Anaerobic membrane bioreactor-based treatment of poultry slaughterhouse wastewater: Microbial community adaptation and antibiotic resistance gene profiles

Abstract

Anaerobic membrane bioreactors (AnMBRs) are becoming an increasingly attractive basis for industrial wastewater treatment. Slaughterhouse wastewaters in particular are complex waste streams that have high energy recovery potential. The effectiveness of AnMBR-based treatment for such wastewaters, however, is directly dependent on the adaptability of their functional microbial communities. The present study investigated changes in the microbial consortia of a lab-scale AnMBR upon introduction of a poultry slaughterhouse wastewater (PSW) source. The work also evaluated the AnMBR’s effluent for potentially pathogenic bacteria and antibiotic resistance-related elements. 96% COD removal and 73% biogas methane content were achieved, making net energy recovery from the system possible. Microbial communities of the reactor biomass shifted notably during the course of PSW treatment, with the family Syntrophaceae increasing in relative abundance from 2% to 24%. This was accompanied by a change in the dominant methanogenic groups from hydrogenotrophic (Methanocorpusculum) to acetoclastic (Methanothrix). Multiple antibiotic resistance genes detected in the effluent (including sul1, sul2, and ampC) peaked by over an order of magnitude immediately after PSW introduction, with a notable decline thereafter. This coincided with a similar peak in intI1, suggesting that a horizontal gene transfer event was likely induced. This work provides insight into the microbial groups that can enhance treatability of PSW by AnMBR while also advancing the potential for abatement of emerging microbial risks.