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| Isolation and Cadmium Adsorption Mechanisms of Cadmium-Resistant Bacteria Strains |
| Received:April 02, 2015 |
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| KeyWord:cadmium-resistant bacteria;selection;cadmium pollution;adsorption mechanism |
| Author Name | Affiliation | E-mail | | LIN Xiao-yan | Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, China National Rice Research Institute, Hangzhou 310006, China | | | MOU Ren-xiang | Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, China National Rice Research Institute, Hangzhou 310006, China | | | CAO Zhao-yun | Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, China National Rice Research Institute, Hangzhou 310006, China | | | ZHU Zhi-wei | Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, China National Rice Research Institute, Hangzhou 310006, China | | | CHEN Ming-xue | Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, China National Rice Research Institute, Hangzhou 310006, China | cmingxue@163.com |
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| Abstract: |
| 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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