Facile fabrication of chitin-glucan nanofibers from four edible mushroom species using deep eutectic solvent and their adsorption characterization.

Mushrooms are an underexplored source of chitin-based biopolymers. Here, chitin-glucan nanofibers (CGNFs) were fabricated from four widely consumed mushrooms: Flammulina velutipes, Agaricus bisporus, Lentinula edodes, and Pleurotus eryngii. Chitin-glucan complexes (CGCs) obtained from different species exhibited distinct chemical compositions and morphologies; notably, L. edodes produced CGC with the highest recovery rate (25.0%). The following acidic deep eutectic solvent treatment of CGCs enabled their dissolution and esterification, and the subsequent ethanol regeneration enabled efficient recovery of CGNFs (52.6%-72.3%) from dry CGCs. The resulting CGNFs showed species-dependent differences in diameter, surface charge, colloidal stability, and thermal behavior. Adsorption experiments using a model cationic dye, methylene blue, revealed that the species- and anatomical part-dependent adsorption behavior of CGNFs was dominated by charge-driven interactions. This work demonstrates a broadly applicable route for converting diverse mushroom resources, particularly L. edodes stipes, into functional chitin-based nanomaterials.