Amyloid-Like Lysozyme@Chitosan Composite for the Separation of Organic Pollutants

There is an urgent demand for efficient adsorbents to remove persistent organic pollutants from wastewater. Unlike previous protein‑based composites used mainly for metal cation separation, this study develops a positively charged amyloid‑like lysozyme@chitosan composite (PTL@CS) by incorporating chitosan into lysozyme, specifically targeting anionic dyes such as Congo red (CR). PTL@CS exhibits a stable structure enriched with synergistic functional groups (e.g., carboxyl, hydroxyl, amino) and demonstrates amyloid-like aggregation, confirmed by thioflavin T (ThT)/8-Anilino-1-naphthalenesulfonic acid (ANS) fluorescence assays, Fourier transform infrared (FTIR), and laser scanning confocal microscopy (LSCM). The material achieves exceptional CR adsorption capacity (up to 801 mg·g − 1 ), fitting the pseudo-second-order kinetics and the Langmuir isotherm models, indicating chemisorption-dominated monolayer adsorption. PTL@CS maintains high adsorption efficiency under acidic to neutral pH conditions as well as in complex ionic environments, exhibits excellent reusability, and shows low cytotoxicity toward IMR‑90 and human umbilical vein endothelial cells (HUVEC). These attributes underscore its potential as a sustainable, selective, and biocompatible adsorbent for next-generation water purification. Graphical Amyloid-like lysozyme@chitosan composite (PTL@CS) efficiently removes organic pollutants from water without causing environmental pollution, offering high adsorption capacity and reusability.