Linkages between core microbiome and functional convergence during artificially selecting microbial communities for...

The escalating prevalence of benzotriazole (BTR), an emerging refractory organic pollutant, has drawn significant attention for the development of efficient bioremediation solutions. Although the construction of microbial consortia represents a promising strategy, the intrinsic relationship between community succession and functional features during artificial selection remains poorly understood. To address this, this study engineered two distinct microbial consortia from activated sludge using a top-down selection strategy in sequencing batch reactors fed with increasing BTR concentrations. While the two consortia evolved along divergent taxonomic pathways, they exhibited remarkable functional convergence, maintaining consistently high BTR transformation (>96%) and chemical oxygen demand (>75%) removal efficiencies. This robust performance under the stringent condition of BTR as the sole carbon source highlighted their significant adaptive potential. Metagenomic analysis further attributed this functional stability to the principle of functional redundancy, wherein taxonomically distinct keystone species (e.g., Nocardioides and Methylobacterium) harbored functionally analogous gene clusters. Additionally, multiple congeneric species (e.g., MAG.480 and MAG.17) within the Bacteroidota phylum exhibited significant divergence in their degradation gene repertoires. These findings not only advance ecological understanding of microbiome-mediated BTR biodegradation but also provide a foundation for the rational design and optimization of high-performance bioremediation consortia.