿荒地过量磷酸盐的生物修复方法。