Preparation and characterization of cationic and amphoteric mannans from Candida albicans

Cationic and amphoteric mannans from Candida albicans were prepared by chemical modification with (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC) and sodium chloroacetate under aqueous alkaline conditions. The optimal reaction conditions for mannan cationization were found to be 6 h, 60 °C, and NaOH/CHPTAC ratio of 1.0. Adjusting the molar ratio of cationization agent to anhydromannose unit, cationic and amphoteric mannans with degree of substitution ranging from 0.07 to 0.57 were obtained. Their structure was confirmed by elemental analysis as well as FTIR and NMR spectroscopies. Moderate decrease of molecular weight of both cationic and amphoteric mannans was recorded by size exclusion chromatography. With increasing level of modification, reduction of the antibody-binding capacity was observed by enzyme-linked immunosorbent assay.