Full metadata
Title
Biodegradation of Surfactants in the O2-based MBfR and the Impacts on the Microbial Community and Antimicrobial-resistance Genes
Description
While most household surfactants are biodegradable in aerobic conditions, their presence in a microbiological treatment process can lead to the proliferation of antimicrobial-resistance genes (ARG) in bacteria, such as Pseudomonas aeruginosa. Surfactants can be cationic, anionic, or zwitterionic, and these different classes may have different effects on the proliferation of ARG. This study evaluated how the three classes of surfactants affected the microbial community’s structure and ARG in O2-based membrane biofilm reactors (O2-MBfRs) that provided at least 98% surfactant removal. Cationic cetrimonium bromide (CTAB) had by far the strongest impact with highest ARG abundance in the biofilm. In particular, Pseudomonas and Stenotrophomonas, the two main genera in the biofilm treating CTAB, were highly correlated to the abundance of ARG for efflux pumps and antibiotic inactivation. CTAB also promoted potential of horizontal gene transfer (HGT) of ARG. Combining results from the metabolome and metagenome identified four possible pathways for CTAB biodegradation. Of special important is a new pathway: β-carbon oxidation of CTAB to produce betaine. An insufficient nitrogen source could lead to irreversible ARB and ARG enrichment in the MBfR biofilm. Finally, a two-stage O2-MBfR successfully removed a high concentration (730 mg/L) of CTAB: Partial CTAB removal in the Lead reactor relieved inhibition in the Lag reactor. Metagenomic analysis also revealed that the Lag reactor was enriched in genes for CTAB and metabolite oxygenation.
Date Created
2023
Contributors
- Zheng, Chenwei (Author)
- Rittmann, Bruce (Thesis advisor)
- Delgado, Anca (Committee member)
- Krajmalnik-Brown, Rosa (Committee member)
- Lai, Yen-Jung (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
132 pages
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.2.N.187746
Level of coding
minimal
Cataloging Standards
Note
Partial requirement for: Ph.D., Arizona State University, 2023
Field of study: Civil, Environmental and Sustainable Engineering
System Created
- 2023-06-07 12:21:19
System Modified
- 2023-06-07 12:21:25
- 1 year 5 months ago
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