Bioleaching Characteristics of Heavy Metals from Polluted Soil with Indigenous Aspergillus niger F2
Bioleaching Characteristics of Heavy Metals from Polluted Soil with Indigenous Aspergillus niger F2
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本土黑曲霉F2对污染土壤重金属的生物淋滤特性
DOI：
10.1166/jbmb.2019.1864
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发表时间：
2019-06-01
影响因子：
0.5
通讯作者：
Shi, Yan
中科院分区：
文献类型：
--
作者：
Deng, Xinhui;Chen, Runhua;Shi, Yan
土壤中的重金属可以被微生物提取出来。利用尼日尔F2菌株对污染土壤中的重金属进行生物淋滤，并研究其淋滤机理及对重金属的抗性。蔗糖对重金属的浸出率大于葡萄糖;同样，一步法的浸出率大于两步法。利用蔗糖和葡萄糖时有机酸的种类、含量和产量不同。一步法和碳源蔗糖比两步法和葡萄糖更适合菌株F2。通过透射电子显微镜、傅立叶变换红外分析和扫描电子显微镜结合能量色散X射线能谱分析，发现重金属被吸附在细胞壁上，并在生物浸出后沉淀在细胞中。换句话说，胞外滞留和胞内沉淀是菌株F2的重金属抗性的机制。此外，通过X射线衍射分析发现，生物淋滤后重金属的形态发生了变化。可溶性蛋白质含量随着重金属浓度的增加而降低，丙二醛含量随着重金属浓度的增加而增加。结果表明，F2菌株具有很好的重金属污染土壤的淋洗能力。
Heavy metals can be extracted from soil by microbes. The present study aimed to accomplish bioleaching of heavy metals from the polluted soil with indigenous Aspergillus niger F2 and to study the mechanism underlying bioleaching and resistance to heavy metals. The bioleaching ratio of heavy metals was greater for sucrose than for glucose; similarly, the ratio of the one-step method was greater than that of the two-step method. The types and content of organic acids and their production upon using sucrose differed from that upon using glucose. The one-step method and the carbon source, sucrose, are more suitable than the two-step method and glucose for strain F2. The heavy metals were adsorbed on the cell wall and precipitated in the cells after bioleaching, as revealed through transmission electron microscopy, Fourier-transform infrared analysis, and scanning electron microscopy with energy-dispersive X-ray spectroscopy analyses. In other words, extracellular retention and intracellular precipitation are mechanisms underlying heavy metal resistance in strain F2. Furthermore, the forms of heavy metals were altered after bioleaching, as revealed through X-ray diffraction analysis. Soluble protein content was decreased under higher heavy metal stress, and malonaldehyde content was increased with increased heavy metal content. The present results indicate that strain F2 has high potential for leaching heavy metals from polluted soil.