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• PFOA had no significant effect on the nitrogen removal efficiency of anammox system. • PFOA could bind with proteins in EPS with multiple binding sites. • PFOA reduced the absolute abundances of functional bacteria and genes. • PFOA changed the metabolic pathways of anammox consortia. Perfluorooctanoic acid (PFOA) is ubiquitous in aquatic environment, posing serious threats to human health, while the potential of anaerobic ammonium oxidation (anammox) process in treating PFOA-containing wastewater and the response mechanism of anammox consortia to PFOA remain unknown. In this study, the comprehensive effects of PFOA on anammox granules and their interaction mechanism were investigated based on molecular simulation and metabolomic analysis. The environmental concentrations (≤2.0 mg/L) of PFOA had no impact on the anammox process performance. However, microbial consortia structure and functional gene abundances changed under the exposure of PFOA. By contrast, Prokaryotes were more sensitive to PFOA than eukaryotes. In addition, PFOA regulated microbial metabolic pathways, including amino acid metabolism and nucleotide metabolism, by changing the cell energy allocation strategy. Molecular docking simulation suggested that the effects of PFOA on key proteins in anammox bacteria were significantly different. These findings provide insights into the interaction between anammox consortia and PFOA, and further promote the implementation of anammox process to treat fluorine-containing wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propranolol and doxycycline triggered oxidative stress and MGE enrichment. • Doxycycline induced the higher frequency of HGT than propranolol. • Propranolol could also promote HGT by upregulating relevant functional genes. • Anammox consortia upregulated amino acid metabolism in responding to propranolol stress. Given that antibiotic resistance genes (ARGs) become emerging pollutants, their accumulation and transfer caused by extensive use of antibiotic and non-antibiotic drugs raise concerns. In contrast, the impacts of non-antibiotic drugs have been largely overlooked, and their regulation mechanism in anammox system remains unclear. In this study, the single and combined effects of typical antibiotic (doxycycline) and non-antibiotic drug (propranolol) on anammox consortia were evaluated and compared from process performance, community succession, metabolic and gene regulation perspectives. Significant reduction in the nitrogen removal efficiency (49.0 ± 0.5%) was only observed in the anammox process stressed by propranolol and doxycycline, but it was reversible. Metabolome results showed that anammox consortia upregulated amino acid metabolism under propranolol stress, while the abundance of pyrimidine and purine metabolic pathways significantly increased under doxycycline and multidrug stress. Microorganisms adapted to these stresses by changing the utilization preference for metabolites. Metagenomic analyses indicated that doxycycline and propranolol induced the high frequency of gene transfer through increasing oxidative stress level, membrane permeability, pili and efflux pumps. Significant correlations between ARGs and mobile genetic elements (MGEs), especially int I1, demonstrated the conjugative transfer of ARGs. Furthermore, structural equation models showed that microbial community, bacterial metabolism, MGEs, reactive oxygen species (ROS) and corresponding SOS response were key driving factors for ARGs transfer in the anammox systems. These findings fill the gap in the effect of non-antibiotic drugs on anammox system and their regulation mechanism, which further provides a theoretical guidance for anammox-based process to treat multidrug-containing wastewater. [ABSTRACT FROM AUTHOR]