Akram Zamani., Azam Jehianipour, Lars Edebo., Cales Niklasson, Mohammad Taherzadeh. Determination of glucosamine and N-acetyl glucosamine in fungal cell walls. Journal of Agricultural and Food Chemistry 2008; 56 (18): 8314-8318.

A new method was developed to determine glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc)
in materials containing chitin and chitosan, such as fungal cell walls. It is based on two steps of
hydrolysis with (i) concentrated sulfuric acid at low temperature and (ii) dilute sulfuric acid at high
temperature, followed by one-step degradation with nitrous acid. In this process, chitin and chitosan
are converted into anhydromannose and acetic acid. Anhydromannose represents the sum of GlcN
and GlcNAc, whereas acetic acid is a marker for GlcNAc only. The method showed recovery of
90.1% of chitin and 85.7-92.4% of chitosan from commercial preparations. Furthermore, alkali
insoluble material (AIM) from biomass of three strains of zygomycetes, Rhizopus oryzae, Mucor
indicus, and Rhizomucor pusillus, was analyzed by this method. The glucosamine contents of AIM
from R. oryzae and M. indicus were almost constant (41.7 ( 2.2% and 42.0 ( 1.7%, respectively),
while in R. pusillus, it decreased from 40.0 to 30.0% during cultivation from 1 to 6 days. The GlcNAc
content of AIM from R. oryzae and R. pusillus increased from 24.9 to 31.0% and from 36.3 to 50.8%,
respectively, in 6 days, while it remained almost constant during the cultivation of M. indicus (23.5 (
0.8%