厌氧条件下 2,2',4,4'-四溴联苯醚的微生物降解

多溴联苯醚是环境中的新兴污染物,其中2,2’,4,4’-四溴联苯醚(BDE-47)在环境(尤其是水环境)中普遍存在且生物毒性很高.以BDE-47为对象,研究了6组含脱卤球菌的培养液对BDE-47的降解,目的是了解厌氧条件下BDE-47的微生物降解及其动力学.采用100 mL血清瓶作为厌氧反应器,对厌氧微生物进行培养.对每组菌作两种处理,一是仅加入BDE-47作为能源(设计终浓度为200μg.L-1),另一是同时加入BDE-47和三氯乙烯(TCE)作为能源(设计终浓度分别为200μg.L-1和13mg.L-1).经过3个月的实验,两组含脱卤球菌的培养液(6M6B和T2)均能明显降解BDE-47,生成BDE-17、BDE-4及少量的DE,TCE的存在一定程度上减弱了6M6B和T2菌对BDE-47的降解.采用PCR-DGGE法对不同培养菌液的群落结构进行比较,发现醋酸杆菌属与BDE-47的降解关联较大.在3种不同初始浓度(50、250和500μg.L-1)条件下,BDE-47的降解速率分别为0.003 3、0.001 4和0.001 0 d-1.本研究表明,厌氧条件下BDE-47在细菌的作用下可发生还原降解,生成BDE-17和BDE-4.醋酸杆菌属可能在BDE-47的降解中起较大作用.高浓度的BDE-47在一定程度上会抑制降解菌的活性.

Microbial Degradation of 2,2',4,4'-Tetrabrominated Diphenyl Ether Under Anaerobic Condition

Polybrominated diphenyl ethers are emerging contaminants in the environment, among which 2, 2' 4, 4'-tetrabrominated diphenyl ether (BDE-47) is one of the most frequently detected and the most toxic to organisms. Using BDE-47 as the object, this study investigated the degradation of BDE-47 by six enriched cultures containing Dehalococcoides species. The purpose is to understand the microbial degradation of BDE-47 under anaerobic condition and its kinetics. Serum bottles of 100 mL were used to construct the microcosms and enrich the anaerobic microorganisms. For each culture, two treatments were performed. One used BDE-47 as the only energy source with the designed concentration of 200 microg x L(-1), and the other used both BDE-47 and trichloroethene (TCE) as the energy source with the designed concentrations being 200 microg x L(-1) and 13 mg x L(-1), respectively. After three months of experiment, two enriched cultures (6M6B and T2) could obviously degrade BDE-47, producing BDE-17 and BDE-4 (and small amount of DE). The presence of TCE inhibited the degradation of BDE-47 by 6M6B and T2 cultures to a certain degree. The PCR-DGGE assay was performed to compare the microbial community structure of various enrichments and it was found that Acetobacterium sp. had good correlation with the degradation of BDE-47. Under three different initial BDE-47 concentrations (50 microg x L(-1), 250 microg x L(-1) and 500 microg x L(-1)), the degradation rates of BDE-47 were 0.003 3, 0.001 4 and 0.001 0 d(-1), respectively. This study demonstrated that BDE-47 could be reductively degraded by bacteria under anaerobic condition, producing BDE-17 and BDE-4. Acetobacterium sp. might play an important role in the degradation of BDE-47. High concentration of BDE-47 might inhibit the activity of the BDE-47 degrading bacteria to a certain degree.