Removal of Bisphenol A Using Laccase-catalyzed Electro-oxidation in the Presence of Humic Acid

Bisphenol A (BPA) is an endocrine-disrupting chemical that has caught a lot of attention recently due to its toxicity and ubiquitous presence in the environment. Therefore, removal of BPA from contaminated environments such as water is of high importance. In this study, we prepared an alginate/pectin anode containing immobilized laccase and applied the anode in an electro-enzymatic oxidation system for BPA degradation. After 4 h, the laccase-alginate/pectin system demonstrated a much higher BPA removal efficiency (95%) than the similar system without immobilized laccase (50%, control system). The effects of humic acids (HA) on BPA degradation were also observed. HA might have accelerated the laccase-catalyzed coupling reaction between BPA and reactive radical intermediates, which resulted in increased BPA removal efficiency (92% after 150 min). It was demonstrated that laccase immobilization on an alginate/pectin electrode could greatly enhance BPA removal via electro-oxidation. Humic acids which are abundantly present in nature can also make this removal process faster. Overall, this study highlights the great application potential of laccase-immobilized bioelectrodes for BPA removal in conditions close to real life scenarios.