Mechanistic insights into designing synthetic microbial communities to accelerate herbicide biodegradation in soils

Persistent herbicide residues, including atrazine, metolachlor, fomesafen, etc., pose significant threats to soil microbial diversity, nutrient cycling and long-term agroecosystem sustainability. Conventional single-strain bioremediation frequently results in incomplete degradation, accumulation of toxic intermediates and limited ecological fitness under field conditions. Synthetic microbial communities (SynComs) provide a promising alternative by harnessing metabolic division of labor, cross-feeding and niche complementarity. This review synthesizes advances from 2019 to 2025, demonstrating that rationally designed SynComs substantially outperform single strains or natural attenuation, with most evidence derived from laboratory and soil microcosm studies conducted in non-sterile agricultural soils (e.g., loamy soils with moderate organic matter content and neutral pH). SynComs generally exhibit enhanced degradation performance compared to single strains, owing to metabolic complementarity and cooperative interactions. Reported improvements vary widely across studies, ranging from 1.5 to 3-fold, in specific optimized cases, depending on the pollutants, community design and experimental conditions. Enhanced performance is attributed to: (1) distribution of catabolic steps across community members, (2) cooperative detoxification of intermediates, and (3) improved resilience via mutualistic interactions. Emerging tools, including high-throughput isolation, multi-omics profiling, genome-scale metabolic modelling and machine-learning guided assembly, enable increasingly predictive SynCom design. To support translation from laboratory optimization to field application, we propose two complementary frameworks: (1) the Evidence-Weighted SynCom Strategy (EWSS), which links herbicide structure to essential catabolic and supportive traits; and (2) the SynCom Readiness Level (SRL1–9), which tracks consortium maturity from mechanistic discovery to field-scale validation. While field-scale validation remains limited, existing mesocosm and field studies consistently demonstrate improved in-situ dissipation relative to natural attenuation.