Genome-resolved metagenomics reveals potential biochemical capabilities of a microbial community in an industrial wastewater membrane bioreactor during performance deterioration and recovery

Abstract

This study investigates the microbial community composition and biochemical capabilities within a membrane bioreactor (MBR) system treating industrial wastewater during two operational states: a period of marked performance deterioration and a subsequent early recovery phase. The MBR system experienced a prolonged decline in treatment performance, with Total Organic Carbon (TOC) removal efficiency decreasing from approximately 90% to approximately 70% and effluent Biochemical Oxygen Demand (BOD) increasing to more than 70 mg/L. Metagenomic sequencing and subsequent analysis unveiled distinct shifts in microbial community composition and functional potential during these operational states. A total of 51 Metagenome-Assembled Genomes (MAGs) were reconstructed and characterized, revealing microbial populations associated with Pseudomonadota and Bacteroidota . These populations exhibited putative metabolic capabilities associated with nitrogen cycling, sulfur metabolism, and degradation of recalcitrant aromatic compounds. Key taxa enriched during the early recovery condition contained genes associated with nitrogen fixation and sulfur oxidation. These findings provide genome-resolved insights into microbial community composition and predicted functional potential during contrasting MBR operational states and may inform future investigations of industrial wastewater treatment systems.