Phenolic acids in root exudates mediate laccase-induced formation of estrogen precipitation co-polymers

Endocrine-disrupting estrogens, such as 17β-estradiol (E2) and bisphenol A (BPA), are commonly found in agroecosystems, posing substantial risks to crop productivity and public health. While laccase-induced polymerization transfer is an effective strategy for estrogen remediation, the interactive effects of living crop root-released exudates (e.g., sugars, phenolic acids, amino acids) on this enzymatic process remain largely unclear. Here, we employed artificial root exudates (AREs) containing environmentally relevant concentrations of key components to systematically dissect the regulatory roles of distinct root-exuded fractions in laccase-induced estrogen conversion. Compared to the ARE-deficient group, phenolic and amino acids in AREs collectively suppressed laccase-induced estrogen self-polymerization. Notably, phenolic acids exerted a distinct, complementary effect by mediating radical-controlled C-C and C-O-C co-polymerization between estrogen molecules and ARE components, resulting in robust precipitation of co-polymeric products. These precipitation co-polymers were assembled from moieties containing phenolic -OH, -COOH, and aryl functional moieties, exhibiting high structural complexity, morphological diversity, and dense packing that endow them with unique physicochemical properties. Furthermore, we selected maize (Zea mays L.) as a model crop and experimentally demonstrated that laccase reduced the estrogen pollution risks in maize seedlings by catalyzing rapid pollutant polymerization in the rhizosphere solution, effectively blocking root uptake and subsequent translocation to above-ground shoot tissues. Relative to the laccase-free group, laccase treatment significantly reduced E2 levels in maize roots and shoots by 59.26% and 54.78%, respectively, following 5-day exposure to 20 μmol·L⁻¹ E2. These findings offer a robust enzyme-induced polymerization way for mitigating estrogen pollution in agroecosystems, with critical implications for ensuring crop safety and agricultural sustainability.