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研究报告

The isolation of a urease-producing bacterium and its function of carbonate mineralization of Cd²⁺ ions

摘要：微生物诱导碳酸盐沉积（MICP）技术是目前镉污染治理的研究热点.本研究从土壤中分离出了一株高效产脲酶菌株，培养44 h后，该菌株对尿素的水解率达90.5%，培养液pH高达9.15.该菌株能诱导Cd²⁺形成碳酸盐，对0.1 g·L^-1的模拟镉污染污水中游离态Cd²⁺的固化去除率达70.5%.XRD和FTIR结果显示，固化产物为碳酸镉；SEM结果显示，固化产物粒径为10~100 μm，主要以椭圆形颗粒包裹在细菌表面.固化产物可耐受pH为3.5，预示该菌株在治理镉污染方面具有应用潜能.

Abstract：The microbial induced carbonate precipitation (MICP) of Cd²⁺ ions is becoming a hotspot. This paper isolated a bacterium strains which can effectively producing urease from soil, it hydrolyzed the 90.5% of urea in the liquid incubated medium after incubating 44 h, thereby increased the pH of the solution to 9.15. The urease-producing bacteria could induce the carbonate mineralization of Cd²⁺ ion, we found that when growing in 0.1 g·L^-1 of simulated wastewater that polluted by cadmium, the removal rate of free Cd²⁺ ion reached 70.5%. The results of XRD and FTIR showed that the production was cadmium carbonate. Based on the results of SEM, it was found that the particle size of oval-shaped mineralized product ranked 10~100 μm, they were alongside and surrounded on the surface of bacterial cells. The acid resistance value of the mineralization product reached 3.5, there will be widely application of the urease-producing bacteria among the governance area of cadmium pollution.