A new thiamin glycoside, e.g., thiamin β-D-2-deoxy-2-acetamidoglucopyranoside was prepared by transglycosylation by β-N-acetylhexosaminidase from Aspergillus oryzae and characterized spectrally. Series of other fungal β-N-acetyl-hexosaminidases from A. awamori, A. tamari, A. terreus, and Penicillium oxalicum were shown to be able to synthesize the same compound in lower yields.