Enzymatic conjugation-deconjugation processes could accelerate the leaching of hydrophobic plastic additives

초록

The leaching of plastic additives is fundamental to assessing their environmental risk, yet the role of biofilmmediated biotransformation in this process remains poorly understood. This study investigates the influence of enzymatic conjugation (glucuronidation) on the leaching kinetics of UV stabilizers from low-density polyethylene (LDPE) fibers. By combining leaching experiments with a kinetic model, we identified distinct acceleration mechanisms governed by additive hydrophobicity. For highly hydrophobic benzotriazoles (UV-327 and UV-328), glucuronidation enhanced leaching by 20-28% relative to controls by accelerating mass transfer across the aqueous boundary layer (ABL). For moderately hydrophobic benzophenone-3 (BP-3), leaching increased by 289% as enzymatic activity sustained the concentration gradient by acting as a bulk-phase sink. These results demonstrate that enzymatic conjugation-deconjugation processes can substantially enhance the release of hydrophobic additives. As a result, abiotic models may underestimate the leaching of plastic-associated chemicals in biologically active environments.

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