Determination of glucosamine in fungal cell walls by high-performance liquid chromatography (HPLC)

Glucosamine (GlcN) is a major and valuable component in the cell wall of zygomycetes fungi. In this study, a time independent and accurate method was developed for the determination of GlcN. In this method, the cell wall was treated via a two-stage sulfuric acid process, and chitin and chitosan were fully deacetylated, partially depolymerized, and converted to GlcN oligosaccharides. Then, the oligosaccharides were deaminated to 2,5-anhydromannose using nitrous acid. Finally, 2,5-anhydromannose was analyzed by high performance liquid chromatography (HPLC). The determinations of pure GlcN solutions were stable at least for 10 days, while those of the conventional colorimetric method were not stable for more than one hour. The alkali insoluble material (AIM) of biomass of purely yeast-like, mostly yeast-like, and filamentous forms of the fungus Mucor indicus was analyzed by the developed method. The respective GlcN content of AIM of the fungus was 0.232, 0.204, and 0.458 (g/g).