Liu Hongwei, Yuan Ruiling, Sarkodie Emmanuel Konadu, Tang Jiahui, Jiang Luhua, Miao Bo, Liu Xueduan, Zhang Siyuan
School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
Key Laboratory of Biometallurgy of Ministry of Education, Changsha, China.
Front Microbiol. 2022 Aug 10;13:977171. doi: 10.3389/fmicb.2022.977171. eCollection 2022.
Soil contamination with potentially toxic element such as chromium (Cr) poses a threat to the environment and human health. The environmental toxicity of Cr is related not only to the total Cr content but also to the distribution of Cr fractions. In this study, laboratory simulation experiments were conducted to explore the characteristics of Cr fractions and responses of the functional microbial community during dynamic leaching and static drying processes. The results showed that acid-soluble Cr and reducible Cr transformed into other relatively stable fractions under dry conditions, and ammonium nitrogen promoted the transformation. Nitrate-nitrogen was significantly positively correlated with Cr fractions in the wet stage ( < 0.05), while ammonium nitrogen showed the same relation in the dry process. Analysis of the microbial community showed that the bacterial and fungal genera Flavihumibacter, Altererythrobacter, Methylobacillus, Flavisolibacter, Lysobacter, and Cladosporium were related to the Cr fractions (acid-soluble Cr, reducible Cr, and oxidizable Cr) under wet conditions, while the microbial genera Ellin6067, MND1, and Ramlibacter were related to Cr fractions under dry conditions. Moreover, the proliferation of the functional microbial genera Methylobacillus, Ellin6067, and MND1 related to Cr fractions in the wet-dry conversion process alleviated the environmental toxicity of Cr. These findings provide useful information for the remediation of Cr-contaminated soils by monitoring the distribution fractions of Cr and the functional microbial community under wet-dry conditions.
土壤受到铬（Cr）等潜在有毒元素的污染会对环境和人类健康构成威胁。铬的环境毒性不仅与总铬含量有关，还与铬的形态分布有关。本研究通过实验室模拟实验，探讨了动态淋溶和静态干燥过程中铬形态特征及功能微生物群落的响应。结果表明，酸溶性铬和可还原铬在干燥条件下转化为其他相对稳定的形态，铵态氮促进了这种转化。硝态氮在湿润阶段与铬形态显著正相关（<0.05），而铵态氮在干燥过程中呈现相同关系。微生物群落分析表明，在湿润条件下，黄褐土杆菌属、交替赤杆菌属、甲基芽孢杆菌属、黄杆菌属、溶杆菌属和枝孢属细菌和真菌与铬形态（酸溶性铬、可还原铬和可氧化铬）有关，而在干燥条件下，Ellin6067、MND1和Ramlibacter属微生物与铬形态有关。此外，在干湿转化过程中，与铬形态相关的功能微生物属甲基芽孢杆菌属、Ellin6067和MND1的增殖减轻了铬的环境毒性。这些发现通过监测干湿条件下铬的分布形态和功能微生物群落，为铬污染土壤的修复提供了有用信息。
