Background Chlorophenoxy compounds represent a group of selective herbicides widely used around the world.Chlorophenoxy herbicides are toxic,chemically stable,and can migrate into groundwater through soil leaching,pos...Background Chlorophenoxy compounds represent a group of selective herbicides widely used around the world.Chlorophenoxy herbicides are toxic,chemically stable,and can migrate into groundwater through soil leaching,posing a significant threat to drinking water safety and human health.Chlorophenoxy herbicides in groundwater aquifers are subject to anaerobic processes;however,the pathway and microbiology involved in the attenuation of chlorophenoxy herbicides under anaerobic condition are largely unknown.Here,the anaerobic degradation process of 2,4,5-trichlorophenoxyacetic acid(2,4,5-T),a typical chlorophenoxy herbicide,was investigated.Results The initial 52.5±2.3μM 2,4,5-T was completely degraded by a sediment-derived microbial consortium,with 3,4-dichlorophenol,2,5-dichlorophenol,3-chlorophenol(3-CP)and phenol being identified as the intermediate products.Reductive dechlorination of 3-CP to phenol and the subsequent elimination of phenol were the key transformation steps in the overall degradation process of 2,4,5-T.Amplicon sequencing suggested that Dehalobacter,Sulfuricurvum,Bacteroides,Acetobacterium,and Clostridium sensu stricto 7 might contribute to the transformation of 2,4,5-T to phenol,and Smithella,Syntrophorhabdus,Methanofollis and Methanosaeta likely cooperated to accomplish the complete mineralization of phenol.Conclusions This study reported the anaerobic degradation of 2,4,5-T via reductive dechlorination and the subsequent syntrophic metabolization of phenol,an intermediate product transformed from 2,4,5-T.Dehalobacter was identified as the organohalide-respiring population catalyzing the reductive dechlorination reaction.Syntrophorhabdus and methanogenic populations were likely involved in anaerobic phenol oxidation and facilitated the complete mineralization of 2,4,5-T.展开更多
基金supported by the Natural Science Foundation of China(42377133,42177220)with additional support from the Natural Science Foundation(Joint Fund)of Liaoning Province(2023JH2/101700354,2023JH2/101800044).
文摘Background Chlorophenoxy compounds represent a group of selective herbicides widely used around the world.Chlorophenoxy herbicides are toxic,chemically stable,and can migrate into groundwater through soil leaching,posing a significant threat to drinking water safety and human health.Chlorophenoxy herbicides in groundwater aquifers are subject to anaerobic processes;however,the pathway and microbiology involved in the attenuation of chlorophenoxy herbicides under anaerobic condition are largely unknown.Here,the anaerobic degradation process of 2,4,5-trichlorophenoxyacetic acid(2,4,5-T),a typical chlorophenoxy herbicide,was investigated.Results The initial 52.5±2.3μM 2,4,5-T was completely degraded by a sediment-derived microbial consortium,with 3,4-dichlorophenol,2,5-dichlorophenol,3-chlorophenol(3-CP)and phenol being identified as the intermediate products.Reductive dechlorination of 3-CP to phenol and the subsequent elimination of phenol were the key transformation steps in the overall degradation process of 2,4,5-T.Amplicon sequencing suggested that Dehalobacter,Sulfuricurvum,Bacteroides,Acetobacterium,and Clostridium sensu stricto 7 might contribute to the transformation of 2,4,5-T to phenol,and Smithella,Syntrophorhabdus,Methanofollis and Methanosaeta likely cooperated to accomplish the complete mineralization of phenol.Conclusions This study reported the anaerobic degradation of 2,4,5-T via reductive dechlorination and the subsequent syntrophic metabolization of phenol,an intermediate product transformed from 2,4,5-T.Dehalobacter was identified as the organohalide-respiring population catalyzing the reductive dechlorination reaction.Syntrophorhabdus and methanogenic populations were likely involved in anaerobic phenol oxidation and facilitated the complete mineralization of 2,4,5-T.
