Chitin-glucan complex (CGC) is a

copolymer In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are some ...

( polysaccharide) that makes up

fungal A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

cell walls, consisting of covalently-bonded chitin and branched 1,3/1,6-ß-D-glucan. CGCs are alkaline-

insoluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubil ...

. Different species of fungi have different structural compositions of chitin and β-glucan making up the CGCs in their cell walls. Soil composition and other environmental factors can also affect the ratio of chitin to β-glucan found in the CGC. Fungal cell walls may also contain

chitosan Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit) and ''N''-acetyl-D-glucosamine (acetylated unit). It is made by treating the chitin shells of shrimp and other crustacean ...

-glucan complexes, which are similar copolymers but have chitosan instead of chitin. Chitin and chitosan are closely related molecules: greater than 40% of the polymer chain of chitin is made of

acetylated : In organic chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed ''acetate esters'' or simply ''acetates''. Deacetylation is the opposit ...

glucosamine Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most ...

units, whereas greater than 60% of chitosan is made of deacetylated glucosamine units. In their natural form, CGCs provide structural support to the fungal cell wall. Biomedical applications of CGCs have been studied, including the immunostimulant properties of '' A. fumigatus'', as well as successful

antibacterial An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

activity against ''S. typhimurium'' by CGCs from '' A. niger'' and ''M. rouxii''. There is some evidence that CGCs can act as an effective prebiotic, as it was tested on growing 100 different bifdobacterial strains as well as on rats ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

''. CGCs have many industrial applications, such as in food, cosmetics, and textiles industries, because they can be prepared easily without

toxin A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849 ...

s. As food additives, they are commonly used due to their ability to adsorb heavy metal ions. Additionally, CGCs are produced in high volume industrially because they can be broken down into their constitutive components by

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolys ...

, producing pure chitin (or chitosan) and β-glucans. Rather than being produced from animal parts, pure chitin can be extracted from the cell walls of the

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

Pichia pastoris ''Pichia pastoris'' is a species of methylotrophic yeast. It was found in the 1960s, with its feature of using methanol as a source of carbon and energy. After years of study, ''P. pastoris'' was widely used in biochemical research and biotech ...

, recently classified as Komagataella pastoris. Unlike chitin extracted from

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s, for example, this chitin contains no heavy metals. A study revealed that the complex exhibits traces of α-chitin in the molecular structure via x-ray diffraction. The similarities in structure and physical properties suggest that the complex is a suitable alternative to crustacean-based chitin as fungi are a more feasible and reliable source of raw materials.

References

Acetamides Biomolecules Biopesticides Polysaccharides {{biochemistry-stub