Diflufenican is a widely used herbicide characterized by extreme environmental persistence, with a DT₉₀ of up to 1900 days. Its accumulation in agricultural soils poses ecological risks and requires the development of efficient bioremediation strategies. While microbial degradation is a promising approach, no previous studies have demonstrated the potential for diflufenican removal using soil bacterial isolates.

Agricultural soil from a diflufenican-treated field in Poland was screened for degradative microorganisms using enrichment culture techniques in mineral salt medium (MSM) supplemented with the herbicide. Four isolates with the highest biodegradation potential were identified via 16S rRNA sequencing as Pseudomonas sp. 10Kp8 - A1, Pseudomonas chlororaphis subsp. aureofaciens B19 - A2, Pseudomonas baetica JZY4-9 - C1, and Streptomyces atratus ROA017 - D1. Biodegradation efficiency was assessed in MSM and sterile horticultural soil, comparing individual strains with a quadruple consortium. Herbicide residues and selected diflufenican metabolites were quantified by GC-MS/MS.

In MSM, the D1 strain achieved 70% degradation after 21 days, while the consortium reached 74%. In soil, D1 removed 79% of herbicide and the consortium 82% within 28 days. The metabolite, 2-(3-trifluoromethylphenoxy) nicotinic acid, was detected in all MSM and soil samples analyzed.

This study presents the first evidence of diflufenican biodegradation by bacteria, highlighting both the D1 strain and a consortium as promising candidates for bioremediation. The superior performance of the consortium suggests synergistic interactions enhance degradation. Given their safety profile and the existing agricultural uses of related strains, these isolates have strong potential for integration into sustainable soil remediation practices.