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| Screening of Cd（Ⅱ）-resistant bacteria and its biomineralization of cadmium sulfide to remove cadmium ions in solution |
| Received:February 19, 2021 |
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| KeyWord:heavy metal;biomineralization;cadmium sulfide;Cd（Ⅱ）-resistant bacteria |
| Author Name | Affiliation | E-mail | | XU Shao-zu | College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China | | | ZHANG Mei-li | College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China | | | QIN Jun-mei | College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China | | | CAO Xiao-xia | College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China | | | LIU Fen-wu | College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China | lfwlfw2008@163.com |
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| Abstract: |
| Cadmium in heavy metal-polluted water has attracted widespread attention because of its high toxicity. Biomineralization is the transformation of toxic heavy metals into incompatible and less harmful compounds through microbial metabolism processes; it has become a research hotspot in the field of environmental pollution prevention and control. In this study, a cadmium-resistant bacterium, N1905, was isolated from heavy metal-contaminated soil and identified as Enterobacter ludwigii N1905 based on 16S rRNA sequence analysis. Results showed that strain N1905 was tolerant to many heavy metal types. The minimum inhibitory concentration（MIC）of Cd（Ⅱ）in an LB liquid medium was 8 μmol·L-1, and the normal growth of strain N1905 was significantly inhibited under high concentrations of Cd（Ⅱ）. Simultaneously, it was found that bacteria N1905 could produce hydrogen sulfide with L-cysteine as the specific substrate. In the coculture of strain N1905 with 1 μmol·L-1 cadmium nitrate and 2 μmol·L-1 L-cysteine, Cd（Ⅱ）ions in aqueous solution were approximately 100% removed by extracellular precipitation of cadmium sulfide. In addition, N1905 could efficiently remove cadmium ions from a variety of complex aqueous solutions. X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, and spectroscopic analysis showed that the biosynthesized CdS was composed of nanoparticles with optical properties. |
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