Pickering Emulsion Biocatalysis with Engineered Living Cells for Degrading Polycarbonate Plastics

The efficient degradation of plastics remains a pressing environmental challenge due to their inherent resistance to breakdown. While biocatalysis offers a promising approach for sustainable and effective plastic degradation, the inherently low solubility of plastics in aqueous systems severely limits the efficiency of enzymatic reactions. To address this issue, we developed a biocompatible polymer coating strategy to engineer living cell surfaces, enabling the stabilization of Pickering emulsions for over 192 h and significantly enhancing plastic accessibility to biocatalysts. Leveraging this platform, Escherichia coli (E. coli) cells containing overexpressed Candida antarctica Lipase B performed well by dispersing at the emulsion interface of water and toluene, facilitating the efficient biodegradation of polycarbonate (PC) plastics. Under optimized reaction conditions (pH 9, 45 °C), this Pickering emulsion system achieved efficient PC degradation, producing up to 4.5 mm bisphenol A within 72 h-far exceeding the performance of biphasic systems using native E. coli cells. The findings highlight the transformative potential of surface-engineered whole-cell catalysts in addressing environmental challenges, particularly plastic waste remediation.