Prospects for Modifying the Structure of Chitin and Chitosan of Higher Mushroom to Expand Their Application Potential (A Review)

The review summarizes the scientific information on the chemical structure and properties of chitin and chitosan isolated from the mushrooms biomass and analyzes the directions for their modification for the application in food industry and medicine as antibacterial, antiviral, wound-healing, and anticoagulant agents. The features of the synthesis of chitin by mushroom of the Basidiomycota, Ascomycota, and Deuteromycota classes and the synthesis of chitosan by lower fungi of the Zygomycota class are covered. It is shown that higher mushroom contain chitin in their cell walls in the form of a chitin–glucan complex, while lower fungi (zygomycetes) contain chitin in the form of a chitosan–glucan complex. The active components of the substrates that affect the production of polysaccharides by mushroom are identified, specifically carbohydrates in the form of glucose, sucrose, and maltose, organic forms of nitrogen in the form of yeast extract and corn flour, mineral components in the form of dihydrogen phosphate and dipotassium hydrogen phosphate. Particular attention is paid to the methods for the isolation of chitin and its modification to chitosan, carboxymethyl and sulfo derivatives of chitin and chitosan polymers, as well as to detailed description of the physicochemical and biological properties of the polymers. The choice of appropriate conditions and reagents for carboxymethylation of chitin and chitosan makes it possible to obtain carboxymethyl chitin, N- and O-carboxymethyl chitosans, as well as N,O- or N,N-bis(carboxymethyl)chitosans. The biological properties and application of these groups of compounds are described. The properties and applications of carboxymethyl derivatives of chitin and chitosan strongly depend on their structure, degree of substitution, and arrangement of the amino or hydroxyl groups. Sodium monochloroacetate and monochloroacetic and glyoxalic acids are the main carboxymethylation reagents. Carboxymethyl derivatives of chitin and chitosan are used as drug delivery systems, antimicrobial agents, components of cosmetics and food products, as well as tissue engineering scaffolds. The modification of chitosan with sulfo groups gives chitosan 2-N-, 6-O-, and 3-O-sulfates sulfates and 2-N-6-O-disulfates. The main sulfonating agents are oleum, pyridine, and chlorosulfonic acid. Sulfonic derivatives of chitin and chitosan can be used to produce hemocompatible materials (with antithrombotic and antibacterial activities).