Construction Of BDE-47 Genetically Engineered Bacteria And Soil Microecological Effects

Polybrominated diphenyl ethers(PBDEs)are widely used in electronic devices as a new type of flame retardant,which BDE-47 is one of the most toxic and has a potential threat to human beings and the ecological environment.Indigenous dominant bacterium(Shewanella oneidensis)WT-G was screened from the soil of an electronic waste dismantling site in Taizhou City,Zhejiang Province,to construct a genetically engineered bacteria,based on the BDE-47 aerobic degradation gene analyzed in the laboratory and GB-2 as the donor bacteria.The genetic stability and degradation stability of genetically engineered bacteria were verified,the remediation effect of genetically engineered bacteria on BDE-47 contaminated soil and its soil microecological effects were explored.The results of the study are as follows:(1)From BDE-47 contaminated soil collected in the laboratory pre-laboratory,an indigenous dominant strain was screened.Morphological observation,physiological and biochemical characteristics,and molecular biology all enabled the identification of the strain WT-G as Shewanella oneidensis.WT-G’ s growth lag is brief,with a swift growth period within 20 hours,a steady plateau at 60 hours,and a gradual decrease around 100 hours..(2)With GB-2 as the donor bacteria and the Ant ABC gene cluster as the target gene,the suicidal expression vector p UT-mini-Tn5 was connected,and the three-parent connection was legally transferred into the indigenous dominant recipient bacteria to construct a genetically engineered bacterium WT-G-Ant ABC,tentatively named G-Ant.Artificial passage has verified that the genetically engineered bacteria can be stably inherited.The results showed that the degradation rate of the passaged strains was very good,with an average of 72～76% and the best of 76.78%.Gene abundance testing showed that genetically engineered bacteria could be stably inherited and efficiently expressed during passage.(3)The recombinant strain represented by G-Ant had a degradation rate of 47.15%of BDE-47 within 30 days.The degradation rate of donor bacteria GB-2 in remediating1500 ng/g BDE-47 contaminated soil in the same time was 41.98%,which showed that the application of genetically engineered bacteria promoted the degradation of BDE-47 in soil.An examination of G-Ant’ s influence on BDE-47 was conducted through the analysis of soil physical and chemical characteristics,enzyme activity,and microbial population in the soil.Results demonstrated that G-Ant treatment proved to be more efficacious than GB-2.G-Ant can maintain certain growth advantages in contaminated soil and has certain environmental adaptability.The genetically engineered bacteria of BDE-47 degradation improved the microbial aerobic degradation efficiency of BDE-47 and maintained certain growth advantages in BDE-47 contaminated soil.Compared with the donor bacterium GB-2,genetically engineered bacteria G-Ant is more conducive to the remediation of contaminated soil.This study not only provides mycoplasm resources for the aerobic degradation of BDE-47,but also provides a reference for the remediation of contaminated soil of persistent organic pollutants.