三氯乙烯降解菌的分离鉴定及其降解特性

Isolation and identification of trichloroethylene-degrading bacteria and their degradation characteristics

三氯乙烯是一种具有"三致"效应的有机氯代烃化合物,作为一种重要的化工原料在工业上广泛应用,同时也造成了大量的三氯乙烯进入自然环境,引起了严重的环境污染。为获得更为丰富的三氯乙烯降解微生物资源,利用水-硅油双相系统从实验室高浓度三氯乙烯胁迫底泥中,分离筛选得到两株三氯乙烯降解菌WF1、FT10。在三氯乙烯初始质量浓度为5mg·L-1的条件下,培养72h,菌WF1、FT10对三氯乙烯的降解率分别为53.36%、48.06%;在500mg·L-1乙酸钠作为共代谢基质的情况下,降解率分别为55.95%、55.62%,降解速率明显提高。根据形态学观察、16项生理生化实验和16S rRNA序列分析结果,将菌株WT1归为Achromobacter xylosoxidans,将菌株FT10归为Sporosarcina aquimarina。对菌株培养条件进行优化,经SlideWrite统计软件拟合,菌株WT1和FT10在牛肉膏蛋白胨液体培养基上的最适生长温度分别为33.7℃和35.4℃,最适生长pH分别为7.6和7.9。

Trichloroethylene is one of chlorinated organic compounds widely used as a solvent and degreasing agent in industry. Because of uninformed disposal in the past, trichloroethylene has become one of major contaminant in environment, and this situation has brought about a serious public concern for its toxicity. A promising approach to solving this problem is bioremediation using degrading-bacteria. This study aims to isolate and characterize novel bacteria capable of degrade trichloroethylene, using an aqueous-silicon oil two-phase system. Two degrading-bacteria were isolated from trichloroethylene contaminated sediments sample by enriching with trichloroethylene as carbon source. At the end of the 72 h experiments, 53.36% of trichloroethylene had disappeared with strain WT1 when the initial concentration of trichloroethylene was 5 mg·L^-1, but 55.95% of trichloroethylene had disappeared with 500 mg·L^-1 acetate as the cometabolism substrate. And 48.06% of trichloroethylene had disappeared with strain FT10, but 55.62% of trichloroethylene had disappeared with the same cometabolism substrate. Biochemical, physiological characteristics and phylogenetic study based on 16S rRNA gene sequences all indicated that strain WF1 should be placed in the Achromobacter xylosoxidans, and that strain FT10 should be placed in the Sporosarcina aquimarina. Cultural conditions were optimized and the data were analysis by matched curves using the software of SlideWrite plus 7.0. The optimum temperature and optimum pH of strain WT1 were 33.7 ℃ and pH 7.6. And the optimum temperature and optimum pH of strain FT10 were 35.4 ℃and pH 7.9.