拉恩氏菌LRP3诱导形成碱式磷酸锌沉淀及其在Zn污染土壤修复中的作用

Rahnella sp.LRP3 Induces Basic Zinc Phosphate Precipitation and Its Role in Zinc Contaminated Soil Remediation

采用批式和土壤培养实验考察拉恩氏菌LRP3对Zn的磷酸盐矿物诱导及其在Zn污染土壤修复中的作用,并进行X射线衍射、扫描电子显微镜、能谱及Fourier变换红外光谱分析.结果表明,菌株LRP3对Zn^(2+)的最大耐受质量浓度为120mg/L;对溶液中Zn^(2+)的去除率为菌体细胞(97.4%)>发酵液(88.2%)>无菌发酵液(81.6%);菌株LRP3的发酵液可通过生物矿化作用诱导形成结晶良好的立方体状Zn_2(OH)PO_3矿物晶体;菌株LRP3的发酵液加入土壤后可快速降低DTPA-Zn的质量比,培养5d后DTPA-Zn的质量比平均下降78.4%,培养6d后土壤中Zn的弱酸提取态和可氧化态的质量比分别下降72.5%和56.2%,可还原态和残渣态的质量比分别增加85.1%和14.8%.因此,菌株LRP3对Zn^(2+)具有较强的抗性和吸附能力,可通过降解植酸释放磷酸根,进一步诱导形成碱式磷酸锌矿物晶体,从而降低土壤中Zn的生物有效性,可用于Zn污染土壤的绿色可持续修复.

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 Zn^2+ 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 Zn 2(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 Zn^2+. 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.