一株耐镉细菌的分离及其富集Cd的机理  

Isolation and bio-accumulation mechanisms of a Cd-resisting bacterium

作　　者：刘红娟[1] 张慧[1] 党志[1] 易筱筠[1] 杨琛[1] 

机构地区：[1]华南理工大学环境科学与工程学院,广州510006

出　　处：《环境工程学报》2009年第2期367-371,共5页Chinese Journal of Environmental Engineering

基　　金：广东省科技计划国际合作项目(20070409004);广东省自然科学基金重点项目(05103552);广州市污染防治新技术新工艺研究开发与推广应用项目(穗环[2006]143)

摘　　要：从重金属镉污染土壤中筛选到一株对镉具有较强抗性和富集能力的细菌RC。经形态学观察和生理生化鉴定以及16SrDNA序列分析,RC为蜡状芽孢杆菌(Bacillus cereus)。在不同镉浓度液体培养条件下研究了菌体的生长曲线,并探讨了RC菌株对Zn、Cu的抗性,结果显示RC对不同重金属的抗性机制存在一定的差异。利用扫描电镜、透射电镜观察了镉在RC胞内外的沉积作用及分布情况,结果表明,在镉浓度为150 mg/L时菌体细胞壁及其内部可见大量的高电子密度颗粒,同时在菌体表面也有沉淀物附着。因此,胞内外沉积作用可能是该菌对高浓度镉的抗性和富集作用的重要途径。通过红外光谱探讨了RC积累镉前后细胞壁表面化学基团的变化情况,结果发现RC的细胞壁上参与积累作用的化学官能团主要有—OH、—NH、—CO和—CO—NH—等。A bacterial strain, named as RC, ities was isolated from cadmium-contaminated soil. possessing stronger cadmium resistance and accumulation abilAccording to its morphological and biochemical characteristics and 16SrDNA sequences analysis, it was identified as Bacillus cereus. Growth curves of RC were analyzed under cuhure liquid of different cadmium concentrations. The resistance of RC to Zn and Cu was studied. The results show that its resistance mechanisms to different heavy metals are discrepant. The cadmium precipitation and dis- tribution inside and outside the cell were studied with scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. With the 150 mg/L cadmium concentration, there were much granular cadmium precipitate on and inside the cell wall, and also precipitate adhering to the surface of the mycelium. Hence, precipitation inside and outside the cell may be an important way of cadmium resistance and accumulation of the bacterium. The accumulation of Cd in the strain was observed by infrared spectroscopy, which indicates the possible functional groups participated during the accumulation of Cd are --OH,--NH,--CO 和--CO--NH--, etc.

关 键 词：蜡状芽孢杆菌 镉 分离 富集 

分 类 号：X703.1[环境科学与工程—环境工程]