Tetrabromobisphenol A biotransformation in aged soil: Mechanism analysis induced by root exudates during rhizoremediation of Helianthus annus

Rhizoremediation, recognized as a progressive strategy for the removal of organic pollutants in soil, prominently focused on the influence of root exudates-induced alterations within the rhizosphere on the bioavailability and transformation of pollutants. However, the influence of root exudates on the ultimate fate of tetrabromobisphenol A (TBBPA) in soil remains unclear. The current study embarked on a comprehensive examination of the biotransformation process and underlying mechanisms of TBBPA driven by root exudates of Helianthus annus in rhizospheric soil. The pot experiment underscored the constructive impact of root exudates on enhancing the TBBPA dissipation efficiency within lab-controlled, with the increments of 18.77 %∼38.64 %. The core bacterial players responsible for TBBPA biotransformation were identified, with the prominent genus being Saccharibacteria_genera_incertae_sedis, unclassified_Sphingomonadaceae, and Parcubacteria_genera_incertae_sedis. In rhizospheric soil, a comprehensive analysis disclosed the presence of 20 different biotransformation products of TBBPA. Notably, root exudates were found to predominantly drive the reductive debromination pathway. This study provided for the first concrete evidence that root exudates can promote the desorption of TBBPA from soils. The current study aimed to decipher the molecular mechanisms in biotransformation process of TBBPA mediated by root exudates, and also provided reference for the environmental behavior of organic pollutants induced by root exudates. [Display omitted] •Root exudates-mediated dissipation efficiency of TBBPA increased by 38.64 %.•Effect of actual root exudates on TBBPA biotransformation was first investigated.•Root exudates mainly promote the reductive debromination of TBBPA in soil.•Actual root exudates significantly enhanced the TBBPA desorption from soil particles.