Enzymatic Synthesis ofP-Nitrophenyl β-Chitobioside

p-Nitrophenyl β-chitobioside (2) was prepared from p-nitrophenyl 2-acetamido-2--deoxy-β-D-glucopyranoside (1) using β-N-acetylhexosaminidase from Aspergillus oryzae. As minor by-product a (1→6)-linked regioisomer (3a) was formed. Addition of (NH4)2SO4 and organic co-solvents (acetonitrile, dioxane) substantially increased the yield.