High uptake carboxyl-functionalized porous β-cyclodextrin polymer for selective extraction of lysozyme from egg white

Lysozyme is widely used in medical, food and industrial fields due to its bacteriolytic effect and thus it is significant to design and develop a specific adsorbent with high adsorption capacity and selectivity for lysozyme. Inspired by the high uptake capacity of tetrafluoroterephthalonitrile-crosslinked porous β-cyclodextrin polymers (P-CDPs) and the noncovalent interaction between lysozyme and carboxyl groups, the carboxyl-functionalized P-CDPs (P-CDP-COO − ) were synthesized by base-catalysed hydrolysis of nitrile group in P-CDPs to carboxyl. Porous structure, large extent of carboxylic functional groups, cyclodextrin's preventing aggregation, and negatively charged make P-CDP-COO − possess an outstanding adsorption capability for lysozyme. The maximum saturated adsorption capacity reaches 1520 mg g −1 , which is much better than the parent polymer and other reported materials. The as-prepared material was successfully utilized for the selective extraction of lysozyme from egg white.