| 林晓燕,牟仁祥,曹赵云,朱智伟,陈铭学.耐镉细菌菌株的分离及其吸附镉机理研究[J].农业环境科学学报,2015,34(9):1700-1706. |
| 耐镉细菌菌株的分离及其吸附镉机理研究 |
| Isolation and Cadmium Adsorption Mechanisms of Cadmium-Resistant Bacteria Strains |
| 投稿时间：2015-04-02 |
| DOI：10.11654/jaes.2015.09.011 |
| 中文关键词: 耐镉细菌 筛选 镉污染 吸附机理 |
| 英文关键词: cadmium-resistant bacteria selection cadmium pollution adsorption mechanism |
| 基金项目:国家自然科学基金青年基金项目(31100405);浙江省科技计划项目(2013C37037) |
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| 中文摘要: |
| 从重金属镉污染稻田土壤中筛选到两株对镉具有较强耐性的细菌菌株LCd1和LCd2。通过形态学观察、常规生理生化鉴定以及16S rDNA同源性分析,菌株LCd1和LCd2分别被鉴定为铜绿假单胞菌(Pseudomonas aeruginosa)和阴沟肠杆菌(Enterobacter cloacae)。这两株菌株分别在LB固体培养基上耐受400 mg·L-1和300 mg·L-1 的Cd2+,在LB液体培养基中耐受80 mg·L-1和50 mg·L-1的Cd2+。设计实验研究了两株菌株对7种重金属离子的吸附情况,结果显示两株菌都对铅和镉有较高的吸附率,对重金属Cr、Cu、Mn、Ni和Zn的吸附情况则不同,表明两株菌对不同重金属的耐性机制可能存在差异。利用扫描电镜观察发现,与未处理的菌株相比,镉处理菌体表面粗糙,出现不规则凸起,有大量沉淀物聚集,说明胞外沉淀可能是菌株吸附重金属的一个重要途径。进一步通过红外光谱研究了两菌株积累镉及多种重金属离子前后细胞壁表面化学基团的变化情况,结果发现两株菌可能由于本身性质不同,其细胞壁上参与镉及多种重金属吸附的基团不尽相同。 |
| 英文摘要: |
| Bacterial bioremediation of heavy metals has drawn increasing interests. However, the key to the bioremediation is bacterial strains with high metal resistance and absorption. Here we isolated two cadmium(Cd)-resistant bacterial strains LCd1 and LCd2 from rice paddy soil polluted by Cd. Based on morphological observation, conventional physiological and biochemical identification and 16S rDNA homology analysis, these two strains were identified as Pseudomonas aeruginosa and Enterobacter cloacae. They tolerated Cd2+ up to 400 mg·L-1 and 300 mg·L-1 in LB solid medium and 80 mg·L-1 and 50 mg·L-1 in LB liquid medium, respectively. We further examined their adsorption ability of 7 kinds of heavy metal ions. These two strains had higher adsorption of Pb and Cd than that of Cr, Cu, Mn, Ni, and Zn. Scanning electron microscopy(SEM) indicated that more rough surface, irregular convex, and obvious Cd precipitates appeared on the Cd2+-treated strains, compared to the untreated bacteria, implying that extracellular precipitation might be a way for strains to adsorb Cd. The infrared spectra showed that the chemical groups on cell walls of two strains were different after adsorption of Cd/multiple heavy metals. |
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