关键词: 二苯并噻吩, 湿地沉积物, 环渤海, 功能基因, 降解途径

Abstract:

In order to reveal the dibenzothiophene (DBT) degradation pathway in Bohai Rim typical wetland sediments at different temperatures, three different types of wetland sediments were chosen: reed wetland sediments (RWS) collected from Liao River estuary, tidal wetlands sediments (TWS) collected from Beida harbor and estuary wetland sediments (EWS) collected from Yellow River estuary. These samples were cultured for 56 days under the condition of simulating the seasonal temperature. The degradation rates were determined and the abundance of DBT degradation functional genes were analyzed. The DBT degradation pathways in different wetland sediments and at different temperatures were analyzed using a quantitative response model established between DBT degradation rate and degradation functional gene groups. Results show that the degradation rate and the abundance of degradation functional genes are basically improved with the increase of temperature. At 4ºC, the trend of DBT degradation rate is EWS>TWS>RWS; while at 30ºC, it is TWS>EWS>RWS. Functional genes catA and dszB affect DBT degradation rate. Kodama pathway functional genes nagAc/nahAc and nidA are the main functional genes for DBT degradation in all the three typies of wetland sediments at low temperature while nidA is the the main at medium temperature. The 4S pathway gene dszB plays an important role for DBT degradation.

Key words: dibenzothiophene, wetland sediments, Bohai Rim, functional genes, degradation pathway