Alkyl beta-D-glucosaminides (RGlcN) were prepared by the novel direct transglycosylation reaction of chitosan and alcohol using the purified exo-beta-D-glucosaminidase from the chitosan-assimilating strain, Penicillium funiculosum KY616. Using the exo-beta-D-glucosaminidase, versatile synthetic intermediates, short and medium chain RGlcNs, were prepared in a maximum yield of higher than 480 mg/g-chitosan when chitosan and an alcohol were incubated at a temperature of 30 degrees C for 2 d.