Metagenomic and enzymatic mechanisms underpinning efficient water treatment of 2-ethylhexyl diphenyl phosphate (EHDPP) by the microbial consortium 8-ZY

The ubiquitous presence, potential toxicity, and persistence of 2-ethylhexyl diphenyl phosphate (EHDPP) in the environment have raised significant concerns. In this study, we successfully isolate a novel microbial consortium, named 8-ZY, and we demonstrate its remarkable ability to degrade EHDPP using an extremely low concentration of the inoculate. A total of 11 degradation metabolites were identified, including hydrolysis, hydroxylated, methylated, glucuronide-conjugated, and previously unreported byproducts, enabling us to propose new transformation pathways. Further, we unveiled the active members of the microbial consortium 8-ZY during the degradation of EHDPP. We observed the presence of diverse active populations, which included Bradyrhizobium, Rhodopseudomonas, Sphingomonas, Hyphomicrobium, Chitinophaga, Aminobacter, and Ralstonia. A metagenomic analysis revealed the presence of genes that encode phosphatase, phosphodiesterase, cytochrome P450, and hydroxylase enzymes, thus indicating their crucial role in EHDPP degradation. Furthermore, we successfully isolated Burkholderia cepacia ZY1, Sphingopyxis terrae ZY2, and Amycolatopsis ZY3 from the 8-ZY consortium, confirming their significance in EHDPP degradation and metabolite formation. These findings underscored the diversity of strains and functional genes responsible for the transformation of EHDPP within the consortium 8-ZY, highlighting the essential role of synergistic interactions during EHDPP biodegradation processes. Molecular docking and dynamics simulation suggested that alkaline phosphatase, cytochrome P450, and hydroxylase stably bonded to EHDPP within their respective active pockets, targeting distinct sites on the EHDPP molecule. These findings provide a comprehensive understanding of the transformation mechanisms of OPEs and contribute valuable insights into their fate in the environment.