Researchers have identified an effective microbial consortium capable of fully degrading a widely used herbicide, offering a promising, eco-friendly approach to tackling agricultural soil pollution. The discovery is made in response to increasing growing concern over the long-term impact of herbicide residues on soil ecosystems, food quality, and overall environmental safety.

The study, led by Dr. XU Mingkai’s team at the Institute of Applied Ecology, Chinese Academy of Sciences, focused on acetochlor, a commonly used amide herbicide. While effective for weed control, acetochlor is notorious for its persistence in soil and its toxicity to non-target organisms. Conventional remediation methods remain limited in scope and sustainability. By contrast, bioremediation, defined as the use of microorganisms to degrade pollutants, has emerged as the most feasible and environmentally sound strategy, especially with the advent of synthetic microbial consortium technology.

The research team successfully enriched a microbial consortium from acetochlor-contaminated farmland, which they named AT1. Under optimised conditions, AT1 was able to almost completely degrade acetochlor at concentrations as high as 1,000 mg/L within twelve days, demonstrating a performance superior to any previously reported strain or system. The results were recently published in Journal of Environmental Management under the title "Biodegradation of acetochlor by microbial consortium AT1: microcosm centric microbiomic-metabolomics mechanisms and environmental remediation feasibility." 

High-throughput 16S rRNA gene sequencing revealed that microbial diversity within AT1 decreased over the course of acetochlor degradation, with microbial community structure and function shifting significantly. Through microbiomic-metabolomic analysis, the researchers uncovered a novel degradation pathway for acetochlor driven by synergistic metabolic interactions among different microbes.

In this pathway, Pseudomonas initiated N-dealkylation, Diaphorobacter catalysed amide bond hydrolysis, and Sphingomonas contributed to both carboxylation and hydroxylation of the aromatic ring. Together, these microbes broke down acetochlor into smaller intermediates such as 2,6-dimethylaniline, resorcinol, and phenol, which were further mineralised and funnelled into the tricarboxylic acid (TCA) cycle—a central energy-yielding pathway in microbial metabolism.

Beyond mechanistic insights, the research team also validated the consortium’s potential in a microcosm experiment, confirming that AT1 effectively reduced acetochlor residues in contaminated soil. 

These findings not only enrich the scientific understanding of amide herbicide degradation but also provide practical tools for developing green bioremediation technologies to address non-point source pollution in agricultural environments.

By harnessing the complementary metabolic capabilities of multiple microbial species, this study marks a significant step forward in sustainable pollution control. It highlights the growing importance of microbial engineering in managing chemical residues and safeguarding environmental and food safety.

Figure 1. Changes in microbial diversity and community structure during degradation of acetochlor by consortium AT1 (Image by DAI Yumeng)