CP/MAS 13C NMR analysis of cellulase treated bleached softwood kraft pulp Original Research Article

Fully bleached softwood kraft pulps were hydrolyzed with cellulase (1,4-(1,3:1,4)-β-d-glucan 4-glucano-hydrolase, EC 3.2.1.4) from Trichoderma reesei. Supra-molecular structural features of cellulose during enzymatic hydrolysis were examined by using CP/MAS 13C NMR spectra in combination with line-fitting analysis. Different types of cellulose allomorphs (cellulose Iα, cellulose Iβ, para-crystalline) and amorphous regions were hydrolyzed to a different extent by the enzyme used. Also observed was a rapid initial phase for hydrolysis of regions followed by a slow hydrolysis phase. Cellulose Iα, para-crystalline, and non-crystalline regions of cellulose are more susceptible to enzymatic hydrolysis than cellulose Iβ during the initial phase. After the initial phase, all the regions are then similarly susceptible to enzymatic hydrolysis.