National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agroenvironmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China.
State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
Biodegradation. 2024 Jun;35(3):329-340. doi: 10.1007/s10532-023-10057-y. Epub 2023 Oct 17.
Heavy metals can severely influence the mineralisation of organic pollutants in a compound-polluted environment. However, to date, no study has focused on the effects of heavy metals on the active organic pollutant-degrading microbial communities to understand the bioremediation mechanism. In this study, toluene was used as the model organic pollutant to explore the effects of soils with different levels of heavy metal pollution on organic contaminant degradation in the same area via stable isotope probing (SIP) and 16 S rRNA high-throughput sequencing. Heavy metals can seriously affect toluene biodegradation and regulate the abundance and diversity of microbial communities. SIP revealed a drastic difference in the community structure of active toluene degraders between the unpolluted and heavy metal-polluted soils. All SIP-identified degraders were assigned to nine bacterial classes, among which Alphaproteobacteria, Gammaproteobacteria, and Bacilli were shared by both treatments. Among all active degraders, Nitrospira, Nocardioides, Conexibacteraceae, and Singulisphaera were linked to toluene biodegradation for the first time. Notably, the type of active degrader and microbial diversity were strongly related to biodegradation efficiency, indicating their key role in toluene biodegradation. Overall, heavy metals can affect the microbial diversity and alter the functional microbial communities in soil, thereby influencing the removal efficiency of organic contaminants. Our findings provide novel insights into the biodegradation mechanism of organic pollutants in heavy metal-polluted soils and highlight the biodiversity of microbes involved in toluene biodegradation in compound-polluted environments.
重金属会严重影响复合污染环境中有机污染物的矿化作用。然而，迄今为止，尚无研究关注重金属对活性有机污染物降解微生物群落的影响，以了解生物修复机制。在本研究中，以甲苯作为模式有机污染物，通过稳定同位素探测（SIP）和 16S rRNA 高通量测序，探讨了不同重金属污染水平的土壤对同一区域有机污染物降解的影响。重金属会严重影响甲苯的生物降解，并调节微生物群落的丰度和多样性。SIP 揭示了未污染和重金属污染土壤中活性甲苯降解菌群落结构的显著差异。所有 SIP 鉴定出的降解菌均被归为九个细菌纲，其中α变形菌纲、γ变形菌纲和芽孢杆菌纲在两种处理中均有存在。在所有活性降解菌中，首次发现硝化螺旋菌、诺卡氏菌、 Conexibacteraceae 和 Singulisphaera 与甲苯的生物降解有关。值得注意的是，活性降解菌的类型和微生物多样性与生物降解效率密切相关，表明它们在甲苯生物降解中起着关键作用。总体而言，重金属会影响土壤中的微生物多样性，并改变土壤中功能微生物群落，从而影响有机污染物的去除效率。本研究结果为重金属污染土壤中有机污染物的生物降解机制提供了新的见解，并强调了复合污染环境中参与甲苯生物降解的微生物的生物多样性。
