R ＆ D of treatment of soil contaminated with chlorinated organic compounds by combined method of chemical dehalogenation and microbial degradation

高氯代化合物一般不易被微生物降解，容易在土壤和地下水等环境中积累。在这项研究中，我们试图开发一种化学脱氯和微生物降解高氯化学品，如多氯联苯（PCB）和四氯乙烯（PCE），化合物被称为严重的环境污染物在世界各地的组合方法。对于PCB，碱催化分解法被用作化学处理。该方法对KC 300和KC 400的脱氯率高达99.79-99.98%，并在某油田中积累了大量的联苯，同时检测到少量的轻度氯化PCB（1-3氯）。这些多氯联苯进行微生物降解，得到少量的氯代苯甲酸作为最终产品。对于PCE，我们已经分离出一株属于Deuslfitobacterium属的厌氧细菌菌株Y51。菌株Y51以PCE为最终电子受体，通过三氯乙烯进行“脱卤呼吸”，将PCE脱卤为顺式1，2-三氯乙烯。Y51（600 nm处OD值为1.0）的休眠细胞在10 h内对低至0.01 mg/L和高至160 mg/L的PCE进行脱氯。然后将菌株Y51引入同一土壤中，导致更有效的脱卤。检测到乙烯和乙烷为最终脱氯产物。

Highly chlorinated compounds are generally recalcitrant for the microbialdegradation, and tend to accumulate in the environment such as soil and groundwater. In this study, we attempted to develop a combined method of chemical dechlorination and following microbial degradation of highly chlorinated chemicals such as polychlorinated biphenyls (PCB) and tetrachloroethylene (PCE), compounds known as serious environmental pollutants over the world. For PCB, the base catalyzed decomposition method was employed as a chemical treatment. By this method as high as 99.79-99.98% dechlorination was achieved from KC300 and KC400, and large amounts of biphenyl accumulated in an oil reservor, in which a small amount of lightly chlorinated PCB (1-3 chlorines) were detected. These PCBs were subjected to the microbial degradation to get a small amount of chlorinated benzoic acids as the final products. For PCE, we have isolated an anaerobic bacterium strain Y51 belonging to genus Deuslfitobacterium. Strain Y51 dehalogenated PCE to cis-1,2-dichrloroethene via trichloroethene by the process of "dehalorespiration" using PCE as a final electron acceptor. The resting cells of Y51 (OD 1.0 at 600 nm) dechlorinated PCE at the concentrations of as low as 0.01 and as high as 160 mg/L within 10 hr. The addition of elemetal iron toward the soil contaminated with PCE led to the dehalogenation of PCE. Then strain Y51 was introduced into the same soil, resulting in the more efficient dehalogenation. Ethylene and ethane were detected as the final dechlorination products.