Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
J Environ Sci (China). 2019 Feb;76:217-226. doi: 10.1016/j.jes.2018.04.029. Epub 2018 May 8.
Dibenzothiophene (DBT) degradation mechanisms and the transformation of pathways during the incubation of three types of coastal sediments with C/N ratios ranging from 1 to 9 were investigated. The DBT degradation efficiencies were clearly improved with increasing C/N ratio in reed wetland sediments, tidal wetlands sediments and estuary wetland sediments. The quantitative response relationships between DBT degradation rates and related functional genes demonstrate that the Kodama pathway-related gene groups were dominant factors at low C/N ratios, while the 4S-related gene groups mainly determined the degradation rate when the C/N ratio was up to 5. Network analysis also shows that the pathway shifts from the Kodama pathway to the 4S pathway occurred through changes in the connections between functional genomes and rates. Furthermore, there were competition and collaboration between the Kodama and 4S pathways. The 4S pathway-related bacteria were more active in estuary wetland sediments compared with reed wetland sediments and tidal wetland sediments. The higher degradation efficiency in estuary wetland sediments may indicate the greater participation of the 4S pathway in the DBT biodegradation reaction. And the effects of ring cleavage of Kodama pathway caused more complete metabolizing of DBT.
研究了 C/N 比为 1 至 9 的三种沿海沉积物在孵育过程中二苯并噻吩（DBT）的降解机制和途径转化。在芦苇湿地沉积物、潮汐湿地沉积物和河口湿地沉积物中，随着 C/N 比的增加，DBT 的降解效率明显提高。DBT 降解率与相关功能基因的定量响应关系表明，在低 C/N 比下，Kodama 途径相关基因群是主要因素，而当 C/N 比达到 5 时，4S 途径相关基因群主要决定了降解率。网络分析还表明，通过改变功能基因组和速率之间的连接，途径从 Kodama 途径向 4S 途径发生了转变。此外，Kodama 和 4S 途径之间存在竞争和合作。与芦苇湿地沉积物和潮汐湿地沉积物相比，河口湿地沉积物中与 4S 途径相关的细菌更为活跃。河口湿地沉积物中更高的降解效率可能表明 4S 途径在 DBT 生物降解反应中参与度更大。而 Kodama 途径的环裂解作用导致 DBT 更完全的代谢。
