Metagenomic Analysis of the Antibiotic Resistance Risk between an Aerobic and Anaerobic Membrane Bioreactor

Abstract

Membrane bioreactors are advanced treatment technologies that, compared to conventional treatment processes, are expected to reduce antibiotic resistance spread in the environment due to their superior biomass retention. In this study, metagenomic sequencing was used to assess the response of the microbial community and antibiotic resistance profile of an aerobic membrane bioreactor (AeMBR) and an anaerobic membrane bioreactor (AnMBR) operated in parallel, treating identical synthetic wastewater supplemented with select antibiotics. Our results revealed a greater antibiotic impact on the microbial community and antibiotic resistance gene (ARG) proliferation within the AeMBR compared to the AnMBR. Moreover, antibiotic loading elicited a more pronounced disruption of the microbial diversity of the AeMBR biomass and effluent intracellular DNA compared to its AnMBR counterpart. Under antibiotic loading, the AeMBR effluent enriched ARGs in the form of antibiotic-resistant bacteria, while the AnMBR effluent enriched a wide set of extracellular ARGs across a broad spectrum of resistance classes. These results provide a theoretical basis for process selection and controlling the spread of ARGs during wastewater management.