3种耐锑土壤细菌的筛选及对锑的吸附研究

从湖南省冷水江锡矿山尾渣土壤中筛选分离出3株具有较高锑耐性的细菌，通过宏观吸附结合X射线光电子能谱（XPS），阐明3株细菌对Sb（Ⅲ）和Sb（Ⅴ）的吸附机制.根据生理生化指标和16S rDNA序列同源性对比，鉴定出1株革兰氏阴性菌和2株革兰氏阳性菌，分别为人苍白杆菌（Ochrobactrum anthropi）、芽孢杆菌（Bacillus sp.）及蜡状芽孢杆菌（Bacillus cereus）.3株细菌都呈杆状，且都能在高锑含量营养液中良好生长.3株细菌对锑的等温吸附符合Langmuir模型，对锑的最大吸附量约为11.0~14.3 mg·g^-1，其中，蜡状芽孢杆菌对锑的吸附能力高于其它两株细菌，3株细菌对Sb（Ⅲ）的吸附量略高于Sb（Ⅴ）.XPS结果表明，细菌表面的羧基和氨基在锑吸附过程中发挥主导作用.本研究结果对于理解土壤微生物吸附固定锑机制及其在土壤修复中的应用有重要意义.

Screening of three antimony-resistant soil bacteria and their adsorption property for antimony

In this study, three high Sb-tolerance bacteria were screened from the tailing soils in LengshuiJiang City, Hunan Province. Batch adsorption experiments and X-ray photoelectron spectroscopy (XPS) analyses were carried out to investigate the binding mechanisms of Sb(III)/Sb(V) to bacterial cell surfaces. Based on physiological and biochemical property analyses and 16S rDNA sequence homology comparison, a Gram-negative bacterium and two Gram-positive bacteria were identified, namely Ochrobactrum anthropi, Bacillus sp. and Bacillus cereus, respectively; All three bacteria are rod-shaped and can grow stably in nutrient solution containing high concentration of Sb. The isotherm adsorption of Sb(III)/Sb(V) by the three bacteria conforms to the Langmuir model, and the maximum adsorption capacities for Sb(III)/Sb(V) are between ~11.0 mg·g^-1 to 14.3 mg·g^-1. Specifically, the adsorption capacity of Bacillus cereus is larger than that of the other two bacterial strains. Moreover, Sb(III) adsorption is slightly larger than Sb(V) for the three bacteria; XPS analyses reveal that the surface carboxyl and amino functional groups play a dominant role in the binding of Sb(III)/Sb(V). The results of this study have important implications for understanding the adsorption mechanisms of Sb by soil microbes and their applications in soil remediation.