Preparation of Chitin–Glucan Complex Aerogel from Mycelium Waste with Tunable Properties

TL;DR

Researchers developed a method to dissolve and process chitin–glucan complex from fungal waste into aerogels with potential biomedical and environmental uses.

Contribution

First-time dissolution of CGC in a NaOH/urea system and fabrication of cytocompatible aerogels from mycelium waste.

Findings

CGC was successfully dissolved in a NaOH/urea solvent at ambient temperature in 5 minutes.

CGC aerogels showed no cytotoxicity and have potential for biomedical and environmental applications.

Structural integrity and covalent linkage of CGC were confirmed using FTIR, NMR, and electron microscopy.

Abstract

Chitin–glucan complex (CGC) is a naturally occurring heteropolysaccharide in which chitin chains are covalently integrated with β-glucans, forming a rigid structural framework in fungal and yeast cell walls. CGC exhibits a broad spectrum of functional properties, including antimicrobial, antioxidant, adsorption, and tissue-regenerative activities; however, its technological exploitation has been severely constrained by its intrinsic insolubility in water and most common solvents. In this work, CGC was isolated from Aspergillus niger mycelial biomass and, for the first time, completely dissolved in a precooled aqueous NaOH/urea solvent system (12 wt.% NaOH, 8 wt.% urea) within 5 min at ambient temperature, yielding a clear and stable solution. The influence of alkali concentration on dissolution efficiency and solution stability was systematically examined. Structural integrity and covalent linkage between chitin/chitosan and glucan segments were confirmed using FTIR spectroscopy, two-dimensional NMR, and electron microscopy. The degree of deacetylation determined by NMR was approximately 25%. Rheological analysis revealed concentration- and temperature-dependent sol–gel transitions, with well-defined storage and loss moduli during gelation. Crosslinking with epichlorohydrin enabled the fabrication of lightweight, highly porous three-dimensional CGC aerogels. In vitro cytocompatibility studies using NIH 3T3 fibroblasts demonstrated no detectable cytotoxicity over 72 h. These results establish a green, efficient route for CGC dissolution and processing and highlight the promise of CGC aerogels as sustainable biomaterials for biomedical and environmental applications.

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