Fungal Chitin as a Renewable and Abundant Alternative to Crustacean Chitin

A. Zannat, J.L. Shamshina
Texas Tech University,
United States

Keywords: Chitin, Fungal chitin, Chitin-glycan complex, Separation

Summary:

Chitin is a versatile biopolymer that may be isolated from many sources. Crustacean biomass is one of the most well-known sources while mushrooms have received less research attention. Mushrooms are included in the kingdom of fungi, hence, this chitin source is plant-based, free of allergens, and does not vary with the seasons or regions. Fungal chitin could constitute a viable alternative to crustacean chitin. However, in mushrooms, chitin is covalently bonded with its copolymers, branched 1,3/1,6-ß-D-glucans, forming chitin-glucan complex (CGC) that makes up fungal cell walls. It is quite challenging to separate chitin from glucans during the extraction process because of their structural similarities. While the literature demonstrates few methods for the separation of chitin and glucans there is often inadequate characterization of its purity and properties making it unclear to understand whether the native properties of the material in the course of chitin isolation are preserved. The goal of this study is to investigate the chitin extraction from three different mushrooms- (white (Agaricus bisporus), shitake (Lentinus edodes), and oyster (Pleurotus ostreatus) using four different methods: 1. traditional pulping (using NaOH), 2. extraction with 1-ethyl-3-methylimidazolium acetate ionic liquid (IL), 3. pulping with 1-butyl-3-methylimidazolium hydrogen sulfate, and 4. isolation using deep eutectic solvent system (DES, [Cho]Cl – Lactic acid). A further focus will be on the characterization of this polymer to identify different properties and purity. Finally, we will conclude whether it is required to separate the chitin and glucans, or CGC can be used directly for materials’ preparation.