Abstract: A chitooligosaccharide residue is disclosed which is represented by the formula: wherein m=1-20, n=1-20, m+n=2-21, and m/n=5-0.05, and R represents a saturated or unsaturated aliphatic acyl group of 3-24 carbon atoms.

Abstract: A partially N-acylated compound of chitooligosaccharide consisting essentially of 2 number of acyl glucosamine constituent units, m number of glucosamine constituent units and n number of acetyl glucosamine constituent units, wherein the ratios of l, m and n to the sum of l, m and n are in the respective ranges of 5 to 80%, 20 to 95%, and 0 to 50%, and having an OH radical attached at the 4 position or 1 position of the terminal unit of the composition.

Abstract: A process for producing deacetylase which comprises incubating a deacetylase-producing bacterium belonging to Vibrio cholerae in a IFO 15429 culture medium containing a carbon source, a nitrogen source, an inorganic salt and an inducer for producing the deacetylase and isolating the deacetylase from cells separated from said culture medium.

Abstract: A process for preparing a low-molecular weight chitosan which comprises adding chitosan to water containing a monobasic acid to prepare an intimate chitosan-water mixture and treating said mixture with cellulase.

Abstract: A cellulosic material is saccharified by cellulases and the resulting saccharified solution is acidified. Subsequently chitosan and/or partially deacetylated chitin are dissolved therein and the obtained solution is alkalified. Thus the cellulases are absorbed by the chitosan and/or partially deacetylated chitin. Further a cellulosic material is saccharified by at least one cellulase originating from a fungus belonging to the genus Aspergillus and at least either chitosan and/or partially deacetylated chitin are added to the resulting saccharified solution to thereby adsorb the cellulase by the chitosan and/or partially deacetylated chitin.