人苍白杆菌对2,3',4,4',5-五氯联苯的降解特性及其细胞响应机制研究

Degradation of 2,3′,4,4′,5-pentachlorodiphenyl by Ochrobactrum anthropi and cellular response mechanism analysis

从电子垃圾拆解场地污染土壤中分离筛选出一株多氯联苯降解菌人苍白杆菌,以2,3’,4,4’,5-五氯联苯(PCB 118)为目标污染物,通过菌株降解特性及代谢产物、转录组学分析,探究了PCB 118的最佳降解条件和好氧降解机制.结果表明,当PCB 118初始浓度小于0.1 mg·L^(-1)时,降解率可达80%以上.降解产物分析表明,人苍白杆菌可通过羟基化作用与脱氯作用降解PCB 118,且由于污染物的胁迫作用,会产生过量的活性氧,破坏菌体细胞质膜结构,同时激活其抗氧化机制.同时,转录组学分析发现,人苍白杆菌降解PCB 118的过程由多种代谢途径协同完成,菌体在PCB 118及其中间代谢产物的胁迫作用下,其碳水化合物代谢和膜运输功能受到的扰动程度最大.该研究表明采用人苍白杆菌作为新型功能菌种对多氯联苯污染土壤的原位生物修复具有重要意义.

A polychlorinated biphenyl degrading bacterium Ochrobactrum anthropi was isolated from contaminated soil of e-waste dismantling site.With 2,3′,4,4′,5-pentachlorinated biphenyl(PCB 118)as the target pollutant,the optimal degradation conditions and aerobic degradation mechanism of PCB 118 were explored through the degradation characteristics,metabolites and transcriptomics analysis of the strain.The results showed that when the initial concentration of PCB 118 was less than 0.1 mg·L^(-1),the degradation rate could reach more than 80%.Analysis of degradation products showed that PCB 118 could be degraded by Ochrobactrum anthropi through hydroxylation and dechlorination,and excessive reactive oxygen species would be produced due to the stress effect of pollutants,which destroyed the plasma membrane structure of the bacterial cells and activated its antioxidant mechanism.At the same time,transcriptomic analysis showed that the degradation process of PCB 118 by Ochrobactrum anthropi was coordinated by a variety of metabolic pathways.Under the stress of PCB 118 and its intermediate metabolites,the carbohydrate metabolism and membrane transport function of Ochrobactrum anthropi were most disturbed.This study indicated that the use of Ochrobactrum anthropi as a new functional strain is of great significance for in situ bioremediation of polychlorinated biphenyls contaminated soil.