TY - JOUR
T1 - Distinct effects of hypochlorite types on the reduction of antibiotic resistance genes during waste activated sludge fermentation
T2 - Insights of bacterial community, cellular activity, and genetic expression
AU - Luo, Jingyang
AU - Huang, Wenxuan
AU - Zhang, Qin
AU - Wu, Yang
AU - Fang, Fang
AU - Cao, Jiashun
AU - Su, Yinglong
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/5
Y1 - 2021/2/5
N2 - The effectiveness of hypochlorites (NaClO and Ca(ClO)2) on the reduction of antibiotic resistance genes (ARGs) during waste activated sludge (WAS) fermentation was determined by the quantitative PCR. NaClO and Ca(ClO)2 exhibited distinct effects on ARGs fates. Ca(ClO)2 was effective in removing all investigated ARGs, and the efficiency was highly dose-dependent. Unexpectedly, the NaClO treatment attenuated ARGs with lower efficiency and even caused the propagation of certain ARGs (i.e., aadA1 and tetQ) at higher doses. The extracellular polymeric substances dissolution and membrane integrity suggested that unstable NaClO had acute effects on bacteria initially, while it was ineffective to further attenuate ARGs released from hosts due to the rapid consumption of oxidative ClO-. Without lasting and strong oxidative stress, the microbial activities of tolerant ARGs hosts will partially recover and then contribute to the ARGs dissemination across genera. In contrast, solid-state Ca(ClO)2 was slowly released and exhibited prolonged effects on bacteria by disrupting cell membranes and removing the susceptible ARGs released from hosts. Furthermore, bacterial taxa-ARG network analysis indicated that Ca(ClO)2 reduced the abundance of potential hosts, and the metabolic pathway and gene expression related to ARGs propagation were significantly downregulated by Ca(ClO)2, which contributed to efficient ARGs attenuation.
AB - The effectiveness of hypochlorites (NaClO and Ca(ClO)2) on the reduction of antibiotic resistance genes (ARGs) during waste activated sludge (WAS) fermentation was determined by the quantitative PCR. NaClO and Ca(ClO)2 exhibited distinct effects on ARGs fates. Ca(ClO)2 was effective in removing all investigated ARGs, and the efficiency was highly dose-dependent. Unexpectedly, the NaClO treatment attenuated ARGs with lower efficiency and even caused the propagation of certain ARGs (i.e., aadA1 and tetQ) at higher doses. The extracellular polymeric substances dissolution and membrane integrity suggested that unstable NaClO had acute effects on bacteria initially, while it was ineffective to further attenuate ARGs released from hosts due to the rapid consumption of oxidative ClO-. Without lasting and strong oxidative stress, the microbial activities of tolerant ARGs hosts will partially recover and then contribute to the ARGs dissemination across genera. In contrast, solid-state Ca(ClO)2 was slowly released and exhibited prolonged effects on bacteria by disrupting cell membranes and removing the susceptible ARGs released from hosts. Furthermore, bacterial taxa-ARG network analysis indicated that Ca(ClO)2 reduced the abundance of potential hosts, and the metabolic pathway and gene expression related to ARGs propagation were significantly downregulated by Ca(ClO)2, which contributed to efficient ARGs attenuation.
KW - Anaerobic fermentation
KW - Antibiotic resistance genes (ARGs)
KW - Attenuation
KW - Hypochlorite treatment
KW - Waste activated sludge (WAS)
UR - https://www.scopus.com/pages/publications/85091234304
U2 - 10.1016/j.jhazmat.2020.124010
DO - 10.1016/j.jhazmat.2020.124010
M3 - 文章
C2 - 33265039
AN - SCOPUS:85091234304
SN - 0304-3894
VL - 403
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 124010
ER -