Effect of zero valent iron on antibiotic resistance gene in nitrifying sludge under 17α-ethinylestradiol stress
The prevalence of antibiotic resistance genes(ARGs)has been widely concemed by the worldwide researchers.However,the effect of zero valent iron(ZVI)on ARGs in nitrifying sludge has been rarely studied.A nitrifying sludge sequencing batch reactor was used to remove 17α-ethinylestradiol(EE2).The effect of ZVI on ARGs in the process of EE2 removal by nitrifying sludge was investigated based on metagenome sequencing,and the potential mechanism was analyzed by combining with the structure of bacterial community.The results showed that the abundance of ARGs increased by 724.42TPM(transcripts per million)during the removal of EE2,and ZVI reduced the increasing trend of ARGs abundance.EE2 and ZVI changed the distribution of ARGs subtypes,but had no significant effect on the types and subtypes amount of ARGs.The abundance of ARGs belonging to high-risk ranks(Q1 and Q2)increased by 555.75,151.08TPM in the treatment of EE2,but ZVI reduced the resistance risk.Multidrug was the most abundant high-risk(Q1 and Q2 rank)ARGs in nitrifying sludge,accounting for 49.23％.Microbial community was an important driving factor for ARGs in nitrifying sludge.Some bacteria,such as Sphingopyxis,were significantly associated with multiple ARGs positively,and might be the common potential hosts of multiple ARGs.This study provides a scientific basis and theoretical guidance for ZVI to reduce ARGs and resistance risks in the treatment of emerging pharmaceutical contaminants by biological nitrogen removal process.
万方数据
维普
