Abstract
Acetylcelluloses with different degrees of acetyl substitution (DS) were prepared by removing a part of the acetyl substituents from a commercial cellulose acetate in acidic conditions. First, the solubility of the prepared acetylcellulose was investigated in some organic solvents and their aqueous mixtures. The acetylcellulose samples with different DS were then treated in a buffer solution of pH 4.5 containing a commercial cellulase (from Trichoderma viride) for given times. Both the supernatant solution and/or the residue which existed as precipitates after the cellulase treatment were analyzed by means of viscosity measurements, high performance liquid chromatography, gel permeation chromatography, glucose detection and so on.
With the acetylcellulose having higher DS (>2.20), no direct evidence that it had been degraded by the cellulase were obtained. On the other hand, with the acetylcelluloses covering DS range from 0.58 to 2.19, the cleavage of the polymer chains occured to the extent depending on the DS. For DS=0.58_??_1.08, free glucose molecules were detected and its amount decreased clearly with increasing DS.
In conclusion, it was proved that cellulase undergoes the degradation of acetylcellulose, that had never been reported.
